JP2019207755A - Nonaqueous electrolyte battery and manufacturing method therefor - Google Patents

Abstract

To provide a nonaqueous electrolyte battery having high long-term reliability under a high temperature environment.SOLUTION: A nonaqueous electrolyte battery comprises a positive electrode, a negative electrode 200, nonaqueous electrolyte, and a separator. The positive electrode includes a positive electrode collector and a positive electrode mixture layer formed on the positive electrode collector. The positive electrode mixture layer can occlude/release Li ions. The negative electrode 200 has area larger than that of the positive electrode mixture layer of the positive electrode and is disposed so as to cover the whole surface of the positive electrode mixture layer via the separator. The negative electrode 200 includes an Al layer 201 and a Li-Al alloy layer 202 formed on a surface of the Al layer 201. The tensile strength of the negative electrode 200 is equal to or greater than 4 N/mm.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a nonaqueous electrolyte battery having good high-temperature storage characteristics and a method for producing the same.

  Non-aqueous electrolyte batteries are used for various applications by taking advantage of characteristics 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 for in-vehicle electronic devices, the non-aqueous electrolyte has better storage characteristics than a non-aqueous electrolyte secondary battery, which is widely used, and has almost no decrease in capacity even when stored for a long period of several years or more. An electrolyte primary battery is used.

  As the negative electrode active material of the non-aqueous electrolyte primary battery, metallic lithium or a lithium alloy such as a Li—Al (lithium-aluminum) alloy is used. In the non-aqueous electrolyte secondary battery, the negative electrode active material is used. Since a lithium alloy can be used as a material, battery characteristics can be stabilized by forming a negative electrode using a clad material of a metal that can occlude and release lithium and a dissimilar metal that does not occlude and release lithium. Has also been proposed (Patent Documents 1 and 2).

  In addition, for the purpose of enhancing the storage characteristics in a high temperature environment that can be repeatedly charged, a laminate containing a metal base layer that is not alloyed with Li and an Al active layer on both sides of the metal base layer. A non-aqueous electrolyte battery using a clad material having a Li-Al alloy on the surface side of an Al active layer as a negative electrode has been proposed (Patent Document 3).

JP-A-8-293302 Japanese Patent Laid-Open No. 10-106628 International Publication No. 2016/039323

  On the other hand, in the non-aqueous electrolyte battery disclosed in Patent Document 3 using a clad material as a negative electrode, it is possible to repeatedly charge and improve storage characteristics in a high temperature environment, but the clad material is expensive, Further, when the battery is in an overdischarged state, the metal constituting the metal base layer of the clad material is eluted into the non-aqueous electrolyte solution, which has a problem that the battery characteristics are adversely affected.

  In order to cope with this problem, it is conceivable to use an inexpensive aluminum plate instead of an expensive clad material for the negative electrode as partially disclosed in Patent Document 2. However, when only an aluminum plate is used for the negative electrode, when it is excessively charged, Al and Li react too much, and the thickness of the Li-Al alloy layer formed on both sides of the aluminum plate gradually increases. At the same time, the thickness of the aluminum plate (Al layer) gradually decreases, and the negative electrode itself also expands due to the formation of the Li—Al alloy layer, so that the Al layer eventually cannot withstand the stress due to the expansion of the negative electrode. It is expected that the battery will be broken and the reliability of the battery in a high temperature environment is lowered. In particular, in the case of a rectangular battery in which a wound electrode body is enclosed in a rectangular outer casing as compared with the cylindrical battery disclosed in Cited Document 2, since a large stress is applied to the R portion of the negative electrode, the reliability of the battery is reduced. Is more concerned.

  The present invention solves the above problems, and provides a non-aqueous electrolyte battery that can maintain the strength of the negative electrode even when aluminum is used alone as a negative electrode material and has high long-term reliability in a high-temperature environment. is there.

  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, wherein the positive electrode is formed on the positive electrode current collector and the positive electrode current collector. The positive electrode mixture layer is capable of inserting and extracting Li ions, the area of the negative electrode is larger than the area of the positive electrode mixture layer of the positive electrode, and the negative electrode Is arranged so as to cover the entire surface of the positive electrode mixture layer with the separator interposed therebetween, and the negative electrode includes an Al layer and a Li-Al alloy layer formed on the surface of the Al layer, The tensile strength is 4 N / mm or more.

The nonaqueous electrolyte battery manufacturing method of the present invention is a method for manufacturing the nonaqueous electrolyte battery of the present invention, wherein a positive electrode mixture layer is formed on at least one surface of the positive electrode current collector, and A step of preparing a positive electrode having a capacity of 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less, a larger area than the area of the positive electrode mixture layer of the positive electrode, and a thickness of 30 μm or more A step of preparing a negative electrode precursor made of an aluminum base material of 150 μm or less, and the negative electrode precursor are arranged so as to cover the entire surface of the positive electrode mixture layer of the positive electrode through a separator to produce an electrode body. And a step of charging the electrode body and the non-aqueous electrolyte solution after enclosing them in an exterior body.

  ADVANTAGE OF THE INVENTION According to this invention, the nonaqueous electrolyte battery with high long-term reliability in a high temperature environment can be provided.

FIG. 1 is a schematic cross-sectional view of an aluminum substrate used for a negative electrode precursor. FIG. 2 is a schematic cross-sectional view of the negative electrode after initial charging. FIG. 3 is a perspective view schematically showing the nonaqueous electrolyte battery of the example. 4 is a cross-sectional view taken along the line II of FIG.

  An embodiment of a nonaqueous electrolyte battery disclosed in the present application will be described. The non-aqueous electrolyte battery according to the present embodiment includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator. The positive electrode includes a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector. The positive electrode mixture layer can occlude and release Li ions, the area of the negative electrode is larger than the area of the positive electrode mixture layer of the positive electrode, and the negative electrode passes through the separator The negative electrode includes an Al layer and a Li-Al alloy layer formed on the surface of the Al layer, and the negative electrode has a tensile strength of 4 N / mm. That's it.

  The non-aqueous electrolyte battery of this embodiment can improve long-term reliability in a high-temperature environment by setting it as the said structure.

