Electrode for non-aqueous secondary battery, method for producing same, and non-aqueous secondary battery

Abstract

Provided is an electrode for a non-aqueous secondary battery, the electrode having a current collector layer, a conductive adhesive layer, and an electrode mixture layer in this order, the electrode mixture layer containing an electrode active material and a binder, the conductive adhesive layer having: a first adhesive layer provided on the current collector layer; and a second adhesive layer provided so as to partially cover the first adhesive layer and in contact with the electrode composite layer, the first adhesive layer including conductive particles and an adhesive material, the second adhesive layer contains conductive particles and an adhesive material, and the content ratio of the conductive particles is lower than that of the first adhesive layer, or the second adhesive layer contains an adhesive material and does not contain conductive particles. The present invention also provides a method for manufacturing an electrode for a non-aqueous secondary battery, and a non-aqueous secondary battery.

Description

TECHNICAL FIELD

[0001] The present application relates to an electrode for a nonaqueous secondary battery and a method for manufacturing the same, and a nonaqueous secondary battery. BACKGROUND

[0002] A nonaqueous secondary battery such as a nonaqueous lithium ion secondary battery generally has an electrode such as a positive electrode and a negative electrode. In addition, an electrode for a nonaqueous secondary battery generally has a current collector and an electrode composite material layer containing an electrode active material provided on the surface of the current collector. Such an electrode is generally formed by a method of preparing a slurry containing a material constituting the electrode composite material layer and a solvent, applying the slurry to the surface of the current collector to form a slurry layer, and further drying the layer.

[0003] However, in recent years, a method of manufacturing an electrode using a dry process using a powder-like material has been attracting attention (Patent Documents 1 to 4).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-108971;

[0007] Patent Document 2: Japanese Patent Application Publication No. 2014-078497 (corresponding publication: U.S. Patent Application Publication No. 2014 / 079872 and U.S. Patent Application Publication No. 2015 / 0194680);

[0008] Patent Document 3: Japanese Patent Application Publication No. 2013-012393 (corresponding publication: U.S. Patent Application Publication No. 2013 / 0004843);

[0009] Patent Document 4: International Publication No. 2015 / 115177. SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION

[0011] In the method of manufacturing an electrode using a dry process, an electrode composite material layer can be manufactured by, for example, piling up composite particles containing an electrode active material and a binder material on a current collector and performing press molding. However, since the adhesion of the composite particles to the current collector is low, the electrode manufactured by the dry process sometimes tends to have a high resistance. In addition, the composite particles piled up on the current collector can arbitrarily move the current collector when press molding is performed, resulting in, for example, a requirement to limit the molding speed in order to mold an electrode composite material layer having a desired thickness by roll molding, and difficulty in improving the productivity.

[0012] For example, Patent Document 1 discloses a conductive adhesive layer containing carbon particles disposed between the current collector and the electrode composite material layer. While this technique achieves low electrode resistance, it is difficult to sufficiently improve the adhesion of the composite particles to the current collector, and it is also difficult to accelerate the forming speed during roll forming. Furthermore, for example, Patent Document 2 discloses a method to improve the adhesion of the composite particles to the current collector by patterning an adhesive material between the current collector and the electrode composite material layer. While this technique can accelerate the forming speed during roll forming, there is a tendency for the resistance between the current collector and the electrode active material to increase.

[0013] Therefore, even with the use of previously known technologies, it is difficult to achieve both low electrode resistance and high-speed molding.

[0014] The present invention was made in view of the above-mentioned actual situation. The object of the present invention is to provide: an electrode for a non-aqueous secondary battery with low resistance and good high-speed formability, which can be manufactured by pressurizing the electrode during electrode forming; a method for manufacturing an electrode for a non-aqueous secondary battery that can accelerate the forming speed and manufacture an electrode with low resistance; and a non-aqueous secondary battery having the above-mentioned electrode for a non-aqueous secondary battery.

[0015] Solution for solving the problem

[0016] The present invention is described below.

[0017] [1] An electrode for a non-aqueous secondary battery, comprising sequentially a current collector layer, a conductive adhesive layer, and an electrode composite material layer, wherein the electrode composite material layer comprises an electrode active material and an adhesive material, and the conductive adhesive layer comprises: a first adhesive layer disposed on the current collector layer; and a second adhesive layer disposed such that it partially covers the first adhesive layer and is in contact with the electrode composite material layer, wherein the first adhesive layer comprises conductive particles and an adhesive material, and the second adhesive layer comprises conductive particles and an adhesive material, and the proportion of the conductive particles is lower than that of the first adhesive layer; or the second adhesive layer comprises an adhesive material but does not contain conductive particles.

[0018] [2] The electrode for a non-aqueous secondary battery according to [1], wherein the electrode composite material layer comprises composite particles containing electrode active material and binder material.

[0019] [3] The electrode for a non-aqueous secondary battery according to [1] or [2], wherein the second adhesive layer comprises an adhesive material and does not contain conductive particles.

[0020] [4] An electrode for a non-aqueous secondary battery according to any one of [1] to [3], wherein the second adhesive layer is regularly disposed on a portion of the surface of the first adhesive layer.

[0021] [5] An electrode for a non-aqueous secondary battery according to any one of [1] to [4], wherein the second adhesive layer is partially disposed on the surface of the current collector layer on the side where the first adhesive layer is disposed.

[0022] [6] The electrode for a non-aqueous secondary battery according to any one of [1] to [5], wherein the area of ​​the first adhesive layer covered by the second adhesive layer is 20% or more and 80% or less relative to the total area of ​​the first adhesive layer.

[0023] [7] An electrode for a non-aqueous secondary battery according to any one of [1] to [6], wherein the thickness t1 of the first adhesive layer is 0.1 μm or more and 3.0 μm or less.

[0024] [8] An electrode for a non-aqueous secondary battery according to any one of [1] to [7], wherein the thickness t2 of the second adhesive layer is 0.1 μm or more and 2.0 μm or less.

[0025] [9] An electrode for a non-aqueous secondary battery according to any one of [1] to [8], wherein the ratio (t2 / t1) of the thickness t2 of the second adhesive layer to the thickness t1 of the first adhesive layer is 0.1 or more and 10 or less.

[0026]

[10] An electrode for a non-aqueous secondary battery according to any one of [1] to [9], wherein the adhesive material included in the second adhesive layer is granular and the median particle size of the adhesive material is 0.1 μm or more and 1 μm or less.

[0027]

[11] An electrode for a non-aqueous secondary battery according to any one of [1] to

[10] , wherein the glass transition temperature Tg1 of the adhesive material included in the first adhesive layer is -30°C or higher and 25°C or lower, and the glass transition temperature Tg2 of the adhesive material included in the second adhesive layer is -50°C or higher and -10°C or lower, wherein Tg1 is greater than Tg2.

[0028]

[12] The electrode for a non-aqueous secondary battery according to any one of [1] to

[11] , wherein the contact adhesion of the surface of the conductive adhesive layer is greater than 0.1N and less than 3.0N.

[0029]

[13] A non-aqueous secondary battery having a positive electrode, a negative electrode and an electrolyte, wherein at least one of the positive electrode and the negative electrode is an electrode for a non-aqueous secondary battery as described in any one of [1] to

[12] .

[0030]

[14] A method for manufacturing an electrode for a non-aqueous secondary battery, wherein the electrode for a non-aqueous secondary battery is any one of [1] to

[12] , the manufacturing method comprising: step (A), wherein a conductive adhesive layer is provided on the current collector layer by performing a step (A1) of providing the first adhesive layer on the current collector layer and a step (A2) of partially providing the second adhesive layer on the first adhesive layer; and step (B), wherein composite particles comprising an electrode active material and a binder material are supplied to the second adhesive layer of the conductive adhesive layer, and pressure is applied to provide an electrode composite material layer.

[0031]

[15] In the method for manufacturing an electrode for a non-aqueous secondary battery according to

[14] , the current collector layer is a strip, and the width S1 of the region on the current collector layer where the first adhesive layer is disposed and the width S2 of the region where the second adhesive layer is disposed satisfy the relationship expressed by the following formula (1).

[0032]

[0033] Invention Effects

[0034] According to the present invention, it is possible to provide: an electrode for a non-aqueous secondary battery with low resistance and good high-speed formability; a method for manufacturing an electrode for a non-aqueous secondary battery that can accelerate the forming speed and produce an electrode with low resistance; and a non-aqueous secondary battery having the above-described electrode for a non-aqueous secondary battery. Attached Figure Description

[0035] Figure 1 This is a schematic cross-sectional view of an electrode according to one embodiment of the present invention.

[0036] Figure 2 This is a schematic cross-sectional view illustrating a conductive adhesive layer according to one embodiment of the present invention.

[0037] Figure 3 This is a top view schematically illustrating a conductive adhesive layer according to one embodiment of the present invention. Detailed Implementation

[0038] The present invention will now be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and can be implemented in any way without departing from the scope of the claims and their equivalents.

[0039] In the following description, in polymers made by copolymerizing multiple monomers, unless otherwise stated, the proportion of monomer units formed by polymerizing a particular monomer in the polymer is generally consistent with the proportion (feed ratio) of that particular monomer in all monomers used in the polymerization of the polymer.

[0040] Furthermore, in the following description, the monomer unit and other molecules or their partial structures are not limited by their manufacturing method. For example, an aromatic vinyl monomer unit is a unit having a structure formed by the polymerization of aromatic vinyl monomers, but aromatic vinyl monomer units also include units having the same structure as those formed by the polymerization of aromatic vinyl monomers, formed by other forming methods.

[0041] [1. Overview of electrodes for non-aqueous secondary batteries]

[0042] Figure 1 This is a schematic cross-sectional view illustrating an electrode for a non-aqueous secondary battery according to one embodiment of the present invention. In the following description, the electrode for a non-aqueous secondary battery will sometimes be simply referred to as an "electrode". Figure 1 As shown, in one embodiment of the present invention, the electrode 10 sequentially comprises a current collector layer 1, a conductive adhesive layer 2, and an electrode composite material layer 3. In the electrode 10, the electrode composite material layer 3 is a layer containing an electrode active material and an adhesive material.

[0043] In addition, such as Figure 1 As shown, in electrode 10, the conductive adhesive layer 2 comprises: a first adhesive layer 21 disposed on current collector layer 1; and a second adhesive layer 22 disposed such that it partially covers the first adhesive layer 21 and is in contact with electrode composite material layer 3. The first adhesive layer 21 is a layer comprising conductive particles and a binder material. Furthermore, the second adhesive layer 22 is any one of the layers having a configuration as shown in (a) or (b).

[0044] (a) A layer containing conductive particles and a binder material, wherein the proportion of conductive particles is lower than that of the first adhesive layer 21.

[0045] (b) A layer containing a binding material but not conductive particles.

[0046] When the second adhesive layer of the conductive adhesive layer 2 is any one of the layers having the above-described (a) or (b) configuration, the proportion of adhesive material in the second adhesive layer is generally higher than the proportion of adhesive material in the first adhesive layer.

[0047] According to the present invention, by having a conductive adhesive layer, wherein the conductive adhesive layer has a first adhesive layer and a second adhesive layer, an electrode with reduced resistance and good high-speed formability can be manufactured.

[0048] In one embodiment of the electrode of the present invention, the inventors speculate on the mechanism by which both reduced electrode resistance and high-speed molding are achieved. However, the scope of the present invention is not limited to the mechanism described below.

[0049] Electrodes with an electrode composite material layer typically formed by pressurizing composite particles containing electrode active material and binder material in a dry process tend to have high contact resistance between the current collector layer and the electrode active material in the electrode composite material layer. In contrast, the electrode of this embodiment has a structure in which, in the conductive adhesive layer, in areas where a second adhesive layer is not provided, the current collector layer and the electrode composite material layer are stacked with a first adhesive layer containing conductive particles in between. In this stacked structure, the contact resistance between the electrode active material in the electrode composite material layer and the first adhesive layer can be sufficiently reduced, as can the contact resistance between the first adhesive layer and the current collector layer. Therefore, the inventors hypothesize that the electrode of this embodiment, by having a first adhesive layer in between in areas where a second adhesive layer is not provided, can sufficiently reduce the resistance between the current collector layer and the electrode active material in the electrode composite material layer, and thus, even with a partial provision of a second adhesive layer, the overall resistance of the electrode can be reduced.

[0050] Furthermore, the inventors speculate that by providing a second adhesive layer on the first adhesive layer with a higher proportion of adhesive material than the first adhesive layer, the electrode of this embodiment can sufficiently increase the friction coefficient of the conductive adhesive layer surface. Therefore, when supplying composite particles to the conductive adhesive layer surface and applying pressure, the movement of the composite particles is restricted, and even if the pressure molding speed (molding speed) is accelerated, the electrode composite material layer can be molded to the desired thickness.

