# US 2026/0094902 A1 · Resin film for power storage device, and power storage device

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- Number: US 2026/0094902 A1
- Document ID: US20260094902A1
- Status: Published application
- Kind: A1
- Application number: 19/111,570
- Filed: 2023-10-12
- Published: 2026-04-02
- Earliest claimed: 2022-10-12
- Assignees: Dai Nippon Printing Co., Ltd.
- Applicants: Dai Nippon Printing Co., Ltd.
- Inventors: Tsubasa KAGATA; Miho SASAKI; Naoya TAKEUCHI
- Web page: https://patentgrep.com/patent/US20260094902A1

## CPC

- B32B 27/20: using fillers, pigments, thixotroping agents
- H01M 50/141: for protecting against humidity
- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B32B 27/36: comprising polyesters
- H01G 2/10: Housing; Encapsulation
- H01G 11/78: Cases; Housings; Encapsulations; Mountings
- H01M 50/105: Pouches or flexible bags
- H01M 50/117: Inorganic material
- H01M 50/119: Metals
- H01M 50/121: Organic material
- H01M 50/122: Composite material consisting of a mixture of organic and inorganic materials
- H01M 50/124: having a layered structure
- H01M 50/129: with two or more layers of only organic material
- H01M 50/131: characterised by physical properties, e.g. gas permeability, size or heat resistance
- H01M 50/184: characterised by their shape or structure
- H01M 50/186: characterised by the disposition of the sealing members
- H01M 50/193: Organic material
- H01M 50/474: characterised by their position inside the cells
- H01M 50/483: Inorganic material
- H01M 50/486: Organic material
- H01M 50/489: Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M 50/531: Electrode connections inside a battery casing
- H01M 50/553: Terminals adapted for prismatic, pouch or rectangular cells
- B32B 2250/02: 2 layers
- B32B 2250/03: 3 layers
- B32B 2250/242: All polymers belonging to those covered by group B32B27/32
- B32B 2250/244: All polymers belonging to those covered by group B32B27/36
- B32B 2264/102: Oxide or hydroxide
- B32B 2307/206: Insulating
- B32B 2307/31: Heat sealable
- B32B 2307/726: Permeability to liquids, absorption
- B32B 2307/728: Hydrophilic
- B32B 2457/10: Batteries
- H01G 11/80: Gaskets; Sealings
- Y02E 60/10: Energy storage using batteries
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A resin film for a power storage device constituted of two or more layers, and said two or more layers include: at least one layer of a layer A having a content of a water absorbent of at least 5 mass %; and at least one layer of a layer B having a content of water absorbent of less than 5 mass %.

## Claims

### Claim 1

A resin film for electrical storage devices, comprising two or more layers, wherein the two or more layers include at least one layer A having a water absorbent content of 5 mass % or more, and at least one layer B having a water absorbent content of less than 5 mass %.

### Claim 2 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein the at least one layer B has a water absorbent content of 0%.

### Claim 3 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein at least one of the two or more layers has a solid particle content of less than 5 mass %.

### Claim 4 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein the water absorbent includes an inorganic water absorbent.

### Claim 5 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein the water absorbent contains 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 dried alum.

### Claim 6 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein at least one of the two or more layers contains a heat-sealable resin.

### Claim 7 (depends on 6)

The resin film for electrical storage devices according to claim 6, wherein the heat-sealable resin contains at least one selected from the group consisting of polyester and polyolefin.

### Claim 8 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein the resin film for electrical storage devices after water absorption has a dielectric breakdown strength of 40 kV/mm or more as measured by the following measurement method:
(measurement of dielectric breakdown strength after absorption of water)
a 10 cm-square resin film for electrical storage devices is provided, and immersed in hot water at 80° C.; the immersion is continued until the water absorbent in the resin film for electrical storage devices absorbs water to full capacity, thereby obtaining a resin film for electrical storage devices after absorption of water; a water-absorbing capacity of the resin film for electrical storage devices is calculated from a weight of the film before and after immersion; next, in accordance with the provisions of JIS C 2110-1: 2016, the dielectric breakdown strength of the resin film for electrical storage devices after absorption of water is measured under measurement conditions of measurement environment: 23° C. in the air, pressure boosting method: short-time method (alternating-current, 50 Hz), pressure boosting rate: 0.3 kV/s, and electrode: 25 mmφ cylinder/75 mmφ cylinder; and a measured value is an average value for five samples.

### Claim 9 (depends on 1)

The resin film for electrical storage devices according to claim 1, wherein the resin film for electrical storage devices is 1) disposed between an exterior material for electrical storage devices and an electrical storage device element, 2) used as a heat-sealable resin layer of an exterior material for electrical storage devices, 3) used as an adhesive layer between a barrier layer and a heat-sealable resin layer of an exterior material for electrical storage devices, or 4) used as an adhesive film for metal terminal which is interposed between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for electrical storage devices which seals the electrical storage device element.

### Claim 10 (depends on 1)

An electrical storage device in which an electrical storage device element including at least a positive electrode, a negative electrode and an electrolyte is housed in a packaging formed of an exterior material, wherein the resin film for electrical storage devices according to claim 1 is disposed between the exterior material and the electrical storage device.