Battery pack and battery pack manufacturing method

A battery pack comprising:

• a cell group obtained by stacking a plurality of unit cells in a thickness direction, the unit cells each including a cell body having a power generation element and a flat shape, and an electrode tab protruding out from the cell body, and the electrode tabs having distal end portions bent in a stacking direction of the unit cells;
• and
• a flat plate shape bus bar connecting the distal end portions of the electrode tabs of the unit cells while facing the distal end portions, and electrically connecting the electrode tabs of at least two of the unit cells with each other, wherein:
• each of the distal end portions of the electrode tabs of at least two of the unit cells and a surface of the bus bar that faces the unit cells are in contact and welded to each other,
• the distal end portions of the electrode tabs that are electrically connected by the bus bar are bent in a same direction,
• the cell group comprises spacers disposed between the electrode tabs of the unit cells that are stacked, the spacers including supporting portions that abut the electrode tabs from an opposite side of the bus bar to support the distal end portions of the electrode tabs, and
• each of the spacers are attached to a respective one of the unit cells.