KR-102958721-B1 - CASING MATERIAL FOR ELECTRICITY STORAGE DEVICE AND ELECTRICITY STORAGE DEVICE INCLUDING SAME

Abstract

An outer layer for a capacitor, comprising a substrate layer, an adhesive-facilitating treatment layer formed on one side of the substrate layer, an adhesive layer formed on a side opposite to the substrate layer of the adhesive-facilitating treatment layer, a metal foil layer formed on a side opposite to the adhesive-facilitating treatment layer of the adhesive layer, and a sealant layer disposed on a side opposite to the adhesive layer of the metal foil layer, wherein the substrate layer comprises a biaxially stretched film, and in a tensile test (test specimen shape: test specimen type 5 specified in JIS K7127, chuck distance: 60 mm, tensile speed: 50 mm/min), the breaking strength in at least one of four directions [0° (MD), 45°, 90° (TD), 135°] is 240 MPa or more, and the elongation in at least one direction is 80% or more.

Inventors

• 이주인 와타루

Assignees

• 도판 홀딩스 가부시키가이샤

Dates

Publication Date

20260507

Application Date

20150714

Priority Date

20140716

Claims (9)

1. The apparatus comprises a substrate layer, an adhesion-enhancing treatment layer formed on one side of the substrate layer, an adhesive layer formed on the side of the adhesion-enhancing treatment layer opposite to the substrate layer, a metal foil layer formed on the side of the adhesive layer opposite to the adhesion-enhancing treatment layer, and a sealant layer disposed on the side of the metal foil layer opposite to the adhesive layer. The above substrate layer comprises a tubular biaxial polyamide stretched film and is a layer having a breaking strength in four directions [0°(MD), 45°, 90°(TD), 135°] of 221 MPa or more and 268 MPa or less in a tensile test (specimen shape: Type 5 specified in JIS K7127, chuck distance: 60 mm, tensile speed: 50 mm/min), and also having an elongation in four directions [0°(MD), 45°, 90°(TD), 135°] of 81% or more and 102% or less. The above adhesion-facilitating treatment layer is a layer formed by a coating agent containing at least one resin selected from the group consisting of polyester resin, acrylic resin, polyurethane resin, epoxy resin, and acrylic graft polyester resin, silica microparticles, and water. Exterior material for capacitors.
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3. In claim 1, the substrate layer is an outer material for a capacitor, wherein the fracture strength in at least one of the four directions in the tensile test is less than 240 MPa.
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5. An exterior material for a capacitor, wherein, in claim 1, it further comprises a substrate protection layer formed on a surface opposite to the adhesive-facilitating treatment layer of the substrate layer.
6. An outer casing for a storage device according to claim 1, wherein the thickness of the substrate layer is 6 to 40 μm.
7. An outer casing for a capacitor according to claim 1, wherein the thickness of the adhesion-facilitating treatment layer is 0.02 to 0.5 μm.
8. An exterior material for a capacitor, wherein the adhesive layer contains a pigment, in accordance with claim 1.
9. A battery element comprising an electrode, a lead extending from the electrode, and a container for housing the battery element, The above container is a capacitor device in which the sealant layer is formed on the inside of the outer material for the capacitor device described in claim 1.

Description

CASING MATERIAL FOR ELECTRICITY STORAGE DEVICE AND ELECTRICITY STORAGE DEVICE INCLUDING SAME The present invention relates to an outer casing for a battery storage device and a battery storage device using the same. As for energy storage devices, secondary batteries such as lithium-ion batteries, nickel-hydrogen batteries, and lead-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors, are known. Due to the miniaturization of portable devices and limitations on installation space, further miniaturization of energy storage devices is required, and lithium-ion batteries with high energy density are attracting attention. Conventionally, metal cans were used as casing materials for lithium-ion batteries, but multilayer films have come into use as they are lightweight, have high heat dissipation properties, and can be manufactured at low cost. In lithium-ion batteries using the above-mentioned multilayer film as an outer casing, a configuration is adopted in which the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) are covered by an outer casing containing an aluminum foil layer to prevent moisture intrusion into the interior. A lithium-ion battery employing such a configuration is referred to as an aluminum laminate type lithium-ion battery. Aluminum laminate type lithium-ion batteries are known as embossed type lithium-ion batteries, for example, in which a concave portion is formed by cold forming on a part of the outer casing to accommodate the battery contents, and the remaining part of the outer casing is folded and the edges are sealed with a heat seal (hereinafter referred to as "unilaterally formed batteries"). Furthermore, recently, lithium-ion batteries are also being manufactured with the aim of increasing energy density by forming concave portions on both sides of the bonded outer casing to accommodate more battery contents (hereinafter referred to as "doublely formed batteries"). Doublely formed batteries have problems such as difficulty in alignment when bonding the outer casings together. However, to obtain an energy density equivalent to that of doublely formed batteries using unilaterally formed batteries, the formation of deeper concave portions is required. The energy density of a lithium-ion battery can be increased by making the concave portion formed by cold forming deeper. However, the deeper the concave portion formed, the more prone it is for pinholes or fractures to occur in the outer material during forming, which leads to a decrease in formability. Therefore, a polyamide film with excellent formability is used as the substrate layer of the outer material, and this substrate layer is bonded to a metal foil via a bonding layer to protect the metal foil. At this time, adhesion between the substrate layer and the adhesive layer is required. As a method to improve the adhesion between the substrate layer and the adhesive layer, a corona treatment is performed on the surface of the substrate layer (see, for example, Patent Documents 1 and 2). In addition, polyamide films have low resistance to the electrolyte, which is the content of a lithium-ion battery. Therefore, when the electrolyte adheres to the polyamide film during the lithium-ion battery manufacturing process, the polyamide film may dissolve, resulting in appearance defects. Accordingly, an exterior material has been proposed in which a polyethylene terephthalate (PET) film is further laminated on the outer side of a polyamide film to provide electrolyte resistance on the surface of the substrate layer (see, for example, Patent Document 3). FIG. 1 is a schematic cross-sectional view of an outer casing for a battery storage device according to one embodiment of the present invention. FIG. 2 is a drawing illustrating an embossed type exterior material obtained using an exterior material for a capacitor device according to one embodiment of the present invention, (a) is a perspective view thereof, and (b) is a longitudinal cross-sectional view along line bb of the embossed type exterior material shown in (a). FIG. 3 is a perspective view illustrating a process for manufacturing a secondary battery using an exterior material for a storage device according to one embodiment of the present invention, (a) shows a state in which an exterior material for a storage device is prepared, (b) shows a state in which an exterior material for a storage device processed into an embossing type and a battery element are prepared, (c) shows a state in which a part of the exterior material for a storage device is folded and the end is melted, and (d) shows a state in which both sides of the folded part are folded upward. FIG. 4 is a schematic cross-sectional view of an outer casing for a storage device according to another embodiment of the present invention. Suitable embodiments of the present invention will be described in detail below with reference to the drawings. In