Method for producing electrode body for nonaqueous electrolyte secondary battery, electrode body, and battery

Abstract

The present disclosure relates to a method for manufacturing an electrode body for an aqueous electrolyte secondary battery, comprising a pressing step of pressing a laminate comprising a positive electrode plate, a negative electrode plate, and a separator provided with a base material and an adhesive layer containing an adhesive resin on at least one side of the base material, the electrode body for a nonaqueous electrolyte secondary battery is obtained by pressing the adhesive resin at a temperature equal to or lower than the glass transition temperature of the adhesive resin and at a pressure of 8-20 MPa, and the area ratio of the adhesive layer to the base material in a plan view of the separator is 10-70%.

Description

Technical Field

[0001] The present invention relates to a method for producing an electrode body for a nonaqueous electrolyte secondary battery, and further relates to an electrode body for a nonaqueous electrolyte secondary battery and a nonaqueous electrolyte secondary battery including the electrode body. Background Art

[0002] Japanese Patent Application Laid-Open No. 2011-54502 discloses a lithium ion secondary battery including a separator and at least one of a positive electrode and a negative electrode integrated with an adhesive resin, wherein the adhesive resin exhibiting adhesiveness by heating is present on at least one surface of a base material of the separator. Summary of the invention

[0003] In Japanese Patent Publication No. 2011-54502, since hot pressing is performed at a relatively high temperature (temperature 60-120°C), the adhesion between the electrode plate and the separator is high, and the formability of the electrode body is improved, but the adhesion between the electrode plate and the separator becomes too high, and in the manufacturing process of the non-aqueous electrolyte secondary battery (hereinafter referred to as the battery), the impregnation of the non-aqueous electrolyte between the electrode plate and the separator is sometimes reduced. In addition, in the case where the substrate in the separator includes a porous film, since the laminate is pressed at a relatively high temperature, the voids in the porous film are flattened, and the impregnation of the non-aqueous electrolyte into the separator is sometimes reduced.

[0004] An object of the present disclosure is to provide an electrode body for a nonaqueous electrolyte secondary battery and a method for producing the same, which can achieve both good moldability of the electrode body and good injection and liquid containing properties of a nonaqueous electrolyte solution.

[0005] The present disclosure provides the following method for producing an electrode body for a nonaqueous electrolyte secondary battery (hereinafter, also referred to as an electrode body), an electrode body, and a battery.

[0006] [1] A method for producing an electrode body for a non-aqueous electrolyte secondary battery, comprising the following steps:

[0007] A preparation step of preparing a positive electrode plate, a negative electrode plate, and a separator, wherein the separator comprises a substrate and an adhesive layer containing an adhesive resin on at least one side of the substrate;

[0008] a lamination step of placing the adhesive layer of the separator in contact with at least one of the positive electrode plate and the negative electrode plate to obtain a laminate including the positive electrode plate, the separator and the negative electrode plate;

[0009] A pressing step of pressing the laminate at a temperature below the glass transition temperature of the adhesive resin and a pressure of 8 to 20 MPa to obtain an electrode body for a non-aqueous electrolyte secondary battery;

[0010] In the plan view of the separator, an area ratio of the adhesive layer to the base material is 10 to 70%.

[0011] [2] The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to [1], wherein the substrate includes a porous film.

[0012] [3] The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to [1] or [2], wherein in the pressing step, the temperature at which the stack is pressed is 15 to 35°C.

[0013] [4] The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to any one of [1] to [3], wherein in the pressing step, the time for pressing the stack is 3 seconds or more and less than 30 seconds.

[0014] [5] The method for manufacturing an electrode body for a non-aqueous electrolyte secondary battery according to any one of [1] to [4], wherein the separator further comprises a heat-resistant layer, and in the lamination step, the separator is arranged so that the heat-resistant layer side faces the positive electrode plate.

