A sealed rechargeable battery includes: a metal case having an elliptical
or rectangular cross section; a metal sealing plate for sealing an
opening at one end of the case; and an electrode plate assembly being
housed in the case with an electrolyte solution. In this configuration, a
plurality of projecting ridges are formed in a continuous or
discontinuous manner on both longer side faces of the case between a
bottom face and the opening so as to enhance the cooling performance and
to improve the strength of the side faces of the case.