POWER STORAGE ASSEMBLY AND GASKET

A power storage assembly having a gasket containing a copolymer containing a tetrafluoroethylene unit and a fluoro(alkyl vinyl ether) unit, wherein the copolymer has a content of the fluoro(alkyl vinyl ether) unit of 2.0 to 6.0% by mass with respect to the whole of the monomer units, a melt flow rate of 0.5 to 55 g/10 min, and the number of functional groups of 50 or less per 10main-chain carbon atoms.