JP7010211B2 - Battery packaging materials, their manufacturing methods, and batteries - Google Patents

Description

The present invention relates to a packaging material for a battery, a method for manufacturing the same, and a battery.

Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for encapsulating a battery element such as an electrode or an electrolyte. Conventionally, metal packaging materials have been widely used for battery packaging.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones and the like, batteries are required to have various shapes, and are required to be thinner and lighter. However, the metal packaging material for batteries, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as a packaging material for batteries that can be easily processed into various shapes and can be made thinner and lighter, it is in the form of a film in which a base material / aluminum alloy foil layer / heat-sealing resin layer is sequentially laminated. Laminates have been proposed.

In such battery packaging materials, in general, recesses are formed by cold forming, and battery elements such as electrodes and electrolytic solutions are arranged in the space formed by the recesses, and the heat-sealing resin layers are arranged with each other. By heat-welding the battery, a battery in which the battery element is housed inside the packaging material for the battery can be obtained. However, such a film-shaped packaging material is thinner than a metal packaging material, and has a drawback that pinholes and cracks are likely to occur during molding. When pinholes or cracks occur in the battery packaging material, the electrolytic solution penetrates into the aluminum alloy foil layer to form a metal precipitate, which may result in a short circuit. It is indispensable for the packaging material for a battery to have a property that pinholes are unlikely to occur during molding, that is, excellent moldability.

For example, Patent Document 1 describes the first adhesion in a laminated packaging material including an inner layer made of a resin film, a first adhesive layer, an aluminum alloy foil layer, a second adhesive layer, and an outer layer made of a resin film. For deeper molding, by forming at least one of the agent layer and the second adhesive layer with an adhesive composition containing a resin having an active hydrogen group in the side chain, polyfunctional isocyanates, and a polyfunctional amine compound. It is disclosed that a highly reliable packaging material can be obtained.

Japanese Unexamined Patent Publication No. 2008-287971 International release 2004/108408A

In recent years, with the demand for smaller and thinner batteries, further thinning of the packaging material for batteries is required. However, when the thickness of the battery packaging material is reduced, there is a problem that pinholes and cracks are likely to occur in the barrier layer during molding.

The present inventors have made diligent studies to solve the above problems. As a result, it is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and at least one layer of the base material layer is formed of a polybutylene terephthalate film. The piercing strength X (N) when pierced from the base material layer side of the laminated body, which was measured by a method in accordance with the provisions of 1997, is the square root of the thickness Y (μm) of the polybutylene terephthalate film √. It has been found that the packaging material for a battery in which the value obtained by dividing by Y (√μm) is 3.90 N / √μm or more is particularly excellent in moldability. The first aspect of the present invention has been completed by further studies based on these findings.

That is, the first aspect of the present invention provides the invention of the following aspects.
Item 1A. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
At least one layer of the base material layer is formed of a polybutylene terephthalate film.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. A packaging material for batteries, wherein the value obtained by dividing by the square root √Y (√μm) is 3.90N / √μm or more.
Item 2A. The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. Item 1. The packaging material for a battery according to Item 1A.
Item 3A. Item 2. The packaging material for a battery according to Item 1A or 2A, wherein the polybutylene terephthalate film has a thickness Y of 10 μm or more.
Item 4A. Item 6. The packaging material for a battery according to any one of Items 1A to 3A, wherein the thickness of the laminate is 160 μm or less.
Item 5A. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminated body.
At least one layer of the base material layer is formed of a polybutylene terephthalate film, and the piercing strength when pierced from the base material layer side of the laminate, which is measured by a method according to JIS Z1707: 1997. The value obtained by dividing X (N) by the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film is 3.90N / √μm or more. Production method.
Item 6A. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1A to 4A.

Further, the present inventors consist of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and at least one layer of the base material layer is polybutylene terephthalate having a thickness of 20 μm or less. Further, the piercing strength X (N) when pierced from the base material layer side of the laminate, which is formed of a film and is measured by a method according to JIS Z1707: 1997, is the poly. It has been found that the packaging material for batteries in which the value obtained by dividing by the thickness Y (μm) of the butylene terephthalate film is 1.02 N / μm or more is also particularly excellent in moldability. The second aspect of the present invention has been completed by further studies based on these findings.

That is, the second aspect of the present invention provides the invention of the following aspects.
Item 1B. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
At least one layer of the base material layer is formed of a polybutylene terephthalate film having a thickness of 20 μm or less.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. A packaging material for batteries, wherein the value obtained by dividing by is 1.02 N / μm or more.
Item 2B. The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. Item 1. The packaging material for a battery according to Item 1B.
Item 3B. Item 2. The battery packaging material according to Item 1B or 2B, wherein the polybutylene terephthalate film has a thickness Y of 10 μm or more.
Item 4B. Item 6. The packaging material for a battery according to any one of Items 1B to 3B, wherein the thickness of the laminate is 160 μm or less.
Item 5B. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminated body.
At least one layer of the base material layer is formed of a polybutylene terephthalate film.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. A method for producing a packaging material for a battery, wherein the value obtained by dividing by is 1.02 N / μm or more.
Item 6B. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1B to 4B.

Further, for example, as described in Patent Document 2, a polyester film having a low heat shrinkage rate of -2 to 2% (180 ° C. environment) has been conventionally used as an exterior material of a lithium ion battery. ing. On the other hand, the present inventors investigated the cause of the tendency for pinholes and cracks to occur in the barrier layer during molding when the thickness became thin, and found that the internal stress and flexibility of the film contributed to the moldability. Underneath, by using a polybutylene terephthalate film having a very high heat shrinkage rate and high flexibility as compared with a conventionally used film, a packaging material for a battery in which the film and a barrier layer are laminated. It was also found that the formability of the product was particularly improved. The third aspect of the present invention has been completed by further studies based on these findings.

That is, the third aspect of the present invention provides the invention of the following aspects.
Item 1C. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
At least one of the substrate layers is polybutylene terephthalate in which both the heat shrinkage rate at 150 ° C. in one direction and the heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction are 3.0% or more. Battery packaging material composed of film.
Item 2C. Item 2. The packaging material for a battery according to Item 1C, wherein the polybutylene terephthalate film has a thickness of 10 μm or more.
Item 3C. Item 2. The packaging material for a battery according to Item 1C or 2C, wherein the thickness of the laminate is 160 μm or less.
Item 4 C. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminated body.
Polybutylene terephthalate having at least one of the substrate layers having a heat shrinkage rate at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. A method for manufacturing a packaging material for a battery, which is composed of a film.
Item 5C. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1C to 3C.
Item 6C. A polybutylene terephthalate film for use in at least one layer of the base material layer of a battery packaging material composed of a laminate including a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
In the atmosphere, the heat shrinkage rate at 150 ° C. in one direction and the heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction are both 3.0% or more.
Polybutylene terephthalate film for battery packaging materials.

According to the first aspect of the present invention, in a battery packaging material composed of a laminate including a substrate layer, a barrier layer, and a heat-sealing resin layer in this order, at least one layer of the substrate layer is polybutylene. The polybutylene is the piercing strength X (N) when pierced from the base material layer side of the laminate, which is formed of a terephthalate film and measured by a method in accordance with JIS Z1707: 1997. To provide a packaging material for a battery having excellent moldability by dividing the thickness Y (μm) of the terephthalate film by the square root √Y (√μm) and having a value of 3.90 N / √ μm or more. Can be done.