[0051] Furthermore, during their research on the electrode of this embodiment, the inventors unexpectedly discovered that the electrode of this embodiment can improve the high-temperature storage performance of non-aqueous secondary batteries. The inventors hypothesize the mechanism as follows. However, the scope of the present invention is not limited to the mechanism described below.

[0052] Conductive particles are substances that can reduce the resistance between the current collector layer and the electrode active material, but they are also presumed to be a major cause of degradation in non-aqueous secondary batteries (e.g., the starting point for degradation of the electrode active material or electrolyte at high temperatures). In contrast, in this embodiment, a portion of the adhesive material in the second adhesive layer disposed on the first adhesive layer penetrates into the first adhesive layer, covering a portion of the surface of the conductive particles. The inventors speculate that, as a result, the conductive adhesive layer can utilize the surface of the conductive particles covered by the adhesive material to a degree that can suppress the degradation of the non-aqueous secondary battery while maintaining good conductivity between the current collector layer and the electrode active material in the electrode composite layer, thus improving the high-temperature storage performance of the non-aqueous secondary battery.

[0053] The structure of each electrode in this embodiment will be described below.

[0054] [2. Current collector layer]

[0055] As the material for the current collector layer, materials that are both conductive and electrochemically durable are preferred. Specific examples of materials that can be used in the current collector layer include metals, carbon, and conductive polymers, with metals being preferred. Examples of metals include copper, aluminum, platinum, nickel, tantalum, titanium, stainless steel, and their alloys; copper, aluminum, and aluminum alloys are particularly preferred from the perspective of conductivity and voltage resistance. When high voltage resistance is required, high-purity aluminum disclosed in Japanese Patent Application Publication No. 2001-176757 is preferred. Aluminum is particularly preferred as a current collector layer material that can be used in the positive electrode, and copper is particularly preferred as a current collector layer material that can be used in the negative electrode. These materials can be used individually or in combination of two or more.

[0056] The current collector layer typically has a film-like or sheet-like shape. The thickness of the current collector layer can be appropriately selected according to the intended use, preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0057] [3. Conductive adhesive layer]

[0058] The conductive adhesive layer has: a first adhesive layer disposed on the current collector layer; and a second adhesive layer disposed such that it partially covers the first adhesive layer and is in contact with the electrode composite material layer.

[0059] [3.1. First adhesive layer]

[0060] The first adhesive layer is a layer disposed on the current collector layer and comprising at least conductive particles and adhesive material.

[0061] The conductive particles that can be included in the first adhesive layer are particles made of conductive materials. Examples of conductive particles include metal particles and carbon particles. Carbon particles are particularly preferred because they can effectively reduce the resistance between the current collector layer and the electrode active material. Furthermore, when carbon particles are included, the high-temperature storage performance of non-aqueous secondary batteries tends to decrease. Therefore, even when carbon particles are included, non-aqueous secondary batteries with good high-temperature storage performance can be manufactured.

[0062] Examples of carbon particles include: graphite (specifically, natural graphite, synthetic graphite, etc.) which has high conductivity due to the presence of delocalized π electrons; carbon black (specifically, acetylene black, Ketjen black, other furnace blacks, channel blacks, pyrolysis blacks, etc.) which are spherical aggregates formed by the aggregation of multiple layers of graphitic carbon microcrystals to create a disordered layer structure; carbon fibers, carbon whiskers, etc. Among these, graphite or carbon black is particularly preferred from the perspective of high-density filling of the first binder layer, reducing electron mobility resistance, and further reducing the internal resistance of non-aqueous secondary batteries. Furthermore, the carbon particles described above can be used alone or in combination of two or more.

[0063] The median particle size of the conductive particles is, for example, 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.3 μm or more, for example, 10 μm or less, preferably 8 μm or less, more preferably 6 μm or less. The median particle size of the conductive particles can be determined by measuring the particle size using a laser diffraction particle size distribution measuring device (SALD-3100; manufactured by Shimadzu Corporation), and determining the particle size (D50) as the cumulative volume calculated from the smallest particle size side in the obtained particle size distribution (volume basis).

[0064] The proportion of conductive particles in the first adhesive layer is typically 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and typically 99.9% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, relative to the solid content contained in the first adhesive layer.

[0065] The adhesive material that the first adhesive layer can contain is a compound capable of bonding conductive particles together and bonding conductive particles to the current collector layer. Polymers are typically used as such adhesive materials. The polymer used as the adhesive material can be a water-insoluble polymer. Unless otherwise specified, "water-insoluble" means that when 0.5g of the polymer is dissolved in 100g of water at 25°C, the insoluble component is 90% by mass or more. Preferred examples of adhesive materials include acrylate polymers, conjugated diene polymers, and fluorinated polymers, with acrylate polymers and conjugated diene polymers being particularly preferred. This is because they can improve voltage withstand and increase the energy density of non-aqueous secondary batteries. Furthermore, they also offer excellent adhesion.

[0066] Acrylic polymers are polymers containing monomer units (hereinafter sometimes referred to as "acrylate monomer units") having the following structure, which is a general formula (1): CH2=CR 1 -COOR 2 (where R is in the formula) 1 R represents a hydrogen atom or a methyl group.2 Indicates alkyl or cycloalkyl, R 2 It can also be formed by polymerizing monomers [(meth)acrylates] having ether, hydroxyl, phosphate, amino, carboxyl, fluorine or epoxy groups. Specifically, the acrylate polymer can be a homopolymer of monomers represented by general formula (1), or a copolymer obtained by polymerizing a mixture of monomers containing monomers represented by the above general formula (1). Specific examples of the monomeric compounds represented by general formula (1) include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, hexyl methacrylate, nonyl methacrylate, octyl methacrylate, isooctyl methacrylate, isobornyl methacrylate, isodecanyl methacrylate, lauryl methacrylate, stearyl methacrylate, and alkyl methacrylates such as tridecyl methacrylate; butoxyethyl methacrylate, ethoxydiethylene glycol methacrylate, and propyl methacrylate. (Methacrylic acid dipropylene glycol ester, (meth)acrylate methoxy polyethylene glycol ester, (meth)acrylate phenoxyethyl ester, (meth)acrylate tetrahydrofuran ester, etc., containing ether groups; (meth)acrylate 2-hydroxyethyl ester, (meth)acrylate 2-hydroxypropyl ester, (meth)acrylate 2-hydroxy-3-phenoxypropyl ester, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, etc., containing hydroxyl groups; (meth)acrylate 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl phthalate, etc., containing carboxylic acid groups; (meth)acrylate perfluorooctyl ethyl ester, etc., containing fluorine groups; (meth)acrylate ethyl phosphate, etc., containing phosphate groups; (meth)acrylate glycidyl ester, etc., containing epoxy groups; (meth)acrylate dimethylaminoethyl ester, etc., containing amino groups. In this specification, the term "(meth)acrylic acid" includes both "acrylic acid" and "methacrylic acid". Furthermore, the term "(meth)acryloyl" includes both "acryloyl" and "methacryloyl".

[0067] The monomers represented by general formula (1) can be used alone or in combination of two or more. Among these, alkyl (meth)acrylates are preferred. More preferably, methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate; and alkyl (meth)acrylates in which the alkyl group has 6 or more and 12 or fewer carbon atoms. By selecting these monomers, swelling in the electrolyte can be reduced, and cycling characteristics can be improved.

[0068] The proportion of acrylate monomer units in acrylate polymers is typically 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. The upper limit is typically 100% by mass or less, but may also be 98% by mass or less or 95% by mass or less.

[0069] In addition to the monomers represented by general formula (1), the above-mentioned acrylate polymers can also use carboxylic acid-containing monomers that can be copolymerized. Therefore, the acrylate polymers can also contain monomer units having a structure formed by polymerizing carboxylic acid-containing monomers. Specific examples of carboxylic acid-containing monomers include: monocarboxylic acid monomers such as acrylic acid and methacrylic acid; and dicarboxylic acid monomers such as maleic acid, fumaric acid, and itaconic acid. During copolymerization, the amount of carboxylic acid-containing monomer relative to 100 parts by weight of the monomer represented by general formula (1) is generally 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, generally 50 parts by weight or less, preferably 30 parts by weight or less, and more preferably 10 parts by weight or less.

[0070] In addition to the monomers represented by general formula (1), the above-mentioned acrylate polymers can also use nitrile-containing monomers that are capable of copolymerization. Therefore, the acrylate polymers can also contain monomer units having a structure formed by polymerizing nitrile-containing monomers. Specific examples of nitrile-containing monomers include acrylonitrile and methacrylonitrile. The amount of the copolymerizable nitrile-containing monomer relative to 100 parts by weight of the monomer represented by general formula (1) is generally 0.1 parts by weight or more, preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, generally 40 parts by weight or less, preferably 30 parts by weight or less, more preferably 10 parts by weight or less.

[0071] Conjugated diene polymers are homopolymers of conjugated dienes, copolymers obtained by polymerizing mixtures of monomers containing conjugated dienes, or hydrogenated derivatives thereof. Thus, conjugated diene polymers can contain one or more monomer units selected from monomer units having structures formed by polymerizing conjugated dienes and monomer units having structures formed by hydrogenating them (hereinafter, sometimes referred to as "conjugated diene monomer units"). As conjugated dienes, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, substituted and side-chain conjugated hexadienes, etc., are preferred. From the perspective of improving the flexibility and resistance to breakage when forming electrodes, 1,3-butadiene is more preferred. Furthermore, two or more of these conjugated dienes may be included in the monomer mixture.

[0072] When the conjugated diene polymer is a copolymer of the aforementioned conjugated diene and a monomer capable of copolymerizing therewith, examples of such copolymerizable monomers include, for example, α,β-unsaturated nitrile compounds and vinyl compounds having an acid component.

[0073] Specific examples of conjugated diene polymers include: homopolymers of conjugated dienes such as polybutadiene (BR) and polyisoprene (IR); aromatic vinyl-conjugated diene copolymers such as styrene-butadiene copolymer (SBR) and styrene-isoprene copolymer (SIR) that can be modified with carboxyl groups; copolymers of aromatic vinyl-conjugated dienes with carboxylic acid-containing monomers such as styrene-butadiene-methacrylic acid copolymer and styrene-butadiene-itaconic acid copolymer; cyaninated vinyl-conjugated diene copolymers such as acrylonitrile-butadiene copolymer (NBR); block polymers such as styrene-butadiene-styrene copolymer (SBS) and styrene-isoprene-styrene (SIS); and hydrides of conjugated diene polymers such as hydrogenated SBR, hydrogenated NBR, hydrogenated SBS, and hydrogenated SIS.

[0074] The proportion of conjugated diene monomer units in the conjugated diene polymer is preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 80% by mass or less, and more preferably 70% by mass or less. By keeping the proportion of conjugated diene monomer units below the above-mentioned upper limit, good electrolyte resistance can be achieved when manufacturing the electrode. By keeping the proportion of conjugated diene monomer units above the above-mentioned lower limit, sufficient adhesion between the composite particles and the current collector layer can be ensured.

[0075] Fluoropolymers are polymers containing monomer units that include fluorine atoms. Specific examples of fluoropolymers include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, ethylene-trifluorochloroethylene copolymers, and perfluoroethylene-propylene copolymers. PVDF is particularly preferred.

[0076] Furthermore, polymers that can be contained in electrode composite layers, such as those described later, can also be used as adhesive materials.

[0077] The glass transition temperature (Tg1) of the adhesive material contained in the first adhesive layer is, for example, -30°C or higher, preferably -20°C or higher, more preferably -15°C or higher, for example, 25°C or lower, preferably 20°C or lower, more preferably 15°C or lower. This is because by keeping the glass transition temperature (Tg1) within the above range, conductive particles can be well bonded to each other, and the current collector layer can be well bonded to the conductive particles. Furthermore, this improves the strength of the first adhesive layer and suppresses deformation of the conductive adhesive layer during electrode manufacturing and battery use.

[0078] The glass transition temperature of the bonding material can be determined using a differential scanning calorimeter, based on JIS K 7121:1987, at a heating rate of 20 °C / min.

[0079] Furthermore, the glass transition temperature Tg1 of the adhesive material contained in the first adhesive layer is preferably higher than the glass transition temperature Tg2 of the adhesive material contained in the second adhesive layer (described later). This is because by making Tg1 and Tg2 have the aforementioned magnitude relationship, it is easy to obtain a conductive adhesive layer with high layer strength and a high coefficient of friction on one side of the electrode composite material layer.