[0015] [6] An electrode body for a non-aqueous electrolyte secondary battery, comprising a positive electrode plate, a separator and a negative electrode plate,

[0016] The separator comprises a substrate including a porous membrane and an adhesive layer including an adhesive resin on at least one side of the substrate.

[0017] In the plan view of the separator, the area ratio of the adhesive layer to the substrate is 10 to 70%.

[0018] At least one of the positive electrode plate and the negative electrode plate is arranged in contact with the adhesive layer.

[0019] The adhesion between the substrate and at least one of the positive electrode plate and the negative electrode plate disposed in contact with the adhesive layer is 0.2 to 5.0 kN / m.

[0020] In the porous film, the difference between the porosity of a portion facing both the positive electrode active material coating portion and the negative electrode active material coating portion and the porosity of a portion not facing at least one of the positive electrode active material coating portion and the negative electrode active material coating portion is 8.0% or less.

[0021] [7] The electrode body for a non-aqueous electrolyte secondary battery according to [6], wherein the adhesive resin has a glass transition temperature exceeding 35°C.

[0022] [8] The electrode body for a non-aqueous electrolyte secondary battery according to [6] or [7], wherein the separator further includes a heat-resistant layer, and the separator is arranged so that the heat-resistant layer side faces the positive electrode plate.

[0023] [9] A non-aqueous electrolyte secondary battery comprising the electrode body for a non-aqueous electrolyte secondary battery according to any one of [6] to [8].

[0024] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart showing a method for manufacturing an electrode body.

[0026] Figure 2 It is a schematic cross-sectional view showing an example of the layer structure of a laminate.

[0027] Figure 3 It is a schematic cross-sectional view showing an example of the layer structure of a cylindrical wound body of a laminated body.

[0028] Figure 4 It is a schematic cross-sectional view showing an example of the layer structure of the stacked body.

[0029] Figure 5 It is a schematic diagram showing an example of the structure of a wound electrode body.

[0030] Figure 6 It is a schematic diagram showing an example of the structure of a stacked electrode body.

[0031] Figure 7 It is a schematic diagram showing an example of the structure of a non-aqueous electrolyte secondary battery. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present disclosure with reference to the accompanying drawings, but the present invention is not limited to the following embodiments. In all the following drawings, in order to facilitate the understanding of each component, the scale is appropriately adjusted for display, and the scale of each component shown in the drawings is not necessarily consistent with the scale of the actual component.

[0033] It should be noted that, in this specification, unless otherwise specified, elements expressed in the singular also include plural forms. For example, "particle" is not only "one particle" but also "an aggregate of particles (powder, powder, particle group)".

[0034] <Method for producing electrode body for non-aqueous electrolyte secondary battery>

[0035] like Figure 1 As shown, the manufacturing method of the electrode body disclosed in the present invention includes a preparation step (A), a lamination step (B), and a pressing step (C). In the preparation step (A), a positive electrode plate, a negative electrode plate, and a separator are prepared. The following description applies to the positive electrode plate, the negative electrode plate, and the separator.

[0036] In the lamination step (B), the adhesive layer of the separator is placed in contact with at least one of the positive electrode plate and the negative electrode plate to obtain a laminated body including the positive electrode plate, the separator and the negative electrode plate. By placing the adhesive layer of the separator in contact with at least one of the positive electrode plate and the negative electrode plate, the adhesion between the separator and at least one of the positive electrode plate and the negative electrode plate is improved, which has a tendency to easily improve the formability of the electrode body.

[0037] In the laminating step (B), the positive electrode plate and the negative electrode plate can be separated by sandwiching at least a portion of the separator between the positive electrode plate and the negative electrode plate. Figure 2 An example of the layer structure of the laminate is shown. Figure 2 The stacked body 40 shown includes a positive electrode plate 10, a negative electrode plate 20 and a separator 30. At least a portion of the separator 30 is sandwiched between the positive electrode plate 10 and the negative electrode plate 20. The separator 30 separates the positive electrode plate 10 and the negative electrode plate 20. At least one of the positive electrode plate 10 and the negative electrode plate 20 is bonded to the separator 30. The separator 30 may also have an adhesive layer described later on one side or both sides. In the case where the separator 30 has an adhesive layer described later, the positive electrode plate 10 and the negative electrode plate 20 may be bonded to the separator 30 via the adhesive layer, respectively. The positive electrode plate, the negative electrode plate and the separator may all have a square planar shape in a top view, or may be in a strip shape. The top view of the positive electrode plate, the negative electrode plate and the separator refers to the top view from the thickness direction ( Figure 2 When observing in the D-axis direction).

