Method for manufacturing electrodes, and method for manufacturing electrochemical elements

Abstract

To provide a liquid composition for forming an insulating layer that is excellent in dischargeability, continuous dischargeability, and redispersibility, as well as providing an insulating layer with excellent strength. [Solution] Insulating inorganic particles, A dispersant having a carboxyl group or an acid anhydride group, A liquid composition for forming an insulating layer, comprising a binder, 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.

Description

Technical Field

[0001] The present invention relates to a liquid composition for forming an insulating layer, a storage container, an electrode and a manufacturing apparatus thereof, and a power storage device.

Background Art

[0002] Conventionally, in power storage devices such as lithium ion secondary batteries, electric double layer capacitors, lithium ion capacitors, and redox capacitors, paper, non-woven fabrics, porous films, etc. are used as separators for the purpose of preventing short circuits between the positive electrode and the negative electrode. When the separator melts or shrinks due to overheating, an internal short circuit may occur. At this time, the separator further shrinks due to the short circuit reaction heat generated instantaneously. Then, the short circuit portion expands and abnormal heating is promoted, and the battery may heat run away and catch fire. For the purpose of preventing such a short circuit reaction, a technique of providing an insulating layer at a location where an internal short circuit is likely to occur has been proposed.

[0003] For example, for the purpose of suppressing the rise in battery temperature after an internal short circuit due to foreign matter contamination, it has a protective layer that covers the boundary between the exposed portion (where the current collector is exposed and the active material layer is not formed) and the active material layer, and the protective layer is a non-aqueous electrolyte secondary battery containing a curable resin and inorganic particles has been proposed (see, for example, Patent Document 1). In addition, for the purpose of improving the strength of the insulating layer, maintaining battery characteristics, and achieving good stability, etc., an electrochemical element or electrode provided with an insulating layer containing a compound having a hydroxyl group at the end as a binder and a compound having a carboxyl group as a dispersant has been proposed (see, for example, Patent Documents 2 to 3).

Summary of the Invention

Problems 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 dischargeability, continuous dischargeability, and redispersibility, and can obtain an insulating layer excellent in strength.

Means for Solving the Problems

[0005] The liquid composition for forming an insulating layer of the present invention, as a means for solving the problem, Insulating inorganic particles, A dispersant having a carboxyl group or an acid anhydride group, A liquid composition for forming an insulating layer, comprising a binder, The weight-average molecular weight of the binder is between 25,000 and 80,000. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a liquid composition for forming an insulating layer that has excellent discharge properties, continuous discharge properties, and redispersibility, as well as excellent strength. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view showing an electrode relating to an embodiment of the present invention. [Figure 2A] This is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 2B] This is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 3A] This is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 3B] This is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. [Figure 4] This is a schematic diagram showing an electrode manufacturing apparatus related to one embodiment of the present invention. [Figure 5] This is a schematic diagram showing an electrochemical element relating to one embodiment of the present invention. [Figure 6] This is a schematic diagram showing an energy storage device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] Inkjet printing is preferred as a means of applying an insulating layer-forming liquid composition with high positional accuracy, thinly and uniformly to an active material layer and substrate formed in a roll-to-roll production process, such as the non-aqueous electrolyte secondary battery described in Patent Document 1. Inkjet printing can apply the insulating layer-forming liquid composition to the appropriate position while detecting the boundary between the exposed current collector and the active material layer by controlling the ON / OFF of each nozzle, and the coating amount can be controlled by adjusting the amount of liquid droplets discharged from each nozzle hole. Generally, liquid compositions for forming insulating layers are obtained by uniformly dispersing solid components (inorganic particles, a binder, and a dispersant) in a solvent. Conventionally (including the invention described in Patent Document 1), polymer fluorine compounds such as polyvinylidene fluoride, curable resins, and modified rubbers have been used as binders for liquid compositions for forming insulating layers. However, these materials have high molecular weights, making it difficult to form droplets, and thus unsuitable for inkjet ejection. Furthermore, even when using binders with low molecular weights, there is a tendency for high thixotropy, which presents the problem of difficulty in stable continuous ejection by inkjet.

[0009] The electrochemical elements or electrodes described in Patent Documents 2-3 had a concern in the roll-to-roll production process: the insulating layer film strength was insufficient after drying and winding onto the roll, and some inorganic particles peeled off due to friction during winding, etc., and were mixed into the electrolyte as impurities.

[0010] The liquid composition for forming an insulating layer of the present invention can sufficiently resolve various concerns in the prior art. More specifically, it is possible to realize a liquid composition for forming an insulating layer that has excellent discharge properties and continuous discharge properties, as well as excellent strength. Furthermore, it is also possible to realize a liquid composition for forming an insulating layer that has excellent redispersibility, which is a basic performance characteristic.

[0011] The details of the present invention are described below.

[0012] (Liquid composition for forming an insulating layer) The liquid composition for forming an insulating layer 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 "liquid composition for forming an insulating layer" may sometimes be simply referred to as the "liquid composition". In this specification, the "dispersant having a carboxyl group or an acid anhydride group" may sometimes be simply referred to as the "dispersant". In this specification, the "binder" may sometimes be referred to as the "binder for forming an insulating layer".

[0014] Since the liquid composition for forming an insulating layer of the present invention has low thixotropy, it is excellent in ejection properties and continuous ejection properties by inkjet, and also excellent in redispersibility after long-term storage. Further, when a film is formed from the liquid composition for forming an insulating layer, an insulating layer having excellent strength can be obtained, and the insulating layer does not peel off even when charge and discharge are repeated as a battery.

[0015] <Insulating inorganic particles> In this specification, "insulating property" means that the volume resistivity is 108 Ω·cm or more. That is, the insulating inorganic particles in the present invention mean inorganic particles having a volume resistivity of 108 Ω·cm or more.

[0016] The insulating inorganic particles are not particularly limited as long as the volume resistivity is 108 Ω·cm or more, and can be appropriately selected according to the purpose. For example, aluminum oxide (alumina), boehmite, silica, aluminum nitride, silicon nitride, cordierite, sialon, mullite, steatite, yttria, zirconia, silicon carbide, etc. can be mentioned. Among these, inorganic oxides are preferable, aluminum oxide and boehmite are more preferable, and α-alumina is even more preferable.

[0017] α-Alumina is known to function as a scavenger for "junk" chemical species, i.e., chemical species that can cause capacity fade in a lithium-ion secondary battery. Also, since alumina particles have good wettability and affinity for the electrolyte, the cycle performance of the lithium-ion secondary battery is improved. By using α-alumina as the insulating inorganic particles, the redispersibility and ejection property by inkjet are improved in the liquid composition, and the heat resistance is improved in the insulating layer. These insulating inorganic particles may be used alone or in combination of two or more.

[0018] The shape of the insulating inorganic particles is not particularly limited and can be appropriately selected according to the purpose. Examples include rectangular shape, spherical shape, elliptical shape, cylindrical shape, oval shape, dog bone shape, amorphous shape, etc. Among these, from the viewpoint of improving the ejection property by inkjet, it is preferable that the aspect ratio of the long side to the short side of the insulating inorganic particles is close to 1.

[0019] The median diameter of the insulating inorganic particles is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 200 nm or more and 1,000 nm or less. When the median diameter of the insulating inorganic particles is 200 nm or more, it is possible to suppress the particles from dancing in the air (generation of mist) during ejection by inkjet. Also, in the insulating layer, it is possible to suppress the adhesion of the insulating inorganic particles onto the substrate due to the lack of fine particles. When the median diameter of the insulating inorganic particles is 1,000 nm or less, it is possible to eliminate nozzle clogging during ejection by inkjet, and the ejection property is improved. Also, in the insulating layer, it is suitable because the thickness of the insulating layer is made uniform and homogenized (less unevenness).

