WO2019031117A1 - Non-aqueous electrolyte battery - Google Patents

Abstract

A non-aqueous electrolyte battery disclosed in the present application is provided with a positive electrode, a negative electrode, a non-aqueous electrolytic solution and a separator, wherein the positive electrode contains at least two positive electrode active materials, at least one of the positive electrode active materials contains a lithium-containing nickel layered oxide, the positive electrode active materials contain, as a whole, Li, Ni and a metal M that is different from Li or Ni, a molar ratio Ni/(Ni+M) is 0.5 to 0.9 inclusive wherein the molar ratio Ni/(Ni+M) is a ratio of the total Ni amount to the sum total of the total Ni amount and the total metal M amount in the whole amount of the positive electrode active materials, the negative electrode contains an Al active layer, a Li-Al alloy is formed on the surface side of the Al active layer, and the non-aqueous electrolytic solution contains a lithium salt and an organic solvent.

Description

Non-aqueous electrolyte battery

The present invention relates to a non-aqueous electrolyte battery having good high temperature storage characteristics.

Non-aqueous electrolyte batteries are utilized in various applications by taking advantage of properties such as high capacity and high voltage. In particular, in recent years, the demand for non-aqueous electrolyte batteries for in-vehicle devices has increased.

Conventionally, as a power source of electronic devices for vehicles, the storage characteristics are better than general-purpose non-aqueous electrolyte secondary batteries, and there is almost no decrease in capacity even when stored for several years or longer. An electrolyte primary battery is used.

As the negative electrode active material of the non-aqueous electrolyte primary battery, metal lithium or a lithium alloy such as a Li-Al (lithium-aluminum) alloy is used, but even in the non-aqueous electrolyte secondary battery, the negative electrode active material is used. Since a lithium alloy can be used as the substance, an aluminum plate is used to form a negative electrode, or a clad material composed of a metal capable of absorbing and desorbing lithium and a dissimilar metal not capable of absorbing and desorbing lithium is used. It has also been proposed to realize stabilization of the battery characteristics by performing the above (patent documents 1 and 2).

On the other hand, in order to reduce battery swelling after high temperature storage at a high capacity, the total molar ratio of all nickel to all lithium in the whole amount of positive electrode active material is set to 0.05 to 1.0, and a non-aqueous electrolyte A lithium secondary battery to which a specific phosphonoacetate compound is added has been proposed (Patent Document 3).

In addition, lithium secondary batteries using two or more lithium-containing transition metal oxides with different average particle sizes have been proposed for the purpose of improving the reliability such as high capacity, excellent charge / discharge cycle characteristics, and safety. (Patent Document 4).

In addition, in order to be able to charge repeatedly and to improve the storage characteristics in a high temperature environment, it has a laminate containing a metal base layer not alloyed with Li and an Al active layer on both sides of the metal base layer. A non-aqueous electrolyte battery has been proposed which uses a negative electrode in which a Li—Al alloy is formed on the surface side of an Al active layer (Patent Document 5).

Furthermore, for the purpose of improving load characteristics at low temperatures after high temperature storage, a non-aqueous electrolyte battery is proposed in which a non-aqueous electrolyte contains a phosphoric acid compound such as tris (trimethylsilyl) phosphate (Patent Document 6).

Unexamined-Japanese-Patent No. 8-293302 Japanese Patent Application Laid-Open No. 10-106628 International Publication No. 2012/014998 JP 2007-287658 A International Publication No. 2016/039323 International Publication No. 2017/002981

On the other hand, even if an aluminum plate or a clad material is used as the negative electrode as described above, stabilization of the characteristics of the non-aqueous electrolyte secondary battery can not always be realized.

The present invention has been made in view of the above circumstances, and provides a non-aqueous electrolyte battery having good storage characteristics under a high temperature environment.

The non-aqueous electrolyte battery of the present invention is a non-aqueous electrolyte battery including a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, and the positive electrode contains at least two or more types of positive electrode active materials, And at least one kind of lithium-containing nickel layered oxide, wherein the positive electrode active material contains Li, Ni, and a metal M other than Li and Ni as a whole, and in the total amount of the positive electrode active material When the ratio of the total amount of Ni to the total amount of the total amount of Ni and the total amount of metal M is represented by molar ratio Ni / (Ni + M), the molar ratio Ni / (Ni + M) is 0.5 or more and 0.9 or less, The negative electrode includes an Al active layer, a Li-Al alloy is formed on the surface side of the Al active layer, and the non-aqueous electrolyte contains a lithium salt and an organic solvent.

According to the present invention, it is possible to provide a non-aqueous electrolyte battery having good storage characteristics in a high temperature environment.

FIG. 1 is a cross-sectional view schematically showing an example of the negative electrode precursor used in the non-aqueous electrolyte battery of the embodiment of the present invention. FIG. 2 is a plan view schematically showing the non-aqueous electrolyte battery of the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line II of FIG.

An embodiment of the non-aqueous electrolyte battery of the present invention will be described. The embodiment of the non-aqueous electrolyte battery of the present invention includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, and the positive electrode includes at least two or more positive electrode active materials, and at least one of the positive electrode active materials. Is a lithium-containing nickel layered oxide, and the positive electrode active material contains Li, Ni, and a metal M other than Li and Ni as a whole, and the total amount of Ni and the total amount of the positive electrode active material are When the ratio of the total Ni amount to the total amount of the total amount of metal M is represented by molar ratio Ni / (Ni + M), the molar ratio Ni / (Ni + M) is 0.5 or more and 0.9 or less. A layer is formed, and a Li—Al alloy is formed on at least the surface side of the Al active layer, and the non-aqueous electrolyte contains a lithium salt and an organic solvent.

The non-aqueous electrolyte battery of the present embodiment can improve the storage characteristics under a high temperature environment by adopting the above configuration.

Li (metal Li) and Li-Al alloy (an alloy of Li and Al) have lower acceptability of Li (Li ion) than carbon materials, and a non-aqueous electrolyte solution using this as a negative electrode active material In the secondary battery, when charge and discharge are repeated, the capacity is likely to be reduced early. From such a thing, carbon materials, such as graphite, are widely used as a negative electrode active material in the conventional non-aqueous-electrolyte secondary battery assumed to use repeatedly performing charging / discharging.

However, in a non-aqueous electrolyte secondary battery using a carbon material as a negative electrode active material, self-discharge tends to occur, and when stored in a charged state, capacity reduction tends to occur.

From these facts, as a battery used for a vehicle-mounted device, the storage characteristic is better than that of a conventional non-aqueous electrolyte secondary battery, and the non-aqueous electrolyte has almost no capacity reduction even when stored over a long period of several years or more Primary batteries are applied.

On the other hand, even in such applications, because of ease of maintenance, etc., it is possible to charge the battery several times to several tens of times, even if it is not required to repeat many charging and discharging like normal secondary batteries. There is a need for possible battery applications.

Therefore, in the non-aqueous electrolyte battery of the present embodiment, high storage characteristics and high capacity can be realized even when used in a high temperature environment such as in-vehicle use, and the number of times can be increased to some extent. The Li-Al alloy formed on the surface side of the Al active layer was used as a negative electrode active material so as to be able to charge the battery.

Furthermore, in the non-aqueous electrolyte battery of the present embodiment, a positive electrode is used which uses two or more positive electrode active materials containing a lithium-containing nickel layered oxide and the total amount of Ni in the total amount of the positive electrode active material is within a specific range. Do.

Lithium cobaltate is generally used as the positive electrode active material used for the non-aqueous electrolyte battery. However, in a secondary battery using lithium cobaltate as a positive electrode active material, elution of metal (cobalt) occurs when stored under high temperature in a charged state. As a result, the positive electrode active material that can contribute to charge and discharge decreases, and the discharge capacity thereafter decreases. Furthermore, the battery is expanded due to the generation of gas as the metal (cobalt) is eluted.

However, when using two or more types of positive electrode active materials containing a lithium-containing nickel layered oxide and setting the total amount of Ni in the total amount of positive electrode active materials to a specific range, the battery can be charged even at high temperatures. It is difficult for metal elution to occur. Therefore, it is possible to suppress the discharge capacity decrease and the gas generation accompanying it.

As described above, in the present embodiment, the storage property improvement action by the Al active layer and the gas generation suppression action by using the positive electrode active material function in a synergistic manner, so that a high temperature for a long time, for example, one month Even after storage, the battery can be made to have a small swelling (small volume change).

Hereinafter, each component of the non-aqueous electrolyte battery of the present embodiment will be described.

