초록 ▼

A releasing pressure and a pressure releasing position, when enclosing films are expanded by gas produced at an abnormal time, are easily and positively configured. A film-enclosed battery (1) has a battery element (2) and two enclosing films (4, 5) for sealing the battery element (2). The enclosing

A releasing pressure and a pressure releasing position, when enclosing films are expanded by gas produced at an abnormal time, are easily and positively configured. A film-enclosed battery (1) has a battery element (2) and two enclosing films (4, 5) for sealing the battery element (2). The enclosing films (4, 5) include heat-sealable resin layers and air-impermeable layers, and the heat-sealable resin layers and air-impermeable layers, and the heat-sealable resin layers that are face each other hold the battery element (2) and seal the battery element (2) when their peripheral edges are thermally fused. A cross-linking structure (8) formed by cross-linking heat-sealable resin layer is formed in one of the enclosing films (4, 5) so that a region in part of a heat-sealed area (6) has a position exposed to a battery element housing unit and another portion in contact with outside air.

대표청구항 ▼

1. A film-encased electric device comprising: an electric device element having a positive pole tab and a negative pole tab connected thereto;encasing films having at least respective heat-sealable resin layers and which surround said electric device element with the heat-sealable resin layers that

1. A film-encased electric device comprising: an electric device element having a positive pole tab and a negative pole tab connected thereto;encasing films having at least respective heat-sealable resin layers and which surround said electric device element with the heat-sealable resin layers that face each other, the facing heat-sealable resin layers being thermally fused to each other along outer peripheral regions thereof to provide a heat-sealed area therealong, said encasing films having an inner space therebetween that serves as an electric device element housing which accommodates said electric device element sealed therein, with said positive pole tab and said negative pole tab extending from said electric device element; anda pressure releaser disposed in a portion of said heat-sealed area on a side from which said positive pole tab and said negative pole tab extend, between said positive pole tab and said negative pole tab, or on a side different from the side from which said positive pole tab and said negative pole tab extend, said pressure releaser being arranged to allow said thermally fused encasing films to peel off progressively more preferentially therein than other regions due to internal pressure buildup in said electric device element housing;said pressure releaser having a cross-linked structure made of a cross-linked resin with a lower peel strength than the rest of the heat-sealed area and disposed in a continuous region in which said cross-linked structure has a portion exposed to said electric device element housing and another portion held in contact with ambient air. 2. The film-encased electric device according to claim 1, wherein said heat-sealed area has a projecting sealed portion projecting toward said electric device element housing, said cross-linked structure being disposed in a range including said projecting sealed portion. 3. The film-encased electric device according to claim 2, wherein said heat-sealed area is formed in said encasing films to provide a bay-shaped non-heat-sealed region in contact with said electric device element housing, said projecting sealed portion being positioned in said non-heat-sealed region. 4. The film-encased electric device according to claim 1, further comprising a gas releaser disposed in outer peripheral regions of said encasing films, said gas releaser being vented to ambient air and not held in contact with said electric device element housing, said cross-linked structure including a region held in contact with said gas releaser as said other portion held in contact with ambient air. 5. The film-encased electric device according to claim 4, wherein said gas releaser is provided as a region in which the encasing films that face each other are not thermally fused to each other. 6. The film-encased electric device according to claim 5, further comprising a tube connected to said gas releaser. 7. The film-encased electric device according to claim 6, wherein said tube is sandwiched between the encasing films that face each other and has an outer peripheral surface bonded to said encasing films. 8. The film-encased electric device according to claim 7, wherein said tube is made of the same resin as the resin of said heat-sealable resin layers and is bonded to said encasing films by thermal fusion. 9. The film-encased electric device according to claim 1, wherein said cross-linked structure is provided by cross-linking the heat-sealable resin layer of said encasing film. 10. The film-encased electric device according to claim 1, wherein said cross-linked structure is provided by a cross-linked resin sheet fused to said encasing film. 11. The film-encased electric device according to claim 1, wherein the cross-linked structure is only formed in the vicinity of the pressure releaser. 12. The film-encased electric device according to claim 1, wherein the pressure releaser is configured to release pressure of 0.05 MPa to 1 MPa from the film-encased electric device. 13. The film-encased electric device according to claim 1, wherein the pressure released by the pressure releaser is inversely related to the degree of cross-linking in the cross-linked structure. 14. A method of manufacturing a film-encased electric device having an electric device element that has a positive pole tab and a negative pole tab connected thereto and surrounded by encasing films having at least respective heat-sealable resin layers and having respective outer peripheral regions thermally fused to each other to provide a heat-sealed area, said encasing films having an inner space therebetween serving as an electric device element housing which accommodates said electric device element sealed therein, with said positive pole tab and said negative pole tab extending from said electric device element, said method comprising the steps of: forming a cross-linked structure made of a cross-linked resin in a continuous region including a portion of said heat-sealed area of the encasing films, on a side of at least one of said encasing films from which said positive pole tab and said negative pole tab extend, between said positive pole tab and said negative pole tab, or on a side different from the side from which said positive pole tab and said negative pole tab extend, said cross-linked structure having a portion exposed to said electric device element housing and another portion held in contact with ambient air;surrounding said electric device element between said encasing films with said cross-linked structure formed therein, said heat-sealable resin layers facing each other around said electric device element, with said positive pole tab and said negative pole tab extending from said electric device element; andthermally fusing the outer peripheral regions of said encasing films which surround said electric device element sandwiched therebetween to seal said electric device element, thereby forming a pressure releaser in a region including the region in which said cross-linked structure is formed, for allowing said thermally fused encasing films to peel off progressively more preferentially therein than other regions due to internal pressure buildup in said electric device element housing,wherein said cross-linked structure has a lower peel strength than the remainder of the thermally fused encasing films. 15. The method according to claim 14, wherein said step of thermally fusing the outer peripheral regions comprises the step of forming a gas releaser that vents to ambient air, from the outer edges of said encasing films to said other portion of said cross-linked structure, by providing a region in which said encasing films are not thermally fused. 16. The method according to claim 14, wherein said step of forming a cross-linked structure comprises the step of applying an electron beam to a region of said encasing films in which said cross-linked structure is to be formed. 17. The method according to claim 15, further comprising the step of connecting a tube to said gas releaser. 18. The method according to claim 17, wherein said step of connecting a tube comprises the steps of sandwiching said tube between the encasing films that face each other and bonding said tube and said encasing films to each other. 19. The method according to claim 14, wherein said step of forming a cross-linked structure comprises the step of cross-linking the heat-sealable resin layer of said encasing film. 20. The method according to claim 14, wherein said step of forming a cross-linked structure comprises the step of fusing a cross-linked resin sheet to said encasing film.