  Li (metal Li) and Li—Al alloys (alloys of Li and Al) have lower acceptability of Li (Li ions) than carbon materials, and non-aqueous electrolytes using this as a negative electrode active material In the secondary battery, when charging and discharging are repeated, the capacity tends to decrease at an early stage. For these reasons, carbon materials such as graphite are widely used as negative electrode active materials in conventional non-aqueous electrolyte secondary batteries that are expected to be repeatedly charged and discharged.

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

  For this reason, batteries used for in-vehicle equipment and outdoor equipment have better storage characteristics than conventional non-aqueous electrolyte secondary batteries, and even when stored for a long period of several years or more, there is almost no decrease in capacity. There is no non-aqueous electrolyte primary battery applied.

  On the other hand, even in such applications, for reasons such as ease of maintenance, charging does not require repeated charging and discharging as many times as in ordinary secondary batteries, but charging can be performed several times to several tens of times. There is a request for application of possible batteries.

  Therefore, the nonaqueous electrolyte battery of the present embodiment can achieve high storage characteristics and high capacity even when used in a high temperature environment such as in-vehicle or outdoor equipment. Therefore, it was decided to use a Li—Al alloy formed on the surface of the Al layer as the negative electrode active material so that the battery can be charged a certain number of times.

  When aluminum is used for the negative electrode material, the negative electrode precursor is composed of aluminum foil or the like, and the negative electrode precursor and the positive electrode, separator, non-aqueous electrolyte, etc. are stored in the battery, and then the initial charge (chemical conversion) is performed. ) To electrochemically react the aluminum foil and Li ions in the non-aqueous electrolyte to form a Li-Al alloy on the surface of the aluminum foil, and to form an Al layer and the surface of the Al layer. A negative electrode provided with the prepared Li—Al alloy layer is formed and used. If an Li-Al alloy is formed on the surface of the aluminum foil without limitation during this initial charge, the Al layer that becomes the core material of the negative electrode becomes too thin and the strength decreases. In the worst case, all the aluminum foil is Li It may be considered that the alloy becomes an Al alloy, the core material of the negative electrode disappears, and the strength of the negative electrode is extremely reduced. Therefore, in this embodiment, in order to maintain the strength of the negative electrode and ensure the reliability of the battery, the tensile strength of the negative electrode is set to 4 N / mm or more. Making the tensile strength of the negative electrode 4 N / mm or more substantially means maintaining the strength by maintaining the thickness of the Al layer serving as the core material of the negative electrode at a certain level or more.

  Hereinafter, each component of the nonaqueous electrolyte battery of this embodiment will be described.

<Negative electrode>
In forming the negative electrode according to the non-aqueous electrolyte battery of the present embodiment, only the Al base material (Al foil or the like) is used as the negative electrode precursor without using the current collector. Specifically, the negative electrode precursor made of the Al base material is used for assembling the battery as it is, and the Al base material electrochemically reacts with Li ions in the non-aqueous electrolyte by charging after the assembly. Thus, a negative electrode having an Al layer and a Li—Al alloy layer formed on the surface of the Al layer is formed.

  Since the negative electrode always has an Al layer having a certain thickness, the Al layer serves as a core material of the negative electrode, and the tensile strength of the negative electrode can be 4 N / mm or more. As for the tensile strength of the said negative electrode, 7 N / mm or more is more preferable. On the other hand, if the tensile strength of the negative electrode is too large, the thickness of the Al layer becomes too large, and the volume of the core material part that does not contribute to charging / discharging increases and the volume energy density of the battery decreases, so The upper limit of strength is preferably about 11 N / mm.

  Examples of the Al base material include a foil made of Al (and inevitable impurities) and Cu, Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, Mo, and the like as alloy components, with the balance being the remainder. Examples include foils made of Al and Al alloys that are inevitable impurities (the content of the alloy components is, for example, 50% by mass or less in total). For example, when the alloy component of the Al base is Cu, the Cu content is preferably 7% by mass or less, more preferably 2% by mass or less, and more preferably 0.4% by mass or less. If it is this range, the elution of Cu at the time of overdischarge can be suppressed more reliably.

The thickness of the Al base material as the negative electrode precursor is preferably 30 μm or more, more preferably 40 μm or more, preferably 150 μm or less, and more preferably 100 μm or less. If the thickness of the Al base is within the above range, the capacity of the negative electrode can be made constant or higher while the tensile strength of the negative electrode after charging is 4 N / mm or more. However, since the nonaqueous electrolyte battery of the present embodiment is configured with positive electrode capacity regulation, when the thickness of the Al base material as the negative electrode precursor is 30 μm or more and 150 μm or less, the tensile strength of the negative electrode after charging is set. In order to set it to 4 N / mm or more, the capacity of the positive electrode is preferably 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less, and more preferably 3.65 mAh / cm ² or less.

  The Al base material used as the negative electrode precursor can be provided with a negative electrode lead body according to a conventional method.

  In FIG. 1, sectional drawing which represents typically an example of the Al base material used for the negative electrode precursor of the nonaqueous electrolyte battery of this embodiment is shown. In FIG. 1, the thickness a of the Al base material (negative electrode precursor) 100 is set to 30 μm or more and 150 μm or less.

  FIG. 2 is a cross-sectional view schematically showing an example of a state in which the negative electrode is formed by first charging (forming) the Al base material 100 of FIG. In FIG. 2, the negative electrode 200 includes an Al layer 201 and a Li—Al alloy layer 202 formed on the surface of the Al layer 201. The thickness b of the Al layer 201 is smaller than the thickness a of the Al base material in FIG. 1 due to the formation of the Li—Al alloy layer 202. On the other hand, since the thickness c of the Li—Al alloy layer 202 expands in the direction of the arrow in FIG. 2 due to the reaction between Al and Li ions, the thickness (c + b + c) of the negative electrode 200 is the thickness of the original Al base layer. Greater than a. However, in reality, the reaction between the Al base layer and Li ions does not necessarily occur uniformly, and undulations occur at the interface between the Al layer 201 and the Li—Al alloy layer 202, so the thickness b of the Al layer 201 Although the thickness c of the Li—Al alloy layer 202 varies depending on the location, the thickness a of the Al base material before the formation is usually uniform.

