The present invention relates to a bipolar battery, especially a NiMH battery, having: a sealed housing, a negative end terminal, a positive end terminal, and at least one biplate assembly comprising a biplate, a positive and a negative electrode. A separator is arranged between each negative and positive electrode forming a battery cell, said separator includes an electrolyte. An inner barrier of a hydrophobic material is arranged around at least one electrode, whereby said inner barrier prevents an electrolyte path from one cell to another cell, and a frame is present to provide predetermined cell spacing between each biplate and/or biplate and end terminal. The frame is attached in such a way to each biplate to permit ambient gas to pass between adjacent cells, thereby creating a common gas space for all cells in the battery. The invention also relates to a method for manufacturing a bipolar battery.