<Negative electrode>
As a first method for forming the negative electrode according to the non-aqueous electrolyte battery of the present embodiment, a metal base layer (hereinafter, also simply referred to as a “base layer”) not alloyed with Li and an Al metal layer ( Hereinafter, a laminate (a negative electrode precursor) in which a Li layer is formed by a method such as bonding Li foil to the surface of an Al layer of a laminated metal foil formed by bonding only with “Al layer”) And as a second method, there is a method using only a laminated metal foil (negative electrode precursor) formed by bonding a base material layer and an Al layer without bonding Li foils. . The first method and the second method are methods of using a current collector for the negative electrode in order to stabilize the shape of the negative electrode at the time of discharge and to facilitate the next charging. On the other hand, as a third method, there is a method of using only an Al foil as a negative electrode precursor without using a current collector for the negative electrode. First, the first method and the second method will be described.

In a battery using a Li-Al alloy as the negative electrode active material, for example, an Li foil (including a Li alloy foil unless otherwise specified. The same applies to the following) and an Al foil (including an Al alloy foil unless otherwise specified). And the same are introduced into the battery, and Li and Al are reacted with each other in the coexistence of the non-aqueous electrolytic solution to form a Li—Al alloy. However, when the metal foil [Cu (copper) foil, Cu alloy foil, etc.] to be a current collector is further inserted into the battery by simply overlapping the laminate of Li foil and Al foil, after storage (especially high temperature) After storage under the environment), the internal resistance of the battery is increased and the storage characteristics are not sufficiently improved.

This is because when the Li-Al alloy is formed of a laminate of Li foil and Al foil in the battery, the volume change occurs or the Li-Al alloy is formed to cause pulverization, so that the negative electrode is not made. This is because the water electrolyte solution is easily absorbed to cause a volume change, and adhesion between the layer of the Li—Al alloy (Al foil) and the current collector can not be secured.

On the other hand, an Al metal layer (such as Al foil) for forming a Li-Al alloy and a metal base layer (such as Cu foil) that is not alloyed with Li acting as a current collector are bonded in advance. Further, a method (first method) in which a Li layer (Li foil or the like) is laminated on the surface of the Al metal layer, and Li in the Li layer and Al in the Al metal layer are reacted (first method) A method of electrochemically reacting Al of the Al metal layer with Li ions in a non-aqueous electrolytic solution by using a joined body of the layer and the metal base layer as it is for assembly of a battery and charging after assembly The Al metal layer is formed by making at least the surface side of the Al metal layer into a Li—Al alloy according to the method 2) or the like, and the Al active in which the Li—Al alloy layer is formed on at least the surface of the Al metal layer Convert layers, By the the surface of the Shokumoto material layer Al active layer has a negative electrode that is bonded can be obtained suppressing an increase in internal resistance during storage.

In addition, by bonding the Al metal layer and the metal base layer in advance, deformation of the negative electrode accompanying formation of a Li-Al alloy on at least the surface side of the Al metal layer to form an Al active layer It is also possible to suppress (such as bending) to some extent.

The base layer can be made of a metal such as Cu, Ni, Ti, Fe, or an alloy of such an element and another element (however, an alloy such as stainless steel which does not react with Li).

Specifically, the base material layer is formed of a foil, a vapor deposition film, a plating film or the like of the metal or alloy.

The Al layer can be composed of pure Al or an Al alloy having an additive element for the purpose of improving the strength, and more specifically, it is composed of a foil, a deposited film, a plating film, etc. .

For the formation of the Li layer, a method of bonding a Li foil to the surface of the Al layer, a method of forming a vapor deposition film of Li, or the like can be used.

FIG. 1 is a cross-sectional view schematically showing an example of a laminate (negative electrode precursor) for forming a negative electrode used in the non-aqueous electrolyte battery of the present embodiment. In FIG. 1, in the negative electrode precursor 100, the Li foils 102 and 102 are attached to the surfaces of the Al layers 101b and 101b of the laminated metal foil 101 formed by bonding the Al layers 101b and 101b on both surfaces of the base layer 101a. It is a laminated body formed by being put together.

In the non-aqueous electrolyte battery in which the negative electrode precursor is used to form the negative electrode, Li in the Li foil and Al in the Al layer react with each other in the coexistence of the non-aqueous electrolyte to bond the Li foil in the Al layer. A Li—Al alloy is formed on the surface of the side (separator side), and the Al layer changes to an Al active layer. That is, at least the surface side (Li foil side) of the Al active layer of the negative electrode is a Li-Al alloy formed in the non-aqueous electrolyte battery.

In the negative electrode precursor, in the laminated metal foil formed by bonding the base material layer and the Al layer, the Al layer may be bonded to one side of the base material layer, and as shown in FIG. An Al layer may be bonded to both sides of the layer.

As shown in FIG. 1, when the Al layer is joined to both sides of the base layer and the Li-Al alloy is formed on the surface side of both Al layers, the Al layer is formed on one side of the base layer. Compared to bonding and forming a Li-Al alloy on the surface side of the Al layer, it is possible to further suppress deformation (curve etc.) of the negative electrode and the accompanying volume change of the battery and battery characteristic deterioration. It becomes.

On the other hand, when the base material layer is made of a metal selected from Cu, Ni, Ti and Fe or an alloy thereof, the deformation of the negative electrode due to the volume change when the Li-Al alloy is formed is suppressed. Since the action is further improved, not only in the case of bonding the Al layer on both sides of the base layer, but also in the case of bonding of the Al layer and formation of the Li-Al alloy on only one side of the base layer. It is possible to further suppress deformation (such as bending), and the volume change of the battery and the characteristic deterioration of the battery associated therewith.

In a laminate formed by bonding a laminated metal foil formed by bonding a base material layer and an Al layer with a Li foil, the surfaces of the Al layers on both sides of the base material layer (bonded to the base material layer Li foil is pasted to the other side).

Hereinafter, the case where the base material layer is Cu (Cu foil) and the case where the base material layer is Ni (Ni foil) will be described as an example, but the case where the base material layer is a material other than Cu or Ni The same is true.

Examples of the laminated metal foil formed by bonding a Cu layer and an Al layer include a clad material of a Cu foil and an Al foil, and a laminated film in which Al is vapor-deposited on a Cu foil to form an Al layer.

The Cu layer according to the laminated metal foil formed by joining the Cu layer and the Al layer includes a layer made of Cu (and unavoidable impurities), and contains Zr, Cr, Zn, Ni, Si, P, etc. as an alloy component. The layer etc. which consist of Cu alloy whose remainder is Cu and an unavoidable impurity (The content of the said alloy component is 10 mass% or less in total, preferably 1 mass% or less, for example) are mentioned.

In addition, as a laminated metal foil formed by joining a Ni layer and an Al layer, a clad material of Ni foil and Al foil, a laminated film in which Al is vapor-deposited on Ni foil to form an Al layer, etc. may be mentioned. .

As a Ni layer according to a laminated metal foil formed by joining a Ni layer and an Al layer, a layer composed of Ni (and unavoidable impurities) or an alloy component such as Zr, Cr, Zn, Cu, Fe, Si, P, etc. And the remaining portion is Ni and a Ni alloy which is an unavoidable impurity (the content of the alloy components is, for example, 20% by mass or less in total).

Furthermore, as an Al layer according to a laminated metal foil formed by joining a Cu layer and an Al layer or a laminated metal foil formed by joining a Ni layer and an Al layer, a layer made of Al (and an unavoidable impurity) or , Al alloy containing Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, Mo, etc. as alloy components, and the balance being Al and unavoidable impurities (the content of the alloy components is, for example, in total And the like.

In a laminated metal foil formed by joining a Cu layer and an Al layer, or in a laminated metal foil formed by joining a Ni layer and an Al layer, the ratio of the Li-Al alloy to be the negative electrode active material is made constant or more Therefore, when the thickness of the Cu layer or Ni layer which is the base material layer is 100, the thickness of the Al layer (but when the Al layer is joined to both the Cu layer or Ni layer which is the base layer) Is preferably 10 or more, more preferably 20 or more, still more preferably 50 or more, and particularly preferably 70 or more. In addition, in order to enhance the current collection effect and hold the Li-Al alloy sufficiently, a laminated metal foil formed by joining a Cu layer and an Al layer, or a laminated layer formed by joining a Ni layer and an Al layer. In the metal foil, the thickness of the Al layer is preferably 500 or less, more preferably 400 or less, and 300 or less, where the thickness of the Cu layer or Ni layer as the base material layer is 100. Is particularly preferred, and most preferably 200 or less.

