Flat-shaped battery

1. A flat-shaped battery comprising:

an outer can that is open upward;

a sealing can that is open downward; and

a gasket that is placed between the outer can and the sealing can to seal a space between them,

wherein the outer can comprises a base plate and a cylindrical surrounding wall, and the base plate comprises a recess where a central portion of the base plate curves downward, and an annular peripheral portion surrounding the recess,

the surrounding wall of the outer can comprises a straight portion that extends upward and perpendicular to the base plate,

the sealing can comprises a housing in the form of an inverted dish, a flange that projects outward from a lower end of an opening of the housing, and a single outer surrounding wall without folding that extends downward from an outside edge of the flange so as to be perpendicular to the flange,

the outer surrounding wall of the sealing can is arranged perpendicular to the base plate of the outer can and is tapered so that a thickness of the outer surrounding wall of the sealing can becomes smaller toward an opening of the sealing can,

the gasket comprises a base that receives a lower end of the outer surrounding wall of the sealing can, and an outer cylindrical wall that extends upward from the base and is disposed between the surrounding wall of the outer can and the outer surrounding wall of the sealing can, and the base of the gasket is in direct contact with the base plate of the outer can,

the surrounding wall of the outer can has a curved edge such that the surrounding wall at an opening of the outer can is bent toward an axis of the outer can and positioned laterally with respect to the outer surrounding wall of the sealing can,

the curved edge presses an upper end of the outer cylindrical wall of the gasket against an upper end of the outer surrounding wall of the sealing can,

an end position of the curved edge of the surrounding wall of the outer can is located closer to the axis of the outer can than an inner surface of the outer surrounding wall of the sealing can,

a lateral distance from a first virtual extension surface of the inner surface of the outer surrounding wall of the sealing can to the end position of the curved edge is set within a range of 10% to 300% of a thickness of the outer surrounding wall of the sealing can, and

at a point on a curve where a second virtual extension surface of an outer surface of the outer surrounding wall of the sealing can intersects an outer surface of the surrounding wall of the outer can, an inclination angle between the second virtual extension surface and a tangential virtual plane contacting the point is set within a range of 65° to 105° when the angle is measured from the second virtual extension surface upward.

2. The flat-shaped battery according to claim 1 , wherein a bend position at which the straight portion of the surrounding wall of the outer can starts to be bent is located higher than the lower end of the opening of the housing.

3. A flat-shaped battery comprising:

an outer can that is open upward;

a sealing can that is open downward; and

a gasket that is placed between the outer can and the sealing can to seal a space between them,

wherein the outer can comprises a base plate and a cylindrical surrounding wall, and the base plate comprises a recess where a central portion of the base plate curves downward, and an annular peripheral portion surrounding the recess,

the surrounding wall of the outer can comprises a straight portion that extends upward and perpendicular to the base plate,

the sealing can comprises a housing in the form of an inverted dish, a flange that projects outward from a lower end of an opening of the housing, and a single outer surrounding wall without folding that extends downward from an outside edge of the flange so as to be perpendicular to the flange,

the outer surrounding wall of the sealing can is arranged perpendicular to the base plate of the outer can and is tapered so that a thickness of the outer surrounding wall of the sealing can becomes smaller toward an opening of the sealing can,

the gasket comprises a base that receives a lower end of the outer surrounding wall of the sealing can, and an outer cylindrical wall that extends upward from the base and is disposed between the surrounding wall of the outer can and the outer surrounding wall of the sealing can, and the base of the gasket is in direct contact with the base plate of the outer can,

the surrounding wall of the outer can has a curved edge such that the surrounding wall at an opening of the outer can is bent toward an axis of the outer can and positioned laterally with respect to the outer surrounding wall of the sealing can,

the curved edge presses an upper end of the outer cylindrical wall of the gasket against an upper end of the outer surrounding wall of the sealing can,

an end position of the curved edge of the surrounding wall of the outer can is located closer to the axis of the outer can than an inner surface of the outer surrounding wall of the sealing can,

a lateral distance from a first virtual extension surface of the inner surface of the outer surrounding wall of the sealing can to the end position of the curved edge is set within a range of 10% to 300% of a thickness of the outer surrounding wall of the sealing can,

at a point on a curve where a second virtual extension surface of an outer surface of the outer surrounding wall of the sealing can intersects an outer surface of the surrounding wall of the outer can, an inclination angle between the second virtual extension surface and a tangential virtual plane contacting the point is set within a range of 65° to 105° when the angle is measured from the second virtual extension surface upward, and

a bend position at which the straight portion of the surrounding wall of the outer can starts to be bent is located higher than the lower end of the opening of the housing.