POWER STORAGE DEVICE

The extraction portion is configured to include a first piece portion extending in a direction orthogonal to the first direction from an outer edge portion provided on an edge of the flat plate portion when viewed from the first direction, a second piece portion extending in the first direction and having an attachment portion that attaches the extraction portion, and a bent portion being where a plate material configuring the extraction portion bends, and connecting the first piece portion and the second piece portion. A spring portion that is configured to relieve a stress acting on the extraction portion is provided between the connection portion to the outer edge portion and the attachment portion in the extraction portion. The spring portion includes at least a first bent portion being where the plate material bends other than at the bent portion.