Nonaqueous secondary battery electrode, method for manufacturing same, and nonaqueous secondary battery

Abstract

This nonaqueous secondary battery electrode includes a current collector layer, a conductive adhesive layer, and an electrode mixture layer in the stated order. The electrode mixture layer contains an electrode active material and a binder. The conductive adhesive layer includes a first adhesive layer provided on the collector layer, and a second adhesive layer that is provided so as to partially cover the first adhesive layer and that is in contact with the electrode mixture layer. The first adhesive layer contains conductive particles and a binder. The second adhesive layer contains conductive particles and a binder. The second adhesive layer contains the conductive particles at a proportion lower than the first adhesive layer, or the second adhesive layer contains a binder and does not contain conductive particles. A method for manufacturing a nonaqueous secondary battery electrode and a nonaqueous secondary battery are also provided.

Description

Electrode for non-aqueous secondary battery, method for manufacturing the same, and non-aqueous secondary battery

[0001] The present invention relates to an electrode for a non-aqueous secondary battery, a method for producing the same, and a non-aqueous secondary battery.

[0002] Non-aqueous secondary batteries, such as non-aqueous lithium-ion secondary batteries, typically include electrodes such as a positive electrode and a negative electrode. Electrodes for non-aqueous secondary batteries typically include a current collector and an electrode mixture layer containing an electrode active material provided on the surface of the current collector. Such electrodes are typically formed by preparing a slurry containing materials constituting the electrode mixture layer and a solvent, applying the slurry to the surface of the current collector to form a slurry layer, and then drying the layer.

[0003] However, in recent years, electrode manufacturing methods using dry processes that use powdered materials have been attracting attention (Patent Documents 1 to 4).

[0004] JP 2010-108971 A JP 2014-078497 A (corresponding publications: U.S. Patent Application Publication No. 2014 / 079872 and U.S. Patent Application Publication No. 2015 / 0194680) JP 2013-012393 A (corresponding publications: U.S. Patent Application Publication No. 2013 / 0004843) WO 2015 / 115177

[0005] In a method for manufacturing an electrode using a dry process, for example, composite particles containing an electrode active material and a binder are deposited on a current collector and then pressure-molded to produce an electrode mixture layer. However, because the composite particles have low adhesion to the current collector, electrodes manufactured using the dry process may tend to have high resistance. In addition, because the composite particles deposited on the current collector move freely around the current collector during pressure molding, for example, in order to mold an electrode mixture layer having a desired thickness using roll pressure molding, it is necessary to limit the molding speed, making it difficult to increase productivity.

[0006] For example, Patent Document 1 discloses providing a conductive adhesive layer containing carbon particles between a current collector and an electrode mixture layer. While this technique can reduce the resistance of the electrode, it is difficult to sufficiently increase the adhesion of the composite particles to the current collector, making it difficult to increase the molding speed during roll pressure molding. Furthermore, Patent Document 2 discloses improving the adhesion of the composite particles to the current collector by applying a binder in a pattern between the current collector and the electrode mixture layer. While this technique can increase the molding speed during roll pressure molding, it tends to increase the resistance between the current collector and the electrode active material. Therefore, even when using conventional techniques, it has been difficult to achieve both low electrode resistance and high-speed moldability.

[0007] The present invention has been made in view of the above-mentioned circumstances, and aims to provide an electrode for a non-aqueous secondary battery which has low resistance and can be produced by increasing the pressure molding speed during electrode molding, i.e., has good high-speed formability; a method for producing an electrode for a non-aqueous secondary battery which can produce an electrode with low resistance by increasing the molding speed; and a non-aqueous secondary battery equipped with the electrode for a non-aqueous secondary battery.

[0008] The present invention is as follows.

[0009] [1] An electrode for a non-aqueous secondary battery comprising, in this order, a current collector layer, a conductive adhesive layer, and an electrode mixture layer, wherein the electrode mixture layer contains an electrode active material and a binder, and the conductive adhesive layer has 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 mixture layer, wherein the first adhesive layer contains conductive particles and a binder, and the second adhesive layer contains conductive particles and a binder, and the content of the conductive particles is lower than that of the first adhesive layer, or the second adhesive layer contains a binder but does not contain conductive particles. [2] The electrode for a non-aqueous secondary battery according to [1], wherein the electrode mixture layer contains composite particles containing an electrode active material and a binder. [3] The electrode for a non-aqueous secondary battery according to [1] or [2], wherein the second adhesive layer contains a binder but does not contain conductive particles. [4] The electrode for a non-aqueous secondary battery according to any one of [1] to [3], wherein the second adhesive layer is regularly provided on a partial region of the surface of the first adhesive layer. [5] The electrode for a non-aqueous secondary battery according to any one of [1] to [4], wherein the second adhesive layer is partially provided on the surface of the current collector layer on the side on which the first adhesive layer is provided. [6] The electrode for a non-aqueous secondary battery according to any one of [1] to [5], wherein 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 is 20% to 80%. [7] The 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 to 3.0 μm. [8] The 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 to 2.0 μm. [9] The electrode for a non-aqueous secondary battery according to any one of [1] to [8], wherein a ratio (t2 / t1) of a thickness t2 of the second adhesive layer to a 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 any one of [1] to [9], wherein the binder contained in the second adhesive layer is particulate, and the median diameter of the binder is 0.1 μm or more and 1 μm or less.

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

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

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

[11] , wherein the tackiness of the surface of the conductive adhesive layer is higher than 0.1 N and not higher than 3.0 N.

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

[12] .

[14] The method for producing an electrode for a non-aqueous secondary battery according to any one of [1] to

[12] , comprising: step (A) of providing the conductive adhesive layer on the current collector layer by performing step (A1) of providing the first adhesive layer on a current collector layer and step (A2) of partially providing the second adhesive layer on the first adhesive layer; and step (B) of supplying composite particles containing an electrode active material and a binder onto the second adhesive layer of the conductive adhesive layer and applying pressure to provide an electrode mixture layer.

[15] The method for producing an electrode for a non-aqueous secondary battery according to

[14] , wherein the current collector layer is long, and a width S1 of the region on the current collector layer where the first adhesive layer is provided and a width S2 of the region on the current collector layer where the second adhesive layer is provided satisfy the relationship represented by the following formula (1): 100≦S2 / S1×100≦110 (1).

[0010] According to the present invention, it is possible to provide an electrode for a non-aqueous secondary battery that has low resistance and is easy to form at high speed, a method for manufacturing an electrode for a non-aqueous secondary battery that can manufacture an electrode with low resistance by increasing the forming speed, and a non-aqueous secondary battery equipped with the electrode for a non-aqueous secondary battery.

[0011] Fig. 1 is a cross-sectional view schematically showing an electrode according to an embodiment of the present invention. Fig. 2 is a cross-sectional view schematically showing a conductive adhesive layer according to an embodiment of the present invention. Fig. 3 is a plan view schematically showing a conductive adhesive layer according to an embodiment of the present invention.

[0012] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0013] In the following description, in a polymer produced by copolymerizing a plurality of types of monomers, the ratio of a monomer unit formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of the certain monomer to all the monomers used in the polymerization of the polymer, unless otherwise specified.

[0014] In the following description, the structure of a molecule or a part thereof, such as a monomer unit, is not limited by its production method. For example, an aromatic vinyl monomer unit is a unit having a structure formed by polymerization of an aromatic vinyl monomer, but the aromatic vinyl monomer unit also includes units formed by other formation methods that have the same structure as the structure formed by polymerization of an aromatic vinyl monomer.

[0015] 1. Overview of Electrode for Non-Aqueous Secondary Battery Fig. 1 is a cross-sectional view schematically 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 may be simply referred to as an "electrode." As shown in Fig. 1, an electrode 10 according to one embodiment of the present invention includes a current collector layer 1, a conductive adhesive layer 2, and an electrode mixture layer 3, in this order. In the electrode 10, the electrode mixture layer 3 is a layer containing an electrode active material and a binder.

[0016] 1 , in the electrode 10, the conductive adhesive layer 2 includes a first adhesive layer 21 provided on the current collector layer 1 and a second adhesive layer 22 provided so as to partially cover the first adhesive layer 21 and in contact with the electrode mixture layer 3. The first adhesive layer 21 is a layer containing conductive particles and a binder. The second adhesive layer 22 is either a layer having the following configuration (a) or (b):

[0017] (a) A layer containing conductive particles and a binder, and having a lower content of conductive particles than the first adhesive layer 21. (b) A layer containing a binder, but not containing conductive particles.

[0018] When the conductive adhesive layer 2 is a layer having the configuration (a) or (b) as the second adhesive layer, the content of the binder in the second adhesive layer is usually higher than the content of the binder in the first adhesive layer.

[0019] According to the present invention, by providing a conductive adhesive layer having a first adhesive layer and a second adhesive layer, the resistance is reduced and an electrode having good high-speed formability can be obtained.

[0020] The inventors speculate as follows about the mechanism by which the electrode according to one embodiment of the present invention can achieve both reduced electrode resistance and high-speed formability, although the technical scope of the present invention is not limited by the mechanism described below.

[0021] Generally, electrodes having an electrode mixture layer formed by compressing composite particles containing an electrode active material and a binder in a dry process tend to have high contact resistance between the current collector layer and the electrode active material in the electrode mixture layer. In contrast, the electrode according to the present embodiment has a structure in which the current collector layer and the electrode mixture layer are laminated via a first adhesive layer containing conductive particles in a region of the conductive adhesive layer where the second adhesive layer is not provided. This laminate structure can sufficiently reduce the contact resistance between the electrode active material in the electrode mixture layer and the first adhesive layer, and can also sufficiently reduce the contact resistance between the first adhesive layer and the current collector layer. Thus, the inventors of the present embodiment speculate that the electrode according to the present embodiment can sufficiently reduce the resistance between the current collector layer and the electrode active material in the electrode mixture layer in a region where the second adhesive layer is not provided by interposing the first adhesive layer therebetween, thereby reducing the overall resistance of the electrode even when the second adhesive layer is partially disposed.

[0022] Furthermore, in the electrode according to this embodiment, a second adhesive layer having a relatively higher binder content than the first adhesive layer is partially provided on the first adhesive layer, which allows the friction coefficient of the surface of the conductive adhesive layer to be sufficiently large. Therefore, the inventors infer that when composite particles are supplied to the surface of the conductive adhesive layer and pressure is applied, the movement of the composite particles can be restricted, and an electrode composite layer can be formed to the desired thickness even if the pressure forming speed (forming speed) is increased.

[0023] Furthermore, while studying the electrode according to this embodiment, the present inventors have unexpectedly found that the electrode according to this embodiment exhibits the effect of improving the high-temperature storage stability of non-aqueous secondary batteries. The present inventors speculate on the mechanism behind this as follows. However, the technical scope of the present invention is not limited by the mechanism described below.

[0024] Conductive particles are substances that can reduce the resistance between the current collector layer and the electrode active material, but they are also thought to be a factor in the deterioration of non-aqueous secondary batteries (for example, the starting point for the deterioration of the electrode active material or the deterioration of the electrolyte at high temperatures). In contrast, in this embodiment, a portion of the binder in the second adhesive layer provided on the first adhesive layer penetrates into the first adhesive layer and coats a portion of the surface of the conductive particles. As a result, the conductive adhesive layer can coat the surfaces of the conductive particles with the binder to an extent that can suppress the deterioration of the non-aqueous secondary battery while maintaining good conductivity between the current collector layer and the electrode active material in the electrode mixture layer, and the inventors speculate that this can improve the high-temperature storage stability of the non-aqueous secondary battery.

