EP4681262A1

EP4681262A1 - Electrode, non-aqueous power storage element, and method of manufacturing electrode

Info

Publication number: EP4681262A1
Application number: EP24712963.8A
Authority: EP
Inventors: Hiroki Hagiwara; Keigo TAKAUJI; Daisuke NOSE; Takuya Saiga; Miku OHKIMOTO
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2023-03-17
Filing date: 2024-03-13
Publication date: 2026-01-21
Also published as: WO2024194743A1; CN121002666A

Abstract

An electrode is provided that includes a base, an electrode composite layer on the base, and an insulator layer on the electrode composite layer. The insulator layer includes a porous layer on the electrode composite layer and having a backbone and voids, and a particle layer on the porous layer and containing particles. A melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer. A volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

Description

[DESCRIPTION]

[Title of Invention]

ELECTRODE, NON-AQUEOUS POWER STORAGE ELEMENT, AND METHOD OF MANUFACTURING ELECTRODE

[Technical Field]

[0001]

The present disclosure relates to an electrode, a non-aqueous power storage element, and a method of manufacturing an electrode.

[Background Art]

[0002]

Electrochemical elements, such as secondary batteries including lithium ion secondary batteries, are installed in portable devices, hybrid vehicles, electric vehicles, and the like, and thus, the demand for electrochemical elements is increasing. Further, batteries are expected to be thinner to be used in various types of wearable devices and medical patches, and thus, the requirements (high output, high capacity, long battery life, and the like) for secondary batteries are diversifying.

For example, as an electrode in a secondary battery, there has been proposed an electrode for lithium secondary batteries that has high capacity, a good charging/discharging cycle, and excellent safety, in which an ion-permeable porous insulating layer derived from a heat- resistant cross-linked resin such as an imide polymer is formed on an outer surface of an electrode composite layer in the electrode (see, for example, PTL 1).

[Citation List]

[Patent Literature]

[0003]

[PTL 1]

WO 2014/106954

[Summary of Invention]

[Technical Problem]

[0004]

An object of the present invention is to provide an electrode that has excellent blocking resistance in any usage conditions and includes an insulator surface having excellent smoothness.

[Solution to Problem]

[0005]

An electrode according to embodiments of the present invention as a means for solving the above-described problems is described below. That is, an electrode includes a base, an electrode composite layer on the base, and an insulator layer on the electrode composite layer. The insulator layer includes a porous layer on the electrode composite layer and having a backbone and voids, and a particle layer on the porous layer and containing particles. A melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer, and a volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

[Advantageous Effects of Invention]

[0006]

According to embodiments of the present invention, an electrode is provided that has excellent blocking resistance in any usage conditions and includes an insulator surface having excellent smoothness.

[Brief Description of Drawings]

[0007]

A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.

[FIG. 1]

FIG. 1 is a schematic cross-sectional view of an electrode (negative electrode) according to an embodiment of the present invention.

[FIG. 2]

FIG. 2 is a schematic cross-sectional view of an electrode (positive electrode) according to an embodiment of the present invention.

[FIG. 3]

FIG. 3 is a schematic diagram illustrating an electrode manufacturing apparatus according to an embodiment of the present invention.

[FIG. 4]

FIG. 4 is a schematic diagram illustrating an electrode manufacturing apparatus according to an embodiment of the present invention.

[FIG. 5]

FIG. 5 is a schematic diagram illustrating an electrode manufacturing apparatus according to an embodiment of the present invention.

[FIG. 6]

FIG. 6 is a schematic diagram illustrating a method of manufacturing an electrode according to an embodiment of the present invention.

[FIG. 7]

FIG. 7 is a schematic diagram illustrating a modification of a liquid discharge device.

[FIG. 8]

FIG. 8 is a configuration diagram illustrating a printer using a drum-shaped intermediate transfer body as an electrode manufacturing apparatus according to an embodiment of the present invention.

[FIG. 9] FIG. 9 is a configuration diagram illustrating a printer using an intermediate transfer body shaped as an endless belt as the electrode manufacturing apparatus according to an embodiment of the present invention.

[FIG. 10]

FIG. 10 is a schematic diagram illustrating a moving body including an all-solid-state battery as a non-aqueous power storage element according to an embodiment of the present invention.

The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments] [0008]

In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.

Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In general, electrodes in secondary batteries such as lithium ion batteries are obtained by laminating an electrode composite layer containing an active material on a base. The surface of the electrode has fine irregularities from the active material. If defect portions such as scratches and irregularities exist on the surface of the electrode, specific substances accumulate in the defect portions, so that internal short circuits and leaks are more likely to occur due to physical contact with an electrode interface, and the performance including cycle characteristics and the like may deteriorate. Therefore, for the performance of a device, it is desired that the surface of the electrode is smooth.

As a means for solving such problems, a technique such as described in the electrode for lithium ion secondary batteries described in PTL 1 mentioned above is proposed, by which an ion-permeable porous insulating layer is formed on an electrode composite layer to prevent short circuits and leaks and improve the performance of a battery such as the cycle characteristics. However, the surface of the electrode for lithium ion secondary batteries described in PTL 1 above still has fine irregularities derived from the ion-permeable porous insulating layer, and there is still room for improvement in the smoothness of the surface of the electrode.

[0009]

As described in the electrode for lithium ion secondary batteries described in PTL 1 mentioned above, an outermost layer of the electrode is a porous layer derived from a resin, and thus, there is a problem that blocking occurs while manufacturing the electrode. Specifically, when an electrode (electrode sheet) having a porous layer derived from a resin as an outermost surface is wound up into a roll, adhesion (blocking) occurs between the porous layer and another layer, which causes problems such as damage of the electrode (and especially a separator). Further, if the outermost layer of the electrode is a porous layer derived from a resin, the porous layer may melt under high temperature conditions and/or high pressure conditions, resulting in problems such as blocking and deterioration of the separator.

Therefore, it is desired that the outermost layer of the electrode has excellent blocking resistance.

[0010]

As a result of extensive studies, the inventors of the present invention have found that the above-described problems, that is, smoothness and blocking resistance, can be solved by forming, on the porous layer, a particle layer containing particles having a high melting point or a high glass transition point. Specifically, a configuration is described below.

As mentioned above, the surface of the porous layer has fine irregularities derived from the porous structure. Therefore, by covering the surface of the porous layer with a particle layer, the smoothness of the surface of the electrode (and especially the insulator) can be improved. This is because the surface roughness (degree of irregularity) of the particle layer is smaller than the surface roughness of the porous layer.

Moreover, by covering the surface of the porous layer with a particle layer, physical contact between the porous layer and another member can be prevented, and as a result, it is possible to improve the blocking resistance.

The particles contained in the particle layer have a higher melting point (Tma) or a higher glass transition temperature (Tga) than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer. Therefore, the particles contained in the particle layer can prevent the porous layer from melting and denaturing under high temperature conditions and/or high pressure conditions. As a result, it is possible to improve the blocking resistance and suppress deterioration of the separator (the insulator).

[0011]

The electrode of the present embodiment will be described below with reference to the drawings. In the drawings, the same constituent components are denoted by the same reference numerals, and overlapping parts of the description may be omitted.

[0012]

FIG. 1 is a schematic cross-sectional view of an electrode (negative electrode) of the present embodiment.

A negative electrode 1000 includes a negative electrode base 1001, a negative electrode composite layer 1002 formed on the negative electrode base 1001, a porous layer 1003 formed on the negative electrode composite layer 1002, and a particle layer 1004 formed on the porous layer 1003. In the present specification, the porous layer 1003 and the particle layer 1004 may be collectively referred to as an “insulator layer.” [0013]

FIG. 2 is a schematic cross-sectional view of an electrode (positive electrode) of the present embodiment.

A positive electrode 2000 includes a positive electrode base 2001, a positive electrode composite layer 2002 formed on the positive electrode base 2001, a porous layer 2003 formed on the positive electrode composite layer 2002, and a particle layer 2004 formed on the porous layer 2003. In the present specification, the porous layer 2003 and the particle layer 2004 may be collectively referred to as an “insulator layer.” [0014]

The present embodiment will be described in detail below.

[0015]

(Electrode)

An electrode of the present embodiment includes a base, an electrode composite layer, and an insulator layer, and may include other layers, if desired.

[0016]

<Base>

The material of the base is not particularly limited and can be appropriately selected according to a purpose, as long as the material has a conductivity by which the material functions as a current collector. Examples of the material include, but are not limited to, metals such as nickel, aluminum, copper, and titanium.

The shape of the base is not particularly limited and can be appropriately selected according to a purpose. However, a plate-like or foil-like shape is preferable in order to form an electrode composite layer, which will be described later, on both surfaces of the base and improve the battery capacity by laminating a plurality of electrodes.

Examples of the base include, but are not limited to, an etched foil in which fine holes are formed by etching the above-mentioned metal, and a perforated electrode base used in a lithium ion capacitor. Further, the base may be obtained by vapor-depositing, on a flat base such as glass or plastic, a thin film derived from a conductor or a semiconductor, or a conductive electric film.

[0017]

The electrode composite layer is a layer containing an active material, which is provided on the base, and if desired, may contain a binder (binding agent) such as a resin, a conductive auxiliary agent, a dispersant for forming an electrode composite layer, and other components. In the present specification, the electrode composite layer used for the positive electrode may be referred to as a “positive electrode composite layer,” and the electrode composite layer used for the negative electrode may be referred to as a “negative electrode composite layer.” In the present specification, the active material contained in the electrode composite layer of the positive electrode may be referred to as a “positive electrode active material,” and the active material contained in the electrode composite layer of the negative electrode may be referred to as a “negative electrode active material.” [0018]

The shape of the electrode composite layer is not particularly limited and can be appropriately selected according to a purpose. However, the shape is preferably a shape similar to the shape of the base, that is, a plate-like shape.

[0019]

<<Positive Electrode Active Material > >

The positive electrode active material is not particularly limited and can be appropriately selected according to a purpose, as long as the positive electrode active material is a material that can reversibly intercalate and release alkali metal ions. Examples of the positive electrode active material include, but are not limited to, a transition metal compound containing an alkali metal. Examples of the transition metal compound containing an alkali metal include, but are not limited to, a transition metal compound containing lithium, a chalcogen compound, and manganese dioxide.

[0020]

Examples of the transition metal compound containing lithium include, but are not limited to, complex oxides containing lithium and at least one element selected from the group including cobalt, manganese, nickel, chromium, iron, and vanadium. More specifically, examples of the transition metal compound containing lithium include, but are not limited to, transition metal oxides containing lithium such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide, and olivine-type lithium salts such as LiFePCE.

The transition metal oxides containing lithium are metal oxides containing lithium and a transition metal or metal oxides in which a part of the transition metal in the metal oxide is replaced with a different element. Examples of the different element include, but are not limited to, Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B. Among these elements, Mn, Al, Co, Ni, and Mg are preferred. These different elements may be contained alone or in combination of two or more elements.

[0021]

The chalcogen compound is not particularly limited and can be appropriately selected according to a purpose. Examples of the chalcogen compound include, but are not limited to, titanium disulfide and molybdenum disulfide.

[0022]

These positive electrode active materials may be used alone or in combination of two or more types.

[0023]

The positive electrode active material may be appropriately synthesized, or a commercially available product may be used as the positive electrode active material. Commercially available products of the positive electrode active material include, but are not limited to, lithium nickelate of the trade name Lithium Nickelate 503H (manufactured by JFE Mineral Co., Ltd.).

[0024]

<< Negative Electrode Active Material > >

The negative electrode active material is not particularly limited and can be appropriately selected according to a purpose, as long as the negative electrode active material is a material that can reversibly intercalate and release alkali metal ions. Examples of the negative electrode active material include, but are not limited to, carbon materials including graphite having a graphite-type crystal structure. More specifically, examples of the negative electrode active material include, but are not limited to, natural graphite, spherical or fibrous artificial graphite, non-graphitizable carbon (hard carbon), and easily graphitizable carbon (soft carbon).

In addition to the carbon material, lithium titanate can also be used as the negative electrode active material. Further, from the viewpoint of increasing the energy density of the lithium ion secondary battery when providing a negative electrode in a lithium ion secondary battery, materials having high capacity such as silicon, tin, silicon alloys, tin alloys, silicon oxide, silicon nitride, and tin oxide can also be suitably used as the negative electrode active material.

[0025]

The negative electrode active material may be appropriately synthesized, or a commercially available product may be used as the negative electrode active material. Examples of commercially available products as the negative electrode active material include, but are not limited to, a product of the trade name SCMG-XRs (artificial graphite for lithium ion batteries, manufactured by Showa Denko K.K.).

[0026]

<<Binder>>

The electrode composite layer may contain a binder (binding agent) in addition to the active material.

The binder is not particularly limited and can be appropriately selected according to a purpose. Examples of the binder include, but are not limited to, polyvinylidene fluoride (polyvinylidene difluoride: PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polyacrylic acid methyl ester, polyacrylic acid ethyl ester, polyacrylic acid hexyl ester, polymethacrylic acid, polymethacrylic acid methyl ester, polymethacrylic acid ethyl ester, polymethacrylic acid hexyl ester, polyvinyl acetate, polyvinyl pyrrolidone, polyether, polyether sulfone, hexafluoropolypropylene, styrene butadiene rubber, and carboxymethyl cellulose.

The binder may also be a copolymer obtained from a material such as a polymer or a monomer selected from two or more types of monomers including tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene.

These binders may be used alone or in combination of two or more types.

[0027]

<<Conductive Auxiliary Agent>>

The electrode composite layer may contain a conductive auxiliary agent in addition to the active material.

The conductive auxiliary agent is not particularly limited and can be appropriately selected according to a purpose. Examples of the conductive auxiliary agent include, but are not limited to, graphite materials such as natural graphite and artificial graphite, types of carbon black such as acetylene black, Ketjenblack, channel black, furnace black, lamp black, and thermal black, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and organic conductive materials such as phenylene derivatives and graphene derivatives.