[0020] There are no particular restrictions on the method for measuring the median diameter of insulating inorganic particles, and it can be appropriately selected depending on the purpose. For example, the liquid composition can be diluted so that the solid content is 10% by 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 a first insulating inorganic particle with a median diameter of 200 nm or more and less than 1,000 nm, and a second insulating inorganic particle with an average Stokes diameter of less than 30 nm. The average Stokes diameter refers to the average value of the major axis of the particles measured, for example, by observation with a transmission electron microscope (TEM). By including a second type of insulating inorganic particle with an average Stokes diameter of less than 30 nm, the energy barrier in the interaction potential energy between particles can be sufficiently reduced. This eliminates the problem that when the liquid composition is left standing for a long period of time and the insulating inorganic particles aggregate, the insulating inorganic particles do not redisperse even after re-stirring.

[0022] There are no particular restrictions on the content of insulating inorganic particles, and they can be appropriately selected depending on the purpose. However, from the viewpoint of ensuring a uniform thickness of the insulating layer after drying, it is preferable that the content be 20% to 50% by mass, more preferably 25% to 48% by mass, and even more preferably 35% to 45% by mass, based on the total amount of the liquid composition. If the content of insulating inorganic particles is 20% by mass or more relative to the total amount of the liquid composition, it is possible to suppress the leakage from the resulting insulating layer onto the substrate and electrode composite layer. When the content of insulating inorganic particles is 50% by mass or less of the total volume of the liquid composition, nozzle clogging during inkjet ejection can be eliminated, improving ejection performance. Furthermore, this is preferable because the insulating layer is homogenized.

[0023] As insulating inorganic particles, you may use those that you have synthesized as appropriate, or you may use commercially available ones. Examples of commercially available aluminum oxide as 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, AKP-G15 (all high-purity alumina, manufactured by Sumitomo Chemical Co., Ltd.), TM-DA, TM-DAR, TM-5D (all manufactured by Daimyo Chemical Industry Co., Ltd.), CT-3000LSSG (manufactured by Almatis), LS-502, LS-711CB, SLS-710 (manufactured by Nippon Light Metal Co., Ltd.), SEPal-60, SEPal-70 (manufactured by Alteo).

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

[0025] There are no particular restrictions on the dispersant having an acid anhydride group, and it can be appropriately selected depending on the purpose. For example, dispersants containing a structural unit represented by general formula (1) can be used.

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

[0027] There are no particular restrictions on the dispersant having a carboxyl group, and it can be appropriately selected depending on the purpose. Examples include dispersants containing structural units represented by general formula (2) and dispersants containing structural units represented by general formula (3).

[0028] [ka]

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

[0030] There are no particular restrictions on n in general formula (1), and it can be appropriately selected depending on the purpose. For example, it can be 10 to 500, and preferably 30 to 100. In general formula (2), there are no particular restrictions on m, and it can be appropriately selected depending on the purpose. For example, it can be between 10 and 500, and preferably between 30 and 100. In general formula (3), there are no particular restrictions on l, and it can be appropriately selected depending on the purpose. For example, it can be between 10 and 500, and preferably between 30 and 100.

[0031] There are no particular restrictions on the method for determining whether a dispersant contains structural units represented by general formulas (1) to (3), and a suitable method can be selected depending on the purpose. Examples include nuclear magnetic resonance (NMR) spectrometers and Fourier transform infrared spectroscopy (FT-IR). More specifically, it is possible to determine whether each structural unit is present by scraping off the insulating layer, immersing it in a tetrahydrofuran (THF) solvent, dissolving the resin components, and then performing analysis.

[0032] There are no particular restrictions on the molecular weight of the dispersant; it can be appropriately selected depending on the purpose. For example, the number-average molecular weight can be between 1,000 and 100,000. The dispersant has a number-average molecular weight of 1,000 or more, resulting in excellent dispersibility between insulating inorganic particles. The number-average molecular weight of the dispersant is 100,000 or less, resulting in excellent ejection performance for inkjet printing. There are no particular restrictions on the method for analyzing the molecular weight of a dispersant, and it can be appropriately selected depending on the purpose. For example, it can be measured by gel permeation chromatography (GPC, manufactured by Shimadzu Corporation).

[0033] There are no particular restrictions on the dispersant content in the insulating layer, and it can be appropriately selected depending on the purpose. However, it is preferably 0.5% to 5% by mass, and more preferably 1% to 3% by mass, relative to the total amount of insulating inorganic particles in the insulating layer. When the dispersant content is 0.5% by mass or more relative to the total amount of insulating inorganic particles in the insulating layer, sufficient dispersion effect of the insulating inorganic particles can be obtained, and the dispersed state can be maintained. Consequently, the ejection performance by inkjet printing can be improved. Furthermore, since the surface of the insulating inorganic particles is coated in the resulting insulating layer, it is possible to prevent them from falling out of the insulating layer. If the dispersant content is 5% by mass or less relative to the total amount of insulating inorganic particles in the insulating layer, thixotropy can be reduced. Furthermore, in the resulting insulating layer, problems such as the dispersant dissolving into the electrolyte and affecting battery performance can be eliminated.

[0034] As a dispersant, you may use one that you have synthesized as appropriate, or you may use a commercially available product. Examples of commercially available dispersants include Marialim® AAB-0851, Marialim AFB-1521, Marialim AKM-0531, Marialim AWS-0851, Marialim HKM-50A, Marialim SC-0708A, Marialim SC-0505K, Marialim SC-1015F (all manufactured by NOF Corporation), SN Dispersant 5020, SN Dispersant 5040, SN Dispersant 5468, Nopcospers 5600, Nopcosanto RFA (all manufactured by Sunnopco Corporation), and SCONA® TSPP 10213GB, TSPP 22113GA, TSIN 4013 GC, TSPOE 1002. Examples include GBLL, DISPER® BYK108, BYK-P105 (all manufactured by Big Chemie Co., Ltd.), Isoban®-04, Isoban-06, and Isoban-10 (manufactured by Kuraray Co., Ltd.).

[0035] <Binder> The binder for forming the insulating layer in the present invention preferably has a fluoroethylene group and a vinyl ether group. When a binder for forming an insulating layer contains only fluoroethylene groups, its solubility in the solvent tends to be low, and its thixotropy tends to be high. Furthermore, it is difficult to achieve a viscosity suitable for inkjet printing. Even when the viscosity is reduced by decreasing the concentration of solids in the liquid composition, there were concerns about unevenness after coating the substrate or an increase in the relative amount of liquid composition applied. In the present invention, if the binder for forming the insulating layer contains fluoroethylene groups and vinyl ether groups, its solubility in common solvents such as alcohol-based and ether-based solvents is improved, and consequently, its thixotropy decreases, resulting in a liquid composition that can be stably ejected by inkjet printing. Furthermore, in the resulting insulating layer, the inclusion of fluoroethylene groups in the binder for forming the insulating layer can improve battery stability. Thixotropy is the property of a highly viscous fluid in which its viscosity reversibly decreases when a force is applied to it.

[0036] There are no particular limitations on the method for determining whether the binder for forming the insulating layer in the present invention has fluoroethylene groups and vinyl ether groups, and a suitable method can be selected depending on the purpose. Examples include nuclear magnetic resonance (NMR) spectrometers and Fourier transform infrared spectroscopy (FT-IR). More specifically, the functional groups can be identified by scraping off the insulating layer, immersing it in a tetrahydrofuran (THF) solvent or the like to dissolve the resin components, and then performing an analysis.

[0037] The weight-average molecular weight (Mw) of the binder for forming the insulating layer in this invention is 25,000 or more and 80,000 or less. If the weight-average molecular weight (Mw) of the binder for forming the insulating layer is 25,000 or higher, the liquid composition can be made to have a viscosity suitable for inkjet ejection, and an insulating layer with sufficient strength can be obtained. Furthermore, the resulting insulating layer is preferable because it does not dissolve in the 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 decreases, making it possible to stably eject it by inkjet and obtain a uniform insulating layer.

[0038] There are no particular restrictions on the method for measuring the weight-average molecular weight (Mw) of the binder used to form the insulating layer; it can be appropriately selected depending on the purpose. For example, it can be measured by gel permeation chromatography (GPC). More specifically, the weight-average molecular weight of the binder used to form the insulating layer can be measured by scraping off the insulating layer, immersing it in a solvent such as tetrahydrofuran (THF) to dissolve the resin components, and then performing analysis.

