An electrode laminate is located in a case. The electrode laminate has opposed first and second principal surfaces and opposed first and second lateral side surfaces. The electrode laminate includes a positive electrode having a planar main surface and first and second opposed lateral ends located on opposite lateral sides of its main surface, a negative electrode having a planar main surface and first and second opposed lateral ends located on opposite lateral sides of its main surface, the main surface of the positive electrode opposing the main surface of the negative electrode. A separator is located between the opposed main surfaces of the positive and negative electrodes and has first and second lateral ends extending laterally outward from the first and second lateral ends of the positive and negative electrodes, respectively. At least a tip of the first and second lateral ends of the separator are bent in a direction towards the first principal surface of the electrode laminate. An electrolyte is impregnated in the separator.