Electrode elements, electrochemical elements, and energy storage devices

Abstract

To provide a separator-integrated electrode capable of preventing a short circuit with a counter electrode at the end of the electrode without deteriorating battery performance.SOLUTION: An electrode includes an electrode base, an electrode mixture material layer provided on the electrode base, and an insulating layer provided on one surface of the electrode mixture layer, and the insulating layer includes a first region including a first thick layer having a first thickness in a direction perpendicular to the one surface, and a second region including a second thick layer having a second thickness in a direction perpendicular to the first thick layer and the one surface, and the second region is at least a part of a peripheral edge of the one surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to electrodes, electrode elements, electrochemical elements, and energy storage devices. [Background technology]

[0002] In recent years, smartphones and laptop computers have become widespread in daily life, and electric vehicles, which do not have internal combustion engines, are beginning to attract attention worldwide as we aim for a decarbonized society. These electronic devices are equipped with lithium-ion secondary batteries (hereinafter sometimes referred to as lithium-ion batteries), which have the characteristics of high output and high energy density.

[0003] In lithium-ion batteries, a self-supporting separator made of polyolefin or the like is generally placed between the positive and negative electrodes to ensure insulation between them. However, self-supporting separators are known to be susceptible to stacking misalignment due to vibration or shock, and to contraction and short circuits during abnormal heat generation. To address these problems, a separator-integrated electrode with an insulating layer formed on the surface of either the negative or positive electrode has been proposed (see, for example, Patent Document 1). [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, with separator-integrated electrodes, when the electrodes are cut out using a slitter or mold, the insulating layer is not formed at the edges, resulting in exposed areas of the active material. This raises concerns that a short circuit may occur when the electrodes are in contact with each other during operation as an electrochemical element. The probability of a short circuit can be reduced by increasing the thickness of the insulating layer formed on the electrodes, but this presents challenges such as increased internal resistance and decreased volumetric energy density due to the increased distance between electrodes.

[0005] The object of the present invention is to provide a separator-integrated electrode that can prevent short circuits between the electrode end and the counter electrode without degrading battery performance. [Means for solving the problem]

[0006] One aspect of the present invention is an electrode comprising an electrode substrate, an electrode composite layer provided on the electrode substrate, and an insulating layer provided on one surface of the electrode composite layer, wherein the insulating layer has a first region including a first film thickness layer having a first thickness in a direction perpendicular to the one surface, and a second region including a second film thickness layer having a second thickness in a direction perpendicular to the first film thickness layer and the one surface, and the second region is at least a part of the peripheral edge of the one surface. [Effects of the Invention]

[0007] According to one aspect of the present invention, a separator-integrated electrode can be provided that prevents short circuits between the electrode end and the counter electrode without degrading battery performance. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram (part 1) showing an example of the plan view and cross-section of a first electrode on which a porous insulating layer having a first film thickness layer and a second film thickness layer of this embodiment is formed. [Figure 2] This is a schematic diagram (part 2) showing an example of the plan view and cross-section of a first electrode on which a porous insulating layer having a first film thickness layer and a second film thickness layer of this embodiment is formed. [Figure 3] This is a schematic diagram (part 3) showing an example of the plan view and cross-section of a first electrode on which a porous insulating layer having a first film thickness layer and a second film thickness layer of this embodiment is formed. [Figure 4] This is a schematic diagram (part 4) showing an example of the plan view and cross-section of a first electrode on which a porous insulating layer having a first film thickness layer and a second film thickness layer of this embodiment is formed. [Figure 5] This is a cross-sectional view of the second electrode of this embodiment. [Figure 6] This is a cross-sectional view (part 1) of the electrode laminate for the energy storage element of this embodiment. [Figure 7] This is a cross-sectional view (part 2) of the electrode laminate for the energy storage element of this embodiment. [Figure 8] Cross-sectional view (part 3) of the electrode laminate for the energy storage element of the present embodiment. [Figure 9] Schematic diagram (part 1) showing an example of a manufacturing apparatus for an electrode for an energy storage element. [Figure 10] Schematic diagram (part 2) showing an example of a manufacturing apparatus for an electrode for an energy storage element.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described. FIG. 1 is a schematic diagram (part 1) showing an example of a plan view and a cross-sectional view of a first electrode on which a porous insulating layer having a first film thickness layer and a second film thickness layer is formed.

[0010] <Electrode> The electrode according to the present embodiment includes an electrode substrate, an electrode binder layer, and an insulating layer. In this specification, an electrode is a general term for a negative electrode and a positive electrode. In the present embodiment, among the first electrode 5 constituting the positive electrode and the second electrode 11 constituting the negative electrode, which will be described later, the first electrode 5 is an example of the electrode of the present invention (FIGS. 1 and 5). Note that the first electrode 5 is not limited to the positive electrode and may be a negative electrode. When the first electrode 5 is a negative electrode, the second electrode 11 becomes the positive electrode.

[0011] <Electrode Substrate> The electrode substrate is also referred to as a current collector. The electrode substrate is a general term for a negative electrode substrate and a positive electrode substrate. In the present embodiment, among the current collector (positive electrode substrate) 8 of the first electrode 5 and the current collector (negative electrode substrate) 12 of the second electrode 11, which will be described later, the current collector (positive electrode substrate) of the first electrode 5 is an example of the electrode substrate in the electrode of the present invention (FIGS. 1 and 5).

[0012] The electrode substrate is not particularly limited as long as it is a conductive substrate. For example, aluminum foil, copper foil, stainless steel foil, titanium foil, an etched foil obtained by etching these to form fine holes, a perforated electrode substrate used in a lithium-ion capacitor, etc. are used. Such an electrode substrate can be suitably used for a secondary battery, a capacitor, etc., which are general power storage elements, and can be more suitably used for a lithium-ion secondary battery among them.

[0013] <Electrode composite material layer> The electrode composite material layer is provided on the electrode substrate. The electrode composite material layer is a general term for a positive electrode composite material layer and a negative electrode composite material layer. In the present embodiment, in the first electrode 5, an electrode composite material layer (positive electrode composite material layer) 9 is formed on an electrode substrate (positive electrode current collector) 8 (FIG. 1). The electrode composite material layer (positive electrode composite material layer) 9 is an example of the electrode composite material layer constituting the electrode of the present embodiment (FIGS. 1 and 5).

[0014] The form of the electrode composite material layer is not particularly limited and can be designed according to the purpose. The electrode composite material layer contains, for example, at least an active material (negative electrode active material or positive electrode active material), and may contain a binder (binding agent), a thickener, a conductive agent, etc. as necessary.

[0015] The electrode composite material layer is formed by dispersing a powdery active material, a binder, a conductive material, etc. in a liquid, and applying, fixing, and drying such a dispersion liquid on the electrode substrate. The coating method is not particularly limited, and for example, methods such as spraying, dispenser, die coater, dip coating, etc. can be used.

[0016] <Active material> The active material is a general term for a positive electrode active material and a negative electrode active material. The active material is not particularly limited as long as it is a material that can reversibly occlude and release alkali metal ions.

[0017] Typically, alkali metal-containing transition metal compounds can be used as the positive electrode active material. Examples of lithium-containing transition metal compounds include composite oxides containing lithium and at least one element selected from the group consisting of cobalt, manganese, nickel, chromium, iron, and vanadium.

[0018] Examples of composite oxides include lithium-containing transition metal oxides such as lithium cobaltate, lithium nickelate, and lithium manganate; olivine-type lithium salts such as LiFePO4; chalcogen compounds such as titanium disulfide and molybdenum disulfide; and manganese dioxide. Lithium-containing transition metal oxides are metal oxides containing lithium and a transition metal, or metal oxides in which a portion of the transition metal in the metal oxide is substituted with a different element.

[0019] Examples of heterogeneous elements include Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B, with Mn, Al, Co, Ni, and Mg being particularly preferred. These heterogeneous elements may be used individually or in combination of two or more. These positive electrode active materials can be used individually or in combination of two or more. When the electrode is used in a nickel-metal hydride battery, nickel hydroxide is an example of an active material.

[0020] Typically, carbon materials containing graphite having a graphite-type crystalline structure can be used as the negative electrode active material. Examples of such carbon materials include natural graphite, spherical or fibrous artificial graphite, hard carbon (difficult to graphitize), and soft carbon (easily graphitizable).

[0021] Examples of materials other than carbon materials include lithium titanate. Furthermore, from the viewpoint of increasing the energy density of lithium-ion batteries, high-capacity materials such as silicon, tin, silicon alloys, tin alloys, silicon oxide, silicon nitride, and tin oxide can also be suitably used as negative electrode active materials.

[0022] <Binding agent> Examples of binders that can be used include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamide-imide, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethylcellulose.

[0023] In addition, as a binder, copolymers of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene may also be used.

[0024] These binders may be used individually or in combination of two or more types.

[0025] <Conductive agent> Examples of conductive agents used in this embodiment include graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, Ketjen black, 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.

[0026] <Insulating layer> The insulating layer is provided on one surface of the electrode composite layer. In this embodiment, in the first electrode 5 (positive electrode), the insulating layer 10 is formed on one surface 91 of the electrode composite layer (positive electrode composite layer) 9 (Figure 1). In the second electrode 11 (negative electrode), the electrode composite layer (negative electrode composite layer) 13 is formed on both sides of the current collector (negative electrode base) 13, but no insulating layer is formed (Figure 5).

[0027] The insulating layer is not particularly limited, but its volume resistivity is 1 × 10⁻⁶. 12 It is preferable that the porous structure (hereinafter referred to as the porous insulating layer) exhibits a volume resistivity of 1 × 10⁻¹⁰. 12 Providing an insulating layer of (Ω·cm) or greater makes electrical short circuits between the positive and negative electrodes less likely to occur.

[0028] Regarding the shape of the porous insulating layer, from the viewpoint of ensuring good permeability of liquids and gases, it is preferable that the structure has a three-dimensional branched network structure as its framework, with multiple pores in the porous insulating layer being continuously connected. In other words, it is preferable that the porous insulating layer has many pores, and that each pore has communication with the surrounding pores and extends three-dimensionally. This communication between pores facilitates the penetration of liquids and gases.

