Liquid composition for forming insulating layer, storage container, electrode, electrode manufacturing apparatus, electrode manufacturing method, and electricity storage device

Abstract

To provide a liquid composition for forming an insulating layer that is excellent in discharge property, continuous discharge property, and redispersibility, and that can provide an insulating layer with excellent strength.SOLUTION: A liquid composition for forming an insulating layer contains: insulating inorganic particles; a dispersant having a carboxyl group or an acid anhydride group; and a binder. The binder has a weight-average molecular weight of 25,000 or more and 80,000 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid composition for forming an insulating layer, a container, an electrode, and a method for manufacturing the same. ,electrode Manufacturing equipment, A method for manufacturing an electrode, and This relates to an electricity storage device. [Background technology]

[0002] BACKGROUND ART Conventionally, in electricity storage devices such as lithium ion secondary batteries, electric double layer capacitors, lithium ion capacitors, and redox capacitors, paper, nonwoven fabric, porous film, and the like have been used as separators for the purpose of preventing short-circuiting between the positive electrode and the negative electrode. If the separator melts or shrinks due to overheating, an internal short circuit may occur. The instantaneous heat of the short circuit reaction causes the separator to shrink further. This causes the short circuit to expand, accelerating abnormal heating and potentially causing the battery to go into thermal runaway and catch fire. To prevent this short circuit reaction, a technology has been proposed that provides an insulating layer in areas prone to internal short circuits.

[0003] For example, in order to suppress an increase in battery temperature after an internal short circuit due to the inclusion of foreign matter, a nonaqueous electrolyte secondary battery has been proposed that has a protective layer that covers the boundary between the exposed portion of the current collector (where no active material layer is formed) and the active material layer, and the protective layer contains a curable resin and inorganic particles (see, for example, Patent Document 1). Furthermore, electrochemical elements or electrodes have been proposed that include an insulating layer containing a compound having a terminal hydroxyl group as a binder or a compound having a carboxyl group as a dispersant, with the aim of improving the strength of the insulating layer, maintaining battery characteristics, and achieving good stability (see, for example, Patent Documents 2 and 3). Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a liquid composition for forming an insulating layer that is excellent in ejectability, continuous ejectability, and redispersibility, and that can provide an insulating layer with excellent strength. [Means for solving the problem]

[0005] The liquid composition for forming an insulating layer of the present invention as a means for solving the above problems comprises: insulating inorganic particles; a dispersant having a carboxyl group or an acid anhydride group; A liquid composition for forming an insulating layer, comprising: The weight average molecular weight of the binder is 25,000 or more and 80,000 or less. the law of nature, The content of the binder is 1% by mass or more and 5% by mass or less with respect to the total amount of insulating inorganic particles in the insulating layer, The binder has a fluoroethylene group and a vinyl ether group. . [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a liquid composition for forming an insulating layer that is excellent in ejectability, continuous ejectability, and redispersibility, and that can provide an insulating layer that is excellent in strength. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing an electrode according to one embodiment of the present invention. [Figure 2A] FIG. 4 is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 2B] FIG. 4 is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 3A] FIG. 4 is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 3B] FIG. 4 is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 4] 1 is a schematic diagram showing an electrode manufacturing apparatus according to an embodiment of the present invention. [Figure 5] 1 is a schematic diagram showing an electrochemical device according to one embodiment of the present invention. [Figure 6] 1 is a schematic diagram illustrating an electricity storage device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Inkjet printing is preferred as a means for applying a liquid composition for forming an insulating layer in a thin, uniform manner with good positional accuracy to an active material layer and a substrate formed by a roll-to-roll production process, such as the nonaqueous electrolyte secondary battery described in Patent Document 1. Inkjet printing can apply the liquid composition for forming an insulating layer to an appropriate position while detecting the boundary between the exposed portion of the current collector and the active material layer by controlling the ON / OFF of each nozzle, and can also control the coating amount by adjusting the amount of droplets ejected from each nozzle hole. Generally, a liquid composition for forming an insulating layer is obtained by uniformly dispersing solid components (inorganic particles, binder, and dispersant) in a solvent. Conventionally (including the invention described in Patent Document 1), polymeric fluorine compounds such as polyvinylidene fluoride, curable resins, modified rubbers, and the like have been used as binders for liquid compositions for forming an insulating layer. However, these materials have high molecular weights, making it difficult to form droplets, and therefore unsuitable for inkjet ejection. Furthermore, even when a binder with a low molecular weight is used, the thixotropy tends to be high, making stable continuous ejection by inkjet difficult.

[0009] The electrochemical elements or electrodes described in Patent Documents 2 and 3 have a concern that the insulating layer does not have sufficient film strength when wound around a roll after drying in a roll-to-roll production process, and that some of the inorganic particles may peel off due to friction or the like that occurs during winding, and may become mixed into the electrolyte as impurities.

[0010] The insulating layer-forming liquid composition of the present invention can fully resolve various concerns in the prior art. More specifically, it is possible to realize a liquid composition for forming an insulating layer that is excellent in ejection properties and continuous ejection properties and that can provide an insulating layer with excellent strength. It is also possible to realize a liquid composition for forming an insulating layer that is excellent in redispersibility, which is a basic performance.

[0011] The present invention will be described in detail below.

[0012] (Liquid composition for forming insulating layer) The insulating layer-forming liquid composition of the present invention contains insulating inorganic particles, a dispersant having a carboxyl group or an acid anhydride group, and a binder, and may contain a solvent and other components as necessary.

[0013] In this specification, the "insulating layer-forming liquid composition" may be simply referred to as the "liquid composition." In this specification, the "dispersant having a carboxyl group or an acid anhydride group" may be simply referred to as the "dispersant". In this specification, the "binder" may be referred to as an "insulating layer-forming binder."

[0014] The insulating layer-forming liquid composition of the present invention has low thixotropy, and therefore has excellent ink-jet ejectability and continuous ejection properties, as well as excellent redispersibility after long-term storage. Furthermore, when the insulating layer-forming liquid composition is formed into a film, an insulating layer with excellent strength can be obtained, and the insulating layer does not peel off even when used as a battery that is repeatedly charged and discharged.

[0015] <Insulating inorganic particles> In this specification, "insulating" means a material having a volume resistivity of 10 8 That is, the insulating inorganic particles in the present invention have a volume resistivity of 10 8 Refers to inorganic particles with a resistance of Ω·cm or more.

[0016] As insulating inorganic particles, the volume resistivity is 10 8 As long as the resistivity is Ω·cm or more, there are no particular limitations and the material can be appropriately selected depending on the purpose, and examples include aluminum oxide (alumina), boehmite, silica, aluminum nitride, silicon nitride, cordierite, sialicron, mullite, stearite, yttria, zirconia, silicon carbide, etc. Among these, inorganic oxides are preferred, aluminum oxide and boehmite are more preferred, and α-alumina is even more preferred.

[0017] Alpha-alumina is known to function as a scavenger for "junk" species, i.e., species that can cause capacity fade in lithium-ion secondary batteries. Furthermore, alumina particles have good wettability and affinity for electrolytes, improving the cycling performance of lithium-ion secondary batteries. The use of alpha-alumina as insulating inorganic particles improves redispersibility and inkjet ejectability in liquid compositions and improves heat resistance in insulating layers. These insulating inorganic particles may be used alone or in combination of two or more kinds.

[0018] The shape of the insulating inorganic particles is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include rectangular, spherical, elliptical, cylindrical, oval, dogbone, amorphous, etc. Among these, from the viewpoint of improving ejection properties by inkjet, it is preferable that the insulating inorganic particles have a shape in which the aspect ratio of the long side to the short side is close to 1.

[0019] The median diameter of the insulating inorganic particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 200 nm or more and 1,000 nm or less. When the insulating inorganic particles have a median diameter of 200 nm or more, the particles can be prevented from floating in the air (generating mist) during inkjet ejection, and in the insulating layer, the insulating inorganic particles can be prevented from adhering to the substrate due to the loss of fine particles. When the median diameter of the insulating inorganic particles is 1,000 nm or less, nozzle clogging during inkjet ejection can be eliminated, improving ejection properties. In addition, in the case of an insulating layer, this is preferable because the thickness of the insulating layer is made uniform and homogenous (with less unevenness).

[0020] The method for measuring the median diameter of the insulating inorganic particles is not particularly limited and can be appropriately selected depending on the purpose. For example, the liquid composition can be diluted so that the solid content is 10 mass % or less, and then measured using a concentrated particle size analyzer (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.).

[0021] The insulating inorganic particles preferably include first insulating inorganic particles having a median diameter of 200 nm or more but less than 1,000 nm and second insulating inorganic particles having an average Stokes diameter of less than 30 nm. The average Stokes diameter refers to the average value of the long diameters of the particles measured, for example, by observation with a transmission electron microscope (TEM). When the liquid composition contains second insulating inorganic particles having an average Stokes diameter of less than 30 nm, the energy barrier in the interaction potential energy between particles can be made sufficiently small, and the problem of the insulating inorganic particles not being redispersed even when the liquid composition is stirred again when the insulating inorganic particles aggregate due to being left standing for a long period of time can be eliminated.

[0022] The content of the insulating inorganic particles is not particularly limited and can be selected appropriately depending on the purpose. However, from the viewpoint of making the thickness of the insulating layer uniform after drying, the content is preferably 20% by mass or more and 50% by mass or less, more preferably 25% by mass or more and 48% by mass or less, and even more preferably 35% by mass or more and 45% by mass or less, relative to the total amount of the liquid composition. When the content of the insulating inorganic particles is 20% by mass or more relative to the total amount of the liquid composition, it is possible to prevent the resulting insulating layer from bleeding onto the substrate and the electrode mixture layer. When the content of the insulating inorganic particles is 50% by mass or less based on the total amount of the liquid composition, nozzle clogging during inkjet ejection can be eliminated, ejection properties can be improved, and the insulating layer can be made uniform, which is also preferable.