The conductive auxiliary agent may form a composite compound with the active material. [0028] <<Dispersant for Forming Electrode Composite Layer>>

The dispersant for forming an electrode composite layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include, but are not limited to, polymer dispersants, surfactants, and inorganic dispersants.

Examples of the polymer dispersants include, but are not limited to, polycarboxylic acid dispersants, naphthalene sulfonic acid formalin condensate dispersants, polyethylene glycol, polycarboxylic acid partial alkyl ester dispersants, polyether dispersants, and polyalkylene poly amine dispersants.

Examples of the surfactants include, but are not limited to, alkyl sulfonic acid dispersants, quaternary ammonium salt dispersants, higher alcohol alkylene oxide dispersants, polyhydric alcohol ester dispersants, and alkyl polyamine dispersants.

Examples of the inorganic dispersants include, but are not limited to, polyphosphate dispersants.

[0029]

<< Other Components >>

The other components contained in the electrode composite layer are not particularly limited and can be appropriately selected according to a purpose. Examples of the other components include, but are not limited to, pH adjusters, rust inhibitors, preservatives, fungicides, antioxidants, anti-reduction agents, evaporation accelerators, and chelating agents.

[0030]

[Average Thickness of Positive Electrode Composite Layer] The average thickness of the positive electrode composite layer is not particularly limited and can be set appropriately according to a purpose. However, the average thickness is preferably 10 pm or more and 300 pm or less, and more preferably 40 pm or more and 150 pm or less. The average thickness of the positive electrode composite layer is preferably 10 pm or more, to improve the energy density in an electrochemical element such as a lithium ion secondary battery.

The average thickness of the positive electrode composite layer is preferably 300 pm or less, to improve the load characteristics of an electrochemical element such as a lithium ion secondary battery.

[0031]

[Average Thickness of Negative Electrode Composite Layer]

The average thickness of the negative electrode composite layer is not particularly limited and can be set appropriately according to a purpose. However, the average thickness is preferably 10 pm or more and 450 pm or less, and more preferably 20 pm or more and 100 pm or less. The average thickness of the negative electrode composite layer is preferably 10 pm or more, to improve the energy density in an electrochemical element such as a lithium ion secondary battery.

The average thickness of the negative electrode composite layer is preferably 450 pm or less, to improve the cycle characteristics of an electrochemical element such as a lithium ion secondary battery.

[0032]

A method of measuring the average thickness of the electrode composite layer is not particularly limited. For example, the average thickness may be measured by the following method.

[Method of Measuring Average Thickness of Electrode Composite Layer]

The electrode is cut to obtain a square piece of 5 mm that includes the electrode base, the electrode composite layer, and the insulator layer. The square piece is immersed into a degassed resin (two-component mixture, 30-minute curing epoxy resin, manufactured by Devcon), and cured at 40°C in an oven for 12 hours. After the square piece of the electrode is sufficiently cured, the square piece is cut in the thickness direction by using a razor, ion milling, a micro-microtome, or the like, to prepare a cross-sectional sample. The cross section of the obtained cross-sectional sample is finished by using a cross section polisher (SM-09010, manufactured by JEOL, Ltd.) under conditions including an acceleration voltage of 5.0 kV and a beam current of 120 pA. Next, a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) is used to randomly capture a plurality of images of the cross section including an upper end and a lower end of the electrode composite layer under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times.

The plurality of obtained images are imported into TIFF images, and image analysis software (IMAGE-PRO PLUS, manufactured by Media Cybernetics) is used to calculate the area of the electrode composite layer in the cross section and the length of the electrode composite layer in the width direction in the cross section, that is, the length in the horizontal direction with respect to the electrode base, from the scale bar and the number of pixels obtained by the image analysis. The film thickness is calculated by dividing the area by the length in the width direction.

Note that the “average thickness” is determined by calculating an average of measurement values obtained at 10 points, among the plurality of obtained images.

[0033]

The electrode composite layer can be prepared by using the liquid composition for forming an electrode composite layer. Note that a specific method of preparing the electrode composite layer will be described later.

[0034]

<<Liquid Composition for Forming Electrode Composite Layer>>

The liquid composition for forming an electrode composite layer may contain an active material, a dispersion medium, a binder, a conductive auxiliary agent, a dispersant for forming an electrode composite layer, and other components.

The active material, the binder, the conductive auxiliary agent, the dispersant for forming an electrode composite layer, and the other components are the same as those described in the section <Electrode Composite Layer> above, and thus, description thereof will be omitted. [0035]

- Dispersion Medium -

Examples of the dispersion medium include, but are not limited to, aqueous dispersion media such as water, ethylene glycol, propylene glycol, and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 2-pyrrolidone, cyclohexanone, butyl acetate, mesitylene, 2-n- butoxymethanol, 2-dimethylethanol, and N,N-dimethylacetamide. These dispersion media may be used alone or in combination of two or more types.

[0036]

The viscosity at 25°C of the liquid composition for forming an electrode composite layer is preferably 200 mPa- smPa- s or less, more preferably 100 mPa- s or less, and even more preferably 50 mPa- s or less.

The viscosity at 25°C of the liquid composition for forming an electrode composite layer is preferably 200 mPa- s or less, because in this case, a discharge failure is less likely to occur when the liquid composition for forming an electrode composite layer is discharged by a liquid discharge device.

A method of measuring the viscosity of the liquid composition for forming an electrode composite layer is not particularly limited and can be appropriately selected according to a purpose. For example, the viscosity can be measured in conformity with Japanese Industrial Standards (JIS) Z88O3. A device used for measuring the viscosity is not particularly limited and can be appropriately selected according to a purpose. Examples of the device include, but are not limited to, a TV25 type viscometer (cone plate viscometer, manufactured by TOKI SANGYO). [0037]

< Insulator Lay er >

The insulator layer is a layer provided on the electrode composite layer, and includes a porous layer and a particle layer.

[0038]

<<Porous Layer>>

The porous layer is a layer provided on the electrode composite layer and has a backbone and voids. If desired, the porous layer may include a dispersant for forming a porous layer, a viscosity modifier, an additive, and other components.

[0039]

The structure of the porous layer is not particularly limited and can be appropriately selected according to a purpose, as long as the structure includes a backbone and voids. However, the structure preferably includes a backbone having a network structure branched in a three- dimensional direction and voids that communicate, to ensure electrolyte permeability and ionic conductivity in secondary batteries. In other words, the structure of the porous layer is preferably a co-continuous structure (monolith structure), that is, a two-phase continuous structure in which both the backbone and the voids are continuous.

Note that the term “voids” in the present specification also includes voids that contain porogen inside, which occur when the porous layer is formed by a wet-on- wet method. The porous layer preferably has a two-phase continuous structure, because in this case, the electrolyte permeability and ion permeability are further improved, and the cycle characteristics of the secondary battery are improved.

[0040]

The backbone in the porous layer preferably contains a cured product of a polymerizable compound (monomer), and more preferably contains only a cured product of a polymerizable compound. The polymerizable compound is preferably a photocurable resin.

[0041]

The cured product preferably has a cross-linked structure, to improve the physical strength of the porous layer.

[0042]

The cross-sectional shape of the voids in the porous layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include a substantially circular shape, a substantially elliptical shape, and a substantially polygonal shape. These shapes may be used alone or a plurality of these shapes may be combined.

[0043]

[Average Diameter of Voids]

In the electrode of the present embodiment, the average diameter of the voids in the porous layer is smaller than the volume average particle diameter of particles in the particle layer described below. Here, the term “average diameter” refers to the average length of the longest line segment of one void portion in a cross section obtained by cutting the porous layer at a right angle to the surface direction.

The average diameter of the voids in the porous layer is not particularly limited and can be appropriately selected according to a purpose, as long as the average diameter is smaller than the volume average particle diameter of the particles in the particle layer described below. However, the average diameter of the voids is preferably 10 nm or more and 200 nm or less. The average diameter of the voids is preferably 10 nm or more, because in this case, the smoothness is improved and electrolyte permeability into the porous layer and the electrode composite layer is improved. The average diameter of the voids is preferably 200 nm or less, to improve the compression resistance of the porous layer. If the average diameter of the voids is large, the particles in the particle layer partially enter the voids, and the film thickness decreases in a portion where the particles enter, so that the problem of a deterioration in smoothness can be solved. Further, in the portion where the film thickness decreases, the porous layer may be slightly exposed, which solves the problem of blocking.

[0044]

A method of measuring the average diameter of the voids in the porous layer is not particularly limited. For example, the average diameter of the voids may be measured by the following method.

[Method of Measuring Average Diameter of Voids]

The porous layer is cut out as a porous structure body having a size of 5 mm x 10 mm, and osmium staining is performed by using osmium tetroxide (VIII) (manufactured by EM Co., Ltd.). The cut-out porous structure body is placed in a bottle containing a small amount of the aqueous solution mentioned above, without the porous structure body contacting the aqueous solution, and the porous structure body is allowed to stand in the sealed bottle for 30 minutes to stain the porous structure body. Subsequently, the porous structure body is dried in a fume hood for 1 hour to obtain a stained sample.

After being sufficiently dried, the sample is subjected to vacuum impregnation using a two- component mixed type epoxy resin (manufactured by ITW Performance Polymers & Fluids Japan). Afterwards, a cross section of the sample is cut out by using a cryo-FIB/SEM (manufactured by FEI Company Japan Ltd.) and the cross section is observed. This operation including cutting and observation is repeated at a pitch of 10 nm in the depth direction to obtain a plurality of observed image groups. The obtained image groups are binarized and images are combined by using GeoDict (manufactured by Math 2 Market GmbH) to create a 3D structure of a 3 pm square, and the average diameter of an epoxy resin region (void region) within the structure is calculated. At this time, the binarization conditions can be appropriately set so that a boundary between a porous backbone region stained with osmium and the epoxy resin region not stained with osmium is clearly observable.

[0045]

[Porosity] The porosity in the porous layer is not particularly limited and can be appropriately selected according to a purpose. However, the porosity is preferably 30% or more and 60% or less, and more preferably 35% or more and 60% or less. The porosity is preferably 30% or more, to improve the ion permeability of the porous layer. The porosity is preferably 60% or less, to improve the compression resistance of the porous layer.

[0046]

[Distribution of Voids]

The distribution of the voids in the porous layer is not particularly limited and can be appropriately selected according to a purpose. However, it is preferable that the voids are distributed uniformly in the thickness direction, to obtain excellent electrolyte permeability. Specifically, the difference between the porosity in a region (A) and the porosity in a region (B) (may be referred to as porosity difference hereinafter) is preferably within 20%, and more preferably within 10%.

Note that the region (A) indicates a region separated by 1 pm toward the particle layer from an uppermost end portion of the porous layer in a cross section obtained by cutting the porous layer at a right angle to the surface direction.

In the cross section obtained by cutting the porous layer at a right angle to the surface direction, the region (B) refers to a region separated by 1 pm toward the electrode composite layer from a contact line between the porous layer and the particle layer.

[0047]

A method of measuring the porosity of the porous layer is not particularly limited. For example, the porosity may be measured by the following method.

[Method of Measuring Porosity]

The electrode is cut into square pieces of 5 mm, an unsaturated fatty acid (commercially available butter) is filled into a container, and the electrode is subjected to osmium staining. A cross-sectional structure of an inner portion of the electrode is cut out by using an FIB, and the porosity in the resin is measured by using SEM. Further, the porosity difference is determined by trimming the region (A) and the region (B) in the obtained binarized image and calculating an area ratio of void portions in each of the region (A) and the region (B).

[0048]

[Coverage Rate]

The coverage rate of the porous layer with respect to the electrode composite layer is not particularly limited and can be appropriately selected according to a purpose. However, the coverage rate is preferably 90% or more, more preferably 95% or more, even more preferably 98% or more, and particularly preferably 99% or more. The coverage rate is preferably 90% or more, to improve the compression resistance of the porous layer.

[0049]

As illustrated in FIGs. 1 and 2, a part of the porous layer may be integrally formed with a part of the positive electrode composite layer or the negative electrode composite layer. Here, the term “integrally formed” does not mean that the members are simply laminated, but refers to a state where a part of an upper layer enters a lower layer and an interface is not clear, and a state where a part of the substance forming the upper layer and a part of the substance forming the lower layer are bound together.

[0050]

[Average Thickness of Porous Layer]

In the present specification, the term “average thickness of the porous layer” refers to a thickness from an upper surface of the porous layer 1003 or the porous layer 2003 in FIGs. 1 and 2 to a lowermost portion of the porous layer present inside the negative electrode composite layer 1002 or the positive electrode composite layer 2002.

The average thickness of the porous layer is not particularly limited and can be appropriately selected according to a purpose. However, the average thickness is preferably 5 pm or more, to improve the smoothness, the blocking resistance, and the insulation properties of the porous layer.

The average thickness of the porous layer is not particularly limited and can be selected appropriately according to a purpose. However, ions can move more easily when the interval between the positive electrode and the negative electrode in a secondary battery is narrower, and thus, the average thickness of the porous layer is preferably 20 pm or less, to improve the cycle characteristics of secondary batteries.