[0029] One method for confirming that pores are interconnected is to observe a cross-section of a porous structure using a scanning electron microscope (SEM) to confirm that the connections between pores are continuous. One of the properties that can be obtained when pores are interconnected is air permeability.

[0030] The air permeability of the porous structure is measured, for example, in accordance with JIS P8117, and is preferably 1000 seconds / 100 mL or less, more preferably 500 seconds / 100 mL or less, and even more preferably 300 seconds / 100 mL or less.

[0031] In this case, the air permeability is measured using, for example, a Gurley-type densometer (manufactured by Toyo Seiki Seisakusho). Therefore, as an example, it may be determined that the pores are connected if the air permeability is 1000 seconds / 100 mL or less.

[0032] The cross-sectional shape of the void is not particularly limited and can be various shapes such as a roughly circular shape, a roughly elliptical shape, or a roughly polygonal shape. The size of the void is also not particularly limited. Here, the size of the void refers to the length of the longest straight line that can be drawn across the cross-sectional shape. The size of the void can be determined from cross-sectional images taken with a scanning electron microscope (SEM), etc.

[0033] The size of the pores in the porous structure is preferably between 0.1 μm and 10 μm, and more preferably between 0.1 μm and 1 μm. A pore size of 0.1 μm to 10 μm allows for sufficient penetration of liquids and gases within the porous structure, enabling efficient functioning of processes such as substance separation and reaction fields.

[0034] Furthermore, as will be described later, when a porous structure is used as an insulating layer for an energy storage element, if the size of the pores is 10 μm or less, it is possible to prevent short circuits between the positive and negative electrodes caused by lithium dendrites generated inside the energy storage element, thereby improving safety.

[0035] The porosity of the porous structure is preferably 30% or more, and more preferably 50% or more. Furthermore, the porosity of the porous structure is preferably 90% or less, and more preferably 85% or less.

[0036] A porosity of 30% or more allows for sufficient penetration of liquids and gases within the porous structure, enabling efficient functioning of processes such as substance separation and reaction fields. Furthermore, when a porous structure is used as an insulating layer in an energy storage element, the permeability of the electrolyte and ions is improved, allowing reactions within the element to proceed more efficiently. Additionally, a porosity of 90% or less improves the strength of the porous structure.

[0037] While there are no particular limitations on the method for measuring the porosity of a porous structure, one example is to fill the porous structure with unsaturated fatty acids (commercial butter), stain it with osmium, then cut out the internal cross-sectional structure using a FIB (Focused Ion Beam), and measure the porosity using a SEM (Scanning Electron Microscope).

[0038] The porous structure is not particularly limited, but is preferably an inorganic solid containing an inorganic oxide bound with a binder, or a resin structure with a resin backbone.

[0039] Examples of inorganic oxides constituting inorganic solids include mineral resource-derived materials such as aluminum oxide, titanium dioxide, barium titanate, zirconium dioxide, nickel oxide, manganese oxide, vanadium dioxide, silicon dioxide, and zeolites, or artificial products thereof. Among these, aluminum oxide and titanium dioxide are preferred from the viewpoint of electrical resistance and stability, aluminum oxide is more preferred, and α-alumina is even more preferred.

[0040] For example, the binder used to bind inorganic oxides is the binder described above.

[0041] In this embodiment, by including an inorganic oxide bound to the porous structure with a binder, it is possible to provide high insulation properties to the insulating layer composed of the porous structure while also achieving excellent adhesion to components other than the porous structure. Therefore, the insulation between the first electrode 5 and the opposing second electrode 11 can be improved while maintaining reliability.

[0042] Furthermore, the resin structure is a porous resin cured product having a skeletal structure formed of resin and pores in the areas where the skeletal structure is not formed. Preferably, the resin structure is a co-continuous structure or a monolithic structure, which is formed by the continuous arrangement of the resin portion and the pore portion.

[0043] In this embodiment, since the porous structure is a resin structure with a resin backbone, it is easier to form a porous insulating layer, and various functions can be imparted depending on the resin material and composition that constitute the porous structure, thereby improving the degree of design freedom.

[0044] In this embodiment, when a co-continuous resin structure is used as the porous insulating layer, the permeability of the electrolyte and ion permeability are improved in the energy storage element equipped with such a porous insulating layer, and the reaction inside the energy storage element proceeds efficiently.

[0045] The term "continuous resin portion" refers to a configuration in which there are no interfaces within the resin portion. In other words, it is distinct from a configuration where multiple resin particles are bound together by a binder or other material made of a different resin. Such a structure can be formed, for example, by the polymerization-induced phase separation method described later.

[0046] <1st area, 2nd area> The porous insulating layer (insulating layer) 10 of the electrode in this embodiment has a first region R1 and a second region R2.

[0047] The first region R1 does not include the second film thickness layer 10B, but includes the first film thickness layer 10A. The first region R1 represents the region having the first film thickness layer 10A on its surface in a plan view of the first electrode 5.

[0048] The first region R1 is the region of the porous insulating layer 10 formed on the first electrode 5 that mainly faces the electrode composite layer 13 of the second electrode 11. In other words, the first region R1 is the region included in the ion reaction field in the secondary battery, and the thinner the film thickness of the porous insulating layer 10 in the first region R1, the better the battery characteristics obtained (Figure 6).

[0049] The second region R2 includes the first film thickness layer 10A and the second film thickness layer 10B (Figure 1). The second region R2 represents the region of the first electrode 5 with the second film thickness layer 10B on its surface in a plan view. The second region R2 is the region of the porous insulating layer 10 formed on the first electrode 5, excluding the region facing the electrode composite layer 13 of the second electrode 11.

[0050] <First film thickness layer> The first film thickness layer 10A is part of the porous insulating layer 10 and is formed of the porous structure described above. By forming the first film thickness layer 10A of a porous structure, the electrolyte permeability and ion permeability of the first film thickness layer 10A, including the region R1 facing the second electrode 11, are improved.

[0051] The first film thickness layer 10A has a first thickness T11 in a direction perpendicular to one surface 91 of the electrode composite layer (positive electrode composite layer) 9 (Figure 6).

[0052] The thickness T11 of the first film layer 10A is not particularly limited, but is preferably 1.0 μm or more and 50.0 μm or less, and particularly preferably 5.0 μm or more and 20.0 μm or less.

[0053] By setting the thickness T11 of the first film layer 10A to 1.0 μm or more, a film thickness that is less prone to short circuits due to irregularities in the active material (electrode composite layer) can be secured, and good battery characteristics can be obtained by setting it to 50.0 μm or less. Furthermore, by setting the thickness T11 of the first film layer 10A to 5.0 μm or more, a film thickness that is even less prone to short circuits due to irregularities in the active material (electrode composite layer) can be secured, and even better battery characteristics can be obtained by setting it to 20.0 μm or less.

[0054] <Second film thickness layer> The second film thickness layer 10B is the portion of the porous insulating layer 10 excluding the first film thickness layer 10A, and may be formed of a non-porous structure, but it is preferable that it be formed of the porous structure described above. By forming the second film thickness layer 10B of a porous structure, the porous structure of the first film thickness layer 10A and the porous structure of the second film thickness layer 10B can be continuously integrated. This makes it possible to form the second film thickness layer 10B simultaneously with the first film thickness layer 10A.

[0055] Furthermore, the porous structure of the second film thickness layer 10B may be formed from a porous structure different from that of the first film thickness layer 10A. Here, a different porous structure refers to a porous structure in which the material constituting the porous structure, composition, and the degree of permeability, size of pores, cross-sectional shape of pores, etc., are relatively different.

[0056] Because the porous structure of the second film thickness layer 10B differs from that of the first film thickness layer 10A, different functions such as ion permeability and adhesion can be imparted to the first film thickness layer 10A and the second film thickness layer 10B of the porous insulating layer 10, respectively.

[0057] Furthermore, the porous structure of the first film thickness layer 10A may be different in the first region R1 and the second region R2. In this case, the porous structures of the first film thickness layer 10A and the second film thickness layer 10B in the second region R2 may be the same porous structure or different porous structures.

[0058] The second film thickness layer 10B has a second thickness T12 in a direction perpendicular to one surface 91 of the electrode composite layer (positive electrode composite layer) 9 (Figure 6). The insulating layer in the second region R2 is thicker than the insulating layer in the first region R1. Due to structural limitations during lamination, the thickness T12 of the second film thickness layer 10B is preferably less than or equal to half the thickness (total film thickness) T2 of the second electrode 11 (Figures 6 and 7).

[0059] The thickness of the insulating layer in the second region R2 (the sum of the thickness T11 of the first film layer 10A and the thickness T12 of the second film layer 10B) is not particularly limited, but it is preferable that the thickness is such that a short circuit does not occur when the second electrode 11 is pressed down on with the palm of a hand while the second electrode 11 is placed on top of the first electrode 5 (for example, 26 μm or more).

[0060] If the thickness of the second region R2 (the sum of the thickness T11 of the first film layer 10A and the thickness T12 of the second film layer 10B) exceeds half T21 of the total film thickness T2 of the second electrode 11, the distance between the first electrode and the second electrode will increase, which may cause a decrease in battery performance.

[0061] The second film thickness layer 10B may face the second electrode 11, but from the viewpoint of suppressing a decrease in battery performance, it is desirable that it not face the second electrode 11 as much as possible. Furthermore, if the area of ​​contact with the second electrode 11 is 20% or less compared to when the second film thickness layer 10B is not provided, the decrease in battery performance will be less likely to occur.

[0062] The material used for the second film thickness layer 10B is preferably an adhesive material. This allows the laminate to be integrated as shown in Figures 7 and 8, making it possible to manufacture a safer battery. Furthermore, the integration of the laminate improves its ability to retain the electrolyte (electrolyte discharge suppression effect), which is expected to improve battery life. Adhesive materials include resins that have a glass transition temperature.

