A battery module comprises a battery element and a storage unit configured to contain the battery element therein. The storage unit comprises an electrically conductive positive electrode-side plate and an electrically conductive negative electrode-side plate. The positive electrode-side plate and the negative electrode-side plate define a storage space to contain the battery element therein. The storage unit has a joint end provided on the periphery of the storage space and formed by joining an outer peripheral area of the positive electrode-side plate with an outer peripheral areal of the negative electrode-side plate across an insulating sheet placed between the two outer peripheral areas. The joint end comprises: a wind part formed by stacking and winding the two outer peripheral areas to be pressure-bonded to and joined with each other; and an outer peripheral frame body formed by insert molding using an insulating resin to surround the wind part.