The thickness of the Cu layer or the Ni layer as the base material layer is preferably 10 to 50 μm, and more preferably 40 μm or less. In addition, the thickness of the Al layer (however, in the case where the Al layer is bonded to both surfaces of the Cu layer and the Ni layer as the base layer, the thickness per side) is preferably 10 μm or more, and 20 μm or more The thickness is more preferably 30 μm or more, particularly preferably 150 μm or less, more preferably 70 μm or less, and particularly preferably 50 μm or less.

The thickness of the laminated metal foil formed by joining the Cu layer and the Al layer or the laminated metal foil formed by joining the Ni layer and the Al layer is 50 μm or more in order to set the capacity of the negative electrode at a certain level or more. Is preferably 60 μm or more, and is preferably 300 μm or less, more preferably 200 μm or less, in order to set the capacity ratio with the positive electrode active material in an appropriate range. Is particularly preferred.

The Li foil used for the negative electrode precursor is a foil made of Li (and unavoidable impurities), and alloy components such as Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, Mo, etc. in total 40 mass And foils composed of Li and Li alloy which is an unavoidable impurity, with the balance being contained in an amount of at most%.

In addition to the method of forming the Al active layer of the negative electrode using the above-described laminate formed by laminating Li foil on the surface of the laminated metal foil as a negative electrode precursor, as described above, as the second method, The Al active layer constituting the negative electrode can be formed also by a method of assembling a battery using the laminated metal foil as it is as a negative electrode precursor and charging the assembled battery.

That is, a Li—Al alloy is formed at least on the surface side by electrochemically reacting Al on at least the surface side of the Al metal layer of the laminated metal foil with Li ions in the non-aqueous electrolyte by charging the battery. It is also possible to use an Al active layer.

According to the second method using the laminated metal foil to which the Li foil is not bonded as a negative electrode precursor, the manufacturing process of the battery can be simplified. On the other hand, by forming the Al active layer using the laminated metal foil to which the Li foil is bonded as a negative electrode precursor, the irreversible capacity of the Li-Al alloy is offset by Li of the Li layer of the negative electrode precursor. In order to increase the capacity, it is preferable to form the negative electrode by the above-mentioned first method (to form the Al active layer of the negative electrode), and to use the negative electrode precursor according to the first method. The battery may be assembled and further charged to form a negative electrode (forming an Al active layer of the negative electrode).

In a battery having, as a negative electrode, a laminate including a metal base layer not alloyed with Li and an Al active layer bonded to the metal base layer as in the non-aqueous electrolyte battery of the present embodiment, From the viewpoint of securing excellent storage characteristics by maintaining the crystal structure of the substance acting as the negative electrode active material well to stabilize the potential of the negative electrode, the negative electrode is selected by any of the first method and the second method. Even if the Al active layer is formed, the battery is used in a range where the Li content is 48 atomic% or less, where the total of Li and Al in the Al active layer of the negative electrode is 100 atomic%. It is preferable to do. That is, it is preferable to stop charging when the content of Li in the Al active layer does not exceed 48 atomic% when charging the battery, and to stop charging when the content of Li is 40 atomic% or less Is more preferable, and it is particularly preferable to stop charging within the range of 35 atomic% or less.

The entire Al layer of the laminated metal foil may be alloyed with Li and act as an active material, but the base layer side of the Al layer is not alloyed with Li, and the Al active layer is the surface side It is more preferable to have a laminated structure of the Li—Al alloy layer and the Al layer remaining on the substrate side.

That is, by terminating charging in the above state, the separator side (positive electrode side) of the Al layer is reacted with Li to form a Li-Al alloy (mixed phase of α phase and β phase or β phase), On the other hand, it is assumed that the Al layer in the vicinity of the bonding portion with the base material layer remains as the original Al layer without being substantially reacted with Li, or the Li content becomes lower than that of the separator side. It is considered that excellent adhesion between the original Al layer and the base material layer can be maintained, and the Li-Al alloy formed on the separator side can be easily held on the base material layer. In particular, it is more preferable to stop charging in a state in which the Li-Al alloy formed on the separator side of the Al layer is mixed with the α phase.

In the present specification, “the original Al layer remains as it is without being substantially reacted with Li” means that the Al layer does not contain Li, and the Al layer contains several atomic% or less of Li. It refers to the fact that Al is maintained as it is in the state of the α phase, including the solid solution in the range.

In addition, in the non-aqueous electrolyte battery of the present embodiment, the content of Li when the total of Li and Al in the Al active layer of the negative electrode is 100 atomic% from the viewpoint of further enhancing the discharge capacity and the heavy load discharge characteristics. It is preferable to charge the battery to a range in which the amount is 15 atomic% or more, and more preferable to charge the battery to a range in which the amount is 20 atomic% or more.

Furthermore, it is desirable that the negative electrode according to the non-aqueous electrolyte battery of the present embodiment terminate the discharge in the state where the Al metal phase (α phase) and the Li—Al alloy phase (β phase) coexist. It is possible to suppress the volume change of the negative electrode at the time of charge and discharge, and to suppress the capacity deterioration at the charge and discharge cycle. In order to leave the β phase of the Li-Al alloy in the negative electrode, the content of Li at the end of discharge when the total of Li and Al in the negative electrode is 100 atomic%, should be about 3 atomic% or more. It is preferable that the content be 5 atomic% or more. On the other hand, in order to increase the discharge capacity, the Li content at the end of the discharge is preferably 12 atomic% or less, and more preferably 10 atomic% or less.

In the non-aqueous electrolyte battery of this embodiment, the negative electrode precursor used in the case of forming the negative electrode according to the first method in order to easily realize the usage condition of the battery as described above includes: When the thickness of the Al layer is 100, the thickness of the Li layer bonded to the Al layer is preferably 10 or more, more preferably 20 or more, and still more preferably 30 or more. And 80 or less are preferable, and 70 or less is more preferable.

The specific thickness of Li foil (when the laminate has Li foil on both sides, the thickness per side) is preferably 10 μm or more, more preferably 20 μm or more, and 30 μm The thickness is more preferably not less than 80 μm, and more preferably 70 μm or less.

Bonding of a Li foil and an Al layer (an Al foil for constituting the Al layer, or an Al layer related to a foil constituted by bonding a base layer constituting the negative electrode current collector and the Al layer) It can be carried out by a conventional method such as pressure bonding.

The laminate used as a negative electrode precursor used when forming a negative electrode by the first method is a foil obtained by bonding a Cu layer and an Al layer, or an Al layer of a foil obtained by bonding a Ni layer and an Al layer. , And Li foil can be manufactured together.

Next, the third method will be described. In the third method, a foil composed of Al can be used as a negative electrode precursor. The Al foil can be alloyed with a predetermined amount of Li beforehand, but similar to the second method, Al on the surface of the Al foil is charged into the non-aqueous electrolyte by charging after assembling the battery. It is also possible to electrochemically react with Li ion to convert it to a Li-Al alloy. Unlike the first method and the second method, in the third method, the step of previously bonding the Al metal layer and the metal base layer is unnecessary, and the production process is simplified. Is preferable.

The Al foil used in the third method includes a foil made of Al (and unavoidable impurities), and Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, Mo, etc. as alloy components, and the balance The foil etc. which consist of Al and Al alloy which is an unavoidable impurity (The content of the said alloy component is 50 mass% or less in total, for example) are mentioned. The thickness of the Al foil is preferably 40 μm or more, more preferably 50 μm or more, and preferably 300 μm or less in order to set the capacity ratio with the positive electrode active material in an appropriate range. Is more preferably 100 μm or less.

The Cu layer or Ni layer in the laminate used as the negative electrode precursor used in the first method and the second method for forming the negative electrode, and the Al foil used as the negative electrode precursor in the third method, The negative electrode lead can be provided according to a conventional method.

<Positive electrode>
The positive electrode according to the non-aqueous electrolyte battery of this embodiment has, for example, a structure having a positive electrode mixture layer containing a positive electrode active material, a conductive auxiliary agent, a binder and the like on one side or both sides of a current collector. it can. In addition, as the positive electrode active material, two or more types of positive electrode active materials containing a lithium-containing nickel layered oxide are used, and the positive electrode active material as a whole comprises Li, Ni, and a metal M other than Li and Ni. And the molar ratio Ni / (Ni + M) is 0 when the ratio of the total Ni amount to the total amount of the total Ni amount and the total amount of metal M is expressed as a molar ratio Ni / (Ni + M) in the total amount of the positive electrode active material. .5 or more and 0.9 or less. The metal M may be two or more metals.

