Electrochemical element and module of electrochemical element

Abstract

The utility model provides an electrochemical element with excellent reliability and a module of the electrochemical element. The electrochemical element is characterized in that the electrochemical element is provided with an outer packaging body and an electrode laminated body sealed in the outer packaging body, and the electrode laminated body is provided with a first electrode, a second electrode and an isolating layer arranged between the first electrode and the second electrode. A foamed sheet made of resin is disposed between the electrode laminate and the exterior body, and the electrode laminate is pressed by the foamed sheet. The module of the electrochemical elements is characterized in that a laminated body on which a plurality of the electrochemical elements are laminated is accommodated in a box body, and an outer packaging body of the electrochemical elements is formed by a laminated film.

Description

TECHNICAL FIELD

[0001] The utility model relates to the electrochemical element of excellent reliability and the module of above -mentioned electrochemical element. BACKGROUND

[0002] In recent years, with the development of portable electronic devices such as mobile phones, notebook personal computers, and the practicality of electric vehicles, there is a demand for small, lightweight, high-capacity, and high-energy-density batteries.

[0003] Currently, among lithium batteries that can meet this requirement, particularly lithium ion batteries, organic electrolytes containing organic solvents and lithium salts are used as non-aqueous electrolytes.

[0004] Furthermore, with the further development of lithium ion battery application devices, there is a demand for further long-life, high-capacity, and high-energy-density lithium ion batteries, and also a demand for high reliability of long-life, high-capacity, and high-energy-density lithium ion batteries.

[0005] However, the organic electrolyte used in lithium ion batteries contains organic solvents as flammable substances, so when an abnormality such as a short circuit occurs in the battery, the organic electrolyte can abnormally heat. In addition, with the recent trend of high-energy-density lithium ion batteries and the increase in the amount of organic solvents in organic electrolytes, further reliability of lithium ion batteries is required.

[0006] Under the above conditions, all-solid-state lithium batteries (all-solid-state batteries) that do not use organic solvents are attracting attention. All-solid-state batteries use a molded body of a solid electrolyte that does not use organic solvents instead of the conventional organic solvent-based electrolyte, have no concern about abnormal heating of the solid electrolyte, and have high safety.

[0007] In addition, all-solid-state batteries not only have high safety, but also have high reliability and high environmental resistance, and have a long life, so they are expected as maintenance-free batteries that contribute to social development and can also contribute to safety and security. By providing all-solid-state batteries to society, it is possible to contribute to the achievement of Goal 3 (ensuring healthy lives for people of all ages, promoting well-being), Goal 7 (ensuring access to affordable, reliable, and sustainable modern energy for all), Goal 11 (achieving inclusive, safe, resilient, and sustainable cities and human settlements), and Goal 12 (ensuring sustainable patterns of consumption and production) of the 17 goals of the Sustainable Development Goals (SDGs) established by the United Nations.

[0008] However, various external casings are used in batteries such as all-solid-state batteries. For example, Patent Document 1 proposes a battery casing that includes: an insulating substrate having a recess for housing a power generation element and two external electrodes on its bottom surface, and a cover that blocks the recess; conductive sheets, which are considered to function as current collectors, are disposed above and below the power generation element; and wiring that electrically connects one of the conductive sheets to one of the two external electrodes and wiring that electrically connects the other of the conductive sheets to the remaining one of the two external electrodes.

[0009] Furthermore, Patent Document 1 describes a method where an elastomer such as rubber (spacer) is placed between the cover and the conductive sheet, and the thickness of the spacer is greater than the gap between the cover and the conductive sheet. The elastic force of the spacer is used to press the conductive sheet against the electrodes of the power generation element for conductive connection and to fix the battery (electrode body). Additionally, it describes using thermally expandable materials such as butyl rubber as spacers, where thermal expansion of the butyl rubber after sealing the outer casing produces the same effect as described above.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: International Publication No. 2020 / 030424 Utility Model Content

[0013] Technical problem to be solved by the utility model

[0014] However, in the methods described above that use elastomers such as rubber, sealing the outer casing requires pressing the spacer with the cover to reduce its thickness, which can easily lead to a decrease in sealing performance. Furthermore, in methods using thermally expandable butyl rubber, the butyl rubber needs to be heated to a high temperature (above 200°C) to allow for thermal expansion, raising concerns about potential degradation of battery characteristics due to deterioration of the active materials and solid electrolyte.

[0015] This invention was made in view of the above circumstances, and its purpose is to provide an electrochemical element with excellent reliability, a method for manufacturing the same, and a module of the aforementioned electrochemical element.

[0016] Technical solutions to solve technical problems

[0017] The electrochemical element of this invention is characterized in that it has an outer casing and an electrode stack sealed inside the outer casing. The electrode stack has a first electrode, a second electrode, and an insulating layer between the first electrode and the second electrode. A resin foam sheet is disposed between the electrode stack and the outer casing, and the electrode stack is pressed by the foam sheet.

[0018] The module of the electrochemical element of this utility model is characterized in that a stack of multiple electrochemical elements of this utility model is housed in a box, and the outer casing of the electrochemical element is composed of a laminated film.

[0019] The electrochemical element of this invention can be manufactured by the manufacturing method of this invention. The manufacturing method of this invention is characterized by having a sealing process and a heating process. In the sealing process, an electrode stack having a first electrode, a second electrode, and an insulating layer between the first electrode and the second electrode, and a resin sheet that expands by heating are sealed into an outer casing. In the heating process, the resin sheet is heated to make it foam, and the expanded resin sheet is used to press the electrode stack.

[0020] Beneficial effects of utility model

[0021] According to this invention, it is possible to provide an electrochemical element with excellent reliability, a method for manufacturing the same, and a module for the aforementioned electrochemical element. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view schematically illustrating an example of the electrochemical element of this invention.

[0023] Figure 2 This is a schematic representation of the electrochemical element of this invention. Figure 1 Cross-sectional views of different examples.

[0024] Figure 3 It is a schematic representation of multiple stacked layers. Figure 2 The diagram shows a cross-sectional view of a module of electrochemical elements assembled into a housing. Detailed Implementation

[0025] Figure 1 The figure shows a longitudinal cross-sectional view of an example of the electrochemical element of this invention. Figure 1 The electrochemical element 100 shown is configured to have an electrode stack 110 having a first electrode 111, a second electrode 112 and an insulating layer 113 between them, and the electrode stack 110 is sealed in an outer casing formed by an outer container 140 and a cap 150.

[0026] External terminals 160 and 170 for electrical connection with the electrochemical element 100 are provided on the lower surface of the outer container 140. External terminal 160 is electrically connected via conductive path 161 to a current collector 120 located on the outer side (opposite to the insulating layer 113) of the first electrode 111 disposed in the electrode stack 110. Furthermore, external terminal 170 is electrically connected via conductive path 171 to a current collector 121 located on the outer side (opposite to the insulating layer 113) of the second electrode 112 disposed in the electrode stack 110.

