Method for manufacturing a non-aqueous electrolyte battery

Abstract

To provide a production method for a non-aqueous electrolyte battery excellent in high-temperature storage characteristics and load characteristics at low temperature.SOLUTION: A production method for a non-aqueous electrolyte battery according to the present invention is a method for producing a non-aqueous electrolyte battery having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, and in the non-aqueous electrolyte battery, the negative electrode has a lithium layer with a lithium-aluminum alloy layer formed on its surface, and further has a carbon layer on the lithium-aluminum alloy layer, the carbon layer having a basis weight of 0.15 mg / cm2 or more, and the method includes the steps of laminating an aluminum layer on the surface of the lithium layer, further forming a carbon layer on the surface of the aluminum layer, and causing the lithium layer and the aluminum layer to react each other to form a lithium-aluminum alloy layer on the surface of the lithium layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a non-aqueous electrolyte battery having excellent high-temperature storage characteristics and load characteristics at low temperatures.

Background Art

[0002] Currently, non-aqueous electrolyte batteries such as lithium primary batteries and lithium-ion secondary batteries having a non-aqueous electrolyte are applied in various fields such as power sources for portable devices and applications that are exposed to high temperatures and receive large vibrations, such as power sources for pressure sensors inside tires. However, in response to the expansion of their applications, attempts have been made to improve various characteristics.

[0003] However, when the battery is stored at high temperatures, a reaction occurs between the electrolyte and the electrode, causing problems such as battery swelling. Therefore, in applications where the battery is used in a high-temperature environment, measures to suppress the reaction between the electrolyte and the electrode are required.

[0004] On the other hand, sulfur-based compounds such as propane sultone are known as additives that can suppress the reaction with the electrolyte and suppress the swelling of the battery during high-temperature storage by forming a film on the surface of the positive electrode or the negative electrode (Patent Document 1).

[0005] Further, Patent Document 2 discloses that by using a non-aqueous electrolyte containing lithium bisoxalate borate [LiB(C2O4)2] and LiBF4 in a molar ratio range of 2:8 to 5:5, an increase in internal resistance caused by moisture released from the positive electrode active material into the electrolyte at high temperatures and an increase in internal pressure due to decomposition of the electrolyte can be prevented, and a battery with excellent characteristics at both low and high temperatures can be constructed.

[0006] However, when additives such as propane sultone and lithium bis(oxalato)borate are contained in the electrolyte solution to produce a sufficient effect, for example, the film formed on the surface of the negative electrode inhibits the discharge reaction, increasing the internal resistance of the battery, and thus the discharge characteristics tend to deteriorate after high-temperature storage.

[0007] On the other hand, in Patent Documents 3 and 4, as a method alternative to the above additives, it has been proposed to form a layer containing carbon on the surface of the negative electrode.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, non-aqueous electrolyte batteries are required to have battery characteristics that can be used in a wide temperature environment including not only high temperatures but also low temperatures. In order to achieve both high-temperature storage characteristics and low-temperature load characteristics, further studies are needed.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a non-aqueous electrolyte battery having excellent high-temperature storage characteristics and load characteristics at low temperatures.

Means for Solving the Problems

[0011] The manufacturing method of the non-aqueous electrolyte battery of the present invention is a method for manufacturing a non-aqueous electrolyte battery having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. In the non-aqueous electrolyte battery, the negative electrode has a lithium layer with a lithium-aluminum alloy layer formed on its surface, and further has a carbon layer on the lithium-aluminum alloy layer. The basis weight of the carbon layer is 0.15 mg / cm 2 or more, and includes a step of laminating an aluminum layer on the surface of the lithium layer, a step of further forming a carbon layer on the surface of the aluminum layer, and a step of reacting the lithium layer and the aluminum layer to form a lithium-aluminum alloy layer on the surface of the lithium layer.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a manufacturing method of a non-aqueous electrolyte battery excellent in high-temperature storage characteristics and load characteristics at low temperatures.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0014] The non-aqueous electrolyte battery of the present invention contains a negative electrode having a lithium layer with a lithium-aluminum alloy layer formed on its surface, and further having a carbon layer on the lithium-aluminum alloy layer. Although the reason is not clear, by using the above negative electrode, the deterioration of the battery characteristics during high-temperature storage is suppressed, and the load characteristics of the non-aqueous electrolyte battery at low temperatures after high-temperature storage (for example, the load characteristics at low temperatures of about -40°C) can be improved.