[0038] like Figure 2 As shown, the laminate 40 may also include two separators 30. The laminate 40 may also include a single separator 30. For example, the positive electrode plate 10 may be sandwiched by two separators 30. For example, the negative electrode plate 20 may be sandwiched by two separators 30. The laminate 40 is formed by, for example, sequentially stacking the separator 30 (first separator), the negative electrode plate 20, the separator 30 (second separator), and the positive electrode plate 10.

[0039] When the electrode body is a wound type as described below, the stacked body 40 can be wound into a spiral shape. For example, by winding the stacked body around a cylindrical winding core, such as Figure 3 As shown, a cylindrical wound body 41 can be formed.

[0040] When the electrode body is a laminated type as described later, a plurality of laminates 40 may be laminated. By laminating a plurality of laminates 40, as Figure 4 As shown, a collective stack 42 may be formed.

[0041] In the pressing step (C), the stack is pressed at a temperature below the glass transition temperature of the adhesive resin and a pressure of 8 to 20 MPa to obtain an electrode body for a non-aqueous electrolyte secondary battery. By pressing the stack at a temperature and pressure within the above range, the adhesion between the electrode plate and the separator becomes moderate in the manufacturing process of the non-aqueous electrolyte secondary battery, and there is a tendency to easily improve the permeability of the non-aqueous electrolyte. In addition, when the substrate in the separator contains a porous membrane, the voids are not easily flattened, and the decrease in the permeability of the non-aqueous electrolyte into the separator is suppressed, which tends to easily improve the injection and liquid containing properties of the non-aqueous electrolyte. In this specification, the pressure in the pressing step (C) is the pressure (surface pressure) applied to the pressing surface of the stack.

[0042] The temperature for pressing the laminate may be, for example, 0 to 60° C., more preferably 10 to 40° C., and even more preferably 15 to 35° C. The time for pressing the laminate may be, for example, 1 second or more and less than 60 seconds, 3 to 30 seconds, and even more preferably 3 to 20 seconds.

[0043] When the electrode body is a wound type, the cylindrical wound body 41 is pressed in the radial direction to form Figure 5 When the electrode body is a laminated type, the above-mentioned assembled laminated body 42 can be pressed to form a flat electrode body 50. Figure 6 The stacked electrode body 50 is shown.

[0044] In the top view of the separator, the area ratio of the adhesive layer in the separator to the substrate (hereinafter also referred to as the adhesive layer area ratio) is 10 to 70%. By making the adhesive layer area ratio within the above range, the adhesion between the electrode plate and the separator becomes moderate, and there is a tendency to easily improve the injection and liquid containing properties of the non-aqueous electrolyte. From the perspective of the injection and liquid containing properties of the non-aqueous electrolyte, the adhesive layer area ratio is preferably 10 to 60%. The adhesive layer area ratio is obtained by the method described in the Example column described later.

[0045] The adhesive layer area ratio can be set to the above range by adjusting the type and number of coating arrangement patterns of the adhesive layer present on the substrate, for example. The coating arrangement pattern can be, for example, a pattern (striped pattern) in which positions where adhesive resin is formed and positions where it is not formed are alternately grooved, and a pattern (dot pattern) in which a plurality of adhesive resins are discontinuously formed into circles, etc. These coating arrangement patterns can be arranged regularly or randomly.