[0051]

A method of measuring the average thickness of the porous layer is not particularly limited. For example, the average thickness may be measured by the following method. [Method of Measuring Average Thickness of Porous Layer]

The electrode is cut to obtain a square piece of 5 mm that includes the electrode base, the electrode composite layer, and the insulator layer. The square piece is immersed into a degassed resin (two-component mixture, 30-minute curing epoxy resin, manufactured by Devcon), and cured at 40°C in an oven for 12 hours. After the square piece of the electrode is sufficiently cured, the square piece is cut in the thickness direction by using a razor, ion milling, a micro-microtome, or the like, to prepare a cross-sectional sample. The cross section of the obtained cross-sectional sample is finished by using a cross section polisher (SM-09010, manufactured by JEOL, Ltd.) under conditions including an acceleration voltage of 5.0 kV and a beam current of 120 pA. Next, a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) is used to randomly capture a plurality of images of the cross section including an upper end and a lower end of the porous layer under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times. The plurality of obtained images are imported into TIFF images, and image analysis software (IMAGE- PRO PLUS, manufactured by Media Cybernetics) is used to calculate the area of the porous layer in the cross section and the length of the porous layer in the width direction in the cross section, that is, the length in the horizontal direction with respect to the electrode base, from the scale bar and the number of pixels obtained by the image analysis. The film thickness is calculated by dividing the area by the length in the width direction. Note that the “average thickness” is determined by calculating an average of measurement values obtained at 10 points, among the plurality of obtained images.

[0052]

When a part of the porous layer and a part of the electrode composite layer are integrally formed, a thickness part of 0.5% or more of the average thickness of the porous layer is preferably present inside the electrode composite layer. Moreover, it is preferable that a thickness part of 1.0% or more of the average thickness of the porous layer is present inside the electrode composite layer.

If a thickness part of 0.5% or more of the average thickness of the porous layer is present inside the electrode composite layer, an anchor effect occurs between the electrode composite layer and the porous layer. Thus, it is possible to suppress peeling and displacement of the porous layer due to compression.

[0053]

The porous layer can be prepared by using a liquid composition for forming a porous layer (maybe also referred to as “porous layer forming liquid composition”). Note that a specific method of preparing the porous layer will be described later.

[0054]

<<Liquid Composition for Forming Porous Layer>>

The liquid composition for forming a porous layer contains a polymerizable compound, and if desired, may contain a solvent for forming a porous layer, a dispersant for forming a porous layer, a polymerization initiator, an antifoaming agent, and other components.

The liquid composition for forming a porous layer preferably contains a polymerizable compound as a main component.

Here, the expression “contains a polymerizable compound as a main component” indicates that the content of the polymerizable compound is 50 mass% or more with respect to the total amount of the liquid composition for forming a porous layer.

[0055]

- Polymerizable Compound -

The polymerizable compound corresponds to a resin precursor for forming the backbone in the porous layer, and is a compound that can form a crosslinkable structure body by stimulation with light, heat, or the like.

Specific examples of the polymerizable compound include, but are not limited to, acrylate resins, methacrylate resins, urethane acrylate resins, vinyl ester resins, unsaturated polyesters, epoxy resins, oxetane resins, vinyl ethers, and resins in which an ene-thiol reaction is utilized. Among these resins, acrylate resins, methacrylate resins, urethane acrylate resins, and vinyl ester resins are preferably used, because in this case, it is possible to easily form a structure body by utilizing radical polymerization.

[0056]

The polymerizable compound preferably has a radical-polymerizable functional group. The number of radical-polymerizable functional groups is not particularly limited. The polymerizable compound may be monofunctional, difunctional, trifunctional, or higher functional. Further, the polymerizable compound having the radical-polymerizable functional group may be a monomer or an oligomer.

Among these compounds, polymerizable compounds having two or more radical- polymerizable functional groups are preferred from the viewpoint of improving the compression resistance of the porous layer.

These compounds may be used alone or in combination of two or more compounds. [0057]

Examples of polymerizable compounds having one radical-polymerizable functional group include, but are not limited to, 2-(2-ethoxyethoxy)ethyl acrylate, methoxypolyethylene glycol monoacrylate, methoxypolyethylene glycol monomethacrylate, phenoxy polyethylene glycol acrylate, 2-acryloyloxyethyl succinate, 2-ethylhexyl acrylate, 2 -hydroxy ethyl acrylate, 2- hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexylcarbitol acrylate, 3- methoxybutyl acrylate, benzyl acrylate, cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxy tetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomers.

[0058]

Examples of polymerizable compounds having two radical -polymerizable functional groups include, but are not limited to, 1,3 -butanediol diacrylate, 1,4-butanediol diacrylate, 1,4- butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, EO- modified bisphenol A diacrylate, EO-modified bisphenol F diacrylate, neopentyl glycol diacrylate, and tricyclodecane dimethanol diacrylate. [0059]

Examples of polymerizable compounds having three or more radical-polymerizable functional groups include, but are not limited to, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane ethoxytriacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, caprolactone- modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerin propoxy triacrylate, ECH-modified glycerol triacrylate, EO-modified glycerol triacrylate, PO- modified glycerol triacrylate, tris(acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphate triacrylate, and 2,2,5,5-tetrahydroxymethyl cyclopentanone tetraacrylate.

[0060] The glass transition temperature (Tg) of the cured product obtained by curing the polymerizable compound is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher.

The glass transition temperature (Tg) of the cured product is preferably 100°C or higher, because in this case, the porous layer is not denatured at high temperatures and maintains the insulation properties.

[0061]

- Solvent for Forming Porous Layer -

The solvent for forming a porous layer (maybe also referred to as “porous layer forming solvent”) may be referred to as a porogen. A porogen is a liquid solvent that can dissolve components in the liquid composition for forming a porous layer, particularly the polymerizable compound, and that can separate the polymerizable compound by phase separation as the polymerization progresses.

Specific examples of the porogen include, but are not limited to, ethers, higher alcohols, lactones, esters, amides, and hydrocarbons.

Examples of the ethers include, but are not limited to, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and dipropylene glycol monomethyl ether.

Examples of the higher alcohols include, but are not limited to, 1 -octanol, 2-ethylhexanol, 1- nonanol, 1 -decanol, undecyl alcohol, and lauryl alcohol.

Examples of the lactones include, but are not limited to, y-butyrolactone.

Examples of the esters include, but are not limited to, propylene carbonate, methyl tetradecanoate, methyl decanoate, and methyl myristate.

Examples of the amides include, but are not limited to, N,N-dimethylacetamide.

Examples of the hydrocarbons include, but are not limited to, tridecane, tetradecane, and pentadecane.

These porogens may be used alone or in combination of two or more types. [0062]

- Polymerization Initiator -

The polymerization initiator is not particularly limited and can be appropriately selected according to a purpose. For example, a photo-radical generator can be used as the polymerization initiator.

Examples of the photo-radical generator include, but are not limited to, benzophenone, acetophenone derivatives, a-hydroxy- or a- aminoacetophenone, 4-aroyl- 1,3 -dioxolane, benzyl ketal, 2,2-diethoxyacetophenone, p-dimethylaminoacetophene, p- dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, pp'- dichlorobenzophene, pp'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzyl dimethyl ketal, tetramethylthiuram monosulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, azobisisobutyronitrile, benzoin peroxide, di-tert-butyl peroxide, 1- hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl- 1 -phenyl- 1 -one, l-(4- isopropylphenyl)-2-hydroxy-2-methylpropan-l-one, methylbenzoylformate, benzoin alkyl ethers and esters such as benzoin isopropyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin ether, benzoin isobutyl ether, benzoin n-butyl ether, and benzoin n-propyl, 1- hydroxy-cyclohexyl-phenyl-ketone, 2-benzyl-2-dimethylamino- 1 -(4-morpholinophenyl)- butanone- 1 , 1 -hydroxy-cy clohexyl-phenyl-ketone, 2,2-dimethoxy- 1 ,2-diphenylethan- 1 -one, bis(r|5-2,4-cyclopentadien-l-yl)-bis(2,6-difluoro-3-(lH-pyrrol-l-yl)-phenyl)titanium, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-l[4-(methylthio)phenyl]-2- morpholinopropan-l-one, 2-hydroxy-2-methyl-l-phenyl-propan-l-one (DAROCUR 1173), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, l-[4-(2 -hydroxy ethoxy)- phenyl]-2-hydroxy-2-methyl-l -propane- 1 -one monoacylphosphine oxide, bisacylphosphine oxide or titanocene, fluorescene, anthraquinone, thioxanthone or xanthone, lophine dimer, trihalomethyl compounds or dihalomethyl compounds, active ester compounds, and organoboron compounds.

In addition to the photo-radical generators mentioned above, photo-crosslinking type radical generators such as bisazide compounds, thermal polymerization initiators that generate radicals by heat, photo-acid generators that generate acids by light irradiation, and the like can be used.

These polymerization initiators may be used alone or in combination of two or more types. [0063]

- Other Components -

Examples of other components in the liquid composition for forming a porous layer include, but are not limited to, ethylene carbonate and vinylene carbonate. These components are preferably included to improve the cycle life of the electrode.

[0064]

<<Particle Layer>>

The particle layer is a layer that is provided on the porous layer and contains particles, and if desired, may contain a dispersant for forming a particle layer, a binder, a surfactant, and other components.

By providing the particle layer as an outermost layer of the electrode, it is possible to improve the smoothness of the surface of the electrode (and particularly the insulator). Moreover, if the surface of the porous layer is covered with the particle layer, physical contact between the porous layer and other members can be prevented, and as a result, the blocking resistance can be improved.

[0065]

In the present specification, the “smoothness” can be expressed by measuring the surface roughness of the electrode, that is, the surface roughness of the particle layer.

The surface roughness of the particle layer is not particularly limited and can be selected appropriately according to a purpose. However, the surface roughness is preferably 7 pm or less, more preferably 5 pm or less, and even more preferably 3 pm or less.

When the surface roughness of the particle layer is 7 pm or less, it is possible to suppress variations in the battery performance originating from variations in the thickness of the particle layer. Further, it is possible to suppress peeling from protruding portions of the surface irregularities in the particle layer, improve the durability of the film, and as a result, obtain an insulator layer having high strength.

[0066]

A method of measuring the surface roughness is not particularly limited and can be appropriately selected according to a purpose. For example, the surface roughness can be measured by using a laser microscope. Examples of the laser microscope include, but are not limited to, VK-X3000 (magnification: 50 times, manufactured by Keyence Corporation). [0067] [Coverage Rate of Particle Layer with Respect to Porous Layer]

The coverage rate of the particle layer provided on the porous layer is not particularly limited and can be appropriately selected according to a purpose. However, the coverage rate is preferably 40% or more, more preferably 60% or more, even more preferably 90% or more, and particularly preferably 99% or more.

When the coverage rate of the particle layer is 40% or more, the surface of the porous layer can be sufficiently covered by the particle layer, and the heat resistance, the surface abrasion resistance, and the durability can be improved without variation throughout the layer. As a result, it is possible to obtain an insulator layer having high strength.

In particular, in battery applications including a power storage element such as batteries and a power generation element such as fuel cells, when the insulator layer is used as an insulator layer formed on an electrode as a base, it is possible to obtain an insulator layer having high strength, and thus, the insulator layer can be made thinner. In general, when the insulator layer is made thinner, the mechanical strength of the insulator layer decreases compared to a thicker film. In this case, the insulator layer is easily deformed by an impact from the outside or pressure within the element, so that it is not possible to maintain the insulation properties. Thus, there is a problem that the original function as a separator cannot be guaranteed. However, according to the present embodiment, it is possible to obtain an insulator layer having sufficiently high mechanical strength. Therefore, even if the insulator layer is formed as a thin film, a function provided by the insulator layer can be sufficiently obtained.

If the insulator layer is formed as a thin film, the distance between electrodes decreases, which reduces the electrical resistance (internal resistance) within the battery, making it possible to obtain high battery performance such as input/output characteristics.

Further, if the insulator layer is formed as a thin film, it is expected that a battery having higher capacity and smaller size can be obtained.

[0068]

[Method of Measuring Coverage Rate of Particle Layer with Respect to Porous Layer] A method of measuring the coverage rate of the particle layer with respect to the porous layer is not particularly limited. For example, the coverage rate may be measured by the following method. The surface of the particle layer on the porous layer is observed by using a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times.

Thus, a reflected electron image of the particle layer formed on the porous layer is obtained. Subsequently, the obtained image is imported into a TIFF image and binarized by using image analysis software (IMAGE-PRO PLUS, manufactured by Media Cybernetics) to calculate the coverage rate of the particle layer on the porous layer. At this time, the binarization conditions can be appropriately set, so that the boundary between a porous layer region and a particle layer region is clearly observable. A method of identifying the porous layer region and the particle layer region is not particularly limited, as long as each region can be identified. Examples of the method include, but are not limited to, an identification method by the color, shape, size, and the like of the particle layer, or an identification method by elemental analysis mapping and the like.

[0069]

[Melting Point and Glass Transition Temperature]

In the present specification, the melting point of the particles may be referred to as “Tma,” the glass transition temperature of the particles may be referred to as “Tga,” the melting point of the porous layer may be referred to as “Tmb,” and the glass transition temperature of the porous layer may be referred to as “Tgb.”

In the electrode of the present embodiment, the melting point (Tma) and the glass transition temperature (Tga) of the particles are higher than the melting point (Tmb) and the glass transition temperature (Tgb) of the porous layer. In other words, the melting point (Tma) of the particles included in the particle layer is higher than the melting point (Tmb) of the porous layer, and the glass transition temperature (Tga) of the particles included in the particle layer is higher than the glass transition temperature (Tgb) of the porous layer. By such a relationship between the particles and the porous layer, it is possible to prevent the porous layer from melting under high temperature conditions and/or high pressure conditions. As a result, the blocking resistance can be improved and deterioration of the separator (insulator) can also be suppressed.

[0070]

A method of measuring the melting point (Tma) and the glass transition temperature (Tga) of the particles, and a method of measuring the melting point (Tmb) and the glass transition temperature (Tgb) of the porous layer are not particularly limited. For example, the following methods may be used.

