Abstract: A lead acid bipolar battery comprises a plurality of bipolar electrodes stacked between two monopolar end collectors in turn closed by end plates. All electrodes have respective plastic stiffening edge frames. The spacer frames are interposed between the electrodes to support the electrode frames. The spacer frames contain electrolyte supporting material and have electrolyte inlet bores and gas outlets. The stack is surrounded by a layer of eventually strengthened polyolefin material which seals the stack and provides a housing for the battery.

Abstract: The method of forming the battery electrode includes providing two complementary half-frames of plastic material each having a substantially flat face delimited by an outer closed line and an inner closed line, where the inner and outer closed lines enclose the perimeter of the plate. Next, a plate is placed within a pressure forming mold between the two half-frames so as to enclose the perimeter of the plate between the outer closed lines and the inner closed lines. Then the mold is closed and heated to a temperature causing the plastic material of the half-frames to fuse and adhere continuously along the entire perimeter of the plate.