[0025] Hereinafter, each configuration of the electrode according to this embodiment will be described.

[0026] [2. Current Collector Layer] The material for the current collector layer is preferably a material that is electrically conductive and electrochemically durable. Specific examples of materials that can be used for 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 alloys thereof. Among these, copper, aluminum, and aluminum alloys are preferred in terms of conductivity and voltage resistance. When high voltage resistance is required, high-purity aluminum as disclosed in JP-A-2001-176757 can be preferably used. Among these, aluminum is preferred as the material for the current collector layer that can be used for the positive electrode, and copper is preferred as the material for the current collector layer that can be used for the negative electrode. These materials may be used alone or in combination of two or more.

[0027] The current collector layer generally has a film or sheet shape. The thickness of the current collector layer may be appropriately selected depending on the intended use, and is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0028] [3. Conductive Adhesive Layer] The conductive adhesive layer has 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 mixture layer.

[0029] [3.1. First Adhesive Layer] The first adhesive layer is a layer provided on the current collector layer, and contains at least conductive particles and a binder.

[0030] The conductive particles that can be contained in the first adhesive layer are particles made of a conductive material. Examples of conductive particles include metal particles and carbon particles. Among these, the conductive particles are preferably carbon particles, because they can effectively reduce the resistance between the current collector layer and the electrode active material. Furthermore, since the inclusion of carbon particles tends to reduce the high-temperature storage stability of non-aqueous secondary batteries, the inclusion of carbon particles can also result in a non-aqueous secondary battery with good high-temperature storage stability.

[0031] Examples of carbon particles include graphite (specifically, natural graphite, artificial 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 black, thermal lamp black, etc.), which is a spherical aggregate in which several layers of graphitic carbon crystallites gather to form a turbostratic structure; carbon fiber; and carbon whiskers. Among these, graphite or carbon black is particularly preferred because the carbon particles in the first adhesive layer are densely packed, reducing electron transfer resistance and further reducing the internal resistance of the nonaqueous secondary battery. The carbon particles exemplified above may be used alone or in combination of two or more types.

[0032] The median diameter 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, and for example, 10 μm or less, preferably 8 μm or less, more preferably 6 μm or less. The median diameter of the conductive particles can be determined by measuring the particle size of the particles using a laser diffraction particle size distribution analyzer (SALD-3100; manufactured by Shimadzu Corporation) and determining the particle size (D50) at which the cumulative volume calculated from the smallest diameter side in the obtained particle size distribution (volume basis) becomes 50%.

[0033] The content of the conductive particles in the first adhesive layer is, for example, typically 40% by mass or more, preferably 50% by mass or more, and more preferably 60% by mass or more, relative to the solid content contained in the first adhesive layer, and typically 99.9% by mass or less, preferably 90% by mass or less, and more preferably 80% by mass or less.

[0034] The binder that can be contained in the first adhesive layer is a compound that can bind conductive particles to each other and can bind conductive particles to the current collector layer. A polymer is typically used as such a binder. The polymer used as the binder may be a water-insoluble polymer. Unless otherwise specified, a polymer being "water-insoluble" means that when 0.5 g of the polymer is dissolved in 100 g of water at 25°C, the insoluble content is 90 mass% or more. Preferred examples of binders include polymers such as acrylate-based polymers, conjugated diene-based polymers, and fluorine-based polymers, with acrylate-based polymers and conjugated diene-based polymers being particularly preferred. This is because the withstand voltage can be increased and the energy density of non-aqueous secondary batteries can be increased. Furthermore, this is because the binder has excellent binding strength.

[0035] The acrylate polymer is represented by the general formula (1): CH ２ =CR １ -COOR ２ (In the formula, R １ represents a hydrogen atom or a methyl group, R ２ represents an alkyl group or a cycloalkyl group. ２may further have an ether group, a hydroxyl group, a phosphoric acid group, an amino group, a carboxyl group, a fluorine atom, or an epoxy group.) The acrylate polymer is a polymer containing a monomer unit (hereinafter sometimes referred to as an "acrylate monomer unit") having a structure formed by polymerizing a monomer [(meth)acrylic acid ester] represented by general formula (1). Specifically, this acrylate polymer may be a homopolymer of a monomer represented by general formula (1) or a copolymer obtained by polymerizing a monomer mixture containing the monomer represented by general formula (1).Specific examples of the monomer compound represented by general formula (1) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. (meth)acrylic acid alkyl esters such as ethylhexyl (meth)acrylate, hexyl (meth)acrylate, nonyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and tridecyl (meth)acrylate; (meth)acrylic acid alkyl esters such as butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, ether group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate; carboxylic acid-containing (meth)acrylic acid esters such as 2-(meth)acryloyloxyethyl phthalate and 2-(meth)acryloyloxyethyl phthalate; fluorine group-containing (meth)acrylic acid esters such as perfluorooctylethyl (meth)acrylate; phosphate group-containing (meth)acrylic acid esters such as ethyl (meth)acrylate phosphate; epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; and amino group-containing (meth)acrylic acid esters such as dimethylaminoethyl (meth)acrylate. As used herein, the term "(meth)acrylic" encompasses "acrylic" and "methacrylic," and the term "(meth)acryloyl" encompasses "acryloyl" and "methacryloyl."

[0036] The monomers represented by general formula (1) can be used alone or in combination of two or more. Among these, (meth)acrylic acid alkyl esters are preferred. Furthermore, methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate; as well as (meth)acrylic acid alkyl esters having an alkyl group with 6 to 12 carbon atoms; are more preferred. By selecting these, it is possible to reduce swelling in the electrolyte solution, thereby improving cycle characteristics.

[0037] The proportion of acrylate monomer units in the acrylate polymer is usually 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, and the upper limit is usually 100% by mass or less, and may be 98% by mass or less or 95% by mass or less.

[0038] The acrylate polymer may contain a copolymerizable carboxylic acid group-containing monomer in addition to the monomer represented by general formula (1). Therefore, the acrylate polymer may contain a monomer unit having a structure formed by polymerizing a carboxylic acid group-containing monomer. Specific examples of the carboxylic acid group-containing monomer include monobasic acid-containing monomers such as acrylic acid and methacrylic acid; and dibasic acid-containing monomers such as maleic acid, fumaric acid, and itaconic acid. The amount of the carboxylic acid group-containing monomer used in copolymerization is typically 0.1 parts by weight or more, preferably 0.5 parts by weight or more, and more preferably 1 part by weight or more, relative to 100 parts by weight of the monomer represented by general formula (1), and typically 50 parts by weight or less, preferably 30 parts by weight or less, and more preferably 10 parts by weight or less.

[0039] The acrylate polymer may contain a copolymerizable nitrile group-containing monomer in addition to the monomer represented by general formula (1). Therefore, the acrylate polymer may contain a monomer unit having a structure formed by polymerizing the nitrile group-containing monomer. Specific examples of the nitrile group-containing monomer include acrylonitrile and methacrylonitrile. The amount of the copolymerizable nitrile group-containing monomer is typically 0.1 parts by weight or more, preferably 0.5 parts by weight or more, and more preferably 1 part by weight or more, relative to 100 parts by weight of the monomer represented by general formula (1), and typically 40 parts by weight or less, preferably 30 parts by weight or less, and more preferably 10 parts by weight or less.

[0040] Conjugated diene polymers are homopolymers of conjugated dienes, copolymers obtained by polymerizing a monomer mixture containing conjugated dienes, or hydrogenated products thereof. Therefore, conjugated diene polymers may contain one or more monomer units (hereinafter sometimes referred to as "conjugated diene monomer units") selected from the group consisting of monomer units having a structure formed by polymerizing a conjugated diene and monomer units having a structure formed by hydrogenating the polymerized conjugated diene. Preferred conjugated dienes include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, substituted linear conjugated pentadiene, and substituted and side-chain conjugated hexadienes. 1,3-butadiene is more preferred because it can improve the flexibility and crack resistance of the resulting electrode. Furthermore, the monomer mixture may contain two or more of these conjugated dienes.

[0041] When the conjugated diene polymer is a copolymer of the above-mentioned conjugated diene and a monomer copolymerizable therewith, examples of such copolymerizable monomer include an α,β-unsaturated nitrile compound and a vinyl compound having an acid component.

[0042] Specific examples of the conjugated diene polymer include conjugated diene homopolymers such as polybutadiene (BR) and polyisoprene (IR); aromatic vinyl-conjugated diene copolymers such as styrene-butadiene copolymer (SBR) and styrene-isoprene copolymer (SIR), which may be carboxy-modified; copolymers of aromatic vinyl-conjugated diene-carboxylic acid group-containing monomer such as styrene-butadiene-methacrylic acid copolymer and styrene-butadiene-itaconic acid copolymer; vinyl cyanide-conjugated diene copolymers such as acrylonitrile-butadiene copolymer (NBR); block polymers such as styrene-butadiene-styrene copolymer (SBS) and styrene-isoprene-styrene (SIS); and hydrogenated conjugated diene polymers such as hydrogenated SBR, hydrogenated NBR, hydrogenated SBS, and hydrogenated SIS.

[0043] 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, and preferably 80% by mass or less, more preferably 70% by mass or less. By having the proportion of conjugated diene monomer units equal to or less than the upper limit, the electrolyte resistance can be improved when the resulting electrode is formed. By having the proportion of conjugated diene monomer units equal to or more than the lower limit, sufficient adhesion between the composite particles and the current collector layer can be ensured.

[0044] A fluoropolymer is a polymer containing a monomer unit containing a fluorine atom. Specific examples of the fluoropolymer include polytetrafluoroethylene, polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and perfluoroethylene-propene copolymer. Among these, PVDF is preferred.

[0045] Furthermore, as the binder, for example, a polymer that can be contained in the electrode mixture layer described below can also be used.

[0046] The glass transition temperature Tg1 of the binder that can be contained in the first adhesive layer is, for example, -30°C or higher, preferably -20°C or higher, more preferably -15°C or higher, and for example, 25°C or lower, preferably 20°C or lower, more preferably 15°C or lower. Having a glass transition temperature Tg1 within the above range allows for good bonding between the conductive particles and between the current collector layer and the conductive particles. This also increases the strength of the first adhesive layer, thereby suppressing deformation of the conductive adhesive layer during electrode production and battery use. The glass transition temperature of the binder can be measured using a differential scanning calorimeter at a heating rate of 20°C / min in accordance with JIS K 7121:1987.

[0047] Furthermore, the glass transition temperature Tg1 of the binder contained in the first adhesive layer is preferably higher than the glass transition temperature Tg2 of the binder contained in the second adhesive layer, which will be described later. This is because the magnitude relationship between Tg1 and Tg2 makes it easier to obtain a conductive adhesive layer that has high layer strength and a large coefficient of friction on the surface on the electrode mixture layer side.

[0048] The shape of the polymer (binder) that can be contained in the first adhesive layer is not particularly limited, but it is preferably particulate. This is because even a small amount can exhibit excellent binding strength and improve the strength of the first adhesive layer. The median diameter of the polymer (binder) particles can be, for example, 0.01 μm or more and 1.0 μm or less. The median diameter of the polymer particles can be determined, for example, by measuring the particle size of the particles using a laser diffraction particle size distribution analyzer, and taking the particle size (D50) at which the cumulative volume calculated from the smallest diameter side in the obtained particle size distribution (volume basis) becomes 50%.

