BATTERY PACK

[Problem] To provide a battery pack in which electrode tabs and bus bars can be suitably laser-welded by preventing the laser from penetrating the electrode tabs even if the laser output is increased in order to improve the welding quality.[Solution] A battery pack 100 comprises unit cells 110 which have a cell body 110H that includes a power-generating element 111 and is formed in a flat shape, and an electrode tab 112 extends out from the cell body, and which are stacked in the thickness direction of the cell body; a bus bar 132 electrically connected to the electrode tab by laser welding; and a plate portion 112g that forms a stacked structure together with the electrode tab along an irradiation direction of the laser.