Many electrical storage batteries will not deliver their full power at cold temperatures. A large manufacturer of emergency lighting systems was awarded a contract to develop a line of lights that would be installed in an unheated parking garage. If the electricity to the garage failed, then a battery back up system would turn on and power each light. The specification required that the system operate at minus forty degrees F in the event of a power failure. The specification also required that the heating element withstand chemical damage from any battery leakage. Because the battery case was plastic the heating element was required to keep the battery warm without melting the case.

thermo designed a low watt density polymer thick film heating element utilizing its PTC (positive temperature coefficient) technology. This patented technology decreases the heater wattage output as the temperature increases, providing an additional safety factor. With a pressure sensitive adhesive backing, the heating element was easily and reliably adhered to the entire side of the battery to maximize heat trans-fer without case damage. The superior economic advantages of polymer thick film over more traditional battery heating elements increased the customer’s profitability and yet still met
all performance requirements.