[0049] The content of the binder in the first adhesive layer 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, and for example, 60 parts by weight or less, preferably 50 parts by weight or less, more preferably 45 parts by weight or less, relative to 100 parts by weight of the conductive particles. When the content of the binder in the first adhesive layer is equal to or greater than the lower limit, the conductive particles can be well bound together, as well as between the current collector layer and the conductive particles. Furthermore, when the content of the binder in the first adhesive layer is equal to or less than the upper limit, the resistance between the current collector layer and the electrode active material can be effectively reduced.

[0050] The first adhesive layer contains at least conductive particles and a binder, and may further contain optional components as needed. Examples of the optional components include carboxymethyl cellulose and a surfactant. Examples of the carboxymethyl cellulose and surfactant include those described in JP 2010-108971 A.

[0051] The first adhesive layer is usually provided in direct contact with the current collector layer without any other layer therebetween, and is usually disposed over the entire area where the electrode mixture layer is to be disposed.

[0052] The thickness of the first adhesive layer can be set to a thickness sufficient to ensure the conductivity of the current collector layer and the electrode mixture layer. The thickness of the first adhesive layer is usually 0.1 μm or more, preferably 0.2 μm or more, and more preferably 0.3 μm or more, and usually 3.0 μm or less, preferably 2.0 μm or less, and more preferably 1.0 μm or less. When the thickness of the first adhesive layer is equal to or greater than the lower limit, the resistance between the current collector layer and the electrode active material can be effectively reduced. Furthermore, when the thickness of the first adhesive layer is equal to or less than the upper limit, the tackiness of the surface of the conductive adhesive layer can be improved, thereby improving high-speed formability. Furthermore, high-temperature storage stability can be improved.

[0053] 1 , the thickness of the first adhesive layer refers to the distance t1 in the thickness direction from the surface of the adhesive layer 21 on the current collector layer side 1 to the surface on which the second adhesive layer 2 is formed. The thickness of the first adhesive layer 21 may differ between the portion on which the second adhesive layer 22 is formed and the portion on which 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 on which 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 with a transmission electron microscope.

[0054] The tackiness 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. The higher the tackiness of the surface of the first adhesive layer in the conductive adhesive layer, the better, but it is usually about 0.1 N or less.

[0055] The tackiness of the surface of the first adhesive layer in the conductive adhesive layer can be measured by preparing a sample in which the first adhesive layer is provided on a current collector layer, pressing a 5 mm diameter probe against the surface of the first adhesive layer of the sample at a speed of 1 mm / sec, holding the probe thereon for 10 seconds, and then lifting the probe at a speed of 1 mm / sec, as the maximum load. This measurement can be performed, for example, using a tackiness tester ("TAC-1000" manufactured by Rhesca Co., Ltd.). The sample can also be a first adhesive layer provided on a current collector layer during the electrode manufacturing process.

[0056] [3.2. Second adhesive layer] The second adhesive layer is a layer partially provided on the first adhesive layer and in contact with the electrode mixture layer. The second adhesive layer is either a layer having the following configuration (a) or (b):

[0057] (a) a layer containing conductive particles and a binder, and having a lower content of conductive particles than the first adhesive layer; (b) a layer containing a binder, but not containing conductive particles.

[0058] When the second adhesive layer is a layer having the configuration (a), the second adhesive layer usually contains at least a binder and conductive particles, and may contain optional components as necessary. Furthermore, in this embodiment, when the second adhesive layer contains conductive particles, the content of the conductive particles in the second adhesive layer is usually lower than the content of the conductive particles in the first adhesive layer.

[0059] The content of the conductive particles in the second adhesive layer is typically greater than 0% by mass and at least 0.1% by mass relative to the solid content of the second adhesive layer, and is, for example, 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, relative to the solid content of the second adhesive layer.

[0060] On the other hand, when the second adhesive layer has the structure (b) described above, the second adhesive layer does not contain conductive particles but contains a binder, and may contain optional components as necessary. In addition, the second adhesive layer usually does not contain any conductive material other than the conductive particles.

[0061] In this embodiment, it is more preferable that the second adhesive layer is the layer having the configuration (b) of the layers having the configurations (a) and (b), that is, the second adhesive layer contains a binder but does not contain conductive particles. By not containing conductive particles in the second adhesive layer, the binder content on the surface of the conductive adhesive layer facing the electrode mixture layer can be increased, thereby increasing the coefficient of friction, and effectively restricting the movement of the composite particles during electrode production, enabling the electrode to be formed at a higher speed.

[0062] The conductive particles that may be contained in the second adhesive layer may be appropriately selected from those described as the conductive particles that may be contained in the first adhesive layer. In this embodiment, the conductive particles contained in the first adhesive layer may be referred to as conductive particles 1, and the conductive particles contained in the second adhesive layer may be referred to as conductive particles 2. Furthermore, conductive particles 1 and conductive particles 2 may be the same type or different types.

[0063] The binder that can be contained in the second adhesive layer preferably has a glass transition temperature Tg2 within a predetermined range. Specifically, the glass transition temperature Tg2 of the binder that can be contained 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 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 having the glass transition temperature Tg2 within the above range can improve the strength of the second adhesive layer and its adhesion to the composite particles. Furthermore, the glass transition temperature Tg2 of the binder contained in the second adhesive layer is preferably lower than the glass transition temperature Tg1 of the binder contained in the first adhesive layer.

[0064] The shape of the binder that may be contained in the second adhesive layer is not particularly limited, but is preferably particulate. This is because even a small amount can exhibit excellent binding strength and improve the strength of the second adhesive layer. Furthermore, the good strength of the second adhesive layer makes it easy to physically restrict the movement of the composite particles, thereby effectively restricting particle movement during electrode production. The median diameter of the binder particles is usually 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, and is usually 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 diameter of the binder particles contained in the second adhesive layer is preferably smaller than the median diameter of the conductive particles contained in the first adhesive layer.

[0065] The binder that can be contained in the second adhesive layer can be appropriately selected from the polymers described as the binder that can be contained in the first adhesive layer. In this embodiment, the binder contained in the first adhesive layer may be referred to as binder 1, and the binder contained in the second adhesive layer may be referred to as binder 2. Furthermore, binder 1 and binder 2 may be the same type or different types.

[0066] The optional component that may be contained in the second adhesive layer may be appropriately selected from the polymers described as the optional components that may be contained in the first adhesive layer. In this embodiment, the optional component contained in the first adhesive layer may be referred to as optional component 1, and the optional component contained in the second adhesive layer may be referred to as optional component 2. Furthermore, optional component 1 and optional component 2 may be the same type or different types.

[0067] The second adhesive layer is provided directly on the first adhesive layer. A layer being "directly" provided on another layer means that there is no other layer between the two layers, unless otherwise specified. The second adhesive layer is also provided partially on the first adhesive layer. In this embodiment, the second adhesive layer is preferably provided regularly on a partial area of ​​the surface of the first adhesive layer. This is because the second adhesive layer can be easily manufactured using a printing method or the like. Furthermore, it is easy to manufacture an electrode with low resistance by adjusting the balance between the area on the conductive adhesive layer where the second adhesive layer is provided and the area where the second adhesive layer is not provided.

[0068] When the second adhesive layer is regularly provided on a portion of the surface of the first adhesive layer, the second adhesive layer may have, for example, a linear shape when viewed in the thickness direction, and may be provided in a stripe pattern in which areas where the second adhesive layer is provided and areas where the second adhesive layer is not provided are alternately arranged. Alternatively, instead of linear second adhesive layers, rectangular second adhesive layers may be arranged in a dashed stripe pattern. For example, the second adhesive layer may have at least one of a circular, elliptical, or polygonal shape, and multiple second adhesive layers may be arranged at predetermined intervals. The second adhesive layer may also be regularly provided, for example, in the pattern coating shape described in JP 2014-078497 A.

[0069] Furthermore, the second adhesive layer may be provided at least on the first adhesive layer. However, it is preferable that the second adhesive layer be partially provided on the surface of the current collector layer on the side where the first adhesive layer is provided. Specifically, as shown in FIG. 2 , the second adhesive layer 22 is preferably provided continuously on the first adhesive layer 21 and the current collector layer 1 so as to cover the end of the first adhesive layer 21. Generally, due to the structure, composite particles tend to be difficult to retain at the end of an electrode. Therefore, if an electrode mixture layer is provided on a first adhesive layer containing a large amount of conductive particles at the end of the electrode, the first adhesive layer may not be able to sufficiently bind and retain the composite particles, which may result in peeling of the electrode mixture layer. In contrast, by providing a second adhesive layer with good binding strength continuously on the first adhesive layer and the current collector layer, the binding strength between the composite particles contained in the electrode mixture layer and the second adhesive layer can be increased, thereby effectively suppressing peeling of the electrode mixture layer at the end of the electrode. Furthermore, when a nonaqueous secondary battery is fabricated using the electrode and stored at high temperatures, deterioration originating from peeled portions of the electrode mixture layer at the ends of the electrode can be suppressed, thereby improving the high-temperature storage properties of the battery. When the second adhesive layer is provided so as to cover the ends of the first adhesive layer, the second adhesive layer is provided so as to cover at least a portion of the ends of the first adhesive layer. For example, when the electrode has a long shape, it is preferable that the second adhesive layer is provided so as to cover two ends located in the width direction of the first adhesive layer.

[0070] The degree to which the second adhesive layer partially covers the first adhesive layer can be appropriately selected depending 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 of the first adhesive layer) is usually 20% or more, preferably 30% or more, and more preferably 40% or more. The coverage of the first adhesive layer is usually 80% or less, preferably 70% or less, and more preferably 50% or less. When the coverage of the first adhesive layer is equal to or greater than the lower limit, high-speed formability can be improved, and when the coverage of the first adhesive layer is within the above range, low resistance and high-speed formability of the electrode can be effectively achieved.

[0071] The thickness of the second adhesive layer is usually 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.3 μm or more, and usually 2.0 μm or less, preferably 1.0 μm or less, more preferably 0.8 μm or less. Having the thickness of the second adhesive layer within this range increases the strength of the second adhesive layer. Furthermore, since irregularities can be provided on the surface of the conductive adhesive layer facing the second adhesive layer, it is easy to restrict the movement of the composite particles during electrode production, improving high-speed moldability.

[0072] In this embodiment, the first adhesive layer and the second adhesive layer are preferably provided so 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, and preferably 10 or less, more preferably 3 or less, and even more preferably 1 or less. When the thickness ratio (t2 / t1) is equal to or greater than the lower limit, the desired high-speed formability can be stably obtained, and when the thickness ratio is equal to or less than the upper limit, a significant resistance reduction effect can be obtained.

[0073] The thickness of the second adhesive layer refers to the distance t2 in the thickness direction from the surface of second adhesive layer 22 on the side of first adhesive layer 21 to the surface on which electrode mixture layer 3 is formed. The thickness of the second adhesive layer can be determined, for example, by observing the cross section of the electrode with a transmission electron microscope.

[0074] The tackiness 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. The higher the tackiness of the surface of the second adhesive layer in the conductive adhesive layer, the better, but it is, for example, about 3.0 N or less.

[0075] The tackiness of the second adhesive layer surface in the conductive adhesive layer is usually higher than the tackiness of the first adhesive layer surface in the conductive adhesive layer. In one example, the ratio of the tackiness of the second adhesive layer surface to the tackiness of the first adhesive layer surface (second adhesive layer / first adhesive layer) is usually greater than 1.0, preferably 30 or more, more preferably 70 or more, even more preferably 120 or more, and preferably 150 or more. The upper limit can be, for example, 300 or less, preferably 220 or less, and more preferably 170 or less.