[0063] In this embodiment, the porous insulating layer 10 is configured as a two-layer structure consisting of a first film thickness layer 10A and a second film thickness layer 10B, but it may also have a third film thickness layer (three-layer structure) or a multilayer structure with more layers.

[0064] In the electrode according to this embodiment, the second region R2 is at least a part of the peripheral edge 91A of one surface 91 of the electrode composite layer (positive electrode composite layer) 9. The peripheral edge 91A of one surface 91 of the electrode composite layer (positive electrode composite layer) 9 is a part of the electrode composite layer (positive electrode composite layer) 9 formed at the end of the first electrode 5.

[0065] Furthermore, the peripheral portion 91A is preferably 15% or less of the entire portion in the longitudinal or transverse direction of the electrode composite layer (positive electrode composite layer), with reference to the edge of the electrode composite layer (positive electrode composite layer), and preferably 1% or more.

[0066] Figures 1 to 4 show embodiments in which the second region R2 is at least a part of the peripheral edge 91A of one surface 91 of the electrode composite layer (positive electrode composite layer) 9. In all of Figures 1 to 4, one surface 91 of the electrode composite layer (positive electrode composite layer) 9 is rectangular. In Figures 2 to 3, parts common to Figure 1 are denoted by the same or corresponding reference numerals and their descriptions are omitted.

[0067] In the example in Figure 1, the second region R2 is formed continuously around the entire circumference of the peripheral edge 91A. In the example in Figure 2, the second region R2 is formed on three sides of one surface 91. In the example in Figure 3, the second region R2 is formed on two sides of one surface 91. Note that in the example in Figure 3, these two sides face each other on one surface 91. In the example in Figure 4, the second region R2 is formed discontinuously around the entire circumference of the peripheral edge 91A.

[0068] With this configuration, as shown in Figures 1-6, when multiple electrodes are stacked, the second electrode 11 is sandwiched between the first electrode 5, making it less likely for stacking misalignment to occur due to vibration or shock. Furthermore, even if stacking misalignment does occur, the thick porous insulating layer and the large distance between electrodes reduce the risk of short circuits, thus improving safety.

[0069] In the example shown in Figure 1, by continuously forming the second region R2 over the entire circumference of the peripheral portion 91A, the insulating layer 10 (second film thickness layer 10B) of the first electrode 5 can face the entire circumference of the peripheral edge of the second electrode 11. Therefore, the insulating properties can be improved while more stably positioning the second electrode 11 facing the first electrode 5.

[0070] Furthermore, in the examples shown in Figures 2 to 4, since it is formed only on a part of the peripheral portion 91A, the amount of material used for the insulating layer 10 can be reduced without compromising the stability of the arrangement of the second electrode 11 facing the first electrode 5 or reducing its insulating properties.

[0071] Furthermore, as shown in Figure 6, in this embodiment, a second electrode 11, which serves as a counter electrode, is sandwiched between two first electrodes 5 and laminated. In this configuration, the insulating layer 10 (second film thickness layer 10B) of the first electrode 5 reliably insulates the side edge of the electrode composite layer 9 of the first electrode 5 from the side edge of the electrode composite layer 13 of the second electrode 11, thereby preventing a short circuit between the first electrode 5 and the second electrode 11 (Figure 6).

[0072] Furthermore, as shown in Figure 7, in this embodiment, a second electrode 11, which acts as a counter electrode, is sandwiched between two first electrodes 5 and stacked, with the space between the two first electrodes 5 closed. In this configuration, the second electrode 11 can stably exist between the two first electrodes 5. This further reduces the likelihood of stacking misalignment due to vibration or shock (Figure 7).

[0073] Furthermore, as shown in Figure 8, in this embodiment, a second electrode 11, which serves as a counter electrode, is sandwiched between two first electrodes 5 and laminated, so that no gap is formed between the first electrodes 5 and the second electrodes 11. That is, in the example shown in Figure 8, the insulating layer 10 (second film thickness layer 10B) of the first electrode 5 and the side edge of the electrode composite layer 13 of the second electrode 11 are connected.

[0074] As a result, in the example shown in Figure 8, the configuration allows for the formation of an electrochemical element containing a larger electrode composite layer, thereby improving the energy density.

[0075] In the electrode of this embodiment, it is preferable that the second film thickness layer 10B is inclined such that its width W1 narrows as it moves away from the first region R1 in a direction perpendicular to one surface 91. Specifically, the porous structure in the second film thickness layer 10B changes continuously by half of the total film thickness T21 toward the first film thickness layer 10A. In other words, the second film thickness layer 10B is inclined such that its width W1 widens toward the first region R1 from above (Figures 1 to 4).

[0076] The tilt of the second film thickness layer 10B in this manner facilitates the stacking of the second electrode 11, which acts as a counter electrode to the first electrode 5 on which the insulating film is formed, and allows for stable stacking. As a result, it becomes easier to maintain a constant distance between the first electrode 5 and the second electrode 11, which is expected to improve the reliability of the battery (Figure 6).

[0077] The porous insulating layer material in this embodiment has a volume resistivity of 1 × 10⁻⁶ 12 As long as it has a thickness of (Ω·cm) or more, there are no particular restrictions, and examples include resins and inorganic solids. Furthermore, in the first film thickness layer 10A and the second film thickness layer 10B of the insulating layer in the first region R1 and the second region R2, it is possible to use different materials in combination, and it is also possible to use different materials in combination in the insulating layer of the first region and the insulating layer of the second region.

[0078] The resins that can be used for the porous insulating layer are not particularly limited, but examples include acrylate resins, methacrylate resins, urethane acrylate resins, vinyl ester resins, unsaturated polyester resins, epoxy resins, oxetane resins, vinyl ether resins, and resins that utilize the en-thiol reaction, which can be formed by irradiation with active energy rays such as ionizing radiation, ultraviolet rays, and infrared rays (heat).

[0079] Among these, acrylate resins, methacrylate resins, urethane acrylate resins, and vinyl ester resins that can form resins using highly reactive radical polymerization are preferred, and (meth)acrylic resins such as acrylate resins and methacrylate resins are more preferred.

[0080] Furthermore, it is preferable to use a resin that can be formed by irradiation with ionizing radiation and ultraviolet light. Since the resin can be formed instantaneously by irradiation with ionizing radiation and ultraviolet light, an improvement in productivity can be expected.

[0081] The liquid composition that forms a resin by polymerization preferably contains polymerizable compounds, solvents, polymerization initiators, and the like.

[0082] Furthermore, the liquid composition forms a porous structure upon curing. In this embodiment, the formation of a porous structure upon curing includes not only cases where a porous structure is formed within the liquid composition, but also cases where a porous structure precursor is formed within the liquid composition, and the porous structure is formed in a subsequent process (e.g., a heating process).

[0083] Furthermore, this term includes not only cases where the entire liquid composition hardens to form a porous structure, but also cases where some components of the liquid composition (such as polymerizable compounds) harden (polymerize) to form a porous structure, while other components of the liquid composition (such as solvents) do not harden and therefore do not form a porous structure.

[0084] Polymerizable compounds form resins upon polymerization, and when polymerized in a liquid composition, they form a porous structure. Furthermore, it is preferable that polymerizable compounds form resins upon irradiation with active energy rays. The resin formed from polymerizable compounds preferably has a cross-linked structure within the molecule, provided that a bifunctional or more polymerizable compound is used. This allows for an increase in the glass transition temperature or melting point of the porous structure, resulting in improved strength.

[0085] The active energy ray can be any ray capable of providing the energy necessary to advance the polymerization reaction of the polymerizable compound in the liquid composition, and is not particularly limited. Examples include ultraviolet rays, electron beams, alpha rays, beta rays, gamma rays, and X-rays. Among these, ultraviolet rays are preferred.

[0086] Furthermore, when using a particularly high-energy light source, the polymerization reaction can proceed without the use of a polymerization initiator. The polymerizable compound preferably has at least one radical polymerizable functional group. Examples include monofunctional, difunctional, or trifunctional or more radical polymerizable compounds, functional monomers, and radical polymerizable oligomers. Among these, difunctional or more radical polymerizable compounds are preferred.

[0087] Examples of monofunctional radical polymerizable compounds include 2-(2-ethoxyethoxy)ethyl acrylate, methoxypolyethylene glycol monoacrylate, methoxypolyethylene glycol monomethacrylate, phenoxypolyethylene glycol acrylate, 2-acryloyloxyethyl succinate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer. These may be used individually or in combination of two or more.

[0088] Examples of bifunctional radical polymerizable compounds include 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 tricyclodecanedimethanol diacrylate. These can be used individually or in combination of two or more.

[0089] Examples of radical polymerizable compounds with three or more functions include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH-modified glycerol triacrylate, EO-modified glycerol triacrylate, PO-modified glycerol triacrylate, and tri Examples include 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-tetrahydroxymethylcyclopentanone tetraacrylate. These can be used individually or in combination of two or more.

[0090] The content of polymerizable compounds in the resin-forming liquid composition is preferably 5.0% by mass or more and 70.0% by mass or less, more preferably 10.0% by mass or more and 50.0% by mass or less, and even more preferably 20.0% by mass or more and 40.0% by mass or less, based on the total amount of the liquid composition.

[0091] When the polymerizable compound content is 70.0% by mass or less, it is preferable because the size of the pores in the resulting porous structure does not become too small (less than a few nanometers), the porous structure has an appropriate porosity, and the tendency for liquid and gas penetration to be difficult to occur can be suppressed. Furthermore, when the polymerizable compound content is 5.0% by mass or more, it is preferable because a three-dimensional network structure of the resin is sufficiently formed, resulting in a sufficiently formed porous structure, and the strength of the resulting porous structure tends to improve.

[0092] Furthermore, when it is desired to obtain a resin with high hardness or abrasion resistance and a porous structure formed from this resin, the content of the polymerizable compound in the liquid composition is preferably 30.0% by mass or more and 70.0% by mass or less, more preferably 40.0% by mass or more and 70.0% by mass or less, and even more preferably 50.0% by mass or more and 70.0% by mass or less, relative to the total amount of the liquid composition. This is because increasing the content of the polymerizable compound relative to the total amount of the liquid composition makes it possible to achieve a resin with high hardness or abrasion resistance and a porous structure formed from this resin.