[0023] The insulating inorganic particles may be appropriately synthesized or commercially available. Examples of commercially available aluminum oxide insulating inorganic particles include, by trade name, AKP-15, AKP-20, AKP-30, AKP-50, AKP-53, AKP-700, AKP-3000, AA-03, AA-04, AA-05, AA-07, AA-1.5, AKP-G07, and AKP-G15 (high-purity alumina manufactured by Sumitomo Chemical Co., Ltd.), TM-DA, TM-DAR, and TM-5D (manufactured by Taimei Chemical Industry Co., Ltd.), CT-3000LSSG (manufactured by Almatis), LS-502, LS-711CB, and SLS-710 (manufactured by Nippon Light Metal Co., Ltd.), and SEPal-60 and SEPal-70 (manufactured by Alteo).

[0024] <Dispersant having a carboxyl group or an acid anhydride group> The dispersant in the present invention has a carboxyl group or an acid anhydride group. Carboxyl groups have a repulsive effect between dispersant molecules due to steric hindrance. Therefore, by adding a dispersant having a carboxyl group to a liquid composition, insulating inorganic particles in the liquid composition can be uniformly dispersed as primary particles and maintained in a dispersed state without re-aggregation for a long period of time. Acid anhydride groups have excellent compatibility with binders for forming insulating layers, thereby reducing the thixotropy of the liquid composition. Furthermore, the carboxyl group or acid anhydride group can improve inkjet ejection properties due to their respective effects. Furthermore, the resulting insulating layer can eliminate problems such as a decrease in output due to an increase in battery resistance caused by the dissolution of the dispersant into the electrolyte and a decrease in cycle characteristics.

[0025] The dispersant having an acid anhydride group is not particularly limited and can be appropriately selected depending on the purpose. For example, a dispersant containing a structural unit represented by general formula (1) can be mentioned.

[0026] [ka] (In general formula (1), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.)

[0027] The dispersant having a carboxyl group is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a dispersant containing a structural unit represented by general formula (2) and a dispersant containing a structural unit represented by general formula (3).

[0028] [ka]

[0029] [ka] (In the general formulae (2) and (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.)

[0030] The number n in the general formula (1) is not particularly limited and can be appropriately selected depending on the purpose. There is no particular limitation on m in the general formula (2) and it can be appropriately selected depending on the purpose. There is no particular limitation on l in the general formula (3) and it can be appropriately selected depending on the purpose.

[0031] The method for determining whether a dispersant contains the structural units represented by general formulas (1) to (3) is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a nuclear magnetic resonance (NMR) device, Fourier transform infrared spectroscopy (FT-IR), etc. More specifically, it is possible to identify whether a dispersant contains each structural unit by scraping off an insulating layer, immersing the layer in a solvent such as tetrahydrofuran (THF), dissolving the resin component, and then analyzing the resulting layer.

[0032] The molecular weight of the dispersant is not particularly limited and can be appropriately selected depending on the purpose. For example, the number average molecular weight can be 1,000 or more and 100,000 or less. When the number average molecular weight of the dispersant is 1,000 or more, the insulating inorganic particles are excellently dispersed among themselves. When the number average molecular weight of the dispersant is 100,000 or less, excellent inkjet ejection properties are achieved. The method for analyzing the molecular weight of the dispersant is not particularly limited and can be appropriately selected depending on the purpose, but for example, it can be measured by gel permeation chromatography (GPC, manufactured by Shimadzu Corporation).

[0033] The content of the dispersant in the insulating layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0.5% by mass or more and 5% by mass or less, and more preferably 1% by mass or more and 3% by mass or less, of the total amount of insulating inorganic particles in the insulating layer. When the content of the dispersant is 0.5% by mass or more relative to the total amount of insulating inorganic particles in the insulating layer, the insulating inorganic particles can be sufficiently dispersed and maintained in a dispersed state. This improves inkjet ejection properties. Furthermore, the surfaces of the insulating inorganic particles are coated in the resulting insulating layer, preventing them from falling off the insulating layer. When the content of the dispersant is 5% by mass or less based on the total amount of insulating inorganic particles in the insulating layer, the thixotropy can be reduced, and the resulting insulating layer can be free from the problem of the dispersant eluting into the electrolyte and affecting battery performance.

[0034] The dispersant may be a suitably synthesized one or a commercially available one. Commercially available dispersants include, for example, Marialim (registered trademark) AAB-0851, Marialim AFB-1521, Marialim AKM-0531, Marialim AWS-0851, Marialim HKM-50A, Marialim SC-0708A, Marialim SC-0505K, and Marialim SC-1015F (all manufactured by NOF Corporation), SN Dispersant 5020, SN Dispersant 5040, SN Dispersant 5468, Nopcosperse 5600, and Nopcosant RFA (all manufactured by San Nopco Ltd.), SCONA (registered trademark) TSPP 10213GB, TSPP 22113GA, TSIN 4013 GC, and TSPOE 1002. Examples include GBLL, DISPER (registered trademark) BYK108, BYK-P105 (all manufactured by BYK-Chemie Co., Ltd.), ISOBAM (registered trademark)-04, ISOBAM-06, ISOBAM-10 (manufactured by Kuraray Co., Ltd.), and the like.

[0035] <Binder> The binder for forming the insulating layer in the present invention preferably has a fluoroethylene group and a vinyl ether group. When the binder for forming an insulating layer has a fluoroethylene group alone, its solubility in a solvent tends to be low and its thixotropy tends to be high. Furthermore, it is difficult to achieve a viscosity that can be ejected by inkjet. Even when the viscosity is reduced by lowering the solid content in the liquid composition, there are concerns that unevenness may occur after application to a substrate or the relative application amount of the liquid composition may increase. When the binder for forming an insulating layer in the present invention has a fluoroethylene group and a vinyl ether group, the solubility in general-purpose solvents such as alcohols and ethers is improved, and the thixotropy is accordingly reduced, making it possible to obtain a liquid composition that can be stably ejected by inkjet. Furthermore, in the obtained insulating layer, the battery stability can be improved by the binder for forming an insulating layer containing a fluoroethylene group. Thixotropy is a property in which the viscosity of a highly viscous fluid reversibly decreases when a force is applied to the fluid.

[0036] The method for confirming whether the binder for forming an insulating layer in the present invention has a fluoroethylene group and a vinyl ether group is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a nuclear magnetic resonance (NMR) device, Fourier transform infrared spectroscopy (FT-IR), etc. More specifically, the functional groups can be identified by scraping off the insulating layer, immersing it in a tetrahydrofuran (THF) solvent or the like, dissolving the resin component, and then analyzing it.

[0037] The weight average molecular weight (Mw) of the binder for forming the insulating layer in the present invention is 25,000 or more and 80,000 or less. When the weight-average molecular weight (Mw) of the binder for forming an insulating layer is 25,000 or more, the liquid composition can have a viscosity suitable for inkjet ejection, and an insulating layer having sufficient strength can be obtained. Furthermore, the obtained insulating layer is preferable because it does not dissolve in an electrolyte even in an oxidized state. When the weight average molecular weight (Mw) of the binder for forming the insulating layer is 80,000 or less, the thixotropy of the liquid composition is reduced, making it possible to stably eject the liquid composition by inkjet printing, and obtaining a uniform insulating layer.

[0038] The method for measuring the weight-average molecular weight (Mw) of the binder for forming an insulating layer is not particularly limited and can be appropriately selected depending on the purpose, and can be measured, for example, by gel permeation chromatography (GPC). More specifically, the weight-average molecular weight of the binder for forming an insulating layer can be measured by scraping off the insulating layer, immersing it in a solvent such as tetrahydrofuran (THF), dissolving the resin component, and then analyzing it.

[0039] The content of the binder for forming the insulating layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1% by mass or more and 5% by mass or less based on the total amount of insulating inorganic particles in the insulating layer. When the content of the binder for forming an insulating layer is 1 mass % or more based on the total amount of insulating inorganic particles in the insulating layer, an insulating layer having sufficient strength can be obtained. When the content of the insulating layer-forming binder is 5% by mass or less relative to the total amount of insulating inorganic particles in the insulating layer, thixotropy can be reduced, improving inkjet ejection properties and suppressing nozzle clogging and ejection abnormalities (curved ejection or abnormal ejection speed). The resulting insulating layer is preferable because it does not suffer from problems such as reduced output due to increased battery resistance and reduced cycle characteristics. More specifically, when the content of the insulating layer-forming binder is greater than 5% by mass, a portion of the insulating layer-forming binder may leach into the electrolyte, increasing battery resistance and reducing battery output. This may also accelerate the deterioration of battery performance in cycle evaluations.

[0040] The binder for forming the insulating layer may be an appropriately synthesized one or a commercially available product. Commercially available binders for forming insulating layers include, for example, Lumiflon (registered trademark) LF200F (manufactured by AGC Corporation), Zeffle (registered trademark) GK570 (manufactured by Daikin Corporation), Zafflon (registered trademark) GF-X-101, GF-400 (manufactured by Toa Gosei Co., Ltd.), and the like.

[0041] The dispersant and the binder for forming the insulating layer can be dissolved in a nonpolar solvent or a mixed solution containing a nonpolar solvent (mixed solvent). The solubility of the resin in a nonpolar solvent or a mixed solution containing a nonpolar solvent can be confirmed under conditions where the nonpolar solvent or the mixed solution containing a nonpolar solvent is liquid. For example, the solubility in a mixed solution containing a polar solvent such as ethylene carbonate in addition to dimethyl carbonate, ethyl methyl carbonate, and a nonpolar solvent, which are nonaqueous electrolyte solvents, can be confirmed at 25°C and 1 atmosphere. In this specification, a non-polar solvent is a solvent having a bond dipole moment of 1.15 D or less. The solubility of a resin in a non-polar solvent or a mixed liquid containing a non-polar solvent is preferable from the viewpoint of improving the thixotropy of the liquid composition.