  Further, in the non-aqueous electrolyte battery of this embodiment, the area of the negative electrode is set larger than the area of the positive electrode mixture layer capable of occluding and releasing positive electrode Li ions described later, and the negative electrode has a separator. Is disposed so as to cover the entire surface of the positive electrode mixture layer, the end of the negative electrode is a portion that does not face the positive electrode mixture layer, and in that portion, the Li-Al alloy layer is substantially It is thought that it is not formed. Therefore, when the total thickness of the Al layer of the negative electrode is observed, the thickness b of the Al layer where the Li-Al alloy layer is formed is greater than the thickness a of the Al base material before the initial charge. Although the thickness of the Al layer in the portion where the Li—Al alloy layer is not formed is maintained as it is, the thickness “a” of the Al base material before the initial charge is maintained as it is. Is equal to the thickness a of the Al base material (negative electrode precursor) before the initial charge.

  The positive electrode mixture layer as used herein refers to a portion of the positive electrode that can occlude / release Li ions. For example, after a layer containing a positive electrode active material is formed on a positive electrode current collector, when a layer (such as a tape) that inhibits the transmission of Li ions is pasted on the layer, the layer of the pasted portion is This does not correspond to the positive electrode mixture layer in the present embodiment.

  The Al layer 201 and the Li—Al alloy layer 202 in FIG. 2 can be identified by observing the cross section of the negative electrode with a scanning electron microscope (SEM). Further, whether or not the negative electrode is broken can be confirmed by observing the cross section of the negative electrode with an SEM.

<Positive electrode>
The positive electrode according to the non-aqueous electrolyte battery of the present embodiment has, for example, a structure having a positive electrode mixture layer containing a positive electrode active material, a conductive additive, a binder and the like on one side or both sides of the positive electrode current collector. Can be used. As described above, when the maximum thickness of the negative electrode Al layer is 30 μm or more and 150 μm or less, that is, when the thickness of the Al base material that is the negative electrode precursor before initial charging (chemical conversion) is 30 μm or more and 150 μm or less. The capacity of the positive electrode is preferably set to 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less. Thereby, the Al base material of the negative electrode precursor does not react too much with Li ions, the thickness of the Al layer of the negative electrode becomes too thin, and the tensile strength of the negative electrode does not fall below 4 N / mm.

The capacity of the positive electrode is measured as follows. That is, the non-aqueous electrolyte battery of this embodiment is disassembled after initial charging (chemical conversion), and the positive electrode is taken out. Then, when the taken-out positive electrode has a positive electrode mixture layer only on one side of the positive electrode current collector, the positive electrode mixture layer portion of the positive electrode is cut out to a size of 1 cm ² to obtain a positive electrode capacity measurement sample. . Moreover, when the taken-out positive electrode has a positive electrode mixture layer on both surfaces of the positive electrode current collector, the positive electrode of the positive electrode in which the positive electrode mixture layer on one side is removed from the taken-out positive electrode and the positive electrode mixture layer is removed from the one side A portion of the mixture layer is cut out to a size of 1 cm ² to obtain a positive electrode capacity measurement sample. Next, a model cell is produced by combining the positive electrode capacity measurement sample and the Li foil. As the non-aqueous electrolyte of this model cell, the same non-aqueous electrolyte as that used in the non-aqueous electrolyte battery of this embodiment is used. Subsequently, this model cell was charged at a constant current of 0.25 mA to a predetermined voltage obtained by adding 0.35 V to the initial charging voltage of the nonaqueous electrolyte battery, and then the charging current was 0 at the predetermined voltage. Charge at a constant voltage until it drops to 0.025 mA. Thereafter, discharging is performed at a constant current of 0.25 mA until 3 V is reached, and the capacity at that time is taken as the capacity of the positive electrode.

Further, the mass of the positive electrode mixture layer formed on each surface of the positive electrode current collector, is preferably, 8.5 mg / cm ² or more 25 mg / cm ² or less is at 7 mg / cm ² or more 30 mg / cm ² or less It is more preferable. When the mass of the positive electrode mixture layer is less than 7 mg / cm ² , the discharge load per unit mass of the positive electrode active material at the time of high rate discharge increases and the output characteristics deteriorate, and the mass of the positive electrode mixture layer is 30 mg. it exceeds / cm ^2, because it may be difficult to set the upper limit of the capacity of the positive electrode to 4.87mAh / cm ^2.

  The mass of the positive electrode mixture layer can be controlled by adjusting the coating amount of the positive electrode mixture per unit area on the positive electrode current collector.

  Although it does not specifically limit as said positive electrode active material, It is preferable to use a lithium containing nickel layered oxide.

  In general, the positive electrode active material reacts with a non-aqueous electrolyte in a high temperature environment, a reaction product is deposited on the positive electrode, and gas is simultaneously generated. When lithium cobaltate, which is commonly used in nonaqueous electrolyte batteries such as lithium ion secondary batteries, is used as the positive electrode active material, the surface of lithium cobaltate reacts with the nonaqueous electrolyte at high temperatures to produce Co. The reaction product containing is deposited on the surface of the positive electrode and gas is generated at the same time, but the reaction product containing Co is further decomposed and Co is eluted into the non-aqueous electrolyte. Then, the surface of the lithium cobalt oxide again reacts with the nonaqueous electrolytic solution to produce a reaction product containing Co and gas. That is, if the positive electrode active material contains a large amount of lithium cobalt oxide, Co will continue to elute each time the battery is exposed to high temperatures, and gas will continue to be generated.

  However, the lithium-containing nickel layered oxide once reacts with the non-aqueous electrolyte at a high temperature to generate a reaction product containing Ni and generate gas, but the reaction product containing Ni is not decomposed. It stays on the positive electrode and becomes a film. Further, even if the battery is exposed to a high temperature after that, Ni elution and gas generation are suppressed. Therefore, metal elution is unlikely to occur even at high temperatures with the battery charged. Therefore, gas generation can be suppressed even when the battery is stored at a high temperature for a long period of time, and a decrease in discharge capacity can be suppressed.

  As the lithium-containing nickel layered oxide, a composite oxide represented by the following general formula (1) is preferably used. When the composite oxide represented by the following general formula (1) is used, not only gas generation during long-term storage but also increase in resistance can be suppressed.

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 an element other than Ni and M ¹ , and −0.1 ≦ x ≦ 0.1, 0 ≦ y <0.85, and 0 ≦ z ≦ 0.05.