[0015] The lithium-aluminum alloy layer of the negative electrode can be formed, for example, by providing an aluminum layer composed of an aluminum foil or an aluminum alloy foil on the surface of a lithium layer composed of a lithium foil or a lithium alloy foil to form a laminate, and further forming a carbon layer on the surface of the aluminum layer in the laminate (the surface opposite to the lithium layer), and bringing the laminate for the negative electrode into contact with a non-aqueous electrolyte to react the lithium layer and the aluminum layer.

[0016] When forming the lithium-aluminum alloy layer by bringing the laminate for the negative electrode into contact with a non-aqueous electrolyte, this may be carried out before battery assembly. In this case, the negative electrode obtained by changing the aluminum layer of the laminate for the negative electrode into a lithium-aluminum alloy layer will be used for the assembly of a non-aqueous electrolyte battery. On the other hand, a battery can also be assembled using the laminate for the negative electrode instead of the negative electrode, and when assembling the battery, the laminate for the negative electrode is brought into contact with a non-aqueous electrolyte to form a lithium-aluminum alloy layer in the same manner as above to obtain a negative electrode. In this case, since the manufacturing process of the negative electrode before battery assembly can be simplified, it is preferable in terms of further enhancing the productivity of the battery.

[0017] Examples of the lithium foil or lithium alloy foil for forming the lithium layer include a foil composed of Li (and inevitable impurities) (lithium foil), and a foil composed of a Li alloy containing a total of 40% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less of alloy components such as Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, and Mo, with the balance being Li and inevitable impurities.

[0018] The thickness of the lithium foil or lithium alloy foil for forming the lithium layer is preferably 0.1 to 1.5 mm.

[0019] Examples of the aluminum foil or aluminum alloy foil for forming the aluminum layer include a foil made of Al (and inevitable impurities) (aluminum foil), and an aluminum alloy containing alloy components such as Fe, Ni, Co, Mn, Cr, V, Ti, Zr, Nb, Mo, with the balance being Al and inevitable impurities (the total content of the alloy components is, for example, 50% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less), and a foil made of such an aluminum alloy (aluminum alloy foil).

[0020] The thickness of the aluminum foil or aluminum alloy foil for forming the aluminum layer is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 5 μm or more in order to clarify the effect of the present invention by forming the lithium-aluminum alloy layer.

[0021] On the other hand, if the ratio of the lithium-aluminum alloy layer to the lithium layer becomes too large, it will cause a decrease in the capacity of the negative electrode. In addition, due to the volume expansion when the aluminum layer alloyizes with lithium, cracks occur in the aluminum layer (aluminum alloy layer). However, if the thickness of the aluminum layer is too thick, the cracks will occur deep inside the negative electrode, and there is a risk that a part of the aluminum alloy layer will fall off when subjected to large vibrations. Therefore, the thickness of the aluminum foil or aluminum alloy foil is preferably 20 μm or less, more preferably 15 μm or less, so that the thickness of the formed lithium-aluminum alloy layer is below a certain level.

[0022] Note that the aluminum alloy layer does not necessarily need to be formed on the entire surface of the lithium layer, and it may be formed on a part of the surface of the lithium layer. However, since the effect of the present invention is more likely to occur as the ratio of the area where the aluminum alloy layer is formed increases, the ratio of the area where the aluminum alloy layer is formed on the surface of the lithium layer is preferably 40% or more, more preferably 70% or more, and most preferably 100%, that is, the aluminum alloy layer is formed on the entire surface of the lithium layer.