[0093] The solvent (hereinafter also referred to as "pologen") is a liquid that is miscible with polymerizable compounds. Furthermore, the solvent is a liquid that becomes miscible with the polymer (resin) during the polymerization process of the polymerizable compound in the liquid composition (phase separation occurs). The presence of a solvent in the liquid composition causes the polymerizable compound to form porous structures when polymerized within the liquid composition.

[0094] Furthermore, it is preferable that the solvent be able to dissolve compounds that generate radicals or acids upon exposure to light or heat (polymerization initiators described later). The solvent may be used alone or in combination of two or more. Note that the solvent is not polymerizable.

[0095] The boiling point of pologen when used alone, or when two or more types are used in combination, is preferably 50°C to 250°C at atmospheric pressure, and more preferably 70°C to 200°C. A boiling point of 50°C or higher suppresses the vaporization of pologen at room temperature, making it easier to handle the liquid composition and to control the pologen content in the liquid composition.

[0096] Furthermore, because the boiling point is below 250°C, the drying time for the polymerized pologen is shortened, improving the productivity of porous structures. In addition, the amount of pologen remaining inside the porous structure can be suppressed, improving the quality when the porous structure is used as a functional layer such as a separation layer for separating substances or a reaction layer as a reaction field.

[0097] Furthermore, the boiling point of pologen when used alone, or when two or more types are used in combination, is preferably 120°C or higher at normal pressure.

[0098] Examples of pologenes include ethylene glycols such as diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisopropyl ether, and dipropylene glycol monomethyl ether; esters such as γ-butyrolactone and propylene carbonate; and amides such as NN-dimethylacetamide. Liquids with relatively large molecular weights, such as methyl tetradecanoate, methyl decanoate, methyl myristate, and tetradecane, can also be used. Furthermore, liquids such as acetone, 2-ethylhexanol, and 1-bromonaphthalene can also be used.

[0099] It should be noted that not all liquids exemplified above are necessarily pologenes. As described above, a pologen is a liquid that is miscible with a polymerizable compound and, in the process of polymerization of the polymerizable compound within the liquid composition, becomes miscible with the polymer (resin) (undergoes phase separation). In other words, whether or not a liquid is a pologen depends on its relationship with the polymerizable compound and the polymer (the resin formed by the polymerization of the polymerizable compound).

[0100] Furthermore, as described above, the liquid composition only needs to contain at least one pologen that has the specific relationship described above with the polymerizable compound; therefore, it may also contain additional liquids that do not have the specific relationship described above with the polymerizable compound (liquids that are not pologens).

[0101] However, the content of liquids that do not have the above-mentioned specific relationship with polymerizable compounds (liquids that are not pologenes) is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably not included, based on the total amount of the liquid composition.

[0102] The pologen content in the liquid composition is preferably 30.0% by mass or more and 95.0% by mass or less, more preferably 50.0% by mass or more and 90.0% by mass or less, and even more preferably 60.0% by mass or more and 80.0% by mass or less, based on the total amount of the liquid composition.

[0103] When the porogen content is 30.0% by mass or more, it is preferable because the size of the pores in the resulting porous structure does not become too small (less than a few nanometers), the porous structure has an appropriate porosity, and the tendency for liquid and gas penetration to become difficult can be suppressed.

[0104] Furthermore, when the porogen content is 95.0% by mass or less, a sufficiently porous structure is obtained by sufficiently forming a three-dimensional network structure of the resin, and the strength of the resulting porous structure tends to improve, which is preferable.

[0105] Furthermore, when it is desired to obtain a resin having high hardness or abrasion resistance and a porous structure formed by this resin, the content of polymerizable compounds in the liquid composition is preferably 30.0% by mass or more and 70.0% by mass or less, more preferably 30.0% by mass or more and 60.0% by mass or less, and even more preferably 30.0% by mass or more and 50.0% by mass or less, based on the total amount of the liquid composition.

[0106] This is because increasing the content of polymerizable compounds relative to the total liquid composition and consequently decreasing the content of pologen relative to the total liquid composition makes it possible to realize a resin with high hardness or abrasion resistance and a porous structure formed by this resin. If the liquid composition consists of two types, liquid composition A and liquid composition B, it is sufficient that the pologen content in the liquid composition remains within the above range as the amount of liquid composition A and liquid composition B decreases.

[0107] As photoradical polymerization initiators, photoradical generators can be used. For example, photoradical polymerization initiators such as Michler ketone and benzophenone, known by trade names Irgacure and Darocure, and more specifically, benzophenone and acetophenone derivatives, such as α-hydroxy- or α-aminocetophenone, 4-aloyl-1,3-dioxolane, benzyl ketal, 2,2-diethoxyacetophenone, p-dimethylaminoacetophen, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, and pp'-dichlorobenzophenone. Phen, pp'-bis-diethylaminobenzophenone, Michler ketone, benzyl, benzoin, benzyldimethyl ketal, tetramethylthiuram monosulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, azobisisobutyronitrile, benzoin peroxide, di-tert-butyl peroxide, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-one, 1-(4-isopropylphenyl)-2-hydroxy -2-Methylpropan-1-one, methylbenzoylformate, benzoin isopropyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin ether, benzoin isobutyl ether, benzoin n-butyl ether, benzoin n-propyl, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1 ,2-diphenylethane-1-one, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl)titanium, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-1[4-(methylthio)phenyl]-2-molifolinopropan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocure 1173), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one monoacylphosphine oxide, bisacylphosphine oxide or titanocene, fluorescene, anthraquinone, thioxanthone or xanthone, rhofin dimer, trihalomethyl or dihalomethyl compounds, active ester compounds, organoboron compounds, etc. are preferably used.

[0108] Furthermore, photocrosslinking radical generators such as bisazide compounds may be included simultaneously. Also, when polymerization is carried out solely by heat, conventional radical generators such as azoisobutyronitrile (AIBN) or other thermal polymerization initiators can be used.

[0109] The polymerization initiator content is preferably 0.05% by mass or more and 10.0% by mass or less, and more preferably 0.5% by mass or more and 5.0% by mass or less, when the total mass of the polymerizable compound is 100.0% by mass, in order to obtain a sufficient curing rate.

[0110] From the viewpoint of workability when applying the liquid composition, the viscosity of the liquid composition at 25°C is preferably 1.0 mPa·s to 200.0 mPa·s, more preferably 1.0 mPa·s to 150.0 mPa·s, even more preferably 1.0 mPa·s to 30.0 mPa·s, and particularly preferably 1.0 mPa·s to 25.0 mPa·s.

[0111] By having a viscosity of 1.0 mPa·s to 200.0 mPa·s of the liquid composition, good ejection performance can be obtained even when the liquid composition is applied to an inkjet system. Here, viscosity can be measured using, for example, a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.).

[0112] Inorganic solid materials that can be used in porous insulating layers include ceramics such as alumina, silica, aluminum nitride, silicon nitride, cordierite, thyacron, mullite, stearite, yttria, zirconia, and silicon carbide, as well as inorganic solid electrolytes such as LLZ, LPS, LGPS, and allodyrodite. Among these, aluminum oxide and silica are preferred in terms of insulating properties and heat resistance, and α-alumina is more preferred.

[0113] The liquid composition that forms an inorganic solid layer when applied to the electrode composite layer preferably contains an inorganic solid, a dispersion medium, and a dispersant. From the viewpoint of forming a porous layer on the electrode composite layer, the inorganic solid is preferably in the form of particles.

[0114] Particles refer to solids with relatively small particle sizes. The dispersion medium refers to the medium in which the particles are dispersed. Particles have low solubility in the dispersion medium; for example, their solubility in the dispersion medium is less than 0.1% by mass.

[0115] The average particle size is preferably 50 nm to 1000 nm from the viewpoint of dispersion stability, more preferably 50 nm to 800 nm from the viewpoint of storage stability of the liquid composition, and even more preferably 100 nm to 600 nm from the viewpoint of improving the ejection characteristics when the liquid composition is ejected by inkjet to form a porous film.

[0116] Here, the average particle diameter is the average primary particle diameter (D50) at which the volume integration in the particle size distribution obtained by laser diffraction and scattering method reaches 50%.

[0117] The shape of the particles is not particularly limited and can include, for example, rectangular, spherical, elliptical, cylindrical, egg-shaped, dogbone-shaped, or amorphous.

[0118] The dispersion medium used in the liquid composition of this embodiment is either an aqueous or non-aqueous dispersion medium. The dispersion medium can be arbitrarily selected in relation to the particles used and the absorbent medium, such as the active material layer.

[0119] The aqueous dispersion medium is not particularly limited and includes, for example, water or a mixture of water and a highly polar solvent. Examples of highly polar solvents include methanol, ethanol, propanol, butanol, pentanol, hexanol, ethylene glycol, hexylene glycol, NMP, DMSO, DMF, acetone, and THF. The highly polar solvent may be used alone or as a mixture of two or more.

[0120] The non-aqueous dispersion medium is not particularly limited and includes, for example, styrene, toluene, xylene, methyl ethyl ketone, ethyl acetate, ethyl lactate, acetone, methanol, ethanol, n-propanol, isopropanol (IPA), n-butanol, isobutanol, tert-butanol, n-pentanol, n-hexanol, diacetone alcohol, N,N-dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), tetrahydrofuran (THF), hexylene glycol, and the like. The non-aqueous dispersion medium may be used alone or in combination of two or more.

[0121] The dispersant used in the liquid composition of this embodiment is a compound that adsorbs or binds to the surface of particles and has the function of suppressing aggregation of particles through electrostatic repulsion due to Coulomb force or steric hindrance due to molecular chains.

[0122] While there are no particular limitations on the dispersant, a dispersant containing a polymer resin (hereinafter sometimes referred to as a polymer dispersant) is preferably used from the viewpoint of improving the dispersibility of particles.