  When Co is present in the crystal lattice in the composite oxide represented by the general formula (1), from the phase transition of the lithium-containing composite oxide due to the insertion and desorption of Li during charge / discharge of the nonaqueous electrolyte battery. Since the irreversible reaction that occurs can be relaxed and the reversibility of the crystal structure of the composite oxide can be increased, a non-aqueous electrolyte battery having a longer charge / discharge cycle life can be formed.

When the complex oxide represented by the general formula (1) contains Mg, Mg ²⁺ is rearranged to the Li site when phase transition of the complex oxide occurs due to Li desorption and insertion. This alleviates the irreversible reaction and improves the reversibility of the layered crystal structure of the composite oxide represented as space group R3-m.

  When the composite oxide represented by the general formula (1) contains Mn, the tetravalent Mn stabilizes the unstable tetravalent Ni. An electrolyte battery can be configured.

  When the composite oxide represented by the general formula (1) contains W or Mo, the rate of expansion / contraction of the crystals during charge / discharge can be reduced, and the charge / discharge cycle characteristics of the battery. It leads to improvement.

  In the composite oxide represented by the general formula (1), when Al is present in the crystal lattice, the crystal structure can be stabilized and the thermal stability thereof can be improved. A high nonaqueous electrolyte battery can be configured. In addition, since Al is present at the grain boundaries and surfaces of the composite oxide particles, the stability with time and side reactions with the non-aqueous electrolyte can be suppressed, and a longer-life non-aqueous electrolyte battery can be obtained. Can be configured.

  When Er is present at the grain boundaries and surfaces of the composite oxide particles represented by the general formula (1), the catalytic properties 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 composite 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 composite oxide is improved. Side reactions with the non-aqueous electrolyte are suppressed, and a battery that is less likely to swell during high temperature storage can be configured.

In the composite oxide represented by the general formula (1), when Ti is contained in the particles, the LiNiO ₂ type crystal structure is arranged in a crystal defect portion such as an oxygen vacancy to stabilize the crystal structure. Therefore, the reversibility of the reaction of the composite oxide is increased, and a non-aqueous electrolyte battery having better charge / discharge cycle characteristics can be configured.

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

In the composite oxide represented by the general formula (1), the element of M ¹ may or may not contain each of the above elements depending on the required characteristics.

The complex 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 . If z representing the content of the element of M ² is 0.05 or less, the effect in the present embodiment is not inhibited, but is more preferably 0.01 or less.

  The composition 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 added in order and dissolved by heating. After cooling, the solution is further diluted 25 times with pure water, and the ICP analyzer “ICP-757” (product name) manufactured by JARRELASH Is used to analyze the composition by the calibration curve method. The composition amount can be derived from the obtained results.

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

  Further, the positive electrode active material can contain another lithium-containing composite oxide different from the lithium-containing nickel layered oxide, depending on required battery characteristics.

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 , Spinel-structured lithium-containing composite oxides such as Li _4/3 Ti _5/3 O ₄ ; Olivine-structured lithium-containing composite oxides such as LiFePO ₄ ; And oxides substituted with other elements. One of these lithium-containing composite oxides may be used, or two or more thereof may be used.

  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 preferable, and it is further more preferable to contain 80 mass% or more. This is because the effect of the lithium-containing nickel layered oxide can be obtained satisfactorily.

  Examples of the conductive auxiliary agent related to the positive electrode mixture layer include carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; carbon 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), carboxymethyl cellulose (CMC), and polyvinylpyrrolidone (PVP).

  For the positive electrode, for example, a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder is dispersed in an organic solvent such as N-methyl-2-pyrrolidone (NMP) or water, and a positive electrode mixture-containing paint (paste) , Slurry, etc.) is prepared, and this positive electrode mixture-containing coating is applied to one or both sides of the current collector and dried, and then subjected to a press treatment as necessary.

  Alternatively, a molded body may be formed using the positive electrode mixture, and a part or all of one side of the molded body may be bonded to the 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 metal foil such as Al or Al alloy, a punching metal, a net, an expanded metal, or the like can be used, but usually an Al foil is preferably 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. It is preferable. Moreover, it is preferable that the thickness of a positive mix layer is 15-100 micrometers per single side | surface of a collector.

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

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

<Electrode body>
In the nonaqueous electrolyte battery of the present embodiment, the positive electrode and the negative electrode are, for example, an electrode body formed by stacking via 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 laminated, but in the case of a rectangular battery in which a wound electrode body is enclosed in a rectangular outer casing as compared with a cylindrical battery, Since a large stress is applied to the R portion of the negative electrode, the strength of the negative electrode can be maintained even when aluminum is used alone as a negative electrode material, and long-term reliability in a high temperature environment can be secured. The configuration is preferably used.

<Non-aqueous electrolyte>
As 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 electrolyte include cyclic carbonates such as ethylene carbonate, propylene carbonate (PC), butylene carbonate, and vinylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; methyl propionate Chain esters such as compounds having a lactone ring; chain ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme, tetraglyme; dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, etc. Cyclic ethers; nitriles such as acetonitrile, propionitrile, methoxypropionitrile; sulfites such as ethylene glycol sulfite; Gerare, it can also be used as a mixture of two or more. In order to obtain a battery having 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-described chain carbonate.

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

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

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

  The lactone having a substituent at the α-position is preferably, for example, a 5-membered ring (having 4 carbon atoms constituting the ring). The α-position substituent of the lactone may be one or two.

  Examples of the substituent include a hydrocarbon group and a halogen group (fluoro group, chloro group, bromo group, 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, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, and the like are more preferable.

  Specific examples of lactones having a substituent at the α-position include 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-butyrolac Emissions, and the like, 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 electrolyte is preferably 10% by volume or more, and preferably 30% by volume or more, from the viewpoint of ensuring the above-described effects due to its use. More preferred. As described above, since the organic solvent of the nonaqueous electrolytic solution may be only PC, the upper limit value of the preferred content of PC in the total organic solvent used in the nonaqueous 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 in the non-aqueous electrolyte is 0.1% by mass from the viewpoint of ensuring a good effect due to the use. It is preferable to use it within the range where the preferable value is satisfied and the PC content in the total organic solvent satisfies the preferable value.