[0023] The aluminum layer can be formed on one or both sides of the lithium layer according to the form of the battery. For example, in a battery where the positive electrodes are arranged on both sides of the lithium layer of the negative electrode, aluminum layers can be provided on both sides of the lithium layer to form a lithium-aluminum alloy layer.

[0024] The laminate having a lithium layer and an aluminum layer can be formed by laminating and pressing a lithium foil or a lithium alloy foil for constituting the lithium layer and an aluminum foil or an aluminum alloy foil for constituting the aluminum layer.

[0025] The carbon layer of the negative electrode may be composed only of carbon (its particles), or may contain a binder together with carbon.

[0026] Examples of the carbon constituting the carbon layer include carbon blacks such as furnace black, channel black, acetylene black, and thermal black; graphites such as natural graphite (flake graphite, etc.) and artificial graphite; etc. Only one of these may be used, or two or more of them may be used in combination.

[0027] In addition, examples of the binder that can be used for the carbon layer include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyvinylpyrrolidone, etc. In particular, a compound having a 5-membered lactam structure such as polyvinylpyrrolidone is preferably used because it can disperse fine carbon materials such as carbon black well in a state dissolved in a solvent.

[0028] The content of the binder in the carbon layer is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

[0029] The basis weight of the carbon layer in the negative electrode is preferably 0.15 mg / cm 2 or more, more preferably 0.3 mg / cm 2 or more, and particularly preferably 0.5 mg / cm 2 or more. However, even if the carbon layer is thickened, the effect may saturate, and the entire negative electrode may become thick, for example, reducing the amount of the positive electrode active material that can be introduced into the battery, which may cause a decrease in the battery capacity. Therefore, from the viewpoint of increasing the battery capacity, for example, the basis weight of the carbon layer in the negative electrode is preferably 1.5 mg / cm 2 or less, and more preferably 1.0 mg / cm 2 or less.

[0030] Note that the carbon layer does not have to be formed on the entire surface of the aluminum alloy layer, and the carbon layer may be formed on a part of the surface of the aluminum alloy layer. That is, a part of the aluminum alloy layer may not be covered with the carbon layer and may be exposed on the surface of the negative electrode. For example, when the lithium-aluminum alloy layer is formed, its surface may be uneven, and the convex portion may be exposed on the surface of the negative electrode. Also, there may be a portion where the aluminum alloy layer is not formed directly on the carbon layer is formed on a part of the surface of the lithium layer.

[0031] However, as the ratio of the area of the portion where the aluminum alloy layer and the carbon layer are formed on the lithium layer increases, the effect of the present invention is more likely to occur. Therefore, the ratio of the area where the carbon layer is formed on the surface of the aluminum alloy layer is preferably 40% or more, more preferably 70% or more, and particularly preferably 100%, that is, the carbon layer is formed on the entire surface of the aluminum alloy layer.

[0032] Furthermore, it is most preferable that the aluminum alloy layer is formed on the entire surface of the lithium layer, and the carbon layer is formed on the entire surface of the aluminum alloy layer.

[0033] The carbon layer can be formed by a method in which a composition for forming a carbon layer (a liquid composition such as a paste or a slurry), which is prepared by dispersing carbon, for example, and a binder added as necessary (the binder may be dissolved) in an organic solvent, is applied to the surface of the aluminum layer in a laminate having a lithium layer and an aluminum layer, and then dried.

[0034] As the organic solvent used in the composition for forming a carbon layer, a solvent used in the non-aqueous electrolyte of the battery is preferably used. Specific examples thereof 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; ethers such as 1,2-dimethoxyethane (DME), diglyme (diethylene glycol dimethyl ether), triglyme (triethylene glycol dimethyl ether), tetraglyme (tetraethylene glycol dimethyl ether), methoxyethoxyethane, 1,2-diethoxyethane, and tetrahydrofuran; cyclic esters such as γ-butyrolactone; nitriles; and the like. One or more of these can be used. However, since carbonates such as propylene carbonate react with lithium to form lithium carbonate and may reduce the reactivity of the negative electrode surface, from the viewpoint of more easily exhibiting the effects of the present invention, it is preferable to use a solvent other than carbonate, more preferably an ether, and even more preferably DME.

