Patent attributes
A method for assembling a battery pack having a cell group includes stacking the plurality of the unit cells such that distal end portions of the electrode tabs of the unit cells are bent along a stacking direction, disposing a pair of first cover members both ends of the unit cells in the stacking direction, disposing a pair of second cover members on both ends of the unit cells in a direction that intersects with the stacking direction, welding the first and second cover members while the cell group is pressurized using the first cover members. The welding of the first cover members and the second cover members is performed prior to electrically connecting the unit cells by a bus bar. The method further includes laser-welding the bus bar to distal end portions of the electrode tabs after the first cover members and the second cover members are welded.