Lithium salts related to non-aqueous electrolytes have high heat resistance and can improve the storage characteristics of non-aqueous electrolyte batteries in high-temperature environments, and also have a function to suppress corrosion of aluminum used in the batteries. Therefore, it is preferable to use LiBF ₄ .

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 Rf is a fluoroalkyl group], etc. Is mentioned.

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

The concentration of the total lithium salt in the non-aqueous electrolyte is preferably 1.8 mol / L or less, and more preferably 1.6 mol / L or less. Therefore, when only LiBF ₄ is used for the lithium salt, it is preferable to use it in a range where the concentration satisfies the above-described preferred upper limit value. 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 electrolyte 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, which suppresses gas generation due to oxidative decomposition of the non-aqueous electrolyte. In particular, the battery can be prevented from swelling when stored in a high temperature environment.

  Nitrile compounds added to the non-aqueous electrolyte include mononitriles such as acetonitrile, propionitrile, butyronitrile, valeronitrile, benzonitrile, acrylonitrile; malononitrile, succinonitrile, glutaronitrile, adiponitrile, 1,4-dicyanoheptane 1,5-dicyanopentane (pimelonitrile), 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 and 2,4-dimethylglutaronitrile; cyclic nitriles such as benzonitrile; methoxyacetoni Lil alkoxy-substituted nitriles such as; include such is, it may be used only one of these, or two or more may be used. Among these nitrile compounds, dinitrile is more preferable, and adiponitrile, pimelonitrile, and suberonitrile are still more 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 ensuring the above-described effects due to their use. Is more preferable. However, if the amount of the nitrile compound in the non-aqueous electrolyte is too large, the discharge characteristics at low temperatures of the battery tend to deteriorate. Therefore, the content of the nitrile compound in the non-aqueous electrolyte used in the battery is limited from the viewpoint of limiting the amount of the nitrile compound in the non-aqueous electrolyte to a certain extent and improving the discharge characteristics at a low temperature of the battery. The content is preferably 10% by mass or less, and more preferably 5% by mass or less.

  Moreover, it is preferable that the non-aqueous electrolyte contains the phosphoric acid compound or boric acid compound which has group represented by following General formula (2) in a molecule | numerator.

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 Represents an aryl group having 6 to 10 carbon atoms, and part or all of the hydrogen atoms may be substituted with fluorine.

  For example, batteries used for in-vehicle devices and outdoor equipment are not limited to high-temperature environments and can be used in cold regions. Under a low temperature environment, the operability of the battery is lower than that at normal temperature, and in particular, a battery that has deteriorated over time tends to have lower discharge characteristics. Therefore, it is preferable that high-rate discharge can be performed even in a low temperature environment after being placed in a high temperature environment for a certain period of time (substantially the same state as aging) assuming use at any temperature.

  In the non-aqueous electrolyte battery of the present embodiment, when a non-aqueous electrolyte containing a phosphoric acid compound or boric acid compound having a group represented by the general formula (2) in the molecule is used, a long period of time at a high temperature is used. It is possible to enhance the high rate discharge characteristics in a low temperature environment after storage. The reason for this is not clear, but the present inventors presume as follows.

  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 its molecule is used, the phosphoric acid compound or boric acid compound is a surface of the positive electrode active material described above. Therefore, even if the battery is stored at a high temperature for a long period of time, the film is not destroyed, so that elution of metal from the positive electrode active material can be suppressed. Further, since this coating hardly inhibits the insertion of Li ions even at a low temperature, the high rate discharge characteristics at a low temperature of the battery after long-term storage at a high temperature can be improved.

  Furthermore, also in the negative electrode of a nonaqueous electrolyte battery, the phosphoric acid compound or boric acid compound acts 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 to form a thin and good-quality film on the negative electrode surface. Thereby, since the coating on the surface of the negative electrode is not broken even during long-term storage at a high temperature, deterioration of the negative electrode can be suppressed. In addition, this coating hardly inhibits Li ion desorption even at low temperatures. For these reasons as well, the high rate discharge characteristics at low temperature of the battery after long-term storage at high temperature can be improved.

  As described above, by combining the specific positive electrode and the specific negative electrode according to the present embodiment and the nonaqueous electrolytic solution containing the phosphoric acid compound or the boric acid compound, each of the above functions functions synergistically. Thus, a battery having better storage characteristics in a high temperature environment and capable of responding to temperature changes can be obtained.

In the general formula (2), X is Si, Ge or Sn, but Si is more preferable. 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 are each independently 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, a methyl group or an ethyl group is more preferable. The group represented by the general formula (2) is particularly preferably a trimethylsilyl group.

  In the phosphoric acid compound, only one of the hydrogen atoms possessed by phosphoric acid may be substituted with the group represented by the general formula (2). Two of them may be substituted with a group represented by the general formula (2), and all three hydrogen atoms of phosphoric acid may be substituted with a group represented by the general formula (2). However, it is more preferable that all three 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 particularly preferable.

  Further, in the boric acid compound, only one of the hydrogen atoms possessed by boric acid may be substituted with the group represented by the general formula (2). Two of them may be substituted with a group represented by the general formula (2), and all three hydrogen atoms of boric acid may be substituted with a group represented by the general formula (2). However, it is more preferable that all three hydrogen atoms of boric acid are substituted with the group represented by the general formula (2).

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

  The content of the phosphoric acid compound or boric acid compound having in the molecule thereof the group represented by the general formula (2) in the non-aqueous electrolyte used in the battery ensures the above-mentioned effect due to its use better. In view of the above, it is preferably 0.2% by mass or more, and more preferably 0.5% by mass or more. In addition, if the content is too large, the amount of gas generated at the time of film formation increases, so phosphoric acid having a group represented by the general formula (2) in the molecule 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 phosphoric acid compound or boric acid compound, LiBF ₄ is contained as a lithium salt, PC is contained as an organic solvent, and a nitrile compound is further added. It is particularly preferred to use When such a non-aqueous electrolyte is used, the action of each component functions synergistically to suppress the swelling of the battery during high temperature storage to a higher level, and in a low temperature environment after high temperature storage (for example, The discharge characteristics at −20 ° C. or lower can be further improved.

