BATTERY PACK

A battery pack includes a retaining member disposed between an adjacent pair of cells and including a retainer retaining a spring, and a pair of tension plates each spanning between pairs of opposing edge faces of a first end plate and a second end plate in a stretched state. The retaining member includes protruding portions protruding from the cells. The protruding portions include respective grooves in which opposing side edges of each of the pair of tension plates are fitted. The side edges of each of the pair of tension plates are fitted in the respective grooves of the retaining member.