In general, the positive electrode active material reacts with the non-aqueous electrolyte in a high temperature environment, a reaction product is deposited on the positive electrode, and a gas is simultaneously generated. When lithium cobaltate generally used for non-aqueous electrolyte batteries such as lithium ion secondary batteries is used as a positive electrode active material, the surface of lithium cobaltate reacts with the non-aqueous electrolyte under high temperature to make Co Although the reaction products contained are deposited on the surface of the positive electrode and simultaneously gas is generated, the reaction products containing Co are further decomposed and Co is eluted in the non-aqueous electrolyte. Then, the surface of lithium cobaltate and the non-aqueous electrolytic solution react again to generate a reaction product containing Co and generate gas. That is, if the positive electrode active material contains a large amount of lithium cobaltate, Co will continue to elute and gas will continue to be generated each time the battery is exposed to high temperatures.

However, two or more types of positive electrode active materials containing a lithium-containing nickel layered oxide are used, and the positive electrode active material contains Li, Ni, and a metal M other than Li and Ni as a whole. When the ratio of the total Ni amount to the total amount of the total Ni amount and the total amount of metal M is represented by the molar ratio Ni / (Ni + M) in the total amount of Ni, the molar ratio Ni / (Ni + M) is 0.5 or more and 0.9 In the following, the lithium-containing nickel layered oxide reacts with the non-aqueous electrolyte at a high temperature once to generate a reaction product containing Ni and generate gas, but the reaction product containing Ni is decomposed Instead, it remains on the positive electrode to form a film. Further, even if the battery is exposed to high temperature thereafter, the elution of Ni and the generation of gas are also suppressed. Therefore, metal elution hardly occurs even under high temperature with the battery charged. Therefore, even if the battery is stored under high temperature for a long time such as one month, gas generation can be suppressed, and a decrease in discharge capacity can also be suppressed.

The compositional analysis of the positive electrode active material can be performed as follows using an ICP (Inductive Coupled Plasma) method. First, 0.2 g of the positive electrode active material to be measured is collected and placed in a 100 mL container. Thereafter, 5 mL of pure water, 2 mL of aqua regia, and 10 mL of pure water are sequentially added, heated and dissolved, and after cooling, it is further diluted 25 times with pure water, and using an ICP analyzer “ICP-757” manufactured by JARRELASH, The composition is analyzed by the calibration method. The composition amount can be derived from the obtained result.

As the lithium-containing nickel layered oxide, it is preferable to use a composite oxide represented by the following general formula (1). The use of the complex oxide represented by the following general formula (1) can suppress the increase in resistance as well as suppress the gas generation during long-term storage.

Li _{1 + x} Ni _1-yz M ¹ _y M ² _z O ₂ (1)

In the general formula (1), M ¹ is at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Mo, Ti, Ba, W and Er, and M ² is Li, it is Ni and M ¹ other elements, is -0.1 ≦ x ≦ 0.1,0 ≦ y ≦ 0.5,0 ≦ z ≦ 0.05.

When Co is present in the crystal lattice in the complex oxide represented by the above general formula (1), the phase transition of the lithium-containing complex oxide by insertion and desorption of Li during charge and discharge of the non-aqueous electrolyte battery The irreversible reaction that occurs can be alleviated, and the reversibility of the crystal structure of the composite oxide can be enhanced, so that it is possible to construct a non-aqueous electrolyte battery with a longer charge and discharge cycle life.

When the complex oxide represented by the general formula (1) contains Mg, Mg ²⁺ rearranges to a Li site when phase rearrangement of the complex oxide occurs due to elimination and insertion of Li. Thus, the irreversible reaction is alleviated, and the reversibility of the layered crystal structure of the complex oxide represented as space group R3-m is improved.

When the complex oxide represented by the general formula (1) contains Mn, tetravalent Mn stabilizes unstable tetravalent Ni, and therefore non-aqueous electrolyte having a longer charge / discharge cycle life It becomes possible to construct an electrolyte battery.

When the complex oxide represented by the above general formula (1) contains W or Mo, the rate of expansion and contraction of crystals in charge and discharge due to this can be reduced, and charge and discharge cycle characteristics of the battery It leads to the improvement of

In the complex oxide represented by the above general formula (1), when Al is present in the crystal lattice, the crystal structure can be stabilized and its thermal stability can be improved, so that it is more safe It becomes possible to construct a high nonaqueous electrolyte battery. In addition, the presence of Al at the grain boundaries and surfaces of the particles of the composite oxide can suppress the temporal stability and side reactions with the non-aqueous electrolyte solution, and thus a longer-life non-aqueous electrolyte battery It is possible to configure

When Er is present at the grain boundary or surface of the particles of the composite oxide represented by the general formula (1), the catalytic property on the surface of the positive electrode active material can be reduced and the decomposition of the non-aqueous electrolyte can be suppressed. .

In the complex oxide represented by the general formula (1), when an alkaline earth metal element such as Ba is contained in the particles, the growth of primary particles is promoted and the crystallinity of the complex oxide is improved. The side reaction with the non-aqueous electrolytic solution is suppressed, and it becomes possible to configure a battery in which blistering is less likely to occur during high temperature storage.

In the complex oxide represented by the above general formula (1), when Ti is contained in the particles, it is arranged in a crystal defect such as oxygen deficiency in the LiNiO ₂ type crystal structure to stabilize the crystal structure. Therefore, the reversibility of the reaction of the composite oxide is enhanced, and a non-aqueous electrolyte battery having more excellent charge and discharge cycle characteristics can be configured.

When the complex oxide represented by the general formula (1) contains Zr, this is present at the grain boundaries and surfaces of the particles of the complex oxide, without impairing the electrochemical properties of the complex oxide. , Suppress its surface activity. In addition, the effect of suppressing the activity of the particle surface by Zr makes it possible to configure a non-aqueous electrolyte battery having excellent storage properties and long life.

In the complex oxide represented by the general formula (1), the element of M ¹ may or may not be contained according to the required characteristics of the respective elements described above. In order to secure the battery capacity, y representing the content of the element of M ¹ is preferably less than 0.5, and more preferably 0.3 or less.

The composite oxide represented by the general formula (1) may or may not contain M ² which is an element other than Li, Ni and M ¹ . The z representing the content of the element of M ² does not inhibit the effects of the present embodiment if it is 0.05 or less, and more preferably 0.01 or less.

The positive electrode active material may contain one type of the lithium-containing nickel layered oxide, or may contain two or more types.

Although two or more types of positive electrode active materials containing the lithium-containing nickel layered oxide are used as the positive electrode active material, lithium-containing composite oxidation different from the lithium-containing nickel layered oxide according to the required battery characteristics Can be included.

Examples of the lithium-containing composite oxide different from the lithium-containing nickel layered oxide include lithium cobalt oxides such as LiCoO ₂ ; lithium manganese oxides such as LiMnO ₂ and Li ₂ MnO ₃ ; LiMn ₂ O ₄ , Lithium-containing composite oxide of spinel structure such as Li _4/3 Ti _5/3 O ₄ ; lithium-containing composite oxide of olivine structure such as LiFePO ₄ ; these oxides as a basic composition, and some of their constituent elements Oxides substituted with other elements; and the like. These lithium-containing composite oxides may be used alone or in combination of two or more.

Even when the positive electrode active material contains a lithium-containing composite oxide different from the lithium-containing nickel layered oxide, the positive electrode active material contains 50% by mass or more of the lithium-containing nickel layered oxide. Is more preferable, and 80% by mass or more is more preferable. This is because the effects of the present embodiment described above can be favorably obtained.

When using the lithium-containing nickel layered oxide and the lithium-containing composite oxide different from the lithium-containing nickel layered oxide as the positive electrode active material, the total amount of Ni and the total amount of the positive electrode active material The molar ratio Ni / (Ni + M) of the total amount of Ni to the total amount of the total amount of metal M can be calculated by the following equation.

Ni / (Ni + M) = ΣN _j × a _j / (ΣN _j × a _j + ΣM _j × a _j )

Here, in the above formula, N _j is the molar composition ratio of Ni contained in the positive electrode active material j, a _j is the mixed mass ratio of the positive electrode active material j, and M _j is the molar composition ratio of M contained in the positive electrode active material j It is.

Examples of the conductive additive relating to the positive electrode mixture layer include carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black and the like; carbon materials such as carbon fibers and metal fibers Conductive fibers such as carbon fluoride; metal powders such as copper and nickel; organic conductive materials such as polyphenylene derivatives; and the like can be used.

Examples of the binder related to the positive electrode mixture layer include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethylcellulose (CMC), polyvinyl pyrrolidone (PVP) and the like.

The positive electrode contains, for example, a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder, dispersed in an organic solvent such as N-methyl-2-pyrrolidone (NMP) or water, , Etc.), the positive electrode mixture-containing paint is applied to one side or both sides of the current collector, dried, and may be subjected to a pressing process as necessary.