  In addition, for the purpose of further improving various characteristics of the battery in these non-aqueous electrolytes, vinylene carbonates, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl, fluorobenzene, t-butylbenzene, etc. Additives can also be added as appropriate. Furthermore, the nonaqueous electrolytic solution may be made into a gel (gel electrolyte) using a known gelling agent such as a polymer.

<Nonaqueous electrolyte battery>
The non-aqueous electrolyte battery according to the present embodiment includes, for example, an electrode body that is loaded in the exterior body, a non-aqueous electrolyte solution is injected into the exterior body, and the electrode body is immersed in the non-aqueous electrolyte solution. It is manufactured by sealing the opening. As the exterior body, an exterior body made of steel, aluminum, aluminum alloy, an exterior body composed of a laminated film on which a metal is deposited, or the like can be used.

  Since the non-aqueous electrolyte battery of the present embodiment is configured with positive electrode capacity regulation, the charging end time can be detected by controlling the amount of charged electricity or controlling the charging voltage. 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 proceeds in the negative electrode by the aging treatment, the discharge capacity and output characteristics of the battery are further improved.

Next, an embodiment of a method for manufacturing a nonaqueous electrolyte battery disclosed in the present application will be described. The method for producing a non-aqueous electrolyte battery according to this embodiment is a method for producing the non-aqueous electrolyte battery according to the above-described embodiment, wherein a positive electrode mixture layer is formed on at least one surface of the positive electrode current collector, and the capacity A positive electrode having a thickness of 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less, an area larger than the area of the positive electrode mixture layer of the positive electrode, and a thickness of 30 μm or more and 150 μm A step of preparing a negative electrode precursor comprising the following aluminum base, and a step of producing an electrode body by disposing the negative electrode precursor so as to cover the entire surface of the positive electrode mixture layer of the positive electrode via a separator And a step of charging the electrode body and the non-aqueous electrolyte solution after enclosing them in an exterior body.

  In the step of preparing the positive electrode, the positive electrode described in the nonaqueous electrolyte battery of the embodiment is prepared. In the step of preparing the negative electrode precursor, the negative electrode precursor described in the non-aqueous electrolyte battery of the embodiment is prepared. The separator and the non-aqueous electrolyte described in the non-aqueous electrolyte battery of the embodiment are also used for the separator and the non-aqueous electrolyte.

By using an Al base material having a thickness of 30 μm or more and 150 μm or less as a negative electrode precursor and using a positive electrode having a capacity of 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less, after the initial charge (formation) step, A negative electrode including an Al layer and a Li—Al alloy layer formed on the surface of the Al layer is formed, and the tensile strength of the negative electrode can be 4 N / mm or more. Once the negative electrode is formed, even if charging and discharging are performed again, the thickness of the Al layer constituting the negative electrode is not significantly changed, and the negative electrode can maintain a certain tensile strength.

  Thus, according to the manufacturing method of the present embodiment, the strength of the negative electrode can be maintained even when aluminum is used alone as the negative electrode material, and a non-aqueous electrolyte battery with high long-term reliability in a high temperature environment can be provided.

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

Example 1
<Preparation of positive electrode>
First, lithium-containing nickel layered oxide represented by LiNi _0.33 Co _0.33 Mn _0.33 O _{2 as} a positive electrode active material: 97 parts by mass, acetylene black as a conductive additive: 1.5 parts by mass, and PVDF as a binder : A positive electrode mixture-containing slurry in which 1.5 parts by mass was dispersed in NMP was prepared. Next, this positive electrode mixture-containing slurry was applied to both sides of an Al foil having a thickness of 12 μm, dried, and subjected to a press treatment, whereby a mass of 10 mg / cm ² per side was obtained on each side of the Al foil current collector. The positive electrode mixture layer was formed. Furthermore, a strip-shaped positive electrode having a length of 974 mm and a width of 40 mm was produced by pressing the positive electrode mixture layer. However, the positive electrode mixture layer is not formed on a part of the application surface of the slurry, and a portion where the Al foil is exposed is provided, and the portion where the Al foil is exposed is made of Al for conductive connection with the outside of the battery. The lead body was ultrasonically welded.

<Preparation of negative electrode precursor>
A strip-shaped Al foil having a thickness of 70 μm, a length of 988 mm, and a width of 44 mm was used as the negative electrode precursor. However, a Ni lead body for conductive connection with the outside of the battery was ultrasonically welded to the end of the Al foil.

<Production of electrode body>
The positive electrode and the negative electrode precursor were laminated via a separator made of PE microporous film having a thickness of 16 μm, wound in a spiral shape, and then crushed to produce a flat wound electrode body.

<Preparation of non-aqueous electrolyte>
LiBF ₄ is dissolved at a concentration of 1.2 mol / L in a mixed solvent of propylene carbonate (PC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 17:63:20, and adiponitrile is further added in 5%. A nonaqueous electrolytic solution was prepared by adding 2% by mass of mass% and tris (phosphate trimethylsilyl: TMSP).

<Battery assembly>
By encapsulating the wound electrode body and the non-aqueous electrolyte in an outer can made of Al alloy having a size of 103450 and a thickness of 0.8 mm, the rated capacity is 800 mAh, and the rectangular shape shown in FIGS. A non-aqueous electrolyte battery was produced.

  Here, FIG. 3 and FIG. 4 will be described. FIG. 3 is a perspective view schematically showing the nonaqueous electrolyte battery of this example, and FIG. 4 is a cross-sectional view taken along the line II of FIG. is there. In FIG. 4, the inner peripheral portion of the electrode body and the separator are not cross-sectioned. 3 and 4, the positive electrode 1 and the negative electrode 2 are wound in a spiral shape via a separator 3, and then pressed so as to be flattened to form a flat wound electrode body 6 having a rectangular shape (a rectangular tube). Is housed together with a non-aqueous electrolyte. However, in FIG. 4, in order to avoid complication, the Al foil as the current collector used in the production of the positive electrode 1, the non-aqueous electrolyte, and the like are not illustrated.