[0027] Furthermore, a resin foam sheet 130 is disposed on the side of the current collector 121 opposite to the second electrode 112 (upper side in the figure) outside the second electrode 112 disposed in the electrode stack 110. The force of the expanding foam sheet 130 presses the current collector 121 and the electrode stack 110 downwards via the current collector 121. Therefore, the position of the electrode stack 110 is fixed, and the conductivity between the current collector 121, the second electrode 112, and the conductive path 171 is well maintained.

[0028] When the electrode stack 110 has a solid electrolyte layer as a separator 113, the electrode stack 110 is simply sealed inside the outer packaging. On the other hand, when the electrode stack 110 has a diaphragm as a separator 113, an electrolyte (not shown) is sealed inside the outer packaging along with the electrode stack 110.

[0029] like Figure 1 As shown, in the electrochemical element of this invention, a resin foam sheet can be disposed on one electrode side of an electrode stack having a first electrode, a second electrode, and an insulating layer between the first electrode and the second electrode, or resin foam sheets can be disposed on both sides of the electrode stack.

[0030] The aforementioned resin-based foam sheet can be formed by using a resin sheet of thickness that expands upon heating without hindering the sealing process of the outer casing, and then heating the resin sheet under appropriate conditions without affecting the properties of the active material and the solid electrolyte after sealing the outer casing. Therefore, electrochemical elements can be assembled without compromising sealing performance or properties, resulting in electrochemical elements with excellent reliability.

[0031] exist Figure 1In the electrochemical element 100 shown, a resin foam sheet 130 is disposed on the side of the current collector 121 opposite to the second electrode 112, which is disposed outside the electrode stack 110. On the other hand, no foam sheet is disposed on the side of the current collector 120, which is disposed outside the first electrode 111. However, the first electrode 111 is pressed against the current collector 120 by the force of the foam sheet 130 pressing the electrode stack 110 downwards via the current collector 121. Therefore, in Figure 1 In the electrochemical element 100 shown, the position of the electrode stack 110 is fixed by the action of the resin foam sheet 130, which can prevent positional displacement caused by vibration, etc., and can not only maintain the conduction between the second electrode 112 and the current collector 121 and the current collector 121 and the conduction path 171, but also maintain the conduction between the first electrode 111 and the current collector 120 and the current collector 120 and the conduction path 161.

[0032] It should be noted that, depending on the configuration and shape of the conduction path 161 that connects the first electrode 111 to the external terminal 160 in the figure, a resin foam sheet for pressing the current collector 120 toward the first electrode 111 can also be arranged on the side of the current collector 120 opposite to the first electrode 111 (lower side in the figure) on the outside of the first electrode 111 of the electrode stack 110.

[0033] Figure 2 A cross-sectional view is shown, schematically illustrating another example of the electrochemical element of this invention. Figure 2 The electrochemical element 200 shown is an example having an outer casing 210 made of a laminated film. In the electrochemical element 200, a first electrode 111 having a first electrode active material layer 111a containing an active material or the like and a first electrode current collector 111b, and a second electrode 112 having a second electrode active material layer 112a containing an active material or the like and a second electrode current collector 112b, are stacked together with an insulating layer 113 to form an electrode laminate 110.

[0034] exist Figure 2 The electrochemical element 200 shown also has... Figure 1 Similarly, in the case where the electrode stack 110 has a solid electrolyte layer as a separator 113, the electrode stack 110 is simply encapsulated in the outer casing 210. In the case where the electrode stack 110 has a membrane as a separator 113, the electrolyte (not shown) is encapsulated together with the electrode stack 110 in the outer casing 210.

[0035] In the first electrode 111 of the electrochemical element 200, an exposed portion is provided in the first electrode current collector 111b that does not contact the first electrode active material layer 111a. This exposed portion is led out to the outside of the outer casing 210 and constitutes a terminal portion 111c for electrical connection with the application device of the electrochemical element 200 or for electrical connection between the first electrodes of the electrochemical element when forming a module of the electrochemical element (described later). It should be noted that the terminal portion 111c of the first electrode can also be formed by connecting it to the first electrode current collector 111b using a foil, plate, wire, or other conductive material (metal, carbon, etc.) that is separate from the first electrode current collector 111b.

[0036] In addition, although Figure 2 Although not shown in the diagram, the second electrode 112 also has an exposed portion in the second electrode current collector 112b that does not contact the second electrode active material layer 112a. This exposed portion extends to the outside of the outer casing 210, forming a terminal portion for electrical connection with the application device of the electrochemical element 200 or for electrical connection between the second electrodes of the electrochemical element when forming a module of the electrochemical element (described later). It should be noted that the terminal portion of the second electrode can also be formed by connecting it to the second electrode current collector 112b using a foil, plate, wire, or other conductive material (metal, carbon, etc.) that is separate from the second electrode current collector 112b.

[0037] Furthermore, between the outer casing 210 and the electrode stack 110 ( Figure 2 Resin foam sheets 130 and 130 are disposed above and below the middle electrode laminate 110. Figure 2 In the electrochemical element 200 shown, the resin foam sheets 130, 130 can prevent the positional displacement of the components constituting the electrode stack 110 from being offset from each other, or improve the conductivity or ionic conductivity between the components.

[0038] The electrochemical element of this invention includes batteries, capacitors, etc. Furthermore, when the electrochemical element of this invention is a battery, it includes primary batteries and secondary batteries, and includes batteries having a solid electrolyte layer between the positive and negative electrodes (all-solid-state batteries) and batteries having a separator between the positive and negative electrodes and an electrolyte containing a solvent (electrolyte, gel electrolyte) (batteries other than all-solid-state batteries), etc. Furthermore, when the electrochemical element of this invention is a capacitor, it includes double-layer capacitors, lithium-ion capacitors, etc.

[0039] <Resin-based foam sheets>

[0040] In electrochemical devices, the aforementioned resin-based foam sheet can be formed as follows: During the assembly of the electrochemical device, a resin sheet capable of foaming and expanding at temperatures below 195°C is used. After sealing the outer casing, the resin sheet is heated, thereby causing it to foam and expand. It should be noted that, from the viewpoint of suppressing unintended foaming, such as during the manufacture of the electrochemical device, the minimum temperature at which the foamable resin sheet begins to foam is preferably 60°C or higher. Furthermore, the heating of the resin sheet is actually performed by heating the sealed outer casing.

[0041] As a resin sheet that can foam at temperatures below 195°C, it is preferable to use various resins that do not easily deteriorate inside the electrochemical element, such as urethane resin, epoxy resin, and silicone resin containing a foaming agent.

