Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/78—Cases; Housings; Encapsulations; Mountings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
  • H01M50/105—Pouches or flexible bags
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
  • H01M50/117—Inorganic material
  • H01M50/119—Metals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
  • H01M50/121—Organic material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
  • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
  • H01M50/126—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers
  • H01M50/128—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers with two or more layers of only inorganic material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/116—Primary casings; Jackets or wrappings characterised by the material
  • H01M50/124—Primary casings; Jackets or wrappings characterised by the material having a layered structure
  • H01M50/126—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers
  • H01M50/129—Primary casings; Jackets or wrappings characterised by the material having a layered structure comprising three or more layers with two or more layers of only organic material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
  • H01M50/133—Thickness
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/131—Primary casings; Jackets or wrappings characterised by physical properties, e.g. gas permeability, size or heat resistance
  • H01M50/134—Hardness
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/10—Primary casings; Jackets or wrappings
  • H01M50/147—Lids or covers
  • H01M50/166—Lids or covers characterised by the methods of assembling casings with lids
  • H01M50/171—Lids or covers characterised by the methods of assembling casings with lids using adhesives or sealing agents
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to an exterior film for an electricity storage device and an electricity storage device.
• Patent Document 1 discloses an example of an electricity storage device.
• This electricity storage device includes an electrode stack and an exterior body that houses the electrode stack.
• the exterior body has a cylindrical laminate film exterior body that covers at least both end faces in the stacking direction of the electrode stack and a pair of opposing side faces, and an inner lid that is placed on the opening of the laminate film exterior body.
• the laminate film for example, an integrally molded product of metal or resin and an aluminum sheet is used. According to Patent Document 1, an electricity storage device including such an exterior body is advantageous from the viewpoint of miniaturizing the electricity storage device and improving structural efficiency.
• the laminate film when attempting to increase the size of an electricity storage device, the laminate film is required to have internal pressure resistance capable of withstanding an increase in pressure inside the electricity storage device.
• the internal pressure resistance of the laminate film it is possible to increase the thickness of the metal layer contained therein or to use a metal material with high mechanical strength as the metal constituting the metal layer. In other words, it is possible to improve the rigidity of the laminate film.
• a process of wrapping the electrode stack with a laminate film may be performed. In such a case, if the bending rigidity of the laminate film is higher than necessary, it becomes difficult to make the laminate film conform to the shape of the electrode stack. As a result, it may become difficult to properly wrap the electrode stack during the manufacturing process of the electricity storage device.
• the present invention aims to provide an exterior film for the exterior body of an electricity storage device that maintains shape conformability while improving internal pressure resistance.
• the exterior film according to the first aspect of the present invention is an exterior film for forming an exterior body of an electricity storage device, and comprises an outer resin layer, at least two metal layers made of a metal material, and at least one intermediate resin layer.
• the outer resin layer is made of a resin composition.
• the at least two metal layers are arranged on the first surface side of the outer resin layer, and have a first metal layer and a second metal layer.
• the at least one intermediate resin layer is laminated between the first metal layer and the second metal layer, and is made of a resin composition.
• the maximum thickness of each of the at least two metal layers is 200 ⁇ m or less.
• the exterior film according to the second aspect of the present invention is the exterior film according to the first aspect, in which the metal material contains at least one of an aluminum alloy, a titanium alloy, steel, copper, a nickel alloy, a magnesium alloy, niobium, and iron.
• the exterior film according to the third aspect of the present invention is the exterior film according to the first or second aspect, and the resin composition constituting the at least one intermediate resin layer contains at least one of polyurethane-based resin, polyester-based resin, polybutadiene-based resin, acid-modified polyolefin-based resin, styrene-based elastomer, acrylic-based resin, silicone-based resin, ether-based resin, and ethylene-based copolymer.
• the exterior film according to the fourth aspect of the present invention is an exterior film according to any one of the first to third aspects, in which the intermediate resin layer contains a filler.
• the exterior film according to the fifth aspect of the present invention is an exterior film according to any one of the first to fourth aspects, in which the first metal layer and the second metal layer are made of the same metal material, and the thickness of the first metal layer and the thickness of the second metal layer are substantially the same.
• the exterior film according to the sixth aspect of the present invention is an exterior film according to any one of the first to fifth aspects, in which the first metal layer and the second metal layer are made of the same metal material, the first metal layer is disposed closer to the first surface than the second metal layer, and the thickness of the first metal layer is smaller than the thickness of the second metal layer.
• the exterior film according to the seventh aspect of the present invention is an exterior film according to any one of the first to sixth aspects, in which the first metal layer is disposed closer to the first surface than the second metal layer, and the value obtained by multiplying the thickness of the first metal layer by the Young's modulus of the metal material constituting the first metal layer is smaller than the value obtained by multiplying the thickness of the second metal layer by the Young's modulus of the metal material constituting the second metal layer.
• the exterior film according to the eighth aspect of the present invention is an exterior film according to any one of the first to seventh aspects, in which the total thickness of each of the at least two metal layers is 300 ⁇ m or less.
• the exterior film according to the ninth aspect of the present invention is an exterior film according to any one of the first to eighth aspects, in which the sum of the thickness of each of the at least two metal layers and the thickness of the at least one intermediate resin layer is 300 ⁇ m or less.
• the energy storage device comprises an electrode body and an exterior body that seals the electrode body.
• the exterior body has an exterior film that wraps the electrode body and at least one lid that seals the electrode body together with the exterior film.
• the exterior film comprises an outer resin layer, at least two metal layers made of a metal material, and at least one intermediate resin layer.
• the outer resin layer is made of a resin composition.
• the at least two metal layers are arranged on the first surface side of the outer resin layer and have a first metal layer and a second metal layer.
• the at least one intermediate resin layer is laminated between the first metal layer and the second metal layer and is made of a resin composition.
• the maximum thickness of each of the at least two metal layers is 200 ⁇ m or less.
• the electric storage device is the electric storage device according to the tenth aspect, in which the metal material contains at least one of an aluminum alloy, a titanium alloy, steel, copper, a nickel alloy, a magnesium alloy, niobium, and iron.
• the electricity storage device is the electricity storage device according to the tenth or eleventh aspect, in which the resin composition constituting the at least one intermediate resin layer contains at least one of polyurethane-based resin, polyester-based resin, polybutadiene-based resin, acid-modified polyolefin-based resin, styrene-based elastomer, acrylic-based resin, silicone-based resin, ether-based resin, and ethylene-based copolymer.
• the electricity storage device is an electricity storage device according to any one of the tenth to twelfth aspects, in which the intermediate resin layer contains a filler.