[0046] The positive electrode plate includes a positive electrode collector and a positive electrode active material layer. The positive electrode plate may include a positive electrode active material layer on one or both sides of the positive electrode collector. The positive electrode collector may be a sheet or foil made of a metal such as aluminum, nickel, titanium, stainless steel, etc., preferably aluminum foil. When aluminum foil is used as the positive electrode collector, its thickness may be, for example, 5 μm to 35 μm, preferably 7 μm to 20 μm.

[0047] The positive electrode active material layer contains a positive electrode active material. The positive electrode active material is not particularly limited, and one or more materials commonly used as positive electrode active materials for lithium ion secondary batteries can be used. For example, lithium composite oxides, lithium transition metal phosphate compounds (such as LiFePO 4 ) etc. Examples of lithium composite oxides include lithium nickel composite oxides, lithium cobalt composite oxides, lithium manganese composite oxides, lithium nickel manganese composite oxides (e.g., LiNi 0.5 Mn 1.5 O 4 ), lithium nickel manganese cobalt composite oxides (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 )wait.

[0048] The positive electrode active material may be positive electrode active material particles. The average particle size of the positive electrode active material particles is not particularly limited, but may be approximately 0.5 μm to 50 μm, and typically 1 μm to 20 μm.

[0049] The positive electrode active material layer may contain materials other than the positive electrode active material, such as a conductive material, a binder, etc. As a conductive material, for example, carbon black such as acetylene black (AB) and other carbon materials (such as graphite) may be preferably used. As a binder, for example, fluorine-based binders such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and rubber-based binders such as styrene-butadiene rubber (SBR) may be preferably used. In addition, the positive electrode active material layer may also contain materials other than the above (such as various additives, etc.) as long as the effects of the present disclosure are not impaired.

[0050] From the viewpoint of energy density, the content of the positive electrode active material in the positive electrode active material layer (that is, the ratio of the positive electrode active material to the total mass of the positive electrode active material layer) is preferably approximately 70% by mass or more. For example, it is more preferably 75% by mass to 99% by mass, and more preferably 80% by mass to 97% by mass. In addition, the content of the conductive material in the positive electrode active material layer is preferably, for example, 0.1% by mass to 20% by mass, and more preferably 1% by mass to 15% by mass. The content of the binder in the positive electrode active material layer is preferably, for example, 0.5% by mass to 15% by mass, and more preferably 1% by mass to 10% by mass. In addition, in the case of various additives such as thickeners, the content of the additive in the positive electrode active material layer is preferably, for example, 7% by mass or less, and more preferably 5% by mass or less.

[0051] The positive electrode plate can be produced, for example, by applying a positive electrode slurry containing a positive electrode active material, a binder and an arbitrary amount of a dispersion medium onto a positive electrode current collector, drying it and then compressing it. The positive electrode plate can be cut into a predetermined planar size according to the electrode specification.

[0052] The negative electrode plate comprises a negative electrode collector and a negative electrode active material layer. The negative electrode plate comprises a negative electrode active material layer on one or both sides of the negative electrode collector. As the negative electrode collector, for example, a sheet or foil formed of a metal with good conductivity, such as copper, nickel, titanium, stainless steel, etc. can be cited. As the negative electrode collector, copper foil is preferred. The size is not particularly limited and can be appropriately determined according to the battery design. When copper foil is used, its thickness can be, for example, 5μm to 35μm, preferably 7μm to 20μm.

[0053] The negative electrode active material layer contains a negative electrode active material. As the negative electrode active material, for example, carbon materials such as graphite, hard carbon, and soft carbon can be used. The graphite can be natural graphite, artificial graphite, or amorphous carbon-coated graphite in which graphite is coated with an amorphous carbon material.

[0054] The negative electrode active material may be negative electrode active material particles. The average particle size of the negative electrode active material particles is not particularly limited, and is, for example, 0.1 μm to 50 μm, preferably 1 μm to 25 μm, and more preferably 5 μm to 20 μm.