[0035] In addition, as the organic solvent used in the composition for forming a carbon layer, a solvent used when forming a paint such as a slurry having a positive electrode active material can also be used. When using a fine carbon material such as carbon black, compounds having a 5-membered lactam structure such as 2-pyrrolidone and N-methyl-2-pyrrolidone (NMP) are preferably used because they can disperse the carbon material well. The compound having a 5-membered lactam structure can also be used by mixing it with the solvent used in the non-aqueous electrolyte.

[0036] The negative electrode can be composed of only a lithium layer, a lithium-aluminum alloy layer, and a carbon layer, but may further have a current collector as needed.

[0037] Examples of the negative electrode current collector include those made of copper, nickel, iron, and stainless steel. Examples of its form include plain woven wire mesh, expanded metal, lath mesh, punched metal, metal foam, foil (sheet), etc. The thickness of the current collector is preferably, for example, 5 to 100 μm. It is also desirable to apply a paste-like conductive material such as carbon paste or silver paste to the surface of such a current collector.

[0038] For the positive electrode of a non-aqueous electrolyte battery, for example, a molded body obtained by molding a mixture (positive electrode mixture) containing a positive electrode active material, a conductive assistant, a binder, etc. into a pellet shape, etc., or a structure having a layer (positive electrode mixture layer) made of the positive electrode mixture on one or both sides of a current collector can be used.

[0039] Examples of the positive electrode active material include manganese dioxide, lithium-containing manganese oxides [for example, LiMn3O6 and composite oxides having the same crystal structure as manganese dioxide (such as β-type, γ-type, or a structure in which β-type and γ-type are mixed), and the content of Li is 3.5% by mass or less, preferably 2% by mass or less, more preferably 1.5% by mass or less, and particularly preferably 1% by mass or less], Li a Ti 5 / 3 -containing composite oxides such as O4 (4 / 3 ≤ a < 7 / 3); vanadium oxides; niobium oxides; titanium oxides; sulfides such as iron disulfide; graphite fluoride; etc.

[0040] Examples of the conductive assistant for the positive electrode mixture include, for example, flaky graphite, acetylene black, ketjen black, carbon black, etc. Only one of these may be used, or two or more may be used in combination.

[0041] Furthermore, examples of the binder for the positive electrode active material include fluororesins such as PVDF, PTFE, and polymers of hexafluoropropylene. Only one of these may be used, or two or more may be used in combination.

[0042] In the case of a molded body of the positive electrode active material, for example, the positive electrode can be manufactured by pressure-molding a positive electrode active material prepared by mixing a positive electrode active material, a conductive assistant, a binder, etc. into a predetermined shape.

[0043] In the case of a positive electrode having a positive electrode active material layer and a current collector, for example, a positive electrode active material, a conductive assistant, a binder, etc. are dispersed in water or an organic solvent such as N-methyl-2-pyrrolidone (NMP) to prepare a positive electrode active material-containing composition (such as a slurry or a paste) (the binder may be dissolved in the solvent), and this is applied onto the current collector and dried, and can be manufactured through a process of performing a pressing process such as a calendering process as necessary.

[0044] However, the positive electrode is not limited to those manufactured by the above-described methods, and those manufactured by other methods may also be used.

[0045] As the composition in the positive electrode active material related to the positive electrode, the amount of the positive electrode active material is preferably 80 to 90% by mass, the content of the conductive assistant is preferably 1.5 to 10% by mass, and the content of the binder is preferably 0.3 to 10% by mass.

[0046] In the case of a molded body of the positive electrode active material, its thickness is preferably 0.15 to 4 mm. On the other hand, in the case of a positive electrode having a positive electrode active material layer and a current collector, the thickness of the positive electrode active material layer (the thickness per side of the current collector) is preferably 30 to 300 μm.

