Film-armored battery and method of manufacturing the battery
In a film-packed battery which stores a battery element ( 9 ) with packing films ( 8 a, 8 b ) and sealed by heat-sealing heat-sealed surfaces of the packing films around the battery element, a heat-sealed portion ( 6 ) projecting toward a battery element is provided at part of a heat-sealed portion ( 5 ), and a gas releasing portion ( 7 ) is formed close to the projecting heat-sealed portion. A pressure safety valve for safely releasing a gas to the outside when the gas is generated in the battery is provided without lowering the reliability of the battery.
1. A film-packed battery comprising:
a battery element comprising an electrolyte;
a packing film which stores the battery element and includes:
a main heat-sealed portion which is formed around said battery element; and
a projecting heat-sealed portion which projects from said main heat-sealed portion toward said battery element; and
a gas releasing portion formed in said main heat-sealed portion adjacent to said projecting heat-sealed portion,
wherein said packing film comprises a rectangular shape in a plan view, and
wherein a side of said projecting heat-sealed portion which is adjacent to said battery element projects toward said battery element to come closer to the battery element than a side of said main heat-sealed portion which is adjacent to said battery element and adjacent to said projecting heat-sealed portion.
2. A film-packed battery according to claim 1 , wherein said gas releasing portion is formed at that portion of said heat-sealed portion which is not heat-sealed.
3. A film-packed battery according to claim 1 , wherein said gas releasing portion comprises an incision that reaches said projecting heat-sealed portion.
4. A film-packed battery according to claim 1 , wherein said gas releasing portion comprises a notch that reaches said projecting heat-sealed portion.
5. A film-packed battery according to claim 1 , wherein said gas releasing portion is formed by forming a hole in said projecting heat-sealed portion.
6. A film-packed battery according to claim 1 , wherein said projecting heat-sealed portion and gas releasing portion are formed on a side from which electrode lead wires extend.
7. A film-packed battery according to claim 1 , wherein said projecting heat-sealed portion and gas releasing portion are formed in an electrode lead wire extending portion.
8. A film-packed battery according to claim 1 , wherein said projecting heat-sealed portion and gas releasing portion are formed at a corner of said packing film.
9. A film-packed battery according to claim 1 , wherein said projecting heat-sealed portion and gas releasing portion are formed at substantially a center of a side of said packing film.
10. A film-packed battery according to claim 1 , wherein said gas releasing portion includes a seal portion having a pressure resistance which is less than a pressure resistance of said main heat-sealed portion adjacent to said gas releasing portion.
11. A film-packed battery according to claim 10 , wherein said seal portion is heat-sealed at a temperature lower than that for another heat-sealed portion.
12. A film-packed battery according to claim 10 , wherein said seal portion has a heat-sealing width less than a heat-sealing width of said adjacent main heat-sealed portion.
13. A film-packed battery according to claim 1 , wherein said gas releasing portion is provided at a position on a side of said projecting heat-sealed portion which is opposite a direction in which said projecting heat-sealed portion projects.
14. A film-packed battery comprising:
a battery element;
a packing film which houses the battery element and includes:
a main heat-sealed portion which is formed around said battery element; and
a projecting heat-sealed portion which projects from said main heat-sealed portion toward said battery element; and
a gas-releasing portion formed in said main heat-sealed portion adjacent to said projecting heat-sealed portion,
wherein said packing film comprises a rectangular shape in a plan view, and
wherein a side of said projecting heat-sealed portion which is adjacent to said battery element projects toward said battery element to come closer to the battery element than a side of said main heat-sealed portion which is adjacent to said battery element and adjacent to said projecting heat-sealed portion.
15. The battery of claim 14 , wherein said packing film comprises:
a first film formed on a side of said battery element; and
a second film formed on another side of said battery element, said first film being heat-sealed to said second film in said main heat-sealed portion and said projecting heat-sealed portion.
16. The battery of claim 15 , wherein said gas releasing portion comprises a hole formed in one of said first and second films.
17. The battery of claim 14 , wherein said projecting portion comprises plural projecting portions, and said gas releasing portion comprises plural gas releasing portions.
18. A battery of claim 14 , wherein said gas releasing portion is provided at a position on a side of said projecting heat-sealed portion which is opposite a direction in which said projecting heat-sealed portion projects.