• the energy storage device is an energy storage device according to any one of the tenth to thirteenth aspects, in which the first metal layer and the second metal layer are made of the same metal material, and the thickness of the first metal layer and the thickness of the second metal layer are the same.
• the energy storage device is an energy storage device according to any one of the tenth to thirteenth aspects, in which the first metal layer and the second metal layer are made of the same metal material, the first metal layer is disposed closer to the first surface than the second metal layer, and the thickness of the first metal layer is smaller than the thickness of the second metal layer.
• the energy storage device is an energy storage device according to any one of the tenth to thirteenth aspects, in which the first metal layer is disposed closer to the first surface than the second metal layer, and the value obtained by multiplying the thickness of the first metal layer by the Young's modulus of the metal material constituting the first metal layer is smaller than the value obtained by multiplying the thickness of the second metal layer by the Young's modulus of the metal material constituting the second metal layer.
• the energy storage device according to the seventeenth aspect of the present invention is an energy storage device according to any one of the tenth to sixteenth aspects, in which the total thickness of each of the at least two metal layers is 300 ⁇ m or less.
• the electric storage device is an electric storage device according to any one of the tenth to seventeenth aspects, in which the sum of the thickness of each of the at least two metal layers and the thickness of the at least one intermediate resin layer is 300 ⁇ m or less.
• the exterior film for the exterior body of an electricity storage device improves the internal pressure resistance of the exterior body of the electricity storage device constructed using the film, while ensuring sufficient shape conformability. As a result, the electrode body can be properly wrapped, improving the quality of the electricity storage device.
• FIG. 1 is a perspective view of an electricity storage device according to an embodiment.
• FIG. 2 is a perspective view of an electrode body included in the electricity storage device of FIG. 1 .
• 2 is a cross-sectional view showing an example of the configuration of an exterior film included in the electricity storage device of FIG. 1 .
• 4 is a cross-sectional view showing another example of the configuration of an exterior film included in the electricity storage device of FIG. 1 .
• FIG. 2 is a perspective view of a lid provided in the electricity storage device of FIG. 1 . 4 is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1 .
• 5A to 5C are diagrams illustrating partial steps of a manufacturing method for an electricity storage device.
• 5A to 5C are diagrams showing an example of an intermediate state of an exterior film in a manufacturing method for an electricity storage device.
• FIG. 1 is a perspective view showing a schematic diagram of an electric storage device 10 including an exterior film 50 according to the present embodiment
• FIG. 2 is a perspective view of an electrode body 20 included in the electric storage device 10.
• the exterior film 50 wraps the electrode body 20 and is preferably used to configure an exterior body 40 of the electric storage device 10.
• FIG. 3 is a cross-sectional view showing a layer structure of the exterior film 50.
• FIG. 4 is a perspective view of a lid body 60 included in the electric storage device 10.
• the direction of the arrow UD indicates the thickness direction of the electric storage device 10
• the direction of the arrow LR indicates the width direction of the electric storage device
• the direction of the arrow FB indicates the depth direction of the electric storage device 10.
• the directions indicated by the arrows UDLRFB are common to the subsequent figures.
• the power storage device 10 includes an electrode body 20, an electrode terminal 30, and an exterior body 40.
• the electrode body 20 includes electrodes (positive and negative electrodes) constituting a power storage member such as a lithium ion battery, a capacitor, an all-solid-state battery, a semi-solid battery, a quasi-solid battery, a polymer battery, an all-resin battery, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, a polyvalent cation battery, or a capacitor, as well as a separator.
• the shape of the electrode body 20 is an approximately rectangular parallelepiped.
• approximately rectangular parallelepiped includes not only a perfect rectangular parallelepiped, but also a solid body that can be regarded as a rectangular parallelepiped by modifying the shape of a portion of the outer surface, for example.
• the shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.
• the electrode body 20 has a front surface 21, a back surface 22, an upper surface 23, a lower surface 24, a first side surface 25, and a second side surface 26.
• the front surface 21 faces one of the lid bodies 60 (lid body 60A).
• the back surface 22 faces the other lid body 60 (lid body 60B).
• the upper surface 23, the lower surface 24, the first side surface 25, and the second side surface 26 respectively constitute the upper surface 41, the lower surface 42, the first side surface 43, and the second side surface 44 of the exterior body 40 described below.
• the power storage device 10 includes two electrode terminals 30.
• the electrode terminals 30 are metal terminals used for inputting and outputting electric power in the electrode body 20.
• One end of the electrode terminal 30 is electrically connected to an electrode (positive or negative) included in the electrode body 20.
• the other end of the electrode terminal 30 protrudes outward from, for example, an edge of the exterior body 40.
• the electrode terminal 30 only needs to be capable of inputting and outputting electric power to and from the electrode body 20, and may not, for example, protrude from the exterior body 40.
• the lid body 60 described below is made of, for example, a metal
• the lid body 60 may also function as the electrode terminal 30.
• the lid body 60 functioning as an electrode terminal may or may not protrude from the exterior body 40.
• the metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, or copper.
• the electrode terminal 30 connected to the positive electrode is usually made of aluminum
• the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, or the like.
• the outermost layer of the electrode body 20 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator.
• the exterior body 40 seals the electrode body 20.
• the exterior body 40 according to this embodiment includes an exterior film 50 and a lid 60.
• the exterior film 50 according to this embodiment wraps the electrode body 20.
• the lid 60 is disposed on the side of the electrode body 20 and seals the electrode body 20 together with the exterior film 50.
• the exterior film 50 is wrapped around the electrode body 20 so as to form a pair of openings 50X (see FIG. 7).
• the lid 60 is disposed on the side of the electrode body 20 so as to close the openings 50X.
• the exterior film 50 may be in a cylindrical state so as to form the openings 50X, or may be in a cylindrical state with at least a portion temporarily fixed so as to maintain this state, and the electrode body 20 may be housed inside the exterior film 50, and then the exterior film 50 may be tightly wrapped around the electrode body 20, and the openings 50X may then be closed by the lid 60.
• the electrode terminal 30 is preferably bonded with an adhesive film 31 from the viewpoint of favorable adhesion to the lid 60.
• the adhesive film 31 can be selected from any film that can bond the electrode terminal 30 made of metal and the lid 60 made of resin.
• the adhesive film 31 can be, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride.
• the adhesive film 31 can be a single layer or two or more layers of these films. In this embodiment, the adhesive film 31 is bonded to almost the entire portion of the electrode terminal 30 that is covered by the lid 60.
• a storage section for example, there is a method of forming a storage section (recess) in the exterior film 50 through cold forming to accommodate the electrode body 20.
• the exterior body 40 seals the electrode body 20 by wrapping the exterior film 50 around the electrode body 20, so that the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20.
• the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20.
• the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20.
