A battery pack includes a first battery and a second battery each having a bent part at one side; and an adhesion member interposed between the bent part of the first battery and the bent part of the second battery and adhering the bent part of the first battery to the bent part of the second battery.

A battery module includes a housing and battery cells disposed in the housing, each of the battery cells including two terminals. The battery module also includes bus bar cell interconnects including a first material, where each bus bar cell interconnect is configured to electrically couple two adjacent battery cells via an electrical coupling with a first terminal of one of the adjacent battery cells and a second terminal of the other adjacent battery cell, where at least one of the first and second terminals includes the first material. The battery module includes welds, each weld being disposed at a corresponding welding point to directly couple one of the bus bar cell interconnects with the corresponding at least one terminal including the first material. Each welding point is accessible for welding from a position above the battery cells when the interconnects are disposed over the battery cells.

A polymer battery module packaging sheet includes, as essential components, a base layer (61), an aluminum layer (62), chemical conversion coatings (64a, 64b) coating the opposite surfaces of the aluminum layer (62), and an innermost layer (63). The chemical conversion coatings (64a, 64b) are formed by processing the opposite surfaces of the aluminum layer (62) by a phosphate treatment method. The base layer (61) and the innermost layer (63) are bonded to the chemical conversion coatings (64a, 64b) of the aluminum layer (62) with adhesive layers (65a, 65b), respectively.