WO2012133775A1 - Power storage element - Google Patents

Abstract

A power storage element provided with: an electrode body (10) configured by stacking a positive electrode plate (11) and a negative electrode plate (12) with a separator therebetween; a battery case (2) for housing the electrode body (10); and protective members (8) which are disposed between the end surfaces (13) parallel to the stacking direction of the positive electrode plate (11) and the negative electrode plate (12) of the electrode body (10) and the side walls (4) of a container (3) constituting the battery case (2) and which are formed from a material that has a higher melting temperature than the material forming the container (3). When high-temperature gas is produced in the interior of the electrode body (10) as a consequence of abnormal heat generation, the produced gas will flow along the plate surface direction of the positive electrode plate (11) and the negative electrode plate (12) and will be released from the end surfaces (13) of the electrode body (10). At that time, the released gas is received by the protective members (8) and does not reach the side walls (4) because the protective members (8) are disposed between the end surfaces (13) of the electrode body (10) and the side walls (4) of the container (3). As a consequence, the container (3) is prevented from becoming damaged and melting.

Description

Electricity storage element

The present invention relates to a power storage element.

Conventionally, a storage element formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween, an electrolytic solution, a case for storing the storage element in a state of being immersed in the electrolytic solution, and a connecting portion and an electrode plate of external connection terminals For example, a battery described in Patent Document 1 is known as an electric storage element including a current collecting member connected to the battery. *

JP 2005-209529 A

(Problems to be solved by the invention)
In this type of battery, it is possible to reduce the size and weight, it is advantageous in terms of cost, and the workability is good. Therefore, aluminum or an aluminum alloy is sometimes used as a case material. Many.

However, when the case is formed of such a relatively low melting point material, for example, when the battery is overcharged due to misuse, high temperature gas is released from the storage element due to abnormal heat generation, There is a concern that the case melts and breaks due to heat.

The present invention has been completed based on the above circumstances, and an object thereof is to provide a power storage element having a simple configuration and excellent safety.

(Means for solving problems)
The present invention provides a power storage element formed by laminating a positive electrode plate and a negative electrode plate, a case for housing the power storage element, an end surface parallel to the stacking direction of the positive electrode plate and the negative electrode plate in the power storage element, and the case. And a protective member formed of a material having a melting point higher than that of the material constituting the case.

Here, when a high-temperature gas is generated inside the electricity storage element due to abnormal heat generation, the generated gas flows along the plate surface direction of the positive electrode plate and the negative electrode plate, and is exposed to the outside of the electricity storage element at the positive electrode plate and the negative electrode plate. In the electric storage element, that is, from the end face parallel to the stacking direction of the positive electrode plate and the negative electrode plate, the electric storage element is discharged to the outside of the electric storage element. According to the present invention, since the protective member is disposed between the end face of the electricity storage element and the wall portion of the case, the released gas is received by the protective member. Thereby, it can suppress that a hot gas is sprayed directly on the wall part of a case, and can melt | disconnect and break a case.

The present invention may have the following configuration.

As a material for forming the protective member, a ceramic material can be preferably applied.
The present invention can be preferably applied when the material forming the case is a material having a relatively low melting point such as aluminum or an aluminum alloy.

Furthermore, the power storage element of the present invention may include an insulating sheet for packaging the power storage element. According to such a configuration, since the insulating sheet and the protective member are interposed between the wall portion of the case and the power storage element, the case can be more reliably prevented from being melted or damaged.

In addition, the power storage element may be a wound type formed by winding a laminate of the positive electrode plate and the negative electrode plate. In the winding type power storage element, the surfaces corresponding to “the end surfaces parallel to the stacking direction of the positive electrode plate and the negative electrode plate” are only both end surfaces in the winding axis direction. Therefore, a protective member may be disposed so as to face the two end faces, and the safety of the power storage element can be ensured with a simple configuration.

In addition, the case is provided with a safety valve that opens when the internal pressure of the case becomes a predetermined value or more, and the protective member is disposed on the surface facing the end surface of the power storage element. In which a passage having an open end on the side corresponding to the side on which the safety valve is provided may be formed.

