Battery packaging material having a valve device
A battery includes a battery element, a housing body, and a valve device. The housing body is constituted by at least one laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer layered in that order and houses the battery element. The valve device is in communication with the inside of the housing body. A joined edge portion in which the mutually facing heat-sealable resin layers are fused together is formed in a peripheral edge portion of the housing body. The valve device includes a first portion and a second portion. A valve mechanism configured to reduce the internal pressure of the housing body if the internal pressure is increased due to gas generated in the housing body is formed in the first portion. An air passage configured to guide gas generated in the housing body toward the valve mechanism is formed in the second portion. The first portion is located on an outer side of an edge of the joined edge portion. At least a portion of the second portion is sandwiched between the heat-sealable resin layers in the joined edge portion.
1. A battery comprising:
a battery element;
a housing body that is constituted by at least one laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer layered in that order and houses the battery element; and
a valve device that is in communication with the inside of the housing body,
wherein sections of the heat-sealable resin layer of the at least one laminate face each other in a peripheral edge portion of the housing body,
a joined edge portion in which the mutually facing sections of the heat-sealable resin layer of the at least one laminate are fused together is formed in the peripheral edge portion of the housing body,
the valve device includes:
a first portion in which a valve mechanism is formed, the valve mechanism being configured to reduce an internal pressure of the housing body if the internal pressure is increased due to gas generated in the housing body; and
a second portion in which an air passage is formed, the air passage being configured to guide gas generated in the housing body toward the valve mechanism,
the first portion is located on an outer side of an outer edge of the joined edge portion and is not sandwiched between the sections of the heat-sealable resin layer of the at least one laminate that are fused together in the joined edge portion,
the first portion and the second portion of the valve device are separate from the housing body,
at least a portion of the second portion is sandwiched between the sections of the heat-sealable resin layer of the at least one laminate in the joined edge portion,
in a thickness direction of the battery, a length of the first portion is longer than a length of the second portion,
a step is formed at a boundary between the first portion and the second portion,
the first portion and the second portion are made of different resin materials, and
the resin material of the first portion has a higher melting point than the resin material of the second portion.
2. The battery according to claim 1 ,
wherein a length of the second portion in a width direction of the battery is longer than a length of the second portion in a thickness direction of the battery.
3. The battery according to claim 1 ,
wherein a cross-sectional shape of the air passage is a circular shape.
4. The battery according to claim 1 ,
wherein a length of a cross section of the air passage in a width direction of the battery is longer than a length of the cross section of the air passage in a thickness direction of the battery.
5. The battery according to claim 1 ,
wherein the second portion includes a pillar that is formed in the air passage.
6. The battery according to claim 1 ,
wherein an outer surface of the second portion has a satin finish surface.
7. The battery according to claim 1 ,
wherein a corner of an end part of the second portion on a side opposite to the first portion is rounded in a plan view.
8. The battery according to claim 1 ,
wherein an external shape of a cross section of the second portion with respect to which a center line of the air passage is the normal line is a polygonal shape, and a corner of the polygonal shape is rounded.
9. The battery according to claim 1 ,
wherein a flat surface is formed at least in a portion of an outer surface of at least one of the first portion and the second portion.
10. The battery according to claim 1 ,
wherein an adhesive member that is configured to adhere to both the second portion and the heat-sealable resin layer of the at least one laminate is arranged between an outer peripheral surface of the second portion and the heat-sealable resin layer of the at least one laminate.
11. The battery according to claim 1 ,
wherein a helium leakage amount from a secondary side to a primary side of the valve device measured in an environment at 25° C. in accordance with a method defined in “vacuum spraying method” of JIS Z2331:2006 “Method for helium leak testing” is from 5.0×10 −11 Pa·m 3 /sec to 5.0×10 −6 Pa·m 3 /sec inclusive.
12. The battery according to claim 1 ,
wherein a maximum distortion in a thickness direction of the housing body after gas generated in the housing body is discharged via the valve device to the outside of the housing body is less than 30%.