[0076] The tackiness of the surface of the second adhesive layer in the conductive adhesive layer can be measured by preparing a sample in which a first adhesive layer is provided on a current collector layer and a second adhesive layer is partially provided on the first adhesive layer, and measuring the surface of the second adhesive layer of the sample in the same manner as for the tackiness of the first adhesive layer. As a sample, a sample in which the second adhesive layer is provided on the first adhesive layer on the current collector layer during the manufacturing process of the electrode can also be used.

[0077] [3.3. Tackiness of the Conductive Adhesive Layer] The tackiness of the conductive adhesive layer surface in this embodiment is typically, for example, greater than 0.1 N, preferably 0.3 N or greater, and more preferably 0.4 N or greater. The higher the tackiness of the conductive adhesive layer surface in the conductive adhesive layer, the more preferable, but it is, for example, approximately 3.0 N or less. The tackiness of the conductive adhesive layer can be measured by preparing a sample having a conductive adhesive layer having a first adhesive layer and a second adhesive layer on a current collector layer, and measuring the surface of the second adhesive layer of the sample using the same method as for measuring the tackiness of the first adhesive layer. Having the tackiness of the conductive adhesive layer surface within the above range effectively achieves both low resistance and high-speed formability of the non-aqueous secondary battery electrode. The tackiness of the conductive adhesive layer surface typically has the same value as the tackiness of the second adhesive layer surface.

[0078] [4. Electrode mixture layer] The electrode mixture layer is a layer provided on the conductive adhesive layer, and is a layer containing an electrode active material and a binder. In this embodiment, the electrode mixture layer is usually produced using composite particles containing an electrode active material and a binder, and therefore the electrode mixture layer can contain composite particles. Furthermore, when the electrode mixture layer further contains an optional component described below, it is preferably produced using composite particles containing the optional component, and therefore the electrode mixture layer preferably contains composite particles containing the optional component.

[0079] The electrode active material can be appropriately selected depending on the type of non-aqueous secondary battery. The electrode active material may be a positive electrode active material or a negative electrode active material. When the non-aqueous secondary battery is a lithium ion secondary battery, an example of the positive electrode active material is a metal oxide that can reversibly dope and dedope lithium ions. Examples of such metal oxides include lithium cobalt oxide (LiCoO ２ ), lithium nickel oxide (LiNiO ２ ), lithium manganese oxide (LiMn ２ O ４ ), lithium iron phosphate (LiFeO ４ ), ternary active materials in which part of lithium cobalt oxide is replaced with nickel and manganese (for example, LiCo １／３ Ni １／３ Mn １／３ O ２ , LiNi ０．５ Co ０．２ Mn ０．３ O ２ The positive electrode active material may be used alone or in combination of two or more.

[0080] When the nonaqueous secondary battery is a lithium ion secondary battery, examples of the negative electrode active material include low-crystalline carbon (amorphous carbon) (e.g., graphitizable carbon, non-graphitizable carbon, pyrolytic carbon); graphite (e.g., natural graphite, artificial graphite); alloy-based materials containing tin, silicon, etc.; oxides (e.g., silicon oxide, tin oxide, lithium titanate); etc. The negative electrode active material may be used alone or in combination.

[0081] The electrode active material is preferably in the form of particles, which allows the electrode active material to be molded into a high-density electrode.

[0082] The median diameter 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. When the median diameter of the electrode active material is within the above range, it can be suitably used as a material for a lithium ion battery electrode. The median diameter of the electrode active material is a volume-based median diameter, and can be measured using a method similar to the method for measuring the median diameter of the polymer described above.

[0083] The content of the electrode active material in the electrode mixture layer is preferably 90% by mass or more, more preferably 92% by mass or more, even more preferably 95% by mass or more, and preferably 99.5% by mass or less, more preferably 99% by mass or less, even more preferably 98.5% by mass or less. When the content of the electrode active material is equal to or greater than the lower limit, a high electrochemical device capacity can be obtained. When the content of the electrode active material is equal to or less than the upper limit, good high-temperature storage characteristics can be obtained. When the electrode mixture layer contains composite particles, the content of the electrode active material in 100% by mass of the composite particles can be within the above-mentioned numerical range.

[0084] A polymer is usually used as the binder that can be contained in the electrode mixture layer. The polymer as the binder may be a water-insoluble polymer. Preferred examples of the binder that can be contained in the electrode mixture layer include polymers such as acrylate-based polymers, conjugated diene-based polymers, and fluorine-based polymers. From the viewpoint of the molding speed when producing an electrode for a non-aqueous secondary battery by pressure molding composite particles containing an electrode active material and a binder by a dry process, a conjugated diene-based polymer is preferred.

[0085] The fluoropolymer that can be contained in the electrode mixture layer can be appropriately selected from the polymers explained as the fluoropolymer that can be contained in the first adhesive layer.

[0086] The conjugated diene polymer that can be contained in the electrode mixture layer can be appropriately selected from the polymers explained as the conjugated diene polymer that can be contained in the first adhesive layer.

[0087] As described above, the acrylate polymer is a polymer containing a monomer unit having a structure formed by polymerizing a monomer [(meth)acrylic acid ester] represented by general formula (1). The monomer represented by general formula (1) can be appropriately selected from the monomers described as the monomers of the acrylate polymer that the first adhesive layer can contain. The (meth)acrylic acid esters as the monomer represented by general formula (1) can be used alone or in combination of two or more. Among these, (meth)acrylic acid alkyl esters are preferred, with methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate; and (meth)acrylic acid alkyl esters having an alkyl group with 6 to 12 carbon atoms being more preferred. By selecting these, it is possible to reduce swelling in the electrolyte solution and improve cycle characteristics.

[0088] The proportion of acrylate monomer units in the acrylate polymer is usually 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, and the upper limit is usually 100% by mass or less, and may be 98% by mass or less or 95% by mass or less.

[0089] Furthermore, when the acrylate polymer is a copolymer of a monomer represented by the above-mentioned general formula (1) and a monomer copolymerizable therewith, examples of such copolymerizable monomers include carboxylic acid esters having two or more carbon-carbon double bonds, aromatic vinyl monomers, amide monomers, olefins, diene monomers, vinyl ketones, and heterocycle-containing vinyl compounds, as well as α,β-unsaturated nitrile compounds and vinyl compounds having an acid component.

[0090] Among the copolymerizable monomers, aromatic vinyl monomers are preferred because they can be used to produce electrodes that are less likely to deform during production and have high strength, and also because they can provide sufficient adhesion between the conductive adhesive layer and the current collector. Examples of aromatic vinyl monomers include styrene.

[0091] When the acrylate polymer contains an aromatic vinyl monomer, the proportion of the aromatic vinyl monomer 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, and for example, 40% by mass or less, preferably 30% by mass or less, more preferably 30% by mass or less. This is because, when the proportion of the aromatic vinyl monomer is within the above numerical range, the adhesion between the active material layer and the conductive adhesive layer can be sufficiently increased.

[0092] As the binder, for example, a polymer that can be contained in the binder of the first adhesive layer can also be used.

[0093] In this embodiment, the electrode mixture layer is usually produced using composite particles containing the above-described electrode active material and binder, and therefore the electrode mixture layer can contain composite particles containing the above-described electrode active material and binder.

[0094] The content of the binder in the electrode mixture 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, and is 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 mixture layer contains composite particles, the content of the binder in 100% by mass of the composite particles can be within the above-mentioned numerical range.

[0095] The electrode mixture layer contains at least an electrode active material and a binder, and may further contain optional components as needed, such as carboxymethyl cellulose, a water-soluble polymer containing an acidic functional group, and a conductive material.

[0096] The electrode mixture layer may contain, for example, carboxymethyl cellulose as an optional component. From the viewpoint of obtaining the effect as a thickener and obtaining good high-temperature storage properties and good cycle properties, the molecular weight of carboxymethyl cellulose is preferably greater than 50,000, preferably greater than 100,000. The upper limit of the molecular weight is not particularly limited, but may be, for example, 1,000,000 or less. The molecular weight may be a weight-average molecular weight. The molecular weight may be measured by a measurement method such as GPC. The content of carboxymethyl cellulose in the electrode mixture layer is preferably 0.3% by mass or more and 5% by mass or less. When the electrode mixture layer contains composite particles, the content of carboxymethyl cellulose in 100% by mass of the composite particles may be within the above-mentioned numerical range.

[0097] The electrode mixture layer may contain, as an optional component, a water-soluble polymer containing an acidic functional group. A polymer is "water-soluble" when 0.5 g of the polymer is dissolved in 100 g of water at 25°C, and the insoluble content is less than 1.0 mass%.

[0098] The acidic functional group-containing water-soluble polymer may be a polymer containing a monomer unit formed by polymerization of a monomer having an acidic functional group and a polymerizable unsaturated bond. The acidic functional group-containing water-soluble polymer may be a polymer other than carboxymethyl cellulose. Examples of such polymers include polyacrylic acid, polymethacrylic acid, polyitaconic acid, polymaleic acid, polyfumaric acid, poly2-hydroxyethyl acrylate (PHEA), poly2-hydroxyethyl methacrylate (PHEMA), and mixtures thereof. Among these, polyacrylic acid, polymethacrylic acid, polyitaconic acid, poly2-hydroxyethyl acrylate, and mixtures thereof are preferred, with polymethacrylic acid being more preferred. By using such preferred polymers, good cycle characteristics can be obtained.

[0099] The molecular weight of the acidic functional group-containing water-soluble polymer is usually 1,500 or more, preferably 2,500 or more, more preferably 5,000 or more, and usually 50,000 or less, preferably 30,000 or less, more preferably 20,000 or less. The molecular weight is a weight average molecular weight. The molecular weight can be measured by a measurement method such as GPC.

[0100] The content of the acidic functional group-containing water-soluble polymer in the electrode mixture layer is preferably 0.01 mass% or more and 1.0 mass% or less. When the electrode mixture layer contains composite particles, the content of the acidic functional group-containing water-soluble polymer in 100 mass% of the composite particles can be within the above-mentioned range.

[0101] The electrode mixture layer may contain a conductive material as an optional component. The conductive material is a component for ensuring electrical contact between electrode active materials. Examples of conductive materials include carbon black (e.g., acetylene black, Ketjen Black (registered trademark), furnace black, etc.), single-walled or multi-walled carbon nanotubes (multi-walled carbon nanotubes include cup-stacked carbon nanotubes), carbon nanohorns, vapor-grown carbon fibers, milled carbon fibers obtained by calcining and then crushing polymer fibers, single-walled or multi-walled graphene, conductive carbon materials such as carbon nonwoven fabric sheets obtained by calcining nonwoven fabrics made of polymer fibers, and various metal fibers or foils. These materials can be used alone or in combination of two or more. Among these, it is preferable that the conductive material contains carbon nanotubes (hereinafter sometimes referred to as "CNT"). Typically, CNTs tend to aggregate easily and are difficult to disperse. However, when the electrode mixture layer contains the optional acidic functional group-containing water-soluble polymer, even conductive materials containing CNTs can be dispersed well.

[0102] When the electrode mixture layer contains composite particles, the composite particles may contain a solvent as an optional component. The amount of the solvent contained in the composite particles is usually 10% by mass or less, preferably 5% by mass or less, and more preferably 2% by mass or less.