According to such a configuration, the gas released from the end face of the electricity storage element is guided to this passage, quickly flows to the side where the safety valve is provided, and is released from the safety valve to the outside. Thereby, the time during which the released gas stays in the vicinity of the end face of the electricity storage element inside the case can be reduced, so that the case can be more reliably prevented from melting / damaging.

(The invention's effect)
ADVANTAGE OF THE INVENTION According to this invention, the electrical storage element excellent in safety | security with a simple structure can be provided.

FIG. 1 is an exploded perspective view of the battery according to the first embodiment. FIG. 2 is an exploded perspective view of the battery according to the second embodiment. FIG. 3 is an exploded perspective view of the battery in the third embodiment. FIG. 4 is an exploded perspective view of the battery in the first modification. FIG. 5 is a perspective view of a protective member provided with a rib in the second modification. FIG. 6 is a perspective view illustrating an example of a protective member provided with a rib in the third modification. FIG. 7 is a perspective view showing another example of the protective member provided with the ribs in the third modification.

<Embodiment 1>
The first embodiment will be described with reference to FIG.

[Basic battery configuration]
A battery 1 (corresponding to a power storage element) of the present embodiment includes a battery case 2 (corresponding to a case) having a predetermined volume, and an electrode body 10 (corresponding to a power storage element) accommodated in the battery case 2 together with an electrolyte. With.

The battery case 2 includes a container 3 that is formed in a square shape and whose upper surface is opened, and a lid 5 that is formed in a plate shape and seals the opening of the container 3. As a material for the container 3 and the lid 5, aluminum or an aluminum alloy is preferably used. The lid 5 is fixed to the opening of the container 3 by a method such as welding, pressure bonding, or adhesion using an adhesive.

The electrode body 10 accommodated in the battery case 2 is formed in a long cylindrical shape by winding a stack of a separator between a positive electrode plate 11 and a negative electrode plate 12. The electrode body 10 is housed inside the container 3 with its winding axis direction oriented in the horizontal direction (a direction parallel to the plate surface of the lid body 5).

Although not shown in detail in the positive electrode plate 11 and the negative electrode plate 12, one end portion of the current collector is connected to each other, and the other end portion of the current collector is electrically connected to the output terminals 6 </ b> A and 6 </ b> B fixed to the lid body 5. Connected.

In addition, the lid 5 is provided with a safety valve 7 that opens when the pressure inside the battery 1 exceeds a predetermined value and releases gas or the like to the outside of the battery 1.

[Protective member]
Inside the battery 1, a protective member 8 is provided for preventing melting and breakage of the container 3 when a high-temperature gas is released from the electrode body 10 due to abnormal heat generation.

The protective member 8 is formed in a plate shape, and in the electrode body 10, a pair of end surfaces 13, 13 parallel to the stacking direction of the positive electrode plate 11 and the negative electrode plate 12, and the end surface 13 in the container 3, 13 is inserted between the pair of side walls 4 and 4 facing each other. In the present embodiment, since the electrode body 10 is of a wound type, the stacking direction of the positive electrode plate 11 and the negative electrode plate 12 is the radial direction of the electrode body 10, and the end faces 13 and 13 parallel to this are It is the both end surfaces of the electrode body 10 in the axial direction.

The protective member 8 is formed to have approximately the same size as the side walls 4 and 4 of the container 3 and is large enough to cover the entire end surfaces 13 and 13 of the electrode body 10.

The material constituting the protective member 8 needs to have a higher melting point than the material constituting the container 3 and has a lower thermal conductivity than the material constituting the container 3. preferable. Moreover, in order to insulate between the positive electrode plate 11 and the negative electrode plate 12 exposed to the end surfaces 13 and 13 of the electrode body 10 and the container 3, and to avoid the short circuit between the positive electrode plate 11 and the negative electrode plate 12, insulation It is necessary to be a material. Furthermore, it is preferable that the material is not corroded by the electrolyte components. Specifically, a ceramic material such as silica or alumina, a glass cloth, a nonwoven fabric coated with a ceramic slurry and hardened can be preferably used, and ceramics can be particularly preferably used.

