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
  • H01G11/14—Arrangements or processes for adjusting or protecting hybrid or EDL capacitors
  • H01G11/20—Reformation or processes for removal of impurities, e.g. scavenging
• • 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
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/52—Removing gases inside the secondary cell, e.g. by absorption
• • 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
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
  • H01M50/474—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by their position inside the cells
• • 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
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
  • H01M50/48—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by the material
  • H01M50/483—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
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
  • H01M50/48—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by the material
  • H01M50/486—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
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• • 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

• This disclosure relates to a resin film for an electricity storage device and an electricity storage device.
• the exterior housing is an essential component for sealing the electricity storage device elements, such as the electrodes and electrolyte.
• metal exterior housings have been widely used as exterior housings for electricity storage devices.
• the electricity storage device element is generally sealed with a packaging body formed by heat-sealing the heat-sealable resin layer around the periphery of the outer casing for an electricity storage device, thereby obtaining an electricity storage device in which the electricity storage device element is housed inside the outer casing for an electricity storage device.
• a barrier layer made of, for example, metal foil.
• the heat-sealable resin layer of the exterior body absorbs water before the electricity storage device element is sealed in the exterior body, there is a risk that the moisture in the heat-sealable resin layer will penetrate into the electricity storage device element after the electricity storage device element is sealed.
• the performance of lithium ion secondary batteries, all-solid-state batteries, and the like deteriorates when moisture penetrates into the power storage device through the sealing portion of the exterior body.
• the electrolyte e.g., LiPF6
• HF hydrogen fluoride
• sulfur in the solid electrolyte reacts with moisture to generate H2S (hydrogen sulfide).
• H2S hydrogen sulfide
• the inventors of the present disclosure have investigated absorbing moisture by disposing a gas absorbent between the exterior body and the electricity storage device element in a package obtained by heat-sealing heat-sealable resin layers at the peripheral edge of the exterior body for an electricity storage device. This is because they believed that the gas absorbent disposed between the exterior body and the electricity storage device element could absorb water vapor that penetrates from outside the package. It is also expected that the gas absorbent would absorb H2S gas generated in the all-solid-state battery.
• all-solid-state batteries for example, a non-fluid solid electrolyte is used in the energy storage device element. Therefore, when the energy storage device element is vacuum-sealed in a package formed from the energy storage device exterior, the energy storage device exterior conforms to the shape of the solid electrolyte, making it easy for wrinkles and dents to form in the energy storage device exterior. These wrinkles and dents can lead to pinholes and cracks in the exterior's barrier layer when the all-solid-state battery expands and contracts, potentially hindering long-term use of the all-solid-state battery.
• the primary objective of this disclosure is to provide a resin film for an electricity storage device that can effectively absorb gas inside the electricity storage device and that can also suppress the occurrence of wrinkles, dents, etc. in the exterior body for the electricity storage device when the electricity storage device elements are vacuum-sealed.
• the inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. As a result, they discovered that by disposing a resin film for an electricity storage device that contains a gas absorbent and a porous resin layer between the exterior body of the electricity storage device and the electricity storage device element, gas can be suitably absorbed inside the electricity storage device. More specifically, they discovered that even when the electricity storage device element is vacuum-sealed in a package formed from the exterior body for the electricity storage device, by disposing the resin film for an electricity storage device between the exterior body of the electricity storage device and the electricity storage device element, gas can be suitably absorbed inside the electricity storage device.
• a resin film for an electricity storage device that is disposed between an exterior body of an electricity storage device and an electricity storage device element,
• the resin film for an electricity storage device contains a gas absorbent and a porous resin layer.
• a resin film for an electricity storage device that can effectively absorb gas inside the electricity storage device and that can also suppress the occurrence of wrinkles, dents, etc. in the exterior body for the electricity storage device when the electricity storage device elements are vacuum-sealed. Furthermore, according to the present disclosure, it is also possible to provide an electricity storage device that utilizes this resin film for an electricity storage device.
• 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of a resin film for an electricity storage device according to the present disclosure.
• FIG. 2 is a schematic diagram illustrating a method for preparing a measurement sample for evaluating moisture permeability in the examples.
• 1 is a schematic diagram showing an example of a cross-sectional structure of an outer casing for an electricity storage device according to the present disclosure.
• 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• FIG. 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• 1 is a schematic diagram illustrating an example of a cross-sectional structure of an electricity storage device according to the present disclosure.
• FIG. 1 is a schematic diagram for explaining evaluation of wrinkles and dents in an exterior body (exterior material) during vacuum sealing in Examples.
• Resin film for an electricity storage device The resin film for an electricity storage device of the present disclosure is disposed between the exterior body of an electricity storage device and an electricity storage device element.
• the resin film for an electricity storage device of the present disclosure contains a gas absorbent and a porous resin layer. As shown in the schematic diagrams of Figures 9 to 13 , the resin film for an electricity storage device 1 of the present disclosure is disposed between the exterior body 3 of an electricity storage device and an electricity storage device element 4.
• a barrier layer made of, for example, metal foil
• the heat-sealable resin layer of the exterior body is heat-sealed to seal the electricity storage device element, the end faces of the heat-sealable resin layer are exposed to the outside, and there is a risk of moisture penetrating from the end faces of the heat-sealable resin layer.
• the heat-sealable resin layer of the exterior body absorbs water before the electricity storage device element is sealed with the exterior body, there is a risk that the moisture in the heat-sealable resin layer will penetrate into the electricity storage device element after it has been sealed.
• the resin film 1 for an electricity storage device of the present disclosure is disposed between the exterior body 3 of the electricity storage device 10 and the electricity storage device element 4 (i.e., inside the exterior body 3 of the electricity storage device 10), it is possible to effectively prevent moisture from penetrating from the edge of the heat-sealable resin layer of the exterior body and from penetrating from moisture contained in the heat-sealable resin layer of the exterior body.
• the resin film 1 for an electricity storage device of the present disclosure contains a water absorbent, it can absorb and retain moisture that has penetrated from the heat-sealable resin layer of the exterior body, thereby preventing moisture from reaching the electricity storage device element 4.
• the inventors of the present disclosure conducted further research and found that when an electricity storage device element is vacuum-sealed in a package formed from an exterior body for an electricity storage device (hereinafter sometimes simply referred to as an exterior body), the gas absorption effect of the gas absorbent may not be fully exerted.
• the resin film 1 for an electricity storage device of the present disclosure includes a porous resin layer, and therefore maintains a space inside the exterior body 3 of the electricity storage device 10 through which gas can move. Therefore, the gas absorbent included in the resin film 1 for an electricity storage device can suitably absorb gas inside the exterior body 3 of the electricity storage device 10.
• the electricity storage device resin film 1 of the present disclosure has excellent conformability because it includes a porous resin layer.
• the electricity storage device resin film 1 of the present disclosure can suitably fill gaps formed between the electricity storage device exterior and the electricity storage device element, thereby suppressing the occurrence of wrinkles, dents, etc. in the electricity storage device exterior when the electricity storage device element is vacuum-sealed.
• moisture refers to gaseous and/or liquid moisture.
• the resin film for an electricity storage device of the present disclosure can also absorb sulfur-based gases.
• sulfur-based gases include hydrogen sulfide, dimethyl sulfide, methyl mercaptan, and sulfur oxides represented by SOx.
• moisture to be absorbed When absorbed by, for example, a solid electrolyte-type lithium-ion battery, moisture to be absorbed generates various outgases, and sulfur-based gases are components of these outgases (generated, for example, when the electricity storage device is an all-solid-state battery using a sulfide-based inorganic solid electrolyte or a lithium secondary battery using lithium-sulfur in the positive electrode).
• the energy storage device 10 has a structure in which an energy storage device element 4 is sealed with an exterior body 3.
• the exterior body 3 may be composed of an exterior material (laminated film) made of a laminate having at least a base layer 31, a barrier layer 33, and a heat-sealable resin layer 35 in this order, or may be composed of the exterior material and a lid. That is, the exterior material and the lid constitute an exterior body (exterior body for an energy storage device) that seals the energy storage device element.
• the metal terminals 2 protrude outside the exterior body 3.
• the metal terminals 2 are connected to the positive and negative electrodes of the energy storage device element 4.
• An adhesive film 21 for metal terminals is disposed between the metal terminals 2 and the exterior body 3, enhancing adhesion between the metal terminals 2 and the heat-sealable resin layer 35 of the exterior body.
• the electricity storage device 10 is sealed by covering the electricity storage device element 4 with the exterior body 3 so that a flange portion (peripheral portion 3a of the exterior body 3) of the exterior body 3 can be formed around the periphery of the electricity storage device element 4, and then heat-sealing the flange portion of the exterior body 3 to seal the electricity storage device element 4.
• the exterior body 3 is used so that the heat-fusible resin layer 35 faces inside (the surface in contact with the electricity storage device element 4).
• the position where the resin film for an electricity storage device 1 of the present disclosure is applied to the electricity storage device 10 is not particularly limited, as long as it is between the exterior body 3 and the electricity storage device element 4.
• it may be positioned on a portion of the surface on the electricity storage device element 4 side (the heat-sealable resin layer 35 side), or as shown in Figures 11 to 13, in the electricity storage device 10, the resin film for an electricity storage device 1 may be positioned on the entire surface of the exterior body 3 on the electricity storage device element 4 side (the heat-sealable resin layer 35 side).
• the resin film 1 for an electricity storage device may be disposed only between the exterior body 3 and the electricity storage device element 4.
• This type of arrangement is expected to make it less likely for wrinkles, dents, etc. to form in the exterior body 3 over a wide area during vacuum sealing, and also to have the effect of uniforming pressure when restraining the electricity storage device 10 from the outside when the device is an all-solid-state battery.
• Another advantage is that the area of the resin film 1 for an electricity storage device disposed within the electricity storage device 10 is large, which also increases the gas absorption effect.