• the exterior film 50 is a laminate (laminate film) having multiple layers stacked together.
• the exterior film 50 has an outer resin layer 51, a first adhesive layer 52, a first metal layer 53A, an intermediate resin layer 54, a second metal layer 53B, a second adhesive layer 55, and a heat-sealable resin layer 56, in this order.
• the outer resin layer 51 has a first surface 511 and a second surface 512 opposite to the first surface.
• the second surface 512 is a surface that faces outward when the exterior film 50 constitutes the exterior body 40.
• the first surface 511 is a surface that faces inward when the exterior film 50 constitutes the exterior body 40.
• the first adhesive layer 52, the first metal layer 53A, the intermediate resin layer 54, the second metal layer 53B, the second adhesive layer 55, and the heat-sealable resin layer 56 are arranged on the first surface 511 side of the outer resin layer 51.
• the outer resin layer 51 is disposed on the outer casing 40 outside the other layers of the exterior film 50.
• the exterior film 50 may include at least the outer resin layer 51, the first metal layer 53A, the intermediate resin layer 54, and the second metal layer 53B.
• the overall thickness of the exterior film 50 can be selected arbitrarily as long as the maximum thickness of each of the first metal layer 53A and the second metal layer 53B described below is 200 ⁇ m or less. From the viewpoint of strength, the thickness of the exterior film 50 is preferably 50 ⁇ m or more. From the viewpoint of formability or conformability, the thickness of the exterior film 50 is preferably 1200 ⁇ m or less. The thickness of the exterior film 50 is preferably within the range of 50 ⁇ m or more and 1200 ⁇ m or less.
• the outer resin layer 51 is a layer composed of a resin composition.
• a layer composed of a resin composition means that the content of the resin composition contained in the layer is 80% by mass or more of the entire layer, preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more.
• the layer may be composed of fillers, additives, etc. in addition to the resin composition.
• the outer resin layer 51 of this embodiment imparts heat resistance to the exterior film 50 and suppresses the occurrence of pinholes that may occur during processing or distribution.
• the outer resin layer 51 may have multiple layers composed of one or more resin compositions.
• the outer resin layer 51 of this embodiment has a first resin layer 51A and a second resin layer 51B.
• the first resin layer 51A is a stretched polyester-based resin layer. From the viewpoint of increasing the tensile elongation of the exterior film 50, the first resin layer 51A is preferably a biaxially stretched polyester-based resin layer. Furthermore, from the viewpoint of excellent puncture strength or impact strength, the first resin layer 51A is more preferably a biaxially stretched polyethylene terephthalate (PET) film. In other words, the resin composition constituting the first resin layer 51A is preferably a polyester-based resin, and among them, polyethylene terephthalate is more preferable.
• PET polyethylene terephthalate
• the second resin layer 51B is a stretched polyamide resin layer. From the viewpoint of increasing the tensile elongation of the exterior film 50, the second resin layer 51B is preferably a biaxially stretched polyamide resin layer. Furthermore, from the viewpoint of excellent puncture strength or impact strength, the second resin layer 51B is more preferably a biaxially stretched nylon (ONy) film.
• the resin composition constituting the first resin layer 51A is preferably a polyamide resin, and more preferably nylon.
• the first resin layer 51A and the second resin layer 51B may be bonded via an adhesive, or may be directly laminated without an adhesive.
• the outer resin layer 51 may further have an adhesive layer that is disposed between the first resin layer 51A and the second resin layer 51B and is made of an adhesive.
• the first resin layer 51A and the second resin layer 51B when they are bonded without an adhesive, they may be bonded in a thermally molten state, for example, by a co-extrusion method, a sand lamination method, a thermal lamination method, or the like.
• the thickness of the outer resin layer 51 is preferably, for example, 5 to 300 ⁇ m, and more preferably 5 to 150 ⁇ m.
• the outer resin layer 51 does not necessarily have to have both the first resin layer 51A and the second resin layer 51B, and one of them can be omitted.
• the outer resin layer 51 may have at least one of a coating layer made of a coating agent, a printing layer on which ink is laminated, and a buffer layer, which will be described later.
• the first adhesive layer 52 is a layer formed of an adhesive that bonds the second resin layer 51B and the first metal layer 53A of the outer resin layer 51.
• the adhesive used to form the first adhesive layer 52 is not particularly limited as long as it is an adhesive that can bond the second resin layer 51B and the first metal layer 53A, and may be a two-component curing adhesive or a one-component curing adhesive.
• the first adhesive layer 52 may be omitted.
• the first metal layer 53A and the second metal layer 53B are barrier layers that prevent at least the intrusion of moisture, and are made of a metal material.
• a layer made of a metal material means that the content of the metal material contained in the layer is 80 mass% or more of the entire layer, preferably 90 mass% or more, more preferably 95 mass% or more, and even more preferably 98 mass% or more.
• the metal materials that make up the first metal layer 53A and the second metal layer 53B may be the same as each other or different from each other. Examples of metal materials include aluminum alloys, titanium alloys, steel (including stainless steel), copper, nickel alloys, magnesium alloys, niobium, and iron, and among them, aluminum alloys or stainless steel are preferred.
• the first metal layer 53A and the second metal layer 53B may each be made of a metal foil or a metal vapor deposition film. In terms of processability such as moisture resistance and ductility, and cost, aluminum alloy foil or stainless steel foil is preferred.
• the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving formability or conformability, it is preferably an aluminum alloy foil containing iron.
• the iron content is preferably 0.1 to 9.0 mass%, and more preferably 0.5 to 2.0 mass%.
• the soft aluminum alloy foil examples include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as necessary. Softening can be performed by annealing or the like. From the viewpoint of improving the mechanical strength of the exterior film 50, it is more preferable that the aluminum alloy foil is a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy.
• the hard aluminum alloy foil examples include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.
• the aluminum alloy foil as the metal material constituting at least one of the first metal layer 53A and the second metal layer 53B is preferably an aluminum alloy foil containing magnesium.
• the magnesium content is preferably 0.2 to 5.6% by mass, and more preferably 0.2 to 3.0% by mass.
• Examples of aluminum alloy foils containing magnesium include aluminum alloy foils having compositions specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.
• 5000-series aluminum alloy foils are preferred from the viewpoint of excellent corrosion resistance.
• 5000-series aluminum alloy foils are aluminum-magnesium alloy foils that contain 0.5 to 5.6 mass% magnesium relative to the entire alloy foil (100 mass%).
• stainless steel foil examples include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior film 50 with excellent formability or conformability, it is preferable that the stainless steel foil is made of austenitic stainless steel.
• austenitic stainless steels that make up the stainless steel foil include SUS304, SUS301, and SUS316L. From the viewpoint of improving the mechanical strength of the exterior film 50 (particularly the internal pressure resistance of the exterior body 40), SUS301 is particularly preferred.
