Flat-shaped battery

1. A flat-shaped battery comprising:

an electrode material including a positive material containing a positive active material and a negative material containing a negative active material;

a battery case including a positive case having an opening to house therein the positive material and a negative case having an opening to house therein the negative material, the positive case being a positive electrode and the negative case being a negative electrode;

a plurality of protruding members which are fixed to an inner surface of the battery case, the protruding members extending inwardly from the inner surface of the battery case and being inserted in the electrode material housed in the battery case, and

an elastic member which is placed between a surface of the electrode material into which the protruding members are inserted and the inner surface of the battery case to bias the electrode material toward an inner surface opposite to the inner surface of the battery case, wherein

the protruding members and the elastic member are integrally formed.

2. The flat-shaped battery as defined in claim 1 , further comprising a flat plate member fixed to the inner surface of the battery case the flat plate member having a plurality of end portions, wherein

one of the end portions of the flat plate member is folded so that the protruding member is formed, and

the other one of the end portions of the flat plate member is folded so that the elastic member is formed as a plate spring.

3. The flat-shaped battery as defined in claim 1 , wherein

the electrode material has a flat shape and the individual protruding members are inserted into one end face of the electrode material in a thicknesswise direction thereof, and

a protrusion size to which the protruding members protrude inward of the battery case is set to within a range from 1/10 to ⅔ of a thickness of the electrode material.

4. The flat-shaped battery as defined in claim 1 , wherein the protruding members and the elastic member are formed from an electroconductive material.

5. The flat-shaped battery as defined in claim 1 , wherein the protruding members each have a pointed tip end.

6. The flat-shaped battery as defined in claim 1 , further comprising:

a separator interposed between the positive material and the negative material, and

a gasket for providing a seal between the opening of the positive case and the opening of the negative case, wherein

the individual protruding members are fixed to a bottom face of the positive case, and

the elastic member is placed between the bottom face of the positive case and the positive material to bias the positive material toward the negative material.

7. The flat-shaped battery as defined in claim 6 , wherein

in the bottom face of the positive case, a step portion is formed so that a region of the bottom face inner than an edge portion thereof becomes lower than the edge portion, and

the positive material is placed in the region inner than the edge portion while the individual protruding members are fixed in the region inner than the edge portion.

8. The flat-shaped battery as defined in claim 6 , further comprising:

a ring-shaped member which covers a side face and a bottom-face edge portion of the positive material and which is formed from an electroconductive material higher in rigidity than the positive material, wherein

the elastic member is formed from an electroconductive material and biases a bottom face of the ring-shaped member to hold conduction between the positive material and the bottom face of the positive case.

9. A flat-shaped battery comprising:

a positive material containing a positive active material;

a negative material containing a negative active material;

a separator interposed between the positive material and the negative material,

a positive case having an opening to house therein the positive material;

a negative case having an opening to house therein the negative material;

a gasket for providing a seal between the opening of the positive case and the opening of the negative case; and

a positive-material fixing member formed of a plate member which is fixed to a bottom face of the positive case to fix the positive material housed in the positive case at a housing position, wherein

the positive-material fixing member has a plurality of protruding members formed by folding one end portion of the plate member inward of the positive case, and a plate spring formed by folding the other end portion of the plate member inward of the positive case, and

with the protruding members inserted in the positive material, the positive material is biased toward the negative material by the plate spring so that the positive material is fixed at the housing position.

10. The flat-shaped battery as defined in claim 9 , wherein

in the bottom face of the positive case, a step portion is formed so that a region of the bottom face inner than an edge portion thereof becomes lower than the edge portion, and

the positive material is placed in the region inner than the edge portion while the individual protruding members and the plate spring are placed in the region inner than the edge portion.

11. The flat-shaped battery as defined in claim 9 , further comprising:

a ring-shaped member which covers a side face and a bottom-face edge portion of the positive material and which is formed from an electroconductive material higher in rigidity than the positive material, wherein

the positive-material fixing member is formed from an electroconductive material, and

the plate spring biases a bottom face of the ring-shaped member to hold conduction between the positive material and the bottom face of the positive case.

12. A tire pressure detection sensor for use in vehicles, including the flat-shaped battery as defined in claim 9 as a power supply source for the sensor.