• FIG. 10 it may be disposed between the peripheral edge 3a (heat-sealed portion) of the exterior body 3 and the electricity storage device element 4. Since gaps are likely to occur between the exterior body 3 and the metal terminal 2 in the electricity storage device 10 after vacuum sealing, by disposing the electricity storage device resin film 1 as shown in FIG. 10, this gap can be suitably filled, and the occurrence of wrinkles, dents, etc. in the exterior body when the electricity storage device element is vacuum-sealed can be suitably suppressed. In this case, the electricity storage device resin film 1 is disposed so as to be in contact with the exterior body 3, the metal terminal 2, and the electricity storage device element 4.
• the electricity storage device element 4 may be covered with the electricity storage device resin film 1, or as shown in FIG. 12, a portion of the surface of the metal terminal 2 may also be covered with the electricity storage device resin film 1.
• the electricity storage device resin film 1 of the present disclosure may be disposed between the exterior body 3 of the electricity storage device 10 and the electricity storage device element 4 so that the electricity storage device element 4 is sealed by the electricity storage device resin film 1.
• the electricity storage device resin film 1 may also be present between the exterior body 3 and the metal terminal 2 and heat-sealed. In these arrangements, the porous resin layer of the electricity storage device resin film 1 can be expected to protect the electricity storage device element 4 from external impacts.
• the resin film 1 for an electricity storage device When the resin film 1 for an electricity storage device is located in the flange portion of the exterior body 3 (peripheral edge portion 3a of the exterior body 3), it is preferable that the resin film 1 for an electricity storage device have heat-sealing properties.
• the resin film 1 for an electricity storage device is located in the flange portion where the exterior body 3 is heat-sealed, so it is preferable that the resin film 1 for an electricity storage device have heat-sealing properties with the heat-sealable resin layer 35 and the adhesive film 21 for the metal terminal. It is also preferable that the resin films 1 for an electricity storage device have heat-sealing properties with each other.
• a resin film 1 for an electricity storage device is also suitable to place a resin film 1 for an electricity storage device at the formed corners of the exterior body 3 of the electricity storage device 10. Spaces are likely to form between the exterior body 3 and the electricity storage device element 4 at the formed corners of the exterior body 3, and wrinkles, dents, etc. are likely to occur during vacuum sealing. By filling this space with the resin film 1 for an electricity storage device, wrinkles, dents, etc. can be suppressed during vacuum sealing.
• a resin film for an electricity storage device 1 at the connection between the electricity storage device element 4 and the metal terminal 2 in the electricity storage device 10. This arrangement is expected to have the effect of protecting the connection between the electricity storage device element 4 and the metal terminal 2 with the resin film for an electricity storage device 1.
• the resin film 1 for an electricity storage device can also be folded or otherwise shaped and placed inside the electricity storage device 10.
• the positive and negative electrodes may differ in size when viewed in plan. In such cases, the difference in size between the positive and negative electrodes creates a space, making the electrodes more susceptible to damage. By placing the resin film 1 for an electricity storage device in this space, it is possible to prevent damage to the electrodes.
• the resin film 1 for an electricity storage device of the present disclosure can be placed in various positions between the exterior body 3 and the electricity storage device element 4, taking into consideration its gas absorption effect inside the electricity storage device, its effect of suppressing wrinkles, dents, etc. in the exterior body when the electricity storage device element is vacuum-sealed, and its effect of protecting the components that make up the electricity storage device 10, such as the electricity storage device element 4.
• the resin film for an electricity storage device includes at least a porous resin layer.
• the porous resin layer serves as a gas absorbing layer containing a gas absorbent.
• the resin film for an electricity storage device may include, in addition to the porous resin layer, a gas absorbing layer that is not a porous resin layer.
• Examples of the configuration of the resin film for an electricity storage device of the present disclosure include a single-layer configuration of a porous resin layer (the porous resin layer serves as the gas absorption layer), a two-layer configuration in which a porous resin layer and a gas absorption layer are laminated together, a three-layer configuration in which a porous resin layer, a gas absorption layer, and a porous resin layer are laminated together in this order, a three-layer configuration in which a porous resin layer, an adhesive layer, and a gas absorption layer are laminated together in this order, a five-layer configuration in which a porous resin layer, an adhesive layer, a gas absorption layer, an adhesive layer, and a porous resin layer are laminated together in this order, and a three-layer configuration in which a gas absorption layer, a porous resin layer, and a gas absorption layer are laminated together in this order.
• the resin film for an electricity storage device may have a single-layer configuration or a multi-layer configuration.
• the layers may or may not be bonded together.
• the porous resin layer and the gas absorbing layer may not be bonded together, but may be independent sheets stacked one on top of the other. Even in this case, the porous resin layer and the gas absorbing layer are in contact with each other.
• they may be bonded together using an adhesive layer or adhesive tape, or they may be bonded by heat fusion without using an adhesive layer or adhesive tape.
• FIGS 1 to 6 Examples of the layer structure of a resin film for an electricity storage device are shown in Figures 1 to 6 (each of which is a schematic diagram showing an example of the cross-sectional structure of a resin film for an electricity storage device).
• the resin film for an electricity storage device 1 may be composed of only a porous resin layer 11.
• the resin film may also have a gas absorbing layer 12, an adhesive layer 13, etc.
• FIG. 2 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a laminate composed of two layers: a porous resin layer 11 and a gas absorbing layer 12.
• FIG. 3 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a three-layer laminate composed of a gas absorbing layer 12, a porous resin layer 11, and a gas absorbing layer 12 laminated in this order.
• FIG. 4 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a three-layer laminate composed of a porous resin layer 11, a gas absorbing layer 12, and a porous resin layer 11 laminated in this order.
• FIG. 3 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a three-layer laminate composed of a gas absorbing layer 12, a porous resin layer 11, and a gas absorbing layer 12 laminated in this order.
• FIG. 4 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a three-layer laminate composed of a
• FIG. 5 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a three-layer laminate composed of a porous resin layer 11, an adhesive layer 13, and a gas absorbing layer 12 laminated in this order.
• FIG. 6 illustrates a laminate structure in which the resin film for an electricity storage device 1 is a five-layer laminate composed of a porous resin layer 11, an adhesive layer 13, a gas absorbing layer 12, an adhesive layer 13, and a porous resin layer 11 laminated in this order.
• the thickness ratio of the porous resin layer 11 to the gas absorbing layer 12 is preferably about 100:1 to 1:1, more preferably about 50:1 to 2:1, and even more preferably about 20:1 to 5:1. Note that when there are two or more porous resin layers 11 and two or more gas absorbing layers 12, the thickness ratio is the ratio of the total thickness of the porous resin layers 11 and the gas absorbing layers 12.
• the overall thickness of the resin film 1 for an electricity storage device is preferably at least about 20 ⁇ m, more preferably at least about 30 ⁇ m, and even more preferably at least about 50 ⁇ m. It is also preferably no more than about 3000 ⁇ m, more preferably no more than about 2000 ⁇ m, and even more preferably no more than about 1200 ⁇ m. Preferred ranges include approximately 20 to 3000 ⁇ m, approximately 20 to 2000 ⁇ m, approximately 20 to 1200 ⁇ m, approximately 30 to 3000 ⁇ m, approximately 30 to 2000 ⁇ m, approximately 30 to 1200 ⁇ m, approximately 50 to 3000 ⁇ m, approximately 50 to 2000 ⁇ m, and approximately 50 to 1200 ⁇ m.
• the resin film 1 for an electricity storage device has heat-sealing properties.
• the resin film 1 for an electricity storage device is located in the flange portion (peripheral portion 3a of the exterior body 3) of the exterior body 3, it is preferable to increase the heat-sealing properties of the resin film 1 for an electricity storage device. Therefore, for example, when the resin film 1 for an electricity storage device is composed of three or more layers, it is preferable that the layer located on the surface contains a heat-sealing resin. Furthermore, from the viewpoint of preventing a decrease in the heat-sealing properties of the layer located on the surface, it is preferable that the layer located on the surface does not contain a gas-absorbing agent.
• the gas absorbing layer 12 is provided between the layers located on the surface. This is because if the gas absorbing layer 12 is located on the surface, it will absorb moisture from the atmosphere before the electricity storage device is manufactured, and the water absorption performance of the gas absorbing layer 12 is likely to decrease. Furthermore, in an electricity storage device, it is also preferable that the layer located on the exterior body 3 side is the gas absorbing layer 12. This is because the layer located on the exterior body 3 side is close to the exterior body 3 and is therefore more likely to absorb moisture that has infiltrated from the exterior body 3 side.
• the gas absorbing layer 12 be the layer located on the electricity storage device element 4 side. This is because the layer located on the electricity storage device element 4 side is close to the electricity storage device element 4 and is more likely to absorb moisture contained in the electricity storage device element 4.
• the resin contained in the resin film 1 for an electrical storage device is not particularly limited as long as it does not impair the effects of the present disclosure.
• a thermoplastic resin is preferable, and a heat-sealable resin is more preferable.
• resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins.
• the resin forming the resin film 1 for an electrical storage device may also be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins.
• heat-sealable resins such as polyester and polyolefin are preferred.
• polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters.
• Copolymer polyesters include those primarily composed of ethylene terephthalate repeating units.
• polyesters in which ethylene terephthalate repeating units are polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl dicarboxylate), and polyethylene (terephthalate/decane dicarboxylate).
• polyethylene (terephthalate/isophthalate) polyethylene (terephthalate/adipate)
• polyethylene (terephthalate/sodium sulfoisophthalate) polyethylene (terephthalate/sodium isophthalate)
• polyethylene (terephthalate/phenyl dicarboxylate) polyethylene (terephthalate/decane dicarboxylate).
• polybutylene terephthalate is particularly preferred from the viewpoint of improving heat
• 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.
• 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 copoly
• polystyrene resin When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more. Of these, polypropylene is particularly preferred due to its excellent heat-sealing properties.
• the resin contained in the resin film for an electrical storage device 1 may contain an elastomer.
• the elastomer serves to enhance the flexibility of the resin film for an electrical storage device 1 while ensuring its durability in high-temperature environments.
• Preferred elastomers include at least one thermoplastic elastomer selected from polyesters, polyamides, polyurethanes, polyolefins, polystyrenes, and polyethers, as well as thermoplastic elastomer copolymers thereof.
• the elastomer content in the resin film for an electrical storage device 1 is not particularly limited, as long as it is sufficient to enhance the flexibility of the resin film for an electrical storage device 1 while ensuring its durability in high-temperature environments.