[0047] When using a current collector for the positive electrode, examples of the current collector include those made of stainless steel such as SUS316, SUS430, and SUS444. Examples of its form include plain woven wire mesh, expanded metal, lath mesh, punched metal, metal foam, foil (plate), etc. The thickness of the current collector is preferably, for example, 0.05 to 0.2 mm. It is also desirable to apply a paste-like conductive material such as carbon paste or silver paste to the surface of such a current collector.

[0048] The non-aqueous electrolyte battery of the present invention is assembled using, for example, a laminate (laminated electrode body) in which the negative electrode and the positive electrode are laminated via a separator, a wound body (wound electrode body) obtained by winding this laminate in a spiral shape, and further a flat wound body (flat wound electrode body) formed by shaping this wound body so that its cross section is flat. Also, a non-aqueous electrolyte battery of the present invention can be assembled by using a positive electrode composed of a molded body of a positive electrode mixture and the negative electrode, and accommodating them in a flat battery case with a separator interposed therebetween.

[0049] Also, a battery can be assembled using the laminate for negative electrode instead of the negative electrode, and the negative electrode can be formed during the assembly.

[0050] Nonwoven fabrics or microporous membranes (microporous films) are used as separators. As the material, polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers can be used. In addition, when heat resistance is required in relation to the use of the battery, fluororesins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polymethylpentene, polyamide, polyimide, aramid, cellulose, etc. can also be used. The material of the nonwoven fabric or microporous membrane may use only one of the above-exemplified ones, or two or more of them. Further, the nonwoven fabric or microporous membrane serving as the separator may be of a single-layer structure composed of the above-exemplified materials, or, for example, a laminated structure in which a plurality of nonwoven fabrics or microporous membranes composed of different materials are laminated can also be used.

[0051] From the viewpoint of suppressing the decrease in the energy density of the battery, the thickness of the separator may be, for example, 500 μm or less, preferably 450 μm or less, and more preferably 300 μm or less. However, if the separator is too thin, the function of preventing short circuit may decrease. Therefore, when using a nonwoven fabric, the thickness may be, for example, 30 μm or more, preferably 100 μm or more, and more preferably 150 μm or more. Also, when using a microporous membrane, it is preferably 10 μm or more, and more preferably 15 μm or more.

[0052] Examples of the non-aqueous electrolyte for a non-aqueous electrolyte battery include those prepared by dissolving LiPF6, LiBF4, LiClO4, LiCF3SO3, etc. as electrolytes in an organic solvent. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate; ethers such as 1,2-dimethoxyethane, diglyme (diethylene glycol dimethyl ether), triglyme (triethylene glycol dimethyl ether), tetraglyme (tetraethylene glycol dimethyl ether), methoxyethoxyethane, 1,2-diethoxyethane, tetrahydrofuran; cyclic esters such as γ-butyrolactone; mononitriles such as acetonitrile, propionitrile; etc. One or more of these can be used. In particular, it is preferable to use the above-mentioned carbonate and ether in combination.

[0053] When using carbonate and ether in combination as the non-aqueous electrolyte solvent, the volume ratio of carbonate to ether in the total solvent is preferably carbonate:ether = 30:70 to 70:30.

[0054] The concentration of the electrolyte in the non-aqueous electrolyte is preferably 0.3 to 1.5 mol / l.

[0055] Furthermore, additives can be contained in the non-aqueous electrolyte as needed to improve storage characteristics at high temperatures, etc. Examples of usable additives include saturated sultone compounds such as 1,3-propane sultone, 1,4-butane sultone; unsaturated sultone compounds such as 1,3-propene sultone; acid anhydrides such as maleic anhydride, phthalic anhydride; organic boron lithium salts such as LiB(C2O4)2; dinitriles such as malononitrile, succinonitrile, glutaronitrile, adiponitrile; etc. One or more of these can be used.