Alternatively, a formed body may be formed using the positive electrode mixture, and part or all of one surface of the formed body may be bonded to a positive electrode current collector to form a positive electrode. Bonding of the positive electrode mixture molded body and the positive electrode current collector can be performed by press treatment or the like.

As the current collector of the positive electrode, a foil of metal such as Al or Al alloy, a punching metal, a net, an expanded metal or the like may be used, but in general, an Al foil is suitably used. The thickness of the positive electrode current collector is preferably 10 to 30 μm.

The composition of the positive electrode mixture layer is, for example, 80.0 to 99.8% by mass of the positive electrode active material, 0.1 to 10% by mass of the conductive additive, and 0.1 to 10% by mass of the binder. Is preferred. The thickness of the positive electrode mixture layer is preferably 50 to 300 μm per side of the current collector.

The positive electrode lead body can be provided on the current collector of the positive electrode according to a conventional method.

The capacity ratio of the positive electrode to be combined with the negative electrode may be set such that the content of Li is 15 to 48 atomic% when the total of Li and Al in the negative electrode at the end of charging is 100 atomic%. It is desirable to set the capacity ratio of the positive electrode so that the β phase of the Li—Al alloy remains on the negative electrode at the end of the discharge.

<Separator>
The separator preferably has a property (that is, a shutdown function) that the pores are clogged at 80 ° C. or more (more preferably 100 ° C. or more) and 170 ° C. or less (more preferably 150 ° C. or less). A separator used in non-aqueous electrolyte batteries such as lithium ion secondary batteries can be used, for example, a microporous film made of polyolefin such as polyethylene (PE) or polypropylene (PP). The microporous membrane constituting the separator may be, for example, one using only PE or one using PP, or a laminate of a microporous membrane made of PE and a microporous membrane made of PP. It may be. The thickness of the separator is, for example, preferably 10 to 30 μm.

<Electrode body>
In the non-aqueous electrolyte battery of this embodiment, the positive electrode and the negative electrode are, for example, an electrode body formed by overlapping through a separator, a wound electrode body formed by further winding the electrode body in a spiral shape, or It is used in the form of a laminated electrode body in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked.

<Non-aqueous electrolyte>
For the non-aqueous electrolyte, a solution in which a lithium salt is dissolved in an organic solvent is used.

Examples of the organic solvent related to the non-aqueous electrolytic solution include cyclic carbonates such as ethylene carbonate, propylene carbonate (PC), butylene carbonate and vinylene carbonate; linear carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; methyl propionate Cyclic esters such as compounds having a lactone ring; linear ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme, tetraglyme; dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, etc. Cyclic ethers; nitriles such as acetonitrile, propionitrile and methoxypropionitrile; sulfites such as ethylene glycol sulfite; etc. The recited, it can also be used as a mixture of two or more. In order to obtain a battery with better characteristics, it is desirable to use a combination that can obtain high conductivity, such as a mixed solvent of a cyclic carbonate and the above-mentioned linear carbonate.

Further, it is more preferable to use PC as the organic solvent of the non-aqueous electrolytic solution. PC particularly contributes to securing the discharge characteristics of the non-aqueous electrolyte battery at low temperatures. For example, although ethylene carbonate is often used as the organic solvent of the non-aqueous electrolytic solution related to the non-aqueous electrolytic battery, since PC has a freezing point lower than ethylene carbonate, the battery output can be obtained even under a lower temperature environment. It is possible to improve the characteristics.

Furthermore, from the viewpoint of further improving the discharge characteristics at low temperature of the non-aqueous electrolyte battery, it is preferable to use a compound having a lactone ring together with PC as an organic solvent of the non-aqueous electrolyte.

Examples of the compound having a lactone ring include γ-butyrolactone and lactones having a substituent at the α position.

The lactones having a substituent at the α-position are preferably, for example, those of 5-membered rings (those having 4 carbon atoms in the ring). The number of substituents at the α-position of the lactones may be one or two.

Examples of the substituent include a hydrocarbon group, a halogen group (a fluoro group, a chloro group, a bromo group, an iodo group) and the like. As a hydrocarbon group, an alkyl group, an aryl group, etc. are preferable, and it is preferable that the carbon number is 1 or more and 15 or less (more preferably 6 or less). When the substituent is a hydrocarbon group, methyl, ethyl, propyl, butyl, phenyl and the like are more preferable.

Specific examples of lactones having a substituent at the α position are α-methyl-γ-butyrolactone, α-ethyl-γ-butyrolactone, α-propyl-γ-butyrolactone, α-butyl-γ-butyrolactone, α-phenyl -Γ-butyrolactone, α-fluoro-γ-butyrolactone, α-chloro-γ-butyrolactone, α-bromo-γ-butyrolactone, α-iodo-γ-butyrolactone, α, α-dimethyl-γ-butyrolactone, α, α -Diethyl-γ-butyrolactone, α, α-diphenyl-γ-butyrolactone, α-ethyl-α-methyl-γ-butyrolactone, α-methyl-α-phenyl-γ-butyrolactone, α, α-difluoro-γ-butyrolactone Α, α-Dichloro-γ-butyrolactone, α, α-Dibromo-γ-butyrolactone, α, α-Diiodo-γ-butyrola Tons, and the like, it may be used only one of these may be used in combination of two or more. Among these, α-methyl-γ-butyrolactone is more preferable.

The content of PC in the total organic solvent used for the non-aqueous electrolytic solution is preferably 10% by volume or more, and preferably 30% by volume or more, from the viewpoint of favorably securing the above-mentioned effects of the use. More preferable. As described above, since the organic solvent of the non-aqueous electrolytic solution may be only PC, the upper limit value of the preferable content of PC in all the organic solvents used for the non-aqueous electrolytic solution is 100% by volume.

When a compound having a lactone ring is used, the content of the compound having a lactone ring in the total organic solvent used for the non-aqueous electrolytic solution is 0.1 mass from the viewpoint of securing the effect by the use well. % Or more, and it is desirable to use this content in such a range that the preferred value is satisfied and the content of PC in the total organic solvent satisfies the above preferred value.

The lithium salt related to the non-aqueous electrolyte has high heat resistance and has the function of suppressing the corrosion of aluminum used in the battery in addition to the ability to enhance the storage characteristics of the non-aqueous electrolyte battery under high temperature environment. It is preferable to use LiBF ₄ because

Other lithium salts according to the non-aqueous electrolyte solution, for _{example, LiClO 4, LiPF 6, LiAsF} 6, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li 2 C 2 F 4 (SO 3) 2, LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC _n F _{2n + 1} SO ₃ (2 ≦ n ≦ 7), LiN (RfOSO ₂ ) ₂ [where, R f is a fluoroalkyl group], etc. Can be mentioned.

The concentration of the lithium salt in the non-aqueous electrolytic solution is preferably 0.6 mol / L or more, and more preferably 0.9 mol / L or more.

The concentration of all the lithium salts in the non-aqueous electrolytic solution is preferably 1.8 mol / L or less, more preferably 1.6 mol / L or less. Therefore, when only LiBF ₄ is used as the lithium salt, it is preferable to use it in a range where the concentration satisfies the above-mentioned preferred upper limit. On the other hand, when using other lithium salt with LiBF _4, while the concentration of LiBF ₄ satisfies preferable lower limit of the, it is preferably used in a range where the concentration of total lithium salt satisfies the preferred upper limit of the .

Further, it is preferable that the non-aqueous electrolytic solution contains a nitrile compound as an additive. By using a non-aqueous electrolyte to which a nitrile compound is added, the nitrile compound is adsorbed on the surface of the positive electrode active material to form a film, and this film suppresses gas generation due to oxidative decomposition of the non-aqueous electrolyte. In particular, the swelling of the battery when stored in a high temperature environment can be suppressed.

The nitrile compound to be added to the non-aqueous electrolytic solution includes mononitriles such as acetonitrile, propionitrile, butyronitrile, valeronitrile, benzonitrile, acrylonitrile and the like; malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1,4-dicyanoheptane 1,5-dicyanopentane (pimeronitrile), 1,6-dicyanohexane (suberonitrile), 1,7-dicyanoheptane (azelaonitrile), 2,6-dicyanoheptane, 1,8-dicyanooctane, 2,7-dicyano Dinitriles such as octane, 1,9-dicyanononane, 2,8-dicyanononane, 1,10-dicyanodecane, 1,6-dicyanodecane, 2,4-dimethylglutaronitrile; cyclic nitriles such as benzonitrile; methoxyaceto Tolyl alkoxy-substituted nitriles such as; include such is, may be used only one of these, or two or more may be used. Among these nitrile compounds, dinitrile is more preferable, and adiponitrile, pimeronitrile and suberonitrile are further preferable.