[Method of Measuring Melting Point (Tma) of Particles]

The glass transition temperature of the particles and the porous layer is measured by using a DSC (Q-2000, manufactured by TA Instruments). In a specific measurement method, 5 mg of the solid content of the particles or the porous layer is filled into a sample container made of aluminum. The sample container is placed in the measurement device, cooled to 0°C under a nitrogen stream, held for 5 minutes, and then heated at a rate of 10°C/min to 400°C to delete the thermal history as a first cycle. Afterwards, the temperature is immediately decreased to 0°C, held for 5 minutes, and then raised to 400°C at a rate of 10°C/min as a second cycle. The DSC curve during the temperature increase in the second cycle is selected, to determine the glass transition temperature Tg by the midpoint method using a midpoint between the starting temperature and the ending temperature in the change of the intercept, and determine the melting point Tm at the apex of the endothermic peak.

If it is not possible to determine Tg or Tm by the above-described method, Tg is omitted, and a temperature of 400°C or higher or a literature value of a main component is used as Tm. For example, in the case of alumina, Tg is omitted, and 2000°C is used as Tm.

[0071]

In the electrode of the present embodiment, the volume average particle diameter (nm) of the particles is larger than the average diameter (nm) of the voids in the porous layer. It is preferable that such a relationship exists, because in this case, in the process of applying a liquid composition for forming a particle layer onto the porous layer, which will be described later, the particles enter the voids, and thus, it is possible to solve the problem in which it is not possible to form a particle layer having a smooth surface.

In addition, such a relationship is preferable, because in this case, it is possible to solve the problem that the liquid composition for forming a particle layer permeates too much into the voids, and a part of the surface of the porous layer, which forms the lower layer, is exposed, which causes blocking with other members.

[0072]

The volume average particle diameter (nm) of the particles is not particularly limited and can be appropriately selected according to a purpose, as long as the volume average particle diameter of the particles is larger than the average diameter (nm) of the voids in the porous layer. However, the volume average particle diameter of the particles is preferably 100 nm or more and 1,000 nm or less.

The volume average particle diameter of the particles is preferably 100 nm or more, because in this case, the voids in the porous layer are not easily blocked, the ion permeability is ensured, and it is possible to form a particle layer having excellent smoothness and blocking resistance.

The volume average particle diameter of the particles is preferably 1,000 nm or less, because in this case, it is possible to form a particle layer having even better smoothness.

[0073]

A method of measuring the volume average particle diameter of the particles is not particularly limited. For example, the volume average particle diameter may be measured by the following method.

[Method of Measuring Volume Average Particle Diameter of Particles]

For example, the particle diameter of the solid content can be measured by using a particle size distribution analyzer (NANOTRAC WAVE-UT151, manufactured by MicrotracBEL Corp.). [0074]

The particles are preferably inorganic particles or resin particles from the viewpoint of high electrical insulation.

The particles are not particularly limited and can be appropriately selected according to a purpose. For example, industrially synthesized or pulverized particles, ceramics, particles derived from mineral resources, and the like can be used.

[0075]

Examples of the inorganic particles include, but are not limited to, aluminum oxide, titanium dioxide, barium titanate, zirconium dioxide, nickel oxide, manganese oxide, vanadium dioxide, silicon dioxide, cordierite, steatite, forsterite, mullite, and zeolite.

Among these inorganic substances, high-purity synthetic products are preferred from the viewpoint of high electrical resistance and stability, and high-purity aluminum oxide (a- alumina) is particularly preferred.

These inorganic substances may be used alone or in combination of two or more types. [0076]

The inorganic particles and the resin particles may be appropriately synthesized, or a commercially available product may be used as the inorganic particles and the resin particles. Examples of commercially available products of the aluminum oxide include, but are not limited to, products of the trade names AKP-15, AKP-20, AKP-30, AKP-50, AKP-53, AKP- 700, AKP-3000, AA-03, AA-04, AA-05, AA-07, AA-1.5, AKP-G07, and AKP-G15 (all manufactured by Sumitomo Chemical Co., Ltd.), LS-235, LS-235C, LS-711, LS-711C, LS- 500, and LS-250 (all manufactured by Nippon Light Metal Co., Ltd.), SERATH 00610 and SERATH 02025 (both manufactured by Kinsei Matec Co., Ltd.), and TM-DA, TM-DAR, and TM-5D (all manufactured by Taimei Chemicals Co., Ltd.).

[0077]

Examples of the resin particles include, but are not limited to, acrylic resins, methacrylic resins, melamine resins, urethane resins, polycarbonate resins, epoxy resins, and fluororesins. These resins may be used alone or in combination of two or more types.

[0078]

Examples of commercially available products of the resin particles include, but are not limited to, products of the trade names EPOSTAR-MX50W, EPGSTAR-MX100W, EPOSTAR- MX200W, EPGSTAR-MX300W, EPOSTAR-SS, EPOSTAR-S, EPOSTAR-FS, and EPOSTAR-S6 (all manufactured by Nippon Shokubai Co., Ltd.), TECHPOLYMER SSX101 (manufactured by Sekisui Kasei Co., Ltd.), and FINE SPHERE FS-101, FS-102, FS-106, FS- 107, MG-155, MG-651, and PZP-1003 (manufactured by Nippon Paint Industrial Coatings, Co., Ltd.).

[0079]

[Average Thickness of Particle Layer] The average thickness of the particle layer is not particularly limited and can be appropriately selected according to a purpose. However, the average thickness is preferably 0.5 pm or more and 10 pm or less.

The average thickness of the particle layer is preferably 0.5 pm or more, because in this case, smoothness can be obtained and the porous layer can be covered to obtain an effect of suppressing blocking.

The average thickness of the particle layer is preferably 10 pm or less, because in this case, smoothness and high ion permeability can be ensured.

[0080]

A method of measuring the average thickness of the particle layer is not particularly limited. For example, the average thickness of the particle layer may be measured by the following method.

[Method of Measuring Average Thickness of Particle Layer]

The electrode is cut to obtain a square piece of 5 mm that includes the electrode base, the electrode composite layer, and the insulator layer. The square piece is immersed into a degassed resin (two-component mixture, 30-minute curing epoxy resin, manufactured by Devcon), and cured at 40°C in an oven for 12 hours. After the square piece of the electrode is sufficiently cured, the square piece is cut in the thickness direction by using a razor, ion milling, a micro-microtome, or the like, to prepare a cross-sectional sample. The cross section of the obtained cross-sectional sample is finished by using a cross section polisher (SM-09010, manufactured by JEOL, Ltd.) under conditions including an acceleration voltage of 5.0 kV and a beam current of 120 pA. Next, a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) is used to randomly capture a plurality of images of the cross section including an upper end and a lower end of the particle layer under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times. The plurality of obtained images are imported into TIFF images, and image analysis software (IMAGE- PRO PLUS, manufactured by Media Cybernetics) is used to calculate the area of the particle layer in the cross section and the length of the particle layer in the width direction in the cross section, that is, the length in the horizontal direction with respect to the electrode base, from the scale bar and the number of pixels obtained by the image analysis. The film thickness is calculated by dividing the area by the length in the width direction.

[0081]

<<<Dispersant for Forming Particle Layer>>>

The dispersant for forming a particle layer is not particularly limited, as long as the dispersant for forming a particle layer can disperse the particles in a dispersion medium. Examples of the dispersant for forming a particle layer include, but are not limited to, surfactants and polymer compounds. A copolymer including an adsorption group having high affinity for the particles and a dispersion group having high affinity for the dispersion medium can be used as the polymer compound.

[0082]

The dispersant for forming a particle layer may be appropriately synthesized, or a commercially available product may be used as the dispersant for forming a particle layer. Examples of the commercially available product of the dispersant for forming a particle layer include, but are not limited to, products of the trade names MEGAFACE F173, MEGAFACE F444, and MEGAFACE F470 (all manufactured by DIC Corporation), MALIALIM AAB- 0851, MALIALIM AFB-1521, MALIALIM AKM-0531, MALIALIM AWS-0851, MALIALIM HKM-50A, MALIALIM SC-0708A, MALIALIM SC-0505K, and MALIALIM SC-1015F (all manufactured by NOF Corporation), and DISPERBYK-103 and DISPERBYK- 2000 (both manufactured by BYK-Chemie GmbH).

[0083]

The particle layer can be prepared by using a liquid composition for forming a particle layer. Note that a specific method of preparing the particle layer will be described later.

[0084]

<<<Liquid Composition for Forming Particle Layer>>>

The liquid composition for forming a particle layer (maybe also referred to as “particle layer forming liquid composition”) contains particles, and if desired, may contain a dispersant for forming a particle layer, a dispersion medium, a binder, and an antifoaming agent.

Note that the particles and the dispersant for forming a particle layer are the same as those described in the section <<Particle Layer>> above, and thus, description thereof will be omitted.

[0085]

- Binder -

The binder in the liquid composition for forming a particle layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include, but are not limited to, poly vinylidene fluoride, styrene-butadiene rubber, and acrylic resins.

These binders may be used alone or in combination of two or more types. Further, the binder may be dissolved or dispersed in the liquid composition for forming a particle layer.

Note that a precursor of a binder may be used instead of the binder. Examples of the precursor of the binder include, but are not limited to, monomers. A liquid composition containing such a monomer and, if desired, further containing a polymerization initiator may be applied onto an absorption medium (may be referred to as a base hereinafter), and then, heated or irradiated with light to polymerize the monomer and improve the strength of a functional film.

[0086]

- Dispersion Medium for Forming Particle Layer - The dispersion medium for forming a particle layer is added as a dispersion solvent for inorganic particles in the liquid composition for forming a particle layer or as an adjustment factor for liquid physical properties.

The content of the dispersion medium for forming a particle layer in the liquid composition for forming a particle layer is not particularly limited and can be appropriately selected according to a purpose.

The components of the dispersion medium for forming a particle layer are not particularly limited and can be appropriately selected according to a purpose, but an aqueous solvent or a non-aqueous solvent is preferred.

[0087]

The aqueous solvent is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include, but are not limited to, water and a mixture of water and a polar solvent.

Examples of the polar solvent include, but are not limited to, methanol, ethanol, propanol, butanol, pentanol, hexanol, ethylene glycol, propylene glycol, hexylene glycol, N-methyl-2- pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone, and tetrahydrofuran (THF). These polar solvents may be used alone or in combination of two or more types.

[0088]

The non-aqueous solvent is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include, but are not limited to, lactams, alcohols, sulfoxides, esters, ethers, glycols, and ketones.

Examples of the lactams include, but are not limited to, l-methyl-2-pyrrolidone and 2- pyrrolidone.

Examples of the alcohols include, but are not limited to, isopropyl alcohol, butanol, and diacetone alcohol.

Examples of the sulfoxides include, but are not limited to, dimethyl sulfoxide.

Examples of the esters include, but are not limited to, ethyl acetate, butyl acetate, ethyl lactate, and ethylene glycol diacetate.

Examples of the ethers include, but are not limited to, dipropylene glycol monomethyl ether and propylene glycol monopropyl ether.

Examples of the glycol include, but are not limited to, propylene glycol, ethylene glycol, triethylene glycol, and hexylene glycol.

Examples of the ketones include, but are not limited to, methyl ethyl ketone (MEK), diisobutyl ketone, 2-butanone, 2-pentanone, and diacetone alcohol.

These non-aqueous type solvents may be used alone or in combination of two or more types. [0089]

A method of preparing the liquid composition for forming a particle layer is not particularly limited and can be appropriately selected according to a purpose. Examples of the method include, but are not limited to, a method of stirring in advance a solvent for forming a particle layer, particles, and a dispersant, and then, using a dispersing machine to obtain a particle dispersion liquid. The dispersing machine is not particularly limited, but examples thereof include homomixers, homogenizers, ultrasonic dispersing machines, ball mills, bead mills, and cavitation mills.

[0090]

A method of manufacturing an electrode of the present embodiment is a method of manufacturing an electrode including a particle layer forming step. The particle layer forming step includes a step of applying a liquid composition for forming a particle layer in which a liquid composition for forming a particle layer is applied onto a porous layer. The porous layer has a backbone and voids and is formed on an electrode composite layer provided on a base.

Note that the “particle layer” in the particle layer forming step, and the “base,” the “electrode composite layer,” the “porous layer,” the “liquid composition for forming a particle layer” and the like in the step of applying a liquid composition for forming a particle layer are similar to those described in the section (Electrode) above, and thus, overlapping parts of the description will be omitted.

[0091]

In other words, a method of manufacturing an electrode of the present embodiment includes a particle layer forming step, and if desired, may also include an electrode composite layer forming step, a porous layer forming step, and other steps.

The method of manufacturing an electrode can be suitably implemented by using an electrode manufacturing apparatus.

The electrode manufacturing apparatus according to the present embodiment includes a particle layer forming means, and if desired, may also include an electrode composite layer forming means, a porous layer forming means, and other means.

[0092]

<<Electrode Composite Layer Forming Step and Electrode Composite Layer Forming Means >>

The electrode composite layer forming step is a step of applying a liquid composition for forming an electrode composite layer onto a base to form an electrode composite layer. The electrode composite layer forming step can be suitably implemented by the electrode composite layer forming means.

The electrode composite layer forming means is a means used for applying a liquid composition for forming an electrode composite layer onto a base to form an electrode composite layer.

The electrode composite layer forming means is not particularly limited, as long as the electrode composite layer forming means can apply the liquid composition for forming an electrode composite layer onto a base. However, examples of the electrode composite layer forming means include, but are not limited to, printing machines employing a spray method, a dispenser method, a die coating method, a dip coating method, a curtain coating method, and an inkjet method.

[0093]

The electrode composite layer forming step and the electrode composite layer forming means preferably include a step of heating and drying the liquid composition for forming an electrode composite layer, and a means used for heating and drying the liquid composition for forming an electrode composite layer, respectively.

The step of heating and drying the liquid composition for forming an electrode composite layer is a step of drying the liquid composition for forming an electrode composite layer, after the liquid composition for forming an electrode composite layer is applied onto a base.

The means used for heating and drying the liquid composition for forming an electrode composite layer is a means that dries the liquid composition for forming an electrode composite layer that is applied onto a base.