• At least one of the first metal layer 53A and the second metal layer 53B may contain a recycled metal material as the above-mentioned metal material.
• recycled metal materials include recycled materials of aluminum alloys, titanium steel, copper, nickel alloys, magnesium alloys, niobium, and iron or steel (including stainless steel). These recycled materials can be obtained by known methods. Recycled aluminum alloys can be obtained, for example, by the manufacturing method described in International Publication No. 2022/092231.
• At least one of the first metal layer 53A and the second metal layer 53B may be composed of only recycled materials, or may be composed of a mixed material of recycled materials and virgin materials.
• recycled metal materials refer to metal materials that have been made reusable by collecting, isolating, and refining various products used in the city and waste materials from manufacturing processes. Also, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.
• the thickness t1 of the first metal layer 53A and the thickness t2 of the second metal layer 53B are preferably, for example, 4 to 200 ⁇ m, more preferably 10 to 150 ⁇ m, and even more preferably 15 to 120 ⁇ m, from the viewpoints of barrier properties, pinhole resistance, and packaging suitability (particularly, flexibility when wrapping the exterior film 50 around the electrode body 20).
• the thicknesses t1 and t2 are each 4 ⁇ m or more, the exterior film 50 is less likely to break even when stress is applied by the packaging process.
• the thicknesses t1 and t2 are each 200 ⁇ m or less, the mass increase of the exterior film 50 can be reduced, and a decrease in the weight energy density of the electricity storage device 10 can be suppressed.
• the thickness t1 of the first metal layer 53A may be substantially the same as the thickness t2 of the second metal layer 53B, or may be different.
• the first metal layer 53A and the second metal layer 53B are made of the same metal material and the thicknesses t1 and t2 are different, it is preferable that t1 ⁇ t2.
• the packaging suitability of the exterior film 50 is improved.
• the exterior film 50 has an additional metal layer in addition to the first metal layer 53A and the second metal layer 53B, it is preferable that the thickness of the metal layer located on the outer side of the exterior body 40 is smaller. Note that the thickness t1 of the first metal layer 53A and the thickness t2 of the second metal layer 53B are substantially the same means that the difference between t1 and t2 is within ⁇ 2.0 ⁇ m.
• the sum of these is within 300 ⁇ m.
• the sum of the thickness t1 and the thickness t2 is equal to or less than the above upper limit, it is possible to increase the internal pressure resistance of the exterior film 50 while maintaining sufficient shape conformability.
• the exterior film 50 has a further metal layer in addition to the first metal layer 53A and the second metal layer 53B, it is preferable that the sum of the thicknesses of all the metal layers is equal to or less than the above upper limit.
• the thicknesses t1 and t2 are determined by the following procedure. (1) A sample of the target exterior film 50 is subjected to a microtome, and five test pieces are prepared by cutting out the layer cross sections of the sample. (2) An image of a cross section at any one location of the test piece is taken with a laser microscope (e.g., a combination of a controller VK-X3000 and a head unit VK-X3050 manufactured by KEYENCE Corporation) to obtain image data of the cross section of the test piece.
• a laser microscope e.g., a combination of a controller VK-X3000 and a head unit VK-X3050 manufactured by KEYENCE Corporation
• the first metal layer 53A and the second metal layer 53B in the cross section of the test piece are identified, and their thicknesses are derived using an image analysis program (e.g., multi-file analysis application VK-X3050, manufactured by KEYENCE Corporation).
• the thicknesses t1 and t2 are average values of the thicknesses calculated from five test pieces.
• the value P1 obtained by multiplying the thickness t1 ( ⁇ m) of the first metal layer 53A by the Young's modulus Y1 (N/m 2 ) of the metal material constituting the first metal layer 53A is smaller than the value P2 obtained by multiplying the thickness t2 ( ⁇ m) of the second metal layer 53B by the Young's modulus Y2 (N/m 2 ) of the metal material constituting the second metal layer 53B.
• the shape followability of the exterior film 50 is improved, and the packaging suitability of the exterior film 50 can be sufficiently ensured even if the layers made of metal materials are multilayered.
• the exterior film 50 only needs to have at least two metal layers (barrier layers), and may have an additional metal layer in addition to the first metal layer 53A and the second metal layer 53B.
• the value obtained by multiplying the thickness of the metal layer located further outward in the exterior body 40 by the Young's modulus of the metal material constituting that metal layer is smaller.
• the Young's moduli Y1 and Y2 are measured by a static test (tensile test) under an environment of 23 ⁇ 5°C and 50 ⁇ 30% RH. More specifically, a test piece of a metal material is prepared, which has a dumbbell No. 7 shape as specified in JIS K6251, a width of the central parallel part of 2.0 mm, a gauge length of 10 mm, and a thickness of the parallel part of 1.0 mm. Both ends of the test piece are set in a tensile tester, and a tensile force is applied at a tensile speed of 50 mm/min. The elongation of the test piece is measured using a pressing type displacement meter, and the Young's moduli Y1 and Y2 are calculated from the gradient of the load-elongation curve according to formula (6) specified in JIS Z2280-1993.
• first metal layer 53A and the second metal layer 53B are aluminum foil
• a corrosion-resistant film may be provided at least on the surface on the intermediate resin layer 54 side to prevent dissolution or corrosion.
• At least one of the first metal layer 53A and the second metal layer 53B may have a corrosion-resistant film on both sides.
• the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on at least one of the first metal layer 53A and the second metal layer 53B by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of at least one of the first metal layer 53A and the second metal layer 53B.
• corrosion resistance e.g., acid resistance, alkali resistance, etc.
• the corrosion-resistant film means a film (acid-resistant film) that improves the acid resistance of at least one of the first metal layer 53A and the second metal layer 53B, a film (alkali-resistant film) that improves the alkali resistance of at least one of the first metal layer 53A and the second metal layer 53B, and the like.
• the corrosion-resistant film may be formed by one type of treatment or by a combination of two or more types. In addition, it is possible to form not only one layer but also multiple layers.
• the hydrothermal conversion treatment and the anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may be included in the definition of chemical conversion treatment.
• at least one of the first metal layer 53A and the second metal layer 53B has a corrosion-resistant film
• at least one of the first metal layer 53A and the second metal layer 53B is considered to include a corrosion-resistant film.
• the corrosion-resistant coating prevents delamination between the first metal layer 53A (e.g., aluminum alloy foil) and the outer resin layer 51 or intermediate resin layer 54 when the exterior film 50 is formed or wound, and prevents dissolution and corrosion of the surface of the first metal layer 53A (especially when the first metal layer 53A is an aluminum alloy foil, dissolution and corrosion of the aluminum oxide present in the first metal layer 53A) due to hydrogen fluoride produced by the reaction between the electrolyte and moisture.