The content of the nitrile compound in the non-aqueous electrolyte used in the battery is preferably 0.1% by mass or more, and preferably 1% by mass or more, from the viewpoint of favorably securing the above-mentioned effects of the use. Is more preferred. However, when the amount of the nitrile compound in the non-aqueous electrolytic solution is too large, the discharge characteristics at low temperature of the battery tend to be deteriorated. Therefore, the content of the nitrile compound in the non-aqueous electrolyte used in the battery is from the viewpoint of making the discharge characteristics at a low temperature of the battery better by limiting the amount of the nitrile compound in the non-aqueous electrolyte to some extent. And 10% by mass or less, and more preferably 5% by mass or less.

The non-aqueous electrolytic solution preferably contains a phosphoric acid compound or a boric acid compound having a group represented by the following general formula (2) in the molecule.

In the general formula (2), X is Si, Ge or Sn, and R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or It represents an aryl group having 6 to 10 carbon atoms, and part or all of hydrogen atoms may be substituted with fluorine.

For example, batteries used for in-vehicle devices are not limited to high temperature environments, and may be used in cold regions. In a low temperature environment, the operability of the battery is reduced as compared with that at normal temperature, and in particular, the aged battery tends to have a reduced load characteristic. Therefore, it is preferable that high-load discharge can be performed even in a low temperature environment after being placed for a fixed time in a high temperature environment (for almost the same state as aging) assuming use at all temperatures.

In the non-aqueous electrolyte battery of the present embodiment, when a non-aqueous electrolyte containing a phosphoric acid compound or a boric acid compound having a group represented by the general formula (2) in the molecule is used, long-term operation at high temperature can be achieved. It is possible to enhance high load discharge characteristics in a low temperature environment after storage. Although the reason is not clear, the present inventors speculate as follows.

When a non-aqueous electrolytic solution containing a phosphoric acid compound or boric acid compound having a group represented by the general formula (2) in the molecule is used, the surface of the positive electrode active material mentioned above by the phosphoric acid compound or boric acid compound In order to form a strong coating with a low resistance, the coating is not broken even when the battery is stored under high temperature for a long time, so that the elution of metal from the positive electrode active material can be suppressed. In addition, since this film is unlikely to inhibit the insertion of Li ions even at low temperatures, it is possible to improve the heavy load discharge characteristics at low temperatures of the battery after long-term storage at high temperatures.

Furthermore, the above-mentioned phosphoric acid compound or boric acid compound also acts on the negative electrode of the non-aqueous electrolyte battery to form a film. The phosphoric acid compound or boric acid compound is considered to reduce the amount of Li used when a film is formed on the negative electrode surface, and form a thin and good film on the negative electrode surface. As a result, the coating on the surface of the negative electrode is not broken even when stored at high temperatures for a long time, so that the deterioration of the negative electrode can be suppressed. Moreover, this film is difficult to inhibit the desorption of Li ions even at low temperatures. Also for these reasons, it is possible to improve the heavy load discharge characteristics at low temperature after storage for a long time at high temperature.

As described above, by combining the specific positive electrode and the specific negative electrode according to the present embodiment with the non-aqueous electrolytic solution containing the phosphoric acid compound or the boric acid compound, the above-described respective functions function synergistically. Thus, the battery can have better storage characteristics in a high temperature environment and can cope with temperature changes.

In the general formula (2), X is Si, Ge or Sn, preferably Si. That is, the phosphoric acid compound is more preferably a phosphoric acid silyl ester, and the boric acid compound is more preferably a boric acid silyl ester. In the general formula (2), R ¹ , R ² and R ³ each independently represent an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms However, methyl or ethyl is more preferred. And as a group represented by the said General formula (2), a trimethylsilyl group is especially preferable.

Moreover, in the said phosphoric acid compound, only one of the hydrogen atoms which phosphoric acid has may be substituted by the group represented by the said General formula (2), Among the hydrogen atoms which phosphoric acid has, Two may be substituted by the group represented by the said General formula (2), and all three of the hydrogen atoms which phosphoric acid has may be substituted by the group represented by the said General formula (2) More preferably, all three of the hydrogen atoms of phosphoric acid are substituted with the group represented by the general formula (2).

As such a phosphoric acid compound, tris (trimethylsilyl) phosphate is mentioned as a particularly preferable one.

Further, in the boric acid compound, only one of hydrogen atoms contained in boric acid may be substituted with a group represented by the general formula (2), and among hydrogen atoms contained in boric acid, Two may be substituted by the group represented by the said General formula (2), and all three of the hydrogen atoms which boric acid has may be substituted by the group represented by the said General formula (2) More preferably, all three of the hydrogen atoms of boric acid are substituted with a group represented by the general formula (2).

As such a boric acid compound, tris (trimethylsilyl) borate is mentioned as a particularly preferable one.

The content of the phosphoric acid compound or boric acid compound having the group represented by the general formula (2) in the molecule in the non-aqueous electrolyte used in the battery better secures the above-mentioned effect by its use It is preferable that it is 0.2 mass% or more from a viewpoint of carrying out, and it is more preferable that it is 0.5 mass% or more. Moreover, if the content is too large, the gas generated at the time of film formation will increase, and thus the phosphoric acid having in its molecule the group represented by the above general formula (2) in the non-aqueous electrolyte used in the battery. The content of the compound or boric acid compound is preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

In the non-aqueous electrolyte battery, in addition to the above-mentioned phosphoric acid compound or boric acid compound, non-aqueous electrolysis containing LiBF ₄ as a lithium salt, containing PC as an organic solvent, and further containing a nitrile compound It is particularly preferred to use a solution. When such non-aqueous electrolyte is used, the action of each of the components acts synergistically to suppress battery swelling at high temperature storage to a higher degree, and also to a low temperature environment after high temperature storage (for example, The discharge characteristics at −20 ° C. or less can be further enhanced.

In addition, vinylene carbonates, 1,3-propanesultone, diphenyldisulfide, cyclohexylbenzene, biphenyl, fluorobenzene, t-butylbenzene and the like for the purpose of further improving various battery characteristics to these non-aqueous electrolytes. Additives can also be added as appropriate. Furthermore, the non-aqueous electrolytic solution may be gelled (gelled electrolyte) using a gelling agent such as a known polymer.

<Non-aqueous electrolyte battery>
In the non-aqueous electrolyte battery of this embodiment, for example, after the electrode body is loaded into the outer package, the non-aqueous electrolyte is injected into the outer package, and the electrode body is immersed in the non-aqueous electrolyte. It is manufactured by sealing the opening of. As the exterior body, an exterior can made of steel, aluminum, or an aluminum alloy, an exterior body formed of a laminated film formed by vapor deposition of metal, or the like can be used.

Since the non-aqueous electrolyte battery of the present embodiment is configured to regulate the positive electrode capacity, it is possible to detect the charge end timing by controlling the charge amount, controlling the charge voltage, etc. It is possible to set a charge termination condition.

The assembled battery is preferably subjected to an aging treatment at a relatively high temperature (for example, 60 ° C.) in a fully charged state. Since the formation of the Li—Al alloy in the negative electrode proceeds by the above-mentioned aging treatment, the discharge capacity and load characteristics of the battery are further improved.

Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
A 25 mm × 40 mm clad material (laminated metal foil) in which an Al foil of 30 μm thickness was laminated on both sides of a 30 μm thick Ni foil was used as a negative electrode precursor. A Cu foil for current collection was ultrasonically welded to the end of the clad material, and then an ultrasonic weld of a Ni tab for conductive connection with the outside of the battery was ultrasonically welded to the end of the Cu foil. Used for

On the other hand, the positive electrode was produced as follows. First, a lithium-containing nickel layered oxide LiNi _0.92 Co _0.04 Mn _0.02 Al _0.01 Mg _0.01 O ₂ 92.2 parts by mass, another lithium-containing composite oxide LiCoO ₂ : 4.8 parts by mass, and conductivity A positive electrode mixture-containing slurry was prepared by dispersing 1.5 parts by mass of acetylene black as an auxiliary agent and 1.5 parts by mass of PVDF as a binder in NMP. Next, this positive electrode mixture-containing slurry is applied to one side of a 12 μm-thick Al foil, dried, and subjected to press treatment to form a positive electrode combination having a mass of approximately 17 mg / cm ^{2 on} one side of the Al foil current collector. The agent layer was formed. The positive electrode mixture layer was not formed on a part of the application surface of the slurry, and a part where the Al foil was exposed was provided. Then, the Al foil current collector is cut into a size of 20 mm × 45 mm, and the current collector is subjected to ultrasonic welding of an Al tab for conductive connection with the outside of the battery at a location where the Al foil is exposed. A positive electrode having a positive electrode mixture layer of 20 mm × 30 mm in size on one side of

Next, the positive electrodes were respectively laminated on both sides of the negative electrode precursor with the Ni tab welded, via a separator made of a microporous film made of PE and having a thickness of 16 μm, to produce a set of electrode bodies. In addition, LiBF ₄ is dissolved at a concentration of 1 mol / L in a mixed solvent of propylene carbonate (PC) and ethyl methyl carbonate (EMC) at a volume ratio of 1: 2, and adiponitrile is further added in an amount of 3% by mass. Thus, a non-aqueous electrolyte was prepared. The electrode body is dried at 60 ° C. in vacuum for 15 hours, and then enclosed in a laminate film outer package together with the non-aqueous electrolytic solution, so that it has an external appearance shown in FIG. A non-aqueous electrolyte battery having a cross-sectional structure shown in 3 was produced.