[0056] The content of the additive in the non-aqueous electrolyte is preferably, for example, 0.1% by mass or more, more preferably 0.3% by mass or more, and particularly preferably 0.5% by mass or more. On the other hand, if the content of the additive becomes too large, there is a risk that the internal resistance of the battery increases and the discharge characteristics deteriorate. Therefore, the content of the additive in the non-aqueous electrolyte is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1.5% by mass or less.

[0057] There is no particular limitation on the form of the non-aqueous electrolyte battery, and it can be in various forms such as flat (including coin-shaped and button-shaped), laminated, and cylindrical [cylindrical, square (square cylindrical)]. Further, as the exterior body (battery case) that houses the negative electrode, positive electrode, separator, and non-aqueous electrolyte inside, a metal can (outer can) with an opening and a lid (sealed can) can be used in combination, or a metal laminate film can be used.

[0058] Specifically, a flat or cylindrical battery can be manufactured by caulking and sealing the outer can and the sealed can through a gasket, or by welding and sealing the outer can and the sealed can. A laminated battery can be manufactured by overlapping two metal laminate films or by bending a single metal laminate film and bonding the periphery to seal it.

[0059] When using an exterior body in a form where caulking and sealing is performed, materials for the gasket interposed between the outer can and the sealed can include PP, nylon, etc. In addition, when particularly high heat resistance is required in relation to the use of the battery, heat-resistant resins such as fluororesins like PFA, polyphenylene ether (PEE), polysulfone (PSF), polyarylate (PAR), polyethersulfone (PES), PPS, and PEEK with a melting point or thermal decomposition temperature of 200°C or higher can also be used. Also, when the battery is applied to applications that require heat resistance, a glass hermetic seal can also be used for its sealing.

Examples

[0060] Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

[0061] (Example 1) <Fabrication of the positive electrode> A positive electrode mixture prepared by mixing manganese dioxide as a positive electrode active material, carbon black as a conductive assistant, and PTFE as a binder at a mass ratio of 90:5:5 was molded to obtain a positive electrode (positive electrode mixture molded body) with a diameter of 16 mm and a thickness of 1.8 mm.

[0062] <Fabrication of the negative electrode laminate> An aluminum foil with a thickness of 9 μm was pressure-bonded to one side of a lithium foil with a thickness of 1.2 mm, and this was punched into a circle with a diameter of 16 mm to obtain a laminate of a lithium layer and an aluminum layer.

[0063] Next, acetylene black was dispersed in propylene carbonate to prepare a composition for forming a carbon layer (slurry), and the slurry was applied onto the aluminum layer of the laminate and dried, whereby a negative electrode laminate in which a carbon layer made of acetylene black was formed on the entire surface of the aluminum layer of the laminate was prepared. The basis weight of the carbon layer was 0.5 mg / cm 2 and it was.

[0064] <Preparation of the non-aqueous electrolyte> LiClO4 was dissolved in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane mixed at a volume ratio of 1:1 at a concentration of 0.5 mol / l, and further 1,3-propanesultone: 2% by mass was added to prepare a non-aqueous electrolyte.

[0065] <Assembly of the battery> Using the above positive electrode, negative electrode laminate, and non-aqueous electrolyte, and using a non-woven fabric made of polymethylpentene (thickness: 320 μm) as a separator, a coin-shaped non-aqueous electrolyte primary battery with a diameter of 20 mm and a height of 3.2 mm was assembled in the structure shown in FIG. 1.

[0066] When the laminate for the negative electrode comes into contact with the non-aqueous electrolyte, a lithium-aluminum alloy layer is formed on the surface of the lithium layer in the battery, and a negative electrode having a carbon layer is further formed on the lithium-aluminum alloy layer.

[0067] (Example 2) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that the basis weight of the carbon layer on the surface of the laminate for the negative electrode was 0.02 mg / cm 2 .

[0068] (Example 3) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that the basis weight of the carbon layer on the surface of the laminate for the negative electrode was 0.2 mg / cm 2 .

