ELECTRICITY STORAGE DEVICE

摘要

In the present invention, an electrode assembly of a secondary cell is constructed by laminating electrode-accommodating separators, each accommodating therein a positive electrode, and negative electrodes. A case has rectangular long sidewalls facing flat surfaces of the electrode assembly. Also, the elongation rate of the electrode-accommodating separators varies in different directions, wherein the elongation rate is higher in one direction than in the other directions. The electrode-accommodating separators are arranged with the direction with the high elongation rate being aligned with the direction in which the long side of the long sidewalls extends.