Battery pack

The utility model relates to an energy storage device technical field especially relates to a battery pack, and it includes: the plastic width -lock type single -layer sealed packing case comprises acasin. Battery module, battery module are installed in the box, and the battery module includes the end plate, coupling mechanism, coupling mechanism include connecting rod, movable block, mounting and elasticity pre -tightening piece, and the one end of connecting rod is articulated with the end plate, and the other end is articulated with the movable block, and the mounting is connected in the box, movable block activity suit in mounting, and elasticity pre -tightening piece suit in mounting, and elasticity pre -tightening piece lies in between the head and movable block of mounting. When the battery took place the inflation, this bulging force passed through the end plate, the connecting rod transmits to the movable block, moved for the mounting through the movable block, can absorb thebulging force of battery.