• the content may be approximately 0.1% by mass or more, preferably approximately 0.5% by mass or more, more preferably approximately 1.0% by mass or more, and even more preferably approximately 3.0% by mass or more.
• the content may also be, for example, approximately 10.0% by mass or less, approximately 8.0% by mass or less, or approximately 5.0% by mass or less.
• Preferred ranges for the content include approximately 0.1 to 10.0% by mass, approximately 0.1 to 8.0% by mass, approximately 0.1 to 5.0% by mass, approximately 0.5 to 10.0% by mass, approximately 0.5 to 8.0% by mass, approximately 0.5 to 5.0% by mass, approximately 1.0 to 10.0% by mass, approximately 1.0 to 8.0% by mass, approximately 1.0 to 5.0% by mass, approximately 3.0 to 10.0% by mass, approximately 3.0 to 8.0% by mass, and approximately 3.0 to 5.0% by mass.
• the resin content of the resin film 1 for an electrical storage device is, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.
• the upper limit is, for example, 99% by mass or less. Preferred ranges include approximately 40 to 99% by mass, approximately 50 to 99% by mass, approximately 60 to 99% by mass, and approximately 70 to 99% by mass.
• the resin film 1 for an electricity storage device can contain various plastic compounding agents and additives, for example, to improve or modify processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mildew resistance, electrical properties, strength, etc.
• the content can range from trace amounts to several tens of percent, and can be any amount depending on the purpose.
• Common additives that can be included include, for example, antiblocking agents, lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, modifying resins, etc.
• the porous resin layer 11 is a layer provided primarily to ensure a path for the resin film for an electricity storage device 1 in the package formed by the exterior body 3 to absorb gas (moisture, sulfur-based gas, etc.). Specifically, assuming a case in which an electricity storage device element is vacuum-sealed in a package formed by the exterior body, the presence of the porous resin layer ensures a path for gas permeation in the package, and the gas absorbent contained in the resin film for an electricity storage device can suitably absorb the gas in the package.
• gas moisture, sulfur-based gas, etc.
• the resin constituting the porous resin layer does not need to be gas permeable as long as a gas permeation path due to the porous structure is ensured, but it is preferable that the resin be gas permeable. Furthermore, it is also preferable that the porous resin layer include communicating holes that communicate from one side of the layer to the other side.
• the porous resin layer 11 contained in the resin film for an electricity storage device 1 may be a single layer or two or more layers.
• the porous resin layer can be formed from a resin.
• porous resins that can be used include well-known resin foams and fibers, with foams being preferred. Porous resins are readily available commercially.
• examples of the foaming agent used to foam the resin include organic and inorganic foaming agents.
• organic foaming agents include azo foaming agents such as azodicarbonamide (ADCA), azobisformamide, and azobisisobutyronitrile; fluorinated alkane foaming agents such as trichloromonofluoromethane; hydrazine foaming agents such as paratoluenesulfonylhydrazide; semicarbazide foaming agents such as p-toluenesulfonylsemicarbazide; triazole foaming agents such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso foaming agents such as N,N-dinitrosoterephthalamide.
• azo foaming agents such as azodicarbonamide (ADCA), azobisformamide, and azobisisobutyronitrile
• fluorinated alkane foaming agents such as trichloromonofluo
• inorganic foaming agents examples include ammonium carbonate, ammonium bicarbonate, ammonium nitrite, ammonium borohydride, and azides.
• Microcapsule-type foaming agents may also be used.
• Microcapsule-type blowing agents preferably have a core made of a thermal expansion agent such as a hydrocarbon, and a shell made of a resin such as an acrylonitrile copolymer.
• the foam has foam cells inside.
• the foam cells may be a mixture of open and closed cells. Open cells are preferred.
• the number, size, density, shape, etc. of the foam cells are not particularly limited and can be designed appropriately depending on the required performance of the resin film for an electricity storage device of the present invention.
• the foam cells can be formed by foaming the foaming agent contained in the foaming-agent-containing resin composition used to form the foam.
• the porous resin layer 11 may be made up of only one type of resin, or two or more types.
• Examples of the resin that makes up the porous resin layer 11 include thermoplastic resins and curable resins.
• thermoplastic resins include polyolefin, polyester, polyamide, and acrylic resin.
• the porous resin layer 11 may be made of only one type of thermoplastic resin, or two or more types.
• thermoplastic resins polyolefins, polyesters, etc. are preferred as the resin that constitutes the porous resin layer 11.
• 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.
• 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 copoly
• the polyolefin resin when it is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more. Of these, polyethylene and polypropylene are particularly preferred due to their excellent heat-sealing properties.
• 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.
• polyesters in which ethylene terephthalate is the main repeating unit polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl dicarboxylate), and polyethylene (terephthalate/decane dicarboxylate). These polyesters may be used alone or in combination of two or more.
• Curable resin refers to a resin that has curability, such as a thermosetting resin or an ionizing radiation curable resin, and is, for example, one that does not have a clear melting peak temperature after curing.
• curable resins include urethane resin and epoxy resin.
• the porous resin layer 11 may be made up of only one type of curable resin, or two or more types.
• the total thickness of the porous resin layer 11 is preferably at least about 20 ⁇ m, more preferably at least about 100 ⁇ m, and even more preferably at least about 200 ⁇ m. It is also preferably no greater than about 3000 ⁇ m, more preferably no greater than about 2000 ⁇ m, and even more preferably no greater than about 1000 ⁇ m.
• Preferred ranges include approximately 20 to 3000 ⁇ m, approximately 20 to 2000 ⁇ m, approximately 20 to 1000 ⁇ m, approximately 100 to 3000 ⁇ m, approximately 100 to 2000 ⁇ m, approximately 100 to 1000 ⁇ m, approximately 100 to 3000 ⁇ m, approximately 100 to 2000 ⁇ m, approximately 100 to 1000 ⁇ m, approximately 100 to 3000 ⁇ m, approximately 100 to 2000 ⁇ m, approximately 100 to 1000 ⁇ m, approximately 100 to 3000 ⁇ m, approximately 100 to 2000 ⁇ m, and approximately 100 to 1000 ⁇ m.
• the thickness of each porous resin layer 11 is not particularly limited as long as it is sufficient to ensure a gas permeation path in the vacuum-sealed package. From the viewpoint of optimally achieving the effects of the present disclosure, the thickness is preferably at least about 20 ⁇ m, more preferably at least about 100 ⁇ m, and even more preferably at least about 200 ⁇ m. Also, the thickness is preferably no more than about 3000 ⁇ m, more preferably no more than about 2000 ⁇ m, and even more preferably no more than about 1000 ⁇ m.
• Preferred ranges include approximately 20 to 3000 ⁇ m, approximately 20 to 2000 ⁇ m, approximately 20 to 1000 ⁇ m, approximately 100 to 3000 ⁇ m, approximately 100 to 2000 ⁇ m, approximately 100 to 1000 ⁇ m, approximately 200 to 3000 ⁇ m, approximately 200 to 2000 ⁇ m, and approximately 200 to 1000 ⁇ m.
• the density of the porous resin layer 11 is not particularly limited as long as it can ensure a gas permeation path in the vacuum-sealed package. From the viewpoint of suitably exerting the effects of the present disclosure, the density is preferably about 0.01 g/cm or more , more preferably about 0.02 g/cm or more , even more preferably about 0.2 g/cm or more, even more preferably about 0.3 g/cm or more, and even more preferably about 0.4 g/cm or more .
• the density is also preferably about 2.0 g/cm or less , more preferably about 1.5 g/cm or less, even more preferably about 1.3 g/cm or less, and even more preferably 1.0 g/cm or less.
• Preferred ranges include about 0.01 to 2.0 g/cm, about 0.01 to 1.5 g/cm, about 0.01 to 1.3 g/cm, about 0.01 to 1.0 g /cm, and 0.02 to 2.0 g/cm. 3 , about 0.02 to 1.5 g/ cm3 , about 0.02 to 1.3 g/ cm3 , about 0.02 to 1.0 g/ cm3 , about 0.2 to 2.0 g/ cm3 , about 0.2 to 1.5 g/ cm3 , about 0.2 to 1.3 g/ cm3 , about 0.2 to 1.0 g/ cm3 , about 0.3 to 2.0 g/ cm3 , about 0.3 to 1.5 g/ cm3 , about 0.3 to 1.3 g/ cm3 , about 0.3 to 1.0 g/ cm3 , about 0.4 to 2.0 g/ cm3 , about 0.4 to 1.5 g/cm3, about 0.4 to 1.3 g/ cm3 , and about 0.4 to 1.0 g/ cm3 .
• the gas absorbing layer 12 is a layer containing a gas absorbent. Any layer containing a gas absorbent can be called a gas absorbing layer 12.
• the porous resin layer 11 described above contains a gas absorbent
• the porous resin layer 11 also functions as the gas absorbing layer 12.
• the porous resin layer 11 may or may not contain a gas absorbent.
• the gas absorbing layer 12 contained in the resin film for an electricity storage device 1 may be a single layer or two or more layers.
• gases that are absorbed by gas absorbents include moisture and sulfur-based gases.
• water absorbing agents, sulfur-based gas absorbents, and the like are used as gas absorbents.
• moisture that is absorbed by water absorbing agents is gaseous and/or liquid moisture.
• sulfur-based gases that are absorbed by sulfur-based gas absorbents include hydrogen sulfide, dimethyl sulfide, methyl mercaptan, and sulfur oxides represented by SOx.
• the moisture that is absorbed When absorbed by, for example, a solid electrolyte-type lithium-ion battery, the moisture that is absorbed generates various outgases, and sulfur-based gases are components of these outgases (for example, generated when the power storage device is an all-solid-state battery using a sulfide-based inorganic solid electrolyte or a lithium secondary battery using lithium-sulfur in the positive electrode).
• the water-absorbing agent contained in the resin film 1 for an electricity storage device is not particularly limited as long as it exhibits water absorption when dispersed in the resin film.
• inorganic water-absorbing agents can be suitably used from the viewpoint of temporal stability in an electricity storage device.