[0080] The shape of the polymer (adhesive material) that can be included in the first adhesive layer is not particularly limited, but it is preferably granular. This is because even a small amount can exert excellent adhesive force, resulting in good strength of the first adhesive layer. The median particle size of the polymer (adhesive material) particles can be, for example, 0.01 μm or more and 1.0 μm or less. The median particle size of the polymer particles can be determined, for example, by measuring the particle size using a laser diffraction particle size distribution measuring device, and determining the particle size (D50) as the cumulative volume calculated from the smallest particle size side in the obtained particle size distribution (volume basis).

[0081] The proportion of the binder material in the first adhesive layer relative to 100 parts by weight of conductive particles is typically 0.1 parts by weight or more, preferably 1.0 parts by weight or more, more preferably 5.0 parts by weight or more, for example, 60 parts by weight or less, preferably 50 parts by weight or less, and more preferably 45 parts by weight or less. This is because by making the proportion of the binder material in the first adhesive layer at or above the aforementioned lower limit, the conductive particles can be well bonded to each other, and the current collector layer can be well bonded to the conductive particles. Furthermore, by making the proportion of the binder material in the first adhesive layer at or below the aforementioned upper limit, the resistance between the current collector layer and the electrode active material can be effectively reduced.

[0082] The first adhesive layer comprises at least conductive particles and a bonding material, and may further comprise any other components as needed. As any other component, for example, carboxymethyl cellulose and a surfactant can be used. The carboxymethyl cellulose and surfactant described in Japanese Patent Application Publication No. 2010-108971 can be used.

[0083] The first adhesive layer is typically disposed directly on the current collector layer without any other layers in between. Furthermore, the first adhesive layer is typically disposed over the entire surface of the region where the electrode composite layer is disposed.

[0084] The thickness of the first adhesive layer is sufficient to ensure the conductivity of both the current collector layer and the electrode composite layer. The thickness of the first adhesive layer is typically 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.3 μm or more, typically 3.0 μm or less, preferably 2.0 μm or less, and more preferably 1.0 μm or less. This is because by making the thickness of the first adhesive layer at or above the aforementioned lower limit, the resistance between the current collector layer and the electrode active material can be effectively reduced. Furthermore, by making the thickness of the first adhesive layer at or below the aforementioned upper limit, good contact adhesion of the conductive adhesive layer surface can be achieved, resulting in good high-speed molding performance. Additionally, good high-temperature storage performance is also achieved.

[0085] like Figure 1 As shown, the thickness of the first adhesive layer refers to the distance t1 in the thickness direction from the surface of the current collector layer 1 of the adhesive layer 21 to the surface where the second adhesive layer 2 is formed. Sometimes the thickness of the first adhesive layer 21 may differ between the portion where the second adhesive layer 22 is formed and the portion where the second adhesive layer 22 is not formed. In such cases, the thickness of the first adhesive layer 21 can be measured in the portion where the second adhesive layer 22 is not formed. The thickness of the first adhesive layer can be determined, for example, by observing the cross-section of the electrode using a transmission electron microscope.

[0086] The contact adhesion of the surface of the first adhesive layer in the conductive adhesive layer is, for example, 0.01 N or more, preferably 0.02 N or more. Furthermore, the higher the contact adhesion of the surface of the first adhesive layer in the conductive adhesive layer, the more preferred it is, typically around 0.1 N or less.

[0087] The contact adhesion of the surface of the first adhesive layer in the conductive adhesive layer can be measured as follows: A sample with the first adhesive layer disposed on the current collector layer is prepared. A probe with a diameter of 5 mm is pressed onto the surface of the first adhesive layer of the sample at a speed of 1 mm / s, and held for 10 seconds. The maximum load when pulled up at a speed of 1 mm / s is measured. This measurement can be performed using, for example, an adhesion testing machine (RHESCA "TAC-1000"). The first adhesive layer disposed on the current collector layer during the electrode manufacturing process can also be used as the sample.

[0088] [3.2. Second adhesive layer]

[0089] The second adhesive layer is a layer partially disposed on the first adhesive layer and in contact with the electrode composite material layer. The second adhesive layer is any one of the layers having the following configuration (a) or (b).

[0090] (a) A layer comprising conductive particles and a binder material, wherein the proportion of conductive particles is lower than that of the first adhesive layer.

[0091] (b) A layer containing a binding material but not conductive particles.

[0092] When the second adhesive layer has the structure described in (a) above, the second adhesive layer typically contains at least a bonding material and conductive particles, and may contain any components as needed. Furthermore, in this embodiment, when the second adhesive layer contains conductive particles, the proportion of conductive particles in the second adhesive layer is typically lower than the proportion of conductive particles in the first adhesive layer.

[0093] The proportion of conductive particles in the second adhesive layer relative to the solid content of the second adhesive layer is typically greater than 0% by mass, and is 0.1% by mass or more. Furthermore, the proportion of conductive particles in the second adhesive layer relative to the solid content of the second adhesive layer is, for example, 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0094] On the other hand, when the second adhesive layer has the configuration described in (b) above, the second adhesive layer does not contain conductive particles but contains a binding material, and can contain any components as needed. Furthermore, the second adhesive layer typically does not contain conductive materials other than conductive particles.

[0095] In this embodiment, it is more preferable that the second adhesive layer is a layer having the configuration of (b) among the layers having (a) and (b), that is, it is more preferable that the second adhesive layer contains a binder material but does not contain conductive particles. This is because by making the second adhesive layer free of conductive particles, the proportion of binder material on one side surface of the electrode composite layer of the conductive adhesive layer can be increased, the coefficient of friction can be increased, and thus the movement of composite particles during electrode manufacturing can be effectively restricted, allowing the electrode to be formed at a higher speed.

[0096] The conductive particles that can be included in the second adhesive layer can be appropriately selected from the conductive particles described as those that can be included in the first adhesive layer. In this embodiment, the conductive particles included in the first adhesive layer may be referred to as conductive particles 1, and the conductive particles included in the second adhesive layer may be referred to as conductive particles 2. Furthermore, conductive particles 1 and conductive particles 2 may be of the same type or different types.

[0097] The adhesive material that can be included in the second adhesive layer is preferably an adhesive material whose glass transition temperature (Tg2) is within a specified range. Specifically, the glass transition temperature (Tg2) of the adhesive material that can be included in the second adhesive layer is typically -50°C or higher, preferably -45°C or higher, and more preferably -40°C or higher. Furthermore, the aforementioned glass transition temperature (Tg2) is typically -10°C or lower, preferably -15°C or lower, and more preferably -25°C or lower. This is because by keeping the glass transition temperature (Tg2) within the above range, the strength of the second adhesive layer and its adhesion to the composite particles are good. Furthermore, the glass transition temperature (Tg2) of the adhesive material included in the second adhesive layer is preferably lower than the glass transition temperature (Tg1) of the adhesive material included in the first adhesive layer.

[0098] The shape of the adhesive material included in the second adhesive layer is not particularly limited, but it is preferably granular. This is because even a small amount can exert excellent adhesive force, resulting in good strength of the second adhesive layer. Furthermore, by ensuring good strength of the second adhesive layer, the movement of the composite particles can be easily physically restricted, thus effectively limiting particle movement during electrode manufacturing. The median particle size of the adhesive material is typically 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.15 μm or more. It is typically 1.0 μm or less, preferably 0.5 μm or less, more preferably 0.4 μm or less, and even more preferably 0.25 μm or less. The median particle size of the adhesive material included in the second adhesive layer is preferably smaller than the median particle size of the conductive particles included in the first adhesive layer.

[0099] The adhesive material that can be included in the second adhesive layer can be appropriately selected from the polymers described as adhesive materials that can be included in the first adhesive layer. In this embodiment, the adhesive material included in the first adhesive layer may also be referred to as adhesive material 1, and the adhesive material included in the second adhesive layer may be referred to as adhesive material 2. Furthermore, adhesive material 1 and adhesive material 2 may be of the same type or different types.

[0100] As any component that can be included in the second adhesive layer, it can be appropriately selected from the polymers described as any component that can be included in the first adhesive layer. In this embodiment, any component included in the first adhesive layer may also be referred to as arbitrary component 1, and any component included in the second adhesive layer may be referred to as arbitrary component 2. Furthermore, arbitrary component 1 and arbitrary component 2 may be of the same type or different types.

[0101] The second adhesive layer is disposed directly on the first adhesive layer. Unless otherwise specified, "directly" disposed on another layer means that there are no other layers between the two layers. Furthermore, the second adhesive layer is partially disposed on the first adhesive layer. In this embodiment, the second adhesive layer is preferably disposed regularly on a portion of the surface of the first adhesive layer. This is because the second adhesive layer can be easily manufactured using methods such as printing. Furthermore, it is easy to adjust the balance between the areas on the conductive adhesive layer where the second adhesive layer is disposed and the areas where the second adhesive layer is not disposed, thereby manufacturing an electrode in a manner that reduces resistance.

[0102] When a second adhesive layer is regularly disposed on a portion of the surface of the first adhesive layer, viewed in the thickness direction, the second adhesive layer may have a linear shape, for example, and can be configured as stripes where areas with the second adhesive layer and areas without the second adhesive layer are alternately arranged. Alternatively, instead of linear second adhesive layers, rectangular second adhesive layers can be arranged, or the second adhesive layer can be configured as dashed stripes. Furthermore, for example, the second adhesive layer may have at least one shape, such as a circle, an ellipse, or a polygon, and multiple second adhesive layers can be arranged at predetermined intervals. Moreover, the second adhesive layer can be configured regularly, for example, as in the pattern coating shape described in Japanese Patent Application Publication No. 2014-078497.

[0103] Furthermore, the second adhesive layer need only be disposed at least on the first adhesive layer; for example, it is preferably partially disposed on the surface of the current collector layer on the side where the first adhesive layer is disposed. Specifically, as... Figure 2As shown, the second adhesive layer 22 is preferably continuously disposed on the first adhesive layer 21 and the current collector layer 1 such that it covers the end of the first adhesive layer 21. Typically, at the end of the electrode, there is a structural tendency for composite particles to be difficult to retain. Therefore, when an electrode composite layer is disposed on the first adhesive layer containing a large number of conductive particles at the end of the electrode, the first adhesive layer cannot adequately bond the composite particles and cannot retain them, thus potentially leading to peeling of the electrode composite layer. In contrast, by continuously disposing a second adhesive layer with good adhesion on the first adhesive layer and the current collector layer, the adhesion between the composite particles contained in the electrode composite layer and the second adhesive layer can be improved, thus effectively suppressing peeling of the electrode composite layer at the end of the electrode. Furthermore, when using the electrode to manufacture a non-aqueous secondary battery and storing it at high temperatures, degradation starting from the peeled portion of the electrode composite layer at the end of the electrode can be suppressed, thus ensuring good high-temperature storage performance of the battery. When the second adhesive layer is disposed to cover the end of the first adhesive layer, it is disposed to cover at least a portion of the end of the first adhesive layer. In cases where the electrode is elongated, for example, the second adhesive layer is preferably provided in such a way that it covers the two ends of the first adhesive layer in the width direction.

[0104] The extent to which the second adhesive layer partially covers the first adhesive layer can be appropriately selected based on the application of the electrode, etc. The ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer (hereinafter, sometimes referred to as the coverage ratio of the first adhesive layer) is typically 20% or more, preferably 30% or more, and more preferably 40% or more. Furthermore, the coverage ratio of the first adhesive layer is typically 80% or less, preferably 70% or less, and more preferably 50% or less. This is because by making the coverage ratio of the first adhesive layer above or below the aforementioned lower limit, high-speed molding performance can be improved, and by making the coverage ratio of the first adhesive layer within the aforementioned range, the low resistance and high-speed molding performance of the electrode can be effectively utilized.

[0105] The thickness of the second adhesive layer is typically 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.3 μm or more, typically 2.0 μm or less, preferably 1.0 μm or less, and more preferably 0.8 μm or less. This is because by keeping the thickness of the second adhesive layer within the above range, the strength of the second adhesive layer can be improved. Furthermore, because unevenness can be provided on one side of the conductive adhesive layer's second adhesive layer, the movement of the composite particles is easily restricted during electrode manufacturing, resulting in good high-speed molding performance.

[0106] Furthermore, in this embodiment, it is preferable to set the first adhesive layer and the second adhesive layer such that the ratio (t2 / t1) of the thickness t2 of the second adhesive layer to the thickness t1 of the first adhesive layer is within a predetermined range. The ratio (t2 / t1) of the thickness t2 of the second adhesive layer to the thickness t1 of the first adhesive layer is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.5 or more, preferably 10 or less, more preferably 3 or less, and even more preferably 1 or less. This is because when the aforementioned thickness ratio (t2 / t1) is at or above the lower limit, the desired high-speed molding performance can be stably obtained, and when the aforementioned thickness ratio is at or below the upper limit, a significant reduction in resistance can be achieved.