[0094]

The means used for heating and drying the liquid composition for forming an electrode composite layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include a resistance heater, an infrared heater, and a fan heater. Among these heaters, non-contact heaters are preferably used, because in this case, an application surface to which the liquid composition for forming an electrode composite layer is applied can be uniformly heated and dried.

Specific examples of the step of heating and drying the liquid composition for forming an electrode composite layer include, but are not limited to, a method of using a resistance heater, an infrared heater, a fan heater, and the like, to heat the application surface, and a method of drying from a back side of the application surface by using a hot plate, a drum heater, and the like.

[0095]

The heating temperature in the step of heating and drying the liquid composition for forming an electrode composite layer is not particularly limited and can be appropriately selected according to a purpose. However, the heating temperature is preferably 70°C or higher and 150°C or lower.

The heating temperature is preferably 70°C or higher, because in this case, it is possible to sufficiently dry the liquid composition for forming an electrode composite layer.

The heating temperature is preferably 150°C or lower, because in this case, the base and the active material contained in the electrode composite layer can be prevented from denaturing. [0096]

<<Porous Layer Forming Step and Porous Layer Forming Means>>

The porous layer forming step is a step of forming, on the electrode composite layer, a porous layer having a backbone and voids. The porous layer forming step preferably includes a step of applying a liquid composition for forming a porous layer, an irradiation step, and a step of heating the liquid composition for forming a porous layer. The porous layer forming means is means used for forming, on the electrode composite layer, a porous layer having a backbone and voids. The porous layer forming means preferably includes a means used for applying a liquid composition for forming a porous layer, an irradiation means, and a means used for heating the liquid composition for forming a porous layer.

The porous layer forming step can be suitably implemented by the porous layer forming means. The step of applying a liquid composition for forming a porous layer can be suitably implemented by the means used for applying a liquid composition for forming a porous layer. The irradiation step can be suitably implemented by the irradiation means. The step of heating the liquid composition for forming a porous layer can be suitably implemented by the means used for heating the liquid composition for forming a porous layer.

[0097]

- Step of Applying Liquid Composition for Forming Porous Layer and Means Used for Applying Liquid Composition for Forming Porous Layer -

The step of applying a liquid composition for forming a porous layer is a step of applying a liquid composition for forming a porous layer onto the electrode composite layer.

The means used for applying a liquid composition for forming a porous layer is a means that applies a liquid composition for forming a porous layer onto the electrode composite layer. The means used for applying a liquid composition for forming a porous layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include a printing device utilizing a spin coating method, a casting method, a microgravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a slit coating method, a capillary coating method, a spray coating method, a nozzle coating method, a gravure printing method, a screen printing method, a flexographic printing method, an offset printing method, a reverse printing method, or an inkjet printing method.

[0098]

- Irradiation Step and Irradiation Means -

The irradiation step is a step of irradiating the liquid composition for forming a porous layer applied onto the electrode composite layer with light.

The irradiation means is a means that irradiates the liquid composition for forming a porous layer applied onto the electrode composite layer with light.

The light is preferably formed by active energy rays.

[0099]

The active energy rays used in the irradiation step and by the irradiation means are not particularly limited and can be appropriately selected according to a purpose, as long as the active energy rays can provide the energy used for promoting the polymerization reaction of the polymerizable compound in the liquid composition for forming a porous layer. Examples of the active energy rays include, but are not limited to, ultraviolet rays (UV), an electron beam (EB), and X-rays. Among these active energy rays, ultraviolet rays (UV) are preferred to obtain excellent curability.

The light source for the ultraviolet rays is not particularly limited and can be appropriately selected in accordance with the absorption spectrum of the polymerizable compound and the like. Examples of the light source include, but are not limited to, low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, hot cathode tubes, cold cathode tubes, and UV-LEDs.

[0100]

When using an active energy ray irradiation device that emits the active energy rays as the irradiation means, the irradiation intensity may decrease and side reactions may occur due to gases in the atmosphere such as oxygen. Therefore, it is desirable to provide equipment and the like that can perform irradiation in an inert gas or vacuum.

[0101]

The illumination intensity (also referred to as lamp intensity, lamp illuminance, and the like) in the irradiation step is not particularly limited and can be appropriately selected according to a purpose. However, from the viewpoint of reactivity of the liquid composition for forming a porous layer, the illumination intensity is preferably 1.0 W/cm² or more.

[0102]

- Step of Heating Liquid Composition for Forming Porous Layer and Means Used for Heating Liquid Composition for Forming Porous Layer -

The step of heating the liquid composition for forming a porous layer is a step of heating a solvent for forming a porous layer to remove the solvent.

The means used for heating the liquid composition for forming a porous layer is a means that heats a solvent for forming a porous layer to remove the solvent.

As the means used for heating the liquid composition for forming a porous layer, a means similar to the means used for heating and drying the liquid composition for forming an electrode composite layer described in the section <<Electrode Composite Layer Forming Step and Electrode Composite Layer Forming Means>> above can be used.

[0103]

The heating temperature in the step of heating the liquid composition for forming a porous layer is not particularly limited and can be appropriately selected according to a purpose. However, the heating temperature is preferably 70°C or higher and 150°C or lower.

The heating temperature is preferably 70°C or higher, because in this case, porogen can be sufficiently removed and the compression resistance is improved by the heating.

The heating temperature is preferably 150°C or lower, because in this case, bumping of the porogen can be suppressed, pinholes can be prevented from forming, and the insulation properties are improved.

[0104]

In the porous layer forming step, by irradiating the liquid composition for forming a porous layer with active energy rays, a polymerization reaction of the polymerizable compound in the liquid composition for forming a porous layer is induced, and preferably, polymerization- induced phase separation is induced. In other words, a cured product obtained by the polymerization reaction is preferably formed via spinodal decomposition caused by irradiating, with active energy rays, a liquid composition for forming a porous layer, the liquid composition containing the polymerizable compound and a porogen forming a liquid solvent that can dissolve the polymerizable compound and in which the polymerizable compound can separate by phase separation as the polymerization progresses.

Here, the term “spinodal decomposition” refers to the formation of two phases (a porogen phase and a polymerizable compound phase) having different compositions from substance diffusion against a concentration gradient without forming nuclei.

[0105]

An example of a mechanism by which the porous layer is formed will be illustrated below. In a process of forming the porous layer, before polymerization, a mixed phase (a mixed phase containing a polymerizable compound, a polymerization initiator, and other additives) and a porogen solvent (a water phase or an organic solvent phase) form a uniformly mixed phase. When the polymerization starts, the two homogeneous components (the polymerizable compound and the porogen solvent) spontaneously gradually separate on the microscopic (fine) scale from an early stage to a late stage of the polymerization and are fixed, and thus, a continuous backbone (cured product) is formed. Subsequently, after heating, continuous voids are formed in a portion where the porogen is present before heating, so that a porous layer is formed that has a two-phase continuous structure in which both the backbone and the voids are continuous.

[0106]

<<Particle Layer Forming Step and Particle Layer Forming Means >>

The particle layer forming step is a step of applying a liquid composition for forming a particle layer onto the porous layer to form a particle layer. The particle layer forming step preferably includes a step of applying a liquid composition for forming a particle layer and a step of heating the liquid composition for forming a particle layer.

The particle layer forming means is a means that forms a particle layer by applying a liquid composition for forming a particle layer onto the porous layer. The particle layer forming means preferably includes a means used for applying a liquid composition for forming a particle layer and a means used for heating the liquid composition for forming a particle layer. The particle layer forming step can be suitably implemented by the particle layer forming means. The step of applying a liquid composition for forming a particle layer can be suitably implemented by the means used for applying a liquid composition for forming a particle layer. The step of heating a liquid composition for forming a particle layer can be suitably implemented by the means used for heating the liquid composition for forming a particle layer.

[0107] - Step of Applying Liquid Composition for Forming Particle Layer and Means Used for Applying Liquid Composition for Forming Particle Layer -

The step of applying a liquid composition for forming a particle layer is a step of applying a liquid composition for forming a particle layer onto the porous layer.

The means used for applying a liquid composition for forming a particle layer is a means that applies a liquid composition for forming a particle layer onto the porous layer.

The means used for applying the liquid composition for forming a particle layer is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include a means similar to the means used for applying the liquid composition for forming a porous layer described in the section <<Porous Layer Forming Step and Porous Layer Forming Means >> above.

[0108]

- Step of Heating Liquid Composition for Forming Particle Layer and Means Used for Heating Liquid Composition for Forming Particle Layer -

The step of heating the liquid composition for forming a particle layer is a step of heating a solvent for forming a particle layer (maybe also referred to as “particle layer forming solvent”) to remove the solvent.

The means used for heating the liquid composition for forming a particle layer is a means that heats a solvent for forming a particle layer to remove the solvent.

As the means used for heating the liquid composition for forming a particle layer, a means similar to the means used for heating and drying the liquid composition for forming an electrode composite layer described in the section <<Electrode Composite Layer Forming Step and Electrode Composite Layer Forming Means>> above can be used.

[0109]

After the electrode composite layer forming step, the porous layer forming step, and the particle layer forming step, the electrode may be cut into a desired size by punching processing or the like to form the electrode.

[0110]

The particle layer forming step may be performed after the porous layer forming step, or may be performed simultaneously with the porous layer forming step.

Note that a method in which the particle layer forming step is performed after the porous layer forming step is a so-called wet-on-dry method. A method in which the particle layer forming step and the porous layer forming step are performed simultaneously or in parallel is a so- called wet-on-wet method.

[0111]

The step of heating the liquid composition for forming a porous layer is preferably performed after the irradiation step and before the particle layer forming step. The step of heating the liquid composition for forming a porous layer is preferably performed simultaneously with the particle layer forming step or after the particle layer forming step. More preferably, the step of heating the liquid composition for forming a porous layer and the step of heating the liquid composition for forming a particle layer are performed simultaneously.

[0112]

More specifically, any of the following patterns 1 to 4 may be used.

[0113]

- Pattern 1 (Wet-on-Dry) Method -

Pattern 1 is a pattern in which the step of heating the liquid composition for forming a porous layer is performed after the irradiation step and before the particle layer forming step.

In other words, pattern 1 is a pattern in which the irradiation step, the step of heating the liquid composition for forming a porous layer, and the particle layer forming step are performed in this order.

[0114]

- Pattern 2 (Wet-on-Wet) Method -

Pattern 2 is a pattern in which the step of heating the liquid composition for forming a porous layer is performed simultaneously with the step of heating the liquid composition for forming a particle layer.

In other words, pattern 2 is a pattern in which, after the irradiation step and the step of applying a liquid composition for forming a particle layer are performed in this order, the step of heating the liquid composition for forming a porous layer and the step of heating the liquid composition for forming a particle layer are performed simultaneously.

[0115]

- Pattern 3 (Wet-on-Wet) Method -

Pattern 3 is a pattern in which the particle layer forming step is performed in parallel with the step of heating the liquid composition for forming a porous layer.

In other words, pattern 3 is a pattern in which, after the irradiation step, the step of applying a liquid composition for forming a particle layer is performed while performing the step of heating the liquid composition for forming a porous layer, to perform the step of heating the liquid composition for forming a porous layer and the step of heating the liquid composition for forming a particle layer in parallel.

[0116]

- Pattern 4 (Wet-on-Wet) Method -

Pattern 4 is a pattern in which the step of heating the liquid composition for forming a porous layer is performed after the particle layer forming step.

In other words, pattern 4 is a pattern in which, after the irradiation step, the step of applying a liquid composition for forming a particle layer and the step of heating the liquid composition for forming a particle layer are performed in this order, and then, the step of heating the liquid composition for forming a porous layer is performed.

[0117]

Embodiments of a method of manufacturing an electrode and an electrode manufacturing apparatus according to the present embodiment will be described below. [0118]

[Embodiment for Forming Electrode Composite Layer by Direct Application of Liquid Composition for Forming Electrode Composite Layer onto Base]

FIG. 3 is a schematic diagram illustrating an example of an electrode manufacturing apparatus according to the present embodiment. More specifically, FIG. 3 illustrates an example of an apparatus for manufacturing an electrode composite layer by using the above-described liquid composition for forming an electrode composite layer.

A liquid composition 12A for forming an electrode composite layer is stored in a tank 307 of a liquid discharge device 300, and is supplied from the tank 307 to a liquid discharge head 306 via a tube 308. Note that the number of liquid discharge devices is not limited to one, and may be two or more.

When manufacturing an electrode composite layer, a base 11 is placed on a stage 310, and then, droplets of the liquid composition 12A for forming an electrode composite layer are discharged from the liquid discharge head 306 onto the base 11. At this time, the stage 310 may move, and the liquid discharge head 306 may move. The discharged liquid composition 12A for forming an electrode composite layer forms an electrode composite layer 12.

Further, the liquid discharge device 300 may include a mechanism for capping a nozzle for the purpose of preventing drying when the liquid composition 12A for forming an electrode composite layer is not discharged from the liquid discharge head 306.

[0119]

FIG. 4 is a schematic diagram illustrating another example of the electrode manufacturing apparatus of the present embodiment. More specifically, FIG. 4 illustrates another example of the apparatus for manufacturing an electrode composite layer by using the above-described liquid composition for forming an electrode composite layer.

The electrode manufacturing apparatus includes a printer 10 that applies a liquid composition for forming an electrode composite layer onto a base 4 to form a liquid composition layer for forming an electrode composite layer, and if desired, the electrode manufacturing apparatus includes a heater 30. The electrode manufacturing apparatus includes a conveyor 5 that conveys the base 4. The conveyor 5 conveys the base 4 to the printer 10 and the heater 30 in this order at a speed set in advance.

[0120]

- Printer 10 -

The printer 10 includes a printing device la, which is an example of the electrode composite layer forming means that applies a liquid composition for forming an electrode composite layer onto the base 4 to form an electrode composite layer, a storage container lb that accommodates the liquid composition for forming an electrode composite layer, and a supply tube 1c that supplies a liquid composition 7 for forming an electrode composite layer stored in the storage container lb to the printing device la.