[0055] The negative electrode active material layer may contain components other than the negative electrode active material, such as a binder and a thickener. As a binder, for example, styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), etc. can be used. As a thickener, for example, carboxymethyl cellulose (CMC) can be used.

[0056] The thickness of the negative electrode active material layer is not particularly limited, for example, it can be 10 μm to 300 μm, preferably 20 μm to 200 μm. The content of the negative electrode active material in the negative electrode active material layer is preferably 90% by mass or more, more preferably 95% by mass to 99% by mass. The content of the binder in the negative electrode active material layer is preferably 0.1% by mass to 8% by mass, more preferably 0.5% by mass to 3% by mass. The content of the thickener in the negative electrode active material layer is preferably 0.3% by mass to 3% by mass, more preferably 0.5% by mass to 2% by mass.

[0057] The negative electrode plate can be produced, for example, by applying a negative electrode slurry containing a negative electrode active material, a binder and an arbitrary amount of a dispersion medium onto a negative electrode current collector, drying it and then compressing it. The negative electrode plate can be cut into a predetermined planar size according to the electrode specification.

[0058] The separator includes a substrate and an adhesive layer containing an adhesive resin on at least one side of the substrate. The separator is sandwiched between the positive electrode plate and the negative electrode plate to separate the positive electrode plate from the negative electrode plate. The separator is electrically insulating.

[0059] The substrate may include a porous film. For example, the substrate may be substantially composed of a porous film. The porous film may be a resin film. The resin film may contain, for example, polyolefins, etc. The resin film may contain, for example, at least one selected from polyethylene (PE) and polypropylene (PP). The substrate may have, for example, a single-layer structure. For example, the substrate may be substantially composed of a PE layer. The substrate may have, for example, a multilayer structure. For example, the substrate may be formed by sequentially stacking a PP layer, a PE layer, and a PP layer. The resin film may have, for example, a thickness of 3 to 50 μm, a thickness of 3 to 30 μm, or a thickness of 5 to 15 μm.

[0060] The separator has an adhesive layer on one or both sides of the substrate. The adhesive layer can bond at least one of the positive electrode plate and the negative electrode plate to the separator (substrate) by, for example, press molding. The adhesive layer contains an adhesive resin. The glass transition temperature of the adhesive resin can, for example, exceed 35°C, and can be above 40°C or above 50°C. The glass transition temperature of the adhesive resin can, for example, be below 70°C or below 60°C, or below 80°C. Examples of adhesive resins include resin particles such as fluorine-based resins, acrylic resins, polyurethane resins, ethylene vinyl acetate resins, and epoxy resins. Fluorine-based resins include, for example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), and the like.

[0061] The separator may further have a heat-resistant layer. The heat-resistant layer may have the function of suppressing the shrinkage of the separator due to the heat during battery charging and discharging. The heat-resistant layer may contain, for example, inorganic particles and a binder. The inorganic particles include, for example, ceramic particles such as alumina, boehmite, aluminum hydroxide, silica, titanium dioxide, etc. As a binder, a resin material such as the above can be appropriately used as a constituent material of the adhesive layer. In the heat-resistant layer, the mixing ratio (mass ratio) of the inorganic particles and the binder is preferably 98:2 to 50:50, and more preferably 95:5 to 70:30. The thickness of the heat-resistant layer may be, for example, 1 to 10 μm, or 1 to 5 μm. The heat-resistant layer may be arranged on one or both sides of the substrate. The heat-resistant layer is preferably arranged on the side of the separator opposite to the positive electrode plate. In the case where the separator has a heat-resistant layer, it may be arranged directly on the substrate or between the substrate and the adhesive layer.

[0062] <Electrode body for non-aqueous electrolyte secondary battery>

[0063] The electrode body of the present disclosure comprises a positive electrode plate, a separator and a negative electrode plate. The electrode body can be Figure 5 The electrode body can be a wound electrode body 50. Figure 6 The stacked electrode body 50 is shown. The above description is applicable to the positive electrode plate, the separator, and the negative electrode plate.