• preferred inorganic water-absorbing agents include calcium oxide (which becomes calcium hydroxide upon absorbing water), magnesium sulfate, magnesium oxide (which becomes magnesium hydroxide upon absorbing water), calcium chloride, zeolite, aluminum oxide, silica gel, alumina gel, and burnt alum.
• inorganic chemical water-absorbing agents generally have a higher water-absorbing effect than inorganic physical water-absorbing agents, can be reduced in content, and easily achieve sufficient water absorption and heat-sealing properties in a single layer.
• inorganic chemical water-absorbing agents calcium oxide, magnesium sulfate, and magnesium oxide are particularly preferred because they exhibit low moisture re-release, high temporal stability in low-humidity conditions within the package, and an absolute dry effect.
• the bone-drying effect refers to the effect of absorbing water until the relative humidity reaches approximately 0%
• the humidity-regulating effect refers to the effect of absorbing water when the humidity is high and releasing moisture when the humidity is low, thereby maintaining a constant humidity.
• an inorganic chemical absorbent when used in a high-temperature environment, such as for an all-solid-state battery, an inorganic chemical absorbent with a high temperature range for re-releasing moisture is preferred.
• the content of the water absorbing agent contained in the gas absorbing layer 12 of the resin film 1 for an electrical storage device is not particularly limited as long as the effects of the present disclosure are achieved. It is preferably at least about 0.5 parts by mass, more preferably at least about 2 parts by mass, and even more preferably at least about 3 parts by mass, relative to 100 parts by mass of the resin contained in the gas absorbing layer 12. It is also preferably at most about 50 parts by mass, more preferably at most about 45 parts by mass, and even more preferably at most 40 parts by mass.
• Preferred ranges for the content include approximately 0.5 to 50 parts by mass, 0.5 to 45 parts by mass, 0.5 to 40 parts by mass, 2 to 50 parts by mass, 2 to 45 parts by mass, 2 to 40 parts by mass, 3 to 50 parts by mass, 3 to 45 parts by mass, and 3 to 40 parts by mass.
• the content of the water absorbing agent contained in the entire resin film 1 for an electricity storage device is not particularly limited as long as the effects of the present disclosure are achieved, and is preferably about 0.5 parts by mass or more, more preferably about 2 parts by mass or more, even more preferably about 3 parts by mass or more, relative to 100 parts by mass of the resin contained in the resin film 1 for an electricity storage device.
• the content is also preferably about 50 parts by mass or less, more preferably about 45 parts by mass or less, and even more preferably 40 parts by mass or less.
• Preferred ranges for the content include about 0.5 to 50 parts by mass, about 0.5 to 45 parts by mass, about 0.5 to 40 parts by mass, about 2 to 50 parts by mass, about 2 to 45 parts by mass, about 2 to 40 parts by mass, about 3 to 50 parts by mass, about 3 to 45 parts by mass, and about 3 to 40 parts by mass.
• the water-absorbing agent contained in the gas absorbing layer 12 is preferably contained via a masterbatch obtained by melt-blending the water-absorbing agent with a resin, for example, from the standpoint of improving the dispersibility of the water-absorbing agent in the film (suppressing the formation of aggregates (fisheyes)) and adding it at a high concentration.
• a masterbatch is prepared by melt-blending the water-absorbing agent with a resin at a relatively high concentration.
• the obtained masterbatch is further mixed with a resin and formed into a film, thereby forming the gas absorbing layer 12.
• the content of the water-absorbing agent in the masterbatch is preferably approximately 20 to 90% by mass, and more preferably approximately 30 to 70% by mass. Within the above range, it is easy to incorporate a necessary and sufficient amount of water-absorbing agent in a dispersed state into the gas absorbing layer 12.
• the number average particle size of the water-absorbing agent is preferably approximately 30 ⁇ m or less, more preferably approximately 15 ⁇ m or less, and preferably approximately 0.1 ⁇ m or more, with preferred ranges being approximately 0.1 to 30 ⁇ m and approximately 0.1 to 15 ⁇ m.
• the sulfur-based gas absorbent preferably contains a sulfur-based gas physical absorbent and/or a sulfur-based gas chemical absorbent.
• a sulfur-based gas physical absorbent in combination with a sulfur-based gas chemical absorbent, it becomes possible to easily absorb a variety of sulfur-based gases.
• the sulfur-based gas absorbent is used, for example, in powder form.
• the maximum particle size of the sulfur-based gas absorbent is preferably 20 ⁇ m or less, and the number average particle size of the powder is preferably 0.1 ⁇ m or more and 15 ⁇ m or less. If the number average particle size is smaller than the above range, the sulfur-based gas absorbent is likely to aggregate. If the number average particle size is larger than the above range, the homogeneity of the sulfur-based gas absorption film may be poor, and the surface area of the sulfur-based gas absorbent may be reduced, resulting in poor sulfur-based gas absorption.
• the sulfur-containing gas physical absorbent is a gas absorbent that has the effect of physically absorbing the sulfur-containing gas to be absorbed.
• the sulfur-containing gas physical absorbent preferably contains one or more selected from the group consisting of hydrophobic zeolite, bentonite, and sepiolite, each having a SiO / Al molar ratio of 1/1 to 2000/1 .
• Hydrophobic zeolites are zeolites with excellent absorption capabilities for low-polarity molecules such as sulfur-based gases, and have a porous structure. Generally, the higher the molar ratio of SiO 2 /Al 2 O 3 , the more hydrophobic the zeolite. Higher hydrophobicity facilitates absorption of low-polarity molecules such as sulfur-based gases, while conversely, lowering affinity for highly polar molecules such as water makes absorption more difficult.
• the SiO 2 /Al 2 O 3 molar ratio of hydrophobic zeolites is preferably 30/1 to 10,000/1, more preferably 35/1 to 9,000/1, and even more preferably 40/1 to 8,500/1.
• hydrophobic zeolites have high heat resistance and can maintain their absorption effect even when exposed to high temperatures of 230°C or higher.
• hydrophobic zeolites with a molar ratio within the above range are preferably used to balance sulfur-based gas absorption capacity and availability.
• Bentonite is an inorganic substance whose main component is the clay mineral montmorillonite, containing a large amount of layered aluminum phyllosilicate and containing impurities such as quartz and feldspar.
• Bentonite includes, for example, Na-type bentonite, which contains a large amount of Na + ions; Ca-type bentonite, which contains a large amount of Ca2 + ions; and activated bentonite, which is artificially converted to Na-type bentonite by adding a few wt% of sodium carbonate to Ca-type bentonite.
• Sepiolite is a clay mineral whose main component is hydrous magnesium silicate, and has a porous structure with a general chemical composition of Mg 8 Si 12 O 30 (OH 2 ) 4 (OH) 4.6-8H 2 O.
• the pH (3% suspension) is preferably 8.0 to 9.0, more preferably 8.9 to 9.3.
• the sulfur-based gas chemical absorbent is a gas absorbent that has the function of chemically absorbing or decomposing sulfur-based gases in the gas to be absorbed. Because of the chemical absorption or decomposition, it is less susceptible to the influence of water and the like, and once absorbed, sulfur-based gas molecules are less likely to desorb, allowing for efficient absorption. The decomposition products are absorbed by the sulfur-based gas physical absorbent or sulfur-based gas chemical absorbent.
• the sulfur-based gas chemical absorbent preferably contains one or more metal oxides selected from the group consisting of inorganic materials carrying metal oxides, glass containing metals, and glass containing metal ions.
• the metal oxide in the inorganic material carrying metal oxides preferably contains one or more metal oxides selected from the group consisting of CuO, ZnO, and AgO.
• the inorganic material to be supported is preferably an inorganic porous material such as zeolite.
• the metal in the glass mixed with a metal, or the metal species of the metal ions in the glass mixed with metal ions preferably includes one or more species selected from the group consisting of Ca, Mg, Na, Cu, Zn, Ag, Pt, Au, Fe, Al, and Ni.
• the content of the sulfur-based gas absorbent contained in the gas absorbing layer 12 is not particularly limited as long as it absorbs sulfur-based gases. It is preferably at least about 5 parts by mass, more preferably at least about 6 parts by mass, and even more preferably at least about 7 parts by mass, relative to 100 parts by mass of the resin contained in the sulfur-based gas absorbing layer. It is also preferably at most about 60 parts by mass, more preferably at most about 55 parts by mass, and even more preferably at most 50 parts by mass.
• Preferred ranges for the content include approximately 5 to 60 parts by mass, 5 to 55 parts by mass, 5 to 50 parts by mass, 6 to 60 parts by mass, 6 to 55 parts by mass, 6 to 50 parts by mass, 7 to 60 parts by mass, 7 to 55 parts by mass, and 7 to 50 parts by mass.
• the content of the sulfur-based gas absorbent in the entire resin film 1 for an electrical storage device is not particularly limited as long as it is sufficient to absorb sulfur-based gases, and is preferably at least about 0.1 part by mass, more preferably at least about 0.2 part by mass, even more preferably at least about 0.3 part by mass, and is preferably at most about 30 parts by mass, more preferably at most about 27 parts by mass, and even more preferably at most 25 parts by mass, relative to 100 parts by mass of the resin contained in the resin film 1 for an electrical storage device.
• Preferred ranges for the content include approximately 0.1 to 30 parts by mass, approximately 0.1 to 27 parts by mass, approximately 0.1 to 25 parts by mass, approximately 0.2 to 30 parts by mass, approximately 0.2 to 27 parts by mass, approximately 0.2 to 25 parts by mass, approximately 0.3 to 30 parts by mass, approximately 0.3 to 27 parts by mass, approximately 0.3 to 25 ...25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 27 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 30 parts by mass, approximately 0.3 to 27 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 30 parts by mass, approximately 0.3 to 27 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, approximately 0.3 to 25 parts by mass, Furthermore, when a sulfur-based gas absorbent is contained in the gas absorbing layer 12 of the resin film for an electrical
• the content is preferably at most about 60 parts by mass, more preferably at most about 55 parts by mass, and even more preferably at most 50 parts by mass.