[0123] In this specification, a polymer means a polymer with a number-average molecular weight (Mn) of 1,000 to 1,000,000. Considering the viscosity of the liquid composition, the number-average molecular weight (Mn) of polymeric dispersants is preferably 1,000 to 10,000, and more preferably 1,000 to 5,000.

[0124] When polymeric dispersants are used in a non-aqueous dispersion medium, it is preferable that they contain a resin having acid anhydride groups in the main chain, as this allows them to be used with relatively low reactivity and without significantly affecting battery characteristics. Acid anhydride groups can function as adsorbent groups on the surface of particles. In addition to acid anhydride groups, other adsorbent groups of polymeric dispersants include, for example, carboxylic acid ester groups, amide groups, epoxy groups, and ether groups.

[0125] Among these, acid anhydride groups are preferred as adsorption groups for polymer-based dispersants, considering their adsorption properties to inorganic particles such as alumina particles, boehmite particles, apatite particles, titanium oxide particles, and silica particles.

[0126] The liquid composition of this embodiment can be manufactured using a dispersion device. Examples of dispersion devices include a stirrer, ball mill, bead mill, ring mill, high-pressure disperser, rotary high-speed shearing device, and ultrasonic disperser.

[0127] From the viewpoint of workability when applying the liquid composition, the viscosity of the liquid composition at 25°C is preferably 1.0 mPa·s to 200.0 mPa·s, more preferably 1.0 mPa·s to 150.0 mPa·s, even more preferably 1.0 mPa·s to 30.0 mPa·s, and particularly preferably 1.0 mPa·s to 25.0 mPa·s.

[0128] By having a viscosity of 1.0 mPa·s to 200.0 mPa·s of the liquid composition, good ejection performance can be obtained even when the liquid composition is applied to an inkjet system. Here, viscosity can be measured using, for example, a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.).

[0129] <Formation of a porous insulating layer> The porous insulating layer formation step is a step of forming an insulating layer consisting of an organic layer and / or an inorganic layer on the object to be applied, which is the first electrode. The porous insulating layer formation step (hereinafter referred to as the insulating layer formation step) includes a liquid application step of applying a liquid composition to the object to be applied, which is the first electrode, to form a liquid composition layer, and may optionally include a step of irradiating the liquid composition with active energy rays, or a removal step of removing the solvent contained in the liquid composition.

[0130] <Liquid application process> The liquid application step is a step of applying a liquid composition containing organic and / or inorganic compounds and a solvent or dispersion to the object to be applied, which is the first electrode. Preferably, the applied liquid composition forms a liquid composition layer, which is a liquid film of the liquid composition, on the object to be applied.

[0131] The method for applying the liquid composition is not particularly limited and includes various printing methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing. Among these, liquid ejection methods such as inkjet printing are preferred from the viewpoint that the position where the liquid composition is applied can be controlled.

[0132] <Irradiation process> The irradiation step is a process of irradiating the liquid composition applied in the liquid application step with active energy rays. In particular, in the case of a liquid composition that undergoes polymerization-induced phase separation, the first irradiation step improves the porosity of the porous resin that is ultimately produced, thereby improving the ability of the porous resin to incorporate fluids such as liquids or gases.

[0133] Specifically, by irradiating a liquid composition with active energy rays, a porous precursor having a porous structure that forms the basis for creating a highly porous resin is formed.

[0134] The active energy ray can be any ray capable of providing the necessary energy to advance the polymerization reaction of the polymerizable compound, and is not particularly limited. Examples include ultraviolet rays, electron beams, alpha rays, beta rays, gamma rays, and X-rays. Among these, ultraviolet rays are preferred. In particular, when using a high-energy light source, the polymerization reaction can proceed without the use of a polymerization initiator.

[0135] The following explanation focuses specifically on cases where the liquid composition undergoes polymerization-induced phase separation, and describes why the irradiation process forms a porous precursor.

[0136] As described above, when forming porous resins by polymerization-induced phase separation, the structure and properties of the porous resin change depending on the polymerization conditions. For example, when forming a porous resin under conditions where a liquid composition is irradiated with highly intensified active energy rays to promote the polymerization of polymerizable compounds, polymerization tends to proceed before sufficient phase separation occurs, making it difficult to produce a porous resin with a high porosity.

[0137] Therefore, in order to form a porous resin with a high porosity, the irradiation intensity of the activated energy rays is set so as not to be too high. Specifically, the irradiation intensity of the activated energy rays is set to 1 W / cm². 2 The following is preferable: 300 mW / cm² 2 Less than 100 mW / cm² is more preferable. 2 The following is even more preferable.

[0138] However, if the irradiation intensity of the active energy rays is too low, phase separation will proceed excessively, leading to variations and coarsening of the porous structure, and furthermore, the irradiation time will be longer, reducing productivity. For this reason, 10 mW / cm² is recommended. 2 Preferably, it is 30 mW / cm² or higher. 2 It is more preferable that the above conditions are met.

[0139] <Removal process> The removal step is a step of removing the solvent or dispersion from the liquid composition. The method for removing the solvent or dispersion is not particularly limited, and one example is a method of removing the solvent or dispersion from the porous resin by heating. In this case, heating under reduced pressure is preferable because it further promotes the removal of the solvent or dispersion and suppresses the residue of the solvent or dispersion in the insulating layer that is formed.

[0140] <Insulating layer manufacturing equipment> The above-described insulating layer formation process can be realized by the insulating layer manufacturing apparatus shown in Figure 9. The insulating layer manufacturing apparatus 600 shown in Figure 9 includes a printing process section 100 which includes a step of applying a liquid composition onto a printing substrate 5 to form a liquid composition layer, and a heating process section 300 which includes a heating step of heating the printing substrate 5 on which the liquid composition layer has been formed to obtain a porous insulating layer.

[0141] The insulating layer manufacturing apparatus 600 includes a transport unit 7 for transporting the printing substrate 5, and the transport unit 7 transports the printing substrate 5 to the printing process unit 100 and the heating process unit 300 in that order at a preset speed.

[0142] The printing process unit 100 includes a printing apparatus 1A, which is an example of an application means for realizing an application process of applying a liquid composition onto a printing substrate 5; a storage container 1B for containing the liquid composition; and a supply tube 1C for supplying the liquid composition stored in the storage container 1B to the printing apparatus 1A.

[0143] The printing apparatus 1A is not particularly limited as long as it can apply the liquid composition 6. For example, any printing apparatus can be used that is suitable for various printing methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing.

[0144] The containment container 1B contains the liquid composition 6, and the printing process unit 100 dispenses the liquid composition 6 from the printing device 1A and applies the liquid composition 6 onto the printing substrate 5 to form a thin film layer of the liquid composition.

[0145] The containment container 1B may be integrated with the insulating layer manufacturing apparatus 600, or it may be detachable from the insulating layer manufacturing apparatus 600. It may also be a container used for adding to the containment container integrated with the insulating layer manufacturing apparatus 600 or to the containment container detachable from the insulating layer manufacturing apparatus 600.

[0146] The containment container 1B and the supply tube 1C can be arbitrarily selected as long as they can stably store and supply the liquid composition 6. The materials constituting the containment container 1B and the supply tube 1C preferably have light-shielding properties in the relatively short wavelength regions of ultraviolet and visible light. This prevents the liquid composition 6 from undergoing polymerization due to ambient light.

[0147] In the printing process section 100, the method for adjusting the thickness of the liquid composition layer formed on the printing substrate 5 is not particularly limited. Examples of methods for adjusting the thickness of the liquid composition layer include changing the ink deposition density or changing the ink discharge amount.

[0148] As shown in Figure 1, the heating process section 300 has a heating device 3A and includes a solvent removal step in which the solvent remaining in the liquid composition layer formed by the printing process section 100 is heated and dried by the heating device 3A to remove it. This makes it possible to form a porous resin. The heating process section 300 may perform the solvent removal step under reduced pressure.

[0149] Furthermore, the heating process section 300 includes a heating printing completion step in which the porous material is heated under reduced pressure after the solvent removal step. The heating device 3A is not particularly limited as long as it satisfies the above functions, and examples include IR heaters and hot air heaters.

[0150] Furthermore, the heating temperature and time can be appropriately selected depending on the boiling point of the solvent contained in the liquid composition layer and the film thickness to be formed.

[0151] Any material can be used as the printing substrate 5, regardless of whether it is transparent or opaque. Specifically, transparent substrates can include glass substrates, resin film substrates such as various plastic films, and composite substrates thereof, while opaque substrates can include silicon substrates, metal substrates such as stainless steel, or laminates of these materials.

[0152] The printing substrate 5 may be a recording medium such as plain paper, glossy paper, specialty paper, or cloth. Furthermore, the recording medium may be a low-permeability substrate (low-absorbency substrate).

[0153] Low-permeability substrates refer to substrates with a surface that has low water permeability, absorption, or adsorption, and include materials that have numerous internal cavities but do not open to the outside. Examples of low-permeability substrates include coated paper used in commercial printing and recording media such as cardboard with recycled paper pulp incorporated into the middle and back layers and coated on the surface.

[0154] The printing substrate 5 may also be a porous resin sheet used as an insulating layer for energy storage elements or power generation elements.

[0155] Furthermore, the shape of the printing substrate 5 is not particularly limited; for example, any substrate that is applicable to the printing process section 100 can be used, whether it is a curved surface or has an uneven shape.

[0156] Furthermore, in the insulating layer manufacturing apparatus 600, after the process from the printing process section 100 to the heating process section 300 is completed, the process from the printing process section 100 to the heating process section 300 may be repeated one or more times. Alternatively, after the printing process section 100, the printing process section 100 may be repeated one or more times before proceeding to the heating process section 300.

[0157] Furthermore, in the insulating layer manufacturing apparatus 600, the first film thickness layer 10A and the second film thickness layer 10B of the insulating layer 10 may be formed simultaneously in a single printing process section 100. Alternatively, the process may be divided into two printing processes 100, with the first film thickness layer 10A being formed in the first printing process section 100 and the second film thickness layer 10B being formed in the second printing process section 100.