• first metal layer 53A e.g., aluminum alloy foil
• first metal layer 53A It also improves the adhesion (wettability) of the first metal layer 53A, and prevents delamination between the first metal layer 53A and the outer resin layer 51 or intermediate resin layer 54 during welding such as heat sealing, and between the first metal layer 53A and the outer resin layer 51 or intermediate resin layer 54 during forming or winding.
• the corrosion-resistant coating prevents delamination between the second metal layer 53B (e.g., aluminum alloy foil) and the heat-sealable resin layer 56 or intermediate resin layer 54 during molding or winding of the exterior film 50, and prevents dissolution and corrosion of the surface of the second metal layer 53B due to hydrogen fluoride generated by the reaction between the electrolyte and moisture (especially when the second metal layer 53B is an aluminum alloy foil, dissolution and corrosion of aluminum oxide present in the second metal layer 53B).
• the second metal layer 53B e.g., aluminum alloy foil
• the heat-sealable resin layer 56 or intermediate resin layer 54 during molding or winding of the exterior film 50
• dissolution and corrosion of the surface of the second metal layer 53B due to hydrogen fluoride generated by the reaction between the electrolyte and moisture (especially when the second metal layer 53B is an aluminum alloy foil, dissolution and corrosion of aluminum oxide present in the second metal layer 53B).
• the second metal layer 53B improves the adhesion (wettability) of the second metal layer 53B, and shows the effect of preventing delamination between the second metal layer 53B and the heat-sealable resin layer 56 or intermediate resin layer 54 during welding such as heat sealing, and preventing delamination between the second metal layer 53B and the heat-sealable resin layer 56 or intermediate resin layer 54 during molding or winding.
• the intermediate resin layer 54 is composed of a resin composition and improves the shape conformability of the exterior film 50.
• the resin composition constituting the intermediate resin layer 54 is preferably flexible.
• resin compositions include resin compositions containing at least one of polyurethane resins, polyester resins, polybutadiene resins, acid-modified polyolefin resins, styrene elastomers, acrylic resins, silicone resins, ether resins, and ethylene copolymers.
• polyurethane resins, polyester resins, and acid-modified polyolefin resins are particularly preferred from the viewpoints of durability, adhesion, and flexibility.
• the intermediate resin layer 54 may contain additives such as fillers.
• the type of filler is not particularly limited, and examples include heat dissipating fillers, insulating fillers, and hardness enhancing fillers. Of these, heat dissipating fillers are preferred.
• the heat dissipating filler is not particularly limited as long as it has high thermal conductivity and can promote the release of heat accumulated in the resin composition. Examples of the heat dissipating filler include hexagonal boron nitride, aluminum hydroxide, and alumina.
• the content of the heat dissipating filler is preferably 5 parts by mass or more and 90 parts by mass or less, and more preferably 10 parts by mass or more and 80 parts by mass or less, when the total of the resin composition part constituting the intermediate resin layer 54 is 100 parts by mass.
• the thickness t3 of the intermediate resin layer 54 is preferably, for example, 1 to 80 ⁇ m, more preferably 2 to 60 ⁇ m, and even more preferably 5 to 40 ⁇ m.
• the thickness t3 is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, and even more preferably 5 ⁇ m or more.
• the thickness t3 is preferably 80 ⁇ m or less, more preferably 60 ⁇ m or less, and even more preferably 40 ⁇ m or less.
• the sum of the thickness t1 of the first metal layer 53A, the thickness t2 of the second metal layer 53B, and the thickness t3 of the intermediate resin layer 54 is preferably 300 ⁇ m or less, more preferably 200 ⁇ m or less, and even more preferably 150 ⁇ m or less.
• the exterior film 50 may have two or more intermediate resin layers made of different resin compositions.
• the intermediate resin layer 54A may be made of a resin composition that has higher adhesion to the first metal layer 53A
• the intermediate resin layer 54B may be made of a resin composition that has higher adhesion to the second metal layer 53B.
• the thickness t3 of the intermediate resin layer may be the sum of the thicknesses of all the intermediate resin layers.
• the second adhesive layer 55 is a layer made of an adhesive that bonds the second metal layer 53B and the heat-sealable resin layer 56.
• the adhesive used to form the second adhesive layer 55 may be the same as the adhesive used to form the first adhesive layer 52.
• the second adhesive layer 55 may be omitted.
• the heat-sealable resin layer 56 is a layer that provides the exterior film 50 with heat-sealing sealability.
• the heat-sealable resin layer 56 include resin films made of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride.
• the thickness of the heat-sealable resin layer 56 is preferably, for example, 20 to 300 ⁇ m, and more preferably 40 to 150 ⁇ m.
• the heat-sealable resin layer 56 may have two or more types of layers, each of which is made of the above resins and laminated together, as necessary.
• the exterior film 50 has one or more layers with a buffer function (hereinafter referred to as "buffer layers") outside the heat-sealable resin layer 56, and more preferably outside the first metal layer 53A.
• the outer resin layer 51 may also function as a buffer layer.
• the multiple buffer layers may be adjacent to each other or may be laminated via the outer resin layer 51, the first metal layer 53A, etc.
• the material constituting the buffer layer can be selected from any material having cushioning properties.
• the material having cushioning properties is, for example, rubber, nonwoven fabric, or foam sheet.
• the rubber is, for example, natural rubber, fluororubber, or silicone rubber.
• the rubber hardness is preferably about 20 to 90.
• the material constituting the nonwoven fabric is preferably a material having excellent heat resistance.
• the lower limit of the thickness of the buffer layer is preferably 100 ⁇ m, more preferably 200 ⁇ m, and even more preferably 1000 ⁇ m.
• the upper limit of the thickness of the buffer layer is preferably 5000 ⁇ m, and even more preferably 3000 ⁇ m.
• the preferred range of thickness of the buffer layer is 100 ⁇ m to 5000 ⁇ m, 100 ⁇ m to 3000 ⁇ m, 200 ⁇ m to 5000 ⁇ m, 200 ⁇ m to 3000 ⁇ m, 1000 ⁇ m to 5000 ⁇ m, or 1000 ⁇ m to 3000 ⁇ m.
• the most preferred range of thickness of the buffer layer is 1000 ⁇ m to 3000 ⁇ m.
• the lower limit of the buffer layer thickness is preferably 0.5 mm, and more preferably 1.0 mm.
• the upper limit of the buffer layer thickness is preferably 10 mm, and more preferably 5.0 mm, and more preferably 2.0 mm.