[0039] There are no particular restrictions on the content of the binder for forming the insulating layer, and it can be appropriately selected according to the purpose, but it is preferable that it be 1% by mass or more and 5% by mass or less relative to the total amount of insulating inorganic particles in the insulating layer. If the content of the binder for forming the insulating layer is 1% by mass or more relative to the total amount of insulating inorganic particles in the insulating layer, an insulating layer with sufficient strength can be obtained. When the content of the binder for forming the insulating layer is 5% by mass or less relative to the total amount of insulating inorganic particles in the insulating layer, thixotropy can be reduced, improving ejection performance by inkjet printing and suppressing the occurrence of nozzle clogging and ejection abnormalities (ejection curves and abnormal ejection speeds). The resulting insulating layer is preferable because it does not suffer from problems such as a decrease in output due to increased battery resistance and a decrease in cycle characteristics. More specifically, if the content of the binder for forming the insulating layer is greater than 5% by mass, there is a concern that some of the binder may dissolve into the electrolyte, increasing battery resistance and reducing battery output, and it may also accelerate the deterioration of battery performance in cycle evaluation.

[0040] As a binder for forming the insulating layer, a suitable synthetic material may be used, or a commercially available product may be used. Examples of commercially available binders for forming insulating layers include Lumiflon® LF200F (manufactured by AGC Inc.), Zeffle® GK570 (manufactured by Daikin Corporation), and Zaflon® GF-X-101 and GF-400 (manufactured by Toagosei Co., Ltd.).

[0041] The dispersant and the binder for forming the insulating layer are soluble in a nonpolar solvent or a mixture containing a nonpolar solvent (mixed solvent). The solubility of the resin in a nonpolar solvent or a mixture containing a nonpolar solvent can be confirmed under conditions where the nonpolar solvent or the mixture containing a nonpolar solvent is in liquid form. For example, the solubility in a mixture containing a non-aqueous electrolyte solvent such as dimethyl carbonate, ethyl methyl carbonate, and a nonpolar solvent, as well as a polar solvent such as ethylene carbonate, can be confirmed by checking the solubility at 25°C and 1 atm. In this specification, a nonpolar solvent is defined as a solvent with a bond dipole moment of 1.15 D or less. The solubility of the resin in a nonpolar solvent or a mixture containing a nonpolar solvent is preferred from the viewpoint of improving the thixotropy of the liquid composition.

[0042] Examples of binders for forming insulating layers that dissolve in nonpolar solvents include Lumiflon® LF200F (manufactured by AGC Inc.), Zeffle® GK570 (manufactured by Daikin Corporation), and Zaflon® GF-X-101 and GF-400 (manufactured by Toagosei Co., Ltd.). Examples of binders for forming insulating layers that do not dissolve in nonpolar solvents include KF Polymer® #850, W#1100, W#9100 (manufactured by Kureha Corporation) and SOREF® 5130 (manufactured by Solvay Japan Ltd.), among others.

[0043] There are no particular restrictions on the ratio of dispersant to binder for forming the insulating layer (dispersant:binder for forming the insulating layer), and it can be appropriately selected according to the purpose, but a ratio of 3:1 to 3:15 is preferred. A ratio of 3:1 or higher between the dispersant and the binder for forming the insulating layer is preferable because the resulting insulating layer does not dissolve in the electrolyte. When the ratio of dispersant to insulating layer binder is 3:15 or less, the ejection performance by inkjet printing is 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 individually in a nonpolar solvent or a mixture containing a nonpolar solvent, combining the dispersant and the binder for forming the insulating layer in the above ratio makes it possible to form an insulating layer with excellent film strength after cycle testing.

[0044] <Solvent> The liquid composition for forming an insulating layer of the present invention may contain a solvent. As for the solvent, there are no particular restrictions as long as it can disperse insulating inorganic particles, and it can be appropriately selected according to the purpose. Examples include water, hydrocarbon solvents, alcohol solvents, ketone solvents, ester solvents, and ether solvents. Specific examples of solvents 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 individually or in combination of two or more.

[0045] There are no particular restrictions on the solvent content, and it can be appropriately selected depending on the purpose. For example, it can be 40% by mass or more and 70% by mass or less of the total volume of the liquid composition.

[0046] <Other ingredients> The liquid composition for forming an insulating layer of the present invention may also contain additives such as surfactants, pH adjusters, rust inhibitors, preservatives, fungicides, antioxidants, reduction inhibitors, evaporation accelerators, and chelating agents as other components. There are no particular restrictions on the content of other components, and they can be set as appropriate depending on the content of various components in the liquid composition.

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

[0048] In the liquid composition for forming an insulating layer of the present invention, when viscosity A is the viscosity measured using an e-type viscometer at 100 rpm and viscosity B is the viscosity measured using an e-type viscometer at 10 rpm, 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 between 0.95 and 1.05, ejection failures do not occur even during continuous inkjet printing, and stable ejection is possible. Furthermore, problems such as nozzle clogging and ejection failures during continuous ejection caused by ejection deviations or abnormal ejection speeds can be eliminated.

[0049] There are no particular limitations on the method for measuring the viscosity of the insulating layer-forming liquid composition of the present invention, and a suitable method can be selected depending on the purpose. For example, it can be measured using an e-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.) with a standard rotor of 1°34'×R24.

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

[0051] <Method for producing a liquid composition for forming an insulating layer> There are no particular limitations on the method for producing the insulating layer-forming liquid composition of the present invention, and can be appropriately selected depending on the purpose. For example, it can be obtained by adding solvent B, in which an insulating layer-forming binder and other components are dissolved, to a dispersion in solvent A in which insulating inorganic particles and a dispersant are dispersed. Solvents A and B may be the same or different. The dispersion may be prepared by pre-mixing the solvent, insulating inorganic particles, and dispersant, followed by use in a disperser. There are no particular restrictions on the disperser, and one can be appropriately selected depending on the purpose. Examples include homomixers, homogenizers, ultrasonic dispersers, ball mills, bead mills, and cavitation mills.

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

[0053] [ka]

[0054] [ka]

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

[0056] Herein, one embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited in any way to these embodiments. In addition, the same reference numerals are used for identical components in each drawing, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to this embodiment, and can be set to a number, position, shape, etc. that is preferable for carrying out the present invention.

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

[0058] <Base> As for the substrate, there are no particular restrictions as long as it has electronic conductivity and is stable to the applied potential, and it can be appropriately selected according to the purpose. Examples include aluminum foil, copper foil, stainless steel foil, titanium foil, etched foil obtained by etching these materials to create fine holes, carbon-coated foil obtained by coating the surface with a carbon-containing resin layer, and perforated substrates used in lithium-ion capacitors.

[0059] <Electrode composite layer> The electrode composite layer is provided on a portion of the substrate. In other words, the electrode composite layer is formed such that there are exposed portions of the substrate where the electrode composite layer is not provided, for the purpose of providing an insulating layer or welding leads. The electrode composite layer (sometimes referred to as the "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 active material content is 70% by mass or more of the total electrode composite layer.

[0060] There are no particular restrictions on the electrode composite layer, and it can be appropriately selected according to the purpose. For example, it may contain an active material (negative electrode active material or positive electrode active material), and may optionally contain a conductive additive, a binder for the electrode composite layer, a dispersant for the electrode composite layer, a solid electrolyte, and other components.

[0061] [Figures 2A-2B] Here, Figure 2A is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. Figure 2B is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. The electrode composite layer may have an opening 21 as shown in Figure 2A. The number of openings 21 is preferably one or more, and more preferably multiple. The opening 21 may penetrate the electrode composite layer from the surface of the electrode composite layer to the surface of the substrate, or it may not penetrate to the surface of the substrate. The opening 21 may be a cavity or may be filled with material 22. If the opening 21 is filled with material 22, the material 22 may be a single material or a mixture of two or more materials, but in either case, the material is different from the material constituting the electrode composite layer. From the viewpoint of improving ionic conductivity, the material 22 is preferably a material having a solid electrolyte. Since the electrode composite layer having the opening 21 is easy to control during application, it can be suitably manufactured by using an inkjet as the means for forming the electrode composite layer.

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

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

[0064] -Cathode active material- As the positive electrode active material, there are no particular restrictions as long as it is a material that can reversibly intercept and release alkali metal ions, but 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 cobaltate, lithium nickelate, and lithium manganeseate.