[0042] Examples of binders for forming insulating layers that dissolve in non-polar solvents include Lumiflon (registered trademark) LF200F (manufactured by AGC Corporation), Zeffle (registered trademark) GK570 (manufactured by Daikin Corporation), Zafflon (registered trademark) GF-X-101, and GF-400 (manufactured by Toa Gosei Co., Ltd.). Examples of binders for forming insulating layers that are not soluble in non-polar solvents include KF Polymer (registered trademark) #850, W#1100, W#9100 (manufactured by Kureha Corporation), and Solef (registered trademark) 5130 (manufactured by Solvay Japan Co., Ltd.).

[0043] The ratio of the dispersant to the insulating layer-forming binder (dispersant:insulating layer-forming binder) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 3:1 to 3:15. If the ratio of the dispersant to the binder for forming the insulating layer is 3:1 or more, the resulting insulating layer does not dissolve in the electrolyte solution, which is preferable. When the ratio of the dispersant to the binder for forming the insulating layer is 3:15 or less, the ejection properties by inkjet are improved, and the occurrence of nozzle clogging and ejection abnormalities can be suppressed. Although the dispersant and the binder for forming the insulating layer can be dissolved alone in a non-polar solvent or a mixed solution containing a non-polar solvent, by combining the dispersant and the binder for forming the insulating layer in the above ratio, an insulating layer with excellent film strength after cycle testing can be formed.

[0044] <Solvent> The insulating layer-forming liquid composition of the present invention may contain a solvent. The solvent is not particularly limited as long as it can disperse the insulating inorganic particles, and can be appropriately selected depending on the purpose. Examples of the solvent include water, hydrocarbon solvents, alcohol solvents, ketone solvents, ester solvents, and ether solvents. Specific examples of the solvent include water, N-methyl-2-pyrrolidone, dimethyl sulfoxide, ethyl lactate, methyl ethyl ketone, 2-heptanone, diacetone alcohol, isopropyl alcohol, diisobutyl ketone, cyclohexanone, butyl acetate, isopropyl glycol, propylene glycol, ethylene glycol, hexylene glycol, 1-propoxy-2-propanol, 2-pyrrolidone, triethylene glycol, diethylene glycol, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. These solvents may be used alone or in combination of two or more.

[0045] The content of the solvent is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, 40% by mass or more and 70% by mass or less relative to the total amount of the liquid composition.

[0046] <Other ingredients> The liquid composition for forming an insulating layer of the present invention may contain, as other components, additives such as surfactants, pH adjusters, rust inhibitors, preservatives, antifungal agents, antioxidants, antireducing agents, evaporation promoters, and chelating agents. The content of other components is not particularly limited and can be set appropriately depending on the content of various components in the liquid composition.

[0047] [viscosity] The viscosity of the liquid composition for forming an insulating layer of the present invention is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of improving the ejection properties by inkjet, it is preferably 5.0 mPa·s or more and 30 mPa·s or less.

[0048] In the insulating layer-forming liquid composition of the present invention, when the viscosity measured using an E-type viscometer at 100 rpm is defined as viscosity A, and the viscosity measured using an E-type viscometer at 10 rpm is defined as viscosity B, it is preferable that the ratio of viscosity B to viscosity A [B / A] is 0.95 or more and 1.05 or less. A ratio of viscosity B to viscosity A [B / A] of 0.95 or more and 1.05 or less indicates that the liquid composition has low thixotropy. When the ratio of viscosity B to viscosity A [B / A] is 0.95 or more and 1.05 or less, ejection defects do not occur even in continuous inkjet ejection, and stable ejection is possible. In addition, problems such as nozzle clogging and ejection defects during continuous ejection due to ejection deflection or abnormal ejection speed can be eliminated.

[0049] The method for measuring the viscosity of the liquid composition for forming an insulating layer of the present invention is not particularly limited and can be selected appropriately depending on the purpose. For example, the viscosity can be measured using an E-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.) with a standard rotor of 1°34' x R24.

[0050] [surface tension] The surface tension of the liquid composition for forming an insulating layer of the present invention is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of improving ejection properties by inkjet, it is preferably 15 mN / m or more and 40 mN / m or less.

[0051] <Method of manufacturing liquid composition for forming insulating layer> The method for producing the insulating layer-forming liquid composition of the present invention is not particularly limited and can be appropriately selected depending on the purpose, and can be obtained, for example, by adding solvent B, in which an insulating layer-forming binder and other components are dissolved, to a dispersion in which insulating inorganic particles and a dispersant are dispersed in solvent A. Solvent A and solvent B may be the same solvent or different solvents. The dispersion may be prepared by pre-stirring the solvent, insulating inorganic particles, and dispersant in a dispersing machine. The dispersing machine is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a homomixer, a homogenizer, an ultrasonic dispersing machine, a ball mill, a bead mill, and a cavitation mill.

[0052] (electrode) The electrode of the present invention has a substrate, an electrode mixture layer provided on a portion of the substrate, and an insulating layer covering the boundary between the substrate exposed portion where the substrate is exposed and the electrode mixture layer, wherein the insulating layer contains insulating inorganic particles, a dispersant, and a binder, the dispersant contains at least one selected from the group consisting of a structural unit represented by general formula (1), a structural unit represented by general formula (2), and a structural unit represented by general formula (3), and the weight average molecular weight of the binder is 25,000 or more and 80,000 or less. The insulating layer in the electrode of the present invention is formed from the insulating layer-forming liquid composition of the present invention, and therefore, explanations that overlap with the section (insulating layer-forming liquid composition) in this specification will be omitted.

[0053] [ka]

[0054] [ka]

[0055] [ka] (In the general formulae (1) to (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.)

[0056] Here, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In each drawing, the same components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0057] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an electrode according to one embodiment of the present invention. The electrode 100 has a base 1, an electrode mixture layer 2 provided on a portion of the base 1, and an insulating layer 3. The insulating layer 3 is provided at the boundary between the electrode mixture layer 2 and a base exposed portion 11 where the base 1 is exposed. Although Figure 1 illustrates a configuration in which an electrode mixture layer 2 and an insulating layer 3 are provided on one side of the base 1, the electrode mixture layer 2 and the insulating resin layer 3 may be provided on both opposing sides of the base 1.

[0058] <Base> The substrate is not particularly limited as long as it has electron conductivity and is stable to an applied potential, and can be appropriately selected depending on the purpose. Examples include aluminum foil, copper foil, stainless steel foil, titanium foil, etched foil obtained by etching any of these to form fine holes, carbon-coated foil whose surface is coated with a carbon-containing resin layer, and perforated substrates used in lithium ion capacitors.

[0059] <Electrode composite layer> The electrode mixture layer is provided on a portion of the substrate. In other words, the electrode mixture layer is formed so as to leave an exposed portion of the substrate where no electrode mixture layer is provided, for the purpose of providing an insulating layer or welding a lead. The electrode mixture layer (sometimes referred to as "active material layer") is composed mainly of an active material (negative electrode active material or positive electrode active material). In this specification, "composed mainly of an active material" means that the content of the active material is 70 mass % or more of the entire electrode mixture layer.

[0060] The electrode mixture layer is not particularly limited and can be appropriately selected depending on the purpose. For example, it contains an active material (negative electrode active material or positive electrode active material), and may contain a conductive additive, a binder for the electrode mixture layer, a dispersant for the electrode mixture layer, a solid electrolyte, and other components as necessary.

[0061] [Figure 2A~Figure 2B] Here, Figure 2A is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention, and Figure 2B is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. The electrode mixture layer may have openings 21 as shown in FIG. 2A. The number of openings 21 is preferably one or more, and more preferably two or more. The opening 21 may penetrate the electrode mixture layer from the surface of the electrode mixture layer to the surface of the substrate, or may not penetrate all the way to the surface of the substrate. The opening 21 may be hollow or may be filled with the material 22. When the opening 21 is filled with the material 22, the material 22 may be a single type or a mixture of two or more types, but in either case, the material 22 is different from the material constituting the electrode mixture layer. From the viewpoint of improving ion conductivity, the material 22 is preferably a material having a solid electrolyte. The electrode mixture layer having the openings 21 can be suitably produced by using inkjet as the electrode mixture layer forming means, since application control is easy.

[0062] As shown in FIG. 2B, the electrode mixture layer may have an adhesive layer 23 between the substrate 1 and the electrode mixture layer 2, the adhesive layer 23 containing a metal that alloys with lithium. When an adhesive layer 23 is provided between the substrate 1 and the electrode mixture layer 2, the boundary between the adhesive layer 23 and the substrate exposed portion 11 is defined as the boundary in the present invention.

[0063] <<Active material>> The active material may be a positive electrode active material or a negative electrode active material. The positive electrode active material or the negative electrode active material may be used alone or in combination of two or more.

[0064] -Cathode active material- The positive electrode active material is not particularly limited as long as it is a material that can reversibly store and release alkali metal ions, and alkali metal-containing transition metal compounds can be used. Examples of alkali metal-containing transition metal compounds include lithium-containing transition metal compounds such as composite oxides containing lithium and one or more elements selected from the group consisting of cobalt, manganese, nickel, chromium, iron, and vanadium. Examples of lithium-containing transition metal compounds include lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide.

[0065] As the alkali metal-containing transition metal compound, a polyanionic compound having an XO4 tetrahedron (X=P, S, As, Mo, W, Si, etc.) in its crystal structure can be used. Among these, lithium-containing transition metal phosphate compounds such as lithium iron phosphate and lithium vanadium phosphate are preferred from the viewpoint of cycle characteristics, and lithium vanadium phosphate is more preferred from the viewpoint of lithium diffusion coefficient and output characteristics. When a polyanionic compound is used, it is preferable that the surface of the compound is coated with a conductive aid such as a carbon material to form a composite, in terms of electron conductivity.