[0042] Regarding the foaming agent, there are no particular restrictions as long as it does not damage the properties of the electrodes (active material) or separators (diaphragm or solid electrolyte layer) of the electrochemical element when foaming the resin sheet, and is capable of foaming the resin sheet below the aforementioned temperature (more preferably, a foaming agent that cannot foam the resin sheet below the aforementioned minimum temperature). Foaming agents that have been used for foaming urethane resins, epoxy resins, silicone resins, etc., can be used. In addition, "ADVANCELL EM" (trade name) manufactured by Sekisui Chemicals Co., Ltd. can also be used as a foaming agent.

[0043] In addition, commercially available products (such as the foamed adhesive sheet "SAFB (trade name)" manufactured by Nigan Kogyo Co., Ltd.) can also be used for resin sheets that can foam at temperatures below 195°C.

[0044] From the viewpoint of being able to effectively press the current collector toward the electrode after foaming, the thickness of the foamable resin sheet used in the assembly of the electrochemical element before foaming is preferably 10 μm or more, more preferably 20 μm or more. However, if the foamable resin sheet is too thick, not only will the above-mentioned effect be saturated, but the volume occupied by components that do not participate in power generation within the electrochemical element will also increase. Accordingly, the thickness of the foamable resin sheet is preferably 2000 μm or less, more preferably 500 μm or less, and particularly preferably 100 μm or less.

[0045] Furthermore, to ensure sufficient pressure on the electrode when the foamable resin sheet is loaded into the electrochemical element and foams, the thickness of the foamable resin sheet during foaming (thickness during free expansion) in the unloaded state is preferably at least 1.1 times the thickness of the resin sheet before foaming, more preferably at least 1.2 times, and particularly preferably at least 1.5 times. The degree of thickness change of the resin sheet caused by foaming can be adjusted, for example, by changing the amount of foaming agent contained in the resin sheet.

[0046] <Electrode stack>

[0047] The electrode stack has a first electrode, a second electrode, and an insulating layer between them.

[0048] Examples of first and second electrodes include an electrode composed of a molded body containing an electrode compound containing an electrode active substance, and an electrode having the molded body as an electrode compound layer.

[0049] When using an electrochemical element with an electrode stack as a battery or a lithium-ion capacitor, either the first electrode or the second electrode is the positive electrode, and the other is the negative electrode. Alternatively, when using an electrochemical element with an electrode stack as a double-layer capacitor, the first and second electrodes can be electrodes with the same configuration.

[0050] When the electrochemical element is a battery, and one of the first and second electrodes is a positive electrode, the electrode mixture that constitutes it, i.e., the positive electrode mixture, contains positive electrode active materials, etc.

[0051] When the electrode is the positive electrode of a primary battery, the positive electrode active material can be the same material used in conventionally known non-aqueous electrolyte primary batteries, alkaline batteries, manganese batteries, etc. Specifically, examples include manganese dioxide, lithium-containing manganese oxides (e.g., LiMn3O6, composite oxides having the same crystal structure as manganese dioxide (β-type, γ-type, or a mixture of β-type and γ-type structures, etc.) and having a Li content of 3.5% by mass or less, preferably 2% by mass or less, more preferably 1.5% by mass or less, particularly preferably 1% by mass or less, and Li...), and Li... a Ti 5 / 3 Lithium-containing composite oxides such as O4 (4 / 3≤a<7 / 3); vanadium oxides; niobium oxides; titanium oxides; sulfides such as iron disulfide; fluorinated graphite; silver sulfides such as Ag2S; nickel oxides such as NiO2; silver oxide, etc.

[0052] Furthermore, when the electrode is the positive electrode of a secondary battery, the positive electrode active material can be any material previously known to have been used in non-aqueous electrolyte secondary batteries and alkaline secondary batteries. Specifically, an example is a positive electrode active material made from Li... 1-x M r Mn 2- r O4 (where M is at least one element selected from Li, Na, K, B, Mg, Ca, Sr, Ba, Ti, V, Cr, Zr, Fe, Co, Ni, Cu, Zn, Al, Sn, Sb, In, Nb, Ta, Mo, W, Y, Ru, and Rh, 0≤x≤1, 0≤r≤1) represents a spinel-type lithium manganese composite oxide, and is composed of Li r Mn（1-s-t） Ni s M t O （2-u） F v (where M is at least one element selected from Co, Mg, Al, B, Ti, V, Cr, Fe, Cu, Zn, Zr, Mo, Sn, Ca, Sr, and W, 0 ≤ r ≤ 1.2, 0 < s < 0.5, 0 ≤ t ≤ 0.5, u + v < 1, -0.1 ≤ u ≤ 0.2, 0 ≤ v ≤ 0.1) the layered compound represented by, by Li 1-x Co 1-r M r O2 (where M is at least one element selected from Al, Mg, Ti, V, Cr, Zr, Fe, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, 0 ≤ x ≤ 1, 0 ≤ r ≤ 0.5) the lithium cobalt composite oxide represented by, by Li 1-x Ni 1-r M r O2 (where M is at least one element selected from Al, Mg, Ti, Zr, Fe, Co, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, and Ba, 0 ≤ x ≤ 1, 0 ≤ r ≤ 0.5) the lithium nickel composite oxide represented by, by Li 1+s-x M 1-r N r PO4F s (where M is at least one element selected from Fe, Mn, and Co, N is at least one element selected from Al, Mg, Ti, Zr, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, V, and Ba, 0 ≤ x ≤ 1, 0 ≤ r ≤ 0.5, 0 ≤ s ≤ 1) the olivine-type composite oxide represented by, by Li 2-x M 1-r N r P2O7 (where M is at least one element selected from Fe, Mn, and Co, N is at least one element selected from Al, Mg, Ti, Zr, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb, V, and Ba, 0 ≤ x ≤ 2, 0 ≤ r ≤ 0.5) the pyrophosphate compound represented by, nickel hydroxide, silver oxide, etc., and only one of them can be used, or two or more of them can be used in combination.

[0053] When the electrochemical element is an all-solid-state secondary battery, the average particle size of the positive electrode active material is preferably 1 μm or more, more preferably 2 μm or more, and preferably 10 μm or less, more preferably 8 μm or less. It should be noted that the positive electrode active material can be primary particles or secondary particles formed by the aggregation of primary particles. Using a positive electrode active material with an average particle size within the above-mentioned range increases the number of interfaces with the solid electrolyte contained in the positive electrode, thereby further improving the battery's output characteristics.

[0054] The average particle size of various particles (positive electrode active materials, solid electrolytes, etc.) mentioned in this specification refers to the value of 50% of the diameter in the cumulative fraction of the volume reference when calculating the integral volume from the smallest particle size using a particle size distribution measuring device (such as the Microtrac particle size distribution measuring device "HRA9320" manufactured by Nikko Co., Ltd.). 50 ).