[0065] As alkali metal-containing transition metal compounds, polyanionic compounds having an XO4 tetrahedron (X=P, S, As, Mo, W, Si, etc.) in their 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 power characteristics. Furthermore, when using polyanionic compounds, it is preferable that the surface is coated with a conductive additive such as a carbon material to form a composite, in terms of electronic conductivity.

[0066] It is preferable that the alkali metal-containing transition metal compound has at least a portion of its surface coated with an ion-conducting oxide. Lithium ion-conducting oxide is preferred as the ion-conducting oxide. There are no particular restrictions on lithium-ion conductive oxides, and they can be appropriately selected according to the purpose. For example, oxides represented by the general formula LixAOy (where 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) can be cited. Specific examples of lithium-ion conductive oxides include Li3BO3, LiBO2, Li2CO3, LiAlO2, Li4SiO4, Li2SiO3, Li3PO4, Li2SO4, Li2TiO3, Li4Ti5O12, Li2Ti2O5, Li2ZrO3, LiNbO3, LiTaO3, Li2MoO4, and Li2WO4. Among these, Li4Ti5O12, Li2ZrO3, or LiNbO3 are preferred. Furthermore, the lithium-ion conductive oxide may be a composite oxide. Any combination of lithium-ion conductive oxides can be used as the composite oxide, for example, 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 intercept and release alkali metal ions, and can be appropriately selected according to 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, hard carbon (difficult to graphitize), and soft carbon (easily graphitizable). Other materials besides carbon include, for example, lithium titanate and titanium oxide. From the viewpoint of increasing the energy density of lithium-ion batteries, high-capacity materials such as silicon, tin, silicon alloys, tin alloys, silicon oxide, silicon nitride, and tin oxide can also be suitably used as negative electrode active materials.

[0068] <<Conductive additive>> There are no particular restrictions on the conductive additive, and it can be appropriately selected depending on the purpose. For example, carbon black produced by the furnace method, acetylene method, gasification method, etc., or carbon materials such as carbon nanofibers, carbon nanotubes, graphene, and graphite particles can be used. Other conductive additives besides carbon materials include, for example, metal particles such as aluminum, metal fibers, etc. The conductive additive may also be pre-compounded with the active material.

[0069] There are no particular restrictions on the content of the conductive additive relative to the active material, and it can be set appropriately depending on the purpose, but it is preferably 10% by mass or less, and more preferably 8% by mass or less. A concentration of 10% by mass or less of the conductive additive relative to the active material is preferable because it improves the stability of the liquid composition for forming the electrode composite layer. A concentration of 8% by mass or less of the conductive additive relative to the active material is preferable because it further improves the stability of the liquid composition for forming the electrode composite layer.

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

[0071] A polymer compound can be used as the binder for the electrode composite layer. Examples of polymer compounds include polyvinylidene fluoride (PVDF), acrylic resins, polyethylene, polypropylene, polyurethane, nylon, polytetrafluoroethylene, polyphenylene sulfide, polyethylene tephthalate, polybutylene tephthalate and other thermoplastic resins, polyamide compounds, polyimide compounds, polyamide-imides, ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), nitrile butadiene rubber (NBR), isoprene rubber, polyisobutene, polyethylene glycol (PEO), polymethylmecryl acid (PMMA), and polyethylene vinyl acetate (PEVA).

[0072] There are no particular restrictions on the content of the electrode composite layer binder relative to the active material, and it can be set appropriately according to the purpose, but it 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. When the content of the electrode composite layer binder relative to the active material is 1% by mass or more, the active material can be firmly bound to the substrate, which is preferable.

[0073] <<Dispersant for electrode composite layer>> As a dispersant for the electrode composite layer, there are no particular limitations as long as it can improve the dispersibility of the active material in the liquid composition for forming the electrode composite layer. Examples include polymeric dispersants such as polyethylene oxide, polypropylene oxide, polycarboxylic acid, naphthalene sulfonic acid formalin condensate, polyethylene glycol, polycarboxylic acid partial alkyl ester, polyether, and polyalkylene polyamine; low molecular weight dispersants such as alkyl sulfonic acid, quaternary ammonium higher alcohol alkylene oxide, polyhydric alcohol ester, and alkyl polyamine; and inorganic dispersants such as polyphosphate dispersants. In this specification, a distinction is made between "dispersant having a carboxyl group or an acid anhydride group" in a liquid composition for forming an insulating layer and "dispersant for electrode composite layer" in a liquid composition for forming an electrode composite layer.

[0074] <<Solid electrolyte>> As a solid electrolyte, there are no particular restrictions as long as it is a solid material that has electronic insulating properties and exhibits ionic conductivity. However, from the viewpoint of having high ionic conductivity, sulfide solid electrolytes and oxide-based solid electrolytes are preferred.

[0075] Examples of sulfide solid electrolytes include Li10GeP2S12 and Li6PS5X (X=F, Cl, Br, I), which has an argyrodite crystal structure. Examples of oxide-based solid electrolytes include LLZ (Li7La3Zr2O12) with a garnet-type crystal structure, LATP (Li1+xAlxTi20x(PO4)3) (0.1≦x≦0.4) with a NASICON-type crystal structure, LLT (Li0.33La0.55TiO3) with a perovskite-type crystal structure, and amorphous LIPON (Li2.9PO3.3N0.4). These solid electrolytes may be used individually or in combination of two or more types.

[0076] When the electrode composite layer is a positive electrode composite layer, there are no particular restrictions on the average thickness of the positive electrode composite layer, and it can be appropriately selected according to the purpose, but it 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 composite layer is 10 μm or more, the energy density of the electrochemical element improves. When the average thickness of the negative electrode composite layer is 300 μm or less, the load characteristics of the electrochemical element are improved.

[0077] When the electrode composite layer is the negative electrode composite layer, there are no particular restrictions on the average thickness of the negative electrode composite layer, and it can be appropriately selected according to the purpose, but it 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 composite layer is 10 μm or more, the energy density of the electrochemical element improves. When the average thickness of the negative electrode composite layer is 450 μm or less, the cycle characteristics of the electrochemical element are improved.

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

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

[0080] [Figures 3A-3B] Here, Figure 3A is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. Figure 3B is a schematic cross-sectional view showing an electrode according to another embodiment of the present invention. As shown in Figure 3A, the insulating layer 3 may be provided at the boundary and at the end of the electrode composite layer 2. As shown in Figure 3B, the insulating layer 3 may be provided at the boundary and on the upper surface of the electrode composite layer 2. When the insulating layer 3 is provided on the upper surface of the electrode composite layer 2, the coverage rate of the upper surface of the electrode composite 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 composite layer 2, there may be exposed areas on the upper surface of the electrode composite layer 2 that are not covered by the insulating layer 3. By providing the insulating layer 3 on the electrode composite layer 2, when coating by inkjet, the insulating layer can be produced with low film thickness and uniformity, thereby improving the stability of the battery.

[0081] There are no particular restrictions on the average thickness of the insulating layer, and it can be appropriately selected according to the purpose, but it is preferably 2 μm to 20 μm, and more preferably 5 μm to 10 μm. A minimum average thickness of 2 μm for the insulating layer is preferable because it provides sufficient insulation. When the average thickness of the insulating layer is 20 μm or less, problems such as the electrode composite layer being damaged by the weight of the liquid composition itself, the liquid composition flowing and causing unevenness, or seeping into the substrate can be eliminated when applying the liquid composition.

[0082] There are no particular restrictions on the method for measuring the average thickness of the insulating layer; it can be appropriately selected depending on the purpose. For example, it can be measured using a digital micrometer (manufactured by Mitutoyo Corporation).

[0083] There are no particular restrictions on the peel strength of the insulating layer against the substrate, and it can be appropriately selected according to the purpose, but it is preferably 50 N / m or more. If the peel strength of the insulating layer against the substrate is 50 N / m or higher, it is possible to prevent some of the insulating inorganic particles contained in the insulating layer from falling off due to friction during electrode formation using the roll-to-roll method or during transportation. This also prevents any impact on battery characteristics.