[0158] Furthermore, the insulating layer formation process described above can also be realized by the insulating layer manufacturing apparatus shown in Figure 10. In Figure 10, parts common to Figure 9 are denoted by the same or corresponding reference numerals and their descriptions are omitted. The insulating layer manufacturing apparatus 600 shown in Figure 10 further includes a polymerization process section 200 between the printing process section 100 and the heating process section 300, which includes a polymerization process to obtain a porous resin precursor by activating the polymerization initiator of the liquid composition layer and polymerizing a polymerizable compound.

[0159] As shown in Figure 10, the polymerization process section 200 includes a light irradiation device 2A, which is an example of a curing means for realizing a curing process in which a liquid composition is cured by irradiation with active energy rays such as heat and light, and a polymerization inert gas circulation device 2B for circulating polymerization inert gas. The light irradiation device 2A irradiates the liquid composition layer formed by the printing process section 100 with light in the presence of polymerization inert gas to photopolymerize and obtain a porous resin precursor.

[0160] The light irradiation device 2A is appropriately selected according to the absorption wavelength of the photopolymerization initiator contained in the liquid composition layer and is not particularly limited as long as it can initiate and promote the polymerization of the compound in the liquid composition layer. Examples include ultraviolet light sources such as high-pressure mercury lamps, metal halide lamps, hot cathode tubes, cold cathode tubes, and LEDs. However, since shorter wavelength light generally tends to penetrate deeper, it is preferable to select a light source according to the thickness of the porous film to be formed.

[0161] Next, regarding the irradiation intensity of the light source of the light irradiation device 2A, if the irradiation intensity is too strong, polymerization proceeds rapidly before sufficient phase separation occurs, and thus it tends to be difficult to obtain a porous structure. Also, if the irradiation intensity is too weak, phase separation proceeds on a microscale or larger, and porosity variation and coarsening are likely to occur. Further, the irradiation time also becomes long, and productivity tends to decrease. Therefore, the irradiation intensity is preferably 10 mW / cm 2 or more and 1 W / cm 2 or less, more preferably 30 mW / cm 2 or more and 300 mW / cm 2 or less.

[0162] Next, the polymerization inert gas circulation device 2B plays a role of reducing the concentration of polymerization-active oxygen contained in the atmosphere and allowing the polymerization reaction of the polymerizable compound near the surface of the liquid composition layer to proceed without being inhibited. Therefore, the polymerization inert gas used is not particularly limited as long as it satisfies the above function, and examples thereof include nitrogen, carbon dioxide, argon, and the like.

[0163] Also, considering that the inhibition reduction effect can be effectively obtained as its flow rate, it is preferable that the O2 concentration is less than 20% (an environment with a lower oxygen concentration than the atmosphere), more preferably 0% or more and 15% or less, and still more preferably 0% or more and 5% or less. Further, in order to realize stable polymerization progress conditions, it is preferable that the polymerization inert gas circulation device 2B is provided with temperature control means capable of adjusting the temperature.

[0164] In the heating engineering part 300, in the solvent removal process, the solvent remaining in the porous resin precursor formed by the polymerization engineering part 200 is heated and dried by the heating device 3A and removed. Thereby, a porous resin can be formed.

[0165] Furthermore, the heating section 300 also includes a polymerization acceleration step, in which the porous membrane precursor is heated by the heating device 3A to further accelerate the polymerization reaction carried out in the polymerization section 20, and an initiator removal step, in which the photopolymerization initiator remaining in the porous membrane precursor is removed by heating and drying it with the heating device 3A. Note that these polymerization acceleration step and initiator removal step may be performed before or after the solvent removal step, rather than simultaneously with the solvent removal step.

[0166] Furthermore, the heating process section 300 includes a polymerization completion step in which the porous material is heated under reduced pressure after the solvent removal step. The heating device 3A is not particularly limited as long as it satisfies the above functions, and examples include IR heaters and hot air heaters.

[0167] Furthermore, in the insulating layer manufacturing apparatus 600 including the polymerization process section 200, after the process from the printing process section 100 to the heating process section 300 is completed, the process from the printing process section 100 to the heating process section 300 may be repeated one or more times. Alternatively, after the printing process section 100, the process from the printing process section 100 to the polymerization process section 200 may be repeated one or more times before proceeding to the heating process section 300.

[0168] Furthermore, in the insulating layer manufacturing apparatus 600, the formation of the first film thickness layer 10A and the second film thickness layer 10B of the insulating layer 10 may be carried out in a single process from the printing process section 100 to the polymerization process section 200, with the first film thickness layer 10A and the second film thickness layer 10B being formed simultaneously.

[0169] Alternatively, the process from the printing process section 100 to the polymerization process section 200 may be performed at least twice, with the first film thickness layer 10A being formed in the first printing process section 100 to the polymerization process section 200, and the second film thickness layer 10B being formed in the second printing process section 100 to the polymerization process section 200.

[0170] <Electrode element> The electrode element according to this embodiment is an electrode element in which a positive electrode and a negative electrode are stacked in a state where they are insulated from each other. At least one of the positive electrode or negative electrode constituting the electrode element is made of an electrode on which the above-mentioned insulating layer is formed. In this embodiment, as an example of an electrode element, an electrode stack for an energy storage element is configured having two first electrodes 5 and a second electrode 11 (Figures 6 to 8).

[0171] In this electrode laminate for energy storage element, the first electrode 5 constitutes the positive electrode, the second electrode 11 constitutes the negative electrode, and the second electrode 11, which acts as the opposing electrode, is sandwiched between the two first electrodes 5 in a laminated structure. As a result, an insulating layer 10 (first film thickness layer 10A, second film thickness layer 10B) formed on the first electrode 5 is positioned between the first electrode 5 and the second electrode 11 (Figures 6 to 8).

[0172] In the electrode element of this embodiment, since the first electrode 5 having the insulating layer 10 described above is used, the same effects as the first electrode 5 can be obtained.

[0173] In other words, in the electrode element of this embodiment, as shown in Figures 1 to 6, when multiple electrodes are stacked, the second electrode 11 is sandwiched between the first electrode 5, making it less likely for stacking misalignment to occur due to vibration or shock. Furthermore, even if stacking misalignment does occur, the thickness of the porous insulating layer and the distance between electrodes are large, so the risk of short circuits is reduced, and an improvement in safety can be expected.

[0174] Although the configuration described here involves only the first electrode 5 having an insulating layer, the electrodes according to this embodiment may also be configured such that both the first electrode 5 and the second electrode 11, which is the counter electrode to the first electrode, each have an insulating layer.

[0175] <Electrochemical elements> The electrochemical element according to this embodiment has an electrode on which the above-described insulating layer is formed. In this embodiment, as an example of an electrochemical element, the above-described electrode element is provided in a lithium-ion secondary battery, which is a type of energy storage device.

[0176] Lithium-ion secondary batteries (hereinafter sometimes referred to as lithium-ion batteries) are a type of electrochemical device and are classified as non-aqueous electrolyte batteries, using an electrolyte solution in which an ionic conductive lithium salt is dissolved in an electrolyte solution such as a non-aqueous solvent.

[0177] The lithium-ion secondary battery of this embodiment includes a step of manufacturing electrodes using the electrode manufacturing method described above.

[0178] The configuration of the lithium-ion secondary battery in this embodiment is not particularly limited as long as it has the electrodes described above. The lithium-ion secondary battery includes, for example, an electrode element, an electrolyte layer formed on the electrode element, an outer casing that houses the electrode element and the electrolyte layer and seals the inside, and lead wires connected to the electrode element and extended to the outside of the outer casing.

[0179] The electrode element consists of a negative electrode and a positive electrode stacked with a separator in between. Here, the positive electrode is stacked on both sides of the negative electrode. Furthermore, a negative electrode lead wire is connected to the negative electrode substrate, and a positive electrode lead wire is connected to the positive electrode substrate.

[0180] The negative electrode has a negative electrode active material layer and a porous insulating layer sequentially formed on both sides of the negative electrode substrate.

[0181] The positive electrode has positive electrode active material layers formed on both sides of the positive electrode substrate. Alternatively, the positive electrode active material layer and a porous insulating layer may be formed sequentially on both sides of the positive electrode substrate. In this case, the porous insulating layer may be omitted if necessary.

[0182] There are no particular restrictions on the number of stacked negative and positive electrodes in the electrode element. Also, the number of negative electrodes and positive electrodes in the electrode element may be the same or different.

[0183] Lithium-ion batteries may have other components as needed.

[0184] There are no particular restrictions on the shape of lithium-ion batteries. Examples include laminated types, cylinder types with spiral-shaped sheet electrodes and separators, cylinder types with an inside-out structure combining pellet electrodes and separators, and coin types with stacked pellet electrodes and separators.

[0185] The electrolyte layer is composed of a non-aqueous electrolyte. A non-aqueous electrolyte is an electrolyte in which the electrolyte salt is dissolved in a non-aqueous solvent. As the non-aqueous electrolyte, a solid electrolyte or a non-aqueous electrolyte can be used.

[0186] There are no particular restrictions on the non-aqueous solvent, but it is preferable to use, for example, an aprotic organic solvent. As the aprotic organic solvent, carbonate-based organic solvents such as linear carbonates and cyclic carbonates can be used. Among these, linear carbonates are preferred because they have high solubility for electrolyte salts. Furthermore, it is preferable that the aprotic organic solvent has low viscosity.

[0187] Examples of linear carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC).

[0188] The content of linear carbonates in the non-aqueous solvent is preferably 50% by mass or more. When the content of linear carbonates in the non-aqueous solvent is 50% by mass or more, even if the non-aqueous solvent other than the linear carbonates is a cyclic substance with a high dielectric constant (e.g., cyclic carbonate, cyclic ester), the content of the cyclic substance will be low. Therefore, even when a high-concentration non-aqueous electrolyte of 2M or more is prepared, the viscosity of the non-aqueous electrolyte will be low, resulting in good penetration of the non-aqueous electrolyte into the electrode and good ion diffusion.

[0189] Examples of cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC).

[0190] In addition to carbonate-based organic solvents, other non-aqueous solvents that can be used include, for example, ester-based organic solvents such as cyclic esters and linear esters, and ether-based organic solvents such as cyclic ethers and linear ethers.