[0066] The alkali metal-containing transition metal compound preferably has at least a portion of its surface coated with an ion-conductive oxide, preferably a lithium ion-conductive oxide. The lithium ion conductive oxide is not particularly limited and can be appropriately selected depending on the purpose. For example, x AO y(A is B, C, Al, Si, P, S, Ti, Zr, Nb, Mo, Ta, Sc, V, Y, Ca, Sr, Ba, Hf, Ta, Cr or W, and x and y are positive numbers). Specific examples of lithium ion conductive oxides include Li3BO3, LiBO2, Li2CO3, LiAlO2, Li4SiO4, Li2SiO3, Li3PO4, Li2SO4, Li2TiO3, and Li4Ti5O. 12 , Li2Ti2O5, Li2ZrO3, LiNbO3, LiTaO3, Li2MoO4, and Li2WO4. Among these, Li4Ti5O 12 , Li2ZrO3, or LiNbO3 are preferred. The lithium ion conductive oxide may be a composite oxide, which may be any combination of lithium ion conductive oxides, such as Li4SiO4-Li3BO3 and Li4SiO4-Li3PO4.

[0067] -Negative electrode active material- The negative electrode active material is not particularly limited as long as it is a material that can reversibly absorb and release alkali metal ions and can be appropriately selected depending on the purpose. For example, a carbon material containing graphite having a graphite-type crystal structure can be used. Examples of carbon materials include natural graphite, spherical or fibrous artificial graphite, non-graphitizable carbon (hard carbon), and easily graphitizable carbon (soft carbon). Examples of materials other than carbon materials include lithium titanate and titanium oxide. From the viewpoint of increasing the energy density of a lithium ion battery, high-capacity materials such as silicon, tin, silicon alloys, tin alloys, silicon oxide, silicon nitride, and tin oxide can also be suitably used as the negative electrode active material.

[0068] <<Conductive additives>> The conductive additive is not particularly limited and can be appropriately selected depending on the purpose. For example, carbon black produced by a furnace method, an acetylene method, a gasification method, or the like, or carbon materials such as carbon nanofibers, carbon nanotubes, graphene, and graphite particles can be used. Examples of the conductive additive other than the carbon material include metal particles such as aluminum, metal fibers, etc. The conductive additive may be previously compounded with the active material.

[0069] The content of the conductive additive relative to the active material is not particularly limited and can be set appropriately depending on the purpose, but is preferably 10% by mass or less, and more preferably 8% by mass or less. If the content of the conductive assistant relative to the active material is 10% by mass or less, the stability of the electrode mixture layer-forming liquid composition is improved, which is preferable. If the content of the conductive auxiliary agent relative to the active material is 8% by mass or less, the stability of the electrode mixture layer-forming liquid composition is further improved, which is preferable.

[0070] <<Binder for electrode mixture layer>> The electrode mixture layer binder is not particularly limited and can be appropriately selected depending on the purpose, as long as it can bind negative electrode materials together, positive electrode materials together, a negative electrode material and a negative electrode substrate, or a positive electrode material and a positive electrode substrate. When the electrode mixture layer-forming liquid composition is used for inkjet ejection, it is preferable that the electrode mixture layer binder is one that does not easily increase the viscosity of the electrode mixture layer-forming liquid composition, from the viewpoint of suppressing nozzle clogging of the liquid ejection head. In this specification, a distinction is made between the "binder" or "insulating layer binder" in the insulating layer-forming liquid composition and the "electrode mixture layer binder" in the electrode mixture layer-forming liquid composition.

[0071] As the binder for the electrode mixture layer, a polymer compound can be used. Examples of polymer compounds include thermoplastic resins such as polyvinylidene fluoride (PVDF), acrylic resin, polyethylene, polypropylene, polyurethane, nylon, polytetrafluoroethylene, polyphenylene sulfide, polyethylene terephthalate, and polybutylene terephthalate, polyamide compounds, polyimide compounds, polyamideimide, ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), nitrile butadiene rubber (NBR), isoprene rubber, polyisobutene, polyethylene glycol (PEO), polymethylmethacrylate (PMMA), and polyethylene vinyl acetate (PEVA).

[0072] The content of the binder for the electrode mixture layer relative to the active material is not particularly limited and can be set appropriately depending on the purpose, but is preferably 1% by mass or more and 15% by mass or less, and more preferably 3% by mass or more and 10% by mass or less. If the content of the binder for the electrode mixture layer relative to the active material is 1% by mass or more, the active material can be firmly bound to the base, which is preferable.

[0073] <<Dispersant for electrode mixture layer>> The dispersant for the electrode mixture layer is not particularly limited as long as it is capable of improving the dispersibility of the active material in the liquid composition for forming the electrode mixture layer. Examples include polymer dispersants such as polyethylene oxides, polypropylene oxides, polycarboxylic acids, naphthalenesulfonic acid formalin condensation, polyethylene glycols, polycarboxylic acid partial alkyl esters, polyethers, and polyalkylene polyamines; low molecular weight dispersants such as alkyl sulfonic acids, quaternary ammonium higher alcohol alkylene oxides, polyhydric alcohol esters, and alkyl polyamines; and inorganic dispersants such as polyphosphate dispersants. In this specification, a distinction is made between a "dispersant having a carboxyl group or an acid anhydride group" in the insulating layer-forming liquid composition and a "dispersant for an electrode mixture layer" in the electrode mixture layer-forming liquid composition.

[0074] <<Solid electrolyte>> The solid electrolyte is not particularly limited as long as it is a solid substance that has electronic insulation properties and exhibits ionic conductivity, but sulfide solid electrolytes and oxide solid electrolytes are preferred from the viewpoint of high ionic conductivity.

[0075] Examples of sulfide solid electrolytes include Li 10 GeP2S 12 and Li6PS5X (X=F, Cl, Br, I) which has an argyrodite-type crystal structure. As an oxide-based solid electrolyte, for example, LLZ (Li7La3Zr2O 12 ), LATP (Li1+xAlxTi) with NASICON-type crystal structure 20 x(PO4)3) (0.1≦x≦0.4), LLT(Li 0.33 La 0.55 TiO3), amorphous LIPON (Li 2.9 PO 3.3 N 0.4 ) etc. These solid electrolytes may be used alone or in combination of two or more.

[0076] When the electrode mixture layer is a positive electrode mixture layer, the average thickness of the positive electrode mixture layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm or more and 300 μm or less, and more preferably 40 μm or more and 150 μm or less. When the average thickness of the positive electrode mixture layer is 10 μm or more, the energy density of the electrochemical device is improved. When the average thickness of the negative electrode mixture layer is 300 μm or less, the load characteristics of the electrochemical device are improved.

[0077] When the electrode mixture layer is a negative electrode mixture layer, the average thickness of the negative electrode mixture layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm or more and 450 μm or less, and more preferably 20 μm or more and 100 μm or less. When the average thickness of the negative electrode mixture layer is 10 μm or more, the energy density of the electrochemical device is improved. When the average thickness of the negative electrode mixture layer is 450 μm or less, the cycle characteristics of the electrochemical device are improved.

[0078] The electrode mixture layer may be formed on both sides of the substrate (positive electrode substrate and / or negative electrode substrate). The electrodes may be stacked in multiple layers to increase the charge / discharge capacity of the electrodes. There is no particular limit to the number of positive electrodes or negative electrodes stacked, and the number can be increased as needed.

[0079] <Insulating layer> The insulating layer in the electrode of the present invention is provided so as to cover the boundary between the electrode mixture layer 2 and the substrate exposed portion 11 where the substrate is exposed.

[0080] [Figures 3A-3B] Here, Figure 3A is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention, and Figure 3B is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. 3A, the insulating layer 3 may be provided at the boundary portion and on the edge portion of the electrode mixture layer 2. As shown in FIG. 3B, the insulating layer 3 may be provided at the boundary portion and on the upper surface of the electrode mixture layer 2. When the insulating layer 3 is provided on the upper surface of the electrode mixture layer 2, the coverage of the upper surface of the electrode mixture layer 2 by the insulating layer 3 is preferably 90% or more, more preferably 95% or more, and even more preferably 100%. In other words, when the insulating layer 3 is provided on the upper surface of the electrode mixture layer 2, an exposed region that is not covered by the insulating layer 3 may exist on the upper surface of the electrode mixture layer 2. By providing the insulating layer 3 on the electrode mixture layer 2, when coating by inkjet, it is possible to form an insulating layer with a small thickness and uniformity, and the stability of the battery is improved.

[0081] The average thickness of the insulating layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2 μm or more and 20 μm or less, and more preferably 5 μm or more and 10 μm or less. If the average thickness of the insulating layer is 2 μm or more, sufficient insulating properties are obtained, which is preferable. When the average thickness of the insulating layer is 20 μm or less, problems such as the electrode mixture layer being damaged by the weight of the liquid composition itself when the liquid composition is applied, the liquid composition flowing and causing unevenness, or the liquid composition seeping into the substrate can be eliminated.

[0082] The method for measuring the average thickness of the insulating layer is not particularly limited and can be appropriately selected depending on the purpose. For example, the average thickness can be measured using a Digimatic Micrometer (manufactured by Mitutoyo Corporation).

[0083] The peel strength of the insulating layer from the substrate is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 50 N / m or more. When the peel strength of the insulating layer from the substrate is 50 N / m or more, it is possible to prevent some of the insulating inorganic particles contained in the insulating layer from falling off due to friction during transportation or when forming an electrode using a roll-to-roll method, and also to prevent the battery characteristics from being affected.

[0084] The method for measuring the peel strength of the insulating layer from the substrate is not particularly limited and can be appropriately selected depending on the purpose. An example is shown below. [Method for measuring peel strength] The evaluation device used is, for example, a light-load type adhesive / coating peeling analyzer (VPA-3S, manufactured by Kyowa Interface Science Co., Ltd.) and 8 mm wide tape (cellophane tape, manufactured by Nitto Co., Ltd.). The tape is attached to the insulating layer and peeled at a peel angle of 90 degrees and a speed of 30 mm / min. The load applied to the load cell is taken as the peel strength.

