region 112 a that extends between the current collecting protrusions 163 and 167 to form a welding line 180 on the current collecting plate 160 the current collecting plate 160 and the windings of the positive uncoated region 112 a are disposed in the same plane as the welding line 180 the welding is performed between the extensions 163 b and 167 b and the windings of the positive uncoated region 112 a arranged in the same plane in parallel if the windings of the positive uncoated region 112 a and the anode current collecting plate 160 are disposed in the same plane as in the present exemplary embodiment the current collecting plate 160 can be stably welded to the windings of the positive uncoated region 112 a even though the thickness of the current collecting plate 160 is made to be large conventionally a laser is radiated to the current collecting plate and the heat transferred from the current collecting plate is used to weld the windings of the uncoated region therefore if the current collecting plate is made too thick the heat is not properly transferred from the current collecting plate to the windings of the uncoated region if the windings of the positive uncoated region 112 a are protruded between the current collecting protrusions 163 and 167 as in the present exemplary embodiment the laser can be directly radiated onto the windings of the positive uncoated region 112 a to melt the windings of the positive uncoated region 112 a therefore the current collecting plate 160 can be stably welded even though the current collecting plate.