[0107] The thickness of the second adhesive layer refers to the distance t2 in the thickness direction from the surface of the first adhesive layer 21 on one side of the second adhesive layer 22 to the surface on which the electrode composite material layer 3 is formed. The thickness of the second adhesive layer can be determined, for example, by observing the cross-section of the electrode using a transmission microscope.

[0108] The contact adhesion of the surface of the second adhesive layer in the conductive adhesive layer is, for example, greater than 0.1 N, preferably 0.3 N or more, and more preferably 0.4 N or more. Furthermore, a higher contact adhesion of the surface of the second adhesive layer in the conductive adhesive layer is more preferred, for example, around 3.0 N or less.

[0109] The contact tack of the second adhesive layer surface in a conductive adhesive layer is typically higher than that of the first adhesive layer surface. In one example, the ratio of the contact tack of the second adhesive layer surface to the contact tack of the first adhesive layer surface (second adhesive layer / first adhesive layer) is typically greater than 1.0, preferably 30 or more, more preferably 70 or more, further preferably 120 or more, and more preferably 150 or more. The upper limit can be, for example, 300 or less, preferably 220 or less, and more preferably 170 or less.

[0110] The contact adhesion of the surface of the second adhesive layer in the conductive adhesive layer can be measured as follows: A sample having a first adhesive layer disposed on the current collector layer and a second adhesive layer partially disposed on the first adhesive layer is prepared. The surface of the second adhesive layer of the sample is measured using the same method as for the contact adhesion of the first adhesive layer. Alternatively, a sample in which a second adhesive layer is disposed on the first adhesive layer of the current collector layer during the electrode manufacturing process can also be used as a sample.

[0111] [3.3. Contact Adhesion of Conductive Adhesive Layer]

[0112] In this embodiment, the contact adhesion of the conductive adhesive layer surface is typically greater than 0.1 N, preferably 0.3 N or more, and more preferably 0.4 N or more. Furthermore, a higher contact adhesion of the conductive adhesive layer surface is more preferable, for example, around 3.0 N or less. The contact adhesion of the conductive adhesive layer can be measured as follows: a sample having a conductive adhesive layer having a first adhesive layer and a second adhesive layer disposed on a current collector layer is prepared, and the contact adhesion of the second adhesive layer surface of the sample is measured using the same method as that of the first adhesive layer. This is because by keeping the contact adhesion of the conductive adhesive layer surface within the aforementioned range, it is possible to effectively achieve both low resistance and high-speed molding of the electrode for non-aqueous secondary batteries. The contact adhesion of the conductive adhesive layer surface is typically taken to be the same value as that of the second adhesive layer surface.

[0113] [4. Electrode Composite Material Layer]

[0114] The electrode composite material layer is a layer disposed on a conductive adhesive layer and comprising an electrode active material and a binder material. In this embodiment, the electrode composite material layer is typically manufactured using composite particles containing an electrode active material and a binder material, thus the electrode composite material layer can comprise composite particles. Furthermore, if the electrode composite material layer further comprises any of the components described later, it is preferable to manufacture it using composite particles containing any of the components, therefore the electrode composite material layer preferably comprises composite particles containing any of the components.

[0115] The electrode active material can be appropriately selected according to the type of non-aqueous secondary battery. Furthermore, the electrode active material can be either a positive electrode active material or a negative electrode active material. In the case of a lithium-ion secondary battery, examples of positive electrode active materials include metal oxides capable of reversibly doping and dedoping lithium ions. Examples of such metal oxides include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFeO4), and ternary active materials (e.g., LiCoO2) in which a portion of the lithium cobalt oxide is replaced by nickel and manganese. 1 / 3 Ni 1 / 3 Mn 1 / 3O2, LiNi 0.5 Co 0.2 Mn 0.3 O2). The positive electrode active material can be used alone or in combination.

[0116] In the case of non-aqueous secondary batteries, specifically lithium-ion secondary batteries, examples of negative electrode active materials include: low-crystallinity carbon (amorphous carbon) (e.g., easily graphitized carbon, difficult-to-graphitize carbon, pyrolytic carbon); graphite (e.g., natural graphite, artificial graphite); alloy materials containing tin, silicon, etc.; oxides (e.g., silicon oxide, tin oxide, lithium titanate), etc. A single negative electrode active material can be used, or multiple materials can be used in combination.

[0117] The electrode active material is preferably in granular form. If the particles are granular, the electrode active material can be molded to form a high-density electrode.

[0118] The median particle size of the electrode active material is preferably 0.1 μm or more and 100 μm or less, more preferably 0.3 μm or more and 50 μm or less, and even more preferably 0.5 μm or more and 30 μm or less. If the median particle size of the electrode active material is within the above range, it is a preferred material for use as an electrode in a lithium-ion battery. The median particle size of the electrode active material is the median particle size based on volume, and its determination method can be the same as that used for determining the median particle size of the polymer described above.

[0119] The content of electrode active material in the electrode composite material layer is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 95% by mass or more, preferably 99.5% by mass or less, more preferably 99% by mass or less, and even more preferably 98.5% by mass or less. By ensuring the content of electrode active material is at or above the aforementioned lower limit, a high electrochemical element capacity can be obtained. By ensuring the content of electrode active material is at or below the aforementioned upper limit, good high-temperature storage characteristics can be obtained. When the electrode composite material layer contains composite particles, the content of electrode active material in 100% by mass of the composite particles can be within the aforementioned numerical range.

[0120] Polymers are typically used as the binder material that can be included in the electrode composite layer. The polymer used as the binder material can be a non-water-soluble polymer. Preferred examples of binders that can be included in the electrode composite layer include acrylate polymers, conjugated diene polymers, and fluorinated polymers. From the viewpoint of manufacturing electrodes for non-aqueous secondary batteries by pressing composite particles containing electrode active materials and binders into shape using a dry process, conjugated diene polymers are preferred.

[0121] The fluorinated polymers that can be included in the electrode composite layer can be appropriately selected from the polymers described as fluorinated polymers that can be included in the first adhesive layer.

[0122] The conjugated diene polymer that can be included in the electrode composite layer can be appropriately selected from the polymers described as conjugated diene polymers that can be included in the first adhesive layer.

[0123] As described above, acrylate polymers are polymers comprising monomer units having a structure formed by polymerizing monomers [(meth)acrylates] represented by general formula (1). As the monomer represented by general formula (1), monomers can be appropriately selected from those described as monomers of acrylate polymers that can be included in the first adhesive layer. Two or more (meth)acrylates represented by general formula (1) can be used alone or in combination. Among these, alkyl (meth)acrylates are preferred, more preferably: methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate; and alkyl (meth)acrylates having 6 or more and 12 or fewer carbon atoms in the alkyl group. By selecting these, swelling in the electrolyte can be reduced, and cycling characteristics can be improved.

[0124] The proportion of acrylate monomer units in acrylate polymers is typically 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. The upper limit is typically 100% by mass or less, but may also be 98% by mass or less or 95% by mass or less.

[0125] Furthermore, when the acrylate polymer is a copolymer of the monomer represented by the above general formula (1) and a monomer capable of copolymerizing therewith, the monomer capable of copolymerization may include, for example, carboxylic acid esters having two or more carbon-carbon double bonds, aromatic vinyl monomers, amide monomers, olefins, diene monomers, vinyl ketones, and heterocyclic vinyl compounds, as well as α,β-unsaturated nitrile compounds and vinyl compounds having acid components.

[0126] Among the monomers that can be copolymerized, aromatic vinyl monomers are preferred from the perspectives of being less prone to deformation and having high strength during electrode manufacturing, and providing sufficient adhesion between the conductive adhesive layer and the current collector. Examples of aromatic vinyl monomers include styrene.

[0127] When the acrylate polymer contains aromatic vinyl monomers, the proportion of aromatic vinyl monomers in the acrylate polymer is, for example, 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 30% by mass or less. This is because by keeping the proportion of aromatic vinyl monomers within the above-mentioned range, the adhesion between the active material layer and the conductive adhesive layer can be sufficiently improved.

[0128] As an adhesive material, polymers that can be contained in, for example, the adhesive material of the first adhesive layer can also be used.

[0129] In this embodiment, the electrode composite material layer is typically manufactured using composite particles containing the aforementioned electrode active material and binder material, thus the electrode composite material layer can contain composite particles containing the aforementioned electrode active material and binder material.

[0130] The proportion of binder material in the electrode composite material layer is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, preferably 5% by mass or less, more preferably 3.5% by mass or less, and even more preferably 2.5% by mass or less. When the electrode composite material layer contains composite particles, the proportion of binder material in 100% by mass of the composite particles can be within the above-mentioned range.

[0131] The electrode composite material layer comprises at least an electrode active material and a binder material, and may further comprise any other components as needed. Examples of such components include carboxymethyl cellulose, water-soluble polymers containing acidic functional groups, and conductive materials.

[0132] The electrode composite material layer can contain carboxymethyl cellulose as an arbitrary component. From the viewpoint of achieving the effect of a thickener, and from the viewpoint of obtaining good high-temperature storage properties and good cycling properties, the carboxymethyl cellulose has a molecular weight greater than 50,000, preferably 100,000 or more. There is no particular upper limit to the molecular weight, and it can be, for example, 1,000,000 or less. The molecular weight can be a weight-average molecular weight. The molecular weight can be determined by methods such as GPC. The content of carboxymethyl cellulose in the electrode composite material layer is preferably 0.3% by mass or more and 5% by mass or less. When the electrode composite material layer contains composite particles, the content of carboxymethyl cellulose in 100% by mass of the composite particles can be within the above-mentioned range.

[0133] The electrode composite material layer can contain any water-soluble polymer with acidic functional groups as an ingredient. "Water-soluble" means that when 0.5g of the polymer is dissolved in 100g of water at 25°C, the insoluble component is less than 1.0% by mass.

[0134] The water-soluble polymer containing acidic functional groups can be a polymer comprising monomer units formed by polymerizing monomers having acidic functional groups and polymerizable unsaturated bonds. The water-soluble polymer containing acidic functional groups can be a polymer other than carboxymethyl cellulose. Examples of such polymers include polyacrylic acid, polymethacrylic acid, polyitacrylic acid, polymaleic acid, polyfumaric acid, poly-2-hydroxyethyl acrylate (PHEA), poly-2-hydroxyethyl methacrylate (PHEMA), and mixtures thereof. Polyacrylic acid, polymethacrylic acid, polyitacrylic acid, poly-2-hydroxyethyl acrylate, and mixtures thereof are particularly preferred, and polymethacrylic acid is more preferred. By using the above-preferred polymers, good recycling characteristics can be obtained.

[0135] The molecular weight of water-soluble polymers containing acidic functional groups is typically 1500 or more, preferably 2500 or more, more preferably 5000 or more, typically 50000 or less, preferably 30000 or less, and more preferably 20000 or less. The molecular weight is the weight-average molecular weight. The molecular weight can be determined by methods such as GPC.

[0136] The content of the water-soluble polymer containing acidic functional groups in the electrode composite material layer is preferably 0.01% by mass or more and 1.0% by mass or less. When the electrode composite material layer contains composite particles, the content of the water-soluble polymer containing acidic functional groups in 100% by mass of the composite particles can be within the above-mentioned range.

[0137] The electrode composite layer can contain conductive materials as any component. Conductive materials are components used to ensure electrical contact between the active materials of the electrodes. Examples of conductive materials include carbon black (e.g., acetylene black, Ketjen black, furnace black, etc.), single-walled or multi-walled carbon nanotubes (multi-walled carbon nanotubes include cup stack types), carbon nanotubes, vapor-grown carbon fibers, milled carbon fibers obtained by sintering and pulverizing polymer fibers, single-layer or multi-layer graphene, conductive carbon materials such as carbon nonwoven sheets obtained by sintering nonwoven fabrics made of polymer fibers, and fibers or foils of various metals. These can be used alone or in combination of two or more. Conductive materials containing carbon nanotubes (hereinafter, sometimes referred to as "CNTs") are particularly preferred. Generally, CNTs tend to aggregate easily and are difficult to disperse. However, when the electrode composite layer contains a water-soluble polymer with acidic functional groups as an arbitrary component, even conductive materials containing CNTs can be well dispersed.

[0138] When the electrode composite material layer contains composite particles, the composite particles can contain solvent as an arbitrary component. The amount of solvent contained in the composite particles is typically 10% by mass or less, preferably 5% by mass or less, and more preferably 2% by mass or less.