[0055] In the case of an all-solid-state secondary battery, the positive electrode active material preferably has a reaction inhibition layer on its surface to suppress the reaction with the solid electrolyte contained in the positive electrode.

[0056] Within the molded body of the electrode mixture (the molded body of the positive electrode mixture), if the positive electrode active material comes into direct contact with the solid electrolyte, the solid electrolyte will oxidize and form a resistive layer, potentially reducing the ionic conductivity within the molded body of the electrode mixture. By setting a reaction-inhibiting layer on the surface of the positive electrode active material to prevent direct contact between the positive electrode active material and the solid electrolyte, the reduction in ionic conductivity within the molded body of the electrode mixture caused by the oxidation of the solid electrolyte can be suppressed.

[0057] The reaction inhibition layer can be made of any material that has ion conductivity and can inhibit the reaction between the positive electrode active material and the solid electrolyte. Examples of materials that can constitute the reaction inhibition layer include oxides containing Li and at least one element selected from Nb, P, B, Si, Ge, Ti, and Zr. More specifically, examples include Nb-containing oxides such as LiNbO3, Li3PO4, Li3BO3, Li4SiO4, Li4GeO4, LiTiO3, LiZrO3, and Li2WO4. The reaction inhibition layer may contain only one of these oxides, or it may contain two or more, and multiple oxides can form a composite compound. Among these oxides, Nb-containing oxides are preferred, and LiNbO3 is more preferred.

[0058] The reaction inhibition layer is preferably present on the surface at a concentration of 0.1 to 1.0 parts by mass relative to 100 parts by mass of the positive electrode active material. If it is within this range, the reaction between the positive electrode active material and the solid electrolyte can be effectively inhibited.

[0059] Methods for forming a reaction-inhibiting layer on the surface of a positive electrode active material include sol-gel method, mechanical fusion method, CVD method, PVD method, ALD method, etc.

[0060] From the viewpoint of further increasing the energy density of electrochemical elements, the content of positive electrode active material in the positive electrode mixture is preferably 60-85% by mass.

[0061] The positive electrode mixture may contain conductive additives. Specific examples include carbon materials such as graphite (natural graphite, artificial graphite), graphene, carbon black, carbon nanofibers, and carbon nanotubes. It should be noted that, for example, when Ag₂S is used as the active material, conductive Ag is generated during the discharge reaction, so the positive electrode mixture may not contain conductive additives. When the positive electrode mixture contains conductive additives, if the content of the positive electrode active material is set to 100 parts by mass, its content is preferably 1.0 parts by mass or more, preferably 7.0 parts by mass or less, and more preferably 6.5 parts by mass or less.

[0062] In addition, the positive electrode mixture may contain a binder. Specific examples include fluoropolymers such as polyvinylidene fluoride (PVDF). It should be noted that, for example, in the case where the positive electrode mixture contains a sulfide-based solid electrolyte (details below), the positive electrode mixture may not contain a binder if good formability can be ensured in the molded body of the electrode mixture (the molded body of the positive electrode mixture) even without the use of a binder.

[0063] In the positive electrode mixture, when a binder is required, its content is preferably 15% by mass or less, and more preferably 0.5% by mass or more. On the other hand, in the positive electrode mixture, when moldability can be obtained even without a binder, its content is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., it does not contain a binder).

[0064] In the case of an all-solid-state battery (all-solid-state primary battery, all-solid-state secondary battery), the positive electrode mixture contains a solid electrolyte.

[0065] There are no particular limitations on the solid electrolyte contained in the positive electrode mixture, as long as it has lithium-ion conductivity. For example, sulfide-based solid electrolytes, hydride-based solid electrolytes, halide-based solid electrolytes, oxide-based solid electrolytes, etc. can be used.

[0066] Examples of sulfide-based solid electrolytes include Li₂S-P₂S₅, Li₂S-SiS₂, Li₂S-P₂S₅-GeS₂, and Li₂S-B₂S₃ glass particles. In addition, thio-LISICON-type materials (Li₂S₅-B₂S₃) have attracted considerable attention in recent years due to their high Li-ion conductivity.10 GeP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 etc. with Li 12-12a-b+c+6d-e M 1 3+a-b-c-d M 2 b M 3 c M 4 d M 5 12- e X e (where M 1 is Si, Ge or Sn, M 2 is P or V, M 3 is Al, Ga, Y or Sb, M 4 is Zn, Ca or Ba, M 5 is S, or S and O, X is F, Cl, Br or I, 0 ≤ a < 3, 0 ≤ b + c + d ≤ 3, 0 ≤ e ≤ 3), substances with a thiogermanate crystal structure.

[0067] As a hydride - based solid electrolyte, for example, LiBH4, a solid solution of LiBH4 and the following alkali - metal compounds (e.g., a solid solution with a molar ratio of LiBH4 to alkali - metal compound of 1:1 to 20:1), etc. can be cited. As the alkali - metal compound in the above solid solution, at least one selected from lithium halides (LiI, LiBr, LiF, LiCl, etc.), rubidium halides (RbI, RbBr, RbF, RbCl, etc.), cesium halides (CsI, CsBr, CsF, CsCl, etc.), lithium amide, rubidium amide, and cesium amide can be cited.

[0068] As a halide - based solid electrolyte, for example, monoclinic LiAlCl4, defective spinel - type or layered - structure LiInBr4, monoclinic Li 6-3m Y m X6 (where 0 < m < 2 and X = Cl or Br), etc. In addition, for example, well - known substances described in International Publication No. 2020 / 070958 and International Publication No. 2020 / 070955 can also be used.

[0069] As an oxide - based solid electrolyte, for example, garnet - type Li7La3Zr2O 12 、NASICON - type Li 1+ O Al 1+O Ti 2-O(PO4)3, Li 1+p Al 1+p Ge 2-p (PO4)3, perovskite-type Li 3q La 2 / 3-q TiO3, etc.

[0070] Among these solid electrolytes, sulfide-based solid electrolytes are preferred from the perspective of high lithium-ion conductivity, and sulfide-based solid electrolytes containing Li and P are more preferred. From the perspective of even higher lithium-ion conductivity and high chemical stability, sulfide-based solid electrolytes with a sulfide-silver-germanium ore-type crystal structure are even more preferred.

[0071] As a sulfide-based solid electrolyte with a sulfide-germanium sulfide crystal structure, a sulfide-based solid electrolyte containing Li, P, S and halogen elements is particularly preferred, such as Li6PS5Cl.