Further, according to the second aspect of the present invention, in a battery packaging material composed of a laminate including a substrate layer, a barrier layer, and a heat-sealing resin layer in this order, at least one layer of the substrate layer is. It is formed of a polybutylene terephthalate film having a thickness of 20 μm or less, and has a piercing strength X (N) when pierced from the base material layer side of the laminate, which is measured by a method according to JIS Z1707: 1997. ) Is divided by the thickness Y (μm) of the polybutylene terephthalate film and the value obtained is 1.02 N / μm or more, so that a packaging material for a battery having excellent moldability can be provided.

Further, according to the third aspect of the present invention, in a battery packaging material composed of a laminate including a substrate layer, a barrier layer, and a heat-sealing resin layer in this order, at least one layer of the substrate layer is. Molded by being composed of a polybutylene terephthalate film in which the heat shrinkage rate at 150 ° C. in one direction and the heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction are both 3.0% or more. It is possible to provide a packaging material for a battery having excellent properties.

It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a schematic diagram for demonstrating the measuring method of a heat shrinkage rate.

The packaging material for a battery according to the first aspect of the present invention is composed of a laminate having a substrate layer, a barrier layer, and a heat-sealing resin layer in this order, and at least one layer of the substrate layer is a polybutylene terephthalate film. The polybutylene terephthalate film is formed by the piercing strength X (N) when pierced from the base material layer side of the laminated body, which is measured by a method in accordance with the provisions of JIS Z1707: 1997. The value obtained by dividing by the square root √Y (√μm) of the thickness Y (μm) is 3.90 N / √ μm or more.

The battery packaging material according to the second aspect of the present invention is composed of a laminate having a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and at least one of the base material layers has a thickness of 20 μm. The piercing strength X (N) when pierced from the base material layer side of the laminate, which is formed of the following polybutylene terephthalate film and measured by a method according to JIS Z1707: 1997, is determined. , The value obtained by dividing the polybutylene terephthalate film by the thickness Y (μm) is 1.02 N / μm or more.

Further, the packaging material for a battery according to the third aspect of the present invention is composed of a laminate having a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and at least one of the base material layers is unidirectional. It is characterized in that it is composed of a polybutylene terephthalate film in which the heat shrinkage rate at 150 ° C. and the heat shrinkage rate at 150 ° C. in the other direction orthogonal to the above-mentioned one direction are both 3.0% or more.

Hereinafter, the battery packaging material of the present invention will be described in detail. In the following description, in the first to third aspects of the present invention, it is clearly stated that the matters in which the preferred embodiments are not the same are the matters relating to the respective embodiments, and the matters in which the preferred embodiments are common are specified. , Not specified.

1. 1. Laminated structure and physical properties of battery packaging material The battery packaging material 10 of the present invention is, for example, as shown in FIG. 1, a laminate having a base material layer 1, a barrier layer 3, and a heat-sealing resin layer 4 in this order. Consists of. In the battery packaging material of the present invention, the base material layer 1 is on the outermost layer side, and the heat-sealing resin layer 4 is on the innermost layer. That is, at the time of assembling the battery, the heat-sealing resin layers 4 located on the peripheral edge of the battery element are heat-sealed to seal the battery element, whereby the battery element is sealed.

As shown in FIG. 2, for example, the packaging material for a battery of the present invention has an adhesive layer 2 between the base material layer 1 and the barrier layer 3 for the purpose of enhancing their adhesiveness, if necessary. May be. Further, for example, as shown in FIG. 3, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-bondable resin layer 4 for the purpose of enhancing their adhesiveness, if necessary. Further, as shown in FIG. 4, a surface covering layer 6 or the like may be provided on the outside of the base material layer 1 (the side opposite to the heat-sealing resin layer 4), if necessary.

In the packaging material for a battery according to the first aspect of the present invention, at least one layer of the base material layer 1 is formed of a polybutylene terephthalate film, and the measurement is further carried out by a method in accordance with the provisions of JIS Z1707: 1997. , The piercing strength X (N) when pierced from the base material layer 1 side of the laminate constituting the packaging material for batteries is divided by the square root √Y (√μm) of the thickness Y of the polybutylene terephthalate film. (That is, the ratio (X / √Y) of the piercing strength X (N) of the laminate to the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film). It is 3.90 N / √ μm or more. The battery packaging material of the first aspect has excellent moldability by having such a specific configuration. The details of this mechanism are not always clear, but can be thought of as follows. That is, the ratio (X / √Y) of the piercing strength X (N) of the laminated body to the square root √Y (√μm) of the thickness Y of the polybutylene terephthalate film is as large as 3.90N / √μm or more. Therefore, it can be said that a large internal stress exists in the laminated body. Further, the polybutylene terephthalate film has higher flexibility than polyethylene terephthalate and the like. It is considered that these factors are combined and the laminate is gradually stretched while resisting the force applied during cold forming. Therefore, it is considered that the barrier layer 3 is also gradually stretched, so that the occurrence of pinholes and cracks is effectively suppressed.

From the viewpoint of further improving the moldability of the packaging material for batteries of the first aspect, the piercing strength X (N) of the laminate and the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film are used. The ratio (X / √Y) to and to is preferably about 4.00 (N / √μm) or more and 6.50 (N / √μm) or less, and more preferably 4.10 (N / √μm) or more 6 About .00 (N / √μm) or less can be mentioned.

Further, in the packaging material for a battery according to the second aspect of the present invention, at least one layer of the base material layer 1 is formed of a polybutylene terephthalate film having a thickness of 20 μm or less, and further conforms to the provisions of JIS Z1707: 1997. The piercing strength X (N) when pierced from the base material layer 1 side of the laminate constituting the battery packaging material, which was measured by the above method, is determined by the thickness Y (μm) of the polybutylene terephthalate film. The value obtained by dividing (that is, the ratio (X / Y) of the puncture strength X (N) of the laminated body to the thickness Y (μm) of the polybutylene terephthalate film) is 1.02 N / μm or more. be. The battery packaging material of the second aspect has excellent moldability by having such a specific configuration. The details of this mechanism are not always clear, but can be thought of as follows. That is, since the ratio (X / Y) of the piercing strength X (N) of the laminated body to the thickness Y (μm) of the polybutylene terephthalate film is as large as 1.02 (N / μm) or more, the first It can be said that a large internal stress exists in the laminated body as in the above aspect. Further, the polybutylene terephthalate film has higher flexibility than polyethylene terephthalate and the like. It is considered that these factors are combined and the laminate is gradually stretched while resisting the force applied during cold forming. Therefore, it is considered that the barrier layer 3 is also gradually stretched, so that the occurrence of pinholes and cracks is effectively suppressed. In the second aspect, when the thickness of polyethylene terephthalate is 20 μm or less, the ratio (X / Y)) is 1.02 N / μm or more, so that the moldability is improved. Will be done.

From the viewpoint of further enhancing the moldability of the packaging material for batteries of the second aspect, the ratio (X / Y) of the puncture strength X (N) of the laminate and the thickness Y (μm) of the polybutylene terephthalate film. The examples thereof are preferably 1.03 (N / μm) or more and 1.30 (N / μm) or less, and more preferably 1.06 (N / μm) or more and 1.20 (N / μm) or less. ..

Further, also in the packaging material for a battery according to the third aspect of the present invention, at least one layer of the base material layer 1 is formed of a polybutylene terephthalate film, and the measurement is further carried out by a method in accordance with the provisions of JIS Z1707: 1997. The piercing strength X (N) when pierced from the base material layer 1 side of the laminate constituting the packaging material for the battery is the square root √Y (√μm) of the thickness Y of the polybutylene terephthalate film. The ratio (X / √Y) of the value obtained by dividing by (that is, the piercing strength X (N) of the laminate and the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film). ) Is preferably 3.90 N / √ μm or more. The battery packaging material of the third aspect has even better moldability by having such a specific configuration in addition to the above-mentioned heat shrinkage property. The details of this mechanism can be considered in the same manner as in the first aspect described above.