• Preferred ranges for the content include approximately 5 to 60 parts by mass, approximately 5 to 55 parts by mass, approximately 5 to 50 parts by mass, approximately 6 to 60 parts by mass, approximately 6 to 55 parts by mass, approximately 6 to 50 parts by mass, approximately 7 to 60 parts by mass, approximately 7 to 55 parts by mass, and approximately 7 to 50 parts by mass.
• the sulfur-based gas absorbent contained in the gas absorbing layer 12 is preferably incorporated via a masterbatch in which the sulfur-based gas absorbent is melt-blended with a resin. Specifically, it is preferable to prepare a masterbatch by melt-blending the sulfur-based gas absorbent with a resin at a relatively high concentration, and then dry-blending the masterbatch with other components to achieve the desired concentration in the sulfur-based gas absorbing layer.
• the sulfur-based gas absorbent and resin to be melt-blended may each be one type or two or more types.
• the content of the sulfur-based gas absorbent in the masterbatch is preferably approximately 20 to 90% by mass, and more preferably approximately 30 to 70% by mass. Within the above range, it is easy to incorporate the necessary and sufficient amount of sulfur-based gas absorbent in a dispersed state into the sulfur-based gas absorbing layer.
• the resin contained in the gas absorbing layer 12 is not particularly limited as long as it does not impair the effects of the present disclosure.
• a thermoplastic resin is preferable, and a heat-sealable resin is more preferable.
• resins include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins.
• the resin forming the resin film 1 for an electricity storage device may also be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins.
• heat-sealable resins such as polyester and polyolefin are preferred.
• polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters.
• Copolymer polyesters include those primarily composed of ethylene terephthalate repeating units.
• polyesters in which ethylene terephthalate repeating units are polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl dicarboxylate), and polyethylene (terephthalate/decane dicarboxylate).
• polyethylene (terephthalate/isophthalate) polyethylene (terephthalate/adipate)
• polyethylene (terephthalate/sodium sulfoisophthalate) polyethylene (terephthalate/sodium isophthalate)
• polyethylene (terephthalate/phenyl dicarboxylate) polyethylene (terephthalate/decane dicarboxylate).
• polybutylene terephthalate is particularly preferred from the viewpoint of improving heat
• 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.
• 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 copoly
• polystyrene resin When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more. Of these, polypropylene is particularly preferred due to its excellent heat-sealing properties.
• the resin contained in the gas absorbing layer 12 may contain an elastomer.
• the elastomer enhances the flexibility of the resin film 1 for use in an electrical storage device while ensuring its durability in high-temperature environments.
• Preferred elastomers include at least one thermoplastic elastomer selected from polyesters, polyamides, polyurethanes, polyolefins, polystyrenes, and polyethers, or thermoplastic elastomer copolymers thereof.
• the elastomer content in the resin film 1 for use in an electrical storage device is not particularly limited, as long as it enhances the flexibility of the resin film 1 for use in an electrical storage device while ensuring its durability in high-temperature environments.
• the content may be approximately 0.1% by mass or more, preferably approximately 0.5% by mass or more, more preferably approximately 1.0% by mass or more, and even more preferably approximately 3.0% by mass or more.
• the content may be, for example, approximately 10.0% by mass or less, approximately 8.0% by mass or less, or approximately 5.0% by mass or less.
• Preferred ranges for the content include approximately 0.1 to 10.0% by mass, approximately 0.1 to 8.0% by mass, approximately 0.1 to 5.0% by mass, approximately 0.5 to 10.0% by mass, approximately 0.5 to 8.0% by mass, approximately 0.5 to 5.0% by mass, approximately 1.0 to 10.0% by mass, approximately 1.0 to 8.0% by mass, approximately 1.0 to 5.0% by mass, approximately 3.0 to 10.0% by mass, approximately 3.0 to 8.0% by mass, and approximately 3.0 to 5.0% by mass.
• the resin content in the gas absorbing layer 12 is, for example, 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more, and is, for example, 95% by mass or less, preferably 90% by mass or less, and more preferably 85% by mass or less.
• the resin film 1 for an electricity storage device contains a water absorbing agent and a sulfur-based gas absorbent
• the water absorbing agent and the sulfur-based gas absorbent may be contained in the same gas absorbing layer 12, or may be contained in different gas absorbing layers 12.
• the gas absorbing layer 12 functions as both a water absorbing layer and a sulfur-based gas absorbing layer.
• the total thickness of the gas absorbing layer 12 is preferably at least about 10 ⁇ m, more preferably at least about 20 ⁇ m, and even more preferably at least about 30 ⁇ m.
• the total thickness is also preferably at most about 300 ⁇ m, more preferably at most about 200 ⁇ m, and even more preferably at most about 100 ⁇ m.
• Preferred ranges include approximately 10 to 300 ⁇ m, approximately 20 to 300 ⁇ m, approximately 30 to 300 ⁇ m, approximately 10 to 200 ⁇ m, approximately 20 to 200 ⁇ m, approximately 30 to 200 ⁇ m, approximately 10 to 100 ⁇ m, approximately 20 to 100 ⁇ m, and approximately 30 to 100 ⁇ m.
• each gas absorbing layer 12 is not particularly limited as long as it exhibits gas absorption ability. From the viewpoint of optimally exhibiting the effects of the present disclosure, the thickness is preferably at least about 10 ⁇ m, more preferably at least about 20 ⁇ m, and even more preferably at least about 30 ⁇ m. The thickness is also preferably at most about 300 ⁇ m, more preferably at most about 200 ⁇ m, and even more preferably at most about 100 ⁇ m.
• Preferred ranges include approximately 10 to 300 ⁇ m, approximately 20 to 300 ⁇ m, approximately 30 to 300 ⁇ m, approximately 10 to 200 ⁇ m, approximately 20 to 200 ⁇ m, approximately 30 to 200 ⁇ m, approximately 10 to 100 ⁇ m, approximately 20 to 100 ⁇ m, and approximately 30 to 100 ⁇ m.
• the adhesive layer 13 is a layer that is provided as needed for the purpose of improving interlayer adhesion.
• the adhesive layer 13 is disposed, for example, between the porous resin layer 11 and the gas absorbing layer 12, between two porous resin layers 11, or between two gas absorbing layers 12, to bond these layers together.
• the adhesive layer 13 is formed from an adhesive capable of bonding layers together.
• the adhesive used to form the adhesive layer 13 may be any of a chemical reaction type, a solvent evaporation type, a hot melt type, a thermocompression type, etc. It may also be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction.
• the adhesive layer 13 may be a single layer or multiple layers.
• adhesive components contained in adhesives include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins.
• polyesters such as polyethylene terephthalate, polybuty
• adhesive components may be used alone or in combination with two or more.
• polyurethane adhesives are preferred.
• the adhesive strength of these adhesive resins can be increased by using an appropriate curing agent in combination.
• the curing agent is selected appropriately from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and other agents depending on the functional groups of the adhesive components.
• polyurethane adhesives examples include polyurethane adhesives containing a first part containing a polyol compound and a second part containing an isocyanate compound. Two-component curing polyurethane adhesives are preferred, with a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the first part and an aromatic or aliphatic polyisocyanate as the second part.
• polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and an isocyanate compound.
• polyurethane adhesives examples include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and a polyol compound.
• polyurethane adhesives examples include polyurethane adhesives obtained by reacting a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance with moisture, such as in the air, and curing the polyurethane compound. It is preferable to use a polyester polyol, which has hydroxyl groups on the side chains in addition to the terminal hydroxyl groups of the repeating unit.
• the second agent examples include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds.
• isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI).
• polyfunctional isocyanate derivatives derived from one or more of these diisocyanates are also included.
• Multimers e.g., trimers
• the adhesive layer 13 may contain other components as long as they do not impair adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, etc.
• a colorant in the adhesive layer 13, the resin film for an electrical storage device can be colored.
• Known colorants such as pigments and dyes can be used as colorants.
• only one type of colorant may be used, or two or more types may be mixed together.
• organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments.
• inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. Other examples include finely powdered mica and fish scale foil.
• colorants carbon black is preferred, for example, to give the resin film for an electricity storage device a black appearance.
• mica is preferred from the perspective of dissipating heat generated by the electricity storage device.
• the average particle size of the pigment is not particularly limited, but may be, for example, approximately 0.03 to 5 ⁇ m, and preferably approximately 0.05 to 2 ⁇ m.
• the average particle size of the pigment is the median diameter measured using a laser diffraction/scattering particle size distribution analyzer.
• the content of colorant in adhesive layer 13 is not particularly limited as long as it colors the outer casing, but may be, for example, approximately 5 to 60% by mass, and preferably 10 to 40% by mass.
• the thickness of adhesive layer 13 is not particularly limited as long as it can bond the layers together, but is, for example, approximately 1 ⁇ m or more, approximately 2 ⁇ m or more. Also, the thickness of adhesive layer 13 is, for example, approximately 10 ⁇ m or less, approximately 5 ⁇ m or less. Preferred ranges for the thickness of adhesive layer 13 include approximately 1 to 10 ⁇ m, approximately 1 to 5 ⁇ m, approximately 2 to 10 ⁇ m, and approximately 2 to 5 ⁇ m.
• the method for producing the resin film for an electricity storage device 1 is not particularly limited as long as the resin film for an electricity storage device 1 can be obtained, and known or commonly used film-forming methods and lamination methods can be applied.
• the resin film for an electricity storage device 1 can be produced by known film-forming and/or lamination methods, such as extrusion or co-extrusion, cast molding, T-die molding, cutting, or inflation.
• the resin film for an electricity storage device 1 is composed of two or more layers, for example, pre-prepared films constituting each layer may be laminated via an adhesive layer, a molten resin composition may be laminated onto a pre-prepared layer by extrusion or co-extrusion, multiple layers may be simultaneously produced and laminated by melt-press bonding, or one or more resins may be applied and dried to coat another layer.
• the layers that make up the resin film 1 for an electrical storage device can be laminated by extrusion or co-extrusion using an extrusion coating method, or they can be laminated via an adhesive layer after film formation using an inflation method or casting method. Even when using the extrusion coating method, lamination may be performed via an adhesive layer if necessary.
