FILM-COVERED BATTERY AND ASSEMBLED BATTERY

Abstract

The invention provides a closed type battery comprising a battery element covered with a covering film and a heat fusion seal portion formed by heat fusion on a periphery of the covering film, wherein the cleaving strength upon an internal pressure rise of a seal portion positioned between a positive electrode terminal and a negative electrode terminal is larger than that of any other seal portion, and a safety valve adapted to release pressure upon a battery's internal pressure rise is located at a portion other than said inter-terminal seal portion. The invention also provides an assembled battery wherein a plurality of closed type batteries are stacked one upon another while a safety valve adapted to release pressure upon an increase in the internal pressure of the battery is located at a position in no contact with the covering film surface of an adjoining battery.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1A is a front view illustrative of a closed type battery according to one embodiment of the invention; FIG. 1B is a plan view of the same; and FIG. 1C is a side view of the same.

FIG. 2A is a front view illustrative of a closed type battery according to another embodiment of the invention; FIG. 2B is a plan view of the same; and FIG. 2C is a side view of the same.

FIG. 3A is a front view illustrative of a closed type battery according to yet another embodiment of the invention; FIG. 3B is a plan view of the same; and FIG. 3C is a side view of the same.

FIG. 4A is a front view illustrative of a closed type battery according to a further embodiment of the invention; FIG. 4B is a plan view of the same; and FIG. 4C is a side view of the same.

FIG. 5A is a front view illustrative of a closed type battery according to a further embodiment of the invention; FIG. 5B is illustrative of how a safety valve works; and FIGS. 5C-5F are illustrative of the safety valve.

FIG. 6A is a view of an assembled battery according to one embodiment of the invention as viewed from a terminal side; FIG. 6B is a side view of the same; and FIG. 6C is a front view of a unit battery forming a part of the assembled battery.

FIG. 7A is a view of an assembled battery according to another embodiment of the invention as viewed from a terminal side; FIG. 7B is a side view of the same; and FIG. 7C is a front view of a unit battery forming a part of the assembled battery.

FIG. 8A is a view of an assembled battery according to yet another embodiment of the invention as viewed from a terminal side; FIG. 8B is a side view of the same; and FIG. 8C is a front view of a unit battery forming a part of the assembled battery.

FIG. 9 is a side view illustrative of an assembled battery according to one embodiment of the invention.

FIG. 10A is a view illustrative of an assembled battery comprising unit batteries connected together according to one embodiment of the invention, as viewed from a terminal side, and FIG. 10B is a view illustrative of an assembled battery comprising unit batteries connected together according to another embodiment of the invention, as viewed from a terminal side.

FIG. 11A is a front view illustrative of a closed type battery using a conventional covering film; FIG. 11B is a plan view of the same; and FIG. 11C is a side view of the same, all as viewed from a terminal side.

Claims

1. A closed type battery comprising a battery element covered with a covering film and a heat fusion seal portion formed by heat fusion on a periphery of the covering film, characterized in that a cleaving strength upon an internal pressure rise of a seal portion positioned between a positive electrode terminal and a negative electrode terminal is larger than that of any other seal portion, and a safety valve adapted to release pressure upon a battery's internal pressure rise is located at a portion other than said inter-terminal seal portion.

2. The closed type battery according to claim 1, wherein a heat fusion seal portion extending from an outer periphery of the battery around said inter-terminal seal portion to within the battery is wider than that positioned at any other seal portion.

3. The closed type battery according to claim 1, wherein said inter-terminal seal portion is provided on its outer surface with a retaining member adapted to press the seal portion when the battery is incorporated in battery drive equipment.

4. The closed type battery according to claim 1, characterized by being a lithium ion battery wherein a composite lithium manganese oxide having a composition formula Li1+xMn2-x-yMyO4-z where 0.03 ≦x≦0.16, 0≦y<0.1, −0.1 ≦z<0.1, and M is at least one selected from Mg, Al, Ti, Co and Ni is used for a positive electrode active substance.

5. An assembled battery, characterized in that unit batteries, each comprising a battery element covered with a covering film and a heat fusion seal portion formed by heat fusion on a periphery of the covering film, wherein a cleaving strength upon an internal pressure rise of a seal portion positioned between a positive electrode terminal and a negative electrode terminal is larger than that of any other seal portion, are connected at least in series or parallel, while a safety valve adapted to release pressure upon a battery's internal pressure rise is located at a portion other than said inter-terminal seal portion and in no contact with a covering film surface of an adjoining battery.

6. The assembled battery according to claim 5, wherein a heat fusion seal portion extending from an outer periphery of the battery around said inter-terminal seal portion to within the battery is wider than that positioned at any other seal portion.

7. The assembled battery according to claim 5, characterized in that closed type batteries, each having a heat-resistant retaining member adapted to press an outer surface of the inter-terminal seal portion, are stacked one upon another.

8. The assembled battery according to claim 5, characterized by comprising a lithium ion battery wherein a composite lithium manganese oxide having a composition formula Li1+xMn2-x-yMyO4-z where 0.03≦x≦0.16, 0≦y≦0.1, −0.1≦z<0.1, and M is at least one selected from Mg, Al, Ti, Co and Ni is used for a positive electrode active substance.