Abstract: A battery cell bypass protection technology for use with NiH2 (or other energy storage) cells on a spacecraft or other high reliability application. The device is a thermally activated switch, designed to bypass the current around a failed (open) or failing cell so that the other cells in the battery are unaffected. One unique aspect of the design is a “pre-loaded” compression action, solder shorting mechanism. Another unique aspect is that the construction employs series redundant heaters and blocking diodes in multi-chip packages. These unique aspects provide consistent and complete shorting to provide a low-resistance cell bypass in any orientation on earth (1g) or in orbit (0g). Another unique aspect is the use of non-lead-based solder that minimizes “creep” over time and temperature.