• a pre-formed film for the gas absorbing layer 12 (or sulfur-based gas absorbing layer) may be laminated and bonded via an adhesive layer laminated using an extrusion coating method, dry lamination method, non-solvent lamination method, etc. Then, an aging treatment may be performed if necessary.
• the resin composition forming the layer is first heated and melted, and then expanded and stretched in the required width direction using a T-die to form a curtain-like extrusion or co-extrusion.
• the molten resin is then allowed to flow onto the surface to be laminated and sandwiched between a rubber roll and a cooled metal roll, thereby simultaneously forming the layer and laminating and adhering it to the surface to be laminated.
• the melt flow rate (MFR) of the resin component contained in each layer is preferably 0.2 to 50 g/10 min, more preferably 0.5 to 30 g/10 min. If the MFR is lower or higher than the above range, processability is likely to be inferior. Note that in this specification, MFR is a value measured using a method in accordance with JIS K7210.
• the melt flow rate (MFR) of the resin component contained in each layer is preferably 0.2 to 10 g/10 min, and more preferably 0.2 to 9.5 g/10 min. If the MFR is lower or higher than the above range, the processability is likely to be inferior.
• the surface of each layer can be subjected to a desired surface treatment beforehand, as needed.
• pretreatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, and oxidation treatment using chemicals can be optionally performed to form a corona-treated layer, ozone-treated layer, plasma-treated layer, oxidation-treated layer, etc.
• various coating layers such as a primer coating layer, undercoat layer, anchor coating layer, adhesive layer, and vapor-deposited anchor coating layer can be optionally formed on the surface to form a surface treatment layer.
• the various coating layers mentioned above can be resin compositions whose main vehicle is, for example, polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenolic resins, (meth)acrylic resins, polyvinyl acetate resins, polyolefin resins such as polyethylene or polypropylene, or copolymers or modified resins thereof, or cellulose resins.
• main vehicle is, for example, polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenolic resins, (meth)acrylic resins, polyvinyl acetate resins, polyolefin resins such as polyethylene or polypropylene, or copolymers or modified resins thereof, or cellulose resins.
• each layer constituting the resin film for an electricity storage device can be uniaxially or biaxially stretched as needed using a conventional method such as a tenter system or a tubular system.
• the energy storage device 10 of the present disclosure has a structure in which the energy storage device element 4 is sealed with the exterior body 3.
• the energy storage device 10 is sealed, for example, by covering the energy storage device element 4 with the exterior body 3 so that a flange portion (peripheral portion 3a of the exterior body 3) of the exterior body 3 can be formed around the periphery of the energy storage device element 4, and then heat-sealing the flange portion of the exterior body 3 to form a tight seal.
• the position at which the energy storage device resin film 1 is disposed is as described above.
• the configuration of the exterior body 3 included in the energy storage device 10 of the present disclosure will be described in detail below.
• the exterior body 3 may be composed of an exterior material (laminated film) made of a laminate having at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 35 in this order, or may be composed of the exterior material and a lid. That is, the exterior material and the lid constitute an exterior body (exterior body for an electricity storage device) that seals the electricity storage device element.
• the exterior material included in the exterior body 3 may have a laminate structure made of a laminate having at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 35 in this order.
• the exterior body 3 (exterior material), in which a base material layer 31, an optional adhesive layer 32, a barrier layer 33, an optional adhesive layer 34, and a heat-sealable resin layer 35 are laminated in this order.
• the base material layer 31 is the outer layer
• the heat-sealable resin layer 35 is the innermost layer.
• FIGS 9 to 13 show the electricity storage device 10 in which an embossed-type exterior body 3 (exterior material) formed by embossing or the like is used, but as will be described later, the exterior body 3 (exterior material) may be an unformed pouch type.
• pouch types include three-sided seal, four-sided seal, and pillow type, and any type may be used.
• the thickness of the laminate constituting the exterior body 3 (exterior material) is not particularly limited, but from the viewpoint of cost reduction, improved energy density, etc., examples include approximately 300 ⁇ m or less, preferably approximately 250 ⁇ m or less, approximately 210 ⁇ m or less, approximately 190 ⁇ m or less, approximately 180 ⁇ m or less, approximately 155 ⁇ m or less, and approximately 120 ⁇ m or less. Furthermore, from the viewpoint of maintaining the function of the exterior body 3 (exterior material) of protecting the energy storage device elements, the thickness of the laminate constituting the exterior body 3 (exterior material) is preferably approximately 35 ⁇ m or more, approximately 45 ⁇ m or more, approximately 60 ⁇ m or more, approximately 155 ⁇ m or more, and approximately 190 ⁇ m or more.
• preferred ranges for the laminate constituting the exterior body 3 are, for example, about 35 to 300 ⁇ m, about 35 to 250 ⁇ m, about 35 to 210 ⁇ m, about 35 to 190 ⁇ m, about 35 to 180 ⁇ m, about 35 to 155 ⁇ m, about 35 to 120 ⁇ m, about 45 to 300 ⁇ m, about 45 to 250 ⁇ m, about 45 to 210 ⁇ m, about 45 to 190 ⁇ m, about 45 to 180 ⁇ m, about 45 to 155 ⁇ m, about 45 to 120 ⁇ m, about 60 to 300 ⁇ m, about 60 to 250 ⁇ m, about 60 to 2
• thicknesses include approximately 10 ⁇ m, approximately 60 to 190 ⁇ m, approximately 60 to 180 ⁇ m, approximately 60 to 155 ⁇ m, approximately 60 to 120 ⁇ m, approximately 155 to 300 ⁇ m, approximately 155 to 250 ⁇ m, approximately 155 to 210 ⁇ m, approximately 155 to 190 ⁇ m, approximately 155 to 180 ⁇ m
• the resin film 1 for an electricity storage device of the present disclosure can be suitably applied to an exterior body for an all-solid-state battery.
• the thickness of the laminate constituting the exterior body for an all-solid-state battery is not particularly limited, but from the viewpoints of cost reduction, improving energy density, etc., it is preferably about 10,000 ⁇ m or less, about 8,000 ⁇ m or less, or about 5,000 ⁇ m or less.
• suitable thicknesses include 100 to 10,000 ⁇ m, approximately 100 to 8,000 ⁇ m, approximately 100 to 5,000 ⁇ m, approximately 150 to 10,000 ⁇ m, approximately 150 to 8,000 ⁇ m, approximately 150 to 5,000 ⁇ m, approximately 200 to 10,000 ⁇ m, approximately 200 to 8,000 ⁇ m, and approximately 200 to 5,000 ⁇ m, with approximately 100 to 5,000 ⁇ m being particularly preferred.
• the ratio of the total thickness of the base material layer 31, optional adhesive layer 32, barrier layer 33, optional adhesive layer 34, heat-sealable resin layer 35, and optional surface coating layer to the thickness (total thickness) of the laminate constituting the exterior body 3 (exterior material) is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.
• the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior body 3 (exterior material) is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.
• the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior body 3 can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.
• the base material layer 31 is a layer that functions as the base material of the exterior body (exterior material) and forms the outermost layer side.
• the material from which the base layer 31 is made is not particularly limited, as long as it is insulating.
• materials that can be used to make the base layer 31 include polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, and mixtures and copolymers thereof.
• Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantage of being highly resistant to electrolyte and less susceptible to whitening due to adhesion of electrolyte, making them ideal for use as materials to make the base layer 31.
• polyamide film has excellent stretchability and can prevent whitening due to cracking of the resin in the base layer 31 during molding, making it ideal for use as a material to make the base layer 31.
• the substrate layer 31 may be formed from a uniaxially or biaxially stretched resin film, or from an unstretched resin film.
• uniaxially or biaxially stretched resin films, especially biaxially stretched resin films are preferably used as the substrate layer 31 because they have improved heat resistance due to oriented crystallization.
• nylon and polyester are preferred as the resin film forming the substrate layer 31, and biaxially oriented nylon and biaxially oriented polyester are even more preferred. Furthermore, since all-solid-state batteries must withstand temperatures of 150°C or higher, they are often sealed at high temperatures of 200°C or higher, making biaxially oriented polyester the most suitable material.
• the base material layer 31 can also be made by laminating resin films made of different materials to improve pinhole resistance and insulation when used as a packaging material for an electricity storage device.
• resin films made of different materials to improve pinhole resistance and insulation when used as a packaging material for an electricity storage device.
• Specific examples include a multilayer structure in which polyester film and nylon film are laminated together, or a multilayer structure in which biaxially oriented polyester and biaxially oriented nylon are laminated together.
• the resin films may be bonded together using an adhesive, or they may be laminated directly without an adhesive.
• bonding without an adhesive examples include methods in which the films are bonded in a hot-melt state, such as co-extrusion, sand lamination, and thermal lamination. Due to the high-temperature sealing described above, it is desirable that at least the outermost layer be made of biaxially oriented polyester.
• the base layer 31 may be made low-friction to improve formability.
• the coefficient of friction of its surface there are no particular restrictions on the coefficient of friction of its surface, but examples include 1.0 or less.
• Methods for making the base layer 31 low-friction include matte treatment, forming a thin layer of slip agent, and combinations of these.
• the thickness of the substrate layer 31 is, for example, approximately 10 to 50 ⁇ m, and preferably approximately 15 to 30 ⁇ m.
• the adhesive layer 32 is a layer that is disposed on the base material layer 31 as necessary to impart adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.
• the adhesive layer 32 is formed from an adhesive capable of bonding the base material layer 31 and the barrier layer 33.
• the adhesive used to form the adhesive layer 32 may be a two-component curing adhesive or a one-component curing adhesive.
• the bonding mechanism of the adhesive used to form the adhesive layer 32 may be any of a chemical reaction type, solvent evaporation type, thermal melting type, thermal pressure type, etc.
• the resin components of the adhesive that can be used to form the adhesive layer 32 are preferably polyurethane-based two-component curing adhesives; polyamide, polyester, or blend resins of these with modified polyolefins, from the viewpoints of excellent ductility, durability under high humidity conditions, resistance to yellowing, and resistance to thermal degradation during heat sealing, as well as effectively preventing a decrease in the laminate strength between the base layer 31 and the barrier layer 33 and preventing delamination.
• the adhesive layer 32 may be multi-layered with different adhesive components.
