The present invention relates to a casing 10 for a sealed bipolar battery 20, 30, 50, 55, 60 comprising at least one battery cell 21, wherein each cell have electrodes with non-metallic substrates. The casing comprises at least two parts, an upper part 12, 31, 41, 61 and a lower part 11, 51, 62, that are joined together to form the casing of the battery. A mechanically compliant arrangement are built-in to the casing to reduce the forces on the cell stack caused by changes in cell thickness during operation, and a pressure means are built-in to the casing to distribute the pressure across the cell stack.