The storage container lb accommodates the liquid composition 7 for forming an electrode composite layer. The printer 10 discharges the liquid composition 7 for forming an electrode composite layer from the printing device la to apply the liquid composition 7 for forming an electrode composite layer onto the base 4, to form a liquid composition layer for forming an electrode composite layer as a thin film. The storage container lb may be integrally formed with the electrode manufacturing apparatus, or may be removable from the electrode manufacturing apparatus. Further, the storage container lb may be a container used for addition to a storage container integrally formed with the electrode manufacturing apparatus or a storage container removable from the electrode manufacturing apparatus.

The storage container lb and the supply tube 1c can be freely selected, as long as the storage container lb and the supply tube 1c can stably store and supply the liquid composition 7 for forming an electrode composite layer.

[0121]

- Heater 30 -

As illustrated in FIG. 4, the heater 30 includes a heating device 3a. The heating device 3a performs a heating and drying step of heating the liquid composition layer for forming an electrode composite layer formed by the printer 10, to dry the remaining liquid and remove the solvent. Thus, an electrode composite layer can be formed. The heater 30 may remove the liquid under reduced pressure.

The heating temperature and time can be appropriately selected in accordance with the boiling point of the liquid contained in the liquid composition layer for forming an electrode composite layer and the thickness of the film to be formed.

[0122]

FIG. 5 is a schematic diagram illustrating still another example of the electrode manufacturing apparatus of the present embodiment.

A liquid discharge device 300' can control a pump 3101, a valve 311, and a valve 312 to circulate the liquid composition for forming an electrode composite layer in the liquid discharge head 306, the tank 307, and the tube 308.

The liquid discharge device 300' includes an external tank 313. When the amount of the liquid composition for forming an electrode composite layer in the tank 307 decreases, the liquid discharge device 300' controls the pump 3101, the valve 311, the valve 312, and a valve 314 to supply the liquid composition for forming an electrode composite layer from the external tank 313 to the tank 307.

By using the above-described electrode manufacturing apparatus, the liquid composition for forming an electrode composite layer can be discharged to a targeted location of a base. [0123]

FIG. 6 is a schematic diagram illustrating an example of a method of manufacturing an electrode of the present embodiment. More specifically, FIG. 6 is a schematic diagram illustrating an example of a method of manufacturing an electrode composite layer of the present embodiment. The method of manufacturing an electrode includes a step of sequentially discharging the liquid composition 12A for forming an electrode composite layer onto the base 11 by using a liquid discharge device.

First, the base 11 having an elongated shape is prepared. The base 11 is wound around a tubular core and set on an unwinding roller 304 and a wind-up roller 305 so that a side on which the electrode composite layer 12 is to be formed faces upward in FIG. 6. Here, the unwinding roller 304 and the wind-up roller 305 rotate counterclockwise in FIG. 6 to convey the base 11 from right to left in FIG. 6. The liquid discharge head 306 disposed above the base 11 between the unwinding roller 304 and the wind-up roller 305 discharges droplets of the liquid composition 12A for forming an electrode composite layer onto the base 11 that is sequentially conveyed, similarly to FIG. 3.

The liquid discharge head 306 may be provided as a plurality of liquid discharge heads 306 in a direction substantially parallel or substantially perpendicular to the conveyance direction of the base 11.

Next, the base 11 onto which the droplets of the liquid composition 12A for forming an electrode composite layer are discharged is conveyed by the unwinding roller 304 and the wind-up roller 305 to a heating mechanism 309 employed as a heating and drying means, and the electrode composite layer 12 is formed.

The heating mechanism 309 may be arranged above or below the base 11, or a plurality of heating mechanisms 309 may be provided.

[0124]

Further, as illustrated in FIG. 7, a liquid discharge device 300A' and a liquid discharge device 300B' may be used in combination. That is, a tank may supply the liquid composition 12A for forming an electrode composite layer from an external tank 313 A and an external tank 313B connected to a tank 307A and a tank 307B, and the liquid discharge head may include a plurality of heads including a head 306A and a head 306B. Accordingly, a tube 308 A and a tube 3O8B, a valve 311A and a valve 31 IB, a valve 312A and a valve 312B, a valve 314A and a valve 314B, and a pump 310A and a pump 310B may be provided.

[0125]

[Embodiment for Forming Electrode Composite Layer by Indirect Application of Liquid Composition for Forming Electrode Composite Layer onto Base]

FIG. 8 is a configuration diagram illustrating an example of a printer using a drum-shaped intermediate transfer body as the electrode manufacturing apparatus according to the present embodiment.

A printer 400' is an inkjet printer that transfers the liquid composition layer for forming an electrode composite layer or the electrode composite layer via an intermediate transfer body

4001, to form an electrode composite layer on the base.

[0126]

The printer 400' includes an inkjet portion 420, a transfer drum 4000, a preprocessing unit

4002, an absorption unit 4003, a heating unit 4004, and a cleaning unit 4005. The inkjet portion 420 includes a head module 422 holding a plurality of heads 101. Each of the heads 101 discharges the liquid composition for forming an electrode composite layer onto the intermediate transfer body 4001 supported by the transfer drum 4000, and forms a liquid composition layer for forming an electrode composite layer on the intermediate transfer body 4001. Each of the heads 101 is a line head, and has nozzles arranged in a range covering the width of a recording area of a base having a maximum usable size. The head 101 includes, on a lower surface thereof, a nozzle surface in which a nozzle is formed, and the nozzle surface faces the front surface of the intermediate transfer body 4001 with a small gap interposed therebetween. In the present embodiment, the intermediate transfer body 4001 is configured to circulate and move on a circular trajectory, and thus, the plurality of heads 101 are arranged radially.

[0127]

The transfer drum 4000 faces an impression cylinder 621 and forms a transfer nip portion. For example, before the heads 101 discharge the liquid composition for forming an electrode composite layer, the preprocessing unit 4002 applies, onto the intermediate transfer body 4001, a reactive liquid to increase the viscosity of the liquid composition for forming an electrode composite layer.

The absorption unit 4003 absorbs a liquid component from the liquid composition layer for forming an electrode composite layer present on the intermediate transfer body 4001, before the liquid composition layer for forming an electrode composite layer is transferred.

The heating unit 4004 heats the liquid composition layer for forming an electrode composite layer on the intermediate transfer body 4001, before the liquid composition layer for forming an electrode composite layer is transferred. By heating the liquid composition layer for forming an electrode composite layer, the liquid composition layer for forming an electrode composite layer is dried to form the electrode composite layer. Further, the organic solvent is removed to improve the transferability to the base.

The cleaning unit 4005 cleans the intermediate transfer body 4001, after the liquid composition layer for forming an electrode composite layer is transferred, to remove foreign substances such as dust and the liquid composition for forming an electrode composite layer remaining on the intermediate transfer body 4001.

[0128]

The outer circumferential surface of the impression cylinder 621 is in pressure contact with the intermediate transfer body 4001, and when the base passes through the transfer nip portion between the impression cylinder 621 and the intermediate transfer body 4001, the liquid composition for forming an electrode composite layer or the electrode composite layer on the intermediate transfer body 4001 is transferred to the base. Note that the impression cylinder 621 may be configured to include, on the outer circumferential surface thereof, at least one grip mechanism for holding a tip end portion of the base.

[0129] A printer 400" illustrated in FIG. 9 is an inkjet printer that transfers the liquid composition for forming an electrode composite layer or the electrode composite layer via an intermediate transfer belt 4006, to form an electrode composite layer on a base.

The printer 400" discharges droplets of the liquid composition from a plurality of heads 401 provided in the inkjet portion 420 to form a liquid composition layer for forming an electrode composite layer on an outer circumferential surface of the intermediate transfer belt 4006. The liquid composition layer for forming an electrode composite layer formed on the intermediate transfer belt 4006 is heated and dried by a heating unit 4007 to form an electrode composite layer, which forms a film on the intermediate transfer belt 4006.

The liquid composition layer for forming an electrode composite layer present as a film on the intermediate transfer belt 4006 is transferred to the base in the transfer nip portion where the intermediate transfer belt 4006 faces a transfer roller 622. After the liquid composition layer for forming an electrode composite layer is transferred, the surface of the intermediate transfer belt 4006 is cleaned by a cleaning roller 4008.

The intermediate transfer belt 4006 is spanned over a drive roller 4009a, a counter roller 4009b, a plurality of (four in the present example) shape-maintaining rollers including a shape-maintaining roller 4009c, a shape-maintaining roller 4009d, a shape-maintaining roller 4009e, and a shape-maintaining roller 4009f, and a plurality of (four in the present example) support rollers 4009g, and moves in the direction of the arrows in FIG. 9. The support rollers 4009g are provided to face the heads 401 and maintain the intermediate transfer belt 4006 in a tension state when droplets of the liquid composition for forming an electrode composite layer are discharged from the heads 401.

[0130]

When forming a porous layer in the present embodiment, a configuration may be employed in which the “liquid composition for forming an electrode composite layer” in the sections [Embodiment for Forming Electrode Composite Layer by Direct Application of Liquid Composition for Forming Electrode Composite Layer onto Base] and [Embodiment for Forming Electrode Composite Layer by Indirect Application of Liquid Composition for Forming Electrode Composite Layer onto Base] above is replaced with a “liquid composition for forming a porous layer,” and an “active energy ray irradiation device” is provided before the base is subjected to the heating mechanism.

When forming a particle layer in the present embodiment, a configuration may be employed in which the “liquid composition for forming an electrode composite layer” in the sections [Embodiment for Forming Electrode Composite Layer by Direct Application of Liquid Composition for Forming Electrode Composite Layer onto Base] and [Embodiment for Forming Electrode Composite Layer by Indirect Application of Liquid Composition for Forming Electrode Composite Layer onto Base] above is replaced with a “liquid composition for forming a particle layer.” [0131] (Non-Aqueous Power Storage Element) A non-aqueous power storage element of the present embodiment preferably includes an electrode, a non-aqueous electrolyte, a separator, and an exterior casing.

Note that the electrode is the same as the electrode described in the section (Electrode) above, and thus, description thereof will be omitted. Further, the separator is different from the separator described in the section < Insulator Lay er > above, and is provided separately from the insulator layer.

[0132]

<Non-Aqueous Electrolyte>

The non-aqueous electrolyte is not particularly limited, can be appropriately selected according to a purpose, and examples thereof include a non-aqueous electrolyte liquid. The non-aqueous electrolyte liquid refers to an electrolyte liquid in which an electrolyte salt is dissolved in a non-aqueous solvent.

[0133]

<<Non- Aqueous Solvent>>

The non-aqueous solvent is not particularly limited and can be appropriately selected according to a purpose, as long as the non-aqueous solvent can dissolve the electrolyte salt. However, the non-aqueous solvent is preferably an aprotic organic solvent.

[0134]

Examples of the aprotic organic solvent include, but are not limited to, carbonate -based organic solvents such as chain carbonates and cyclic carbonates. Among these organic solvents, chain carbonates are preferred for providing high dissolving power for the electrolyte salt.

Examples of the chain carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC).

Examples of the cyclic carbonates include, but are not limited to, propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC).

[0135]

Examples of non-aqueous solvents other than the carbonate-based organic solvents include, but are not limited to, ester-based organic solvents such as cyclic esters and chain esters, and ether-based organic solvents such as cyclic ethers and chain ethers.

Examples of the cyclic esters include, but are not limited to, y-butyrolactone (yBL), 2-methyl- y-butyrolactone, acetyl-y-butyrolactone, and y-valerolactone.

Examples of the chain esters include, but are not limited to, propionic acid alkyl esters, malonic acid dialkyl esters, acetic acid alkyl esters (for example, methyl acetate (MA) and ethyl acetate), and formic acid alkyl esters (for example, methyl formate (MF) and ethyl formate).

Examples of the cyclic ethers include, but are not limited to, tetrahydrofuran, alkyltetrahydrofuran, alkoxy tetrahydrofuran, dialkoxy tetrahydrofuran, 1,3 -dioxolane, alkyl - 1,3-dioxolane, and 1,4-dioxolane. Examples of the chain ethers include, but are not limited to, 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

[0136]

These non-aqueous solvents may be used alone or in combination of two or more types. [0137]

The content of the chain carbonates is preferably 40 mass% or more, and more preferably 50 mass% or more, with respect to the total amount of the non-aqueous solvent. The content of the chain carbonates is preferably 40 mass% or more with respect to the total amount of the non-aqueous solvent, because in this case, it is possible to improve the permeability of the non-aqueous electrolyte liquid into the porous layer and the ion diffusibility.

[0138]

<<Electrolyte Salt>>

The electrolyte salt is not particularly limited and can be appropriately selected according to a purpose, as long as the electrolyte salt has high ionic conductivity and can be dissolved in the non-aqueous solvent.

Examples of a cation component included in the electrolyte salt include, but are not limited to, alkali metal salts.

The alkali metal salts are not particularly limited and can be appropriately selected according to a purpose. Examples of the alkali metal salts include, but are not limited to, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethylsulfonyl)imide, and lithium bis(pentafluoroethylsulfonyl)imide.

These alkali metal salts may be used alone or in combination of two or more types. [0139]

The concentration of the electrolyte salt in the non-aqueous electrolyte liquid is not particularly limited and can be appropriately selected according to a purpose. However, the concentration is preferably 1 mol/L or more and 4 mol/L or less.

[0140]

The separator may be provided between the negative electrode and the positive electrode, if desired, to prevent a short circuit between the negative electrode and the positive electrode. The separator has ion permeability and preferably has insulating properties not including electron conductivity.

Note that the separator is different from the separator described in the section < Insulator Layer> above, and is provided separately from the insulator layer.