[0064] At least one of the positive electrode plate and the negative electrode plate is arranged in contact with the adhesive layer. The adhesion between the substrate and at least one of the positive electrode plate and the negative electrode plate in contact with the adhesive layer can be, for example, 0.2 to 5.0 kN / m. By making the adhesion within the above range, there is a tendency to easily achieve both the formability of the electrode body and the injection and liquid containing properties of the non-aqueous electrolyte. The adhesion can be measured according to the adhesion measurement method described in the embodiment column described later. From the viewpoint of the formability of the electrode body and the injection and liquid containing properties of the non-aqueous electrolyte, the adhesion is preferably 0.5 to 5.0 kN / m.

[0065] In the case where the substrate includes a porous membrane, the difference between the porosity of the portion of the porous membrane that is opposite to both the positive electrode active material coating portion and the negative electrode active material coating portion (also referred to as the electrode plate relative portion) and the porosity of the portion that is not opposite to at least one of the positive electrode active material coating portion and the negative electrode active material coating portion (also referred to as the electrode plate non-relative portion) (hereinafter also referred to as the reduced porosity) can be, for example, 8.0% or less. The reduced porosity is obtained according to the method described in the embodiment column described later. From the viewpoint of the injection and liquid containing properties of the non-aqueous electrolyte, the pore reduction rate is preferably 4.0% or less, more preferably 3.0% or less, for example, 1.5% or more.

[0066] <Non-aqueous electrolyte secondary battery>

[0067] Figure 71 is a schematic diagram showing an example of the configuration of the battery in the present embodiment. The battery 100 can be used in any application. The battery 100 can be used as a main power source or a power auxiliary power source in, for example, an electric vehicle. By connecting a plurality of batteries 100, a battery module or a battery pack can be formed. The battery 100 can have a rated capacity of, for example, 1 to 300 Ah.

[0068] The battery 100 includes an electrode body 50 and a non-aqueous electrolyte (not shown). Figure 1 As shown, the battery 100 may further include an outer casing 90. The outer casing 90 accommodates the electrode body 50 and the non-aqueous electrolyte. The outer casing 90 is square (flat rectangular). The outer casing 90 may also be made of, for example, an aluminum (Al) alloy. The electrode body 50 may be Figure 7 The outer casing 90 is housed in a state where it is under pressure in the D-axis direction.

[0069] The outer casing 90 may include, for example, a sealing plate 91 and an outer can 92. The sealing plate 91 seals the opening of the outer can 92. The sealing plate 91 and the outer can 92 may be joined by, for example, laser processing. It should be noted that the outer casing 90 may have any form. The outer casing 90 may be, for example, in the shape of a bag. That is, the outer casing 90 may be a bag made of an Al laminated film, or the like.

[0070] A positive terminal 81 and a negative terminal 82 are provided on the sealing plate 91. The sealing plate 91 may be further provided with an injection port (not shown), an exhaust valve (not shown), etc. The non-aqueous electrolyte can be injected into the interior of the outer casing 90 from the injection port. The injection port can be closed by, for example, a sealing plug. The positive electrode collector component 71 connects the positive terminal 81 to the electrode body 50. The positive electrode collector component 71 may be, for example, an Al plate. The negative electrode collector component 72 connects the negative terminal 82 to the electrode body 50. The negative electrode collector component 72 may be, for example, a copper (Cu) plate.

[0071] The non-aqueous electrolyte typically uses a liquid substance in which an electrolyte salt (in other words, a supporting salt) is dissolved or dispersed in a non-aqueous solvent. As a non-aqueous solvent, various organic solvents such as carbonates, ethers, esters, nitriles, sulfones, and lactones used in the electrolyte of a general lithium-ion secondary battery can be used without particular limitation. Among them, carbonates are preferred, and as specific examples thereof, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), monofluoroethylene carbonate (MFEC), difluoroethylene carbonate (DFEC), monofluoromethyl difluoromethyl carbonate (F-DMC), dimethyl trifluorocarbonate (TFDMC), etc. Such a non-aqueous solvent can be used alone or in combination of two or more.