Here, FIG. 2 and FIG. 3 will be described. FIG. 2 is a plan view schematically showing the non-aqueous electrolyte battery of this embodiment, and FIG. 3 is a cross-sectional view taken along line II of FIG. The non-aqueous electrolyte battery 1 includes a laminated electrode body in which a positive electrode 5 and a negative electrode 6 are laminated via a separator 7 in a laminate film outer package 2 made of two sheets of laminate films, and a non-aqueous electrolyte (Not shown), and the laminate film sheath 2 is sealed by heat-sealing the upper and lower laminate films at the outer peripheral portion thereof. In FIG. 3, in order to avoid that a drawing becomes complicated, each layer which comprises the laminate film exterior body 2, and each layer of the positive electrode 5 and the negative electrode 6 are not distinguished and shown.

The positive electrode 5 is connected to the positive electrode external terminal 3 via the lead body in the battery 1, and although not shown, the negative electrode 6 is also connected to the negative electrode external terminal 4 via the lead body in the battery 1 doing. One end of the positive electrode external terminal 3 and the negative electrode external terminal 4 is drawn to the outside of the laminate film outer package 2 so as to be connectable to an external device or the like.

(Example 2)
Lithium nickel-containing layered oxide LiNi _0.90 Co _0.05 Mn _0.025 Al _0.01 Mg _0.01 Ba _0.005 O ₂ : 87.3 parts by mass, and another lithium-containing composite oxide LiCoO ₂ : 9.7 parts by mass A positive electrode was produced in the same manner as in Example 1 except for the above, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 3)
Use 87.3 parts by mass of LiNi _0.85 Co _0.10 Mn _0.025 Al _0.01 Mg _0.01 Ba _0.005 O ₂ which is a lithium-containing nickel layered oxide and 9.7 parts by mass of another lithium-containing composite oxide LiCoO ₂ A positive electrode was produced in the same manner as in Example 1 except for the above, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 4)
Example 1 except that lithium nickel-containing layered oxide LiNi _0.80 Co _0.15 Al _0.05 O ₂ : 87.3 parts by mass and other lithium-containing composite oxide LiCoO ₂ : 9.7 parts by mass A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 5)
Example 1 except using LiNi _0.70 Co _0.20 Mn _0.10 O ₂ : 87.3 parts by mass which is a lithium-containing nickel layered oxide and 9.7 parts by mass of another lithium-containing composite oxide LiCoO ₂ A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 6)
Example 1 except using LiNi _0.60 Co _0.20 Mn _0.20 O ₂ : 87.3 parts by mass which is a lithium-containing nickel layered oxide and 9.7 parts by mass of another lithium-containing composite oxide LiCoO ₂ A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 7)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 8)
Lithium nickel-containing layered oxide LiNi _0.85 Co _0.10 Mn _0.025 Al _0.01 Mg _0.01 Ba _0.005 O ₂ : 58.2 parts by mass, and another lithium-containing composite oxide LiCoO ₂ : 38.8 parts by mass A positive electrode was produced in the same manner as in Example 1 except for the above, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 9)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode is prepared in the same manner as in Example 1. A non-aqueous electrolyte is prepared in the same manner as in Example 1 except that tris (trimethylsilyl) phosphate is added in an amount of 3% by mass, and the positive electrode and the non-aqueous electrolyte are prepared. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that it was used.

(Example 10)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode is prepared in the same manner as in Example 1. A non-aqueous electrolyte is prepared in the same manner as in Example 1 except that tris (trimethylsilyl) phosphate is added in an amount of 0.5% by mass. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the solution was used.

(Example 11)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode is prepared in the same manner as in Example 1. A non-aqueous electrolyte is prepared in the same manner as in Example 1 except that tris (trimethylsilyl) phosphate is added in an amount of 5% by mass, and the positive electrode and the non-aqueous electrolyte are prepared. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that it was used.

(Example 12)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode was prepared in the same manner as in Example 1. A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that tris (trimethylsilyl) borate was added in an amount of 3% by mass, and the positive electrode and the non-aqueous electrolyte were prepared. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that it was used.

(Example 13)
Except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide and 19.4 parts by mass of carbon coated LiFePO ₄ which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in Example 1, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 14)
Implementation except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide and 19.4 parts by mass of LiMn ₂ O ₄ which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in Example 1, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 15)
77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of another lithium-containing composite oxide LiNi _0.33 Co _0.33 Mn _0.33 O ₂ A positive electrode was produced in the same manner as in Example 1 except for the above, and a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 16)
A non-aqueous electrolyte battery was produced in the same manner as in Example 7 except that an Al foil having a thickness of 25 μm and a size of 25 mm × 40 mm was used as the negative electrode precursor.

(Example 17)
A non-aqueous electrolyte battery was produced in the same manner as Example 9, except that an Al foil having a thickness of 25 μm and a size of 25 mm × 40 mm was used as the negative electrode precursor.

(Example 18)
As a negative electrode precursor, an Al foil having a thickness of 75 μm and a size of 25 mm × 40 mm was used. In addition, LiNi _0.80 Co _0.10 Mn _0.10 O ₂ : 77.6 parts by mass which is a lithium-containing nickel layered oxide, and LiNi _0.33 Co _0.33 Mn _0.33 O ₂ : 19.4 parts by mass which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in Example 1 except for using. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this negative electrode precursor and this positive electrode were used.

(Comparative example 1)
Example 1 except that LiNi _0.33 Co _0.33 Mn _0.33 O ₂ : 87.3 parts by mass which is a lithium-containing nickel layered oxide and 9.7 parts by mass of another lithium-containing composite oxide LiCoO ₂ are used. A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Comparative example 2)
Example 1 except using 77.6 parts by mass of LiNi _0.33 Co _0.33 Mn _0.33 O ₂ which is a lithium-containing nickel layered oxide and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Comparative example 3)
Example 1 except using 77.6 parts by mass of LiNi _0.33 Co _0.33 Mn _0.33 O ₂ which is a lithium-containing nickel layered oxide and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide In the same manner as in Example 1 except that a positive electrode was prepared and tris (trimethylsilyl) phosphate was added in an amount of 3% by mass, a non-aqueous electrolytic solution was prepared in the same manner as in Example 1, and this positive electrode and non-aqueous electrolytic solution were used. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except for the above.

(Comparative example 4)
Example 1 except using 77.6 parts by mass of LiNi _0.80 Co _0.15 Al _0.05 O ₂ which is a lithium-containing nickel layered oxide, and 19.4 parts by mass of LiCoO ₂ which is another lithium-containing composite oxide A positive electrode was produced in the same manner as in the above.

Moreover, the negative electrode was produced as follows. First, 97.5 parts by mass of natural graphite having a number average particle diameter of 10 μm which is a negative electrode active material, 1.5 parts by mass of styrene butadiene rubber which is a binder, and 1 part by mass of carboxymethyl cellulose which is a thickener Then, water was added and mixed to prepare a negative electrode mixture-containing paste. Next, this negative electrode mixture-containing paste is applied to one side of a Cu foil having a thickness of 8 μm, dried, and subjected to press treatment to give a mass of approximately 9.7 mg / cm ^{2 on} one side of the Cu foil current collector. A negative electrode mixture layer was formed. The negative electrode mixture layer was not formed on a part of the application surface of the negative electrode mixture-containing paste, and a portion where the Cu foil was exposed was provided. Then, the Cu foil current collector is cut into a size of 20 mm × 45 mm, and the current collector is ultrasonically welded to a location where the Cu foil is exposed, for a conductive connection with the outside of the battery. A negative electrode having a negative electrode mixture layer of 20 mm × 30 mm in size on one side of

A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode produced above were used.