• the adhesive layer 32 is multi-layered with different adhesive components, from the viewpoint of improving the laminate strength between the base material layer 31 and the barrier layer 33, it is preferable to select a resin with excellent adhesion to the base material layer 31 as the adhesive component arranged on the base material layer 31 side, and an adhesive component with excellent adhesion to the barrier layer 33 as the adhesive component arranged on the barrier layer 33 side.
• specific examples of the adhesive component arranged on the barrier layer 33 side are preferably acid-modified polyolefin, metal-modified polyolefin, a mixed resin of polyester and acid-modified polyolefin, a resin containing copolymer polyester, etc.
• the thickness of the adhesive layer 32 is, for example, approximately 2 to 50 ⁇ m, and preferably approximately 3 to 25 ⁇ m.
• the barrier layer 33 is a layer that not only improves the strength of the exterior body (exterior material) but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the interior of the electricity storage device.
• the barrier layer 33 is preferably a metal layer, i.e., a layer formed of a metal. Specific examples of metals that constitute the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred.
• the barrier layer 33 can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with any of these vapor deposition films. It is preferably formed from a metal foil, and more preferably from an aluminum foil.
• the barrier layer is more preferably formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).
• a soft aluminum foil such as annealed aluminum
• the layer made of the aforementioned metallic material may contain recycled metallic material.
• recycled metallic material include recycled aluminum alloy, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy material can be obtained, for example, by the manufacturing method described in WO 2022/092231.
• the barrier layer 33 may be made solely of recycled material, or may be made of a mixture of recycled and virgin material.
• recycled metallic material refers to metallic material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes.
• virgin metallic material refers to new metallic material refined from natural metallic resources (raw materials) and is not recycled material.
• the thickness of the barrier layer 33 is preferably about 10 to 200 ⁇ m, and more preferably about 20 to 100 ⁇ m, from the viewpoint of making the exterior body (exterior material) thinner while also making it less likely for pinholes to occur during molding.
• barrier layer 33 it is preferable that at least one surface, and preferably both surfaces, of the barrier layer 33 be chemically treated to stabilize adhesion and prevent dissolution and corrosion.
• chemical treatment refers to a process that forms a corrosion-resistant film on the surface of the barrier layer.
• the adhesive layer 34 is a layer that is provided as needed between the barrier layer 33 and the heat-sealable resin layer 35 in order to firmly bond the heat-sealable resin layer 35 .
• the adhesive layer 34 is formed from an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35.
• an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35 There are no particular restrictions on the composition of the adhesive used to form the adhesive layer, but examples include adhesives made from a polyester polyol compound and an alicyclic isocyanate compound.
• the thickness of the adhesive layer 34 is, for example, approximately 1 to 40 ⁇ m, and preferably approximately 2 to 30 ⁇ m.
• the heat-sealable resin layer 35 corresponds to the innermost layer, and is a layer that seals the electricity storage device elements by heat-sealing the heat-sealable resin layers together when assembling the electricity storage device.
• polystyrene resin examples include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., propylene and ethylene block copolymers), and polypropylene random copolymers (e.g., propylene and ethylene random copolymers); and ethylene-butene-propylene terpolymers.
• polyethylene and polypropylene are preferred.
• the cyclic polyolefin is a copolymer of an olefin and a cyclic monomer.
• the olefin that constitutes the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene.
• the cyclic monomer that constitutes the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene.
• cyclic alkenes are preferred, and norbornene is even more preferred.
• Another example of a constituent monomer is styrene.
• crystalline or amorphous polyolefins preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blend polymers thereof; more preferred are polyethylene, polypropylene, copolymers of ethylene and norbornene, and blend polymers of two or more of these.
• the heat-sealable resin layer 35 may be formed from a single resin component, or may be formed from a blend polymer of two or more resin components. Furthermore, the heat-sealable resin layer 35 may be formed from only one layer, or may be formed from two or more layers of the same or different resin components.
• the thickness of the heat-sealable resin layer 35 is not particularly limited, but may be approximately 2 to 2000 ⁇ m, preferably approximately 5 to 1000 ⁇ m, and more preferably approximately 10 to 500 ⁇ m.
• the resin film 1 for an electricity storage device of the present disclosure can be suitably applied to an exterior body for an all-solid-state battery, and the melting point of the heat-sealable resin layer 35 of the exterior body (exterior material) for an all-solid-state battery is preferably 150 to 250°C, more preferably 180 to 270°C, even more preferably 200 to 270°C, and even more preferably 200 to 250°C.
• examples of resins contained in the heat-sealable resin layer 35 of the exterior body (exterior material) for an all-solid-state battery include polyolefins such as polypropylene and polyethylene, acid-modified polyolefins such as acid-modified polypropylene and acid-modified polyethylene, and polybutylene terephthalate.
• polybutylene terephthalate has excellent heat resistance, so in the exterior body (exterior material) for an all-solid-state battery, the heat-sealable resin layer 35 is preferably formed from a polybutylene terephthalate film.
• the heat-sealable resin layer 35 from a polybutylene terephthalate film, it also has excellent adhesion to the resin film 1 for an electricity storage device of the present disclosure.
• the polybutylene terephthalate film that forms the heat-sealable resin layer 35 may be formed by laminating a pre-prepared polybutylene terephthalate film with the adhesive layer 34, or the resin that forms the polybutylene terephthalate film may be melt-extruded to form a film and then laminated with the adhesive layer 34, or the resin that forms the heat-sealable resin layer 35 and the resin that forms the adhesive layer 34 may be co-extruded to form the film.
• the polybutylene terephthalate film may be a stretched polybutylene terephthalate film or an unstretched polybutylene terephthalate film, with an unstretched polybutylene terephthalate film being preferred.
• the polybutylene terephthalate film further contains an elastomer in addition to polybutylene terephthalate.
• the elastomer enhances the flexibility of the polybutylene terephthalate film while ensuring its durability in high-temperature environments.
• Preferred elastomers include at least one thermoplastic elastomer selected from polyesters, polyamides, polyurethanes, polyolefins, polystyrenes, and polyethers, as well as thermoplastic elastomer copolymers thereof.
• the elastomer content in the polybutylene terephthalate film is not particularly limited, as long as it enhances the flexibility of the polybutylene terephthalate film while ensuring its durability in high-temperature environments.
• it may be about 0.1% by mass or more, preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more, and even more preferably about 3.0% by mass or more.
• the content may also be, for example, about 10.0% by mass or less, about 8.0% by mass or less, or about 5.0% by mass or less.
• Preferred ranges for the content include approximately 0.1 to 10.0% by mass, approximately 0.1 to 8.0% by mass, approximately 0.1 to 5.0% by mass, approximately 0.5 to 10.0% by mass, approximately 0.5 to 8.0% by mass, approximately 0.5 to 5.0% by mass, approximately 1.0 to 10.0% by mass, approximately 1.0 to 8.0% by mass, approximately 1.0 to 5.0% by mass, approximately 3.0 to 10.0% by mass, approximately 3.0 to 8.0% by mass, and approximately 3.0 to 5.0% by mass.
• the heat-sealable resin layer 35 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.
• the heat-sealable resin layer 35 is formed of two or more layers, at least one layer is formed of a polybutylene terephthalate film, and the polybutylene terephthalate film is preferably the innermost layer of the all-solid-state battery exterior.
• the layer that adheres to the adhesive layer 34 is preferably a polybutylene terephthalate film.
• the layers that are not formed of a polybutylene terephthalate film may be formed of, for example, a polyolefin such as polypropylene or polyethylene, or an acid-modified polyolefin such as acid-modified polypropylene or acid-modified polyethylene.
• a polyolefin such as polypropylene or polyethylene
• an acid-modified polyolefin such as acid-modified polypropylene or acid-modified polyethylene.
• the heat-sealable resin layer 35 is preferably formed of only a polybutylene terephthalate film.
• the exterior body of the present disclosure is used as a package for hermetically housing an electricity storage device element, such as a positive electrode, a negative electrode, and an electrolyte. That is, an electricity storage device can be made by housing an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, and a resin film 1 for an electricity storage device, in a package formed from the exterior body (exterior material) of the present disclosure. In other words, an electricity storage device can be made by wrapping an electricity storage device element and a resin film 1 for an electricity storage device in the exterior body of the present disclosure.
• an electricity storage device using an exterior body is provided by covering an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte with the exterior body of the present disclosure, with metal terminals connected to the positive electrode and negative electrode protruding outward, so that a flange portion (a region where the heat-sealable resin layers contact each other) is formed around the periphery of the electricity storage device element, and then heat-sealing the heat-sealable resin layers of the flange portion to form a hermetic seal.
• the package is formed so that the heat-sealable resin portion of the exterior body (exterior material) of the present disclosure faces inward (the surface that contacts the electricity storage device element).
• the package may be formed by overlapping two exterior bodies (exterior materials) with the heat-sealable resin layers facing each other and heat-sealing the peripheries of the overlapped exterior bodies (exterior materials).
• the package may be formed by folding one exterior body (exterior material) over the other and heat-sealing the periphery.
• the edges other than the folded edge may be heat-sealed to form a package with a three-sided seal, or the package may be folded so that a flange is formed and sealed on all four sides.
• the package may be formed by heat-sealing the innermost heat-sealable resin layer and the outermost heat-sealable resin layer.
• the energy storage device element may be sealed by a lid in addition to the exterior material of the exterior body 3. That is, the exterior material and the lid constitute an exterior body (exterior body for an energy storage device) that hermetically seals the energy storage device element.
• the energy storage device element may be housed inside a cylindrical exterior material, and the opening may be closed by the lid.
• the energy storage device element connected to the lid may be housed inside a cylindrical exterior material that has an opening, and the opening may be closed by the lid.
• the lid and exterior material are preferably joined by any means. From the perspective of reducing dead space between the energy storage device element and the exterior material in order to improve the volumetric energy density of the energy storage device, it is preferable that the exterior material be wrapped around the energy storage device element and the lid.
• the lid can be formed, for example, from a resin molded product, a metal molded product, an exterior material, or a combination of these.