The preferred thickness of the protective member 8 varies depending on the type of material used and cannot be generally limited. For example, when the material used is ceramic, if the thickness is 0.5 mm or more, the container 3 is sufficiently melted and damaged. Can be prevented. Further, if the protective member 8 is too thick, the space for accommodating the electrode body 10 and the electrolytic solution inside the container 3 is reduced, and the battery capacity is reduced. Therefore, the thickness of the protective member 8 is 2 mm. The following is preferable.

[Battery case melting and breakage prevention effect by protective member]
When the battery is overcharged due to misuse or the like, high temperature gas may be generated inside the electrode body 10 due to abnormal heat generation. The generated gas flows along the plate surface direction of the positive electrode plate 11 and the negative electrode plate 12, and is ejected from both end surfaces 13, 13 toward the side walls 4, 4 of the container 3. At this time, since the protective members 8 and 8 are disposed between the both end faces 13 and 13 of the electrode body and the side walls 4 and 4 of the container 3, the ejected gas is received by the protective members 8 and 8. . Thereby, it can suppress that a hot gas is directly sprayed on the side walls 4 and 4 of the container 3, and can prevent the container 3 from melting and breaking.

The gas received by the protective members 8, 8 is guided upward through the surfaces of the protective members 8, 8, and is released to the outside from the safety valve 7 provided on the lid 5.

[Summary]
As described above, the battery 1 of the present embodiment includes the electrode body 10 in which the positive electrode plate 11 and the negative electrode plate 12 are stacked via the separator, the battery case 2 that accommodates the electrode body 10, and the electrode body 10. A material having a higher melting point than the material constituting the battery case 2, which is disposed between the end face 13 parallel to the stacking direction of the positive electrode plate 11 and the negative electrode plate 12 and the side wall 4 of the container 3 in the battery case 2. The protective member 8 formed by the above.

Here, when a high-temperature gas is generated inside the electrode body 10 due to abnormal heat generation, the generated gas flows along the plate surface direction of the positive electrode plate 11 and the negative electrode plate 12 and is released from the end surface 13 of the electrode body 10. The At this time, since the protective member 8 is disposed between the end face 13 of the electrode body 10 and the side wall 4 of the container 3, the released gas is received by the protective member 8. Thereby, it can suppress that a hot gas is sprayed directly on the side walls 4 and 4 of the container 3, and can prevent the melting and breakage of the battery case 2.

In particular, when the material forming the battery case 2 is a material having a relatively low melting point such as aluminum or an aluminum alloy, the provision of the protective member 8 is effective for preventing melting and breakage of the container 3. Is.

In the present embodiment, the electrode body 10 is a wound type formed by winding a laminate of a positive electrode plate 11 and a negative electrode plate 12 with a separator interposed therebetween. In such a wound electrode body 10, the end face 13 from which the gas is ejected is only both end faces in the axial direction of the electrode body 10. Therefore, the protective member 8 may be disposed so as to face the two end faces, and the safety of the battery 1 can be ensured with a simple configuration.

<Embodiment 2>
A second embodiment will be described with reference to FIG. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
Similar to the first embodiment, the battery 20 of the present embodiment includes a battery case 2 and an electrode body 10 accommodated in the battery case 2 together with an electrolytic solution.

The electrode body 10 of this embodiment is packaged by a resinous insulating sheet 21. The insulating sheet 21 is mainly used to insulate between the battery case 2 and the electrode body 10 and is preferably formed of a material having a certain degree of heat resistance. Specifically, polyimide, PPS (polyphenylene sulfide), or the like can be preferably used.

Protective member 8 is arranged inside the container 3. This protective member 8 is outside the insulating sheet 21 and is formed on the electrode body 10 with a pair of side walls 4, 4 facing a pair of end faces 13, 13 parallel to the stacking direction of the positive electrode plate 11 and the negative electrode plate 12. Inserted inside. As a result, the insulating sheet 21 and the protective member 8 are interposed between the pair of end surfaces 13 and 13 of the electrode body 10 and the pair of side walls 4 and 4 facing the end surfaces 13 and 13.