[0139] The median particle size of the composite particles contained in the electrode composite material layer is typically 0.1 μm or more, preferably 10 μm or more, more preferably 40 μm or more, typically 200 μm or less, preferably 150 μm or less, and more preferably 100 μm or less. The median particle size of the composite particles can be appropriately adjusted by selecting the composite particle material and adjusting the granulation conditions. The median particle size of the composite particles can be determined by measuring the particle size using a laser diffraction / scattering particle size distribution measuring device (e.g., manufactured by Nikkiso Co., Ltd., product name "MicrotracMT-3200II"). In the obtained particle size distribution (volume basis), the particle size (D50) that accounts for 50% of the cumulative volume calculated from the smallest particle size side is determined.

[0140] The method for manufacturing the composite particles is not particularly limited and can be manufactured using known methods. It can be manufactured using methods described, for example, those specified in International Publication No. 2019 / 039560 or International Publication No. 2021 / 172208.

[0141] The electrode composite layer is typically disposed directly on the conductive adhesive layer. Alternatively, the electrode composite layer may be disposed over the entire surface of the region where the conductive adhesive layer is located.

[0142] The thickness of the electrode composite layer can be appropriately selected according to the application of the non-aqueous secondary battery.

[0143] The amount of electrode composite material layer per unit area is sometimes referred to as "mass per unit area." There is no limit to the mass per unit area of ​​the electrode composite material layer; in one example, it is typically 1 mg / cm³. 2 The above is preferably 2 mg / cm³. 2 The above is further preferred to be 5 mg / cm³. 2 The above is usually 100 mg / cm³. 2 The preferred value is 50 mg / cm³. 2 The following is more preferably 30 mg / cm³ 2 the following.

[0144] [5. Manufacturing method of electrodes for non-aqueous secondary batteries]

[0145] An electrode for a non-aqueous secondary battery according to one embodiment of the present invention can be manufactured by any method, but is preferably manufactured by a manufacturing method including the following steps (A) and (B). Hereinafter, this manufacturing method will be described as a manufacturing method for the electrode for a non-aqueous secondary battery of the present invention.

[0146] Process (A): A conductive adhesive layer is formed on the current collector layer by performing a process (A1) of forming a first adhesive layer on the current collector layer and a process (A2) of forming a second adhesive layer on the first adhesive layer.

[0147] Process (B): A process of supplying composite particles containing electrode active material and binder to the second adhesive layer of conductive adhesive layer, applying pressure, and setting the electrode composite material layer.

[0148] According to the present invention, by providing a conductive adhesive layer on the current collector layer, the movement of composite particles supplied to the conductive adhesive layer can be restricted, thereby accelerating the molding speed of the electrode composite material layer using pressure to manufacture the electrode.

[0149] [5.1. Process (A): Process of setting a conductive adhesive layer]

[0150] Step (A) includes: a step (A1) of forming a first adhesive layer on the current collector layer; and a step (A2) of partially forming a second adhesive layer on the first adhesive layer. By performing steps (A1) and (A2), a conductive adhesive layer can be formed on the current collector layer.

[0151] The current collector layer used in step (A) is preferably a strip. Here, a strip current collector layer refers to a current collector layer having a length of 5 times or more relative to its width, preferably 10 times or more. Specifically, it refers to a current collector layer with a length sufficient to be wound into a roll for storage or transportation. There is no particular upper limit to the length of the current collector layer; for example, it can be less than 100,000 times its width.

[0152] In step (A1), as a method for setting the first adhesive layer on the current collector layer, an example is the following: preparing a coating liquid containing the material of the first adhesive layer and applying it to the current collector layer, drying the coating film, thereby forming the first adhesive layer. Regarding the solvent that can be used in the coating liquid, an example is ion-exchanged water.

[0153] There are no particular limitations on the application method of the coating liquid; any known method can be used. Specifically, methods such as doctor blade application, dip application, reverse roller application, direct roller application, gravure printing, extrusion application, and brush application can be used. The thickness of the coating film can be appropriately set based on the thickness of the first adhesive layer obtained after drying.

[0154] The drying method for the first adhesive layer coating can be any known drying method, such as drying using warm air, hot air, or low-humidity air; vacuum drying; or drying using (far)infrared rays, electron beams, etc. The drying temperature is, for example, in the range of 50°C or higher and 300°C or lower. The drying time is, for example, 2 hours or less.

[0155] In step (A2), a method for partially depositing the second adhesive layer on the first adhesive layer can be, for example, as follows: A coating liquid containing the material of the second adhesive layer is prepared and partially applied to the first adhesive layer; the coating is then dried to form the second adhesive layer. The method for applying the coating liquid to the second adhesive layer can be any method that allows the second adhesive layer to be partially deposited on the first adhesive layer; for example, inkjet printing, gravure printing, or screen printing can be used. The thickness of the coating can be appropriately set based on the thickness of the dried second adhesive layer. The drying method, drying temperature, and drying time for the coating of the second adhesive layer can be the same as those described for the coating of the first adhesive layer.

[0156] In process (A2), for example, as Figure 3 As shown, a second adhesive layer in a linear shape can be disposed on the first adhesive layer 21. This second adhesive layer, in a linear shape, is arranged in a striped pattern along an inclined direction relative to the conveying direction MD (the length direction of the current collector layer 1) of the current collector layer 1. This is because by setting the second adhesive layer in a striped pattern in an inclined direction relative to the conveying direction of the current collector layer, the movement of the composite particles supplied in step (B) can be easily restricted. Figure 3 The example shown is a second adhesive layer with multiple line shapes. Although not illustrated, it is also possible to arrange rectangular second adhesive layers or to set the second adhesive layer as a stripe shape with dashed lines.

[0157] The tilt direction relative to the conveying direction of the current collector layer usually refers to a direction perpendicular to the thickness direction, which is neither the length direction nor the width direction of the current collector layer.

[0158] The second adhesive layer is provided in such a way that it at least partially covers the first adhesive layer. For example, as Figure 3 As shown, when the current collector layer 1 is a long strip, it is preferable that the width S1 of the region where the first adhesive layer 21 is provided on the current collector layer 1 and the width S2 of the region where the second adhesive layer 22 is provided satisfy the relationship expressed by the following formula (1). This is because it can improve the strength of the end in the width direction of the conductive adhesive layer, and can make the adhesion between the current collector layer and the conductive adhesive layer, as well as the adhesion between the conductive adhesive layer and the electrode composite material layer, good.

[0159]

[0160] Formula (1) will be explained in further detail. "S2 / S1×100" is preferably 100 or more, more preferably 100.5 or more, preferably 110 or less, more preferably 105 or less, and even more preferably 103 or less. When "S2 / S1×100" is within such a range, the high-temperature storage performance of the secondary battery can be significantly improved.

[0161] like Figure 3 As shown, the width S1 of the region where the first adhesive layer 21 is provided refers to the distance in the width direction of the region where the first adhesive layer 21 is provided in the current collector layer 1. Furthermore, the width S2 of the region where the second adhesive layer 22 is provided refers to the distance between the outer ends of the two second adhesive layers located at the outermost end in the width direction of the current collector layer 1.

[0162] When the width S1 of the region where the first adhesive layer is disposed on the current collector layer and the width S2 of the region where the second adhesive layer is disposed satisfy the relationship expressed by the above formula (1), the first adhesive layer and the second adhesive layer are disposed in such a way that the region where the second adhesive layer is disposed generally overlaps the region where the first adhesive layer is disposed entirely.

[0163] [5.2. Process (B): Process of setting the electrode composite material layer]

[0164] Step (B) is a process of supplying composite particles containing electrode active material and binder material to the second adhesive layer of the conductive adhesive layer obtained in step (A), applying pressure, and setting the electrode composite material layer.

[0165] There are no restrictions on the form of the binder material that can be included in the composite particles supplied to the second adhesive layer. Therefore, when using a polymer as the binder material, the polymer can be a particulate polymer or a non-particulate polymer. The particulate polymer refers to the polymer particles described above as binders that can be included in the electrode composite layer. Furthermore, the non-particulate polymer is a polymer having a non-particulate form, and can have, for example, an indeterminate shape. This non-particulate polymer can be, for example, a solvent-type polymer that can dissolve in the solvent used in manufacturing the composite particles, or it can be an indeterminate polymer formed by drying the solvent during the manufacturing process of the composite particles. In one example, a non-particulate polymer can be used as the binder material for the positive electrode, and a particulate polymer can be used as the binder material for the negative electrode. The median particle size in terms of volume of the particulate polymer is, for example, 40 nm or more, preferably 50 nm or more, more preferably 70 nm or more, for example, 500 nm or less, preferably 400 nm or less, more preferably 300 nm or less.

[0166] As a method for supplying composite particles to the second adhesive layer of the conductive adhesive layer, one example is the following method: a current collector layer provided with the conductive adhesive layer is conveyed by a roller, and composite particles are supplied to the conveyed current collector layer using a known supply device.

[0167] As a method for setting an electrode composite material layer by pressurizing composite particles, a common example is the use of a roll forming apparatus with a pair of rollers. In this invention, the movement of the composite particles supplied to the conductive adhesive layer can be restricted and roll forming can be performed, thus accelerating the forming speed.

[0168] The temperature during roll forming is preferably 0°C or higher and 200°C or lower, more preferably 25°C or higher and 150°C or lower. The linear pressure between the rolls during roll forming is preferably 0.2 kN / cm or higher, more preferably 1.5 kN / cm or higher, preferably 30 kN / cm or lower, and more preferably 15 kN / cm or lower. By controlling the linear pressure within the above range, the uniformity of the electrode composite material layer thickness can be improved.

[0169] The forming speed during roll forming is preferably 10 m / min or more, more preferably 30 m / min or more, more preferably 70 m / min or less, and more preferably 50 m / min or less.

[0170] Furthermore, to eliminate deviations in electrode thickness after molding and increase the density of the electrode active material layer to achieve high capacity, further pressurization can be applied after molding. This pressurization is typically performed using a roller pressing process. In this roller pressing process, two cylindrical rollers are usually arranged parallel to each other with a narrow gap, rotating in opposite directions to grip the electrode between them, thereby applying pressure. The rollers can also be heated or cooled as needed for temperature adjustment.

[0171] [6. Variations]

[0172] In this invention, electrodes that reduce resistance and have good high-speed formability can also be provided, for example, the following electrodes.

[0173] An electrode for a non-aqueous secondary battery comprises, in sequence, a current collector layer, a conductive adhesive layer, and an electrode composite material layer, wherein the contact adhesion of one side surface of the electrode composite material layer of the conductive adhesive layer is greater than 0.1N.

[0174] According to the modified example, the conductive adhesive layer is conductive, and the contact adhesion on one side of the electrode composite material layer is high, thus reducing the resistance. Furthermore, the movement of the composite particles is restricted and pressure molding is performed during electrode manufacturing, thus enabling the production of electrodes with high high-speed formability.

[0175] The contact adhesion of the conductive adhesive layer is typically greater than 0.1 N, preferably 0.3 N or more, and more preferably 0.4 N or more. Furthermore, a higher contact adhesion of the surface of the second adhesive layer in the conductive adhesive layer is preferred, for example, around 3.0 N or less. The contact adhesion of the conductive adhesive layer can be measured by preparing a sample with a conductive adhesive layer disposed on the current collector layer, and measuring the contact adhesion of the conductive adhesive layer surface of the sample using the same method as for the first adhesive layer.

[0176] The conductive adhesive layer is preferably a layer in which one side of the electrode composite material layer exhibits the aforementioned contact adhesion and conductivity along the thickness direction of the layer. Examples of such conductive adhesive layers include, for instance, layers comprising conductive particles and a binder material. Furthermore, the aforementioned conductive adhesive layer with a bilayer structure having a first adhesive layer and a second adhesive layer can also be considered as a conductive adhesive layer in a modified example.

[0177] Regarding the modified example, it includes a conductive adhesive layer having the above-described contact adhesion, except that it can be the same as the content described in the electrode of one embodiment described above.

[0178] [7. Non-aqueous secondary batteries]

[0179] The non-aqueous secondary battery of the present invention has a positive electrode, a negative electrode and an electrolyte, wherein at least one of the positive electrode and the negative electrode is an electrode for the non-aqueous secondary battery.

[0180] The non-aqueous secondary battery of the present invention, by having the aforementioned electrodes for non-aqueous secondary batteries, enables the manufacture of a non-aqueous secondary battery with reduced electrode resistance. Furthermore, electrodes with excellent high-speed prototyping capabilities can be used to manufacture the non-aqueous secondary battery, thus enabling the production of high-yield non-aqueous secondary batteries. Moreover, by having the electrodes of the present invention, a secondary battery with good high-temperature storage properties can be manufactured.

[0181] In the case of non-aqueous secondary batteries, specifically lithium-ion secondary batteries, an electrolyte prepared by dissolving the electrolyte in a solvent can be used as the electrolyte.