• the preferred ranges of the buffer layer thickness are 1.0 mm to 2.0 mm, 1.0 mm to 5.0 mm, 1.0 mm to 10 mm, 0.5 mm to 2.0 mm, 0.5 mm to 5.0 mm, and 0.5 mm to 10 mm.
• the buffer layer functions as a cushion, preventing the exterior film 50 from being damaged by impact when the energy storage device 10 is dropped or by handling during the manufacture of the energy storage device 10.
• the lid body 60 shown in FIG. 4 is, for example, rectangular and is a resin molded product made of, for example, a resin material.
• the lid body 60 may be formed, for example, by cold forming the exterior film 50, or may be a metal molded product.
• the material constituting the lid body 60 may include at least two or more types of materials selected from metal oxide, carbon material, and rubber material, and may include metal oxide, carbon material, and rubber material.
• the lid body 60 is made up of a resin material.
• "made up of a resin material” means that, when the entire material constituting the lid body 60 is taken as 100% by mass, the resin material content is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
• the material constituting the lid body 60 can contain materials other than the resin material in addition to the resin material.
• resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, as well as modified versions of these resins.
• the resin material may be a mixture of these resins, a copolymer, or a modified version of a copolymer.
• the resin material is preferably a heat-sealable resin such as polyester or polyolefin, and more preferably polyolefin.
• the lid 60 may be molded by any molding method.
• the resin material contained in the material constituting the lid 60 is preferably an olefin-based random copolymer, more preferably contains a resin containing a polyolefin skeleton as a main component, even more preferably contains polyolefin as a main component, and even more preferably contains polypropylene as a main component.
• the polyolefin may be an acid-modified polyolefin.
• the resin material contained in the material constituting the lid 60 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the lid 60 preferably contains multiple types of amide-based lubricants that further contain unsaturated fatty acid amides in addition to saturated fatty acid amides.
• the resin material contained in the material constituting the lid 60 may be a polyolefin resin to which a propylene-based elastomer having a melting point higher than 150°C has been added.
• polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters.
• copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit.
• polyethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate
• polyethylene (terephthalate/isophthalate) polyethylene (terephthalate/adipate)
• polyethylene (terephthalate/sodium sulfoisophthalate) polyethylene (terephthalate/sodium isophthalate)
• polyethylene (terephthalate/phenyl-dicarboxylate) polyethylene (terephthalate/decanedicarboxylate).
• polybutylene terephthalate is the preferred resin material from the viewpoint of increasing heat resistance and pressure resistance.
• polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene- ⁇ -olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene- ⁇ -olefin copolymers; and ethylene-butene-propylene terpolymers.
• polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. Of these, polypropylene is preferred as the resin material because of its excellent heat fusion properties and electrolyte resistance.
• the resin as the resin material may contain a filler as necessary.
• fillers include glass beads, graphite, glass fiber, and carbon fiber.
• the melt mass flow rate of the resin material contained in the material constituting the lid body 60 is preferably in the range of 1 g/10 min to 100 g/10 min, and more preferably in the range of 5 g/10 min to 80 g/10 min.
• the melt mass flow rate is measured based on JIS K7210-1:2014.
• the measurement temperature for the melt mass flow rate is 230°C.
• the lid body 60 may be configured to include a conductive material.
• “Configured to include a conductive material” means that, when the entire material constituting the lid body 60 is taken as 100% by mass, the content of the conductive material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
• the material constituting the lid body 60 can contain, in addition to the conductive material, a material other than the conductive material.
• the lid body 60 preferably has a corrosion-resistant coating as described for the first metal layer 53A and the second metal layer 53B.
• the conductive material constituting the lid body 60 is, for example, a metal material.
• the metal material constituting the lid body 60 is, for example, aluminum, an aluminum alloy, nickel, copper, or a copper alloy.
• the lid body 60 connected to the positive electrode is preferably made of aluminum or an aluminum alloy.
• the lid body 60 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy.
• the material constituting the lid body 60 connected to the negative electrode may be copper plated with nickel.
• the material constituting the lid body 60 may include recycled metal materials.
• the lid body 60 has a first surface 61, a second surface 62, and a sealing surface 63.
• the first surface 61 faces the electrode body 20.
• the second surface 62 is the surface opposite to the first surface 61.
• the sealing surface 63 is connected to the first surface 61 and the second surface 62, and is joined to the heat-sealable resin layer 56 of the exterior film 50.
• the sealing surface 63 and the heat-sealable resin layer 56 are joined by heat sealing.
• the sealing surface 63 and the exterior film 50 may be joined by any method other than heat sealing, such as welding. Specific welding methods include, for example, laser welding, ultrasonic welding, and any other method.
• the sealing surface 63 includes a first sealing surface 63A, a second sealing surface 63B, a third sealing surface 63C, and a fourth sealing surface 63D.
• the first sealing surface 63A constitutes the upper surface of the lid body 60.
• the first sealing surface 63A extends in a first direction (LR direction in this embodiment) in the energy storage device 10.
• the second sealing surface 63B and the third sealing surface 63C are connected to the first sealing surface 63A and constitute the side surface of the lid body 60.
• the second sealing surface 63B and the third sealing surface 63C extend in a second direction (UD direction in this embodiment) that intersects with the first direction in the energy storage device 10. In this embodiment, the first direction and the second direction are perpendicular to each other.
• the fourth sealing surface 63D constitutes the lower surface of the lid body 60.
• the fourth seal surface 63D extends in the first direction (the LR direction in this embodiment) in the power storage device 10.
• the lid body 60 When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is arranged on top of each other. From another perspective, when the lid body 60 is plate-shaped, it is preferable that the sealing surface 63 of the lid body 60 has a certain degree of thickness so that the sealing surface 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when forming the second sealing portion 80 described below.
• the minimum value of the thickness of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm.
• the maximum value of the thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm.
• the maximum value of the thickness of the lid body 60 may be 20 mm or more.
• the preferred ranges of thickness of the material constituting the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm.
• the material constituting the lid body 60 does not include films defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard.
• the thickness of the lid body 60 may vary depending on the part of the lid body 60. When the thickness of the lid body 60 varies depending on the part, the thickness of the lid body 60 is the thickness of the thickest part.
• the cover 60 further includes boundaries 64, 65, 66, and 67.
• Boundary 64 is the boundary between the first seal surface 63A and the second seal surface 63B.
• Boundary 65 is the boundary between the first seal surface 63A and the third seal surface 63C.
• Boundary 66 is the boundary between the fourth seal surface 63D and the second seal surface 63B.
• Boundary 67 is the boundary between the fourth seal surface 63D and the third seal surface 63C.
• the cross-sectional shape of the boundaries 64 to 67 when viewed from the FB direction may be angular, or may be rounded by applying R processing. In this embodiment, the boundaries 64 to 67 are angular.