[0069] (Example 4) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that the basis weight of the carbon layer on the surface of the laminate for the negative electrode was 1 mg / cm 2 .

[0070] (Example 5) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that a slurry in which acetylene black was dispersed in 1,2-dimethoxyethane was prepared and the carbon layer was formed using the slurry.

[0071] (Example 6) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 5, except that the basis weight of the carbon layer on the surface of the laminate for the negative electrode was 0.02 mg / cm 2 .

[0072] (Example 7) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 5, except that the basis weight of the carbon layer on the surface of the laminate for the negative electrode was 0.2 mg / cm 2 .

[0073] (Example 8) The basis weight of the carbon layer on the surface of the laminate for the negative electrode was 1 mg / cm 2 A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 5, except for the above.

[0074] (Comparative Example 1) A slurry prepared in Example 1 was applied to one side of a lithium foil with a thickness of 1.2 mm and dried to produce a laminate of a lithium layer and a carbon layer in which a carbon layer was formed over the entire one side of the lithium layer. The basis weight of the carbon layer was 0.5 mg / cm 2 A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that the laminate was used instead of the laminate for the negative electrode of Example 1.

[0075] (Comparative Example 2) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Comparative Example 1, except that the slurry prepared in Example 5 was used for forming the carbon layer.

[0076] (Comparative Example 3) A coin-shaped non-aqueous electrolyte primary battery was assembled in the same manner as in Example 1, except that the composition for forming a carbon layer was not applied to the surface of the laminate of the lithium layer and the aluminum layer, and the laminate was used as it was for assembling the battery.

[0077] Each of the batteries of Examples 1 to 8 and Comparative Examples 1 to 3 was held in a thermostat at -40°C. After the temperature of the battery dropped, it was discharged at a current value of 10 mA, and the discharge voltage (CCV) of the battery 8 m seconds after the start of discharge was measured to evaluate the load characteristics at low temperature before storage.

[0078] Separately from the above evaluation, each of the batteries of Examples 1 to 8 and Comparative Examples 1 to 3 was stored in a high-temperature environment at 120°C for 500 hours, and then the discharge voltage of the battery was measured in the same manner as above to evaluate the load characteristics at low temperature after high-temperature storage. The respective measurement results are shown in Table 1 and Figure 2.

[0079]

Table 1

[0080] As shown by the results in FIG. 2, in the batteries of Examples 1 to 4 in which a lithium-aluminum alloy layer was formed on the surface of the lithium layer of the negative electrode and a carbon layer was further formed on the lithium-aluminum alloy layer, and the batteries of Examples 5 to 8, in both cases before storage and after high-temperature storage, the higher the basis weight of the carbon layer, the higher the discharge voltage of the battery, and the load characteristics at low temperature could be improved.

[0081] Also, the batteries of Examples 5 to 8 using DME as the solvent of the carbon layer-forming composition could have a higher discharge voltage than the batteries of Examples 1 to 4 using PC, and furthermore, the decrease in the discharge voltage due to high-temperature storage could be more suppressed. This is presumably because the carbon layer-forming composition using DME as the solvent had better carbon dispersibility and could form a homogeneous carbon layer, and problems such as the formation of lithium carbonate when using PC as the solvent did not occur.

[0082] On the other hand, in the batteries of Comparative Examples 1 and 2 in which a carbon layer was directly formed on the surface of the lithium layer, even when the basis weight of the carbon layer was increased to 0.5 mg / cm 2 the decrease in the discharge voltage due to high-temperature storage became as large as about 1 V. Also, for the battery of Comparative Example 3 in which a lithium-aluminum alloy layer was formed on the surface of the lithium layer but no carbon layer was formed thereon, similarly, the decrease in the discharge voltage due to high-temperature storage became as large as about 1 V.

[0083] In the battery of the present invention, as shown in Table 1, by forming a lithium-aluminum alloy layer between the lithium layer and the carbon layer, even when the basis weight of the carbon layer is reduced, the decrease in the discharge voltage due to high-temperature storage can be sufficiently suppressed.