[0072] From the viewpoint of reducing grain boundary resistance, the average particle size of the solid electrolyte is preferably 0.1 μm or more, more preferably 0.2 μm or more. On the other hand, from the viewpoint of forming a sufficient contact interface between the active material and the solid electrolyte, it is preferably 10 μm or less, more preferably 5 μm or less.

[0073] From the viewpoint of further improving the ion conductivity within the positive electrode and further improving the output characteristics of the electrochemical element, when the content of the positive electrode active material is set to 100 parts by mass, the content of the solid electrolyte in the positive electrode mixture is preferably 10 parts by mass or more, more preferably 15 parts by mass or more. However, if the amount of solid electrolyte in the positive electrode mixture is too large, the amount of other components will decrease, and the effect brought by them may be reduced. Therefore, when the content of the positive electrode active material is set to 100 parts by mass, the content of solid electrolyte in the positive electrode mixture is preferably 65 parts by mass or less, more preferably 60 parts by mass or less.

[0074] When the electrochemical element is a battery and one of the first and second electrodes is a negative electrode, the electrode mixture that constitutes it, i.e., the negative electrode mixture, contains negative electrode active substances, etc.

[0075] Examples of anode active materials include carbon materials such as graphite, lithium titanium oxides (such as lithium titanate), elemental compounds (oxides, etc.) containing elements such as Si and Sn, and their alloys. In addition, lithium metal, lithium alloys (lithium-aluminum alloys, lithium-indium alloys, etc.), zinc, and hydrogen storage alloys can also be used as anode active materials.

[0076] From the perspective of further increasing the energy density of the battery, the content of negative electrode active material in the negative electrode mixture is preferably 40-80% by mass.

[0077] The negative electrode mixture may contain a conductive additive. Specific examples include conductive additives that are the same as those previously exemplified as substances that can be contained in the positive electrode mixture. When the content of the negative electrode active material is set to 100 parts by mass, the content of the conductive additive in the negative electrode mixture is preferably 10 to 30 parts by mass.

[0078] Furthermore, the negative electrode mixture may contain a binder. Specific examples include substances similar to the binders previously exemplified as substances that can be contained in the positive electrode mixture. It should be noted that, for example, in the case where the negative electrode mixture contains a sulfide-based solid electrolyte (described later), the negative electrode mixture may not contain a binder if good formability can be ensured in the molded body of the electrode mixture (the molded body of the negative electrode mixture) even without the use of a binder.

[0079] In the negative electrode binder, if an adhesive is required, its content is preferably 15% by mass or less, and more preferably 0.5% by mass or more. On the other hand, in the negative electrode binder, if moldability can be obtained even without an adhesive, its content is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0% by mass (i.e., it does not contain an adhesive).

[0080] In the case of an all-solid-state battery, the negative electrode mixture contains a solid electrolyte. Specific examples include substances similar to the solid electrolytes previously exemplified as substances that can be contained in the positive electrode mixture. Among the solid electrolytes exemplified above, sulfide-based solid electrolytes are preferred due to their high lithium-ion conductivity and ability to improve the formability of the negative electrode mixture; sulfide-based solid electrolytes with a sulfide-germanium sulfide crystal structure are more preferred; and solid electrolytes containing Li, P, S, and halogen elements, such as Li6PS5Cl, are even more preferred.

[0081] For the same reasons as with the positive electrode mixture, the average particle size of the solid electrolyte in the negative electrode mixture is preferably 0.1 μm or more, more preferably 0.2 μm or more, and preferably 10 μm or less, more preferably 5 μm or less.

[0082] From the viewpoint of further improving the ion conductivity within the negative electrode and further improving the output characteristics of the electrochemical element, when the content of the negative electrode active material is set to 100 parts by mass, the content of the solid electrolyte in the negative electrode mixture is preferably 30 parts by mass or more, more preferably 35 parts by mass or more. However, if the amount of solid electrolyte in the negative electrode mixture is too large, the amount of other components will decrease, and the effect brought by them may be reduced. Accordingly, when the content of the negative electrode active material is set to 100 parts by mass, the content of the solid electrolyte in the negative electrode mixture is preferably 130 parts by mass or less, more preferably 110 parts by mass or less.

[0083] In addition, when the electrochemical element is a battery, one of the first and second electrodes used as the negative electrode can also be a metal sheet that functions as the negative electrode active material, such as a lithium sheet or a lithium alloy sheet.

[0084] When the electrochemical element using the electrode stack is a double-layer capacitor, the first electrode and the second electrode can be made into an electrode having an electrode mixture formed from an electrode mixture with the same composition as the above-mentioned positive electrode mixture, except that activated carbon is used as the active material.

[0085] In addition, when the electrochemical element using the electrode stack is a lithium-ion capacitor, one of the first and second electrodes can be a positive electrode with the same structure as the first and second electrodes in a double-layer capacitor, and the other electrode can be a negative electrode with the same structure as the negative electrode in a battery.

[0086] The thickness of the first electrode and the second electrode is preferably 50~3000μm.

[0087] In an electrode stack, an insulating layer is placed between the first electrode and the second electrode. However, in batteries and capacitors that do not use electrolytes containing solvents, such as all-solid-state batteries, a solid electrolyte layer is used as the insulating layer.

[0088] As a specific example of a solid electrolyte constituting the solid electrolyte layer, one can cite solid electrolytes that are the same as those previously exemplified as substances that can be contained in the positive electrode mixture. Among the solid electrolytes exemplified above, from the perspective of high lithium-ion conductivity and improved formability, sulfide-based solid electrolytes are preferred, and sulfide-based solid electrolytes having a sulfide-germanium sulfide crystal structure are more preferred.

[0089] The solid electrolyte layer can have a porous material such as resin-based nonwoven fabric as a support.

[0090] The thickness of the solid electrolyte layer is preferably 10~200μm.

[0091] In the electrode stack used in batteries and capacitors that use electrolytes (electrolytes) containing solvents, a separator is used as an isolation layer between the first electrode and the second electrode.

[0092] As a separator, a separator with sufficient strength and the ability to retain a large amount of electrolyte is preferred. From this point of view, microporous membranes or nonwoven fabrics containing polyethylene, polypropylene or ethylene-propylene copolymers with a thickness of 10 to 50 μm and an opening ratio of 30 to 70% are preferred.

[0093] Electrode laminates can be manufactured, for example, by using a first electrode and / or a second electrode formed from a molded body of an electrode mixture obtained by pressure molding an electrode mixture, or by using a sheet of metal that functions as a negative electrode active material as the first or second electrode, and attaching them to a separately molded solid electrolyte layer, separator, etc. Alternatively, the electrode laminate can be manufactured by, for example, by placing a solid electrolyte, such as that constituting the solid electrolyte layer, into a mold, performing pressure molding to form a temporary molded body, placing an electrode mixture constituting the first electrode (or second electrode) into one side of the temporary molded body of the solid electrolyte and performing pressure molding to integrate the solid electrolyte with the temporary molded body of the first electrode (or second electrode), and then placing an electrode mixture constituting the second electrode (or first electrode) into the other side of the temporary molded body of the solid electrolyte and performing pressure molding.