Further, also in the battery packaging material of the first aspect and the third aspect of the present invention, at least one layer of the base material layer 1 is formed of a polybutylene terephthalate film having a thickness of 20 μm or less, and further, JIS Z1707: The thickness of the polybutylene terephthalate film is the piercing strength X (N) when pierced from the base material layer 1 side of the laminate constituting the battery packaging material, which is measured by a method in accordance with the 1997 regulations. The value obtained by dividing by Y (μm) (that is, the above ratio (X / Y)) is preferably 1.02 (N / μm) or more. The battery packaging material of the first aspect and the third aspect has further excellent moldability by further providing such a specific configuration. The details of this mechanism can be considered in the same manner as in the second aspect described above.

From the viewpoint of further enhancing the moldability of the packaging material for batteries according to the first aspect and the third aspect, the ratio of the puncture strength X (N) of the laminate to the thickness Y (μm) of the polybutylene terephthalate film. The (X / Y) is preferably 1.02 (N / μm) or more and 1.30 (N / μm) or less, and more preferably 1.05 (N / μm) or more and 1.20 (N / μm). The following are mentioned.

The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but the upper limit is set from the viewpoint of improving the moldability of the battery packaging material after reducing the thickness of the battery packaging material. The lower limit is preferably about 250 μm or less, more preferably about 200 μm or less, still more preferably about 160 μm or less, still more preferably about 120 μm or less, and the lower limit is preferably about 35 μm or more, more preferably 45 μm or more, still more preferably. 81 μm or more can be mentioned. The thickness range is preferably 35 μm or more and 250 μm or less, 45 μm or more and 250 μm or less, 81 μm or more and 250 μm or less, 35 μm or more and 200 μm or less, 45 μm or more and 200 μm or less, 81 μm or more and 200 μm or less, 35 μm or more. Examples thereof include about 160 μm or less, 45 μm or more and 160 μm or less, 81 μm or more and 160 μm or less, 35 μm or more and 120 μm or less, 45 μm or more and 120 μm or less, and 81 μm or more and 120 μm or less. According to the present invention, the moldability of the battery packaging material can be improved even when the thickness of the laminate constituting the battery packaging material of the present invention is, for example, about 250 μm or less. The battery packaging material of the present invention can contribute to the improvement of the energy density of the battery by reducing the thickness.

2. 2. Each layer forming the packaging material for batteries [base material layer 1]
In the packaging material for batteries of the present invention, the base material layer 1 is a layer located on the outermost layer side. In the present invention, at least one layer of the base material layer 1 is formed of a polybutylene terephthalate film.

The method for allowing a large internal stress to exist in the polybutylene terephthalate film is not limited, but one example is the use of a polybutylene terephthalate film having a large heat shrinkage rate. For example, the polybutylene terephthalate film used for the base material layer 1 has a heat shrinkage rate at 150 ° C. in one direction (planar direction of the film) of the polybutylene terephthalate film in the atmosphere and another direction orthogonal to the one direction (the other direction (the plane direction of the film)). It is preferable that the heat shrinkage rate at 150 ° C. (in the plane direction of the film) is 3.0% or more. By using a film having a heat shrinkage rate of 3.0% or more in these two directions, which is larger than that of the conventional polybutylene terephthalate film, it is possible to further effectively improve the moldability of the battery packaging material. It will be possible. The details of this mechanism are not always clear, but can be thought of as follows. That is, since the heat shrinkage rate in two directions is as large as 3.0% or more, it can be said that a large internal stress exists in the polybutylene terephthalate film. Further, the polybutylene terephthalate film has higher flexibility than polyethylene terephthalate and the like. Therefore, as in the above-mentioned mechanism, it is considered that the laminated body is gradually stretched while resisting the force applied during cold forming. Therefore, it is considered that the barrier layer 3 is also gradually stretched, so that the generation of pinholes and cracks is suppressed more effectively. The one direction in which the heat shrinkage rate is measured and the other direction orthogonal to the heat shrinkage rate are not particularly limited, but the direction having the largest heat shrinkage rate can be the one direction.

In the present invention, the heat shrinkage rate at 150 ° C. in one direction (plane direction of the film) and the heat shrinkage rate at 150 ° C. in the other direction (planar direction of the film) orthogonal to the one direction are both 3. When a polybutylene terephthalate film having a content of 0% or more is used, particularly excellent moldability can be imparted to the packaging material. For example, when the base material layer is composed of a single layer of polyethylene terephthalate film, which is widely used as a base material layer of a packaging material, there is a problem that pinholes are likely to be opened when the molding depth is increased. Further, when the base material layer is composed of a single layer of a nylon film which is also widely used, there is a problem that the chemical resistance and the insulating property are low. On the other hand, by using the above-mentioned polybutylene terephthalate film, the moldability is excellent as compared with the polyethylene terephthalate film, and the chemical resistance and the insulating property are superior as compared with the nylon film. The chemical resistance of the battery packaging material can be evaluated by, for example, the method described in Examples. The size of the test piece to be evaluated may be smaller than the size of 40 mm × 40 mm adopted in the examples.

In the polybutylene terephthalate film of the first aspect and the second aspect, the ratio of the heat shrinkage rate in the one direction to the heat shrinkage rate in the other direction (the heat shrinkage rate in the one direction and the heat shrinkage rate in the other direction). Of these, the ratio obtained by dividing a small value by a large value) is preferably about 0.6 or more and 1.0 or less, and more preferably 1.0. When the ratio of the heat shrinkage ratio is in such a range, the size of the heat shrinkage ratio in the two directions is well-balanced, so that the moldability of the packaging material can be further effectively improved.

From the viewpoint of further enhancing the moldability of the battery packaging material of the first aspect and the second aspect, the heat shrinkage of the polybutylene terephthalate film is 3.0% or more and 15.0% or less, more preferably. 4.0% or more and 12.0% or less can be mentioned. The heat shrinkage rate may be in the above range in either one of the above-mentioned directions and the other direction, but it is preferable that both directions are in the above range.

Further, in the packaging material for a battery according to the third aspect of the present invention, the base material layer 1 is a layer located on the outermost layer side. In the third aspect, at least one layer of the base material layer 1 is formed of the above-mentioned polybutylene terephthalate film of the present invention. In the present invention, the polybutylene terephthalate film has a heat shrinkage rate at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. Therefore, it is possible to impart particularly excellent moldability to the packaging material for batteries. For example, when the base material layer is composed of a single layer of polyethylene terephthalate film, which is widely used as a base material layer for packaging materials for batteries, there is a problem that pinholes are likely to be opened when the molding depth is increased. Further, when the base material layer is composed of a single layer of a nylon film which is also widely used, there is a problem that the chemical resistance and the insulating property are low. On the other hand, by using the above-mentioned polybutylene terephthalate film, the moldability is excellent as compared with the polyethylene terephthalate film, and the chemical resistance and the insulating property are superior as compared with the nylon film. The polybutylene terephthalate film used for the base material layer 1 in the present invention is the base of a battery packaging material composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order. It is useful as a polybutylene terephthalate film (polybutylene terephthalate film for battery packaging materials) for use in at least one layer of a material layer.