[0182] Here, an organic solvent capable of dissolving electrolytes can be used as the solvent. Specifically, a solvent prepared by adding viscosity-adjusting solvents such as 2,5-dimethyltetrahydrofuran, tetrahydrofuran, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, methyl acetate, dimethoxyethane, dioxane, methyl propionate, and methyl formate to an alkyl carbonate-based solvent such as ethylene carbonate, propylene carbonate, and γ-butyrolactone can be used.

[0183] Lithium salts can be used as electrolytes. Among these lithium salts, those described in, for example, Japanese Patent Application Publication No. 2012-204303 can be used. From the perspective of their ease of dissolution in organic solvents and their high degree of dissociation, LiPF6, LiClO4, and CF3SO3Li are preferred as electrolytes.

[0184] Furthermore, non-aqueous secondary batteries may further include spacers as needed. As spacers, for example, those described in Japanese Patent Application Publication No. 2012-204303 can be used. Among these, a microporous membrane made of a polyolefin-based resin (polyethylene, polypropylene, polybutene, polyvinyl chloride) is preferred from the perspective of reducing the overall film thickness of the spacer, thereby increasing the ratio of electrode active materials within the lithium-ion secondary battery and thus increasing the capacity per unit volume.

[0185] As a method for manufacturing non-aqueous secondary batteries, they can be manufactured in the following ways: positive and negative electrodes are overlapped with a spacer between them; the batteries are then wound, folded, or otherwise arranged according to their shape as needed, placed in a battery container, electrolyte is injected into the container, and the container is sealed. To prevent internal pressure build-up and overcharging / discharging, overcurrent protection components such as fuses and PTC elements, porous metal mesh, and conductive plates can be added as needed. The shape of the secondary battery can be any of the following: coin-shaped, button-shaped, sheet-shaped, cylindrical, square, or flat.

[0186] Example

[0187] The present invention will now be specifically described with reference to the embodiments shown below. However, the present invention is not limited to the embodiments shown below, and can be implemented in any way without departing from the scope of the claims and their equivalents.

[0188] In the following descriptions, unless otherwise specified, the percentage (%) indicates quantity by mass. Furthermore, unless otherwise specified, the parts (%) indicate quantity by weight. Additionally, unless otherwise specified, the operations described below are performed under normal temperature and pressure conditions.

[0189] [Evaluation Method]

[0190] <Adhesive strength (contact adhesion)>

[0191] In the embodiments and comparative examples, the contact adhesion of the surface of the adhesive layer disposed on the current collector layer was measured. Specifically, in the embodiments, the contact adhesion of the surface of the first adhesive layer disposed on the current collector layer and the contact adhesion of the surface of the second adhesive layer in a conductive adhesive layer having the first adhesive layer disposed on the current collector layer and having a second adhesive layer disposed on the first adhesive layer were measured. The contact adhesion of the surface of the second adhesive layer in the embodiments can also be evaluated as the contact adhesion of the surface of the conductive adhesive layer in the double-layer structure. On the other hand, in the comparative examples, the contact adhesion of the surface of the first adhesive layer or the second adhesive layer disposed on the current collector layer was measured. The contact adhesion was measured using a "TAC-1000" manufactured by RHESCA Corporation. Specifically, a probe (SUS manufactured) with a diameter of 5 mm was pressed onto the conductive adhesive layer at a speed of 1 mm / s and a load of 4000 gf, and then held for 10 seconds. The maximum load when pulled up at a speed of 1 mm / s was measured. The higher the value, the better the adhesive strength.

[0192] <High-speed prototyping>

[0193] In the embodiments and comparative examples, composite particles (granulated particles) are supplied to a conductive adhesive layer disposed on a current collector layer, and the electrode is fabricated by accelerating the conveying speed using a roller press described later. The resulting electrode is subjected to an appearance inspection, and the highest forming speed at which no streaks or defects are produced is evaluated based on the following criteria.

[0194] A: 50m / minute or higher

[0195] B: 30m / minute or higher but less than 50m / minute

[0196] C: 10m / min or higher but less than 30m / min

[0197] D: Less than 10m / minute

[0198] <IV Characteristics>

[0199] The lithium-ion secondary batteries in the examples and comparative examples were injected with electrolyte and then left to stand at 25°C for 5 hours. Next, the battery cell voltage was charged to 3.65V using a constant current method at 0.2C and 25°C, followed by an aging treatment at 60°C for 12 hours. Then, the battery cell voltage was discharged to 3.00V using a constant current method at 0.2C and 25°C. Next, a CC-CV charge (upper limit battery cell voltage 4.35V) was performed using a constant current method at 0.2C, followed by a CC discharge to 3.00V using a constant current method at 0.2C. This 0.2C charge-discharge cycle was repeated three times. Then, a charging operation was performed at 0.2C at 25°C to reach 50% SOC, and the voltage V0 was measured after standing at 25°C for 3 hours. Then, a discharge operation was performed at a discharge rate of 1C, and the voltage V1 was measured 10 seconds after the start of discharge. The voltage was calculated using the low-temperature IV resistance (mΩ) = (V0 - V1) / 40 × 1000, and evaluated against the following criteria. A smaller value indicates a better low-temperature IV resistance.

[0200] A: Below 40mΩ

[0201] B: Greater than 40mΩ and less than 42mΩ

[0202] C: Greater than 42mΩ and less than 44mΩ

[0203] D: Greater than 44mΩ and less than 46mΩ

[0204] E: Greater than 46mΩ

[0205] <High-Temperature Storage Characteristics>

[0206] For the lithium-ion secondary batteries in the examples and comparative examples, the initial discharge capacity C0 was measured after charging to a cell voltage of 4.2V using a 0.5C constant current method at 25°C and then discharging to 3.0V. Next, the lithium-ion secondary batteries were charged to a cell voltage of 4.2V using a 0.5C constant current method at 25°C. Then, the lithium-ion secondary batteries were stored at 60°C for three weeks (high-temperature storage). After high-temperature storage, the batteries were discharged to 3V using a 0.5C constant current method at 25°C, and the remaining capacity C1 after high-temperature storage was measured.

[0207] Then, the capacity retention rate (%) is calculated as (remaining capacity C1 / initial discharge capacity C0) × 100, and evaluated using the following benchmarks. A higher capacity retention rate indicates better high-temperature storage characteristics of the lithium-ion secondary battery.

[0208] A: Capacity retention rate is above 90%.

[0209] B: Capacity retention rate is above 85% and below 90%.

[0210] C: Capacity retention rate is above 80% and below 85%.

[0211] D: Capacity retention rate is above 75% and less than 80%.

[0212] E: Capacity retention rate less than 75%

[0213] <Thickness of the first adhesive layer and the second adhesive layer>

[0214] The thicknesses of the first and second adhesive layers were determined as follows: using a slicer, cutting with a glass cutter, and observing the cross-section with a transmission electron microscope.

[0215] <Median particle size of polymer>

[0216] The median particle size of the polymer was determined by laser diffraction. Specifically, the median particle size of the polymer was defined as follows: using an aqueous dispersion of the prepared particulate polymer (solid component concentration 0.1 wt%) as a sample, the cumulative volume calculated from the smallest particle size side in the particle size distribution (volume basis) obtained by laser diffraction particle size distribution measuring device (Beckman Coulter, product name "LS-13320") was taken as 50% of the particle size.

[0217] [Manufacturing Example 1: Method for manufacturing adhesive material I (hydride of SIS) for electrode composite layer]

[0218] 270 parts of dehydrated cyclohexane and 0.53 parts of ethylene glycol dibutyl ether were added to a reactor equipped with a stirrer and thoroughly nitrogen-purified. 0.47 parts of n-butyllithium (15% cyclohexane solution) were then added. While stirring the entire mixture at 60°C, 12.5 parts of dehydrated styrene were continuously added to the reactor over 40 minutes. After the addition was complete, the mixture was stirred at 60°C for another 20 minutes. Gas chromatography analysis showed a polymerization conversion rate of 99.5%. Next, 75.0 parts of dehydrated isoprene were continuously added to the reaction mixture over 100 minutes, followed by stirring for another 20 minutes. The polymerization conversion rate remained at 99.5%. Then, 12.5 parts of dehydrated styrene were continuously added over 60 minutes, followed by stirring for another 30 minutes. The polymerization conversion rate was approximately 100%. Finally, 0.5 parts of isopropanol were added to the reaction mixture to terminate the reaction, yielding a block copolymer [C1]. Of the monomer units derived from isoprene in the obtained block copolymer [C1], 58% were monomer units derived from 1,2- and 3,4-addition polymerization. Next, the polymer solution was transferred to a pressure reactor equipped with a stirrer, and 7.0 parts of a diatomaceous earth-supported nickel catalyst (manufactured by Nichiki Chemical Co., Ltd., product name "E22U", nickel loading 60%) and 80 parts of dehydrated cyclohexane were added and mixed. The reactor interior was purged with hydrogen, and hydrogen was supplied while the solution was further stirred, and the hydrogenation reaction was carried out for 6 hours at a temperature of 190°C and a pressure of 4.5 MPa. After the hydrogenation reaction is complete, the reaction solution is filtered to remove the hydrogenation catalyst. Then, 1.0 part of xylene solution is added to the filtrate and dissolved. The xylene solution contains 0.1 part of pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by KO-YO Chemical Research Institute Co., Ltd., product name "Songnox1010"), which is a phenolic antioxidant. Cyclohexane is further added to obtain a cyclohexane solution of polymer I at a specified concentration.

[0219] [Manufacturing Example 2: Method for Manufacturing Adhesive Material II (SBR1) for Electrode Composite Layers]

[0220] 64 parts styrene, 32 parts 1,3-butadiene, 3 parts itaconic acid, 1 part 2-hydroxyethyl acrylate (β-hydroxyethyl acrylate), 0.3 parts tert-dodecyl mercaptan as a molecular weight regulator, 5 parts sodium dodecylbenzenesulfonate as an emulsifier, 150 parts deionized water as a solvent, and 1 part potassium persulfate as a polymerization initiator were added to a 5 MPa pressure vessel equipped with a stirrer. After thorough stirring, the temperature was raised to 55°C to initiate polymerization. The reaction was terminated by cooling when the monomer consumption reached 95.0%. A 5% sodium hydroxide aqueous solution was added to the resulting aqueous dispersion containing the polymer to adjust the pH to 8. Unreacted monomers were then removed by heated vacuum distillation. The temperature was then cooled to below 30°C to obtain an aqueous dispersion containing particulate polymer II (glass transition temperature Tg: 15°C).

[0221] [Manufacturing Example 3: Method for Manufacturing the Adhesive Material (ACR1) for the First Adhesive Layer]

[0222] 90 parts of ion-exchanged water and 0.23 parts of ammonium persulfate were supplied to a reactor equipped with a stirrer, the gas phase was purged with nitrogen, and the temperature was raised to 70°C. Meanwhile, in another container, 50 parts of ion-exchanged water, 1.0 part of sodium dodecylbenzenesulfonate (manufactured by Kao Chemical Co., Ltd., "Neoplex G-15") as an emulsifier, 31.1 parts of styrene, 63.0 parts of 2-ethylhexyl acrylate, 1.7 parts of allyl glycidyl ether, 0.2 parts of allyl methacrylate, and 4.0 parts of acrylic acid were mixed to obtain a monomer composition. This monomer composition was continuously added to the reactor over 4 hours for polymerization. The reaction was carried out at 80°C during the addition. After the addition was completed, the reaction was further terminated by stirring at 80°C for 3 hours. Then, a 5% sodium hydroxide aqueous solution was added to adjust the pH to 8, thereby obtaining an aqueous dispersion containing a first adhesive layer binder (glass transition temperature Tg: -15°C).

[0223] [Manufacturing Example 4: Method for manufacturing adhesive material I (ACR2) for the second adhesive layer]

[0224] 90 parts of ion-exchanged water and 0.23 parts of ammonium persulfate were supplied to a reactor equipped with a stirrer, the gas phase was purged with nitrogen, and the temperature was raised to 70°C. Meanwhile, in another container, 50 parts of ion-exchanged water, 1.0 part of sodium dodecylbenzenesulfonate (manufactured by Kao Chemical Co., Ltd., "Neoplex G-15") as an emulsifier, 20.1 parts of styrene, 75 parts of 2-ethylhexyl acrylate, 1.7 parts of allyl glycidyl ether, 0.2 parts of allyl methacrylate, and 3.0 parts of acrylic acid were mixed to obtain a monomer composition. This monomer composition was continuously added to the reactor over 4 hours for polymerization. The reaction was carried out at 80°C during the addition. After the addition was completed, the reaction was further terminated by stirring at 80°C for 3 hours. Then, a 5% sodium hydroxide aqueous solution was added to adjust the pH to 8, thereby obtaining an aqueous dispersion containing a second adhesive layer binder I (glass transition temperature Tg: -40°C).