[0094] In addition, when forming the first electrode and the second electrode, a current collector can be pre-configured on one side of the electrode mixture that is put into the mold, and then pressurized and molded to integrate the first electrode, the second electrode and the current collector.

[0095] <Current Collector>

[0096] The current collector located outside at least one of the first and second electrodes disposed in the electrode stack can be made of metal foil, perforated metal, mesh, expanded metal mesh, foamed metal, carbon sheet, etc.

[0097] In such current collectors, foamed porous metal materials (such as "Celmet" (registered trademark) manufactured by Sumitomo Electric Industries, Ltd.) are preferred for higher current collection efficiency. It is speculated that this is because the surfaces of the electrode mixtures of the first and second electrodes are relatively rough, but the surface of the current collector made of foamed porous metal materials is also relatively rough. Therefore, through the pressing pressure generated by the foam sheet, a portion of its surface extends from the surface of the electrode mixture to the inside, resulting in a larger contact area.

[0098] The thickness of the current collector is preferably 50~1500μm.

[0099] It should be noted that the current collector may be used independently of the first and second electrodes, but as mentioned above, it may also be used integrated with the first and second electrodes.

[0100] <Exterior body>

[0101] The outer casing of electrochemical components can be, for example... Figure 1The diagram shows an outer casing consisting of an outer container and a lid. In such an outer casing, the outer container can be made of ceramic or resin. Additionally, the lid can be made of ceramic, resin, or metal (such as iron-nickel alloys, iron-nickel-cobalt alloys, or other iron-based alloys).

[0102] In the outer container, the external terminals, the conductive paths connecting the electrodes of the electrode stack to the external terminals, can be made of metals such as manganese, cobalt, nickel, copper, molybdenum, silver, palladium, tungsten, platinum, gold, or alloys containing them.

[0103] In addition to sealing the outer container and the lid by using adhesive, when using a metal lid, the lid side of the concave part of the outer container can be pre-made of metal (iron-nickel alloy, iron-nickel-cobalt alloy, or other iron-based alloys), and then sealed by welding it to the lid.

[0104] In addition, similar to a typical coin-shaped battery, the outer container and lid can be made of metal, and the outer container and lid can be sealed by seam sealing with gaskets or by bonding with adhesive.

[0105] Furthermore, such as Figure 2 As shown, the outer casing can also be made of a laminated film. The laminated film constituting the outer casing can be a metal laminated film made by laminating a resin film (resin sheet) of nylon film (nylon 66 film, etc.) or polyester film (polyethylene terephthalate film, etc.) with a metal film (metal foil, metal plate) such as aluminum (including aluminum alloy) or stainless steel.

[0106] In the case of an outer casing made of laminated films, for example, using two laminated films or folding one laminated film back to form the outer casing, the seal can be implemented by heat-sealing the overlapping laminated films together. In this case, for the purpose of making heat-sealing easier, a heat-melting resin layer can be laminated onto the aforementioned laminated films for use in the outer casing. Examples of heat-melting resins constituting the heat-melting resin layer include modified polyolefins (modified polyolefin ionomers, etc.), polyethylene and its copolymers, polypropylene and its copolymers, etc.

[0107] The shape of the outer casing of an electrochemical element when viewed from above is not particularly limited; it can be circular, or it can be a polygon such as a quadrilateral (square, rectangle).

[0108] Electrolytes

[0109] In the case of an electrochemical element having an electrode stack with a diaphragm as an isolation layer, an electrolyte is used as described above. The electrolyte is typically a liquid electrolyte (non-aqueous electrolyte or aqueous electrolyte) using a non-aqueous or aqueous solvent. Furthermore, as the non-aqueous electrolyte, a non-aqueous electrolyte obtained by dissolving an electrolyte salt such as a lithium salt in an organic solvent is used. The organic solvent is not particularly limited; examples include linear esters such as dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and methyl propyl carbonate; cyclic esters with high dielectric constants such as ethylene carbonate, propylene carbonate, butyl carbonate, and vinylene carbonate; and mixed solvents of linear and cyclic esters. Mixed solvents with linear and cyclic esters as the main solvent are particularly suitable.

[0110] As electrolyte salts dissolved in organic solvents during the preparation of non-aqueous electrolytes, such as in the case of batteries and lithium-ion capacitors, two or more of the following can be used alone or in combination: LiPF6, LiBF4, LiAsF6, LiSbF6, LiCF3SO3, LiC4F9SO3, LiCF3CO2, Li2C2F4(SO3)2, and LiC. n F 2n+1 SO3 (n≥2), LiN(RfSO2)(Rf'SO2), LiC(RfSO2)3, LiN(RfOSO2)2 (where Rf and Rf' are fluoroalkyl groups), etc. Additionally, in the case of an electric double-layer capacitor as the electrochemical element, (C2H5)4NBF4, (C2H5)4PBF4, etc., are used as the electrolyte salt in the non-aqueous electrolyte.

[0111] There is no particular limitation on the concentration of electrolyte salt in the electrolyte, but it is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and preferably 1.7 mol / L or less, more preferably 1.5 mol / L or less.

[0112] In addition, as an aqueous electrolyte, alkaline aqueous solutions (alkaline electrolytes) composed of aqueous solutions of alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and lithium hydroxide, and aqueous solutions with a pH range of 3 or higher and 12 or lower are used.

[0113] The concentration of alkali metal hydroxide in the alkaline electrolyte can be set, for example, to 25-40% by mass.

[0114] In addition, as an aqueous solution with a pH range of 3 or higher and 12 or lower, a solution is obtained by dissolving one or more of the following in water: chlorides such as sodium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium chloride, and zinc chloride; hydroxides of alkali metals and alkaline earth metals (sodium hydroxide, potassium hydroxide, magnesium hydroxide, etc.), acetates (sodium acetate, potassium acetate, magnesium acetate, etc.), nitrates (sodium nitrate, potassium nitrate, magnesium nitrate, etc.), sulfates (sodium sulfate, potassium sulfate, magnesium sulfate, etc.), phosphates (sodium phosphate, potassium phosphate, magnesium phosphate, etc.), borates (sodium borate, potassium borate, magnesium borate, etc.), citrates (sodium citrate, potassium citrate, magnesium citrate, etc.), glutamates (monosodium glutamate, potassium glutamate, magnesium glutamate, etc.); bicarbonates of alkali metals (sodium bicarbonate, potassium bicarbonate, etc.); percarbonates of alkali metals (sodium percarbonate, potassium percarbonate, etc.); halogen-containing compounds such as fluorides; and electrolyte salts such as polycarboxylic acids.