[0103] The median diameter of the composite particles that can be contained in the electrode mixture layer is usually 0.1 μm or more, preferably 10 μm or more, more preferably 40 μm or more, and usually 200 μm or less, preferably 150 μm or less, more preferably 100 μm or less. The median diameter of the composite particles can be adjusted appropriately by selecting the material of the composite particles and adjusting the granulation conditions. The median diameter of the composite particles can be determined by measuring the particle size of the particles using a laser diffraction / scattering particle size distribution measuring device (for example, Nikkiso Co., Ltd., product name "Microtrac MT-3200II"), and determining the particle size (D50) at which the cumulative volume calculated from the smallest diameter side in the obtained particle size distribution (volume basis) becomes 50%.

[0104] The method for producing the composite particles is not particularly limited, and the composite particles can be produced by a known production method. For example, the composite particles can be produced by the production method described in WO 2019 / 039560 or WO 2021 / 172208.

[0105] The electrode mixture layer is usually provided directly on the conductive adhesive layer, and is provided over the entire area where the conductive adhesive layer is disposed.

[0106] The thickness of the electrode mixture layer can be appropriately selected depending on the application of the nonaqueous secondary battery.

[0107] The amount of the electrode mixture layer per unit area is sometimes referred to as the "basis weight." There is no limitation on the basis weight of the electrode mixture layer, but in one example, it is usually 1 mg / cm ２ or more, preferably 2 mg / cm ２ More preferably, 5 mg / cm ２ or more, usually 100 mg / cm ２ Preferably 50 mg / cm or less ２ or less, more preferably 30 mg / cm ２ The following is the result.

[0108] 5. Method for Producing an Electrode for a Non-Aqueous Secondary Battery The electrode for a non-aqueous secondary battery according to one embodiment of the present invention can be produced by any method, but is preferably produced by a production method including the following steps (A) and (B). Hereinafter, this production method will be described as the method for producing an electrode for a non-aqueous secondary battery of the present invention.

[0109] Step (A): A step of providing a conductive adhesive layer on a current collector layer by carrying out Step (A1) of providing a first adhesive layer on the current collector layer, and Step (A2) of partially providing a second adhesive layer on the first adhesive layer. Step (B): A step of supplying composite particles containing an electrode active material and a binder onto the second adhesive layer of the conductive adhesive layer, and applying pressure to provide an electrode mixture layer.

[0110] According to the present invention, by providing a conductive adhesive layer on a collector layer, the movement of composite particles supplied onto the conductive adhesive layer can be restricted, thereby increasing the speed at which the electrode composite layer is formed by pressure, thereby enabling the production of an electrode.

[0111] [5.1. Step (A): Step of Providing a Conductive Adhesive Layer] Step (A) includes step (A1) of providing a first adhesive layer on the current collector layer, and step (A2) of partially providing a second adhesive layer on the first adhesive layer. By performing steps (A1) and (A2), a conductive adhesive layer can be provided on the current collector layer.

[0112] The current collector layer used in step (A) is preferably long. Here, a long current collector layer refers to a current collector having a length that is 5 times or more its width, preferably 10 times or more its width, and specifically refers to a current collector layer having a length that is long enough to be wound into a roll for storage or transportation. There is no particular upper limit to the length of the current collector layer, and it can be, for example, 100,000 times or less its width.

[0113] In step (A1), the first adhesive layer can be formed on the current collector layer by, for example, preparing a coating solution containing the material for the first adhesive layer, applying the coating solution to the current collector layer, and drying the resulting coating to form the first adhesive layer. Examples of solvents that can be used in the coating solution include ion-exchanged water.

[0114] The method for applying the coating liquid is not particularly limited, and any known method can be used, specifically, a doctor blade method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, etc. The thickness of the coating film can be appropriately set depending on the thickness of the first adhesive layer obtained after drying.

[0115] The coating film of the first adhesive layer can be dried by a known drying method, such as drying with warm air, hot air, or low-humidity air, vacuum drying, or drying by irradiation with (far) infrared rays or electron beams. 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 shorter.

[0116] In step (A2), a method for partially providing a second adhesive layer on the first adhesive layer includes, for example, preparing a coating liquid containing the material for the second adhesive layer, partially applying the coating to the first adhesive layer, and drying the resulting coating to form the second adhesive layer. The coating liquid for the second adhesive layer can be applied by any printing method that can partially provide the second adhesive layer on the first adhesive layer, such as inkjet printing, gravure printing, or screen printing. The thickness of the coating can be appropriately set depending on the thickness of the second adhesive layer obtained by drying. 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.

[0117] In step (A2), for example, as shown in Fig. 3 , linear second adhesive layers arranged in stripes obliquely to the conveying direction MD of the current collector layer 1 (the longitudinal direction of the current collector layer 1) may be provided on the first adhesive layer 21. This is because providing the second adhesive layers in stripes obliquely to the conveying direction of the current collector layer makes it easier to restrict the movement of the composite particles supplied in step (B). Fig. 3 shows an example in which a plurality of linear second adhesive layers are provided, but although not shown, rectangular second adhesive layers may also be arranged to provide the second adhesive layers in dashed stripes.

[0118] The direction oblique to the conveying direction of the current collector layer generally refers to a direction perpendicular to the thickness direction, which is neither the longitudinal direction nor the width direction of the current collector layer.

[0119] The second adhesive layer is provided so as to at least partially cover the first adhesive layer. For example, as shown in Fig. 3, when the current collector layer 1 is long, 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 preferably satisfy the relationship expressed by the following formula (1). This is because the strength of the end portions in the width direction of the conductive adhesive layer can be increased, and the bonding strength between the current collector layer and the conductive adhesive layer, as well as the bonding strength between the conductive adhesive layer and the electrode mixture layer, can be improved. 100≦S2 / S1×100≦110 (1)

[0120] Formula (1) will be explained in more detail. "S2 / S1×100" is preferably 100 or more, more preferably 100.5 or more, and preferably 110 or less, more preferably 105 or less, and even more preferably 103 or less. When "S2 / S1×100" is in such a range, the high-temperature storage stability of the secondary battery can be significantly improved.

[0121] 3 , the width S1 of the region where the first adhesive layer 21 is provided refers to the widthwise distance of the region where the first adhesive layer 21 is provided in the width direction of the long 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 provided on the end-most sides of the current collector layer 1 in the width direction.

[0122] When the width S1 of the region where the first adhesive layer is provided on the current collector layer and the width S2 of the region where the second adhesive layer is provided satisfy the relationship expressed by the above formula (1), the first adhesive layer and the second adhesive layer are usually provided so that the region where the second adhesive layer is provided overlaps at least the entire region where the first adhesive layer is provided.

[0123] [5.2. Step (B): Step of Providing an Electrode Mixture Layer] Step (B) is a step of supplying composite particles containing an electrode active material and a binder onto the second adhesive layer of the conductive adhesive layer obtained in step (A), and applying pressure to provide an electrode mixture layer.

[0124] There are no limitations on the form of the binder that may be contained in the composite particles supplied onto the second adhesive layer. Therefore, when a polymer is used as the binder, the polymer may be a particulate polymer or a non-particulate polymer. The particulate polymer is a polymer particle described above as a binder that may be contained in the electrode mixture layer. The non-particulate polymer is a polymer that does not have a particulate form, and may have, for example, an irregular shape. Such a non-particulate polymer may be, for example, a soluble polymer that can be dissolved in the solvent used in the production of the composite particles, or may be an irregular polymer formed by drying the solvent during the production process of the composite particles. In one example, a non-particulate polymer may be used as the binder for the positive electrode, and a particulate polymer may be used as the binder for the negative electrode. The volume-based median diameter of the particulate polymer is, for example, 40 nm or more, preferably 50 nm or more, more preferably 70 nm or more, and, for example, 500 nm or less, preferably 400 nm or less, more preferably 300 nm or less.

[0125] A method for supplying the composite particles onto the second adhesive layer of the conductive adhesive layer includes, for example, transporting a collector layer provided with a conductive adhesive layer with a roll and supplying the composite particles onto the transported collector layer using a known supply device.

[0126] As a method for pressurizing the composite particles to provide an electrode mixture layer, a method using a roll-type pressure molding device equipped with a pair of rolls is usually mentioned. In the present invention, the movement of the composite particles supplied onto the conductive adhesive layer can be restricted while performing roll pressure molding, so that the molding speed can be increased.

[0127] The temperature during roll pressure molding 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 pressure molding is preferably 0.2 kN / cm or higher, more preferably 1.5 kN / cm or higher, and preferably 30 kN / cm or lower, more preferably 15 kN / cm or lower. By keeping the linear pressure within the above range, the uniformity of the thickness of the electrode mixture layer can be improved.

[0128] The forming speed during roll pressure forming is preferably 10 m / min or more, more preferably 30 m / min or more, and is preferably 70 m / min or less, more preferably 50 m / min or less.

[0129] Furthermore, in order to eliminate variations in the thickness of the formed electrode and increase the density of the electrode active material layer to achieve high capacity, further pressure may be applied after forming. The pressure application method in this case is usually performed by a roll pressing process. In the roll pressing process, generally, two cylindrical rolls are arranged parallel to each other with a narrow gap between them, and are rotated in opposite directions to pressurize the electrode by sandwiching it between them. In this case, the temperature of the rolls may be adjusted, for example, by heating or cooling, as necessary.

[0130] 6. Modifications In the present invention, the following electrode, for example, can be provided as an electrode having reduced resistance and good high-speed formability.

[0131] An electrode for a non-aqueous secondary battery, comprising a current collector layer, a conductive adhesive layer, and an electrode mixture layer in this order, wherein the conductive adhesive layer has a tackiness of greater than 0.1 N on the surface facing the electrode mixture layer.

[0132] According to the modified example, the conductive adhesive layer is conductive and has high tackiness on the electrode composite layer side, which reduces resistance and allows pressure molding to be performed by restricting the movement of the composite particles during electrode manufacturing, resulting in an electrode with high high-speed moldability.

[0133] The tackiness of the conductive adhesive layer is usually greater than 0.1 N, preferably 0.3 N or more, and more preferably 0.4 N or more. The higher the tackiness of the surface of the second adhesive layer in the conductive adhesive layer, the better, but it is, for example, about 3.0 N or less. The tackiness of the conductive adhesive layer can be measured by preparing a sample in which a conductive adhesive layer is provided on a current collector layer, and measuring the tackiness of the conductive adhesive layer surface of the sample in the same manner as for the tackiness of the first adhesive layer.

[0134] The conductive adhesive layer preferably has a surface facing the electrode mixture layer that exhibits the aforementioned tackiness and exhibits conductivity in the thickness direction of the layer. Examples of such a conductive adhesive layer include a layer containing conductive particles and a binder. Furthermore, a two-layer conductive adhesive layer having the aforementioned first and second adhesive layers can also be considered as a conductive adhesive layer in a modified example.

[0135] The modified example may be the same as that described for the electrode according to the above embodiment, except that it has the conductive adhesive layer having tackiness.

[0136] 7. Nonaqueous Secondary Battery The nonaqueous secondary battery according to the present invention is a nonaqueous secondary battery including a positive electrode, a negative electrode, and an electrolyte, and at least one of the positive electrode and the negative electrode is the above-described electrode for a nonaqueous secondary battery.

[0137] The nonaqueous secondary battery according to the present invention includes the aforementioned electrode for a nonaqueous secondary battery, thereby enabling a nonaqueous secondary battery with reduced electrode resistance. Furthermore, since a nonaqueous secondary battery can be manufactured using an electrode with excellent high-speed formability, the nonaqueous secondary battery can be highly productive. Furthermore, by including the electrode according to the present invention, the secondary battery can be made to have good high-temperature storage stability.