• a resin molded product this does not include embodiments in which the lid is composed solely of a film as defined by JIS K6900-1994 [Plastics - Terminology].
• the lid is a metal molded product, the lid also functions as a metal terminal, so the metal terminal can be omitted.
• the lid may be composed of a resin material and a conductive material.
• a recess for accommodating the energy storage device element may be formed in the exterior body (exterior material) by deep drawing or stretch forming.
• a recess may be formed in one exterior body (exterior material) and not in the other exterior body (exterior material), or a recess may also be formed in the other exterior body (exterior material).
• the exterior body of the present disclosure can be suitably used in power storage devices such as batteries (including condensers, capacitors, etc.).
• the exterior body of the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries.
• secondary batteries There are no particular limitations on the type of secondary battery to which the exterior body of the present disclosure can be applied, and examples include lithium-ion batteries, lithium-ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors.
• the exterior body of the present disclosure is suitably applied to lithium-ion batteries and lithium-ion polymer batteries.
• PET film (12 ⁇ m thick) and biaxially oriented nylon (ONy) film (15 ⁇ m thick) were prepared as the substrate layer.
• the PET film and ONy film were bonded together using a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) and then aged to obtain a substrate layer (30 ⁇ m thick) consisting of a PET film (12 ⁇ m thick), an adhesive layer (3 ⁇ m thick after curing), and an ONy film (15 ⁇ m thick) laminated from the outside.
• a two-component urethane adhesive a polyol compound and an aromatic isocyanate compound
• Aluminum foil (JIS H4160:1994 A8021H-O (40 ⁇ m thick)) was also prepared as the barrier layer.
• the ONy film side surface of the substrate layer and the barrier layer were bonded using a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound), and an aging treatment was performed to produce a laminate of substrate layer (thickness 30 ⁇ m)/adhesive layer (thickness 3 ⁇ m after curing)/barrier layer (thickness 40 ⁇ m). Both sides of the aluminum foil were subjected to a chemical conversion treatment.
• the chemical conversion treatment of the aluminum foil was performed by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum foil by roll coating so that the coating amount of chromium was 10 mg/ m2 (dry mass), and baking it.
• maleic anhydride-modified polypropylene as an adhesive layer (40 ⁇ m thick) and random polypropylene as a heat-sealable resin layer (40 ⁇ m thick) were co-extruded onto the barrier layer of the laminate obtained above, resulting in an exterior body (exterior material) (total thickness 153 ⁇ m) layered in the following order: base layer (30 ⁇ m thick) / adhesive layer (3 ⁇ m) / barrier layer (40 ⁇ m) / adhesive layer (40 ⁇ m) / heat-sealable resin layer (40 ⁇ m).
• Example 1 As the gas absorption layer of the resin film for an electricity storage device, a CaO-containing masterbatch (PP base, CaO content 50 wt%) and a thermoplastic resin (polypropylene) were dry-blended and formed into a film at 210°C using a cast film-forming machine, obtaining a gas absorption layer (thickness 50 ⁇ m, water-absorbing agent content 25 wt%). Furthermore, as the porous resin layer of the resin film for an electricity storage device, a non-crosslinked highly expanded polyethylene sheet (thickness 1 mm, density approximately 24.5 kg/m 3 ) was prepared.
• the gas absorption layer and the porous resin layer were stacked to form a two-layer resin film for an electricity storage device.
• the CaO-containing masterbatch was stored in a vacuum-deaerated aluminum bag.
• the CaO-containing masterbatch and the thermoplastic resin (polypropylene) were dry-blended in a dry room (dry room environment 23°C, dew point -40°C) and sealed in a vacuum-deaerated aluminum bag.
• the environment for the cast film formation was 23° C. and 50% RH, and the film after the film formation was sealed together with silica gel in a vacuum-deaerated aluminum bag.
• Example 2 To prepare a single-layer resin film for a storage battery device, a water-absorbing agent masterbatch and thermoplastic resin similar to those in Example 1 were dry-blended with an azodicarbonamide (ADCA) foaming agent masterbatch (LDPE-based), and the mixture was cast at 210°C using a cast film-forming machine to obtain a single-layer resin film for a storage battery device (thickness 1 mm, water-absorbing agent content 25 wt%, density approximately 0.8 g/ cm3 ).
• ADCA azodicarbonamide
• Example 1 Only the gas absorbing layer used in Example 1 was used as a resin film for an electricity storage device.
• Comparative Example 2 Only the porous resin layer used in Example 1 was used as a resin film for an electricity storage device.
• the width of the heat-sealed portion S formed by heat sealing was 10 mm.
• a 7 mm-wide heat seal bar was used, and two heat seals were performed on each side to make the width of the heat-sealed portion S 10 mm.
• the center portion (4 mm width) was heat-sealed twice.
• the heat-sealing conditions for one side in the horizontal direction (TD) were a temperature of 190°C, a surface pressure of 1.0 MPa, and a duration of 3 seconds.
• the heat-sealing conditions for one side in the vertical direction (MD) were a temperature of 190°C, a surface pressure of 2.0 MPa, and a duration of 3 seconds.
• the bag-shaped sample was cut so that the width of the heat-sealed portion on one side in the horizontal direction (TD) was 3 mm, and the sample was dried in a dry room for 24 hours ( Figure 7c).
• a 20 mm x 20 mm piece of resin film A for an electricity storage device was placed through the opening of the bag-shaped sample, and one side of the opening (longitudinal direction (MD direction)) was vacuum-sealed (FCB-200 manufactured by Fuji Impulse Co., Ltd., approximately -100 kPa).
• the heat-sealed side was further heat-sealed using the same heat-sealing conditions and technique so that the width of the heat-sealed portion S was 10 mm, thereby preparing a measurement sample (packaged body 100 as the test subject) (Figure 7e).
• Measurement of water absorption amount All measurements of the amount of moisture absorption were performed in a dry room (dry room environment: 23°C, dew point: -40°C). Measurement samples were stored in a thermo-hygrostat chamber under the respective measurement environments (moisture-containing environments) and measurement times (storage times) listed in Table 1. Separately, measurement samples were stored in a dry room for reference. Next, the measurement samples were removed from the thermo-hygrostat chamber. The resin film for an electricity storage device was removed from the measurement sample, and the amount of moisture absorbed by the gas absorption layer of the resin film for an electricity storage device in the measurement sample was measured using a near-infrared spectrometer in the dry room.
• a VIAVI Micro-NIR (900-1700 nm) was used as the measurement device. Specifically, the resin film for an electricity storage device was removed from the measurement sample, and its absorption spectrum was measured. The resin film for an electricity storage device before moisture absorption was allowed to absorb a known amount of moisture, and the absorption spectrum of the measurement sample was substituted into a regression equation previously prepared from the absorption spectrum measured with the near-infrared spectrometer, to calculate the amount of moisture absorption [ ⁇ g]. The average of the five points on the measurement sample was taken as the amount of water absorption for one measurement sample. The average amount of water absorption was calculated based on the amounts of water absorption for the three measurement samples. The results are shown in Table 1.
• This sample was placed in a rectangular molding die (female mold, surface has a maximum height roughness (nominal Rz value) of 3.2 ⁇ m as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0 mm, ridge R1.0 mm) with an opening of 30 mm (MD) x 60 mm (TD).
• the mold was then placed in a corresponding molding die (male mold, surface has a maximum height roughness (nominal Rz value) of 3.2 ⁇ m as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Annex 1 (Reference)).
• the maximum height roughness (nominal Rz value) of the comparative surface roughness standard piece, as specified in Table 2, is 1.6 ⁇ m.
• a pressing pressure (surface pressure) of 0.25 MPa was applied to a depth of 5 mm for drawing.
• Two of these samples X were prepared, and the heat-sealable resin layers were placed facing each other to align the two molded sections.
• Two 5 mm thick, 30 mm x 50 mm silicone sponge sheets Y were placed in the center of the molded section as pseudo-cells.
• a film Z made by folding a resin film for an electricity storage device (30 mm x 50 mm) three times was inserted into the 5 mm-wide gaps on both short sides of the molded section.
• the three folds were performed by folding a resin film for an electricity storage device (30 mm x 50 mm) in half once at the center of its 50 mm width to make it 25 mm wide, then again in half at the center of the 25 mm width to make it 12.5 mm wide, and again in half at the center of the 12.5 mm width to make film Z 6.25 mm wide and 30 mm long.
• Three sides around the molded portion were then heat-sealed, and the remaining side was vacuum-sealed using a vacuum sealing machine. The exterior body was visually inspected for wrinkles and dents in the margins.
• the resin films for electricity storage devices of Examples 1 and 2 contain a gas absorbent and a porous resin layer, and are disposed between the exterior body of the electricity storage device and the electricity storage device element. As is clear from the results shown in Table 1, the resin films for electricity storage devices of Examples 1 and 2 can effectively adsorb gas inside the electricity storage device, and can also suppress the occurrence of wrinkles, dents, etc. in the exterior body when the electricity storage device element is vacuum-sealed.
• Item 1 A resin film for an electricity storage device that is disposed between an exterior body of an electricity storage device and an electricity storage device element, The resin film for an electricity storage device contains a gas absorbent and a porous resin layer.
• Item 2. The resin film for an electricity storage device according to Item 1, wherein the gas absorbent includes at least one of a water absorbing agent and a sulfur-based gas absorbent.
• the water absorbing agent includes an inorganic water absorbing agent, Item 3.
• the resin film for an electrical storage device according to Item 2 wherein the sulfur-based gas absorbent includes at least one of a sulfur-based gas chemical absorbent and a sulfur-based gas physical absorbent.
• the water-absorbing agent includes at least one selected from the group consisting of calcium oxide, anhydrous magnesium sulfate, magnesium oxide, calcium chloride, zeolite, aluminum oxide, silica gel, alumina gel, and burnt alum, Item 4.
• Item 5 The resin film for an electricity storage device according to any one of Items 1 to 4, wherein at least one layer of the resin film for an electricity storage device contains a heat-sealable resin.
• Item 7. An electricity storage device in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed by an exterior body, Item 7. An electricity storage device, wherein the resin film for an electricity storage device according to any one of Items 1 to 6 is disposed between the exterior body and the electricity storage device.

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