Battery systems including battery cells and hydrogen-permeable membranes are provided. In one example, a battery system includes a battery cell. The battery cell includes a cell enclosure disposed about a cell interior. At least one multi-layer stack is disposed in the cell interior and includes a cathode, an anode and a separator disposed therebetween. A hydrogen-permeable membrane is in fluid communication with the cell interior and is configured to selectively allow any hydrogen produced in the battery cell to pass from the cell interior through the hydrogen-permeable membrane to outside of the battery cell while substantially preventing other fluids from passing through the hydrogen-permeable membrane.