Film-covered electric device having pressure release opening

• US 20050158622A1
• Filed: 01/14/2005
• Published: 07/21/2005
• Est. Priority Date: 01/16/2004
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Lamilion Energy Limited
• Inventors: Otohata, Makihiro, Mizuta, Masatomo, Yageta, Hiroshi, Oikawa, Kiyokazu, Mankyu, Toshihiko
• Granted Patent: US 7,267,906 B2
• Time in Patent Office: Days
• US Class Current: 429/185
• CPC Class Codes: H01G 9/08 Housing; Encapsulation
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/121 Organic material
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/129 with two or more layers of only organic material
• CPC Class Codes: H01M 50/133 Thickness
• CPC Class Codes: H01M 50/136 Flexibility or foldability
• CPC Class Codes: H01M 50/30 Arrangements for facilitating escape of gases
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y10T 428/239 Complete cover or casing

Abstract

A film-covered electric device has an electric device element and casing films. The casing films include a sealing area formed by thermally fusing the facing surfaces of the casing films together around the periphery of the electric device element, an electric device element receiving part encapsulating the electric device element inside the sealing area, and unfused portions formed in the shape of cove communicating with the electric device element receiving part. The casing films further include a stress concentrating portion touching the unfused portions for concentrating thereon the peeling stress of the casing films generated at the sealing area by the expansion of the electric device element receiving part, and a pressure releasing part is formed in the stress concentrating portion.

Claims

1. A film-covered electric device having an electric device element, and a casing film arranged for enclosing said electric device element to seal said electric device element, said casing film comprising:

a sealing area formed by thermally fusing the facing surfaces of said casing film together throughout the perimeter of said casing film around the periphery of said electric device element;

an electric device element receiving part formed inside said sealing area as a space for encapsulating said electric device element;

at least one unfused portion communicating with said electric device element receiving part, and having a shape of cove opening to said electric device element receiving part;

a stress concentrating portion touching said unfused portion for concentrating thereon peeling stress of said casing film, the peeling stress being generated by the expansion of said electric device element receiving part according to the rise of inside pressure of said electric device element receiving part; and

a pressure release part formed within said stress concentrating portion for opening the inside of said electric device element receiving part to the outside thereof by peeling said casing film.

2. The film-covered electric device according to claim 1, wherein said sealing area is formed protruding into the area where said unfused portion is provided.

3. The film-covered electric device according to claim 1, wherein said pressure release part is a hole or a slit formed at least in one side of said casing film overlaid at said stress concentrating portion.

4. The film-covered electric device according to claim 1, wherein two unfused portions are provided in spaced relationship with each other along the periphery of said sealing area, and said stress concentrating portion is located between said two unfused portions.

5. The film-covered electric device according to claim 4, wherein said stress concentrating portion is formed as a fused protrusion protruding toward said electric device element receiving part from said sealing area positioned outside said two unfused portions.

6. The film-covered electric device according to claim 5, wherein said fused protrusion has a shape tapering toward said electric device element receiving part.

7. The film-covered electric device according to claim 4, wherein said stress concentrating portion is formed as an island-shaped fused portion located between said two unfused portions.

8. The film-covered electric device according to claim 1, wherein one unfused portion is provided in said casing film, and both sides of said unfused portion are said stress concentrating portions.

9. The film-covered electric device according to claim 8, wherein said pressure release part is formed on each of said stress concentrating portions provided on both sides of said unfused portion.

10. The film-covered electric device according to claim 1, wherein said pressure release part is so positioned that, when the inside of said electric device element receiving part opens to the outside, the inside pressure of said electric device element receiving part increases over the atmospheric pressure by 0.1 to 0.2 MPa.

11. The film-covered electric device according to claim 1, wherein said electric device element is a chemical battery element or a capacitor element.