[0072] As the electrolyte salt, for example, LiPF 6 , LiBF 4 , lithium bis(fluorosulfonyl)imide (LiFSI) and other lithium salts, among which LiPF 6 . The concentration of the electrolyte salt is not particularly limited, but is preferably 0.7 mol / L to 1.3 mol / L. It should be noted that the non-aqueous electrolyte may also contain components other than the above components, such as film forming agents such as oxalate complexes, gas generating agents such as biphenyl (BP) and cyclohexylbenzene (CHB), thickeners and other additives, as long as the effects of the present disclosure are not significantly impaired.

[0073] Example

[0074] Hereinafter, the present disclosure will be described in further detail with reference to Examples. "%" and "parts" in the Examples are mass % and mass parts unless otherwise specified.

[0075] [Isolator]

[0076] A separator having a heat-resistant layer on one side of a PE film and adhesive layers containing an adhesive resin (glass transition temperature of 35° C. or higher) on both sides thereof was prepared.

[0077] [Measurement method of adhesion]

[0078] The electrode bodies prepared in the examples and comparative examples were cut into a size of 2 cm × 7 cm. The adhesion between the substrate and the positive electrode plate was measured by the method according to JIS K6854-1 under the condition of a tensile speed of 50 mm / min. When the adhesion was 0.2 kN / m or more, the adhesion between the separator and the electrode plate was fully ensured, and it was judged that the formability of the electrode body was good.

[0079] [Evaluation method of adhesive layer area ratio]

[0080] Disassemble the electrode bodies prepared in the examples and comparative examples and separate the separators. Then, place the separator on the microscope stage with the side to be calculated for the adhesive coverage facing up, and observe at a magnification of 10 to 200 times. At this time, if there is an adhesive coating arrangement pattern, adjust the magnification so that at least one cycle can be observed. By binarization processing, only the adhesive coating position in the observation range can be identified, thereby calculating the adhesive layer area ratio.

[0081] [Evaluation method of non-aqueous electrolyte impregnation]

[0082] The end of the electrode body prepared in the embodiment and the comparative example was immersed in the non-aqueous electrolyte placed in the tank and taken out after 6 hours. Then, the electrode body for evaluation of impregnation was disassembled, and the height of the non-aqueous electrolyte penetrating from the end of the impregnation side was measured, and the impregnation of the non-aqueous electrolyte was evaluated according to the following criteria.

[0083] A: The height of non-aqueous electrolyte penetration is more than 9 cm

[0084] B: The height of the non-aqueous electrolyte penetration is 6 cm or more and less than 9 cm

[0085] C: The height of the non-aqueous electrolyte penetration is 3 cm or more and less than 6 cm

[0086] D: The height of non-aqueous electrolyte penetration is less than 3cm

[0087] [Evaluation method for reducing porosity]

[0088] The electrode bodies prepared in the examples and comparative examples are disassembled, and the separators are taken out. The true density ρt of the electrode plate relative portion and the electrode plate non-relative portion of the substrate in the separator is determined by the gas replacement method. He is used as the gas. The apparent density ρ calculated based on the thickness, area and type of the separator is used to calculate the porosity of the electrode plate relative portion and the electrode plate non-relative portion of the substrate according to the formula: (1-ρ / ρt)×100. The pore reduction rate is calculated according to the formula: (1-porosity of the electrode plate relative portion / porosity of the electrode plate non-relative portion)×100. When the pore reduction rate is 8.0% or less, the pores will not be flattened due to pressing, and it is judged that the injection and liquid containing properties of the non-aqueous electrolyte are good.

[0089] <Example 1>

[0090] The positive electrode plate and the negative electrode plate were stacked via a separator to produce a laminate. The laminate was pressed at a pressing temperature of 25°C, a pressing pressure of 10 MPa, and a pressing time of 3 seconds to produce an electrode body. The obtained electrode body was evaluated for the adhesion between the electrode plate and the separator, the bonding layer area ratio, the impregnation speed, and the reduction of the porosity. The results are shown in Table 1.