[0191] Examples of cyclic esters include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.

[0192] Examples of linear esters include alkyl propionates, dialkyl malonates, alkyl acetates (e.g., methyl acetate (MA), ethyl acetate), and alkyl formate (e.g., methyl formate (MF), ethyl formate).

[0193] Examples of cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, and 1,4-dioxolane.

[0194] Examples of linear ethers include 1,2-dimethylethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

[0195] The electrolyte salt is not particularly limited as long as it has high ionic conductivity and can be dissolved in a non-aqueous solvent. Preferably, the electrolyte salt contains a halogen atom.

[0196] Examples of cations constituting the electrolyte salt include lithium ions. That is, lithium salts can be used as the electrolyte salt. There are no particular restrictions on the lithium salt used; it can be appropriately selected depending on the purpose.

[0197] Examples of lithium salts include lithium hexafluorophosphate (LiPF6), lithium borofluoride (LiBF4), lithium arsenide hexafluoride (LiAsF6), lithium trifluoromethasulfonate (LiCF3SO3), lithium bis(trifluoromethylsulfonyl)imide (LiN(CF3SO2)2), and lithium bis(pentafluoroethylsulfonyl)imide (LiN(C2F5SO2)2). Among these, LiPF6 is preferred in terms of ionic conductivity, and LiBF4 is preferred in terms of stability.

[0198] Examples of anions that make up the electrolyte salt include BF4. - PF6 - AsF6 - CF3SO3 - (CF3SO2)2N - (C2F5SO2)2N - These are some examples. Note that electrolyte salts may be used individually or in combination of two or more types.

[0199] The concentration of the electrolyte salt in the non-aqueous electrolyte can be appropriately selected depending on the purpose. For swing-type lithium-ion batteries, a concentration of 1 mol / L to 2 mol / L is preferred, while for reserve-type lithium-ion batteries, a concentration of 2 mol / L to 4 mol / L is preferred.

[0200] There are no particular restrictions on the applications of lithium-ion rechargeable batteries. Examples include laptop computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, headphone stereos, video cameras, LCD TVs, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, lighting fixtures, toys, game consoles, clocks, strobes, and cameras.

[0201] In this embodiment, since the above-described electrode element (an electrode element comprising a first electrode 5 having the above-described insulating layer 10) is used, the same effects as those of the first electrode 5 can be obtained.

[0202] In other words, in the electrochemical element (energy storage device) of this embodiment, as shown in Figures 1 to 6, when multiple electrodes are stacked, the second electrode 11 is sandwiched between the first electrode 5, making it less likely for stacking misalignment to occur due to vibration or shock. Furthermore, even if stacking misalignment does occur, the thickness of the porous insulating layer and the distance between electrodes are large, so the risk of short circuits is reduced, and an improvement in safety can be expected. [Examples]

[0203] <Preparation of resin-forming liquid composition> The materials were mixed in the following proportions to prepare a resin-forming liquid composition.

[0204] -Resin forming liquid composition (resin 1)- A liquid composition for resin 1 was obtained by mixing 29.0% by mass of tricyclodecanedimethanol diacrylate (manufactured by Daicel Ornex Co., Ltd.) as a polymerizable compound, 70.0% by mass of dipropylene glycol monomethyl ether (manufactured by Kanto Chemical Industry Co., Ltd.) as a pologen, and 1.0% by mass of a polymerization initiator (manufactured by BASF, Irgacure® 184).

[0205] -Resin 2- A polymerizable compound (EBECRYL8® 402, manufactured by Daicel Ornex Co., Ltd.) was mixed at a ratio of 39.0% by mass, diisobutyl ketone (manufactured by Kanto Chemical Industry Co., Ltd.) as a pologen at a ratio of 60.0% by mass, and a polymerization initiator (Irgacure® 819, manufactured by BASF) at a ratio of 1.0% by mass to obtain a liquid composition for resin 2.

[0206] <Preparation of an inorganic solid-forming liquid composition> An inorganic solid-forming liquid composition was prepared by dispersing a pre-dispersion of materials mixed in the proportions shown below, according to the following procedure.

[0207] -Inorganic solid forming liquid composition- A pre-dispersion was prepared by mixing 40.0% by mass of α-alumina (primary particle size (D50) of 0.5 μm and specific surface area of ​​7.8 g / m2) as an inorganic solid, 58.0% by mass of a mixed solution of dimethyl sulfoxide and ethylene glycol (DMSO-EG), and 2.0% by mass of a dispersant (Marialim® HKM-150A, manufactured by NOF Corporation).

[0208] This pre-dispersion was placed in a container together with zirconia beads (Φ2 mm) and dispersed using a cryogenic nano-pulverizer NP-100 (manufactured by Thinky Co., Ltd.) at 1500 rpm for 3 minutes to obtain a dispersion. The zirconia beads were removed from the obtained dispersion using a 25 μm mesh filter to prepare a liquid composition.

[0209] <Fabrication of the negative electrode> To form the negative electrode composite layer, a negative electrode coating was prepared by adding 97.0% by mass of graphite, 1.0% by mass of a thickener (carboxymethylcellulose), 2.0% by mass of a polymer (styrene-butadiene rubber), and 100.0% by mass of water as a solvent.

[0210] This negative electrode coating was applied to both sides of a copper foil substrate and dried to obtain a negative electrode with a basis weight of 9.0 mg / cm² on each side of the negative electrode composite layer. Next, the electrode was pressed using a roll press machine to achieve a deposition density of 1.6 g / cm³ to obtain the negative electrode for use. The total film thickness of the negative electrode at this time was 112.0 μm.

[0211] <Fabrication of the positive electrode> A cathode coating was prepared by dispersing 92.0% by mass of lithium nickelate (NCA) as the cathode active material, 3.0% by mass of acetylene black as the conductive material, and 5.0% by mass of polyvinylidene fluoride (PVDF) as the binder in N-methylpyrrolidone (NMP).

[0212] This positive electrode coating was applied to both sides of an aluminum foil substrate and then dried to obtain a positive electrode with a basis weight of 15.0 mg / cm² on each side of the positive electrode composite layer. Next, the electrode was pressed using a roll press machine to obtain a positive electrode with a volume density of 2.8 g / cm³. The total film thickness of the positive electrode at this time was 132.0 μm.

[0213] <Formation of a porous insulating layer> [Example 1] The liquid composition for resin 1 was filled into an inkjet ejector equipped with an inkjet head (GEN5 head, manufactured by Ricoh Printing Systems Co., Ltd.). The amount of liquid composition ejected to the negative electrode was controlled to form a coated area in the pattern image shown in Figure 1, such that the insulating layer of the first region and the insulating layer of the second region had the configuration described below. Insulating layer of region 1: Area: 47.0 mm × 27.0 mm, Film thickness: 20.0 μm Insulating layer of region 2: Area: Excluding the insulating layer of region 1; Film thickness: 26.0 μm

[0214] Subsequently, the coated area was immediately cured under an N2 atmosphere by UV irradiation (light source: UV-LED (Phoseon, FJ800), wavelength: 365 nm, irradiation intensity: 30 mW / cm2, irradiation time: 20 s). Next, the cured material was heated at 120°C for 1 minute using a hot plate to remove porogenes and obtain a porous insulating layer.

[0215] [Examples 2-5] In Example 1, the porous insulating layer of Examples 2 to 5 was formed in the same manner as in Example 1, except that the thickness of the insulating layer in the second region was changed to the thickness shown in Table 1.

[0216] [Example 6] A liquid composition for resin 1 was filled into an inkjet ejector equipped with a GEN5 head, and the liquid composition was ejected onto the negative electrode substrate to form a solid image-like coated area with a film thickness of 20.0 μm. Immediately thereafter, the coated area was cured under an N2 atmosphere by UV irradiation (light source: UV-LED (Phoseon, product name: FJ800), wavelength: 365 nm, irradiation intensity: 30 mW / cm2, irradiation time: 20 s). Next, pologenes were removed by heating the cured material at 120°C for 1 minute using a hot plate.

[0217] Next, the liquid composition for resin 2 was filled into an inkjet ejector equipped with a GEN5 head, and the liquid composition was ejected to the area excluding the 47.0 mm × 27.0 mm negative electrode area where resin 1 was formed to a thickness of 20.0 μm, forming a coated area in the pattern image shown in Figure 1, with a thickness of 55.0 μm for the insulating layer in the second region. Immediately thereafter, the coated area was cured by UV irradiation (light source: UV-LED (Phoseon, product name: FJ800), wavelength: 365 nm, irradiation intensity: 30 mW / cm2, irradiation time: 20 s) in an N2 atmosphere. After curing, the cured material was heated at 120°C for 1 minute using a hot plate to remove porogenes and obtain a porous insulating layer.

[0218] [Example 7] In Example 6, the negative electrode with the porous insulating layer of Example 7 was obtained in the same manner as in Example 6, except that the thickness of the insulating layer in the second region was changed to the thickness shown in Table 1.

[0219] [Example 8] A liquid composition for resin 1 was filled into an inkjet ejector equipped with a GEN5 head, and the liquid composition was ejected onto the negative electrode substrate to form a solid image-like coated area with a film thickness of 20.0 μm. Immediately thereafter, the coated area was cured under an N2 atmosphere by UV irradiation (light source: UV-LED (Phoseon, product name: FJ800), wavelength: 365 nm, irradiation intensity: 30 mW / cm2, irradiation time: 20 s). Next, pologenes were removed by heating the cured material at 120°C for 1 minute using a hot plate.

[0220] Next, a liquid composition for inorganic solids was filled into an inkjet ejector equipped with a GEN5 head. The liquid composition was ejected into the area excluding the negative electrode area of ​​47.0 mm × 27.0 mm where resin 1 was formed to a thickness of 20.0 μm, forming a patterned coated area as shown in Figure 1, with a total insulating layer thickness of 26.0 μm in the second region. The dispersion medium was removed by heating at 120°C for 1 minute using a hot plate, and a porous insulating layer was obtained.