Also in the present embodiment, when a high-temperature gas is generated inside the electrode body 10 due to abnormal heat generation, the generated gas flows along the plate surface direction of the positive electrode plate 11 and the negative electrode plate 12 and from the end surface 13. It is ejected toward the side wall 4 of the container 3. At this time, since the insulating sheet 21 and the protective member 8 are interposed between the end face 13 of the electrode body 10 and the side wall 4 of the container 3, the ejected gas is received by the insulating sheet 21 and the protective member 8. It is done. Thereby, it can suppress that a hot gas is sprayed directly on the side walls 4 and 4 of the container 3, and can prevent the melting and breakage of the battery case 2.

In the present embodiment, since the insulating sheet 21 is interposed between the electrode body 10 and the protective member 8, the protective member 8 is not necessarily formed of an insulating material. However, if the protective member 8 is formed of an insulating material, the insulation between the electrode body 10 and the container 3 is ensured even if the insulating sheet 21 is torn due to the heat of the jetted gas. And since the short circuit with the positive electrode plate 11 and the negative electrode plate 12 can be avoided, it is preferable.

<Embodiment 3>
A third embodiment will be described with reference to FIG. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The battery 30 of the present embodiment includes the battery case 2 and the electrode body 10 accommodated in the battery case 2 together with the electrolytic solution, as in the first embodiment. In addition, the electrode body 10 is packaged by a resinous insulating sheet 21. The configuration of the insulating sheet 21 is the same as that of the second embodiment.

In the present embodiment, the protective member 8 is arranged inside the insulating sheet 21 so as to cover the pair of end faces 13, 13 parallel to the stacking direction of the positive electrode plate 11 and the negative electrode plate 12 in the electrode body 10. Yes. As a result, the insulating sheet 21 and the protective member 8 are interposed between the pair of end surfaces 13 and 13 of the electrode body 10 and the pair of side walls 4 and 4 facing the end surfaces 13 and 13.

Also in the present embodiment, when a high-temperature gas is generated inside the electrode body 10 due to abnormal heat generation, the generated gas flows along the plate surface direction of the positive electrode plate 11 and the negative electrode plate 12 and from the end surface 13. It is ejected toward the side wall 4 of the container 3. At this time, since the insulating sheet 21 and the protective member 8 are interposed between the end face 13 of the electrode body 10 and the side wall 4 of the container 3, the jetted gas is caused by the insulating sheet 21 and the protective member 8. I can receive it. Thereby, it can suppress that a hot gas is sprayed directly on the side walls 4 and 4 of the container 3, and can prevent the melting and breakage of the battery case 2.

<Modification 1>
As in the battery 40 shown in FIG. 4, the protective member 8 may be attached to the inner side surfaces of the side walls 4 and 4 in the container 3. According to such a configuration, since the protective member 8 is fixed inside the container 3, there is no rattling of the protective member 8 inside the container 3. In addition, workability during assembly is improved.

<Modification 2>
Like the protective member 50 shown in FIG. 5, grid-like ribs 51 for reinforcement may be provided on the entire plate surface.

<Modification 3>
In the protection member 52 shown in FIG. 6, ribs 53 and 54 that protrude from the both side edges and the lower edge toward the end face 13 are provided on the face facing the end face 13 of the electrode body 10. By forming the rib 53 in such a shape, a region surrounded by the rib 53 becomes a passage 55 that extends in the vertical direction and is opened upward.

When such a protective member 52 is applied to a battery similar to that of the above embodiment, when a high-temperature gas is generated inside the electrode body 10 due to abnormal heat generation, the generated gas is the positive electrode plate 11 and the negative electrode plate. 12 flows along the plate surface direction and is ejected from the end surface 13 toward the side wall 4 of the container 3. At this time, the ejected gas is received by the protective member 52 in the same manner as described above, and the melting and breakage of the container 3 is prevented. In addition, a passage 55 is formed on the surface of the protective member 52 that faces the end surface 13 and extends in the vertical direction and is open to the upper side (the side where the safety valve 7 is provided in the battery case 2). The jetted gas is guided to the passage 55 and quickly flows upward, and is discharged to the outside from the safety valve 7 provided on the lid 5 (the ceiling wall of the battery case 2). Thereby, since the time for which the ejected gas stays in the container 3 in the vicinity of the end face 13 of the electrode body 10 can be reduced, the melting and breakage of the container 3 can be more reliably prevented.