[0138] When the nonaqueous secondary battery is a lithium ion secondary battery, the electrolyte solution can be an electrolyte solution prepared by dissolving an electrolyte in a solvent. Here, an organic solvent capable of dissolving the electrolyte can be used as the solvent. Specifically, the solvent can be an alkyl carbonate solvent such as ethylene carbonate, propylene carbonate, or γ-butyrolactone to which a viscosity-adjusting solvent such as 2,5-dimethyltetrahydrofuran, tetrahydrofuran, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, methyl acetate, dimethoxyethane, dioxolane, methyl propionate, or methyl formate has been added. A lithium salt can be used as the electrolyte. For example, the lithium salts described in JP 2012-204303 A can be used. Among these lithium salts, LiPF 6 is preferred as the electrolyte because it is easily soluble in organic solvents and exhibits a high degree of dissociation. ６, LiClO ４ , C.F. ３ SO ３ Li is preferred.

[0139] Furthermore, the nonaqueous secondary battery may further include a separator as needed. Examples of separators that can be used include those described in JP 2012-204303 A. Among these, a microporous film made of a polyolefin resin (polyethylene, polypropylene, polybutene, polyvinyl chloride) is preferred because it allows the overall separator thickness to be thin, thereby increasing the proportion of electrode active material in the lithium ion secondary battery and increasing capacity per volume.

[0140] A nonaqueous secondary battery can be manufactured, for example, by stacking a positive electrode and a negative electrode with a separator interposed therebetween, rolling or folding the stack as necessary according to the battery shape, placing the stack in a battery container, injecting an electrolyte into the battery container, and sealing the battery container. To prevent internal pressure rise and overcharging / discharging, etc., a fuse, an overcurrent prevention element such as a PTC element, an expanded metal, a lead plate, etc. may be provided as necessary. The shape of the secondary battery may be any type, such as a coin type, a button type, a sheet type, a cylindrical type, a rectangular type, or a flat type.

[0141] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the examples shown below, and can be practiced with any modifications within the scope of the claims of the present invention and their equivalents.

[0142] In the following description, "%" representing an amount is based on mass unless otherwise specified. In the following description, "parts" representing an amount is based on weight unless otherwise specified. In addition, the operations described below were carried out under conditions of room temperature and normal pressure unless otherwise specified.

[0143] [Evaluation Method] <Tack Strength (Tackiness)> In the Examples and Comparative Examples, the tackiness of the surface of the adhesive layer provided on the current collector layer was measured. Specifically, in the Examples, the tackiness of the surface of the first adhesive layer provided on the current collector layer was measured, as well as the tackiness of the surface of the second adhesive layer in a conductive adhesive layer having a first adhesive layer provided on the current collector layer and a second adhesive layer provided on the first adhesive layer was measured. In the Examples, the tackiness of the surface of the second adhesive layer can also be evaluated as the tackiness of the surface of a two-layer conductive adhesive layer. Meanwhile, in the Comparative Examples, the tackiness of the surface of the first adhesive layer or the second adhesive layer provided on the current collector layer was measured. The tackiness was measured using a "TAC-1000" manufactured by Rhesca Co., Ltd. Specifically, a 5 mm diameter probe (made of SUS) was pressed against the conductive adhesive layer at a speed of 1 mm / sec with a load of 4000 gf, held for 10 seconds, and then pulled up at a speed of 1 mm / sec, and the maximum load was measured. The larger the value, the better the tack strength.

[0144] <High-Speed ​​Formability> In the examples and comparative examples, composite particles (granulated particles) were supplied onto a conductive adhesive layer provided on a current collector layer, and electrodes were produced by increasing the conveying speed using a roll press machine described below. The resulting electrodes were inspected for appearance, and the maximum forming speed at which streaks and chipping did not occur was evaluated according to the following criteria: A: 50 m / min or more B: 30 m / min or more but less than 50 m / min C: 10 m / min or more but less than 30 m / min D: Less than 10 m / min

[0145] <I-V Characteristics> After injecting the electrolyte, the lithium ion secondary batteries in the examples and comparative examples were left standing at 25°C for 5 hours. Next, they were charged to a cell voltage of 3.65 V using a constant current method at 0.2 C at 25°C, and then aged for 12 hours at 60°C. Then, they were discharged to a cell voltage of 3.00 V using a constant current method at 0.2 C at 25°C. Then, they were subjected to CC-CV charging (upper limit cell voltage 4.35 V) using a constant current method at 0.2 C, and CC discharged to 3.00 V using a constant current method at 0.2 C. This 0.2 C charge-discharge cycle was repeated three times. Then, they were charged to an SOC of 50% at 0.2 C in a 25°C environment, and the voltage V0 was measured after leaving them standing for 3 hours in a 25°C environment. Thereafter, discharge was performed at a discharge rate of 1C, and the voltage V1 was measured 10 seconds after the start of discharge. The low-temperature IV resistance (mΩ) was calculated as (V0-V1) / 40 x 1000, and evaluated according to the following criteria. The smaller this value, the better the low-temperature IV resistance. A: 40mΩ or less B: Over 40mΩ, 42mΩ or less C: Over 42mΩ, 44mΩ or less D: Over 44mΩ, 46mΩ or less E: Over 46mΩ

[0146] <High-Temperature Storage Characteristics> The lithium-ion secondary batteries in the examples and comparative examples were charged to a cell voltage of 4.2 V using a constant current method of 0.5 C in a 25°C atmosphere, and then discharged to 3.0 V, and the initial discharge capacity C0 was measured. Next, the lithium-ion secondary batteries were charged to a cell voltage of 4.2 V using a constant current method of 0.5 C in a 25°C atmosphere. Thereafter, these lithium-ion secondary batteries were stored in a 60°C atmosphere for 3 weeks (high-temperature storage). After high-temperature storage, the batteries were discharged to 3 V using a constant current method of 0.5 C in a 25°C atmosphere, and the remaining capacity C1 after high-temperature storage was measured. The capacity retention rate (%) = (remaining capacity C1 / initial discharge capacity C0) × 100 was then calculated and evaluated according to the following criteria. A higher capacity retention rate indicates a lithium-ion secondary battery with better high-temperature storage characteristics. A: Capacity retention rate is 90% or more. B: Capacity retention rate is 85% or more and less than 90%. C: Capacity retention rate is 80% or more and less than 85%. D: Capacity retention rate is 75% or more and less than 80%. E: Capacity retention rate is less than 75%.

[0147] <Thickness of First Adhesive Layer and Second Adhesive Layer> The thickness of the first adhesive layer and the second adhesive layer was determined by using a microtome to cut a cross section with a glass blade and observing the cross section with a transmission electron microscope.

[0148] <Median diameter of polymer particles> The median diameter of polymer particles was measured by a laser diffraction method. Specifically, an aqueous dispersion solution (solid content concentration 0.1% by mass) containing the prepared particulate polymer was used as a sample, and the particle size was determined as the particle size at which the cumulative volume calculated from the smallest diameter side in the particle size distribution (volume basis) obtained using a laser diffraction particle size distribution analyzer (manufactured by Beckman Coulter, Inc., product name "LS-13 320") accounted for 50%.

[0149] [Production Example 1: Method for producing binder I (SIS hydride) for electrode composite layer] 270 parts of dehydrated cyclohexane and 0.53 parts of ethylene glycol dibutyl ether were placed in a reactor equipped with a stirrer and the inside of which was thoroughly purged with nitrogen, and 0.47 parts of n-butyllithium (15% cyclohexane solution) was further added. While stirring the entire contents at 60 ° C, 12.5 parts of dehydrated styrene were continuously added to the reactor over 40 minutes. After the addition was completed, the entire contents were stirred for an additional 20 minutes at 60 ° C. When the reaction solution was measured by gas chromatography, the polymerization conversion rate at this point was 99.5%. Next, 75.0 parts of dehydrated isoprene was continuously added to the reaction solution over 100 minutes, and after the addition was completed, stirring was continued for 20 minutes. The polymerization conversion rate at this point was 99.5%. Thereafter, 12.5 parts of dehydrated styrene were continuously added over 60 minutes, and after completion of the addition, the entire solution was stirred for 30 minutes. At this point, the polymerization conversion rate was nearly 100%. Then, 0.5 parts of isopropyl alcohol was added to the reaction solution to terminate the reaction, yielding a block copolymer [C1]. Of all the isoprene-derived monomer units in the resulting block copolymer [C1], the proportion of monomer units derived from 1,2- and 3,4-addition polymerization was 58%. Next, the polymer solution was transferred to a pressure-resistant reactor equipped with a stirrer, and 7.0 parts of a diatomaceous earth-supported nickel catalyst (manufactured by JGC Catalysts and Chemicals, product name "E22U," nickel loading 60%) as a hydrogenation catalyst and 80 parts of dehydrated cyclohexane were added and mixed. The atmosphere inside the reactor was replaced with hydrogen gas, and hydrogen was further supplied while stirring the solution, and the hydrogenation reaction was carried out at a temperature of 190°C and a pressure of 4.5 MPa for 6 hours. After completion of the hydrogenation reaction, the reaction solution was filtered to remove the hydrogenation catalyst, and then 1.0 part of a xylene solution containing 0.1 part of pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by Koyo Chemical Research Institute, product name "Songnox 1010"), a phenolic antioxidant, was added to the filtrate and dissolved. Cyclohexane was further added to obtain a cyclohexane solution of polymer I having a predetermined concentration.

[0150] [Production Example 2: Method for producing binder II (SBR1) for electrode composite layer] 64 parts of styrene, 32 parts of 1,3-butadiene, 3 parts of itaconic acid, 1 part of 2-hydroxyethyl acrylate (β-hydroxyethyl acrylate), 0.3 parts of t-dodecyl mercaptan as a molecular weight modifier, 5 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water as a solvent, and 1 part of potassium persulfate as a polymerization initiator were charged into a 5 MPa pressure vessel equipped with a stirrer, and after thorough stirring, the mixture was heated to 55°C to initiate polymerization. The reaction was stopped by cooling when the monomer consumption reached 95.0%. A 5% aqueous sodium hydroxide solution was added to the aqueous dispersion containing the polymer obtained in this manner, and the pH was adjusted to 8. Subsequently, unreacted monomer was removed by heated vacuum distillation. The mixture was then cooled to a temperature of 30°C or below to obtain an aqueous dispersion containing particulate polymer II (glass transition temperature Tg: 15°C).

[0151] [Production Example 3: Method for producing a binder for the first adhesive layer (ACR1)] 90 parts of ion-exchanged water and 0.23 parts of ammonium persulfate were each supplied to a reactor equipped with a stirrer, the gas phase was replaced with nitrogen gas, and the temperature was raised to 70°C. Meanwhile, in a separate container, 50 parts of ion-exchanged water, 1.0 part of sodium dodecylbenzenesulfonate (manufactured by Kao Chemical Corporation, "Neopelex 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 to carry out polymerization. During the addition, the reaction was carried out at 80°C. After completion of the addition, the mixture was further stirred at 80°C for 3 hours to terminate the reaction. Thereafter, a 5% aqueous solution of sodium hydroxide was added to adjust the pH to 8, thereby obtaining an aqueous dispersion containing a binder for the first adhesive layer (glass transition temperature Tg: -15°C).