[0141]

The material of the separator is not particularly limited and can be appropriately selected according to a purpose. The structure of the separator is not particularly limited and can be appropriately selected according to a purpose. The structure may be a single-layer structure or a laminated structure. The size of the separator is not particularly limited and can be appropriately selected according to a purpose, as long as the separator can be used in the non-aqueous power storage element.

The material of the separator is not particularly limited and can be appropriately selected according to a purpose. Examples of the material include, but are not limited to, types of paper such as kraft paper, vinylon mixed paper, synthetic pulp mixed paper, polyolefin nonwoven fabrics such as cellophane, grafted polyethylene films, and polypropylene melt flow nonwoven fabrics, polyamide nonwoven fabrics, glass fiber nonwoven fabrics, microporous polyethylene films, and microporous polypropylene films.

[0142]

< Exterior Casing >

The exterior casing is not particularly limited, as long as the exterior casing can seal the electrode, the non-aqueous electrolyte, and the separator.

[0143]

The shape of the non-aqueous power storage element is not particularly limited, and examples thereof include a laminate type in which flat electrodes are laminated, a cylinder type in which sheet electrodes and a separator are formed in a spiral shape, a cylinder type having an inside-out structure in which pellet electrodes and a separator are combined, and a coin type in which pellet electrodes and a separator are laminated.

[0144]

(Method of Manufacturing Non-Aqueous Power Storage Element and Non-Aqueous Power Storage Element Manufacturing Apparatus)

A method of manufacturing a non-aqueous power storage element of the present embodiment includes an electrode manufacturing step of manufacturing an electrode by the abovedescribed method of manufacturing an electrode, and an element formation step of manufacturing a non-aqueous power storage element by using the electrode, and further includes other steps, if desired.

A non-aqueous power storage element manufacturing apparatus of the present embodiment includes an electrode manufacturing portion that manufactures an electrode by the abovedescribed electrode manufacturing apparatus, and an element formation portion that manufactures a non-aqueous power storage element by using the electrode, and further includes other means, if desired.

[0145]

<<Electrode Manufacturing Step and Electrode Manufacturing Portion>>

The electrode manufacturing step includes the electrode composite layer forming step, the porous layer forming step, and the particle layer forming step described above in the method of manufacturing an electrode, and if desired, includes other steps such as an electrode processing step. The electrode manufacturing portion includes the storage container, the electrode composite layer forming means, the porous layer forming means, and the particle layer forming means described above in the electrode manufacturing apparatus, and if desired, includes other means such as an electrode processing means.

By using the electrode manufacturing step and the electrode manufacturing portion, it is possible to manufacture an electrode including an electrode base, an electrode composite layer on the electrode base, a porous layer on the electrode composite layer, and a particle layer on the porous layer.

[0146]

<<Element Formation Step and Element Formation Portion>>

The element formation step is a step of manufacturing a non-aqueous power storage element by using the electrode.

The element formation portion is a means that manufactures a non-aqueous power storage element by using the electrode.

The method of manufacturing a non-aqueous power storage element by using an electrode is not particularly limited, and any known method of manufacturing a non-aqueous power storage element can be appropriately selected according to a purpose. Examples of the method include, but are not limited to, a method of forming a non-aqueous power storage element by using at least one process among installing a counter electrode, winding or laminating the counter electrode, and accommodating the counter electrode in a container. Note that the element formation step may not include all the steps of forming an element, and may include a part of the steps of forming an element.

[0147]

<<Electrode Processing Step and Electrode Processing Portion>>

The electrode processing portion is a means that processes the electrode on which the electrode composite layer is formed, downstream of the particle layer forming means. The electrode processing portion may perform at least one process among cutting, folding, and bonding. For example, the electrode processing portion may cut the electrode and prepare a laminated body of electrodes. The electrode processing portion may wind or laminate electrodes, for example.

The electrode processing portion includes, for example, an electrode processing device, and may cut, zig zag-fold, laminate, and wind the electrode, in accordance with a targeted aspect of the battery.

The electrode processing step performed by the electrode processing portion is, for example, a step of processing the electrode downstream of the particle layer forming step. The electrode processing step may include at least one step among a cutting step, a folding step, and a bonding step.

[0148]

The applications of the non-aqueous power storage element are not particularly limited and examples thereof include laptop computers, smart devices, electronic book players, portable facsimile machines, portable copiers, portable printers, headphone stereos, video movie recorders, liquid crystal display televisions, handy cleaners, portable CD players, mini disk players, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power sources, motors, lighting equipment, toys, game machines, clocks, stroboscopes, cameras, and moving bodies such as vehicles. Among these applications, moving bodies are preferred.

Examples of the moving bodies include, but are not limited to, a standard vehicle, a special large vehicle, a special small vehicle, a truck, a large motorcycle, and a standard motorcycle. [0149]

[Moving Body]

FIG. 10 illustrates an example of a moving body including the non-aqueous power storage element of the present embodiment.

For example, a moving body 550 is an electric vehicle. The moving body 550 includes a motor 551, a non-aqueous power storage element 552, and wheels 553 as an example of a moving means.

The non-aqueous power storage element 552 supplies electric power to the motor 551 to drive the motor 551. The motor 551 that is driven by the non-aqueous power storage element 552 can cause the wheels 553 to drive, and as a result, the moving body 550 can move.

According to the above-described configuration, it is possible to prevent a short circuit between the positive electrode and the negative electrode, and additionally, the moving body is driven by electric power from a non-aqueous power storage element having excellent battery characteristics, so that it is possible to safely and efficiently move the moving body. The moving body 550 is not limited to the electric vehicle, but may be a PHEV, an HEV, or a locomotive and a motorcycle that can travel by using a combination of a diesel engine and an electrochemical element. Further, the moving body may be a transport robot used in a factory or the like, and may travel by using a non-aqueous power storage element or a combination of an engine and a non-aqueous power storage element. The moving body may be an object in which the object as a whole does not move, but only a part of the object moves, such as an assembly robot that is placed on a production line in a factory and can operate an arm or the like by using a non-aqueous power storage element or a combination of an engine and a nonaqueous power storage element.

[Examples]

[0150]

Examples of the present embodiment will be described below, but the scope of the present embodiment is not limited to the Examples. Note that the terms “parts” and “%” in the following Examples and Comparative Examples are “parts by mass” and “mass%,” unless otherwise specified.

[0151]

[Example 1]

(Preparation of Electrode) Preparation of Electrode Composite Layer>

60 parts of Lithium Nickelate 503H (manufactured by JFE Mineral Co., Ltd.) as a positive electrode active material, 36 parts of N-methylpyrrolidone as a dispersion medium, 2 parts of a resin as a binder (a resin for forming a positive electrode composite layer, trade name: PVDF 5130, manufactured by Solvay), and 2 parts of a conductive material (Ketjenblack 600JD, manufactured by Denka) were kneaded to obtain a slurry for forming a positive electrode composite layer.

By using a comma coater (trade name: COMMA REVERSE, manufactured by Hirano Tecseed Co., Ltd.), the slurry for forming a positive electrode composite layer was applied to both sides of an aluminum foil serving as a positive electrode base, and then dried.

Subsequently, a linear pressure of 100 kN/m was applied by using a roll press device (heating type 3 ton roll press RH-0307-2525H, manufactured by Thank-Metal Co., Ltd.) to prepare a positive electrode composite layer.

[0152]

Preparation of Negative Electrode Composite Layer>

60 parts of SCMG-XRs graphite (artificial graphite, manufactured by Showa Denko K.K.) as a negative electrode active material, 36 parts of water as a dispersion medium, 2 parts of a resin as a binder (acrylic resin, trade name: AZ-9129, manufactured by Zeon Corporation) and 2 parts of carboxymethyl cellulose ((H01496B) HS-6, manufactured by DKS Co. Ltd.) as a thickener were kneaded to obtain a slurry for forming a negative electrode composite layer. By using a comma coater (trade name: COMMA REVERSE, manufactured by Hirano Tecseed Co., Ltd.), the slurry for forming a negative electrode composite layer was applied to both sides of a copper foil serving as a negative electrode base, and then dried.

Subsequently, a linear pressure of 100 kN/m was applied by using a roll press device (heating type 3 ton roll press RH-0307-2525H, manufactured by Thank-Metal Co., Ltd.) to prepare a negative electrode composite layer.

[0153]

Preparation of Porous Layer>

30 parts by mass of EBECRYL4265 (trifunctional aliphatic urethane acrylate: manufactured by Daicel-Allnex Ltd.) as a polymerizable compound, 69.7 parts by mass of 2,6-dimethyl-4- heptanone (manufactured by Tokyo Chemical Industry Co., Ltd.) as a porogen, and 0.3 parts by mass of OMNIRAD 184 (manufactured by IGM Resins B.V.) as a photopolymerization initiator were filled into a container and sufficiently stirred. Subsequently, coarse particles were removed by using a 5 pm membrane filter to prepare a liquid composition for forming a porous layer.

By using a liquid discharge device EV2500 (manufactured by Ricoh Co., Ltd.) and a liquid discharge head MH5421F (manufactured by Ricoh Co., Ltd.), a liquid composition for forming a porous layer was applied onto the electrode composite layer (the positive electrode composite layer and the negative electrode composite layer). In a nitrogen atmosphere, the monomer was irradiated with ultraviolet rays to polymerize the monomer. Afterwards, the obtained product was heated on a hot plate at 120°C for 1 minute from the side opposite to the side where the liquid composition for forming a porous layer had been applied, to remove the porogen and form a porous layer. The average thickness of the porous layer was adjusted by adjusting the amount of the liquid composition for forming a porous layer discharged from the liquid discharge head.

[0154]

Preparation of Particle Layer>

A cooling nano-pulverizer (NP-100, manufactured by Thinky Corporation) including a container made of zirconia was used as a bead mill dispersion device. 40 parts of AKP-3000 (aluminum oxide, particle diameter: 0.7 pm, manufactured by Sumitomo Chemical Co., Ltd.) as particles, 58.4 parts of dipropylene glycol monomethyl ether (manufactured by Kanto Chemical Industry Co., Ltd.) as a dispersion medium, and 1.6 parts of MALIALIM (registered trademark) HKM-50A (manufactured by NOF Corporation) as a dispersant were filled into the container and zirconia beads having a particle diameter of 0.2 mm were appropriately added to disperse the mixture.

At this time, a cycle of dispersing the mixture was repeated three times. The cycle included a step of rotating the cooling nano-pulverizer under dispersion conditions including -20°C and 1500 rpm for 1 minute, and then, rotating the cooling nano-pulverizer at 400 rpm for 1 minute. After removing the zirconia beads, coarse particles were removed by using a 10 pm membrane filter to prepare a liquid composition for forming a particle layer.

A liquid composition for forming a particle layer was applied onto the porous layer by using a liquid discharge device EV2500 (manufactured by Ricoh Co., Ltd.) and a liquid discharge head MH5421F (manufactured by Ricoh Co., Ltd.). The dispersion medium was removed by heating on a hot plate at 120°C for 1 minute from the side opposite to the surface where the liquid composition for forming a particle layer had been applied, to form a particle layer. The average thickness of the particle layer was adjusted by adjusting the amount of the liquid composition for forming a particle layer discharged from the liquid discharge head. [0155] [Example 2] to [Example 14] and [Comparative Example 1] to [Comparative Example 2] An electrode was prepared by a method similar to the one in (Preparation of Electrode) in [Example 1] described above, except that the composition and contents were changed as illustrated in Tables 1 to 3 below.

[0156]

[Example 15]

In the above-described Preparation of Porous Layer>, the liquid composition for forming a porous layer was applied onto the electrode composite layer, and the polymerizable compound was polymerized by irradiation with ultraviolet rays in a nitrogen atmosphere. Subsequently, the porogen was not removed, and the liquid composition for forming a particle layer was applied onto the wet porous layer. The porogen was removed simultaneously with the removal step of the dispersion medium in Preparation of Particle Layer>. That is, the electrode was prepared by using a wet-on-wet lamination process.

[0157]

The components indicated in Tables 1 to 3 are described in detail below.

- Particles -

- AKP-3000 (high-purity alumina, particle diameter: 0.7 pm, manufactured by Sumitomo Chemical Co., Ltd.)

- AKP-20 (high-purity alumina, particle diameter: 0.4 pm, manufactured by Sumitomo Chemical Co., Ltd.)

- AKP-50 (high-purity alumina, particle diameter: 0.2 pm, manufactured by Sumitomo Chemical Co., Ltd.)

- AA-1.5 (Advanced Alumina, particle diameter: 1.7 pm, manufactured by Sumitomo Chemical Co., Ltd.)

- AKP-G07 (high-purity alumina, particle diameter: 0.03pm, manufactured by Sumitomo Chemical Co., Ltd.)

- Dispersant for Forming Particle Layer -

- MALIALIM (registered trademark) HKM-50A (high molecular polycarboxylic acid ammonium salt, manufactured by NOF Corporation)

- MALIALIM (registered trademark) SC-0708A (high molecular polycarboxylic acid, manufactured by NOF Corporation)

- MALIALIM (registered trademark) AKM-0531 (high molecular polycarboxylic acid, manufactured by NOF Corporation)

- DISPERBYK-118 (phosphoric acid polyester solution, manufactured by BYK GmbH) [0158]

[Method of Measuring Average Thickness of Porous Layer]

The electrode was cut to obtain a square piece of 5 mm that includes the electrode base, the electrode composite layer, and the insulator layer. The square piece was immersed into a degassed resin (two-component mixture, 30-minute curing epoxy resin, manufactured by Devcon), and cured at 40°C in an oven for 12 hours. After the square piece of the electrode was sufficiently cured, the square piece was cut in the thickness direction by using a razor, ion milling, a micro-microtome, or the like, to prepare a cross-sectional sample. The cross section of the obtained cross-sectional sample was finished by using a cross section polisher (SM-09010, manufactured by JEOL, Ltd.) under conditions including an acceleration voltage of 5.0 kV and a beam current of 120 pA. Next, a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) was used to randomly capture a plurality of images of the cross section including an upper end and a lower end of the porous layer under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times. The plurality of obtained images were imported into TIFF images, and image analysis software (IMAGE- PRO PLUS, manufactured by Media Cybernetics) was used to calculate the area of the porous layer in the cross section and the length of the porous layer in the width direction in the cross section, that is, the length in the horizontal direction with respect to the electrode base, from the scale bar and the number of pixels obtained by the image analysis. The film thickness was calculated by dividing the area by the length in the width direction.