In the third aspect, the polybutylene terephthalate film used for the base material layer 1 is orthogonal to the heat shrinkage rate at 150 ° C. in one direction (plane direction of the film) of the polybutylene terephthalate film in the atmosphere. The heat shrinkage at 150 ° C. in the other direction (the plane direction of the film) is 3.0% or more. By using a battery packaging material having a heat shrinkage rate of 3.0% or more in these two directions, which is larger than that of the conventional polybutylene terephthalate film, the moldability of the battery packaging material is effective. It is possible to increase to. The details of this mechanism can be considered in the same manner as in the first aspect and the second aspect described above. The one direction in which the heat shrinkage rate is measured and the direction orthogonal to the one direction are not particularly limited, but the direction having the largest heat shrinkage rate can be the one direction.

In the polybutylene terephthalate film of the third aspect, the ratio of the heat shrinkage rate in the other direction to the heat shrinkage rate in the one direction (heat shrinkage rate in the other direction / heat shrinkage rate in the one direction) is 0. It is preferably 6.6 or more and 1.4 or less. When the ratio of the heat shrinkage ratio is in such a range, the size of the heat shrinkage ratio in the two directions is well-balanced, so that the moldability of the packaging material for the battery can be further effectively improved.

In the third aspect, from the viewpoint of further improving the moldability of the battery packaging material, the heat shrinkage of the polybutylene terephthalate film is preferably about 3.0% or more and 15.0% or less, more preferably 4. It may be about 0.0% or more and 12.0% or less.

In the present invention, the heat shrinkage of the polybutylene terephthalate film is a value measured by the following method. First, as shown in the schematic diagram of FIG. 5, a polybutylene terephthalate film having a square view in a plan view of 120 mm × 120 mm is used as a test piece 10A. On the surface of the test piece 10A, two straight lines M of about 100 mm are marked with a pen so as to be orthogonal to each other. At this time, the intersection of the two straight lines is located at the center of the polybutylene terephthalate film. In addition, each of the two straight lines is drawn so as to be parallel to the end edge of the test piece. Next, the detailed length of the two lines is measured using a glass scale (the measured value at this time is referred to as A). Next, the test piece 10A is placed in an oven (in the air) at 150 ° C., left for 30 minutes, and then taken out to a room temperature environment (25 ° C.). The removed test piece 10A is left in a room temperature environment (25 ° C.) for 30 minutes or more in the same standard state as before the test. Next, the detailed lengths of the two lines are measured using a glass scale (the measured value at this time is referred to as B). Calculation formula: (AB) / A × 100 is used to calculate the heat shrinkage rate in each of the two directions. When the size of the test piece is less than 120 mm × 120 mm, two straight lines shorter than the end edge of the test piece can be drawn and the heat shrinkage rate can be measured in the same manner.

The heat shrinkage of the polybutylene terephthalate film of the present invention can be adjusted by various methods. For example, the type of film forming method and the conditions at the time of film forming (for example, film forming temperature, stretching ratio, cooling temperature, cooling). It can be adjusted by the speed and the heat fixing temperature after stretching). Examples of the method for forming a polybutylene terephthalate film include a T-die method, a calendar method, and a tubular method. Among these, the tubular method is preferable from the viewpoint of increasing the heat shrinkage rate of the polybutylene terephthalate film.

In the first aspect and the third aspect, the thickness Y of the polybutylene terephthalate film is not particularly limited, but from the viewpoint of further improving the moldability of the battery packaging material, the lower limit is preferably about 1 μm or more. It is preferably about 4 μm or more, more preferably about 10 μm or more, and the upper limit is preferably about 40 μm or less, more preferably about 30 μm or less. The range of the thickness Y of the polybutylene terephthalate film is preferably 1 μm or more and 40 μm or less, 1 μm or more and 30 μm or less, 4 μm or more and 40 μm or less, 4 μm or more and 30 μm or less, 10 μm or more and 40 μm or less, 10 μm or more and 30 μm or less. Can be mentioned.

Further, in the second aspect, the thickness Y of the polybutylene terephthalate film is not particularly limited as long as it is 20 μm or less, but from the viewpoint of further improving the moldability of the battery packaging material, the lower limit is preferably about 10 μm. As described above, more preferably about 13 μm or more is mentioned, and the upper limit is preferably about 17 μm or less. The range of the thickness Y of the polybutylene terephthalate film is preferably 10 μm or more and 20 μm or less, 10 μm or more and 17 μm or less, 13 μm or more and 20 μm or less, and 13 μm or more and 17 μm or less.

As will be described later, in the present invention, when the base material layer 1 includes a plurality of polybutylene terephthalate films, the thickness Y of the polybutylene terephthalate film is the total thickness of all the polybutylene terephthalate films. be. However, the thickness of the adhesive layer provided between the films is not included in the thickness Y. The thickness Y (μm) of the polybutylene terephthalate film is a value measured by using a laser microscope with respect to a cross section in the thickness direction of the packaging material for a battery.

In the present invention, the base material layer 1 may be a single layer or may be composed of a plurality of layers. When the base material layer 1 is a single layer, the base material layer 1 is composed of a polybutylene terephthalate film. When the base material layer 1 is composed of a plurality of layers, at least one of the base material layers 1 is made of a polybutylene terephthalate film, and further has another layer. The polybutylene terephthalate film is composed of polybutylene terephthalate, a copolymerized polyester containing butylene terephthalate as a repeating unit, and the like. The copolymerized polyester having butylene terephthalate as the main body of the repeating unit is, specifically, following the copolymer polyester (hereinafter, polybutylene (terephthalate / isophthalate)) which polymerizes with butylene isophthalate using butylene terephthalate as the main body of the repeating unit. (Abbreviated), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decandicarboxylate) and the like. The polybutylene terephthalate film may contain a polyethylene terephthalate component, a polyester-based elastomer, or the like.

In the present invention, the other layer may be made of the above-mentioned polybutylene terephthalate film or may be made of another material. The other materials are not particularly limited as long as they have insulating properties, and are, for example, polyester (excluding polybutylene terephthalate), polyamide, epoxy resin, acrylic resin, fluororesin, and polyurethane. , Silicon resin, phenol resin, polycarbonate resin, polyetherimide, polyimide, and mixtures and copolymers thereof.

In the present invention, specific examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and a copolymerized polyester containing ethylene terephthalate as a repeating unit. Further, as the copolymerized polyester having ethylene terephthalate as the main body of the repeating unit, specifically, a copolymer polyester having ethylene terephthalate as the main body of the repeating unit and polymerizing with ethylene isophthalate (hereinafter, polyethylene (terephthalate / isophthalate)). (Abbreviated after), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) , Polyethylene (terephthalate / decandicarboxylate) and the like. Further, as another copolymerized polyester having butylene terephthalate as a repeating unit as a main body, polybutylene naphthalate and the like can be mentioned. These polyesters may be used alone or in combination of two or more. Polyester has an advantage that it has excellent electrolytic solution resistance and is less likely to cause whitening or the like due to adhesion of the electrolytic solution, and is preferably used as a material for forming the base material layer 1.

Further, in the present invention, the polyamide is specifically an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, a copolymer of nylon 6 and nylon 66; terephthalic acid and / Or hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide, such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid), which contains a structural unit derived from isophthalic acid. Aroma-containing polyamides such as polymethoxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); further lactam components and isocyanate components such as 4,4'-diphenylmethane-diisocyanate. Examples thereof include a polyamide obtained by copolymerizing the above, a polyesteramide copolymer or a polyether esteramide copolymer which is a copolymer of a copolymer of a copolymerized polyamide with polyester or polyalkylene ether glycol; and a copolymer thereof. These polyamides may be used alone or in combination of two or more. The stretched polyamide film has excellent stretchability, can prevent whitening due to resin cracking of the base material layer 1 during molding, and is suitably used as a material for forming the base material layer 1.