[0084] There are no particular restrictions on the method for measuring the peel strength of the insulating layer relative to the substrate; it can be appropriately selected depending on the purpose. One example is shown below. [Method for measuring peel strength] The evaluation device used is, for example, a light-load type adhesive / film peel analysis device (VPA-3S, manufactured by Kyowa Interface Science Co., Ltd.), and an 8mm wide tape (cellophane tape, manufactured by Nitto Co., Ltd.) is used. The tape is attached to an insulating layer, and when peeling is performed at a peeling angle of 90 degrees and a speed of 30 mm / min, the load applied to the load cell is defined as the peel strength.

[0085] There are no particular restrictions on the width of the insulating layer, and it can be appropriately selected depending on the battery configuration, but it is preferable that it be between 2 mm and 30 mm. The "width" of the insulating layer refers to the distance from one end to the other (in the longitudinal direction of the electrode) of the upper surface of the insulating layer facing the substrate surface in contact with the electrode composite layer, in a cross-sectional view obtained by cutting the electrode in the thickness direction and parallel to the length direction of the electrode. If the width of the insulating layer is 2 mm or more, it becomes difficult to follow the meandering of the electrode composite layer, and problems such as being unable to cover the exposed substrate with the insulating layer can be resolved. If the width of the insulating layer is 30 mm or less, problems such as interference with lead welding and excessive battery size relative to battery capacity can be resolved.

[0086] There are no particular restrictions on the width of the insulating layer covering the electrode composite layer, and it can be appropriately selected according to the purpose, but it is preferably 0.1 mm or more and 5 mm or less. In this specification, "cover width" refers to the distance from one end to the other (in the longitudinal direction of the electrode) on the surface that is in contact with the electrode composite layer and the insulating layer, in a cross-sectional view obtained by cutting the electrode in the thickness direction and parallel to the length direction of the electrode. If the coverage width is 0.1 mm or more, it becomes difficult to follow the meandering of the electrode composite layer, and problems such as being unable to cover the exposed substrate with an insulating layer can be resolved. If the overlap width is 5 mm or less, it is possible to prevent the insulating layer from negatively affecting the battery capacity.

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

[0088] There are no particular restrictions on the adhesive, and it can be appropriately selected according to the purpose, but it is preferable that it be at least one of acrylate and PVDF (polyvinylidene fluoride).

[0089] The adhesive may be applied by an inkjet method, from the viewpoint of being able to be applied precisely and to the desired shape.

[0090] (Electrode manufacturing equipment) The electrode manufacturing apparatus of the present invention comprises a containment container and means for applying a liquid composition for forming an insulating layer, and may optionally also comprise means for forming an electrode composite layer, means for heating the liquid composition for forming an insulating layer, and other means. The method for manufacturing an electrode according to the present invention may include an electrode composite layer formation step, an insulating layer formation step, and other steps.

[0091] <container> The containment container comprises a liquid composition for forming an insulating layer and a container, wherein the liquid composition for forming an insulating layer is contained within the container. Examples of containers include glass bottles, plastic containers, plastic bottles, stainless steel bottles, 18-liter cans, and drums.

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

[0093] <<Step for applying liquid composition for electrode composite layer formation, and means for applying liquid composition for electrode composite layer formation>> The step of applying the liquid composition for electrode composite layer formation is a step of applying the liquid composition for electrode composite layer formation to a part of the substrate. The means for applying the liquid composition for electrode composite layer formation is a means for applying the liquid composition for electrode composite layer formation to a part of the substrate. The step of applying the liquid composition for electrode composite layer formation can be suitably carried out by means of applying the liquid composition for electrode composite layer formation.

[0094] When manufacturing a positive electrode, a liquid composition for forming an electrode composite layer (liquid composition for forming a positive electrode composite layer) is applied to a portion of the positive electrode substrate to form a positive electrode composite layer. When manufacturing a negative electrode, a liquid composition for forming an electrode composite layer (liquid composition for forming a negative electrode composite layer) is applied to a portion of the negative electrode substrate to form a negative electrode composite layer.

[0095] There are no particular limitations on the means for applying the liquid composition for electrode composite layer formation, and it can be appropriately selected according to the purpose. Examples include the comma coater method, die coater method, curtain coat method, spray coat method, and liquid ejection method (inkjet method, IJ method).

[0096] <<Heatment process for the liquid composition for forming the electrode composite layer, and means for heating the liquid composition for forming the electrode composite layer>> The step of heating the liquid composition for electrode composite layer formation is a step of heating the liquid composition for electrode composite layer formation that has been applied to the substrate. The means for heating the liquid composition for forming the electrode composite layer is a means for heating the liquid composition for forming the electrode composite layer that has been applied to a substrate. The step of heating the liquid composition for forming the electrode composite layer can be suitably carried out by a means for heating the liquid composition for forming the electrode composite layer.

[0097] There are no particular limitations on the heating means (process) for the liquid composition for forming the electrode composite layer, and can be appropriately selected according to the purpose. Examples include heating the coated surface with a resistance heater, infrared heater, fan heater, etc., or drying the coated surface from the back side with a hot plate, drum heater, etc. From the viewpoint of uniformly heating and drying the coated surface, resistance heaters, infrared heaters, and fan heaters that can dry the coated surface without contact are preferred. These heating mechanisms may be used individually or in combination of two or more.

[0098] There are no particular restrictions on the heating temperature in the heating step of the liquid composition for forming the electrode composite layer, and it can be appropriately selected according to the purpose. However, from the viewpoint of protecting the substrate and the active material of the electrode composite layer, it is preferable that the temperature be between 70°C and 150°C.

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

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

[0101] As a means of applying the liquid composition for forming the insulating layer, a liquid ejection method such as an inkjet method that can be applied non-contact and on demand is preferred.

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

[0103] There are no particular limitations on the heating means (process) for the liquid composition for forming the insulating layer, and can be appropriately selected according to the purpose. Examples include heating the coated surface with a resistance heater, infrared heater, fan heater, etc., or drying the coated surface from the back side with a hot plate, drum heater, etc. From the viewpoint of uniformly heating and drying the coated surface, resistance heaters, infrared heaters, and fan heaters that can dry the coated surface without contact are preferred. These heating mechanisms may be used individually or in combination of two or more.

[0104] There are no particular restrictions on the heating temperature in the heating step of the liquid composition for forming the insulating layer, and it can be appropriately selected according to the purpose. However, from the viewpoint of protecting the active material of the substrate and electrode composite layer, it is preferable that the temperature be between 70°C and 150°C. A heating temperature of 70°C or higher in the heating step of the liquid composition for forming the insulating layer is preferable because it improves the strength of the insulating layer. It is preferable that the heating temperature in the heating step of the liquid composition for forming the insulating layer is 150°C or lower, as this prevents bubbles from bumping on the surface of the insulating layer.

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

[0106] Here, one embodiment of the electrode manufacturing apparatus according to the present invention will be described with reference to the drawings. However, the present invention is not limited in any way to these embodiments. In addition, the same reference numerals are used for identical components in each drawing, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to this embodiment, and can be set to a number, position, shape, etc. that is preferable for carrying out the present invention.

[0107] [Figure 4] Figure 4 is a schematic diagram showing an electrode manufacturing apparatus according to one embodiment of the present invention. The liquid dispensing device 300 shown in Figure 4 dispenses an insulating layer-forming liquid composition 130A onto an electrode element 140, which has a negative electrode composite layer 120 provided on a negative electrode substrate 110. The insulating layer-forming liquid composition 130A is stored in a tank 307 and supplied from the tank 307 to the liquid dispensing head 306 via a tube 308.

[0108] The liquid dispensing device 300 may be provided with a mechanism to cap the nozzle of the liquid dispensing head 306 in order to prevent drying when the insulating layer forming liquid composition 130A is not being dispensed from the liquid dispensing head 306.

[0109] When manufacturing the negative electrode, the electrode element 140 is placed on a heating stage 200, and then droplets of the insulating layer forming liquid composition 130A are dispensed onto the electrode element 140 and then heated. At this time, the stage 200 may move, and the liquid dispensing head 306 may also move. When heating the insulating layer-forming liquid composition 130A discharged onto the electrode element 140, 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, but from the standpoint of power consumption, it is preferably in the range of 70°C to 150°C. When heating the insulating layer-forming liquid composition 130A discharged onto the electrode element 140, ultraviolet light may be irradiated. This results in an electrode (negative electrode) 400 in which an insulating layer 130 is formed on the electrode element 140.