Note that the “average thickness” was determined by calculating an average of measurement values obtained at 10 points, among the plurality of obtained images.

[0159]

[Method of Measuring Porosity]

A square piece of 5 mm was cut out from the electrode, an unsaturated fatty acid (commercially available butter) was filled into a container, and the electrode was subjected to osmium staining. A cross-sectional structure of an inner portion of the electrode was cut out by using an FIB, and the porosity in the resin was measured by using SEM. Further, the porosity difference was determined by trimming a region (A) and a region (B) in the obtained binarized image and calculating an area ratio of void portions in each of the region (A) and the region (B).

[0160]

[Method of Measuring Average Thickness of Particle Layer]

The electrode was cut to obtain a square piece of 5 mm that includes the electrode base, the electrode composite layer, and the insulator layer. The square piece was immersed into a degassed resin (two-component mixture, 30-minute curing epoxy resin, manufactured by Devcon), and cured at 40°C in an oven for 12 hours. After the square piece of the electrode was sufficiently cured, the square piece was cut in the thickness direction by using a razor, ion milling, a micro-microtome, or the like, to prepare a cross-sectional sample. The cross section of the obtained cross-sectional sample was finished by using a cross section polisher (SM-09010, manufactured by JEOL, Ltd.) under conditions including an acceleration voltage of 5.0 kV and a beam current of 120 pA. Next, a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) was used to randomly capture a plurality of images of the cross section including an upper end and a lower end of the particle layer under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times. The plurality of obtained images were imported into TIFF images, and image analysis software (IMAGE- PRO PLUS, manufactured by Media Cybernetics) was used to calculate the area of the particle layer in the cross section and the length of the particle layer in the width direction in the cross section, that is, the length in the horizontal direction with respect to the electrode base, from the scale bar and the number of pixels obtained by the image analysis. The film thickness was calculated by dividing the area by the length in the width direction.

[0161]

[Method of Measuring Volume Average Particle Diameter of Particles] The particle diameter was measured by using a particle size distribution analyzer (NANOTRAC WAVE-UT151, manufactured by MicrotracBEL Corp.). [0162]

Evaluation of Smoothness>

A surface roughness Ra of the negative electrodes obtained in Examples 1 to 15 and Comparative Examples 1 and 2 was measured by using a laser microscope (VK-X3000, magnification 50 times, manufactured by Keyence Corporation). The measured values were evaluated according to the following evaluation criteria. Note that an evaluation result of “C” or higher is within a range usable in practice.

- Evaluation Criteria of Smoothness -

A+: Less than 1 pm

A: 1 pm or more and less than 3 pm B: 3 pm or more and less than 5 pm C: 5 pm or more and less than 7 pm D: 7 pm or more [0163] Evaluation of Blocking Resistance> The positive electrodes and the negative electrodes obtained in Examples 1 to 15 and Comparative Examples 1 and 2 were each cut to obtain square pieces of 5 cm. The square pieces were stacked so that the particle layer in the positive electrode and the particle layer in the negative electrode were in contact. A piece of rubber having a square shape of 1.5 cm was placed in a center portion, and a weight (3 kg) was placed on top thereof. The square pieces were placed in a constant temperature bath at 120°C for 24 hours, and then, each of the particle layer of the positive electrode and the particle layer of the negative electrode was peeled off. The state of the surface of the particle layer was visually observed and evaluated according to the following evaluation criteria. Note that an evaluation result of “B” or higher is within a range usable in practice.

- Evaluation Criteria of Blocking Resistance -

A: Particle layers do not adhere to each other and surface of particle layers is not damaged B : Particle layers adhere slightly to each other, but surface of particle layers is not damaged C: Particle layers adhere to each other and surface of particle layers is damaged D: Particle layers strongly adhere to each other and cannot be peeled from each other [0164] Evaluation of Coverage Ratio of Particle Layer to Porous Layer>

The surface of the electrode including the porous layer and the particle layer was observed by using a scanning electron microscope (MERLIN, manufactured by Carl Zeiss Group) under conditions including an acceleration voltage of 2.0 kV and a magnification of 2500 times. Thus, a reflected electron image of the particle layer formed on the porous layer was obtained. Subsequently, the obtained image was imported into a TIFF image and binarized by using image analysis software (IMAGE-PRO PLUS, manufactured by Media Cybernetics) to calculate the coverage rate of the particle layer on the porous layer. At this time, the binarization conditions were appropriately set, so that the boundary between a porous layer region and a particle layer region was clearly observable. The samples were evaluated according to the following evaluation criteria. Note that an evaluation result of “B” or higher is within a range usable in practice.

- Evaluation Criteria of Coverage Rate - A+: 99% or higher

A: 90% or higher and less than 99% B: 60% or higher and less than 90% C: 40% or higher and less than 60% D: Less than 40% [0165]

< Eval nation of Abrasive Properties >

The abrasive properties of the electrodes obtained in Examples 1 to 15 and Comparative Examples 1 and 2 were measured in conformity with JIS K 7317. The device used in the measurement was HEIDON HHS2000S (manufactured by Shinto Scientific Co., Ltd.). An indenter was used in which a tip end portion made of a diamond having a spherical radius of 0.1 mm was attached to the test piece at an angle of 90°, and the indenter was moved at a speed of 1.0 mm/s while a load was applied to the indenter. Subsequently, the abrasive properties were evaluated from the maximum load that did not cause scratches. In the observation of scratches by an optical microscope, a portion where the surface of the electrode was exposed was determined to be a scratch. The samples were evaluated according to the following evaluation criteria. Note that an evaluation result of “B” or higher is within a range usable in practice.

- Evaluation Criteria of Abrasive Properties - A+: 40 gf or more

A: 30 gf or more and less than 40 gf B: 25 gf or more and less than 30 gf C: Less than 25 gf [0166] [Table 1]

[0167]

[Table 2]

[0168]

[Table 3]

[0169]

Aspects of the present disclosure include the following, for example.

According to a first aspect, an electrode includes a base, an electrode composite layer on the base, and an insulator layer on the electrode composite layer, wherein the insulator layer includes: a porous layer on the electrode composite layer and having a backbone and voids; and a particle layer on the porous layer and containing particles, a melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer, and a volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

According to a second aspect, in the electrode according to the first aspect, the porous layer has a two-phase continuous structure in which both the backbone and the voids are continuous.

According to a third aspect, in the electrode according to any one of the first aspect and the second aspect, the volume average particle diameter of the particles is 100 nm or more and 1,000 nm or less.

According to a fourth aspect, in the electrode according to any one of the first to third aspects, the average diameter of the voids is 10 nm or more and 200 nm or less. According to a fifth aspect, in the electrode according to any one of the first to fourth aspects, the porous layer has an average thickness of 5 pm or more and 20 pm or less, and the particle layer has an average thickness of 0.5 pm or more and 10 pm or less.

According to a sixth aspect, in the electrode according to any one of the first to fifth aspects, the backbone includes a cured product of a photocurable resin.

According to a seventh aspect, in the electrode according to the sixth aspect, the cured product has a cross-linked structure.

According to an eighth aspect, a non-aqueous power storage element includes the electrode according to any one of the first to seventh aspects.

According to a ninth aspect, a method of manufacturing an electrode includes: forming a particle layer containing particles, wherein the forming the particle layer includes applying a particle layer forming liquid composition onto a porous layer, the porous layer having a backbone and voids and disposed on an electrode composite layer on a base, a melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer, and a volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

According to a tenth aspect, the method according to the ninth aspect further includes: forming the porous layer on the electrode composite layer, wherein the forming the porous layer includes irradiating a porous layer forming liquid composition applied onto the electrode composite layer with light.

According to an eleventh aspect, in the method according to the tenth aspect, the forming the porous layer further includes heating the porous layer forming liquid composition to remove a porous layer forming solvent, and the heating the porous layer forming liquid composition is performed after the irradiating and before the forming the particle layer.

According to a twelfth aspect, in the method according to the tenth aspect, the forming the porous layer further includes heating the porous layer forming liquid composition to remove a porous layer forming solvent, and the heating the porous layer forming liquid composition is performed simultaneously with the forming the particle layer or after the forming the particle layer.

According to a thirteenth aspect, in the method according to the twelfth aspect, the forming the particle layer further includes heating the particle layer forming liquid composition to remove a particle layer forming solvent, and the heating the porous layer forming liquid composition and the heating the particle layer forming liquid composition are performed simultaneously.

[0170]

According to the electrode according to any one of the first to seventh aspects, the nonaqueous power storage element according to the eighth aspect, and the method of manufacturing an electrode according to any one of the ninth to thirteenth aspects, it is possible to solve the above-described conventional problems and achieve the object of the present embodiment.

[0171]

The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of the present invention. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.

[0172]

This patent application is based on and claims priority to Japanese Patent Application Nos. 2023-042475 and 2024-008461, filed on March 17, 2023 and January 24, 2024, in the Japan Patent Office, the entire disclosure of each of which is hereby incorporated by reference herein.

[Reference Signs List]

[0173]

1000 Negative electrode

1001 Negative electrode base

1002 Negative electrode composite layer

1003 Porous layer

1004 Particle layer

2000 Positive electrode

2001 Positive electrode base

2002 Positive electrode composite layer

2003 Porous layer

2004 Particle layer la Printing device lb Storage container 1c Supply tube

3 a Heating device

4 Base

5 Conveyor

7 Liquid composition for forming electrode composite layer

10 Printer

11 Base

12 Electrode composite layer

12A Liquid composition for forming electrode composite layer

30 Heater

101 Head

300 Discharge device 300' Liquid discharge device 300A' Liquid discharge device 300B' Liquid discharge device

304 Unwinding roller

305 Wind-up roller

306 Liquid discharge head 306 A Head

306B Head

307 Tank 307A Tank 307B Tank

308 Tube 3O8A Tube 3O8B Tube

309 Heating mechanism

310 Stage

3101 Pump 310A Pump 31 OB Pump

311 Valve 311A Valve 31 IB Valve

312 Valve

313 External tank

313 A External tank 313B External tank

314 Valve 400' Printer 400" Printer

4000 Transfer drum

4001 Intermediate transfer body

4002 Pre-processing unit

4003 Absorption unit

4004 Heating unit

4005 Cleaning unit

4006 Intermediate transfer belt

4007 Heating unit

4008 Cleaning roller 4009a Drive roller 4009b Counter roller 4009c Shape-maintaining roller

4009d Shape-maintaining roller

4009e Shape-maintaining roller

4009f Shape-maintaining roller

4009g Support roller

401 Head

420 Inkjet portion

422 Head module

550 Moving Body

551 Motor

552 Non-aqueous power storage element

553 Wheel

621 Impression cylinder

622 Transfer roller

Claims

[CLAIMS]

[Claim 1]

An electrode comprising: a base; an electrode composite layer on the base; and an insulator layer on the electrode composite layer, wherein the insulator layer includes: a porous layer on the electrode composite layer and having a backbone and voids; and a particle layer on the porous layer and containing particles, a melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer, and a volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

[Claim 2]

The electrode according to claim 1, wherein the porous layer has a two-phase continuous structure in which both the backbone and the voids are continuous.

[Claim 3]

The electrode according to claim 1 or 2, wherein the volume average particle diameter of the particles is 100 nm or more and 1,000 nm or less.

[Claim 4]

The electrode according to any one of claims 1 to 3, wherein the average diameter of the voids is 10 nm or more and 200 nm or less.

[Claim 5]

The electrode according to any one of claims 1 to 4, wherein the porous layer has an average thickness of 5 pm or more and 20 pm or less, and the particle layer has an average thickness of 0.5 pm or more and 10 pm or less.

[Claim 6]

The electrode according to any one of claims 1 to 5, wherein the backbone includes a cured product of a photocurable resin.

[Claim 7]

The electrode according to claim 6, wherein the cured product has a cross-linked structure.

[Claim 8]

A non-aqueous power storage element comprising the electrode according to any one of claims 1 to 7.

[Claim 9]

A method of manufacturing an electrode, the method comprising: forming a particle layer containing particles, wherein the forming the particle layer includes applying a particle layer forming liquid composition onto a porous layer, the porous layer having a backbone and voids and disposed on an electrode composite layer on a base, a melting point (Tma) or a glass transition temperature (Tga) of the particles is higher than a melting point (Tmb) or a glass transition temperature (Tgb) of the porous layer, and a volume average particle diameter (nm) of the particles is larger than an average diameter (nm) of the voids.

[Claim 10]

The method according to claim 9, further comprising: forming the porous layer on the electrode composite layer, wherein the forming the porous layer includes irradiating a porous layer forming liquid composition applied onto the electrode composite layer with light.

[Claim 11]

The method according to claim 10, wherein the forming the porous layer further includes heating the porous layer forming liquid composition to remove a porous layer forming solvent, and the heating the porous layer forming liquid composition is performed after the irradiating and before the forming the particle layer.

[Claim 12]

The method according to claim 10, wherein the forming the porous layer further includes heating the porous layer forming liquid composition to remove a porous layer forming solvent, and the heating the porous layer forming liquid composition is performed simultaneously with the forming the particle layer or after the forming the particle layer.

[Claim 13]

The method according to claim 12, wherein the forming the particle layer further includes heating the particle layer forming liquid composition to remove a particle layer forming solvent, and the heating the porous layer forming liquid composition and the heating the particle layer forming liquid composition are performed simultaneously.