In the present invention, as a specific example when the base material layer 1 is formed by a plurality of layers, a multilayer structure in which a polybutylene terephthalate film and a polybutylene terephthalate film are laminated, or a polybutylene terephthalate film and a nylon film are laminated. Examples thereof include a multilayer structure in which polybutylene terephthalate film and a polyester film (excluding polybutylene terephthalate film) are laminated. For example, when the base material layer 1 is formed from two layers of resin film, a configuration in which a polybutylene terephthalate film and a polybutylene terephthalate film are laminated, a configuration in which a polybutylene terephthalate film and a nylon film are laminated, and a polybutylene terephthalate film are used. A structure in which a polyethylene terephthalate film is laminated is preferable. Further, since the polybutylene terephthalate film is difficult to discolor when the electrolytic solution adheres to the surface, for example, when the base material layer 1 has a multilayer structure including a nylon film, the base material layer 1 is on the barrier layer 3 side. It is preferable that the laminate has a nylon film and a polybutylene terephthalate film in this order.

In the present invention, when the base material layer 1 has a multilayer structure, each resin film may be adhered via an adhesive, or may be directly laminated without an adhesive. In the case of adhering without using an adhesive, for example, a method of adhering in a heat-melted state such as a coextrusion method, a sandwich laminating method, and a thermal laminating method can be mentioned. When adhering via an adhesive, the adhesive used may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a thermal pressure type, an electron beam curing type such as UV and EB, and the like. Specific examples of the adhesive include the same adhesives exemplified in the adhesive layer 2 described later. Further, the thickness of the adhesive can be the same as that of the adhesive layer 2.

In the present invention, from the viewpoint of improving the moldability of the battery packaging material, it is preferable that the lubricant is attached to the surface of the base material layer 1. The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of the substituted amide include N-oleyl palmitate amide, N-stearyl stearyl amide, N-stearyl oleate amide, N-oleyl stealic acid amide, N-stearyl erucate amide and the like. Further, specific examples of trimethylolamide include trimethylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstea. Examples thereof include acid amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-disteallyl adipic acid amides, and N, N'-distearyl sebasic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amides, ethylene biserukaic acid amides, hexamethylene bisoleic acid amides, N, N'-diorail adipic acid amides, and N, N'-diorail sevacinic acid amides. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more.

In the present invention, when the lubricant is present on the surface of the base material layer 1, the abundance thereof is not particularly limited, but is preferably about 3 mg / m ² or more, more preferably 4 mg at a temperature of 24 ° C. and a humidity of 60%. / M ² or more and about 15 mg / m ² or less, more preferably 5 mg / m ² or more and about 14 mg / m ² or less.

The thickness (total thickness) of the base material layer 1 is preferably about 4 μm or more, more preferably 6 μm, from the viewpoint of reducing the total thickness of the battery packaging material and making it a battery packaging material having excellent insulation. It is about 60 μm or less, more preferably 10 μm or more and 50 μm or less.

[Adhesive layer 2]
In the packaging material for batteries of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary in order to firmly bond them.

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive mechanism used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a thermal pressure type and the like.

Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; Resins; polyether adhesives; polyurethane adhesives; epoxy resins; phenolic resins; polyamide resins such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefins, carboxylic acid-modified polyolefins, metal-modified polyolefins, etc. Polyethylene resin, polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; urea resin, melamine resin and other amino resins; chloroprene rubber, nitrile rubber, styrene-butadiene rubber and other rubber ; Silicon-based resin and the like can be mentioned. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane-based adhesive is preferable.

The thickness of the adhesive layer 2 is not particularly limited as long as it functions as a layer for adhering, and examples thereof include about 1 μm or more and 10 μm or less, preferably about 2 μm or more and 5 μm or less.

[Barrier layer 3]
In the battery packaging material, the barrier layer 3 is a layer that functions as a barrier layer for improving the strength of the battery packaging material and preventing water vapor, oxygen, light, and the like from entering the inside of the battery. In the present invention, when the polybutylene terephthalate film having the predetermined heat shrinkage rate is provided in at least one layer of the base material layer 1, the packaging material can be used even when the thickness of the barrier layer 3 is so thin. It is possible to exhibit even better moldability.

Specific examples of the metal constituting the barrier layer 3 include aluminum, stainless steel, titanium, and the like, preferably aluminum. The barrier layer 3 can be formed of, for example, a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition films, or the like, and is formed of a metal foil. Is preferable, and it is more preferable to form it with an aluminum foil. From the viewpoint of preventing wrinkles and pinholes from occurring in the barrier layer 3 during the manufacture of battery packaging materials, the barrier layer may be, for example, annealed aluminum (JIS H4160: 1994 A8021HO, JIS H4160: It is more preferably formed of a soft aluminum foil such as 1994 A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O).

In the first aspect and the second aspect, the thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer such as water vapor, but is, for example, about 10 μm or more and 50 μm or less, preferably about 10 μm or more and 40 μm or less. Can be.

Further, also in the third aspect, the thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer such as water vapor, but is, for example, 10 μm or more and 100 μm or less, preferably 10 μm or more and 55 μm or less. It is preferably about 10 μm or more and 38 μm or less. In the third aspect, since the polybutylene terephthalate film having the predetermined heat shrinkage rate is provided in at least one layer of the base material layer 1, even when the thickness of the barrier layer 3 is so thin, even when the thickness of the barrier layer 3 is very thin. Battery packaging materials can exhibit excellent moldability.

Further, it is preferable that at least one surface, preferably both sides, of the barrier layer 3 is subjected to chemical conversion treatment in order to stabilize adhesion, prevent dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer. The chemical conversion treatment includes, for example, chromate treatment using a chromium compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium bicarbonate, acetylacetate chromate, chromium chloride, potassium sulfate chromium; phosphorus. Phosphoric acid treatment with a phosphoric acid compound such as sodium acid, potassium phosphate, ammonium phosphate, polyphosphoric acid; for an aminoated phenol polymer having repeating units represented by the following general formulas (1) to (4). Examples include the chemical conversion process. In the amination phenol polymer, the repeating unit represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Further, R ¹ and R ² are the same or different, respectively, and represent a hydroxyl group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the alkyl group and the hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different from each other. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the aminoated phenol polymer having the repeating unit represented by the general formulas (1) to (4) is, for example, preferably 500 or more and 1 million or less, and preferably 1000 or more and 20,000 or less. More preferred.

Further, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, a material in which metal oxides such as aluminum oxide, titanium oxide, cerium oxide and tin oxide and fine particles of barium sulfate are dispersed in phosphoric acid is coated. A method of forming a corrosion resistant layer on the surface of the barrier layer 3 by performing a baking treatment at 150 ° C. or higher can be mentioned. Further, a resin layer obtained by cross-linking a cationic polymer with a cross-linking agent may be further formed on the corrosion resistant layer. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, and polyallylamine. Alternatively, a derivative thereof, aminophenol and the like can be mentioned. As these cationic polymers, only one kind may be used, or two or more kinds may be used in combination. Examples of the cross-linking agent include a compound having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, a silane coupling agent, and the like. As these cross-linking agents, only one kind may be used, or two or more kinds may be used in combination.

As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion treatment may be performed in combination. Further, these chemical conversion treatments may be carried out by using one kind of compound alone or by using two or more kinds of compounds in combination. Among the chemical conversion treatments, chromate treatment and chromate treatment in which a chromium compound, a phosphoric acid compound, and an amination phenol polymer are combined are preferable. As the chromium compound, a chromic acid compound is preferable.