[0225] [Manufacturing Example 5: Method for Manufacturing Adhesive Material II (SBR2) for the Second Adhesive Layer]

[0226] 38 parts styrene, 58 parts 1,3-butadiene, 3 parts itaconic acid, 1 part 2-hydroxyethyl acrylate (β-hydroxyethyl acrylate), 0.3 parts tert-dodecyl mercaptan as a molecular weight regulator, 5 parts sodium dodecylbenzenesulfonate as an emulsifier, 150 parts deionized water as a solvent, and 1 part potassium persulfate as a polymerization initiator were added to a 5 MPa pressure vessel equipped with a stirrer. After thorough stirring, the temperature was raised to 55°C to initiate polymerization. The reaction was terminated by cooling when the monomer consumption reached 95.0%. A 5% sodium hydroxide aqueous solution was added to the resulting aqueous dispersion containing the polymer to adjust the pH to 8. Unreacted monomers were then removed by heated vacuum distillation. The temperature was then cooled to below 30°C to obtain an aqueous dispersion containing adhesive material II for the second adhesive layer (glass transition temperature Tg: -30°C).

[0227] [Example 1]

[0228] (1-1. Construction of the first adhesive layer)

[0229] Add 5.0 parts of carboxymethyl cellulose (manufactured by Daicel Miraizu Co., Ltd., "1220") and 2.5 parts of sodium salt of naphthalenesulfonic acid formaldehyde condensate (manufactured by Kao Chemical Co., Ltd., "Demol N") to 300 parts of ion-exchanged water, and stir at 1500 rpm for 15 minutes using a disperser. Then, add 52.5 parts of graphite (manufactured by Nippon Graphite Co., Ltd., "JB-5") and 13.0 parts of carbon black (manufactured by Denka Co., Ltd., "Li400"), and stir at 2000 rpm for 30 minutes using a disperser. Further add 27 parts of first adhesive layer bonding material I based on solid content equivalents, and stir at 1500 rpm for 15 minutes to obtain the coating solution for the first adhesive layer.

[0230] The first adhesive layer was coated onto an aluminum current collector with a thickness of 15 μm and a width of 30 cm using a kiss-reverse gravure printing method at a coating speed of 10 m / min and a drying temperature of 120 °C. The resulting first adhesive layer had a film thickness of 1.0 μm, a coating width of 25 cm in the width direction, and an adhesive strength of 0.02 N.

[0231] (1-2. Fabrication of the second adhesive layer)

[0232] The above-mentioned adhesive material I for the second adhesive layer is mixed in such a way that the solid content is 30% and the nonionic surfactant DISPANOL TOC (manufactured by Nippon Oil Co., Ltd.) is 0.5%, thereby obtaining the coating liquid for the second adhesive layer.

[0233] The obtained second adhesive layer coating liquid was applied to the current collector layer on which the first adhesive layer was formed using a direct gravure printing method at a coating speed of 40 m / min and a drying temperature of 50°C. At this time, the second adhesive layer coating liquid was applied to the center of the first adhesive layer in a striped pattern. Furthermore, at the ends of the first adhesive layer in the width direction, the second adhesive layer coating liquid was applied to both the first adhesive layer and the current collector layer so that the ends of the first adhesive layer were covered by strips of the second adhesive layer. The resulting second adhesive layer had a film thickness of 0.3 μm, a coating width of 25.5 cm in the width direction, and an adhesive strength of 1.8 N. The ratio (%) of the width S2 of the area coated with the second adhesive layer coating liquid to the width S1 of the area coated with the first adhesive layer coating liquid was set to 102%. Furthermore, the ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer was set to 40%.

[0234] (1-3. Fabrication of composite particles for positive electrode)

[0235] A composite particle production apparatus is prepared, comprising a granulation tank with the following structure: a cylindrical container with an inner diameter of 180 mm and a capacity of 2 L, with the axis of the cylindrical container as the vertical direction, and stirring blades on two axes in the vertical and horizontal directions (the vertical direction being the main stirring blade and the horizontal direction being the auxiliary stirring blade). Furthermore, the main stirring blades have inclined paddle blades, each with three main blades of 170 mm diameter, and the auxiliary stirring blades have V-shaped anchor blades of 30 mm diameter. To prevent raw materials from mixing into the driving parts of the main and auxiliary stirring blades, the granulation tank has a structure for sealing by introducing air. The composite particle production apparatus is used to sequentially perform (i) pre-stirring operation, (ii) composite particle pre-forming operation, and (iii) granulation operation to produce composite particles.

[0236] First, in (i) the pre-stirring operation, 96 parts (1344 g) of NMC532 (LiNi), a Co-Ni-Mn lithium composite oxide active material used as a positive electrode active material for lithium-ion batteries, were added to the granulation tank. 0.5 Co 0.2 Mn 0.3 O2 (average particle size 6μm), 2 parts (28g) of carbon black as a conductive material (BET specific surface area: 62m²) 2 / g, bulk density 0.16g / cm³ 3 Next, room temperature air (hereinafter referred to as "sealing air") was circulated at a rate of 20 L / min (air flow rate 10 L / min) to each drive section of the sealing main and auxiliary stirring blades, and the mixture was stirred for 15 minutes under operating conditions of a circumferential speed of 5 m / s for the main stirring blades and a circumferential speed of 6 m / s for the auxiliary stirring section. The solid content concentration of the powder material after stirring was measured, and the result was above 99%.

[0237] Next, as part of (ii) the pre-forming operation of composite particles, room temperature sealed air was circulated at 20 L / min (air flow rate 10 / min), and under the operating conditions of a main stirring blade with a circumferential speed of 5 m / s and a secondary stirring blade with a circumferential speed of 6 m / s, a cyclohexane solution of polymer I (solid content concentration: 10% by mass, viscosity index: 200 mPa·s) as the binder material I for the electrode composite layer was continuously added through a dropping funnel for 15 minutes.

[0238] Next, as part of (iii) the granulation operation, room temperature sealed air was circulated at 20 L / min (air flow rate 10 / min), and the operation was carried out for 10 minutes under the operating conditions of a circumferential speed of 2 m / s for the main stirring blade and 2 m / s for the auxiliary stirring blade.

[0239] The above operations (i) to (iii) are performed sequentially to obtain composite particles for the positive electrode.

[0240] (1-4. Production of the positive electrode)

[0241] The composite particles for the positive electrode obtained in (1-3) are fed into the pressing rollers of a roller press ("Pressure Cutting Rough Surface Hot Roller" manufactured by Hirano Gikenkogyo Co., Ltd.) using a metering feeder (Nikka Spray KV). The rollers are heated at 50°C and the pressing linear pressure is 1000 kN / m. Aluminum foil with the first and second adhesive layers described above is inserted between the pressing rollers, allowing the composite particles supplied from the metering feeder to adhere. The mixture is then pressed at a forming speed of 5.0 m / min to obtain a product with a unit area mass of 20 mg / cm³. 2 The positive electrode raw material for the positive electrode active material layer was then used. Next, one side of the positive electrode composite material layer of the prepared positive electrode raw material was rolled at a temperature of 25±3℃ to obtain a positive electrode composite material layer with a density of 3.50 g / cm³. 3 The positive pole.

[0242] (1-5. Making the negative electrode)

[0243] 97.4 parts of natural graphite (median particle size on a volume basis: 22 μm, theoretical capacity: 360 mAh / g) as the negative electrode active material and 1.0 part (solids equivalent) of ammonium salt of carboxymethyl cellulose (Daicel Fine Chemicals Co., Ltd., product number "DN-800H") were added to a planetary mixer. The solids concentration of the contents of the mixer was further diluted to 60% with deionized water, and then the mixture was kneaded at a rotation speed of 45 rpm for 60 minutes. Then, 1.5 parts (solids equivalent) of particulate polymer II as a binder II for the electrode composite layer were added, and the contents of the mixer were kneaded at a rotation speed of 40 rpm for 40 minutes. Then, deionized water was added to achieve a viscosity (using a type B viscometer, temperature: 25°C, rotor speed: 60 rpm) of 3000 ± 200 mPa·s, thereby preparing a slurry composition for the negative electrode.

[0244] A notched roller coater was used to apply a coating at a rate of 10.5 ± 0.5 mg / cm³. 2 The obtained negative electrode slurry composition was applied to a 10 μm thick copper foil serving as a current collector. The copper foil was then conveyed at a speed of 0.2 m / min in an oven at 120°C for 2 minutes, and then further conveyed in an oven at 130°C for 2 minutes to dry the slurry composition, thus obtaining a negative electrode raw material with a negative electrode composite layer formed on the current collector.

[0245] Then, one side of the negative electrode composite material layer of the prepared negative electrode raw material was rolled at a temperature of 25±3℃ to obtain a negative electrode composite material layer with a density of 1.60 g / cm³. 3 The negative electrode.

[0246] (1-6. Preparation of spacers)

[0247] As a spacer made of spacer substrate, a single-layer polypropylene spacer (manufactured by Celgard, product name "Celgard 2500") is prepared.

[0248] (1-7. Fabrication of Lithium-ion Secondary Batteries)

[0249] Using the positive electrode obtained in (1-4), the negative electrode obtained in (1-5), and the spacer prepared in (1-6), a cascaded battery cell (equivalent to an initial design discharge capacity of 40 mAh) was fabricated and placed inside an aluminum packaging material. It was then vacuum-dried at 60°C for 10 hours. Next, as the electrolyte, a 1.0 M LiPF6 solution (a mixed solvent of ethylene carbonate (EC) / diethyl carbonate (DEC) = 3 / 7 (volume ratio), containing the additive ethylene carbonate 2% (volume ratio)) was filled. Furthermore, to seal the opening of the aluminum packaging material, it was heat-sealed at 150°C to manufacture a lithium-ion secondary battery. The IV characteristics and high-temperature storage characteristics of this lithium-ion secondary battery were evaluated as described above.

[0250] [Example 2]

[0251] The thickness of the first adhesive layer of the positive electrode was set to 2 μm. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 1 and evaluated.

[0252] [Example 3]

[0253] The thickness of the first adhesive layer of the positive electrode was set to 0.25 μm. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 1 and evaluated.

[0254] [Example 4]

[0255] The thickness of the second adhesive layer of the positive electrode was set to 1 μm. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 1 and evaluated.

[0256] [Example 5]

[0257] The thickness of the second adhesive layer was set to 0.1 μm. Otherwise, the lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0258] [Example 6]

[0259] The thickness of the second adhesive layer was set to 3 μm. Otherwise, the lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0260] [Example 7]

[0261] The amount of sodium dodecylbenzenesulfonate, used as an emulsifier, was changed to 0.5 parts. Otherwise, an aqueous dispersion of a second adhesive layer binder material (glass transition temperature Tg: -40°C) with a median particle size of 0.3 μm (by volume) was obtained using the same method as in Manufacturing Example 4. Using this aqueous dispersion of the second adhesive layer binder material instead of the second adhesive layer binder material I obtained in Manufacturing Example 4, a lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0262] [Example 8]

[0263] The amount of sodium dodecylbenzenesulfonate, used as an emulsifier, was changed to 1.5 parts. Otherwise, an aqueous dispersion of a second adhesive layer binder material (glass transition temperature Tg: -40°C) with a median particle size of 0.08 μm on a volume basis was obtained using the same method as in Manufacturing Example 4. Using this aqueous dispersion of the second adhesive layer binder material instead of the second adhesive layer binder material I obtained in Manufacturing Example 4, a lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0264] [Example 9]

[0265] The ratio (%) of the width S2 of the area coated with the second adhesive layer coating liquid to the width S1 of the area coated with the first adhesive layer coating liquid was set to 105%. Otherwise, a lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1. In this Example 9, the ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer was 40%.

[0266] [Example 10]

[0267] The ratio (%) of the width S2 of the area coated with the second adhesive layer coating liquid to the width S1 of the area coated with the first adhesive layer coating liquid was set to 100%. Otherwise, a lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1. In this Example 10, the ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer was 40%.

[0268] [Example 11]

[0269] The positive and negative electrodes were modified as described below, except that a lithium-ion secondary battery was manufactured using the same procedures as in Example 1. The IV characteristics and high-temperature storage characteristics were evaluated using this lithium-ion secondary battery in the manner described above.