[0084] The present invention can also be implemented in other forms without departing from the gist thereof. The embodiments disclosed in this application are merely examples, and the present invention is not limited to these embodiments. The scope of the present invention is interpreted preferentially based on the description of the appended claims rather than the description in the above specification, and all modifications within the scope equivalent to the claims are included in the claims.

Industrial Applicability

[0085] The non-aqueous electrolyte battery of the present invention mainly takes the form of a primary battery, but can also take the form of a secondary battery, and can be applied to various applications in which conventionally known non-aqueous electrolyte primary batteries and non-aqueous electrolyte secondary batteries are adopted.

Explanation of Reference Numerals

[0086] 1 Non-aqueous electrolyte battery 2 Positive electrode 3 Negative electrode 4 Separator 5 Outer can 6 Sealing can 7 Insulating gasket

Claims

1. A method for manufacturing a non-aqueous electrolyte battery having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, comprising: The non-aqueous electrolyte battery has a negative electrode having a lithium layer with a lithium-aluminum alloy layer formed on its surface, and further has a carbon layer on the lithium-aluminum alloy layer, and the basis weight of the carbon layer is 0.15 mg / cm ２ or more, a step of laminating an aluminum layer on the surface of a lithium layer; a step of further forming a carbon layer on the surface of the aluminum layer; a step of reacting the lithium layer and the aluminum layer to form a lithium-aluminum alloy layer on the surface of the lithium layer. The method for manufacturing a non-aqueous electrolyte battery is characterized by having these steps.

2. The basis weight of the carbon layer is 1.5 mg / cm ２ The method for manufacturing a non-aqueous electrolyte battery according to claim 1, wherein the basis weight is 1.5 mg / cm or less.

3. The method for manufacturing a non-aqueous electrolyte battery according to claim 1 or 2, wherein a liquid composition in which carbon particles are dispersed in an organic solvent is applied to the surface of the aluminum layer and dried to form the carbon layer.

4. The method for manufacturing a non-aqueous electrolyte battery according to claim 3, wherein the liquid composition contains ether as the organic solvent.

5. The method for manufacturing a non-aqueous electrolyte battery according to claim 4, wherein the ether is 1,2-dimethoxyethane.

6. The method for manufacturing a non-aqueous electrolyte battery according to any one of claims 1 to 5, wherein the carbon layer contains carbon black or graphite.

7. The method for manufacturing a non-aqueous electrolyte battery according to any one of claims 1 to 6, wherein the carbon layer contains a binder.

8. The method for manufacturing a non-aqueous electrolyte battery according to any one of claims 1 to 7, wherein the positive electrode contains manganese dioxide or a lithium-containing manganese oxide having the same crystal structure as manganese dioxide and a Li content of 3.5% by mass or less as a positive electrode active material.

9. In the step of laminating an aluminum layer on the surface of a lithium layer, an aluminum alloy layer is laminated on the surface of the lithium layer as the aluminum layer, The method for manufacturing a non-aqueous electrolyte battery according to any one of claims 1 to 8, wherein the ratio of the area of the portion of the surface of the lithium layer where the aluminum alloy layer is laminated is 40% or more.

10. The method for manufacturing a non-aqueous electrolyte battery according to claim 9, wherein the aluminum alloy layer is laminated on the entire surface of the lithium layer.

11. In the step of laminating an aluminum layer on the surface of a lithium layer, an aluminum alloy layer is laminated on the surface of the lithium layer as the aluminum layer, The method for manufacturing a non-aqueous electrolyte battery according to any one of claims 1 to 10, wherein in the step of further forming a carbon layer on the surface of the aluminum alloy layer, the ratio of the area of the portion of the surface of the aluminum alloy layer where the carbon layer is formed is 70% or more.

12. The method for manufacturing a non-aqueous electrolyte battery according to claim 11, wherein the carbon layer is formed on the entire surface of the aluminum alloy layer.

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