Battery
A battery includes a bottomed cylindrical case body that accommodates an electrode body and a bottom-portion insulating plate ( 19 ) that is disposed between the electrode body and a bottom portion of the case body. The bottom portion of the case body has a gas discharge port that opens when an internal pressure of the battery reaches a predetermined pressure. The bottom-portion insulating plate ( 19 ) has a through hole. An aperture ratio, which is a ratio of an area of the through hole with respect to a total area of the insulating plate, is greater than or equal to 10% and less than or equal to 40%. A Young's modulus of the bottom-portion insulating plate at 25° C. is 10 GPa or greater.
1. A battery comprising:
a bottomed cylindrical case body that accommodates an electrode body; and
a bottom-portion insulating plate that is disposed between the electrode body and a bottom portion of the case body,
wherein the bottom portion of the case body has a gas discharge port that opens when an internal pressure of the battery reaches a predetermined pressure,
wherein the bottom-portion insulating plate has a plurality of through holes,
wherein an aperture ratio, which is a ratio of an area of the through hole with respect to a total area of the insulating plate, is greater than or equal to 10% and less than or equal to 40%, and
wherein a Young's modulus of the bottom-portion insulating plate at 25° C. is 10 GPa or greater, and
wherein the plurality of the through holes include a first through hole and a plurality of second through holes, the first through hole being formed in a range including a center of the bottom-portion insulating plate, the plurality of second through holes being formed around the first through hole,
wherein a diameter of a circle, which is a circle whose radius extends from the center of the bottom-portion insulating plate to inner edges of the second through holes that are closest to the center is smaller than a diameter of the gas discharge port,
wherein a portion of the plurality of second through holes is located out of peripheral edge of the gas discharge port.
2. The battery according to claim 1 , wherein the second through holes are formed at equal intervals on one concentric circle whose center is the first through hole.
3. The battery according to claim 1 , wherein an area of the first through hole is greater than or equal to 10% and less than or equal to 45% of a total area of the through holes.
4. The battery according to claim 1 , further comprising:
a sealing body that has a gas discharge mechanism and that covers an opening in the case body; and
an upper-portion insulating plate that is disposed between the electrode body and the sealing body,
wherein the Young's modulus of the bottom-portion insulating plate is greater than a Young's modulus of the upper-portion insulating plate.
5. The battery according to claim 4 , wherein an opening area of the gas discharge port is greater than an opening area of the gas discharge mechanism of the sealing body.