[0085] The width of the insulating layer is not particularly limited and can be appropriately selected depending on the battery configuration, but is preferably 2 mm or more and 30 mm or less. The "width" of the insulating layer refers to the distance (in the longitudinal direction of the electrode) from one end to the other end of the upper surface of the insulating layer facing the substrate surface in contact with the electrode composite layer in a cross-sectional view when the electrode is cut in the thickness direction of the electrode and in a direction parallel to the longitudinal direction of the electrode. If the width of the insulating layer is 2 mm or more, it is difficult for the insulating layer to follow the meandering of the electrode mixture layer, and the problem of the exposed portion of the substrate not being covered by the insulating layer can be resolved. If the width of the insulating layer is 30 mm or less, problems such as impediments to lead welding and battery size being too large for the battery capacity can be resolved.

[0086] The width of the insulating layer covering the electrode mixture layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 mm or more and 5 mm or less. In this specification, the term "cover width" refers to the distance (in the longitudinal direction of the electrode) from one end to the other end of the surface where the electrode mixture layer and the insulating layer contact, facing the substrate surface in contact with the electrode mixture layer, in a cross-sectional view when the electrode is cut in the thickness direction of the electrode and in a direction parallel to the longitudinal direction of the electrode. If the covering width is 0.1 mm or more, it is difficult to follow the meandering of the electrode mixture layer, and the problem of the exposed portion of the substrate not being covered with the insulating layer can be resolved. If the covering width is 5 mm or less, it is possible to prevent the insulating layer from adversely affecting the battery capacity.

[0087] The electrode mixture layer 2 and the insulating layer 3 may be bonded together with an adhesive. In other words, the electrode mixture layer 2 and the insulating layer 3 may be bonded together via an adhesive layer derived from an adhesive.

[0088] The adhesive is not particularly limited and can be appropriately selected depending on the purpose, but is preferably at least one selected from acrylate and PVDF (polyvinylidene fluoride).

[0089] The adhesive may be applied by an inkjet method, which allows the adhesive to be applied precisely in a desired shape.

[0090] (Electrode manufacturing equipment) The electrode manufacturing apparatus of the present invention has a container and a means for applying a liquid composition for forming an insulating layer, and may also have an electrode mixture layer forming means, a means for heating the liquid composition for forming an insulating layer, and other means, as necessary. The method for producing an electrode according to the present invention may include an electrode mixture layer forming step, an insulating layer forming step, and other steps.

[0091] <Containment Container> The storage container includes an insulating layer forming liquid composition and a container, and is a storage container in which the insulating layer forming liquid composition is stored. Examples of containers include glass bottles, plastic containers, plastic bottles, stainless steel bottles, 18L cans, drums, and the like.

[0092] <Electrode mixture layer forming step and electrode mixture layer forming means> The electrode mixture layer forming step is a step of forming an electrode mixture layer on a part of a substrate, and preferably includes an electrode mixture layer forming liquid composition applying step and an electrode mixture layer forming liquid composition heating step. The electrode mixture layer forming means is means for forming an electrode mixture layer on a part of the substrate, and preferably includes an electrode mixture layer forming liquid composition applying means and an electrode mixture layer forming liquid composition heating means. The electrode mixture layer forming step can be suitably carried out by an electrode mixture layer forming means.

[0093] <<Electrode mixture layer forming liquid composition applying step and electrode mixture layer forming liquid composition applying means>> The electrode mixture layer forming liquid composition applying step is a step of applying the electrode mixture layer forming liquid composition to a part of the substrate. The electrode mixture layer forming liquid composition applying means is a means for applying the electrode mixture layer forming liquid composition to a part of the substrate. The electrode mixture layer forming liquid composition applying step can be suitably carried out by an electrode mixture layer forming liquid composition applying means.

[0094] When producing a positive electrode, a liquid composition for forming an electrode mixture layer (liquid composition for forming a positive electrode mixture layer) is applied to a part of the surface of a positive electrode substrate to form a positive electrode mixture layer. When producing a negative electrode, an electrode mixture layer-forming liquid composition (negative electrode mixture layer-forming liquid composition) is applied to a part of the surface of a negative electrode substrate to form a negative electrode mixture layer.

[0095] The means for applying the liquid composition for forming the electrode composite layer is not particularly limited and can be appropriately selected depending on the purpose. Examples include a comma coater method, a die coater method, a curtain coat method, a spray coat method, and a liquid ejection method (inkjet method, IJ method).

[0096] <<Electrode mixture layer forming liquid composition heating step and electrode mixture layer forming liquid composition heating means>> The electrode mixture layer forming liquid composition heating step is a step of heating the electrode mixture layer forming liquid composition applied onto the substrate. The electrode mixture layer forming liquid composition heating means is a means for heating the electrode mixture layer forming liquid composition applied onto the substrate. The electrode mixture layer forming liquid composition heating step can be suitably carried out by an electrode mixture layer forming liquid composition heating means.

[0097] The heating means (process) for the liquid composition for forming an electrode composite layer is not particularly limited and can be selected appropriately depending on the purpose. Examples include a method of heating the coated surface using a resistance heater, an infrared heater, a fan heater, etc., and a method of drying the coated surface from the back side using a hot plate, a drum heater, etc. From the viewpoint of uniformly heating and drying the coated surface, a resistance heater, an infrared heater, or a fan heater capable of drying the coated surface without contact is preferred. These heating mechanisms may be used alone or in combination of two or more.

[0098] The heating temperature in the electrode mixture layer forming liquid composition heating step is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of protecting the substrate and the active material of the electrode mixture layer, it is preferably 70°C or higher and 150°C or lower.

[0099] <Insulating layer forming step and insulating layer forming means> The insulating layer forming step is a step of forming an insulating layer so as to cover the boundary between the exposed portion of the substrate where the substrate is exposed and the electrode mixture layer. The insulating layer forming step preferably includes an insulating layer forming liquid composition applying step and an insulating layer forming liquid composition heating step. The insulating layer forming means is a means for forming an insulating layer so as to cover the boundary between the exposed portion of the substrate where the substrate is exposed and the electrode mixture layer, and preferably includes an insulating layer forming liquid composition applying means and an insulating layer forming liquid composition heating means. The insulating layer forming step can be suitably carried out by an insulating layer forming means.

[0100] <<Insulating layer forming liquid composition applying step and insulating layer forming liquid composition applying means>> The insulating layer forming liquid composition applying step is a step of applying the insulating layer forming liquid composition to the boundary between the exposed portion of the substrate where the substrate is exposed and the electrode mixture layer. The insulating layer forming liquid composition applying means is a means for applying the insulating layer forming liquid composition to the boundary between the exposed portion of the substrate where the substrate is exposed and the electrode mixture layer. The step of applying the insulating layer-forming liquid composition can be suitably carried out by an insulating layer-forming liquid composition applying means.

[0101] As a means for applying the liquid composition for forming an insulating layer, a liquid ejection method such as an ink jet method, which is capable of non-contact and on-demand application, is preferred.

[0102] <<Insulating layer forming liquid composition heating step and insulating layer forming liquid composition heating means>> The insulating layer forming liquid composition heating step is a step of heating the applied insulating layer forming liquid composition. The insulating layer forming liquid composition heating means is a means for heating the applied insulating layer forming liquid composition. The insulating layer forming liquid composition heating step can be suitably carried out by means of an insulating layer forming liquid composition heating means.

[0103] The means (step) for heating the insulating layer-forming liquid composition is not particularly limited and can be appropriately selected depending on the purpose, and examples include a method of heating the coated surface with a resistance heater, infrared heater, fan heater, etc., and a method of drying from the backside of the coated surface with a hot plate, drum heater, etc. From the viewpoint of uniformly heating and drying the coated surface, a resistance heater, infrared heater, or fan heater that can dry the coated surface without contact is preferred. These heating mechanisms may be used alone or in combination of two or more.

[0104] The heating temperature in the step of heating the liquid composition for forming an insulating layer is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of protecting the substrate and the active material of the electrode mixture layer, it is preferably 70°C or higher and 150°C or lower. It is preferable that the heating temperature in the step of heating the insulating layer-forming liquid composition is 70° C. or higher, since this improves the strength of the insulating layer. It is preferable that the heating temperature in the insulating layer-forming liquid composition heating step is 150° C. or less, since this can prevent bubbles resulting from bumping on the insulating layer surface.

[0105] <Other steps and other means> The other steps are not particularly limited and can be selected appropriately depending on the purpose. Examples of the other steps include a step of forming an adhesive layer between the substrate and the electrode mixture layer, an opening forming step of forming openings of a desired size in the electrode mixture layer, a solid electrolyte filling step of filling the openings with a solid electrolyte, a step of forming an adhesive layer between the electrode mixture layer and the insulating layer, and a cutting step of cutting the electrodes to a desired size by punching or the like. The other means are not particularly limited and can be appropriately selected depending on the purpose. Examples include a means for forming an adhesive layer between the substrate and the electrode mixture layer, an opening forming means for forming an opening of a desired size in the electrode mixture layer, a solid electrolyte filling means for filling the opening with a solid electrolyte, a means for forming an adhesive layer between the electrode mixture layer and the insulating layer, and a cutting means for cutting the electrode to a desired size by punching or the like. Other steps may be suitably carried out by other means.

[0106] Here, an embodiment of an electrode manufacturing apparatus according to the present invention will be described with reference to the drawings, although the present invention is not limited to these embodiments. In each drawing, the same components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0107] [Figure 4] FIG. 4 is a schematic diagram showing an electrode manufacturing apparatus according to one embodiment of the present invention. 4 ejects insulating layer-forming liquid composition 130A onto electrode element 140 having negative electrode composite layer 120 provided on negative electrode substrate 110. Insulating layer-forming liquid composition 130A is stored in tank 307 and is supplied from tank 307 to liquid ejection head 306 via tube 308.

[0108] The liquid ejection device 300 may be provided with a mechanism for capping the nozzle of the liquid ejection head 306 to prevent the insulating layer forming liquid composition 130A from drying out when it is not being ejected from the liquid ejection head 306.