(Comparative example 5)
As a negative electrode precursor, an Al foil having a thickness of 75 μm and a size of 25 mm × 40 mm was used. _{Further, LiNi 0.33 Co 0.33 Mn 0.33 O} 2 is a lithium-containing nickel layered oxide: 77.6 parts by mass, LiCoO as other lithium-containing complex oxide _2: the embodiment except for using a 19.4 parts by weight A positive electrode was produced in the same manner as in Example 1. A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this negative electrode precursor and this positive electrode were used.

Tables 1, 2 and 3 show the configurations of the non-aqueous electrolyte batteries of Examples 1 to 18 and Comparative Examples 1 to 5.

The following high-temperature storage characteristics 1, high-temperature storage characteristics 2 and high-temperature storage characteristics 3 of the non-aqueous electrolyte batteries of Examples 1 to 15 and Comparative Examples 1 to 4 were evaluated.

<High temperature storage characteristic 1>
About each battery of an example and a comparative example, constant current (6 mA) -constant voltage (4.0 V) charge was performed, and charge was stopped when charge current fell to 0.3 mA. Furthermore, the battery was fully charged by charging under the above-mentioned charging conditions. Each fully charged battery was hung with a thin silk thread, immersed in pure water until the battery was completely submerged, and the weight in water was measured. Next, each fully charged battery is stored at 85 ° C. for 10 days and cooled to room temperature, and then the weight in water is measured in the same manner as above, and the difference from the weight before storage The volume difference of the battery before and after storage was calculated, and this volume difference was regarded as the volume change 1 of the battery.

<High temperature storage characteristic 2>
The batteries were fully charged in the same manner as the method described above for each of the batteries of the Examples and Comparative Examples (a battery different from the battery stored for 10 days). Each fully charged battery was hung with a thin silk thread, immersed in pure water until the battery was completely submerged, and the weight in water was measured. Next, each fully charged battery is stored at 85 ° C. for 30 days and cooled to room temperature, and then the weight in water is measured in the same manner as above, and the difference from the weight before storage The volume difference of the battery before and after storage was calculated, and this volume difference was defined as the volume change 2 of the battery.

<High temperature storage characteristic 3 (low temperature discharge characteristics after high temperature storage)>
The batteries were fully charged in the same manner as described above for the batteries of the Examples and Comparative Examples (the batteries other than the batteries stored for 10 days and stored for 30 days). After storing each fully charged battery at 85 ° C. for 10 days, the battery is discharged to 2.0 V at a constant current of 45 mA under an environment of −20 ° C. It was measured.

The evaluation results of the high temperature storage characteristic 1, the high temperature storage characteristic 2 and the high temperature storage characteristic 3 of Examples 1 to 15 and Comparative Examples 1 to 4 are shown in Table 4.

Further, evaluation results of the high temperature storage characteristic 1, the high temperature storage characteristic 2 and the high temperature storage characteristic 3 of Examples 16 to 18 and Comparative Example 5 are shown in Table 5.

From Table 4, in the batteries of Examples 1 to 15, the volume change 1 after 10 days of high temperature storage and the volume change 2 of 30 days after high temperature storage are all less than 1.1 cm ^3, and the low temperature after 10 days of high temperature storage It can be seen that all the discharge times are 3 minutes or more, and the high temperature storage characteristics are excellent.

Further, in the batteries of Examples 9 to 12 in which tris (trimethylsilyl) phosphate or tris (trimethylsilyl) borate was added to the non-aqueous electrolytic solution, the low temperature discharge time after 10 days of high temperature storage was 13 minutes or more in all cases. It can be seen that the later low temperature discharge characteristics are particularly excellent.

On the other hand, in the batteries of Comparative Examples 1 to 3 in which the molar ratio Ni / (Ni + M) is out of the range of 0.5 to 0.9, the volume change 2 after 30 days of high temperature storage is all 1.1 cm ³ It becomes above, and it turns out that gas generation of a battery became large. In the battery of Comparative Example 4 using a graphite negative electrode, the volume change 2 after 30 days of high temperature storage is 1.5 cm ³ or more, and the low temperature discharge time after 10 days of high temperature storage is 0.5 minutes or less, It can be seen that the storage characteristics are greatly inferior.

Furthermore, it is understood from Table 5 that even when Al foil is used as the negative electrode precursor, the use of the positive electrode active material according to the present embodiment has the effect of improving the high temperature storage characteristics.

The present invention can be practiced as other embodiments without departing from the scope of the present invention. The embodiments disclosed in the present application are an example, and the present invention is not limited thereto. The scope of the present invention is interpreted with priority given to the description of the attached claims rather than the description of the specification above, and all the modifications within the scope equivalent to the claims fall within the scope of the claims. It is included.

Since the non-aqueous electrolyte battery of the present invention has good storage characteristics under high temperature environment, taking advantage of these characteristics, good capacity over a long period of time under high temperature environment like power source application of automotive equipment It can be preferably applied to applications requiring maintainability.

Reference Signs List 1 non-aqueous electrolyte battery 2 laminate film outer package 5 positive electrode 6 negative electrode 7 separator 100 negative electrode precursor 101 laminated metal foil 101 a metal base layer 101 b Al metal layer 102 Li foil

Claims (13)

A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, comprising:
The positive electrode includes at least two or more types of positive electrode active materials,
At least one of the positive electrode active materials comprises a lithium-containing nickel layered oxide,
The positive electrode active material generally includes Li, Ni, and a metal M other than Li and Ni,
The molar ratio Ni / (Ni + M) is 0.5 or more when the ratio of the total Ni amount to the total amount of the total Ni amount and the total amount of metal M is expressed as molar ratio Ni / (Ni + M) in the total amount of the positive electrode active material. 0.9 or less,
The negative electrode includes an Al active layer,
A Li-Al alloy is formed on the surface side of the Al active layer,
The non-aqueous electrolyte battery is characterized in that the non-aqueous electrolyte contains a lithium salt and an organic solvent. The non-aqueous electrolyte battery according to claim 1, wherein the lithium-containing nickel layered oxide is represented by the following general formula (1).
Li _{1 + x} Ni _1-yz M ¹ _y M ² _z O ₂ (1)
In the general formula (1), M ¹ is at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Mo, Ti, Ba, W and Er, and M ² is Li, it is Ni and M ¹ other elements, is -0.1 ≦ x ≦ 0.1,0 ≦ y ≦ 0.5,0 ≦ z ≦ 0.05. The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode active material contains a lithium-containing composite oxide different from the lithium-containing nickel layered oxide. The non-aqueous electrolyte battery according to any one of claims 1 to 3, wherein the positive electrode active material contains 50% by mass or more of the lithium-containing nickel layered oxide. The negative electrode includes a metal base layer not alloyed with Li, and the Al active layer bonded to the metal base layer,
The non-aqueous electrolyte battery according to any one of claims 1 to 4, wherein a Li-Al alloy is formed on the surface side of the Al active layer. The non-aqueous electrolyte battery according to claim 5, wherein the metal base layer not alloyed with Li is composed of a metal selected from the group consisting of Cu, Ni, Ti and Fe or an alloy thereof. The thickness of the said metal base layer is 10 micrometers or more and 50 micrometers or less, The non-aqueous electrolyte battery of Claim 5 or 6. The non-aqueous electrolyte according to any one of claims 1 to 7, wherein the non-aqueous electrolyte further contains a phosphoric acid compound or a boric acid compound having a group represented by the following general formula (2) in the molecule. battery.

In the general formula (2), X is Si, Ge or Sn, and R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms or It represents an aryl group having 6 to 10 carbon atoms, and part or all of hydrogen atoms may be substituted with fluorine. The non-aqueous electrolyte battery according to claim 8, wherein the non-aqueous electrolyte contains tris (trimethylsilyl) phosphate as a phosphoric acid compound having a group represented by the general formula (2) in the molecule. The non-aqueous electrolyte battery according to claim 8, wherein the non-aqueous electrolyte contains tris (trimethylsilyl) borate as a boric acid compound having a group represented by the general formula (2) in a molecule. The non-aqueous electrolyte battery according to any one of claims 1 to 10, wherein the non-aqueous electrolyte contains LiBF ₄ as the lithium salt, contains propylene carbonate as the organic solvent, and further contains a nitrile compound. The non-aqueous electrolyte battery according to claim 11, wherein the non-aqueous electrolyte contains, as the nitrile compound, at least one selected from the group consisting of suberonitrile, pimeronitrile and adiponitrile. The non-aqueous electrolyte battery according to claim 11, wherein a content of the nitrile compound in the non-aqueous electrolyte is 0.1% by mass or more and 10% by mass or less.

Images