[0270] (2-1. First adhesive layer)

[0271] Add 5.0 parts of carboxymethyl cellulose (manufactured by Cerulean Chemical Co., Ltd., "1220") and 2.5 parts of sodium salt of naphthalenesulfonic acid formaldehyde condensate (manufactured by Kao Chemical Co., Ltd., "Demol N") to 300 parts of ion-exchanged water, and stir at 1500 rpm for 15 minutes using a disperser. Then, add 52.5 parts of graphite (manufactured by Nippon Graphite Co., Ltd., "JB-5") and 13.0 parts of carbon black (manufactured by Denka Co., Ltd., "Li400"), and stir at 2000 rpm for 30 minutes using a disperser. Further add 27 parts of conductive adhesive binder II (based on solids equivalent), and stir at 1500 rpm for 15 minutes to obtain a coating liquid for the first adhesive layer.

[0272] The first adhesive layer was coated onto a copper current collector with a thickness of 10 μm and a width of 30 cm using a contact gravure method at a coating speed of 10 m / min and a drying temperature of 120 °C. The resulting first adhesive layer had a film thickness of 0.5 μm, a coating width of 25 cm in the width direction, and an adhesion strength of 0.02 N.

[0273] (2-2. Second adhesive layer)

[0274] The above-mentioned adhesive material II for the second adhesive layer is mixed in such a way that the solid content is 30% and the nonionic surfactant DISPANOL TOC (manufactured by Nippon Oil Co., Ltd.) is 0.5%, thereby obtaining the coating liquid for the second adhesive layer.

[0275] The second adhesive layer was coated onto the current collector on which the first adhesive layer was formed using a coating liquid via direct gravure printing at a coating speed of 40 m / min and a drying temperature of 50°C. The resulting second adhesive layer had a film thickness of 0.3 μm, a coating width of 25.5 cm in the width direction, and an adhesive strength of 1.7 N.

[0276] (2-3. Positive electrode)

[0277] Add 97 parts of NMC532 (LiNi), a Co-Ni-Mn lithium composite oxide active material, as the positive electrode active material, to a planetary mixer. 0.5 Co 0.2 Mn 0.3O2), 1 part acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., product name "Li-400") as a conductive material, and 2 parts (solid component equivalent) polyvinylidene fluoride (manufactured by Kureha Co., Ltd., product name "#7208") as a binder were mixed. N-methyl-2-pyrrolidone (NMP) as an organic solvent was then slowly added, and the mixture was stirred at 25±3°C and 25 rpm to obtain a positive electrode slurry composition with a viscosity (using a type B viscometer, temperature: 25±3°C, rotor: M4, rotor speed: 60 rpm) of 3600 mPa·s.

[0278] A notched roller coater was used to apply a coating at a rate of 20.0 ± 0.5 mg / cm³. 2 The obtained positive electrode slurry composition was coated onto an aluminum foil with a thickness of 15 μm, which served as a current collector. The mixture was then conveyed at a speed of 0.2 m / min in an oven at 120°C for 2 minutes, and then further conveyed in an oven at 130°C for 2 minutes to dry the slurry composition on the aluminum foil, thereby obtaining a positive electrode raw material with a positive electrode composite layer formed on the current collector.

[0279] Then, one side of the cathode composite material layer of the prepared cathode raw material was rolled at a temperature of 25±3℃ to obtain a cathode composite material layer with a density of 3.50 g / cm³. 3 The positive pole.

[0280] (2-4. Composite particles for negative electrode)

[0281] 97.4 parts of natural graphite (median particle size on a volume basis: 22 μm, theoretical capacity: 360 mAh / g) as the negative electrode active material and 1.0 part (solids equivalent) of ammonium salt of carboxymethyl cellulose (Daicel Fine Chemicals Co., Ltd., product number "DN-800H") were added to a planetary mixer. The solids concentration of the contents of the mixer was further diluted to 60% with deionized water, and then the mixture was kneaded at a rotation speed of 45 rpm for 60 minutes. Then, 1.5 parts (solids equivalent) of particulate polymer II as a binder II for the electrode composite layer were added, and the contents of the mixer were kneaded at a rotation speed of 40 rpm for 40 minutes. Then, deionized water was added to achieve a viscosity (using a type B viscometer, temperature: 25°C, rotor speed: 60 rpm) of 1000 ± 200 mPa·s, thereby preparing a slurry composition for the negative electrode.

[0282] The obtained negative electrode slurry composition was fed into a spray dryer (manufactured by Okawahara Chemical Machinery Co., Ltd., product name "L-8i"), and spray dried using a Sharp Edge atomizer (manufactured by Okawahara Chemical Machinery Co., Ltd., diameter 65mm) at a rotation speed of 25,000 rpm, a hot air temperature of 180°C, and a particle recovery outlet temperature of 90°C to obtain composite particles for negative electrodes with a median particle size of 70 μm on a volume basis.

[0283] (2-5. Negative electrode)

[0284] The aforementioned composite particles for the negative electrode are fed into the pressing rollers of a roller press (manufactured by Nikka Spray KV, Nikka Corporation) using a metering feeder (50°C, 500 kN / m pressing line pressure) (manufactured by Hirano Giken Kogyo, Ltd.). Copper foil with the aforementioned first and second adhesive layers is inserted between the pressing rollers, causing the composite particles supplied from the metering feeder to adhere to the copper foil. Pressing is then performed at a forming speed of 5.0 m / min. This yields a negative electrode having a copper foil as a current collector and a negative electrode composite material layer formed on one side of the copper foil. The weight per unit area of ​​the negative electrode composite material layer is 10.5 mg / cm². 2 Its density is 1.60 g / cm³. 3 .

[0285] [Example 12]

[0286] The thickness of the first adhesive layer of the negative electrode was set to 0.3 μm, and the thickness of the second adhesive layer was further set to 3 μm. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 11 and evaluated.

[0287] [Example 13]

[0288] The thickness of the first adhesive layer of the negative electrode was set to 5 μm. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 11 and evaluated.

[0289] [Example 14]

[0290] The amount of sodium dodecylbenzenesulfonate, used as an emulsifier, was changed to 0.15 parts. Otherwise, an aqueous dispersion of a second adhesive layer binder material (glass transition temperature Tg: -40°C) with a median particle size of 0.85 μm (by volume) was obtained using the same method as in Manufacturing Example 4. Using this aqueous dispersion of the second adhesive layer binder material instead of the second adhesive layer binder material I obtained in Manufacturing Example 4, the thickness of the second adhesive layer was set to 0.9 μm. Otherwise, a lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0291] [Example 15]

[0292] The ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer was set to 60%. Otherwise, the lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0293] [Example 16]

[0294] The ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer was set to 25%. Otherwise, the lithium-ion secondary battery was manufactured and evaluated in the same manner as in Example 1.

[0295] [Comparative Example 1]

[0296] The thickness of the first adhesive layer of the positive electrode was set to 2.5 μm, and no second adhesive layer was provided. Otherwise, the lithium-ion secondary battery was manufactured in the same manner as in Example 1 and evaluated.

[0297] [Comparative Example 2]

[0298] The first adhesive layer without a positive electrode is not provided; that is, the second adhesive layer is directly provided on the current collector layer. Otherwise, the lithium-ion secondary battery is manufactured in the same manner as in Example 1 and evaluated.

[0299] <Results>

[0300] The results of the above-described embodiments and comparative examples are shown in the following tables. In the tables below, the abbreviations have the following meanings.

[0301] NMC532: LiNi 0.5 Co 0.2 Mn 0.3 O2

[0302] Hydroxides of SIS: Hydroxides of styrene-isoprene-styrene copolymers used as polymer I

[0303] CMC: Ammonium salt of carboxymethyl cellulose

[0304] ACR1: An acrylate polymer used as adhesive material I in the first adhesive layer.

[0305] ACR2: An acrylate polymer used as adhesive material I in the second adhesive layer.

[0306] SBR1: Styrene-butadiene copolymer used as particulate polymer II

[0307] SBR2: A styrene-butadiene copolymer used as an adhesive material for a second adhesive layer.

[0308] Particle size D50: Median particle size of composite particles or polymers

[0309] Tg1 (°C): Glass transition temperature of the adhesive material contained in the first adhesive layer

[0310] Tg2 (°C): The glass transition temperature of the adhesive material contained in the second adhesive layer.

[0311] Coverage (%): The ratio of the area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer.

[0312] Contact adhesion ratio (second conductive layer / first conductive layer): The ratio of the contact adhesion value of the second conductive layer to the contact adhesion value of the first conductive layer.

[0313] [Table 1]

[0314]

[0315] [Table 2]

[0316]

[0317] [Table 3]

[0318]

[0319] [Table 4]

[0320]

[0321] [Table 5]

[0322]

[0323] [Table 6]

[0324]

[0325] As shown in Examples 1-13 and Examples 14-16, it was confirmed that an electrode having a conductive adhesive layer, and wherein the conductive adhesive layer has a first adhesive layer and a second adhesive layer, can achieve both reduced IV resistance and high-speed molding performance. On the other hand, it was confirmed that, as shown in Comparative Example 1, while a reduction in IV resistance is achieved when only the first adhesive layer is present, sufficient high-speed molding performance is not obtained; as shown in Comparative Example 2, while good high-speed molding performance is obtained when only the second adhesive layer is present, the IV resistance becomes higher. Furthermore, it was confirmed that the high-temperature storage performance of lithium-ion batteries using the electrodes shown in Examples 1-13 and Examples 14-16 is improved.

[0326] Explanation of reference numerals in the attached figures

[0327] 1: Current collector layer;

[0328] 2: Conductive adhesive layer;

[0329] 3: Electrode composite material layer;

[0330] 21: First adhesive layer;

[0331] 22: Second adhesive layer.

Claims

1. An electrode for a non-aqueous secondary battery, comprising sequentially a current collector layer, a conductive adhesive layer, and an electrode composite material layer. The electrode composite layer includes electrode active materials and binder materials. The conductive adhesive layer has: A first adhesive layer, disposed on the current collector layer; and A second adhesive layer is provided such that it partially covers the first adhesive layer and is in contact with the electrode composite material layer. The first adhesive layer comprises conductive particles and a bonding material. The second adhesive layer comprises conductive particles and a binder material, and the proportion of the conductive particles is lower than that of the first adhesive layer; or The second adhesive layer contains an adhesive material but does not contain conductive particles.

2. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The electrode composite material layer contains composite particles containing electrode active materials and binder materials.

3. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The second adhesive layer contains an adhesive material but does not contain conductive particles.

4. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The second adhesive layer is regularly disposed on a portion of the surface of the first adhesive layer.

5. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The second adhesive layer is partially disposed on the surface of the current collector layer on the side where the first adhesive layer is disposed.

6. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The area of ​​the first adhesive layer covered by the second adhesive layer is more than 20% and less than 80% of the total area of ​​the first adhesive layer.

7. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The thickness t1 of the first adhesive layer is greater than 0.1 μm and less than 3.0 μm.

8. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The thickness t2 of the second adhesive layer is greater than 0.1 μm and less than 2.0 μm.

9. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The ratio (t2 / t1) of the thickness t2 of the second adhesive layer to the thickness t1 of the first adhesive layer is 0.1 or more and 10 or less.

10. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The adhesive material contained in the second adhesive layer is granular, and the median particle size of the adhesive material is greater than 0.01 μm and less than 1 μm.

11. The electrode for a non-aqueous secondary battery according to claim 1, wherein, The glass transition temperature Tg1 of the adhesive material contained in the first adhesive layer is above -30°C and below 25°C, and the glass transition temperature Tg2 of the adhesive material contained in the second adhesive layer is above -50°C and below -10°C, wherein Tg1 is greater than Tg2.

12. The electrode for a non-aqueous secondary battery according to any one of claims 1 to 11, wherein, The contact adhesion of the conductive adhesive layer surface is greater than 0.1N and less than 3.0N.

13. A non-aqueous secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte. At least one of the positive electrode and the negative electrode is the electrode for a non-aqueous secondary battery as described in claim 1 or 2.

14. A method for manufacturing an electrode for a non-aqueous secondary battery, wherein the electrode for a non-aqueous secondary battery is the electrode for a non-aqueous secondary battery as described in claim 1. The manufacturing method includes: Step (A) involves performing a step (A1) of setting the first adhesive layer on the current collector layer and a step (A2) of partially setting the second adhesive layer on the first adhesive layer, thereby setting the conductive adhesive layer on the current collector layer. as well as Step (B) involves supplying composite particles containing electrode active material and adhesive material to the second adhesive layer of the conductive adhesive layer, applying pressure, and setting an electrode composite material layer.

15. The method for manufacturing an electrode for a non-aqueous secondary battery according to claim 14, wherein, The current collector layer is a long strip. The width S1 of the region on the current collector layer where the first adhesive layer is disposed and the width S2 of the region where the second adhesive layer is disposed satisfy the relationship expressed by the following formula (1). 。

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