The amount of the acid-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing the above chromate treatment, the chromium compound is chromium per 1 m ² of the surface of the barrier layer 3. About 0.5 mg or more and about 50 mg or less in terms of conversion, preferably about 1.0 mg or more and about 40 mg or less, phosphorus compound is about 0.5 mg or more and about 50 mg or less in terms of phosphorus, preferably about 1.0 mg or more and about 40 mg or less, and an amination phenol polymer. Is preferably contained in a proportion of 1.0 mg or more and 200 mg or less, preferably 5.0 mg or more and 150 mg or less.

In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the barrier layer 3 by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer 3 is applied. It is carried out by heating so that the temperature is 70 ° C. or higher and 200 ° C. or lower. Further, before the chemical conversion treatment is applied to the barrier layer 3, the barrier layer 3 may be subjected to a degreasing treatment by an alkaline dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer 3.

[Heat-fused resin layer 4]
In the battery packaging material of the present invention, the heat-sealing resin layer 4 corresponds to the innermost layer, and is a layer in which the heat-sealing resin layers are heat-sealed to seal the battery element when the battery is assembled.

The resin component used in the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. Be done. That is, the heat-bondable resin layer 4 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. The fact that the heat-bondable resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near a wave number of 1760 cm-1 and a wave number of 1780 cm-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; homopolypropylene, a block copolymer of polypropylene (for example, a block copolymer of propylene and ethylene), and polypropylene. Polypropylene such as random copolymers of polyethylene (eg, random copolymers of propylene and ethylene); polyethylene-butene-propylene tarpolymers; and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Be done. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene and the like. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable. Styrene can also be used as the polyolefin.

The carboxylic acid-modified polyolefin is a polymer modified by block-polymerizing or graft-polymerizing the polyolefin with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

The carboxylic acid-modified cyclic polyolefin means that a part of the monomer constituting the cyclic polyolefin is copolymerized in place of α, β-unsaturated carboxylic acid or its anhydride, or α, β with respect to the cyclic polyolefin. -A polymer obtained by block-polymerizing or graft-polymerizing an unsaturated carboxylic acid or an anhydride thereof. The same applies to the cyclic polyolefin that is modified with carboxylic acid. The carboxylic acid used for the modification is the same as that used for the modification of the polyolefin.

Among these resin components, carboxylic acid-modified polyolefin is preferable; and carboxylic acid-modified polypropylene is more preferable.

The heat-bondable resin layer 4 may be formed of one type of resin component alone, or may be formed of a blended polymer in which two or more types of resin components are combined. Further, the heat-sealing resin layer 4 may be formed of only one layer, or may be formed of two or more layers with the same or different resin components.

Further, the heat-sealing resin layer 4 may contain a lubricant or the like, if necessary. When the heat-bondable resin layer 4 contains a lubricant, the moldability of the battery packaging material can be improved. The lubricant is not particularly limited, and a known lubricant can be used, and examples thereof include those exemplified in the above-mentioned base material layer 1. The lubricant may be used alone or in combination of two or more. The amount of the lubricant present on the surface of the heat-bondable resin layer 4 is not particularly limited, and from the viewpoint of improving the moldability of the electronic packaging material, it is preferably 10 mg / m at a temperature of 24 ° C. and a humidity of 60%. ² or more, 50 mg / m ² or less, more preferably 15 mg / m ² or more, 40 mg / m ² or less.

The thickness of the heat-sealing resin layer 4 is not particularly limited as long as it functions as a heat-sealing resin layer, but is preferably about 60 μm or less, more preferably about 15 μm or more and 40 μm or less.

[Adhesive layer 5]
In the packaging material for batteries of the present invention, the adhesive layer 5 is a layer provided between the barrier layer 3 and the heat-sealing resin layer 4 in order to firmly bond them, if necessary.

The adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the heat-sealing resin layer 4. As the resin used for forming the adhesive layer 5, the same adhesive as the adhesive exemplified in the adhesive layer 2 can be used in terms of the adhesive mechanism, the type of adhesive component, and the like. Further, as the resin used for forming the adhesive layer 5, polyolefin-based resins such as the polyolefins exemplified in the above-mentioned heat-sealing resin layer 4, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins can also be used. .. From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-bondable resin layer 4, the polyolefin is preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene. That is, the adhesive layer 5 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. The fact that the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near a wave number of 1760 cm-1 and a wave number of 1780 cm-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

The thickness of the adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer, but when the adhesive exemplified in the adhesive layer 2 is used, it is preferably about 2 μm or more and 10 μm or less, more preferably. 2 μm or more and 5 μm or less can be mentioned. Further, when the resin exemplified in the heat-sealing resin layer 4 is used, it is preferably about 2 μm or more and about 50 μm or less, more preferably about 10 μm or more and about 40 μm or less.

[Surface coating layer 6]
In the packaging material for a battery of the present invention, for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, etc., as necessary, above the base material layer 1 (barrier layer of the base material layer 1). A surface covering layer 6 may be provided on the side opposite to 3), if necessary. The surface coating layer 6 is a layer located on the outermost layer when the battery is assembled.

The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, a polyester resin, a urethane resin, an acrylic resin, an epoxy resin, or the like. Among these, the surface coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curable resin forming the surface coating layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, an additive may be added to the surface coating layer 6.

Examples of the additive include fine particles having a particle size of 0.5 nm or more and 5 μm or less. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the additive is also not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. As additives, specifically, talc, silica, graphite, kaolin, montmoriloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, Neodium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high Examples thereof include melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper and nickel. These additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. Further, the additive may be subjected to various surface treatments such as an insulation treatment and a high dispersibility treatment on the surface.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the surface coating layer 6 on one surface of the base material layer 1. When the additive is blended, the additive may be added to the two-component curable resin, mixed, and then applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions as the surface coating layer 6, and examples thereof include about 0.5 μm or more and 10 μm or less, preferably about 1 μm or more and 5 μm or less.

3. 3. Method for Manufacturing Battery Packaging Material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate in which each layer having a predetermined composition is laminated can be obtained. That is, in the method for producing a packaging material for a battery according to the first aspect of the present invention, at least the base material layer, the barrier layer, and the heat-sealing resin layer are laminated in this order to obtain a laminated body. It comprises a step, in which at least one layer of the substrate layer is formed of a polybutylene terephthalate film and pierced from the substrate layer side of the laminate as measured by a method according to JIS Z1707: 1997. The value obtained by dividing the piercing strength X (N) in the case by the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film may be 3.90N / √μm or more. ..

Further, in the method for producing a packaging material for a battery according to the second aspect of the present invention, at least the base material layer, the barrier layer, and the heat-sealing resin layer are laminated in this order to obtain a laminated body. The base material layer of the laminated body is provided with a step, and at least one layer of the base material layer is formed of a polybutylene terephthalate film having a thickness of 20 μm or less and measured by a method in accordance with the regulations of JIS Z1707: 1997. The value obtained by dividing the piercing strength X (N) when piercing from the side by the thickness Y (μm) of the polybutylene terephthalate film may be 1.02 N / μm or more.

Further, in the method for producing a packaging material for a battery according to a third aspect of the present invention, at least the base material layer, the barrier layer, and the heat-sealing resin layer are laminated in this order to obtain a laminated body. The process is provided, and at least one of the base materials has a heat shrinkage rate of at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. It may be composed of a polybutylene terephthalate film.

An example of the method for manufacturing the packaging material for a battery of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminated body A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or, if necessary, on the barrier layer 3 whose surface has been chemically converted, by a gravure coating method. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a roll coating method.