[0109] When manufacturing a negative electrode, the electrode element 140 is placed on a heatable stage 200, and then droplets of the insulating layer-forming liquid composition 130A are ejected onto the electrode element 140, followed by heating. At this time, the stage 200 or the liquid ejection head 306 may be moved. When the insulating layer forming liquid composition 130A discharged onto the electrode element 140 is heated, it may be heated by the stage 200 or by a heating mechanism other than the stage 200.

[0110] The heating temperature is not particularly limited as long as it is a temperature at which the dispersion medium can be volatilized, and is preferably in the range of 70°C to 150°C from the viewpoint of power consumption. When the insulating layer forming liquid composition 130A discharged onto the electrode element 140 is heated, ultraviolet light may be irradiated. As a result, an electrode (negative electrode) 400 in which the insulating layer 130 is formed on the electrode element 140 is obtained.

[0111] In this embodiment, an example has been shown in which the insulating layer 130 is formed on the electrode element 140 in which the negative electrode composite layer 120 has been previously provided on the negative electrode substrate 110. However, the electrode element 140 on which the insulating layer 130 is formed may be one in which the negative electrode composite layer 120 has been formed on the negative electrode substrate 110 in the same line as the device shown in FIG. 4.

[0112] [Figure 5] FIG. 5 is a schematic diagram showing an electrochemical device according to one embodiment of the present invention. 5 shows an electrochemical element 700 in which a positive electrode 500 having a positive electrode composite layer 501 and an insulating layer 13 provided on a positive electrode substrate 501 and a negative electrode 400 having a negative electrode composite layer 402 and an insulating layer 13 provided on a negative electrode substrate 401 are disposed as opposing electrodes via a separator 600. Meanwhile, a treatment liquid 7 (a solution containing a non-aqueous solvent and an electrolyte) is stored in a liquid bath 6, and the electrochemical element 700 is immersed in this. In this state, a voltage may be applied to the electrochemical element 700. The insulating layer 13 may be formed on at least one of the negative electrode 400 and the positive electrode 500, or may be formed on both.

[0113] The electrochemical device 700 may be mounted on a portable device, etc. In this specification, an item on which the electrochemical device 700 is mounted may be referred to as a mounted item. The electrochemical element 700 and the substrate portion of the mounted item on which the electrochemical element 700 is provided may be bonded by an adhesive. In other words, the electrochemical element 700 and the substrate portion of the mounted item on which the electrochemical element 700 is provided may be bonded via an adhesive layer derived from an adhesive.

[0114] The number of electrochemical elements 700 mounted on the mounted product is not particularly limited and can be selected appropriately depending on the purpose, but a plurality is preferable. In a mounted product mounting a plurality of electrochemical elements 700, at least two electrochemical elements 700 are preferably joined in an L-shape and arranged on the substrate of the mounted product. Note that it is preferable that the joining regions of the at least two electrochemical elements 700 do not overlap with the bonding regions where the electrochemical elements 700 and the mounted product are bonded with an adhesive.

[0115] The adhesive is not particularly limited and can be appropriately selected depending on the purpose.

[0116] The mounted component may have other members different from the electrochemical element 700 in an area different from the area where the electrochemical element 700 is adhered. The other members are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include heat exhaust members including a heat exhaust fan and a heat exhaust pipe.

[0117] The mounted item and other components may be bonded with an adhesive. For example, if the mounted item and other components are fixed with screws or the like, there is a risk that the fixed position may change due to loosening of the screws. By bonding with an adhesive, the electrochemical element and the heat dissipation member can be fixed in a predetermined position and are also resistant to vibration, so that heat generated when the mounted item (e.g., a portable device) is operated using the energy of the electrochemical element can be efficiently and reliably dissipated.

[0118] When mounting the electrochemical element 700 or other components on the mount, the adhesive may be applied by an inkjet method, which allows for precise application in a desired shape. When applying the adhesive by the inkjet method, from the viewpoint of productivity, it is preferable to apply the adhesive to the adhesive portion between the electrochemical element 700 and the mount and the adhesive portion between the other components and the mount in a single scan of the inkjet head.

[0119] (Electricity storage device) The electricity storage device of the present invention includes an electrode. As the electrodes, the same ones as those in the (electrodes) section of this specification can be used, and therefore a duplicated description will be omitted.

[0120] Here, an embodiment of the electricity storage device of the present invention will be described with reference to the drawings, although the present invention is not limited to these embodiments. In each drawing, the same components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0121] [Figure 6] FIG. 6 is a schematic diagram showing an electricity storage device according to one embodiment of the present invention. In the electricity storage device 800, an electrolyte layer 51 made of a non-aqueous electrolyte is formed on a stacked electrode 40, and the device is sealed with an exterior case 52. In the electricity storage device 800, the lead wires 41 and 42 are drawn out to the outside of the exterior case 52. The laminated electrode 40 is formed by laminating a negative electrode 400 and a positive electrode 500 with a separator 600 interposed therebetween. The positive electrode 500 is laminated on both sides of the negative electrode 400. A lead wire 41 is connected to the negative electrode substrate 401, and a lead wire 42 is connected to the positive electrode substrate 501. Negative electrode 400 has negative electrode composite layer 402 and insulating layer 13 formed in this order on both sides of negative electrode substrate 401 . Positive electrode 500 has positive electrode composite layer 502 and insulating layer 13 formed in this order on both sides of positive electrode substrate 501 . The number of negative electrodes 400 and the number of positive electrodes 500 in the stacked electrode 40 may be the same or different. The insulating layer 13 may be formed on at least one of the negative electrode 400 and the positive electrode 500, or may be formed on both.

[0122] The shape of the electricity storage device using the electrodes is not particularly limited, and examples thereof include a laminate type in which flat electrodes are stacked, a cylinder type in which a sheet electrode and a separator are spirally wound, a cylinder type with an inside-out structure in which a pellet electrode and a separator are combined, and a coin type in which a pellet electrode and a separator are stacked. The power storage device 800 may include other components as necessary.

[0123] <<Non-aqueous electrolyte>> The non-aqueous electrolyte may be, for example, a non-aqueous electrolytic solution, which is an electrolytic solution in which an electrolyte salt is dissolved in a non-aqueous solvent. The non-aqueous solvent used in the non-aqueous electrolyte is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include aprotic organic solvents. There are no particular limitations on the electrolyte salt, as long as it has high ionic conductivity and is soluble in a non-aqueous solvent. Examples of cations constituting the electrolyte salt include lithium ions. The anion constituting the alkali metal salt is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that it contains a halogen atom. - , PF6 - , AsF6 - , CF3SO3 - , (CF3SO2)2N - , (C2F5SO2)2N - Examples include: The alkali metal salt is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide. These may be used alone or in combination of two or more. The concentration of the electrolyte salt in the non-aqueous electrolyte solution is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 mol / L or more and 4 mol / L or less.

[0124] <<Separator>> The separator 600 is provided between the negative electrode 400 and the positive electrode 500 as needed to prevent short-circuiting between the negative electrode 400 and the positive electrode 500 . The separator is a porous film having communicating pores that insulates and separates a positive electrode and a negative electrode used in an electrochemical element such as a secondary battery. The separator is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include paper such as kraft paper, vinylon-mixed paper, and synthetic pulp-mixed paper, cellophane, polyethylene graft membrane, polyolefin nonwoven fabric such as polypropylene melt-blown nonwoven fabric, polyamide nonwoven fabric, glass fiber nonwoven fabric, and micropore membrane. The size of the separator is not particularly limited as long as it can be used in an electrochemical element. The separator may have a single layer structure or a laminated structure. When a solid electrolyte is used as the non-aqueous electrolyte, the separator 600 can be omitted.

[0125] The use of the electricity storage device is not particularly limited and can be appropriately selected depending on the purpose. Examples include laptop computers, smart devices, e-book players, portable fax machines, portable copiers, portable printers, headphone stereos, video movie players, liquid crystal televisions, handheld vacuum cleaners, portable CDs, minidiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, lighting equipment, toys, game devices, clocks, strobe lights, and cameras. As described above, the electricity storage device of this embodiment has the electrode of this embodiment, and thereby can obtain the same effects as the electrode of this embodiment. [Example]

[0126] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0127] Example 1 <Preparation of Liquid Composition for Forming Insulating Layer> A pre-dispersion liquid containing 45.0 parts by weight of LS-711CB (α-alumina, manufactured by Nippon Light Metal Co., Ltd.) as insulating inorganic particles, 1.35 parts by weight of GK570 (manufactured by Daikin Corporation) as an insulating layer binder, 1.35 parts by weight of AKM0531 (manufactured by NOF Corporation) as a dispersant, and 52.3 parts by weight of ethyl lactate as a dispersion medium was mixed and placed in a glass ball mill pot along with 5 mm diameter zirconium beads. The sealed pot was placed on a mill turntable and dispersed to obtain a liquid composition for forming an insulating layer. The pot rotation speed during dispersion was 35 rpm, and dispersion was determined to be complete when the viscosity change reached a steady state.

[0128] <Preparation of negative electrode> A liquid composition for forming a negative electrode mixture layer was prepared by mixing 97 parts of graphite (manufactured by JFE Chemical Corporation, model number BTM-DMP), 1 part by mass of a thickener (carboxymethyl cellulose, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., model number CELLOGEN HS-6), 2 parts by mass of a polymer (acrylic resin, manufactured by Zeon Corporation, model number AZ-9129), and 100 parts by mass of water as a solvent. The liquid composition for forming a negative electrode composite layer was applied to a copper negative electrode substrate (manufactured by Furukawa Electric Co., Ltd., model number NC-WS, foil thickness 10 μm) and then dried to obtain a coating amount per unit area (area density) of 9 mg / cm on one side. 2 The thickness of the negative electrode was 216 μm, and the volume density of the negative electrode was 0.91 g / cm 3 It was. Next, the volume density of the negative electrode was measured using a roll press machine until it reached 1.6 g / cm 3 The negative electrode was then pressed to obtain a negative electrode.