[0115] As an electrolyte for electrochemical elements, a gel-like electrolyte can also be used, which is formed by gelling the above-mentioned electrolyte with a gelling agent composed of polymers or the like.

[0116] <Modules for Electrochemical Elements>

[0117] Electrochemical elements can be used individually, or they can be used as modules formed by housing multiple electrochemical elements in a resin, metal, or other container.

[0118] Figure 3 A cross-sectional view is shown, schematically representing an example of a module of an electrochemical element. Figure 3 The electrochemical element module 300 shown is constructed by housing a stack of three electrochemical elements 200 within a housing 310. The housing 310 includes a metal container 311 and a metal cover 312. Furthermore, the terminals 111c of the first electrodes of each electrochemical element 200 constituting the electrochemical element stack are assembled by welding or the like and connected to the inside of the container 311. That is, the metal container 311 also serves as a terminal for connecting the first electrodes of the electrochemical element module 300 (the first electrodes of each electrochemical element 200 constituting the module 300) to the application device.

[0119] Furthermore, although not shown in the figure, the second electrodes of each electrochemical element constituting module 300 are also welded or otherwise assembled and connected to the inside of the cover 312 of the housing 310. That is, the metal cover 312 also serves as a terminal for connecting the second electrodes of the electrochemical element module 300 (the second electrodes of each electrochemical element 200 constituting module 300) to the application device. Moreover, an insulating layer 313 made of resin or the like is sandwiched between the container 311 and the cover 312.

[0120] In electrochemical devices having an outer casing composed of laminated films, such as Figure 2 As shown, a resin foam sheet is disposed between the electrode laminate and the outer casing. However, in this case, in order to fully press the electrode laminate using the pressing pressure based on the foam sheet, for example, as... Figure 3 As shown, it can be configured such that multiple electrochemical elements with laminated films as outer casings are stored in a resin, metal, or other container, and the foamed sheet can be pressed against the electrochemical element module of the electrode laminate by the reaction force from the container.

[0121] Example

[0122] The present invention will now be described in detail based on embodiments. However, the following embodiments do not limit the present invention.

[0123] (Example 1)

[0124] Lithium titanate (Li4Ti5O) with an average particle size of 2 μm 12 (negative electrode active material), a sulfide-based solid electrolyte (Li) with an average particle size of 0.7 μm. 7.0 PS6Cl and graphene (conductive additive) are mixed in a mass ratio of 50:41:9 to prepare a negative electrode mixture.

[0125] Additionally, LiCoO2 (positive electrode active material) with an average particle size of 5 μm and a LiNbO3 coating layer on its surface, and a sulfide-based solid electrolyte (Li) with an average particle size of 3 μm will be used. 7.0 PS6Cl) and carbon black and vapor-grown carbon fiber (VGCF) were mixed in a mass ratio of 70:26.8:1.1:2.1 to prepare a positive electrode additive.

[0126] Next, a sulfide-based solid electrolyte (Li) with an average particle size of 0.7 μm was used. 7.0 Powder (PS6Cl) is placed into a powder molding die and pressed using a press to form a temporary molding layer for the solid electrolyte layer. Then, the aforementioned negative electrode agent is deposited on the upper surface of the temporary molding layer of the solid electrolyte layer and pressed again to form a temporary molding layer for the negative electrode.

[0127] Then, after flipping the mold upside down, the positive electrode compound is placed on the upper surface of the temporary forming layer of the solid electrolyte inside the mold (opposite to the side of the temporary forming layer with the negative electrode) and pressure is applied to form an electrode stack with a positive electrode (thickness: 900 μm) on one side and a negative electrode (thickness: 1300 μm) on the other side of the solid electrolyte layer with a thickness of 150 μm.

[0128] Pressing a nickel-based foamed metal porous body (nickel "Celmet" (registered trademark)) (thickness: 1.2 mm, porosity: 98%) from Sumitomo Electric Industries Co., Ltd., forms a porous sheet with a thickness of 0.5 mm. Next, the porous sheet is cut into 7 mm diameter pieces to create current collector 1. Similarly, the porous sheet is cut into 7 mm × 7 mm squares to create current collector 2. First, current collector 1 is inserted into the bottom of a recess in an outer container, which has a... Figure 1 The structure shown has the same cross-sectional structure, with the cover portion of the concave sidewall made of iron-nickel-cobalt alloy and the rest made of ceramic. The electrode stack is mounted on the current collector 1 with the positive electrode facing downwards. Next, after mounting the current collector 2 on the negative electrode of the electrode stack, a Nikkan Industrial Co., Ltd. foamed adhesive sheet “SAFB (trade name)” (thickness: 50μm), cut into 7mm×7mm squares, is further mounted. Then, the iron-nickel-cobalt alloy cover is placed on the sidewall of the concave portion of the outer container and welded, thereby sealing the outer casing consisting of the outer container and the cover. It should be noted that during sealing, a 100μm gap exists between the upper surface of the foamed adhesive sheet and the lower surface of the cover, allowing for unobstructed sealing.

[0129] Furthermore, when the foamed adhesive sheet used in the above assembly is heated at 150°C for more than 10 minutes without being sealed inside the outer casing, the thickness becomes 225 μm (4.5 times the thickness before heating). Therefore, it is confirmed that the foamed adhesive sheet can be transformed into a foamed sheet by heating, thereby blocking the gap and pressing the current collector and electrode stack.

[0130] Next, the sealed outer casing is heated at 150°C for 20 minutes to foam the aforementioned foamed adhesive sheet, forming a foamed sheet. This foamed sheet, with its increased thickness due to foaming, is then pressed against the current collector 1, the electrode stack, and the current collector 2, enabling the current collectors to conduct to the electrodes and the conductive paths formed in the outer casing, thus achieving… Figure 1 The electrochemical element shown.

[0131] (Comparative Example 1)

[0132] The current collectors 1 and 2 were replaced with nickel plates with a thickness of 0.5 mm. Instead of using foamed adhesive sheets, conductive adhesives were used to make conductive connections between current collectors 1 and 2 and the positive and negative electrodes, as well as conductive connections between current collectors 1 and 2 and the conductive paths formed in the outer container. Otherwise, the electrochemical element was fabricated in the same manner as in Example 1.

[0133] Each of the fabricated electrochemical elements was charged and discharged, and the discharge capacity and internal resistance were measured. The results confirmed that the electrochemical elements of the examples had the same characteristics as the electrochemical elements of the comparative examples, and there was no reduction in sealing or performance.