Next, the adhesive layer 5 and the heat-sealing resin layer 4 are laminated on the barrier layer 3 of the laminated body A in this order. For example, (1) a method of laminating the adhesive layer 5 and the heat-sealing resin layer 4 on the barrier layer 3 of the laminated body A by co-extruding (co-extruded laminating method), (2) separately, the adhesive layer 5 A method of forming a laminated body in which the heat-sealing resin layer 4 is laminated and laminating this on the barrier layer 3 of the laminated body A by a thermal laminating method. (3) Adhesive on the barrier layer 3 of the laminated body A. An adhesive for forming the layer 5 is laminated by an extrusion method, a solution-coated high-temperature drying method, a baking method, or the like, and a heat-sealing resin layer 4 previously formed into a sheet on the adhesive layer 5 is thermally formed. A method of laminating by a laminating method, (4) An adhesive layer while pouring a melted adhesive layer 5 between a barrier layer 3 of a laminated body A and a heat-bondable resin layer 4 formed in a sheet shape in advance. Examples thereof include a method of laminating the laminate A and the heat-sealing resin layer 4 via 5 (sandwich laminating method).

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface covering layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface covering layer 6.

As described above, the surface coating layer 6 provided as needed / the base material layer 1 / the adhesive layer 2 provided as needed / the barrier layer 3 whose surface is chemically treated as needed / as needed. A laminated body composed of the adhesive layer 5 / the heat-sealing resin layer 4 is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 or the adhesive layer 5, a hot roll contact type and hot air are further formed. It may be subjected to heat treatment such as a formula, a near infrared type or a far infrared type.

In the packaging material for batteries of the present invention, each layer constituting the laminated body improves or stabilizes film forming property, laminating process, suitability for secondary processing (pouching, embossing) of the final product, etc., as necessary. Therefore, surface activation treatments such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

4. Applications of Battery Packaging Materials The battery packaging materials of the present invention are used for packaging for sealing and accommodating battery elements such as positive electrodes, negative electrodes, and electrolytes. That is, a battery element having at least a positive electrode, a negative electrode, and an electrolyte can be accommodated in a package formed of the packaging material for a battery of the present invention to form a battery.

Specifically, a battery element having at least a positive electrode, a negative electrode, and an electrolyte is used in the battery packaging material of the present invention, with metal terminals connected to each of the positive electrode and the negative electrode projecting outward. A battery is formed by covering the peripheral edge of an element so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and heat-sealing and sealing the heat-sealing resin layers of the flange portion. Batteries using packaging materials are provided. When the battery element is housed in the package formed of the battery packaging material of the present invention, the heat-sealing resin portion of the battery packaging material of the present invention is on the inside (the surface in contact with the battery element). To form a package.

The battery packaging material of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the packaging material for a battery of the present invention is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, a lead livestock battery, a nickel / hydrogen livestock battery, and a nickel / cadmium livestock battery. , Nickel / iron livestock battery, nickel / zinc livestock battery, silver oxide / zinc livestock battery, metal air battery, polyvalent cation battery, condenser, capacitor and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets of the battery packaging material of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Example 1-5 and Comparative Example 1-2
<Manufacturing of packaging materials for batteries>
On a base material layer (each having a thickness shown in Table 1) made of a biaxially stretched polybutylene terephthalate film (PBT film) having a heat shrinkage rate (Table 1) measured by heat shrinkage rate measurement described later. A barrier layer made of an aluminum alloy foil (JIS H4160: 1994 A8021HO, thickness 35 μm) having been subjected to chemical conversion treatment on both sides was laminated by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one surface of the aluminum alloy foil to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, after laminating the adhesive layer and the base material layer on the barrier layer, an aging treatment was carried out to prepare a laminated body of the base material layer / adhesive layer / barrier layer. In the chemical conversion treatment of the aluminum foil used as the barrier layer, a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid was roll-coated so that the coating amount of chromium was 10 mg / m ² (dry mass). This was done by applying and baking on both sides of the aluminum foil by the method.

Next, on the barrier layer of the laminated body, an adhesive layer made of maleic anhydride-modified polypropylene resin (thickness 20 μm, arranged on the barrier layer side) and a heat-sealing resin layer made of random polypropylene resin (thickness 15 μm). , The innermost layer) was co-extruded to laminate an adhesive layer / heat-sealing resin layer on the barrier layer. Next, by heating at 190 ° C. for 2 minutes, a packaging material for a battery in which a base material layer, an adhesive layer, a barrier layer, an adhesive layer, and a heat-sealing resin layer were laminated in this order was obtained.

Comparative Example 3
<Manufacturing of packaging materials for batteries>
A barrier layer was laminated on the base material layer by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one surface of the aluminum alloy foil to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, after laminating the adhesive layer and the base material layer on the barrier layer, an aging treatment was carried out to prepare a laminated body of the base material layer / adhesive layer / barrier layer. In Comparative Example 3, a biaxially stretched polyethylene terephthalate film (PET film thickness 12 μm) was used as the base material layer. As the barrier layer, the same aluminum alloy foil as in Example 1-5 was used.

Next, on the barrier layer of the laminated body, an adhesive layer made of maleic anhydride-modified polypropylene resin (thickness 20 μm, arranged on the barrier layer side) and a heat-sealing resin layer made of random polypropylene resin (thickness 15 μm). , The innermost layer) was co-extruded to laminate an adhesive layer / heat-sealing resin layer on the barrier layer. Next, by heating at 190 ° C. for 2 minutes, a packaging material for a battery in which a base material layer, an adhesive layer, a barrier layer, an adhesive layer, and a heat-sealing resin layer were laminated in this order was obtained.

Comparative Example 4
<Manufacturing of packaging materials for batteries>
A barrier layer was laminated on the base material layer by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one surface of the aluminum alloy foil to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, after laminating the adhesive layer and the base material layer on the barrier layer, an aging treatment was carried out to prepare a laminated body of the base material layer / adhesive layer / barrier layer. In Comparative Example 4, a biaxially stretched nylon film (ONY film thickness 15 μm) was used as the base material layer. As the barrier layer, the same aluminum alloy foil as in Example 1-5 was used.

Next, on the barrier layer of the laminated body, an adhesive layer made of maleic anhydride-modified polypropylene resin (thickness 20 μm, arranged on the barrier layer side) and a heat-sealing resin layer made of random polypropylene resin (thickness 15 μm). , The innermost layer) was co-extruded to laminate an adhesive layer / heat-sealing resin layer on the barrier layer. Next, by heating at 190 ° C. for 2 minutes, a packaging material for a battery in which a base material layer, an adhesive layer, a barrier layer, an adhesive layer, and a heat-sealing resin layer were laminated in this order was obtained.

<Measurement of heat shrinkage rate>
The heat shrinkage of the film constituting each base material layer is a value measured by the following method. First, as shown in the schematic diagram of FIG. 5, the film constituting each base material layer of a 120 mm × 120 mm square view in a plan view was used as a test piece 10A. Two straight lines M of about 100 mm were marked on the surface of the test piece 10A with a pen so as to be orthogonal to each other. At this time, the intersection of the two lines was set to be located at the center of the film. In addition, the two straight lines are drawn so as to be parallel to the end edge of the test piece. Next, the detailed length of the two lines was measured using a glass scale (the measured value at this time is A). Next, the test piece 10A was placed in an oven (in the air) at 150 ° C., left for 30 minutes, and then taken out to a room temperature environment (25 ° C.). Next, the detailed lengths of the two lines were measured using a glass scale (the measured value at this time is referred to as B). The heat shrinkage rate in two directions was calculated by the calculation formula: (AB) / A × 100. The results are shown in Tables 1 and 2. In addition, when the heat shrinkage rate was measured in the same manner except that the temperature was set to 200 ° C instead of 150 ° C, for example, it was 26.5% in one direction and 23.2% in the other direction in Example 2 for comparison. In Example 2, it was 11% in one direction and 7% in the other direction.