  The outer can 4 is made of an aluminum alloy and constitutes an outer casing of the battery. The outer can 4 also serves as a positive electrode terminal. And the insulator 5 which consists of a polyethylene sheet is arrange | positioned at the bottom part of the armored can 4, From the flat wound electrode body 6 which consists of the positive electrode 1, the negative electrode 2, and the separator 3, it is in each one end of the positive electrode 1 and the negative electrode 2 The connected positive electrode lead body 7 and negative electrode lead body 8 are drawn out. A stainless steel terminal 11 is attached to a sealing lid plate 9 made of aluminum alloy for sealing the opening of the outer can 4 via a polypropylene insulating packing 10, and an insulator 12 is attached to the terminal 11. A stainless steel lead plate 13 is attached via

  And this cover plate 9 is inserted in the opening part of the armored can 4, and the opening part of the armored can 4 is sealed by welding the junction part of both, and the inside of a battery is sealed. The lid plate 9 is provided with a non-aqueous electrolyte inlet 14, and the non-aqueous electrolyte inlet 14 is welded and sealed with a sealing member inserted therein, thereby sealing the battery. Is secured. Further, the lid plate 9 is provided with a cleavage vent 15 as a mechanism for discharging the internal gas to the outside when the temperature of the battery rises.

(Example 2)
A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that an Al foil having a thickness of 38 μm, a length of 988 mm, and a width of 44 mm was used as the negative electrode precursor.

(Example 3)
As the negative electrode precursor, an Al foil having a thickness of 56 μm, a length of 988 mm, and a width of 44 mm was used. A positive electrode was produced in the same manner as in Example 1, except that a positive electrode mixture layer having a mass of 25 mg / cm ² per side was formed on both sides of the Al foil current collector. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that the negative electrode precursor and the positive electrode were used.

Example 4
The lithium-containing nickel layered oxide represented by LiNi _0.80 Co _0.15 Al _0.05 O ₂ : 97 parts by mass was used as the positive electrode active material instead of the positive electrode active material of Example 1, and was the same as in Example 1. A positive electrode was produced. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 5)
Instead of the positive electrode active material of Example 1, lithium-containing nickel layered oxide represented by LiNi _0.5 Co _0.2 Mn _0.3 O ₂ : The same as in Example 1 except that 97 parts by mass was used as the positive electrode active material. A positive electrode was produced. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 6)
A positive electrode was produced in the same manner as in Example 1, except that 97 parts by mass of lithium-containing composite oxide represented by LiCoO ₂ was used as the positive electrode active material instead of the positive electrode active material of Example 1. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 7)
A positive electrode was produced in the same manner as in Example 1, except that 97 parts by mass of lithium-containing composite oxide represented by LiMn ₂ O ₄ was used as the positive electrode active material instead of the positive electrode active material of Example 1. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Example 8)
As the negative electrode precursor, an Al foil having a thickness of 31 μm, a length of 988 mm, and a width of 44 mm was used. Further, instead of the positive electrode active material of Example 1, a lithium-containing composite oxide represented by LiMn ₂ O _4: with 97 parts by mass as a positive electrode active material, on both sides of the Al foil current collector, 7 mg per one side respectively A positive electrode was produced in the same manner as in Example 1 except that a positive electrode mixture layer having a mass of / cm ² was formed. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that the negative electrode precursor and the positive electrode were used.

Example 9
Instead of the positive electrode active material of Example 1, lithium-containing composite oxide represented by LiNi _0.80 Co _0.15 Al _0.05 O ₂ : 97 parts by mass was used as the positive electrode active material, A positive electrode was produced in the same manner as in Example 1 except that a positive electrode mixture layer having a mass of 30 mg / cm ² was formed. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that this positive electrode was used.

(Comparative Example 1)
A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that an Al foil having a thickness of 25 μm, a length of 988 mm, and a width of 44 mm was used as the negative electrode precursor.

(Comparative Example 2)
As the negative electrode precursor, an Al foil having a thickness of 60 μm, a length of 988 mm, and a width of 44 mm was used. A positive electrode was produced in the same manner as in Example 1 except that a positive electrode mixture layer having a mass of 40 mg / cm ² per side was formed on both surfaces of the Al foil current collector. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that the negative electrode precursor and the positive electrode were used.

(Comparative Example 3)
As the negative electrode precursor, an Al foil having a thickness of 40 μm, a length of 988 mm, and a width of 44 mm was used. A positive electrode was produced in the same manner as in Example 1 except that a positive electrode mixture layer having a mass of 20 mg / cm ² per side was formed on both sides of the Al foil current collector. A nonaqueous electrolyte battery was produced in the same manner as in Example 1 except that the negative electrode precursor and the positive electrode were used.

  Table 1 shows the configurations of the positive electrodes of the nonaqueous electrolyte batteries of Examples 1 to 9 and Comparative Examples 1 to 3.

  About the nonaqueous electrolyte battery of Examples 1-9 and Comparative Examples 1-3, the capacity | capacitance of a positive electrode, the tensile strength of a negative electrode, and the high temperature storage characteristic were evaluated.

<Capacitance of positive electrode>
About each battery of an Example and a comparative example, the constant charge (100 mA) / constant voltage (3.8V) initial charge (formation) is performed, and when the charge current decreases to 10 mA, the charge is stopped and the fully charged state is obtained. did. Next, each battery is disassembled, the positive electrode is taken out, the positive electrode mixture layer on one side of the taken-out positive electrode is removed, and the positive electrode mixture layer portion from which the positive electrode mixture layer is removed from one side is 1 cm ^2. A positive electrode capacity measurement sample was cut out to a size of. Subsequently, a model cell was produced by combining the positive electrode capacity measurement sample and Li foil. As the non-aqueous electrolyte of this model cell, the same non-aqueous electrolyte as that used in each battery was used. Next, this model cell was charged at a constant current of 0.25 mA to a constant current of 4.15 V obtained by adding 0.35 V to the initial charge voltage 3.8 V of each battery, and then charged at a voltage of 4.15 V. Was charged at a constant voltage until the current decreased to 0.025 mA. Thereafter, discharging was performed at a constant current of 0.25 mA until 3 V was reached, and the capacity at that time was defined as the capacity of the positive electrode.

<Tensile strength of negative electrode>
About each battery of an Example and a comparative example, the constant charge (100 mA) / constant voltage (3.8V) initial charge (formation) is performed, and when the charge current decreases to 10 mA, the charge is stopped and the fully charged state is obtained. did. Each battery in a fully charged state was disassembled, the negative electrode was taken out, and the negative electrode was cut into a 10 mm × 50 mm rectangular shape to obtain a test piece. The test piece was attached to a tensile tester “SDT-52 type” (product name) manufactured by Imada Seisakusho with a distance between chucks of 30 mm, a tensile test was performed at a crosshead speed of 10 mm / min, and a tensile strength was measured. .