• the main material constituting the sealing surface 63 of the lid body 60 and the resin composition constituting the heat-sealable resin layer 56 of the exterior film 50 are the same.
• the main material constituting the lid body 60 and the resin composition constituting the heat-sealable resin layer 56 are polypropylene.
• the main material refers to, for example, a material that accounts for 50% or more of the materials contained in the constituent elements.
• the lid body 60 is formed with a through hole 60X into which the electrode terminal 30 is inserted.
• the through hole 60X penetrates the first surface 61 and the second surface 62.
• the electrode terminal 30 protrudes to the outside of the exterior body 40 through the through hole 60X formed in the lid body 60.
• a small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin.
• the position at which the electrode terminal 30 protrudes to the outside can be selected arbitrarily.
• the electrode terminal 30 may protrude to the outside from a hole formed in any one of the six surfaces of the exterior body 40.
• a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin.
• the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally.
• the lid body 60 also functions as an electrode terminal, or if the electrode terminal 30 is disposed between the lid body 60 and the exterior film 50, the through hole 60X does not need to be formed in the lid body 60.
• the exterior film 50 is wrapped around the electrode body 20 to form the opening 50X, and the opposing surfaces of the exterior film 50 (the heat-sealable resin layers 56) are heat-sealed to form the first sealing portion 70.
• the first sealed portion 70 is formed by heat sealing both ends of the exterior film 50.
• the first sealed portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40.
• the position at which the first sealed portion 70 is formed in the exterior body 40 can be selected arbitrarily.
• the root 70X of the first sealed portion 70 is preferably located on the edge of the boundary between the upper surface 41 and the first side surface 43 of the exterior body 40.
• the upper surface 41 has a larger area than the first side surface 43.
• the root 70X of the first sealed portion 70 may be located on any surface of the exterior body 40.
• the first sealed portion 70 protrudes outward from the electrode body 20 in a plan view.
• the first sealed portion 70 may be folded, for example, toward the first side surface 43 of the exterior body 40, or toward the upper surface 41.
• Manufacturing method of electricity storage device 5 is a flowchart showing an example of a method for manufacturing the power storage device 10.
• the method for manufacturing the power storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, and an eighth step.
• the first step to the eighth step are performed, for example, by a manufacturing apparatus for the power storage device 10. Note that the following first step to eighth step are merely names of the steps in the method for manufacturing the power storage device 10 specified for convenience, and do not necessarily refer to the order of the steps.
• step S11 the manufacturing equipment joins each of the pair of lid bodies 60 to each of the two electrode terminals 30.
• Completion of the first process creates a pair of lid units 90 (see FIG. 6) in which the electrode terminals 30 are joined to the lid bodies 60.
• step S12 electrode body placement step
• the manufacturing device places the electrode body 20 on the heat-sealable resin layer 56 of the exterior film 50.
• the exterior film 50 may be provided with a mark for aligning the electrode body 20 in an appropriate position relative to the exterior film 50.
• the third step (lid unit arrangement step) of step S13 is performed in parallel with the second step or after the second step.
• the manufacturing apparatus arranges each of the pair of lid units 90 made in step S11 so as to face the front surface 21 and the back surface 22 of the electrode body 20, and bonds the electrode terminal 30 and the electrode body 20.
• the exterior film 50, the electrode body 20, and the pair of lid units are in a state as shown in FIG. 6.
• the exterior film 50 may be provided with a mark for properly aligning the pair of lid units 90 with respect to the exterior film 50.
• the manufacturing method of the energy storage device 10 may include, instead of the first and third steps, a step of first joining the electrode body 20 and the two electrode terminals 30, and then arranging the pair of lid bodies 60 so as to face the front surface 21 and the back surface 22 of the electrode body 20, and bonding the pair of lid bodies 60 to the pair of electrode terminals.
• the method for manufacturing the electricity storage device 10 may include arranging a pair of lid bodies 60 or a pair of lid units 90 so that they are spaced apart from each other, and then arranging the electrode body 20 between the pair of lid bodies 60 or the pair of lid units 90, so that the pair of lid bodies 60 or the pair of lid units are arranged on the front surface 21 and the back surface 22 of the electrode body 20, respectively.
• the lid unit arrangement process may be performed before the electrode body arrangement process.
• the fourth step (winding step) of step S14 is performed after the third step.
• the manufacturing device wraps the exterior film 50 around a lid unit including the electrode body 20 and a pair of lid bodies 60.
• the manufacturing device wraps the electrode body 20 and the pair of lid units 90 with the exterior film 50 so as to surround the electrode body 20 and the pair of sealing surfaces 63 from the outside while folding the exterior film 50 at a predetermined position.
• the manufacturing device winds the exterior film 50 around the electrode body 20 and the pair of lid units 90 while tension is applied to the exterior film 50, while restricting the movement of the electrode body 20 and the pair of lid units 90 with the restricting means.
• the restricting means is, for example, a groove into which the electrode body 20 and the pair of lid bodies 60 are fitted.
• the restricting means may be a device that applies an external force to the electrode body 20 and the pair of lid bodies 60 so as to prevent the electrode body 20 and the pair of lid bodies 60 from moving.
• the regulating means may be a device that applies a force to the electrode body 20 and the lid body 60 in a direction opposite to the direction in which the exterior film 50 is pulled.
• the regulating means may include a roller that runs on the exterior film 50 while the exterior film 50 is being pulled in order to remove wrinkles in the exterior film 50.
• the procedure for achieving the winding state in which the exterior film 50 is wound around the electrode body 20 and the lid unit 90 is not limited to the above winding.
• the electrode body 20 may be housed inside the exterior film 50 that has been shaped into a tube to form a pair of openings 50X, or the exterior film 50 that has been shaped into a tube and then temporarily fixed at least a portion to maintain that state, and then the lid body 60 (or the lid unit 90) may be placed in each of the pair of openings 50X, and then tension may be applied to the exterior film 50.
• the electrode body 20 and the pair of lid bodies 60 may be housed inside the exterior film 50 that has been shaped into a tube, or the exterior film 50 that has been shaped into a tube and then temporarily fixed at least a portion to maintain that state, and then tension may be applied to the exterior film 50.
• the fifth step (first sealing step) of step S15 is performed after the fourth step.
• the manufacturing equipment forms a first sealing portion (hereinafter referred to as a "temporary first sealing portion") having an unsealed portion for injecting an electrolyte solution.
• the temporary first sealing portion the heat-sealable resin layers 56 of the exterior film 50 facing each other are joined together. Note that if the power storage device 10 is, for example, an all-solid-state battery, the step of injecting an electrolyte solution is not necessary, and therefore in the fifth step, the manufacturing equipment forms the first sealing portion 70.