[0152] [Production Example 4: Method for producing second adhesive layer binder I (ACR2)] 90 parts of ion-exchanged water and 0.23 parts of ammonium persulfate were each supplied to a reactor equipped with a stirrer, the gas phase was replaced with nitrogen gas, and the temperature was raised to 70°C. Meanwhile, in a separate container, 50 parts of ion-exchanged water, 1.0 part of sodium dodecylbenzenesulfonate (manufactured by Kao Chemical Corporation, "Neopelex 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 to carry out polymerization. During the addition, the reaction was carried out at 80°C. After completion of the addition, the mixture was further stirred at 80°C for 3 hours to terminate the reaction. Thereafter, a 5% aqueous solution of sodium hydroxide was added to adjust the pH to 8, thereby obtaining an aqueous dispersion containing binder I for the second adhesive layer (glass transition temperature Tg: -40°C).

[0153] [Production Example 5: Method for producing binder II (SBR2) for second adhesive layer] 38 parts of styrene, 58 parts of 1,3-butadiene, 3 parts of itaconic acid, 1 part of 2-hydroxyethyl acrylate (β-hydroxyethyl acrylate), 0.3 parts of t-dodecyl mercaptan as a molecular weight modifier, 5 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water as a solvent, and 1 part of potassium persulfate as a polymerization initiator were charged into a 5 MPa pressure vessel equipped with a stirrer, and after thorough stirring, the mixture was heated to 55°C to initiate polymerization. When the monomer consumption reached 95.0%, the mixture was cooled to terminate the reaction. A 5% aqueous solution of sodium hydroxide was added to the aqueous dispersion containing the polymer obtained in this manner, and the pH was adjusted to 8. Subsequently, unreacted monomer was removed by heated, reduced-pressure distillation. Thereafter, the mixture was cooled to a temperature of 30° C. or less to obtain an aqueous dispersion containing a binder II for the second adhesive layer (glass transition temperature Tg: −30° C.).

[0154] [Example 1] (1-1. Preparation of First Adhesive Layer) 5.0 parts of carboxymethyl cellulose (manufactured by Daicel Miraize Co., Ltd., "1220") and 2.5 parts of sodium salt of naphthalenesulfonic acid formalin condensate (manufactured by Kao Chemical Co., Ltd., "Demol N") were added to 300 parts of ion-exchanged water, and the mixture was stirred at 1500 rpm for 15 minutes using a disper. Then, 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") were added, and the mixture was stirred at 2000 rpm for 30 minutes using a disper. Furthermore, 27 parts of binder I for the first adhesive layer, equivalent to solids, were added, and the mixture was stirred at 1500 rpm for 15 minutes to obtain a coating liquid for the first adhesive layer. The obtained coating liquid for the first adhesive layer was applied to an aluminum current collector having a thickness of 15 μm and a width of 30 cm by a kiss reverse gravure method at a coating speed of 10 m / min and a drying temperature of 120° C. The obtained first adhesive layer had a film thickness of 1.0 μm, a coating width in the width direction of 25 cm, and a tacking strength of 0.02 N.

[0155] (1-2. Preparation of Second Adhesive Layer) A coating liquid for a second adhesive layer was obtained by mixing the above-mentioned second adhesive layer binder I at 30% solids and the nonionic surfactant Dispanol TOC (manufactured by NOF Corporation) at 0.5% solids. The obtained coating liquid for a second adhesive layer was applied to the current collector layer on which the first adhesive layer had been formed by direct gravure at a coating speed of 40 m / min and a drying temperature of 50°C. At this time, the coating liquid for a second adhesive layer was applied so that the second adhesive layer was arranged in a stripe pattern at the center of the first adhesive layer. Furthermore, at the widthwise edges of the first adhesive layer, the coating liquid for a second adhesive layer was applied onto the first adhesive layer and the current collector layer so that the edges of the first adhesive layer were covered with the strip-shaped second adhesive layer. The obtained second adhesive layer had a film thickness of 0.3 μm, a widthwise coating width of 25.5 cm, and a tacking strength of 1.8 N. The ratio (%) of the width S2 of the region where the second adhesive layer coating liquid was applied to the width S1 of the region where the first adhesive layer coating liquid was applied was 102%. Also, 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%.

[0156] (1-3. Preparation of composite particles for positive electrode) A composite particle preparation device was prepared. The device was a cylindrical container with an inner diameter of 180 mm and a capacity of 2 L, which served as a granulation tank. The axial direction of the cylindrical container was the vertical direction, and the device had stirring blades on two axes, one vertical and one horizontal (the main stirring blade was the one in the vertical direction, and the auxiliary stirring blade was the one in the horizontal direction). The main stirring blade was an inclined paddle with three main blades each 170 mm in diameter, and the auxiliary stirring blade had a V-shaped anchor blade with a diameter of 30 mm. The mechanism was such that the main stirring blade and the auxiliary stirring blade were sealed by ventilating them to prevent raw materials from being mixed into the drive parts. Using the composite particle preparation device, (i) a preliminary stirring operation, (ii) a pre-composite particle formation operation, and (iii) a sizing operation were carried out in this order to prepare composite particles. First, (i) in the preliminary stirring operation, a Co—Ni—Mn lithium composite oxide active material NMC532 (LiNi) as a positive electrode active material for a lithium ion battery was placed in a granulation tank. ０．５ Co ０．２ Mn ０．３ O ２ 96 parts (1344 g) of carbon black (BET specific surface area: 62 m) as a conductive material ２ / g, bulk density 0.16 g / cm ３ ) was added. Next, room temperature air (hereinafter also referred to as "sealing air") for sealing the drive parts of the main stirring blade and the auxiliary stirring blade was circulated at 20 L / min (airflow rate 10 / min), and the mixture was stirred for 15 minutes under operating conditions of a main stirring blade peripheral speed of 5 m / s and a auxiliary stirring blade peripheral speed of 6 m / s. The solids concentration of the powder material after stirring was measured and was found to be 99% or more. Next, (ii) as a pre-composite particle formation operation, room temperature sealing air was circulated at 20 L / min (airflow rate 10 / min), and the main stirring blade peripheral speed was 5 m / s and the auxiliary stirring blade peripheral speed was 6 m / s. 2 parts (280 g) of a cyclohexane solution of polymer I (solids concentration: 10% by mass, viscosity index: 200 mPa s) as the binder I for the electrode mixture layer was continuously added as solids using a dropping funnel over 15 minutes. Next, (iii) as a particle size adjustment operation, room temperature sealing air was circulated at 20 L / min (airflow rate 10 / min), and the stirring blade was operated at a peripheral speed of 2 m / s for 10 minutes under the operating conditions of a main stirring blade and a sub stirring blade. The above operations (i) to (iii) were carried out in this order to obtain composite particles for a positive electrode.

[0157] (1-4. Preparation of Positive Electrode) The composite particles for the positive electrode obtained in (1-3) were supplied to a press roll (roll temperature 50°C, press linear pressure 1000 kN / m) of a roll press machine ("Press-Cut Rough Surface Heat Roll" manufactured by Hirano Giken Kogyo Co., Ltd.) using a quantitative feeder ("Nikka Spray K-V" manufactured by Nikka Corporation). The aluminum foil on which the first adhesive layer and the second adhesive layer were formed was inserted between the press rolls, and the composite particles supplied from the quantitative feeder were adhered thereto. The mixture was then pressure-molded at a molding speed of 5.0 m / min to form a positive electrode having a weight of 20 mg / cm. ２ Thereafter, the positive electrode composite layer side of the prepared positive electrode raw sheet was roll-pressed in an environment at a temperature of 25±3°C, and the density of the positive electrode composite layer was adjusted to 3.50 g / cm. ３ A positive electrode of 1000 .mu.m was obtained.

[0158] (1-5. Preparation of Negative Electrode) 97.4 parts of natural graphite (volume-based median diameter: 22 μm, theoretical capacity: 360 mAh / g) as a negative electrode active material and 1.0 parts (solids equivalent) of carboxymethylcellulose ammonium salt (Daicel FineChem Co., Ltd., product number "DN-800H") were added to a planetary mixer. The contents of the mixer were diluted with ion-exchanged water to a solids concentration of 60%, and then kneaded for 60 minutes at a rotation speed of 45 rpm. Then, 1.5 parts (solids equivalent) of particulate polymer II as a binder II for the electrode mixture layer were added, and the contents of the mixer were kneaded for 40 minutes at a rotation speed of 40 rpm. Then, ion-exchanged water was added so that the viscosity (using a B-type viscometer, temperature: 25°C, rotor rotation speed: 60 rpm) was 3000±200 mPa·s, thereby preparing a negative electrode slurry composition. The obtained negative electrode slurry composition was applied to a copper foil having a thickness of 10 μm as a current collector using a comma coater in an amount of 10.5±0.5 mg / cm ２ The negative electrode blank was then conveyed at a speed of 0.2 m / min through an oven at 120°C for 2 minutes, and then through an oven at 130°C for 2 minutes to dry the slurry composition on the copper foil, thereby obtaining a negative electrode blank having a negative electrode composite layer formed on the current collector. Thereafter, the negative electrode composite layer side of the prepared negative electrode blank was roll-pressed in an environment at a temperature of 25±3°C, and the density of the negative electrode composite layer was adjusted to 1.60 g / cm. ３A negative electrode of 1000 .mu.m was obtained.

[0159] (1-6. Preparation of Separator) A single-layer polypropylene separator (manufactured by Celgard Co., Ltd., product name "Celgard 2500") was prepared as a separator made of a separator substrate.

[0160] (1-7. Preparation of Lithium-ion Secondary Battery) A laminated cell (equivalent to an initial design discharge capacity of 40 mAh) was prepared using the positive electrode obtained in (1-4), the negative electrode obtained in (1-5), and the separator prepared in (1-6), and placed in an aluminum package and vacuum dried at 60°C for 10 hours. Then, a 1.0M concentration of LiPF6 was added as an electrolyte. ６ A solution (solvent: a mixed solvent of ethylene carbonate (EC) / diethyl carbonate (DEC) = 3 / 7 (volume ratio), additive: containing 2 volume % vinylene carbonate (solvent ratio)) was filled. Furthermore, in order to seal the opening of the aluminum packaging, the aluminum packaging was closed by heat sealing at a temperature of 150°C, and a lithium ion secondary battery was produced. Using this lithium ion secondary battery, the IV characteristics and high-temperature storage characteristics were evaluated as described above.

[0161] Example 2 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the first adhesive layer of the positive electrode was set to 2 μm.

[0162] Example 3 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the first adhesive layer of the positive electrode was set to 0.25 μm.

[0163] Example 4 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the second adhesive layer of the positive electrode was set to 1 μm.

[0164] Example 5 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the second adhesive layer was set to 0.1 μm.

[0165] Example 6 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the second adhesive layer was set to 3 μm.

[0166] Example 7 An aqueous dispersion containing a second adhesive layer binder (glass transition temperature Tg: -40°C) with a volume-based median diameter of 0.3 µm was obtained by the same method as in Production Example 4, except that the amount of sodium dodecylbenzenesulfonate used as an emulsifier was changed to 0.5 parts. A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that this aqueous dispersion of the second adhesive layer binder was used instead of the second adhesive layer binder I obtained in Production Example 4.

[0167] Example 8 An aqueous dispersion containing a second adhesive layer binder (glass transition temperature Tg: -40°C) with a volume-based median diameter of 0.08 µm was obtained by the same method as in Production Example 4, except that the amount of sodium dodecylbenzenesulfonate used as an emulsifier was changed to 1.5 parts. A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that this aqueous dispersion of the second adhesive layer binder was used instead of the second adhesive layer binder I obtained in Production Example 4.