[0129] <Preparation of positive electrode> The positive electrode active material was 93 parts by mass of lithium nickel cobalt manganese oxide (NCM622, manufactured by Beijing Dongben), the conductive additive (Ketjenblack, manufactured by Lion Specialty Chemical Co., Ltd., model number 600JD) was 3 parts by mass, and the electrode composite layer binder was 4 parts by mass of PVDF (polyvinylidene fluoride, manufactured by Solvay, model number Solef5130). These were dispersed in N-methylpyrrolidone (NMP) (manufactured by Mitsubishi Chemical Corporation) to prepare a slurry. This slurry was applied to an aluminum positive electrode substrate (manufactured by UACJ Corporation, model number 1N30) and then dried to a coating amount per unit area (area density) of 15.0 mg / cm. 2 Next, the volume density of the positive electrode was reduced to 3.4 g / cm using a roll press. 3 The resultant was compression molded to obtain a positive electrode.

[0130] <Formation of insulating layer> The insulating layer-forming liquid composition was printed along the boundary between the exposed portion of the positive electrode substrate and the positive electrode composite layer in a width of 10 mm, a covering width of 1 mm, and a film thickness of 5 μm at the exposed portion of the positive electrode substrate using an inkjet head (MH2420, manufactured by Ricoh Co., Ltd.).

[0131] <Fabrication of electrochemical devices> The prepared positive and negative electrodes were alternately stacked with film separators (Toray Industries, Inc., model number F20BHE) between them to form an electrode element with three positive electrodes and four negative electrodes stacked together. The uncoated portions of the electrodes were then joined together, and a nickel tab serving as a negative electrode lead wire was welded to the negative electrode, and an aluminum tab serving as a positive electrode lead wire was welded to the positive electrode. This electrode element was impregnated with a nonaqueous electrolyte solution of 1.5 M LiPF6 (EC:DMC:EMC = 1:1:1) and sealed in an aluminum laminate film to form a lithium ion secondary battery as an electrochemical element.

[0132] (Examples 2 to 30, Comparative Examples 1 to 6) Liquid compositions for forming an insulating layer and lithium ion secondary batteries were produced in the same manner as in Example 1, except that the formulation of the liquid composition for forming an insulating layer was changed as shown in Tables 1 to 6.

[0133] The details of the materials used in each example and each comparative example are as follows.

[0134] -Binder- GK570 (weight average molecular weight Mw: 28,000, number average molecular weight Mn: 12,000, manufactured by Daikin Corporation) LF200F (weight average molecular weight Mw: 42,000, number average molecular weight Mn: 15,000, manufactured by AGC) GF-X-101 (weight average molecular weight Mw: 27,000, number average molecular weight Mn: 12,000, manufactured by Toagosei Co., Ltd.) GF-400 (weight average molecular weight Mw: 77,000, number average molecular weight Mn: 26,000, manufactured by Toagosei Co., Ltd.) ·SSA-100 (weight average molecular weight Mw: 38,000, number average molecular weight Mn: 14,000, manufactured by Seiko PMC Co., Ltd.) JMR-10H (weight average molecular weight Mw: 60,000, number average molecular weight Mn: 30,000, manufactured by Nippon Vaccination & Poval Co., Ltd.) EPI-5310 (weight average molecular weight Mw: 60,000, number average molecular weight Mn: 30,000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) LF916F (weight average molecular weight Mw: 11,000, number average molecular weight Mn: 5,000, manufactured by AGC) ·solef5130 (weight average molecular weight Mw: 1,100,000, manufactured by solvay) Kureha #9100 (weight average molecular weight Mw: 280,000, manufactured by Kureha Corporation) KF850 (weight average molecular weight Mw: 200,000, manufactured by Kureha Corporation)

[0135] -Dispersant- AKM0531 (NOF Corporation) SC0505K (NOF Corporation) ISOBAM-10 (Kuraray Co., Ltd.) HKM-50A (NOF Corporation) DISPERBYK-108 (BYK) DISPERBYK2000 (manufactured by BYK) SN Dispersant 9228 (manufactured by San Nopco Ltd.)

[0136] -Insulating inorganic particles- LS-711CB (Nippon Light Metal Co., Ltd.) CT-3000LSSG (manufactured by Almatis) SEPal-60 (manufactured by Alteo) AKP-3000 (Sumitomo Chemical Co., Ltd.) BMB-07 (Kawai Coal Industries Co., Ltd.) F-10 (Showa Denko Co., Ltd.) TZ-3YS (Tosoh Corporation) AA07 (Sumitomo Chemical Co., Ltd.) AA1.5 (Sumitomo Chemical Co., Ltd.)

[0137] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the binder were measured by gel permeation chromatography (GPC). A high-speed GPC system (GPC-8020, Tosoh Corporation) was connected to columns TSK G2000HXL and G4000HXL (Tosoh Corporation). The column temperature was set to 40°C, and tetrahydrofuran (Fujifilm Wako Pure Chemical Industries, Ltd.) containing the stabilizer BHT was passed through the column at a flow rate of 1.0 mL / min. The same solvent used to pass the sample through the system was used to prepare the measurement sample, and the resin concentration was adjusted to 0.5% by mass. The measurement volume was 10 μL. For analysis, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were calculated based on a molecular weight calibration curve prepared using monodisperse polystyrene standard samples (Tosoh Corporation).

[0138] <Evaluation of Thixotropy of Liquid Composition for Forming Insulating Layer> The thixotropy of each insulating layer-forming liquid composition was evaluated using an E-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.). The viscosity measured using a standard rotor of 1°34' x R24 at a rotation speed of 100 rpm was defined as viscosity A, and the viscosity measured at a rotation speed of 10 rpm was defined as viscosity B. The ratio of viscosity B to viscosity A [B / A] was calculated and evaluated. Two samples were used, and the average value was used. A rating of "△" or better was considered acceptable. [Evaluation criteria] ○: The ratio [B / A] is between 0.95 and 1.05. △: The ratio [B / A] is 0.8 or more and less than 0.95, or more than 1.05 and less than 1.2. ×: The ratio [B / A] is less than 0.8 or more than 1.2

[0139] <Evaluation of ejection properties of liquid composition for forming insulating layer> The ejection properties of each insulating layer-forming liquid composition were evaluated using an inkjet head (MH2420, manufactured by Ricoh Co., Ltd.), and a rating of "Fair" or better was considered to be acceptable. [Evaluation criteria] ○: Discharge was possible from all nozzles for 10 minutes continuously △: Some nozzles had ejection abnormalities such as deflected ejection or poor ejection speed, but all nozzles were able to eject. ×: Non-ejection occurred in some nozzles

[0140] <Evaluation of Continuous Dischargeability of Liquid Composition for Forming Insulating Layer> Each liquid composition for forming an insulating layer was continuously discharged for 30 minutes using an inkjet head (manufactured by Ricoh Co., Ltd., MH2420), and the discharge state was compared after 1 minute and after 30 minutes. A rating of "△" or better was considered to be acceptable. [Evaluation criteria] 〇: No change in discharge state after 30 minutes of continuous discharge △: After 30 minutes of continuous ejection, some nozzles exhibited ejection abnormalities such as deflected ejection or poor ejection speed, but all nozzles were able to eject. ×: After 30 minutes of continuous ejection, some nozzles failed to eject.

[0141] <Evaluation of redispersibility> 400 mL of each liquid composition for forming an insulating layer was placed in an i-boy container, the lid was closed, and the composition was left to stand at room temperature for 30 days. After that, a re-dispersion was obtained by stirring for 1 hour using a stirring device (SKH-40SA, manufactured by Misugi Co., Ltd.). The re-dispersion was diluted to a solid content of 10% by mass or less, and the median diameter D50 of the insulating inorganic particles in the liquid composition for forming an insulating layer was measured using a concentrated particle size analyzer (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.). The rate of change (particle diameter) from the particle diameter before storage was evaluated. A grade of "△" or better was considered acceptable. [Evaluation criteria] ○: Change rate is less than ±5% △: Change rate is between ±5% and ±15% ×: Change rate is ±15% or more

[0142] <Evaluation of strength (before cycle test)> Peel strength was evaluated using a positive electrode with an insulating layer formed. The evaluation equipment used was a light-load adhesive / film peeling analyzer (VPA-3S, manufactured by Kyowa Interface Science Co., Ltd.) and 8 mm wide tape (cellophane tape, manufactured by Nitto Co., Ltd.). The tape was attached to the insulating layer and peeled at a peel angle of 90 degrees and a peeling speed of 30 mm / min. The average load applied to the load cell was read to evaluate the strength. [Evaluation criteria] 〇: Peel strength is 50N / m or more ×: Peel strength is less than 50 N / m

[0143] <Evaluation of strength (after cycle test)> The positive and negative electrode leads of each lithium-ion secondary battery were connected to a charge / discharge tester (Hokuto Denko Corporation, Model No. HJ0610SD8Y) and charged at a constant current and constant voltage of 4.2 V at a current rate of 0.2 C for 5 hours. After charging, the battery was placed in a thermostatic chamber at 40°C for 5 days. The battery was then discharged at a constant current of 0.2 C to 2.5 V. The battery was then charged at a constant current and constant voltage of 4.2 V at a current rate of 0.2 C for 5 hours, followed by a 10-minute break and then discharged at a constant current of 0.2 C to 2.5 V. The discharge capacity at this time was recorded as the initial capacity. For this evaluation, cells with a discharge capacity within the range of 180 mAh ± 1.8 mAh were used. Using the initial capacity as the standard for full charge, the battery was fully charged from a discharged state to a voltage of 4.2 V at a current rate of C, and then discharged to 2.5 V at a current rate of 2 C for 300 cycles as a cycle test. The cycle test was carried out in an Espec thermostatic chamber at 45°C. After the cycle test, the sample was disassembled, the positive electrode was removed, and after lightly washing it with dimethyl carbonate (DMC), the remaining state of the insulating layer at the boundary was confirmed. [Evaluation criteria] 〇: The insulating layer remains, and 90% or more of the printing width is maintained compared to the original printing width. ×: The insulating layer is partially peeled off, and less than 90% of the printing width is maintained compared to the printing width.