[0111] In this embodiment, an example is shown in which an insulating layer 130 is formed on an electrode element 140 in which a negative electrode composite layer 120 is pre-provided on a 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 is formed on a negative electrode substrate 110, using the same line as the apparatus shown in Figure 4.

[0112] [Figure 5] Figure 5 is a schematic diagram showing an electrochemical element according to one embodiment of the present invention. Figure 5 shows an electrochemical element 700 in which a positive electrode 500, on which a positive electrode composite layer 501 and an insulating layer 13 are provided on a positive electrode substrate 501, and a negative electrode 400, on which a negative electrode composite layer 402 and an insulating layer 13 are provided on a negative electrode substrate 401, are arranged as opposing electrodes via a separator 600. Alternatively, a processing solution 7 (a solution containing a non-aqueous solvent and an electrolyte) is placed in a liquid bath 6, and the electrochemical element 700 is immersed in it. 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 on both.

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

[0114] There are no particular restrictions on the number of electrochemical elements 700 mounted on the mounted product, and they can be appropriately selected according to the purpose, but it is preferable to have multiple elements. In a mounted product that has multiple electrochemical elements 700, it is preferable that at least two electrochemical elements 700 are bonded in an L-shape and arranged on the substrate of the mounted product. It is preferable that the bonding regions of at least two electrochemical elements 700 and the bonding regions where the electrochemical elements 700 and the mounted product are bonded together with an adhesive do not overlap.

[0115] There are no particular restrictions on the adhesive used; it can be selected appropriately depending on the purpose.

[0116] The mounted components may have other components different from the electrochemical element 700 in areas different from the area to which the electrochemical element 700 is bonded. There are no particular restrictions on the other components, and they can be appropriately selected according to the purpose. Examples include heat dissipation components such as heat dissipation fans and heat dissipation pipes.

[0117] The mounted component and other components may be bonded together with adhesive. For example, if the mounted component and other components are fixed together with screws, there is a risk that the fixing position may change due to the loosening of the screws. By bonding them together with adhesive, the electrochemical element and the heat dissipation component can be fixed in place and are also resistant to vibration, so that the heat generated when the mounted component (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 and other components onto the mounted product, the adhesive may be applied by an inkjet method, from the viewpoint of being able to apply it precisely and in the desired shape. When applying the adhesive by an inkjet method, from the viewpoint of productivity, it is preferable to apply the adhesive to the bonding area between the electrochemical element 700 and the mounted product, and to the bonding area between other components and the mounted product, in a single scan of the inkjet head.

[0119] (Energy storage device) The energy storage device of the present invention comprises electrodes. Since electrodes similar to those described in the (Electrodes) section of this specification can be used, redundant explanations are omitted.

[0120] Here, an embodiment of the energy storage device according to the present invention will be described with reference to the drawings. However, the present invention is not limited in any way to these embodiments. In addition, the same reference numerals are used for identical components in each drawing, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the components are not limited to this embodiment, and can be set to a number, position, shape, etc. that is preferable for carrying out the present invention.

[0121] [Figure 6] Figure 6 is a schematic diagram showing an energy storage device according to one embodiment of the present invention. The energy storage device 800 has an electrolyte layer 51 made of a non-aqueous electrolyte formed on a stacked electrode 40, and is sealed by an outer casing 52. In the energy storage device 800, the lead wires 41 and 42 are led out to the outside of the outer casing 52. The stacked electrode 40 consists of a negative electrode 400 and a positive electrode 500 stacked with a separator 600 in between. Here, the positive electrode 500 is stacked on both sides of the negative electrode 400. In addition, a leader wire 41 is connected to the negative electrode substrate 401, and a leader wire 42 is connected to the positive electrode substrate 501. The negative electrode 400 has a negative electrode composite layer 402 and an insulating layer 13 sequentially formed on both sides of the negative electrode substrate 401. The positive electrode 500 has a positive electrode composite layer 502 and an insulating layer 13 sequentially formed on both sides of the positive electrode substrate 501. Furthermore, the number of negative electrodes 400 and 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 on both.

[0122] There are no particular restrictions on the shape of the energy storage device using electrodes. Examples include a laminate type with stacked flat electrodes, a cylinder type with spirally arranged sheet electrodes and separators, a cylinder type with an inside-out structure combining pellet electrodes and separators, and a coin type with stacked pellet electrodes and separators. The energy storage device 800 may have other components as needed.

[0123] <<Non-aqueous electrolytes>> As a non-aqueous electrolyte, for example, a non-aqueous electrolyte solution can be used. Here, a non-aqueous electrolyte solution is an electrolyte solution in which the electrolyte salt is dissolved in a non-aqueous solvent. There are no particular restrictions on the non-aqueous solvent used in the non-aqueous electrolyte; it can be appropriately selected according to the purpose, for example, aprotic organic solvents. As for the electrolyte salt, there are no particular restrictions as long as it has high ionic conductivity and can be dissolved in a non-aqueous solvent. Examples of cations that make up electrolyte salts include lithium ions. There are no particular restrictions on the anions that make up the alkali metal salt, and they can be appropriately selected depending on the purpose, but it is preferable that they contain halogen atoms. Specific examples include BF4-, PF6-, AsF6-, CF3SO3-, (CF3SO2)2N-, and (C2F5SO2)2N-. There are no particular restrictions on the alkali metal salts, and they can be appropriately selected depending on the purpose. Examples include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoride arsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide. These may be used individually or in combination of two or more types. The concentration of the electrolyte salt in the non-aqueous electrolyte is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably between 1 mol / L and 4 mol / L.

[0124] <<Separator>> The separator 600 is placed between the negative electrode 400 and the positive electrode 500 as needed to prevent a short circuit between the negative electrode 400 and the positive electrode 500. A separator is a porous membrane with connecting pores that insulates and separates the positive and negative electrodes, for example, in electrochemical elements such as secondary batteries. There are no particular restrictions on the separator, and it can be appropriately selected according to the purpose. Examples include paper such as kraft paper, vinylon blended paper, and synthetic pulp blended paper, cellophane, polyethylene graft membranes, polyolefin nonwovens such as polypropylene meltblown nonwovens, polyamide nonwovens, glass fiber nonwovens, and micropore membranes. There are no particular restrictions on the size of the separator, as long as it can be used in the electrochemical element. The separator may have a single-layer structure or a multi-layer structure. Furthermore, if a solid electrolyte is used as the non-aqueous electrolyte, the separator 600 can be omitted.

[0125] There are no particular restrictions on the applications of energy storage devices, and they can be appropriately selected according to the purpose. Examples include laptop computers, smart devices, e-book players, portable fax machines, portable copiers, portable printers, headphone stereos, video cameras, LCD TVs, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, lighting fixtures, toys, game consoles, clocks, strobes, and cameras. As described above, the energy storage device of this embodiment provides the same effects as the electrodes of this embodiment by having the electrodes of this embodiment. [Examples]

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

[0127] (Example 1) <Preparation of liquid composition for forming an insulating layer> A pre-dispersion was prepared by mixing 45.0 parts by mass of LS-711CB (α-alumina, manufactured by Nippon Light Metal Co., Ltd.) as insulating inorganic particles, 1.35 parts by mass of GK570 (manufactured by Daikin Corporation) as an insulating layer binder, 1.35 parts by mass of AKM0531 (manufactured by NOF Corporation) as a dispersant, and 52.3 parts by mass of ethyl lactate as a dispersion medium. This pre-dispersion was placed in a glass ball mill pot along with 5 mmΦ zirconium beads, and the sealed pot was placed on a mill turntable to disperse the mixture and 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] <Fabrication of the negative electrode> A liquid composition for forming a negative electrode composite layer was prepared by mixing 97 parts of graphite (manufactured by JFE Chemical Corporation, model number BTM-DMP), 1 part by mass of a thickening agent (carboxymethylcellulose, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., model number Selogen HS-6), 2 parts by mass of a polymer (acrylic resin, manufactured by Nippon Zeon Corporation, model number AZ-9129), and 100 parts by mass of water as a solvent. A 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 negative electrode with a negative electrode composite layer formed on both sides, with a coating amount per unit area (area density) of 9 mg / cm2 on each side. The thickness of the negative electrode at this time was 216 μm, and the volume density of the negative electrode was 0.91 g / cm3. Next, the negative electrode was pressed in a roll press machine until its volume density was 1.6 g / cm³ to obtain the negative electrode to be used.