In addition, like the protective member 56 shown in FIG. 7, the passage 58 may be divided into a plurality of portions by forming ribs 57 extending in parallel to the ribs 53 between the ribs 53 on both side edges. FIG. 7 shows an example in which one rib 57 extending in the vertical direction is formed between the ribs 53 on both side edges and the passage 58 is divided into two. Two or more ribs extending in the direction may be formed, and the passage may be divided into three or more.

<Verification experiment>
An experiment for verifying the technical effect of this battery was conducted.
(1) Verification conditions A battery having the same configuration as that of Embodiment 1 was prepared. Further, as a comparative example, a battery having the same configuration as that of Embodiment 1 except that no protective member is provided was prepared. These batteries were overcharged to create an overheated state and the changes were verified.

(2) Verification result After a few tens of minutes, it was confirmed that a relatively low temperature gas was released from the safety valve in the battery provided with the protective member. On the other hand, in a battery not provided with a protective member, it was confirmed that a part of the short side surface of the container became high temperature, then part of it melted and high temperature gas was blown out.

As described above, by providing a protective member, even when high-temperature gas is released from the inside of the electrode body, it is possible to prevent damage to the container and provide a battery that can be used continuously with high safety. It has become possible.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
1) In the above embodiment, the protective member 8 has a size capable of covering the entire end surface 13 of the electrode body 10, but the protective member may have a size covering a part of the end surface. .

2) In the above embodiment, the electrode body 10 is housed in the container 3 with its winding axis direction in the horizontal direction (parallel to the plate surface of the lid 5). You may accommodate in the container toward the vertical direction (direction parallel to the plate | board surface direction of a cover body).

3) In the above embodiment, the electrode body 10 is a wound type. However, the electrode body may be a laminated type in which a plurality of positive plates and negative plates are stacked via a separator. In this case, the stacking direction of the positive electrode plate and the negative electrode plate is a direction orthogonal to the plate surface direction of the stacked positive electrode plate and negative electrode plate, and the end surface parallel to this excludes the front and back surfaces in the plate surface direction. There are four sides.

4) In Embodiment 2 and Embodiment 3 described above, the electrode body 10 is packaged by the insulating sheet 21, and the protective member 8 is disposed inside or outside the insulating sheet 21, but the position facing the end surface of the electrode body The electrode body may be packaged by a packaging member in which a protective member disposed on the substrate and an insulating sheet covering the surface excluding the end surface are integrated.

5) In the above embodiment, an example in which the power storage element is a battery has been described. However, the power storage element may be a capacitor with an electrochemical phenomenon, for example.

1. Battery (electric storage element)
2 ... Battery case
7 ... Safety valve 8 ... Protective member 10 ... Electrode body (storage element)
DESCRIPTION OF SYMBOLS 11 ... Positive electrode plate 12 ... Negative electrode plate 13 ... End surface 21 ... Insulation sheet 55, 58 ... Passage

Claims (7)

A power storage element formed by laminating a positive electrode plate and a negative electrode plate;
A case for housing the power storage element;
A protection element made of a material having a higher melting point than a material constituting the case, which is disposed between the case and the end face parallel to the stacking direction of the positive electrode plate and the negative electrode plate in the power storage element. An electricity storage device comprising the member. The electric storage element according to claim 1, wherein the material forming the protective member is a ceramic material. The power storage element according to claim 1 or 2, wherein a material forming the case is aluminum or an aluminum alloy. The electric storage element according to any one of claims 1 to 3, further comprising an insulating sheet for packaging the electric storage element. The electricity storage device according to any one of claims 1 to 4, wherein the electricity storage element is a wound type formed by winding a laminate of the positive electrode plate and the negative electrode plate. element. The electric storage element according to claim 5, wherein the protection member is disposed between at least one end face of the electric storage element in the winding axis direction and the case. The case is provided with a safety valve that opens when the pressure inside the case becomes a predetermined value or more,
The said protection member is formed in the surface facing the said end surface of the said electrical storage element with the channel | path which the edge part by the side corresponding to the side in which the said safety valve is provided in the said case is open | released. The power storage device according to any one of claims 6 to 6.

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