[0144] [Table 1]

[0145] [Table 2]

[0146] [Table 3]

[0147] [Table 4]

[0148] [Table 5]

[0149] [Table 6]

[0150] The results of Examples 1 to 5, 8 to 13, 16 to 18, 22 to 23, and 26 show that by satisfying all of the preferred aspects of the binder, dispersant, and insulating inorganic particles, an insulating layer having excellent ejectability, continuous ejectability, and redispersibility as well as excellent strength can be obtained. The results of Examples 6 and 14 show that if the ratio of binder to insulating inorganic particles is too high, the redispersibility, ejectability, continuous ejectability, and thixotropy decrease. The results of Example 7 show that if the ratio of the binder (GK570) to the insulating inorganic particles is too low, the ejection properties and the film strength after the cycle test decrease. The results of Example 15 show that if the ratio of the dispersant (AKM0531) to the insulating inorganic particles is too high, the ejection properties, continuous ejection properties, and thixotropy are reduced. The results of Examples 19 to 21 show that if the dispersant does not contain the structural unit represented by general formula (1) and the structural unit represented by general formula (2), the ejection properties, continuous ejection properties, and thixotropy are reduced. The results of Examples 24 and 25 show that unless alumina is used as the insulating inorganic particles, redispersibility and continuous dischargeability decrease. The results of Example 27 show that when the particle size of the insulating inorganic particles is large, the viscosity of the liquid composition increases, and the ejection properties and continuous ejection properties decrease. The results of Example 28 show that when the binder type is styrene acrylic resin, the film strength after the cycle test decreases. The results of Example 29 show that when the binder type is polyvinyl alcohol resin, the thixotropy and film strength after the cycle test decrease. The results of Example 30 show that when the binder type is a polyimide resin, the ejection property, continuous ejection property, thixotropy, and film strength after the cycle test decrease.

[0151] The results of Comparative Examples 1 to 4 show that when the binder has a fluoroethylene group and a vinyl ether group and a weight average molecular weight of 25,000 or more and 80,000 or less, an insulating layer having excellent dischargeability, continuous dischargeability, and redispersibility as well as excellent strength can be obtained. The results of Comparative Examples 5 and 6 show that when the dispersant has a carboxyl group or an acid anhydride group, an insulating layer having excellent dischargeability, continuous dischargeability, and redispersibility as well as excellent strength can be obtained.

[0152] The present invention includes, for example, the following aspects. <1> insulating inorganic particles; a dispersant having a carboxyl group or an acid anhydride group; A liquid composition for forming an insulating layer, comprising: The liquid composition for forming an insulating layer is characterized in that the weight average molecular weight of the binder is 25,000 or more and 80,000 or less. <2> The binder has a fluoroethylene group and a vinyl ether group. <1> 1. The liquid composition for forming an insulating layer according to claim 1. <3> The dispersant contains at least one selected from the group consisting of a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3): <1> or the above <2> 1. The liquid composition for forming an insulating layer according to claim 1. [ka] [ka] [ka] (In the general formulae (1) to (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.) <4> The viscosity measured using an E-type viscometer at 100 rpm is defined as viscosity A, and the viscosity measured using an E-type viscometer at 10 rpm is defined as viscosity B. The ratio of viscosity B to viscosity A [B / A] is 0.95 or more and 1.05 or less. <1> From the above <3> 1. The liquid composition for forming an insulating layer according to claim 1, wherein the insulating layer is a liquid composition for forming an insulating layer. <5> The insulating inorganic particles are α-alumina or boehmite. <1> From the above <4> 1. The liquid composition for forming an insulating layer according to claim 1, wherein the insulating layer is a liquid composition for forming an insulating layer. <6> The median diameter of the insulating inorganic particles is 200 nm or more and less than 1,000 nm. <1> From the above <5> 1. The liquid composition for forming an insulating layer according to claim 1, wherein the insulating layer is a liquid composition for forming an insulating layer. <7> The aforementioned <1> From the above <6> 1. A container for storing the liquid composition for forming an insulating layer according to any one of the above. <8> The aforementioned <1> From the above <6> a container containing the insulating layer-forming liquid composition according to any one of the above items; and an insulating layer forming liquid composition applying means for applying the insulating layer forming liquid composition onto a substrate. <9> The liquid composition for forming an insulating layer is applied by an ink jet. <8> 2. An apparatus for manufacturing an electrode according to claim 1. <10> a substrate; an electrode mixture layer provided on a portion of the substrate; an insulating layer covering a boundary between the exposed portion of the substrate and the electrode mixture layer, the insulating layer includes insulating inorganic particles, a dispersant, and a binder; The dispersant contains at least one selected from a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3), The electrode is characterized in that the weight average molecular weight of the binder is 25,000 or more and 80,000 or less. [ka] [ka] [ka] (In the general formulae (1) to (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.) <11> The binder has a fluoroethylene group and a vinyl ether group. <10> The electrode is described in <12> The insulating layer is provided at the boundary portion and at an end portion on the electrode mixture layer. <10> or the above <11> The electrode is described in <13> the insulating layer is provided on the boundary portion and on the upper surface of the electrode mixture layer; <10> or the above <11> The electrode is as described. <14> The peel strength of the insulating layer to the substrate is 50 N / m or more. <10> From the above <13> The electrode is any one of the above. <15> The aforementioned <10> From the above <14> 10. An electricity storage device comprising the electrode according to any one of the above items.

[0153] <1> from <6> The liquid composition for forming an insulating layer according to any one of <7> The storage container according to <8> or <9> An electrode manufacturing apparatus according to the present invention, <10> from <14> The electrode according to any one of the preceding claims, and <15> The electricity storage device described in the above can solve the various problems in the prior art and achieve the object of the present invention. [Explanation of symbols]

[0154] 100 electrodes 1 Base 11 Exposed base part 2 Electrode composite layer 3. Insulation layer [Prior art documents] [Patent documents]

[0155] [Patent Document 1] Patent No. 6887103 [Patent Document 2] Japanese Patent Publication No. 2023-091628 [Patent Document 3] Japanese Patent Application Publication No. 2023-131728

Claims

1. Inorganic particles; a dispersant having a carboxyl group or an acid anhydride group; A liquid composition for forming an insulating layer, comprising: The weight average molecular weight of the binder is 25,000 or more and 80,000 or less, the content of the binder is 1% by mass or more and 5% by mass or less with respect to the total amount of insulating inorganic particles in the insulating layer, The liquid composition for forming an insulating layer, wherein the binder has a fluoroethylene group and a vinyl ether group.

2. 2. The liquid composition for forming an insulating layer according to claim 1, wherein the dispersant contains at least one selected from a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3): 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 (In general formulas (1) to (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.)

3. 3. A liquid composition for forming an insulating layer according to claim 1 or 2, wherein the viscosity measured using an E-type viscometer at 100 rpm is defined as viscosity A, and the viscosity measured using an E-type viscometer at 10 rpm is defined as viscosity B, and the ratio of viscosity B to viscosity A [B / A] is 0.95 or more and 1.05 or less.

4. 3. The liquid composition for forming an insulating layer according to claim 1, wherein the inorganic particles are α-alumina or boehmite.

5. 3. The liquid composition for forming an insulating layer according to claim 1, wherein the inorganic particles have a median diameter of 200 nm or more and less than 1,000 nm.

6. A container that contains the insulating layer-forming liquid composition according to claim 1 or 2.

7. A container containing the insulating layer-forming liquid composition according to claim 1 or 2; and an insulating layer forming liquid composition applying means for applying the insulating layer forming liquid composition onto a substrate.

8. 8. The electrode manufacturing apparatus according to claim 7, wherein the insulating layer forming liquid composition applying means is an inkjet.

9. a substrate; an electrode mixture layer provided on a portion of the substrate; an insulating layer covering a boundary between the exposed portion of the substrate and the electrode mixture layer, the insulating layer includes inorganic particles, a dispersant, and a binder; The dispersant contains at least one selected from a structural unit represented by the following general formula (1), a structural unit represented by the following general formula (2), and a structural unit represented by the following general formula (3), The weight average molecular weight of the binder is 25,000 or more and 80,000 or less, the content of the binder is 1% by mass or more and 5% by mass or less with respect to the total amount of insulating inorganic particles in the insulating layer, The electrode, wherein the binder has a fluoroethylene group and a vinyl ether group. 【Chemistry 4】 【Transformation 5】 【Transformation 6】 (In general formulas (1) to (3), * represents a bonding site to an adjacent main chain structural unit, and M represents an ammonium salt.)

10. 10. The electrode of claim 9, wherein the binder comprises fluoroethylene groups and vinyl ether groups.

11. The electrode according to claim 9 , wherein the insulating layer is provided at the boundary portion and at an end portion on the electrode mixture layer.

12. The electrode according to claim 9 , wherein the insulating layer is provided on the boundary portion and on the upper surface of the electrode mixture layer.

13. 10. The electrode of claim 9, wherein the peel strength of the insulating layer to the substrate is 50 N / m or greater.

14. An electrochemical device comprising the electrode according to any one of claims 9 to 13.

15. An on-board item characterized by comprising the electrochemical element described in claim 14.

16. A method for manufacturing an electrode having a substrate, an electrode mixture layer provided on a portion of the substrate and containing an active material, and an insulating layer provided so as to cover a boundary between an exposed portion of the substrate and the electrode mixture layer, the method comprising: a liquid composition applying step of applying a liquid composition so as to cover the boundary portion, The liquid composition contains inorganic particles, a dispersant having a carboxyl group or an acid anhydride group, and a binder, The weight average molecular weight of the binder is 25,000 or more and 80,000 or less, the content of the binder is 1% by mass or more and 5% by mass or less with respect to the total amount of insulating inorganic particles in the insulating layer, The method for manufacturing an electrode, wherein the binder has a fluoroethylene group and a vinyl ether group.

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