[0091] <Examples 2 to 8 and Comparative Examples 1 to 8>

[0092] In Example 1, an electrode body was produced in the same manner as in Example 1 except that the pressing temperature, pressing pressure, and pressing time were set to the values ​​shown in Table 1 and the adhesive layer was formed on the separator to have the adhesive surface coverage rate shown in Table 1. The results are shown in Table 1.

[0093] Table 1

[0094]

[0095] As shown in Table 1, in Examples 1 to 8 according to the present disclosure, sufficient adhesion and non-aqueous electrolyte infiltration speed were ensured, and the electrode body with a small porosity was reduced. Therefore, it can be understood that according to the present disclosure, an electrode body for a non-aqueous electrolyte secondary battery and a method for manufacturing the same can be provided, which can take into account both the formability of the electrode body and the liquid injection and liquid containing properties of the electrolyte.

[0096] Although the embodiments of the present disclosure have been described, the embodiments of the present disclosure should be considered to be illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims, and is intended to include all modifications within the scope and meanings equivalent to the claims.

Claims

1. A method for manufacturing an electrode body for a non-aqueous electrolyte secondary battery, comprising the following steps: A preparation step of preparing a positive electrode plate, a negative electrode plate, and a separator, wherein the separator comprises a substrate and an adhesive layer containing an adhesive resin on at least one side of the substrate; A lamination step of placing the adhesive layer of the separator in contact with at least one of the positive electrode plate and the negative electrode plate to obtain a laminate including the positive electrode plate, the separator and the negative electrode plate; A pressing step of pressing the laminate at a temperature below the glass transition temperature of the adhesive resin and a pressure of 8 to 20 MPa to obtain an electrode body for a non-aqueous electrolyte secondary battery; In a plan view of the separator, an area ratio of the adhesive layer to the base material is 10 to 70%.

2. The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to claim 1, wherein: The substrate comprises a porous membrane.

3. The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to claim 1, wherein: In the pressing step, the temperature at which the laminate is pressed is 15 to 35°C.

4. The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to claim 1, wherein: In the pressing step, the time for pressing the laminate is 3 seconds or more and less than 30 seconds.

5. The method for producing an electrode body for a non-aqueous electrolyte secondary battery according to claim 1, wherein: The separator further includes a heat-resistant layer, and in the lamination step, the separator is arranged so that the heat-resistant layer side faces the positive electrode plate.

6. An electrode body for a non-aqueous electrolyte secondary battery, comprising a positive electrode plate, a separator and a negative electrode plate, The separator comprises a substrate including a porous membrane and an adhesive layer including an adhesive resin on at least one side of the substrate. In the top view of the separator, the area ratio of the adhesive layer to the substrate is 10 to 70%. At least one of the positive electrode plate and the negative electrode plate is arranged in contact with the adhesive layer, The adhesion force between the substrate and at least one of the positive electrode plate and the negative electrode plate disposed in contact with the adhesive layer is 0.2 to 5.0 kN / m. In the porous film, a difference between a porosity of a portion facing both the positive electrode active material coating portion and the negative electrode active material coating portion and a porosity of a portion not facing at least one of the positive electrode active material coating portion and the negative electrode active material coating portion is 8.0% or less.

7. The electrode body for a non-aqueous electrolyte secondary battery according to claim 6, wherein: The adhesive resin has a glass transition temperature exceeding 35°C.

8. The electrode body for a non-aqueous electrolyte secondary battery according to claim 6, wherein The separator further includes a heat-resistant layer, and the separator is arranged so that the heat-resistant layer side faces the positive electrode plate. 9 . A non-aqueous electrolyte secondary battery comprising the electrode body for a non-aqueous electrolyte secondary battery according to claim 6 .

Images