Development testing of zinc/bromine batteries

The zinc/bromine battery is a relatively high energy density system with the potential for bulk energy storage at a low cost. A new design that uses a thermal welding technique to achieve a hermetically sealed battery stack is described. Electrodes in the design are based on polyethylene, instead of polypropylene, since the latter was more susceptible to expansion and warpage in the presence of bromine. Embedded glass fibers are also used to increase the tensile modulus of the electrodes in the new design. Improved separators and improved electrolyte flow distribution within the battery stack have reduced the amount of self-discharge compared to earlier batteries. Specific properties of the batteries were measured by different kinds of tests in the laboratory. The initial test given to each battery was a set of constant current cycles to determine the fundamental operating characteristics. These test results served as a baseline for comparison after other tests were completed