BATTERY, HEAT SEALING APPARATUS, AND METHOD OF MANUFACTURING BATTERY

A battery includes a battery element, a housing body, and a valve device. The housing body houses the battery element. The valve device is in communication with the inside of the housing body. Heat-sealable resin layers face each other in a peripheral edge portion of the housing body. A joined edge portion in which the mutually facing heat-sealable resin layers are fused together is formed in the peripheral edge portion of the housing body. The valve device is configured to reduce an internal pressure of the housing body if the internal pressure is increased due to gas generated in the housing body. The valve device includes a first portion that is located on an outer side of an edge of the joined edge portion and a second portion that is sandwiched between the heat-sealable resin layers in the joined edge portion.