<Measurement of piercing strength>
The piercing strength of each of the battery packaging materials obtained above was measured by a method in accordance with JIS Z1707: 1997. The puncture was performed from the base material layer side. As the piercing strength measuring device, ZP-50N (force gauge) and MX2-500N (measuring stand) manufactured by Imada Co., Ltd. were used. The results are shown in Tables 1 and 2.

<Evaluation of moldability>
Each battery packaging material obtained above was cut into a rectangle of 90 mm (MD) × 150 mm (TD) to prepare a sample. Using a molding die (female mold) having a diameter of 32 mm (MD) × 54 mm (TD) and a corresponding molding die (male mold), this sample was pressed at a pressing pressure of 0.9 MPa to 0.5 mm. Cold forming was performed on each of 20 samples by changing the forming depth in 0.5 mm increments from the forming depth. For the sample after cold forming, the deepest forming depth where pinholes and cracks do not occur in all 20 samples of aluminum foil is Amm, and the deepest forming depth where pinholes and the like occur in aluminum foil is pinholes and the like. The number of samples in which the above occurred was B, and the value calculated by the following formula was taken as the molding depth of the packaging material for the battery. The results are shown in Tables 1 and 2.
Molding depth = Amm + (0.5mm / 20 pieces) x (20 pieces-B pieces)

Regarding MD (Machine Direction) and TD (Transverse Direction) of the packaging material for batteries, the rolling direction of the aluminum foil is MD, and the direction perpendicular to the same plane as MD is TD. The rolling direction of the aluminum foil can be confirmed by the rolling marks of the aluminum foil, and the MD and TD of the battery packaging material can be confirmed from the rolling direction.

<Evaluation of chemical resistance>
From the battery packaging material obtained above, a test piece having a size of 40 mm × 40 mm was cut out. Next, one drop of an electrolytic solution (composed of a mixed solution of 1 M LiPF ₆ and ethylene carbonate, diethyl carbonate and dimethyl carbonate (volume ratio 1: 1: 1)) was dropped on the surface of the base material layer, and the temperature was 24. After leaving it for 4 hours in an environment of ° C. and a relative humidity of 50%, the electrolytic solution was wiped off with a cloth moistened with isopropyl alcohol, and changes in the surface were observed. At this time, the one having no change on the surface was designated as A, and the one having a discolored surface was designated as C. The results are shown in Table 1.

In Table 2, "PET" means a polyethylene terephthalate film. Further, "ONY" means a stretched nylon film.

As shown in Table 1, although the thickness of the aluminum alloy foil as the barrier layer is as thin as 35 μm, the substrate layer side of the laminate was measured by a method in accordance with the regulations of JIS Z1707: 1997. The value obtained by dividing the piercing strength X (N) when pierced from the above by the square root √Y (√μm) of the thickness Y (μm) of the polybutylene terephthalate film is 3.90N / √μm or more. In the packaging materials of Examples 1 to 5, the molding depth was deep and the moldability was excellent.

Further, as shown in Table 1, the piercing strength X (N) when pierced from the base material layer side of the laminated body, measured by a method in accordance with the provisions of JIS Z1707: 1997, is 20 μm or less in thickness. The molding depth of the packaging materials of Examples 1 to 4, which is a value obtained by dividing by the thickness Y (μm) of the polybutylene terephthalate film and has a ratio (X / Y) of 1.02 N / μm or more. It was deep and had excellent moldability.

Further, in the packaging materials of Examples 1 to 5 using a polybutylene terephthalate film having a heat shrinkage rate of 3% or more in both directions measured under the predetermined conditions, the molding depth is deep and the moldability is excellent. rice field.

On the other hand, in Comparative Examples 1 and 2 in which the ratio (X / √Y) is less than 3.90 (N / √μm), the molding depth is 4.8 mm or less, which is compared with Examples 1 to 5. It was inferior in formability. Further, in the case where the thickness of the PBT film is 20 μm or less, the ratio (X / Y) is less than 1.02 (N / μm) in Comparative Examples 1 and 2, as compared with Examples 1 to 4. It was inferior in formability. Further, in Comparative Examples 1 and 2 using the polybutylene terephthalate film having a heat shrinkage rate of less than 3% in any one of the above, the molding depth was 4.8 mm or less, which was compared with Examples 1 to 5. It was inferior in moldability.

Further, as shown in Table 2, in Comparative Example 3 in which a polyethylene terephthalate film was used instead of the polybutylene terephthalate film as the base material layer, the ratio (X / √Y) was 3.90 (N / √). It was less than μm), one of the heat shrinkage ratios was less than 3%, and the molding depth was 3.8 mm, which was inferior in moldability as compared with Examples 1 to 5. In Comparative Example 4 in which a nylon film was used instead of the polybutylene terephthalate film as the base material layer, the chemical resistance was inferior.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-sealing resin layer 5 Adhesive layer 6 Surface coating layer 10 Battery packaging material

Claims (11)

It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
At least one layer of the base material layer is formed of a polybutylene terephthalate film.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. The value obtained by dividing by the square root √Y (√μm) of is 3.90N / √μm or more.
The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate of 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. Is a packaging material for batteries. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
At least one layer of the base material layer is formed of a polybutylene terephthalate film having a thickness of 20 μm or less.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. The value obtained by dividing by is 1.02 N / μm or more, and
The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate of 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. Is a packaging material for batteries. It is composed of a laminate having at least a base material layer, a barrier layer , and a heat-sealing resin layer in this order.
At least one of the substrate layers is polybutylene terephthalate in which both the heat shrinkage rate at 150 ° C. in one direction and the heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction are 3.0% or more. Battery packaging material composed of film. The packaging material for a battery according to any one of claims 1 to 3, wherein the polybutylene terephthalate film has a thickness Y of 10 μm or more. The packaging material for a battery according to any one of claims 1 to 4, wherein the thickness of the laminate is 160 μm or less. An adhesive layer is provided between the barrier layer and the heat-sealing resin layer.
The battery packaging material according to any one of 1 to 5, wherein the adhesive layer contains a polyolefin resin. An adhesive layer is provided between the barrier layer and the heat-sealing resin layer.
The battery packaging material according to any one of 1 to 6, wherein the adhesive layer has a thickness of 10 μm or more. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminated body.
At least one layer of the base material layer is formed of a polybutylene terephthalate film.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. The value obtained by dividing by the square root √Y (√μm) of is 3.90N / √μm or more.
The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. A method for manufacturing packaging materials for batteries. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminated body.
At least one layer of the base material layer is formed of a polybutylene terephthalate film having a thickness of 20 μm or less.
The piercing strength X (N) when pierced from the substrate layer side of the laminate, measured by a method according to JIS Z1707: 1997, is the thickness Y (μm) of the polybutylene terephthalate film. The value obtained by dividing by is set to 1.02 N / μm or more.
The polybutylene terephthalate film has a heat shrinkage rate of the polybutylene terephthalate film at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. A method for manufacturing packaging materials for batteries. At least, it includes a step of laminating the base material layer, the barrier layer , and the heat-sealing resin layer in this order to obtain a laminated body.
Polybutylene terephthalate having at least one of the substrate layers having a heat shrinkage rate at 150 ° C. in one direction and a heat shrinkage rate at 150 ° C. in the other direction orthogonal to the one direction of 3.0% or more. A method for manufacturing a packaging material for a battery, which is composed of a film. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of claims 1 to 7.

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