[0168] [Example 9] A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1, except that the ratio (%) of the width S2 of the region where the second adhesive layer coating liquid was applied to the width S1 of the region where the first adhesive layer coating liquid was applied was set to 105%. In this Example 9, the ratio of the area of ​​the first adhesive layer that was covered by the second adhesive layer to the total area of ​​the first adhesive layer was 40%.

[0169] [Example 10] A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1, except that the ratio (%) of the width S2 of the region where the second adhesive layer coating liquid was applied to the width S1 of the region where the first adhesive layer coating liquid was applied was set to 100%. In this Example 10, the ratio of the area of ​​the first adhesive layer that was covered by the second adhesive layer to the total area of ​​the first adhesive layer was 40%.

[0170] [Example 11] A lithium ion secondary battery was produced by the same procedures as in Example 1, except that the positive electrode and negative electrode were changed as follows. Using this lithium ion secondary battery, the IV characteristics and high-temperature storage characteristics were evaluated as described above.

[0171] (2-1. First Adhesive Layer) 5.0 parts of carboxymethyl cellulose (manufactured by Daicel Miraize Co., Ltd., "1220") and 2.5 parts of sodium salt of naphthalenesulfonic acid formalin condensate (manufactured by Kao Chemical Co., Ltd., "Demol N") were added to 300 parts of ion-exchanged water, and the mixture was stirred at 1500 rpm for 15 minutes using a disper. Then, 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") were added, and the mixture was stirred at 2000 rpm for 30 minutes using a disper. Furthermore, 27 parts of binder II for conductive adhesives (solids equivalent) were added, and the mixture was stirred at 1500 rpm for 15 minutes to obtain a coating liquid for the first adhesive layer. The obtained coating liquid for the first adhesive layer was applied to a copper current collector having a thickness of 10 μm and a width of 30 cm by a kiss reverse gravure method at a coating speed of 10 m / min and a drying temperature of 120° C. The obtained first adhesive layer had a film thickness of 0.5 μm, a coating width in the width direction of 25 cm, and a tacking strength of 0.02 N.

[0172] (2-2. Second adhesive layer) A coating liquid for a second adhesive layer was obtained by mixing the above-mentioned binder II for the second adhesive layer at 30% solids content and Dispanol TOC (manufactured by NOF Corporation), a nonionic surfactant, as a surfactant at 0.5%. The obtained coating liquid for a second adhesive layer was applied to the current collector on which the first adhesive layer was formed by a direct gravure method at a coating speed of 40 m / min and a drying temperature of 50°C. The obtained second adhesive layer had a film thickness of 0.3 μm, a coating width in the width direction of 25.5 cm, and a tacking strength of 1.7 N.

[0173] (2-3. Positive electrode) A planetary mixer was used as a positive electrode active material, and a Co—Ni—Mn lithium composite oxide active material NMC532 (LiNi ０．５ Co ０．２ Mn ０．３ O ２97 parts of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., product name "Li-400") as a conductive material, and 2 parts (solids equivalent) of polyvinylidene fluoride (manufactured by Kureha Corporation, product name "#7208") as a binder were added and mixed. Furthermore, N-methyl-2-pyrrolidone (NMP) as an organic solvent was gradually added, and the mixture was stirred and mixed at a temperature of 25±3°C and a rotation speed of 25 rpm to obtain a positive electrode slurry composition having a viscosity (using a Brookfield viscometer, temperature: 25±3°C, rotor: M4, rotor rotation speed: 60 rpm) of 3600 mPa·s. The obtained positive electrode slurry composition was applied to a 15 μm thick aluminum foil current collector using a comma coater in a coating amount of 20.0±0.5 mg / cm. ２ The slurry composition on the aluminum foil was then dried by transporting the aluminum foil at a speed of 0.2 m / min through an oven at 120°C for 2 minutes and then through an oven at 130°C for 2 minutes, thereby obtaining a positive electrode blank having a positive electrode composite layer formed on the current collector. Thereafter, the positive electrode composite layer side of the prepared positive electrode blank was roll-pressed in an environment at a temperature of 25±3°C, and the positive electrode composite layer density was adjusted to 3.50 g / cm. ３ A positive electrode of 1000 .mu.m was obtained.

[0174] (2-4. Composite Particles for Negative Electrode) 97.4 parts of natural graphite (volume-based median diameter: 22 μm, theoretical capacity: 360 mAh / g) as a negative electrode active material and 1.0 parts (solids equivalent) of carboxymethylcellulose ammonium salt (Daicel FineChem Co., Ltd., product number "DN-800H") were added to a planetary mixer. The contents of the mixer were diluted with ion-exchanged water to a solids concentration of 60%, and then kneaded for 60 minutes at a rotation speed of 45 rpm. Then, 1.5 parts (solids equivalent) of particulate polymer II as a binder II for the electrode mixture layer were added, and the contents of the mixer were kneaded for 40 minutes at a rotation speed of 40 rpm. Then, ion-exchanged water was added so that the viscosity (using a B-type viscometer, temperature: 25 ° C., rotor rotation speed: 60 rpm) was 1000 ± 200 mPa s, to prepare a negative electrode slurry composition. The obtained negative electrode slurry composition was supplied to a spray dryer (manufactured by Okawara Chemical Engineering Co., Ltd., product name "L-8i") and spray-dried using a rotating disk type Sharpedge atomizer (manufactured by Okawara Chemical Engineering Co., Ltd., diameter 65 mm) under conditions of 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 negative electrode composite particles having a volume-based median diameter of 70 μm.

[0175] (2-5. Negative Electrode) The composite particles for the negative electrode obtained above were fed to a press roll (roll temperature 50°C, press line pressure 500 kN / m) of a roll press machine ("Press-Cut Rough Surface Hot Roll" manufactured by Hirano Giken Kogyo Co., Ltd.) using a quantitative feeder ("Nikka Spray K-V" manufactured by Nikka Corporation). The copper foil on which the first adhesive layer and the second adhesive layer were formed was inserted between the press rolls, and the composite particles supplied from the quantitative feeder were attached to the copper foil and pressure-molded at a molding speed of 5.0 m / min. This resulted in a negative electrode comprising copper foil as a current collector and a negative electrode composite layer formed on one side of the copper foil. The weight per unit area of ​​the negative electrode composite layer was 10.5 mg / cm ２ and the density is 1.60 g / cm ３ It was.

[0176] Example 12 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 11, except that 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 set to 3 μm.

[0177] Example 13 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 11, except that the thickness of the first adhesive layer of the negative electrode was set to 5 μm.

[0178] Example 14 An aqueous dispersion containing a second adhesive layer binder (glass transition temperature Tg: -40°C) with a volume-based median diameter of 0.85 µm was obtained by the same method as in Production Example 4, except that the amount of sodium dodecylbenzenesulfonate used as an emulsifier was changed to 0.15 parts. A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that this aqueous dispersion of the second adhesive layer binder was used instead of second adhesive layer binder I obtained in Production Example 4 and the thickness of the second adhesive layer was changed to 0.9 µm.

[0179] [Example 15] A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1, except that 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%.

[0180] [Example 16] A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1, except that 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%.

[0181] Comparative Example 1 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the thickness of the first adhesive layer of the positive electrode was set to 2.5 μm and no second adhesive layer was provided.

[0182] Comparative Example 2 A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1, except that the first adhesive layer of the positive electrode was not provided, that is, the second adhesive layer was provided directly on the current collector layer.

[0183] <Results> The results of the above-mentioned Examples and Comparative Examples are shown in the table below. In the table below, the abbreviations have the following meanings: NMC532: LiNi ０．５ Co ０．２ Mn ０．３ O ２SIS hydrogenation product: styrene-isoprene-styrene copolymer hydrogenation product used as polymer I CMC: carboxymethyl cellulose ammonium salt ACR1: acrylate polymer used as binder I for the first adhesive layer ACR2: acrylate polymer used as binder I for the second adhesive layer SBR1: styrene-butadiene copolymer used as particulate polymer II SBR2: styrene-butadiene copolymer used as binder for the second adhesive layer Particle size D50: median diameter of composite particle or polymer Tg1 (°C): glass transition temperature of binder contained in the first adhesive layer Tg2 (°C): glass transition temperature of binder contained in the second adhesive layer Coverage (%): ratio of area of ​​the first adhesive layer covered by the second adhesive layer to the total area of ​​the first adhesive layer Tackiness ratio (second conductive layer / first conductive layer): ratio of tackiness value of the second conductive layer to the tackiness value of the first conductive layer

[0184]

[0185]

[0186]

[0187]

[0188]

[0189]

[0190] As shown in Examples 1 to 13 and Examples 14 to 16, it was confirmed that an electrode having a conductive adhesive layer with a first adhesive layer and a second adhesive layer can achieve both reduced I-V resistance and high-speed formability. On the other hand, as shown in Comparative Example 1, when only the first adhesive layer is provided, it is possible to reduce the I-V resistance but sufficient high-speed formability is not obtained. As shown in Comparative Example 2, when only the second adhesive layer is provided, it is confirmed that good high-speed formability is obtained but the I-V resistance is high. Furthermore, it was confirmed that lithium-ion batteries using the electrodes shown in Examples 1 to 13 and Examples 14 to 16 have improved high-temperature storage stability.

[0191] 1: current collector layer 2: conductive adhesive layer 3: electrode mixture layer 21: first adhesive layer 22: second adhesive layer

Claims

1. An electrode for a non-aqueous secondary battery comprising, in this order, a current collector layer, a conductive adhesive layer, and an electrode mixture layer, wherein the electrode mixture layer contains an electrode active material and a binder, and the conductive adhesive layer has 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 mixture layer, wherein the first adhesive layer contains conductive particles and a binder, and the second adhesive layer contains conductive particles and a binder and has a lower content of conductive particles than the first adhesive layer, or the second adhesive layer contains a binder and does not contain conductive particles.

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

3. The electrode for a non-aqueous secondary battery according to claim 1, wherein the second adhesive layer contains a binder 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 provided on a partial area 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 provided on the surface of the collector layer on the side on which the first adhesive layer is provided.

6. An electrode for a non-aqueous secondary battery as described in claim 1, wherein 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 is 20% or more and 80% or less.

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

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

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. An electrode for a non-aqueous secondary battery as described in claim 1, wherein the binder contained in the second adhesive layer is particulate and has a median diameter of 0.01 μm or more and 1 μm or less.

11. The electrode for a nonaqueous secondary battery according to claim 1, wherein the binder contained in the first adhesive layer has a glass transition temperature Tg1 of -30°C or higher and 25°C or lower, the binder contained in the second adhesive layer has a glass transition temperature Tg2 of -50°C or higher and -10°C or lower, and the Tg1 is higher than the Tg2.

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

13. A non-aqueous secondary battery comprising 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 according to claim 1 or 2.

14. A method for producing an electrode for a non-aqueous secondary battery as described in claim 1, comprising: a step (A) of providing the conductive adhesive layer on the current collector layer by carrying out a step (A1) of providing the first adhesive layer on a current collector layer; and a step (A2) of partially providing the second adhesive layer on the first adhesive layer; and a step (B) of supplying composite particles containing an electrode active material and a binder onto the second adhesive layer of the conductive adhesive layer, and applying pressure to provide an electrode mixture layer.

15. The method for producing an electrode for a non-aqueous secondary battery according to claim 14, wherein the current collector layer is long, and a width S1 of a region on the current collector layer where the first adhesive layer is provided and a width S2 of a region on the current collector layer where the second adhesive layer is provided satisfy the relationship represented by the following formula (1): 100≦S2 / S1×100≦110 (1)

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