[0129] <Fabrication of the positive electrode> 93 parts by mass of lithium nickel-cobalt manganate (NCM622, manufactured by Beijing Dangben Co., Ltd.) was prepared as the positive electrode active material, 3 parts by mass of a conductive additive (Ketjenbrak, manufactured by Lion Specialty Chemicals, model no. 600JD), and 4 parts by mass of PVDF (polyvinylidene fluoride, manufactured by Solvay, model no. Solev5130) was prepared as a binder for the electrode composite layer. These were dispersed in N-methylpyrrolidone (NMP) (manufactured by Mitsubishi Chemical Corporation) to prepare a slurry. This slurry was applied to an aluminum (manufactured by UACJ Corporation, model no. 1N30) positive electrode substrate and dried to obtain a positive electrode with a positive electrode composite layer formed on both sides with a coating amount per unit area (area density) of 15.0 mg / cm2. Next, the positive electrode was compressed and molded using a roll press machine to a volume density of 3.4 g / cm3 to form the positive electrode.

[0130] <Formation of insulating layer> The insulating layer-forming liquid composition was printed along the boundary between the exposed positive electrode substrate and the positive electrode composite layer, with a width of 10 mm, an overlap width of 1 mm, and a film thickness of 5 μm at the exposed positive electrode substrate. An inkjet head (Ricoh MH2420) was used for printing.

[0131] <Fabrication of electrochemical elements> The fabricated positive and negative electrodes were alternately stacked via a film separator (Toray Industries, Inc., model number F20BHE) to form an electrode element consisting of three positive electrodes and four negative electrodes. The uncoated portions of the electrodes were bundled together, and nickel tabs serving as negative electrode lead wires were welded to the negative electrodes, while aluminum tabs serving as positive electrode lead wires were welded to the positive electrodes. This electrode element was then impregnated with a 1.5M LiPF6 non-aqueous electrolyte in an EC:DMC:EMC ratio of 1:1:1, sealed in an aluminum laminate film, and a lithium-ion secondary battery was fabricated as an electrochemical element.

[0132] (Examples 2-30, Comparative Examples 1-6) Except for changing the composition of the liquid composition for forming the insulating layer as shown in Tables 1 to 6, the liquid composition for forming the insulating layer and the lithium-ion secondary battery were prepared in the same manner as in Example 1.

[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 Inc.) • 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 Vivoval 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 Inc.) ·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 (manufactured by NOF Corporation) • SC0505K (manufactured by NOF Corporation) • Isoban-10 (manufactured by Kuraray Co., Ltd.) • HKM-50A (manufactured by NOF Corporation) • DISPERBY K-108 (manufactured by Big Chemie) • DISPERBYK2000 (manufactured by Big Chemie) • SN Dispersant 9228 (manufactured by Sanopco Corporation)

[0136] -Insulating inorganic particles- • LS-711CB (manufactured by Nippon Light Metal Co., Ltd.) • CT-3000LSSG (manufactured by Almatis) • SEPal-60 (manufactured by Alteo) • AKP-3000 (manufactured by Sumitomo Chemical Co., Ltd.) • BMB-07 (manufactured by Kawai Coal Industries Co., Ltd.) • F-10 (manufactured by Showa Denko Corporation) • TZ-3YS (manufactured by Tosoh Corporation) • AA07 (manufactured by Sumitomo Chemical Co., Ltd.) • AA1.5 (manufactured by 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 instrument, GPC-8020 (Tosoh Corporation), was connected to columns TSK G2000HXL and G4000HXL (Tosoh Corporation). After setting the column temperature to 40°C, tetrahydrofuran containing the stabilizer BHT (Fujifilm Wako Pure Chemical Industries, Ltd.) was passed through the column at a flow rate of 1.0 mL / min. The same solvent used in the instrument was used to prepare the measurement sample, which was prepared to a resin concentration of 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 created using a monodisperse polystyrene standard sample (Tosoh Corporation).

[0138] <Evaluation of thixotropy of liquid compositions for forming insulating layers> The thixotropy of each insulating layer-forming liquid composition was evaluated using an e-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.). Using a standard rotor of 1°34'×R24, viscosity A was determined from the viscosity measured at a rotational speed of 100 rpm, and viscosity B was determined from the viscosity measured at a rotational speed of 10 rpm. The ratio of viscosity B to viscosity A [B / A] was calculated and evaluated. The sample size was 2, and the average value was used. A score of "△" or higher was considered acceptable. [Evaluation Criteria] ○: The ratio [B / A] is between 0.95 and 1.05. △: The ratio [B / A] is 0.8 or greater than or equal to less than 0.95, or greater than 1.05 and less than or equal to 1.2. ×: The ratio [B / A] is less than 0.8 or greater than 1.2.

[0139] <Evaluation of Discharge Performance of Insulating Layer Forming Liquid Composition> The ejection performance of each insulating layer-forming liquid composition was evaluated using an inkjet head (Ricoh MH2420). A score of "△" or higher was considered acceptable. [Evaluation Criteria] ○: Discharge was possible from all nozzles continuously for 10 minutes. △: Although some nozzles exhibited discharge abnormalities such as misaligned discharge or poor discharge speed, all nozzles were capable of dispensing. ×: Some nozzles failed to dispense fluid.

[0140] <Evaluation of continuous dispensing performance of liquid compositions for forming insulating layers> For each insulating layer-forming liquid composition, continuous ejection was performed for 30 minutes using an inkjet head (Ricoh MH2420), and the ejection state was compared after 1 minute and 30 minutes. A score of "△" or higher was considered acceptable. [Evaluation Criteria] 〇: After 30 minutes of continuous dispensing, there was no change in the dispensing state. △: After 30 minutes of continuous dispensing, some nozzles exhibited dispensing abnormalities such as misaligned discharge or poor discharge speed, but all nozzles were capable of dispensing. ×: After 30 minutes of continuous dispensing, some nozzles are failing to dispense.

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

[0142] <Evaluation of strength (before cycle testing)> Peel strength was evaluated using a positive electrode with an insulating layer formed on it. The evaluation device used was a light-load type adhesive / film peel analysis device (VPA-3S, Kyowa Interface Science Co., Ltd.), and an 8mm wide tape (Nitto Co., Ltd., cellophane tape) was used. The tape was attached to the insulating layer, and when the peeling operation was performed at a peeling angle of 90 degrees and a speed of 30 mm / min, the average value of the load applied to the load cell was read and the strength was evaluated. [Evaluation Criteria] ○: Peel strength of 50 N / m or more ×: Peel strength less than 50 N / m

[0143] <Evaluation of strength (after cycle testing)> The positive and negative lead wires of each lithium-ion secondary battery were connected to a charge / discharge test device (Hokuto Denko Co., Ltd., model number HJ0610SD8Y), and charged at a constant current and voltage of 4.2V and a current rate of 0.2C for 5 hours. After charging was complete, the batteries were left to stand in a 40°C constant temperature bath for 5 days. Subsequently, they were discharged at a constant current of 0.2C down to 2.5V. Then, they were charged at a constant current and voltage of 4.2V and a current rate of 0.2C for 5 hours, with a 10-minute pause in between, and discharged at a constant current of 0.2C down to 2.5V. The discharge capacity at this time was defined as the initial capacity. In this evaluation, cells with a discharge capacity within the range of 180mAh ± 1.8mAh were used. Using the initial capacity as the reference for full charge, a cycle test was performed 300 times, in which the battery was fully charged from a discharged state to a voltage of 4.2V at current rate C, and then discharged to 2.5V at current rate 2C. The cycle test was conducted in an ESPEC constant temperature chamber at a test environment of 45°C. After the cycle test, the sample was disassembled, the positive electrode was removed, lightly washed with dimethyl carbonate (DMC), and then the remaining state of the insulating layer at the boundary was checked. [Evaluation Criteria] ○: The insulating layer remains, and more than 90% of the print width at the time of printing is maintained. ×: The insulating layer is partially peeled off, and less than 90% of the print width remains compared to the print width during printing.