[0134] (Example 2)

[0135] <Preparation of Solid Electrolyte Tablets>

[0136] A slurry with a solid content of 40% was prepared by mixing sulfide-based solid electrolyte (Li6PS5Cl) particles with an average particle size of 1 μm, an acrylic resin binder, and a dispersant in a mass ratio of 100:3:1 with xylene ("super-dehydrating" grade) as a solvent. The slurry was then subjected to a process with a thickness of 15 μm and a unit area weight of 8 g / m². 2 The PET nonwoven fabric was further coated with a paste using an applicator with a 40 μm gap, and then vacuum dried at 120°C for 1 hour to obtain a solid electrolyte sheet. In the solid electrolyte sheet, the binder accounts for 2.9% by mass of the total amount of solid electrolyte particles and binder.

[0137] <The Making of the Positive Electrode>

[0138] LiNi alloy with an average particle size of 3 μm and an amorphous composite oxide layer of Li and Nb formed on its surface. 0.6 Co 0.2 Mn 0.2 O2, a sulfide-based solid electrolyte (Li6PS5Cl), carbon nanotubes (Showa Denko Co., Ltd.'s "VGCF" (trade name)) as a conductive aid, and an acrylic resin binder were mixed with xylene ("super-dehydrating" grade) as a solvent in a mass ratio of 70:24:3:3 to prepare a slurry with a solid content of 60%. This slurry was coated onto a 20 μm thick Al foil current collector pre-attached with current collector tabs and vacuum dried at 120 °C to obtain the positive electrode.

[0139] <Making the Negative Electrode>

[0140] A slurry with a solid content of 50% was prepared by mixing graphite with an average particle size of 20 μm, a sulfide-based solid electrolyte (Li6PS5Cl), carbon nanotubes ("VGCF" manufactured by Showa Denko Co., Ltd.) as a conductive aid, and an acrylic resin binder in a mass ratio of 50:44:3:3 with xylene ("super-dehydrating" grade) as a solvent. This slurry was coated onto a 20 μm thick SUS foil current collector pre-attached with current collector tabs and vacuum-dried at 120 °C to obtain the negative electrode.

[0141] Assembly of Electrochemical Components

[0142] The aforementioned positive electrode, negative electrode, and solid electrolyte sheet are overlapped with their respective current collectors on the outside and the solid electrolyte sheet positioned between the two electrodes, at a speed of 10 tons / cm². 2 The electrode laminate is obtained by pressing and integrating the electrode, and cutting it to a size of 30mm×40mm after removing the portion of the collector tab.

[0143] In the current collector lugs of each electrode in the aforementioned electrode stack, a sealing film is installed at the location where it is held and heat-fused by the aluminum laminate film. Then, a foamed adhesive sheet, identical to that in Example 1, is cut into 30mm x 40mm pieces and overlapped onto the electrode stack. Both pieces are inserted into the inner side of the centrally bent aluminum laminate film, clamping and fixing the entire assembly from both sides. Next, the three outer edges of the aluminum laminate film are heat-sealed to form an outer casing. Excess sealing portions are cut off. Except for the connection configuration between the current collectors and terminals of the positive and negative electrodes, the assembly is manufactured to resemble... Figure 2 Electrochemical elements with the same structure as shown.

[0144] <Fabrication of Electrochemical Component Modules>

[0145] After being housed in the aforementioned stainless steel housing, the laminated body is heated at 150°C for 20 minutes to foam the aforementioned foamed adhesive sheet, forming a foamed sheet. Before heating, there is a gap of approximately 300 μm between the laminated body and the housing; however, the foamed sheet, having increased in thickness through foaming, blocks this gap, and by pressing each electrode laminate together, a result can be obtained... Figure 3 A module of an electrochemical element with the same structure as shown.

[0146] (Comparative Example 2)

[0147] Instead of overlapping the foamed adhesive sheet onto the electrode stack, the electrode stack is inserted into the inside of the aluminum laminate and the aluminum laminate is heat-sealed. Otherwise, the electrochemical element is fabricated in the same manner as in Example 2.

[0148] Three of the above electrochemical elements are stacked to form a laminate. The two sides of the laminate are fixed to a fixture and pressed with 0.2 MPa to obtain a module of electrochemical elements.

[0149] (Comparative Example 3)

[0150] Three electrochemical elements identical to those in Comparative Example 2 were stacked to form a laminate. The two sides of the laminate were fixed to a fixture, but the laminate was not pressed to form a module of electrochemical elements.

[0151] The modules of the electrochemical elements of Example 2, Comparative Example 2 and Comparative Example 3 were charged and discharged, and the discharge capacity and internal resistance were measured. The results confirmed that the module of the electrochemical element of Example 2 had the same characteristics as the module of the electrochemical element of Comparative Example 2, and the function was fully utilized based on the pressing of the foam sheet on the electrode stack.

[0152] On the other hand, the electrochemical element module of Comparative Example 3 did not have the electrode stack pressed, resulting in a decrease in discharge capacity and an increase in internal resistance.

[0153] This invention can be implemented in ways other than those described above without departing from its spirit. The embodiments disclosed in this application are examples, and this invention is not limited to these embodiments. The scope of this invention is preferably interpreted by the appended claims compared to the description in the foregoing specification, and all modifications within the scope of the claims are included in the claims.

[0154] Industrial availability

[0155] The electrochemical element of this invention can be used for the same purposes as conventionally known electrochemical elements, and the module of the electrochemical element of this invention can be used for the same purposes as the module of conventionally known electrochemical elements.

[0156] Explanation of reference numerals in the attached figures

[0157] 100, 200: Electrochemical element; 110: Electrode stack; 111: First electrode; 111a: First electrode active material layer; 111b: First electrode current collector; 111c: Terminal portion of the first electrode; 112: Second electrode; 112a: Second electrode active material layer; 112b: Second electrode current collector; 113: Isolation layer; 120, 121: Current collector; 130: Resin foam sheet; 140: Outer container; 150: Cover; 160, 170: External terminal; 161, 171: Conductive path; 300: Module of electrochemical element; 310: Box; 311: Container; 312: Cover; 313: Insulating layer.

Claims

1. An electrochemical element, characterized in that, It has an outer casing and an electrode stack sealed inside the outer casing. The electrode stack has a first electrode, a second electrode, and an insulating layer between the first electrode and the second electrode. A resin foam sheet is disposed between the electrode laminate and the outer casing. A current collector is disposed between the electrode laminate and the foam sheet. The foam sheet presses the electrode stack via the current collector.

2. The electrochemical element according to claim 1, characterized in that, The isolation layer is a solid electrolyte layer.

3. The electrochemical element according to claim 1, characterized in that, The foam sheet is formed by heating a resin sheet that has expanded by heating.

4. A module for an electrochemical element, characterized in that, It is a stacked body composed of multiple electrochemical elements as described in any one of claims 1 to 3, housed within a box. The outer casing of the electrochemical element is composed of a laminated film.

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