[0221] [Examples 9-11] In Example 8, the porous insulating layer of Examples 9 to 11 was formed in the same manner as in Example 8, except that the thickness of the insulating layer in the second region was changed to the thickness shown in Table 1.

[0222] [Example 12] A liquid composition for inorganic solids was filled into an inkjet ejector equipped with a GEN5 head. The amount of liquid composition ejected to the negative electrode was controlled to form a coated area in the pattern image shown in Figure 1, such that the insulating layer in the first region and the insulating layer in the second region had the configuration described below. Insulating layer of region 1: Area: 47.0 mm × 27.0 mm, Film thickness: 20.0 μm Insulating layer of region 2: Area: Excluding the insulating layer of region 1; Film thickness: 27.0 μm

[0223] Next, the dispersion medium was removed by heating at 120°C for 1 minute using a hot plate, thereby obtaining a porous insulating layer.

[0224] [Examples 13-15] In Example 12, the porous insulating layer of Examples 13 to 15 was formed in the same manner as in Example 12, except that the thickness of the insulating layer in the second region was changed to the thickness shown in Table 1.

[0225] [Comparative Example 1] A liquid composition for resin 1 was filled into an inkjet ejector equipped with a GEN5 head, and the liquid composition was ejected onto the negative electrode substrate to form a solid image-like coated area with a film thickness of 8.0 μm. Immediately thereafter, the coated area was cured under an N2 atmosphere by UV irradiation (light source: UV-LED (Phoseon, product name: FJ800), wavelength: 365 nm, irradiation intensity: 30 mW / cm2, irradiation time: 20 s). Next, the cured material was heated at 120°C for 1 minute using a hot plate to remove porogenes and obtain a porous insulating layer.

[0226] [Comparative Examples 2-5] In Comparative Example 1, the porous insulating layer of Comparative Examples 2 to 5 was formed in the same manner as in Comparative Example 1, except that the film thickness was changed to the film thickness shown in Table 1.

[0227] [Comparative Example 6] In Example 12, the porous insulating layer of Comparative Example 6 was formed in the same manner as in Example 12, except that the thickness of the insulating layer in the second region was changed to the thickness shown in Table 1.

[0228] <Punching out the negative electrode> The negative electrode, which had a porous insulating layer formed on it, was punched out using a die punching machine (punching area: 50.0 mm x 30.0 mm) so that the first film thickness layer was in the center.

[0229] <Positive electrode punching> The positive electrode was punched out using a die punching machine (punching area: 47.0 mm x 27.0 mm).

[0230] <Battery manufacturing> The porous insulating layer-forming negative electrode and positive electrode, punched out with a die, were laminated facing each other, and vacuum drying was performed at 120°C to remove any remaining moisture. In Example 7, the laminate produced exhibited adhesion in the insulating layer of the second region, and the laminate was integrated.

[0231] An energy storage element was fabricated by injecting an electrolyte and sealing it with a laminate outer casing. The electrolyte used was a solution in which LiPF6, the electrolyte, was added to a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) (with a mass ratio of EC:DMC = 1:1) to a concentration of 1.5 mol / L.

[0232] <Short circuit at the end due to positive electrode pressure (Evaluation 1)> The positive electrode was pressed against the end of a porous insulating layer-formed negative electrode, which had been punched out with a die, and a digital multimeter was used to check whether a short circuit occurred between the positive and negative electrodes. The criterion for determining a short circuit was whether a resistance value (less than 30 MΩ) was displayed on the digital multimeter. A: Resistance value is not displayed (30MΩ or higher) B: Resistance value is displayed (less than 30MΩ)

[0233] <Battery output characteristics (evaluation 2)> The positive and negative lead wires of the fabricated battery were connected to a charge / discharge test device, and the battery was charged at a constant current and voltage of 4.2V and a current rate of 0.2C for 5 hours. After charging was complete, it was left to stand in a 40°C constant temperature bath for 5 days. After that, it was discharged at a constant current of 0.2C down to 2.5V. Then, it was charged at a constant current and voltage of 4.2V and a current rate of 0.2C for 5 hours, with a 10-minute break in between, and then discharged at a constant current of 0.2C down to 2.5V. The discharge capacity at this time was defined as the initial capacity.

[0234] As described above, the positive and negative lead wires of the battery whose initial capacity was measured were connected to a charge / discharge test device, and it was charged at a maximum voltage of 4.2V, a current rate of 0.2C, and for 5 hours. Then, after a 10-minute break, it was discharged at a constant current rate of 0.2C for 2.5 hours to bring the lithium-ion battery to a depth of charge of 50%.

[0235] Next, pulses with current rates of 0.2C to 5.0C were discharged for 10 seconds, and the power required to reach a 2.5V cutoff voltage was calculated from the correlation line between the voltage and current after the pulse, and the output characteristics were calculated by dividing this by the cell weight.

[0236] Since the output characteristics vary depending on the material of the first film thickness layer, Examples 1 to 11 and Comparative Examples 1, 2, 4, and 5 were judged using Comparative Example 3 as a reference, and Examples 12 to 15 were judged using Comparative Example 6 as a reference, according to the following criteria. A: Reference ratio of 98% or higher B: Reference ratio less than 98%

[0237] [Table 1]

[0238] According to Table 1, Examples 1 to 5 did not short-circuit even when the positive electrode was pressed against the end, and the characteristics of the battery using the negative electrode were equivalent to those of Comparative Example 3, which serves as the reference. These effects are thought to have been achieved by keeping the insulating layer of the first region, which is the part facing the positive electrode, the same as the reference, while increasing the thickness of the insulating layer of the second region, which is around the end of the negative electrode.

[0239] Examples 6 to 11 show negative electrodes formed by two layers, with the insulating layer in the second region made of different materials. However, the end short-circuit evaluation and output characteristic evaluation results are the same as in Examples 1 to 5, indicating that the effect does not change even when the material is changed.

[0240] In Examples 12 to 15, pressing the positive electrode against the end did not cause a short circuit, and the characteristics of the battery using that negative electrode showed performance equivalent to that of Comparative Example 6, which served as the reference.

[0241] In Comparative Examples 1 and 2, the output characteristics improved compared to the reference Comparative Example 3 due to the thinner insulating layer in the first region, but a short circuit occurred when the counter electrode was pressed against the end. In Comparative Examples 4 and 5, no short circuit occurred at the end due to the pressing of the counter electrode, but a decrease in output characteristics was observed because the insulating layer in the first region was thicker than that of the reference Comparative Example 3.

[0242] Although embodiments of the present invention have been described above, the present invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope of the invention as described in the claims. [Explanation of Symbols]

[0243] 100 Printing process department 1A Printing device 1B Containment container 1C supply tube 2A light irradiation device 2B Polymerization Inert Gas Circulation System 3A heating device 4A Second electrode container 4B Second electrode transport device 5. First electrode (positive electrode) (printing substrate) 6 Liquid composition 7. Conveying section 8 Electrode base (positive electrode current collector) 9 Electrode composite material layer (positive electrode composite material layer) 91 One side 91A Peripheral area 10. Porous insulating layer (insulating layer) 10A First film thickness layer 10B Second film thickness layer 11. Second electrode (negative electrode) 11 Electrode base (negative electrode current collector) 12 Electrode composite material layer (negative electrode composite material layer) 100 Printing Process Section (Liquid Application Process) 200 Polymerization Process Section (Energy Imparting Process) 300 Heating process section 600 Insulating layer manufacturing equipment (insulating layer formation process) R1 1st area R2 2nd area W1 width T11 Thickness T12 Thickness T2 Thickness (Total film thickness) T21 Half of the total film thickness [Prior art documents] [Patent Documents]

[0244] [Patent Document 1] Japanese Patent Publication No. 2000-277386

Claims

1. An electrode element in which a positive electrode and a negative electrode are stacked in a state insulated from each other, At least one of the positive electrode or the negative electrode is Electrode substrate and, An electrode composite layer provided on the electrode substrate, The electrode composite layer comprises an insulating layer provided on one surface of the electrode composite layer, The aforementioned insulating layer is A first region including a first film thickness layer having a first thickness in a direction perpendicular to one of the aforementioned surfaces, The present invention comprises a first film thickness layer and a second region having a second film thickness layer having a second thickness in a direction perpendicular to one of the surfaces, The second region is at least a part of the peripheral edge of the one surface, The first film thickness layer is formed of a porous structure, The insulating layer is formed on the positive electrode or the negative electrode, The second thickness of the second film layer is less than or equal to half the thickness of the negative electrode or positive electrode facing the positive electrode or negative electrode on which the insulating layer is formed. An electrode element characterized by the following features.

2. The second film thickness layer is formed of a porous structure. The electrode element according to claim 1.

3. The structure of the first film thickness layer and the structure of the second film thickness layer are integrated. The electrode element according to claim 1 or 2.

4. The second film thickness layer is formed of a porous structure different from the structure of the first film thickness layer. The electrode element according to claim 1.

5. The porous structure contains an inorganic oxide bound with a binder. The electrode element according to any one of claims 1 to 4.

6. The porous structure is a resin structure with a resin backbone. The electrode element according to any one of claims 1 to 4.

7. The aforementioned resin structure has a co-continuous structure. The electrode element according to claim 6.

8. The second film thickness layer is inclined such that its width decreases as it moves away from the first region in a direction perpendicular to one of the surfaces. The electrode element according to any one of claims 1 to 7.

9. The second region is formed continuously around the entire circumference of the peripheral portion. The electrode element according to any one of claims 1 to 8.

10. The aforementioned one surface is rectangular in shape. The second region is formed on three sides of the one surface, The electrode element according to any one of claims 1 to 8.

11. The second region is formed on two sides of the one surface, The electrode element according to any one of claims 1 to 8.

12. The two sides are opposing sides on one of the faces. The electrode element according to claim 11.

13. The second region is formed discontinuously over the entire circumference of the peripheral portion. The electrode element according to any one of claims 1 to 8.

14. An electrochemical element having an electrode element according to any one of claims 1 to 13.

15. A power storage device having an electrochemical element as described in claim 14.

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