[0144] [Table 1]

[0145] [Table 2]

[0146] [Table 3]

[0147] [Table 4]

[0148] [Table 5]

[0149] [Table 6]

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

[0151] The results from Comparative Examples 1 to 4 show that when the binder has fluoroethylene groups and vinyl ether groups, and its weight-average molecular weight is between 25,000 and 80,000, an insulating layer with excellent discharge properties, continuous discharge properties, and redispersibility, as well as superior strength, can be obtained. The results from Comparative Examples 5 and 6 show that by having a carboxyl group or an acid anhydride group in the dispersant, it is possible to obtain an insulating layer with excellent discharge properties, continuous discharge properties, and redispersibility, as well as superior strength.

[0152] Examples of embodiments of the present invention include the following: <1> Insulating inorganic particles, A dispersant having a carboxyl group or an acid anhydride group, A liquid composition for forming an insulating layer, comprising a binder, 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> This is a liquid composition for forming an insulating layer as described above. <3> The dispersant comprises at least one selected from the structural units represented by the following general formula (1), the structural units represented by the following general formula (2), and the structural units represented by the following general formula (3). <1> or the above <2> This is a liquid composition for forming an insulating layer as described above. [ka] [ka] [ka] (In general formulas (1) to (3), * represents a bonding site with an adjacent main chain structural unit, and M represents an ammonium salt.) <4> When viscosity A is measured using an e-type viscometer at 100 rpm, and viscosity B is measured using an e-type viscometer at 10 rpm, 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> This is a liquid composition for forming an insulating layer as described in any of the above. <5> The insulating inorganic particles are α-alumina or boehmite. <1> From the above <4> This is a liquid composition for forming an insulating layer as described in any of the above. <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> This is a liquid composition for forming an insulating layer as described in any of the above. <7> The aforementioned <1> From the above <6> This is a container characterized by containing a liquid composition for forming an insulating layer as described in any of the above. <8> The aforementioned <1> From the above <6> A container containing a liquid composition for forming an insulating layer as described in any of the following, The electrode manufacturing apparatus is characterized by having means for applying the aforementioned insulating layer forming liquid composition onto a substrate. <9> The means for applying the liquid composition for forming the insulating layer is an inkjet, <8> This is the electrode manufacturing apparatus described above. <10> Substrate and, An electrode composite layer provided on a part of the substrate, An electrode having an insulating layer that covers the boundary between the exposed portion of the substrate and the electrode composite layer, The insulating layer comprises insulating inorganic particles, a dispersant, and a binder. The dispersant comprises at least one selected from the structural units represented by the following general formula (1), the structural units represented by the following general formula (2), and the structural units 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 general formulas (1) to (3), * represents a bonding site with 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> These are the electrodes described in [reference]. <12> The insulating layer is provided at the boundary and at the end of the electrode composite layer, <10> or the above <11> These are the electrodes described in [reference]. <13> The insulating layer is provided on the boundary portion and on the upper surface of the electrode composite layer. <10> or the above <11> These are the electrodes described. <14> The peel strength of the insulating layer relative to the substrate is 50 N / m or more. <10> From the above <13> The electrode is one of the electrodes described in any of the following. <15> The aforementioned <10> From the above <14> This is an energy storage device characterized by comprising electrodes as described in any of the above.

[0153] <1> from <6> A liquid composition for forming an insulating layer as described in any of the following: <7> The container described above, <8> or <9> The electrode manufacturing apparatus described above, <10> from <14> An electrode as described in any of the following, and <15> The energy storage device described above can solve the problems of the conventional methods and achieve the objectives of the present invention. [Explanation of symbols]

[0154] 100 electrodes 1 Base 11 Exposed base part 2 Electrode composite layer 3. Insulating 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 Publication No. 2023-131728

Claims

1. A substrate and, An electrode composite layer provided on the substrate, A method for manufacturing an electrode having an insulating layer, The process includes a step of applying a liquid composition to the substrate using an inkjet to apply the liquid composition for generating the insulating layer, The liquid composition is Inorganic particles and A dispersant having a carboxyl group or an acid anhydride group, It contains a binder, A method for manufacturing an electrode, characterized in that the weight-average molecular weight of the binder is 25,000 or more and 80,000 or less.

2. The method for manufacturing an electrode according to claim 1, wherein the dispersant comprises at least one selected from the structural units represented by the following general formula (1), the structural units represented by the following general formula (2), and the structural units represented by the following general formula (3). 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 (In general formulas (1) to (3), * represents a bonding site with an adjacent main chain structural unit, and M represents an ammonium salt.)

3. A method for manufacturing an electrode according to claim 1, wherein when viscosity A is measured using an e-type viscometer at a rate of 100 rpm, and viscosity B is measured using an e-type viscometer at a rate of 10 rpm, the ratio of viscosity B to viscosity A [B / A] is 0.95 or more and 1.05 or less.

4. The method for manufacturing an electrode according to claim 1, wherein the content of the binder is 1% by mass or more and 7% by mass or less with respect to the total amount of inorganic particles in the insulating layer.

5. The method for manufacturing an electrode according to claim 1, wherein the inorganic particles are α-alumina or boehmite.

6. The method for manufacturing an electrode according to claim 1, wherein the median diameter of the inorganic particles is 200 nm or more and less than 1,000 nm.

7. The aforementioned liquid composition is a liquid composition for forming an insulating layer, The aforementioned liquid composition for forming the insulating layer is contained in a container, The method for manufacturing an electrode according to claim 1, characterized in that the insulating layer forming liquid composition is applied onto the substrate by means of applying the insulating layer forming liquid composition.

8. The liquid composition applied to the substrate is heated by a liquid composition heating means, The method for manufacturing an electrode according to claim 1, wherein the liquid composition heating means comprises one of a resistance heater, an infrared heater, or a fan heater.

9. A method for manufacturing an electrode according to Claim 1, The electrodes are The aforementioned substrate and, The electrode composite layer and, The substrate has an insulating layer that covers the boundary between the exposed portion and the electrode composite layer, The insulating layer comprises the inorganic particles, the dispersant having carboxyl groups or acid anhydride groups, and the binder. The method for manufacturing an electrode according to claim 1, characterized in that the dispersant comprises at least one selected from the structural units represented by the following general formula (1), the structural units represented by the following general formula (2), and the structural units represented by the following general formula (3). 【Chemistry 4】 【Transformation 5】 【Transformation 6】 (In general formulas (1) to (3), * represents a bonding site with an adjacent main chain structural unit, and M represents an ammonium salt.)

10. The method for manufacturing an electrode according to claim 9, wherein the insulating layer is provided at the boundary and at the end of the electrode composite layer.

11. The method for manufacturing an electrode according to claim 9, wherein the insulating layer is provided on the boundary portion and on the upper surface of the electrode composite layer.

12. The method for manufacturing an electrode according to claim 9, wherein the peel strength of the insulating layer on the substrate is 50 N / m or more.

13. A method for manufacturing an electrochemical element, comprising the step of manufacturing an electrode by the electrode manufacturing method described in any one of claims 1 to 8, characterized in that the electrode is used as a component.

14. A step of applying a liquid composition for forming an electrode composite layer to a part of the substrate, A step of heating the electrode composite layer-forming liquid composition applied to the substrate, A method for manufacturing an electrode according to claim 1, comprising a step of forming an electrode composite layer including the electrode composite material.

15. The method for producing an electrode according to claim 1, characterized in that the content of the inorganic particles is 20% by mass or more and 50% by mass or less with respect to the total amount of the liquid composition.

16. The method for manufacturing an electrode according to claim 1, characterized in that the surface tension of the liquid composition is 15 mN / m or more and 40 mN / m or less.

17. The method for manufacturing an electrode according to claim 1, characterized in that the inkjet that applies the liquid composition is applied while detecting the boundary between the exposed portion of the substrate and the electrode composite layer.

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