• the sixth step (second sealing step) of step S16 is performed after the fifth step.
• the sixth step may be performed after the fourth step, in parallel with the fifth step, or before the fifth step.
• the manufacturing device forms the second sealing portion 80 by bonding the heat-sealable resin layer 56 constituting the inner surface of the exterior film 50 to the sealing surfaces 63 of the pair of lid bodies 60 facing it.
• the bonding between the heat-sealable resin layer 56 and the sealing surfaces 63 is performed by heat sealing.
• the above bonding may also be performed by ultrasonic sealing, high-frequency sealing, or adhesion with an adhesive in addition to or instead of this.
• step S17 electrolyte injection step
• the manufacturing device injects the electrolyte through the unsealed portion formed in the temporary first sealing portion.
• the eighth step (first sealing portion forming step) of step S18 is performed after the seventh step.
• the manufacturing equipment forms the first sealing portion 70 by heat sealing a portion of the temporary first sealing portion, including the unsealed portion. Note that, if the power storage device 10 is, for example, an all-solid-state battery, the seventh and eighth steps are omitted.
• the exterior film 50 includes at least two metal layers including a first metal layer 53A and a second metal layer 53B. Thereby, even if the thickness of each of the metal layers is made smaller than the thickness of one barrier layer in a conventional exterior film, the mechanical strength of the exterior film 50 can be improved. As a result, the internal pressure resistance of the exterior film 50 is improved. In addition, by suppressing the thickness of each of the metal layers, the bending rigidity of the exterior film 50 is prevented from becoming too high. As a result, the springback can be suppressed and a winding state with an appropriate tension can be easily achieved in the manufacturing process of the electricity storage device 10. In other words, the packaging suitability of the exterior film 50 is sufficiently ensured.
• the exterior film 50 can be given the characteristics of each metal material.
• the metal material constituting the first metal layer 53A is an aluminum alloy and the metal material constituting the second metal layer 53B is stainless steel
• the first metal layer 53A mainly contributes to improving shape retention
• the second metal layer 53B mainly contributes to improving internal pressure resistance.
• the exterior film 50 includes an intermediate resin layer 54 between the first metal layer 53A and the second metal layer 53B.
• the intermediate resin layer 54 is made of a resin composition that is excellent in flexibility among resin compositions. This assists in bending the first metal layer 53A and the second metal layer 53B, and further improves the shape conformability of the exterior film 50.
• the thickness t1 of the first metal layer 53A is smaller than the thickness t2 of the second metal layer 53B.
• the value P1 obtained by multiplying the thickness t1 of the first metal layer 53A by the Young's modulus Y1 of the metal material constituting the first metal layer 53A is smaller than the value P2 obtained by multiplying the thickness t2 of the second metal layer 53B by the Young's modulus Y2 of the metal material constituting the second metal layer 53B.
• the intermediate resin layer 54 of the exterior film 50 according to the above embodiment contains a heat dissipating filler. This prevents heat from accumulating in the intermediate resin layer 54.
• the electricity storage device 10 equipped with the exterior film 50 according to the above embodiment has excellent internal pressure resistance and heat dissipation properties.
• the above-mentioned embodiments are examples of possible forms of the electricity storage device, exterior film, lid unit, and manufacturing method of the electricity storage device according to the present invention, and are not intended to limit the forms.
• the electricity storage device, exterior film, lid unit, and manufacturing method of the electricity storage device according to the present invention may take forms different from those exemplified in the embodiments.
• One example is a form in which part of the configuration of the embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to the embodiment.
• Below are some examples of modified embodiments. Note that the following modified embodiments can be combined with each other as long as there is no technical contradiction.
• the lid body 60 and the exterior film 50 may be directly welded or may be joined via an adhesive film.
• the adhesive film is not particularly limited, but for example, when the sealing surface 63 is formed of metal, a film similar to the adhesive film 31 described above is preferable.
• the adhesive film is preferably a laminated film having at least a heat-sealable resin layer, a heat-resistant base material layer, and a heat-sealable resin layer in this order.
• the specifications for the heat-sealable resin layer of the adhesive film can be the same as the specifications for the heat-sealable resin layer 56.
• the materials constituting the two heat-sealable resin layers of the adhesive film may be the same or different materials, and are appropriately selected according to the material constituting the heat-sealable resin layer 56 of the exterior film 50 and the material constituting the sealing surface 63.
• the material constituting the heat-sealable resin layer of the adhesive film that is bonded to the sealing surface 63 is preferably an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. It is preferable that the heat-sealing resin layer of the adhesive film on the side that is bonded to the exterior film 50 is made of the same material as the material that constitutes the heat-sealing resin layer 56 of the exterior film 50.
• the heat-resistant substrate layer may be any film made of a heat-resistant resin, such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, or other unstretched or stretched films.
• a heat-resistant resin such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, or other unstretched or stretched films.
• Polyethylene terephthalate is particularly preferred, as it is inexpensive and has high strength.
• the exterior film 50 of the power storage device 10 may extend outward beyond at least one of the two lid bodies 60 in the FB direction.
• the electrode body 20 is sealed by closing the portion of the exterior film 50 that extends outward beyond the lid body 60.
• the portion of the exterior film 50 that extends beyond the lid body 60 may be folded inward so that the outer surfaces of the exterior film 50 come into contact with each other, as in a Gabeltop container, or may be folded toward any surface of the exterior body 40, as in a brick container.
• the energy storage device 10 may not have one of the pair of lid bodies 60 or the pair of lid units 90.
• the electrode body 20 in the FB direction, in the portion of the exterior body 40 where the lid body 60 or the lid unit 90 is omitted, the electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the electrode body 20.
• the portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Gabeltop container or a brick container. In other words, it is sufficient that the exterior film 50 wraps around the electrode body 20 so as to form at least one opening 50X.
• the outer shape of the exterior body 40 can be changed as desired.
• the outer shape of the exterior body 40 may be a cylinder, a prism, or a cube.
• the electrode body 20 may be formed in a roughly cylindrical shape
• the lid body 60 may be formed in a disk shape.
• the lid 60 may be a member formed by integrating separate members by injection molding, welding, or the like.
• the portion including the sealing surface 63 and the portion near the center surrounded by the sealing surface 63 may each be made of a member formed of a different material, and these members may be integrated by injection molding or via a heat-weldable resin film, etc.
• Electrode body 30 Electrode terminal 40: Exterior body 50: Exterior film 51: Outer resin layer 53A: First metal layer 53B: Second metal layer 54: Intermediate resin layer 60: Lid body 61: First surface 62: Second surface 63: Sealing surface 90: Lid unit 511: First surface

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