<High temperature storage characteristics>
About each battery of an Example and a comparative example, the constant charge (100 mA) / constant voltage (3.8V) initial charge (formation) is performed, and when the charge current decreases to 10 mA, the charge is stopped and the fully charged state is obtained. did. Each battery in the fully charged state was discharged at a constant current of 2000 mA until it reached 2.0 V, and the initial discharge capacity was determined.

  Next, each battery that was fully charged under the same conditions as the first charge was stored at 100 ° C. for 150 days. Thereafter, the battery was fully charged under the same conditions as described above, and was discharged in a 20 ° C. environment at a constant current of 2000 mA until it reached 2.0 V, and the discharge capacity after storage was determined.

Subsequently, the capacity retention rate after storage was calculated according to the following formula, and the high temperature storage characteristics were evaluated according to the following evaluation criteria.
Capacity retention rate (%) = (discharge capacity after storage / initial discharge capacity) × 100
When the capacity retention rate is 70% or more: Excellent high-temperature storage characteristics (○)
When the capacity retention rate is 50 to 69%: Good high-temperature storage characteristics (△)
When capacity retention is 49% or less: High temperature storage characteristics are poor (×)

  The evaluation results are shown in Table 2.

  From Table 2, in the batteries of Examples 1 to 9 in which the negative electrode had a tensile strength of 4 N / mm or more, the evaluation of the high-temperature storage characteristics could be excellent or good, and the long-term reliability in a high-temperature environment was high. It can be seen that the battery was realized. On the other hand, in the batteries of Comparative Examples 1 to 3 in which the tensile strength of the negative electrode was less than 4 N / mm, it was found that the evaluation of the high temperature storage characteristics was poor and the high temperature storage characteristics were inferior.

  The non-aqueous electrolyte battery disclosed in this application has high long-term reliability in a high-temperature environment. Therefore, taking advantage of these characteristics, the non-aqueous electrolyte battery can be used for power supplies for in-vehicle equipment and power supplies for equipment for outdoor facilities. It can be preferably applied to applications that require good capacity maintenance over a long period of time in an environment.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Exterior can 5 Insulator 6 Winding electrode body 7 Positive electrode lead body 8 Negative electrode lead body 9 Cover plate 10 Insulation packing 11 Terminal 12 Insulator 13 Lead plate 14 Nonaqueous electrolyte inlet 15 Cleavage vent 100 Al substrate (negative electrode precursor)
200 Negative electrode 201 Al layer 202 Li-Al alloy layer

Claims (14)

A non-aqueous electrolyte battery including a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator,
The positive electrode includes a positive electrode current collector and a positive electrode mixture layer formed on the positive electrode current collector,
The positive electrode mixture layer can occlude and release Li ions,
The area of the negative electrode is larger than the area of the positive electrode mixture layer of the positive electrode, and the negative electrode is disposed so as to cover the entire surface of the positive electrode mixture layer via the separator,
The negative electrode includes an Al layer and a Li-Al alloy layer formed on the surface of the Al layer,
A non-aqueous electrolyte battery characterized in that the negative electrode has a tensile strength of 4 N / mm or more. The maximum thickness of the Al layer is 30 μm or more and 150 μm or less,
The nonaqueous electrolyte battery according to claim 1, wherein the capacity of the positive electrode is 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less. The positive electrode mixture layer is formed on at least one surface of the positive electrode current collector,
The nonaqueous electrolyte battery according to claim 1, wherein a mass of the positive electrode mixture layer per one side of the positive electrode current collector is 7 mg / cm ² or more and 30 mg / cm ² or less. The positive electrode, the negative electrode and the separator form a wound electrode body,
The non-aqueous electrolyte battery according to any one of claims 1 to 3, wherein the wound electrode body is enclosed in a rectangular exterior body.   The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode mixture layer includes a lithium-containing nickel layered oxide as a positive electrode active material. The non-aqueous electrolyte battery according to any one of claims 1 to 5, 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 an element other than Ni and M ¹ , and −0.1 ≦ x ≦ 0.1, 0 ≦ y <0.85, and 0 ≦ z ≦ 0.05.   The non-aqueous electrolyte battery according to claim 5, wherein the positive electrode active material further includes a lithium-containing composite oxide different from the lithium-containing nickel layered oxide. The nonaqueous electrolytic solution according to any one of claims 1 to 7, wherein the nonaqueous electrolytic solution further includes 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 Represents an aryl group having 6 to 10 carbon atoms, and part or all of the hydrogen atoms may be substituted with fluorine.   The non-aqueous electrolyte battery according to claim 8, wherein the non-aqueous electrolyte includes 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 includes tris (trimethylsilyl) borate as a boric acid compound having a group represented by the general formula (2) in the molecule. The non-aqueous electrolyte battery according to any one of claims 1 to 10, wherein the non-aqueous electrolyte includes LiBF ₄ as a lithium salt, propylene carbonate as an organic solvent, and further includes a nitrile compound.   The non-aqueous electrolyte battery according to claim 11, wherein the non-aqueous electrolyte includes at least one selected from the group consisting of suberonitrile, pimelonitrile, and adiponitrile as the nitrile compound.   The non-aqueous electrolyte battery according to claim 11 or 12, wherein the content of the nitrile compound in the non-aqueous electrolyte is 0.1 mass% or more and 10 mass% or less. A method for producing the nonaqueous electrolyte battery according to any one of claims 1 to 13,
Preparing a positive electrode in which a positive electrode mixture layer is formed on at least one surface of the positive electrode current collector and having a capacity of 0.68 mAh / cm ² or more and 4.87 mAh / cm ² or less;
A step of preparing a negative electrode precursor having an area larger than the area of the positive electrode mixture layer of the positive electrode and having a thickness of 30 μm or more and 150 μm or less;
Arranging the negative electrode precursor so as to cover the entire surface of the positive electrode mixture layer of the positive electrode through a separator, and producing an electrode body;
A method for producing a water electrolyte battery, comprising: charging the electrode body and the nonaqueous electrolyte solution after enclosing them in an exterior body.

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