Prevention of thermal runaway in VRLA batteries

Abstract

This paper presents a user's perspective on the thermal runaway phenomenon and discusses a multi-faceted approach to dealing with this condition. It does not attempt to analyze the physics within the thermal runaway process and does not present any new insights into the phenomenon. Rather, it examines the triggers of the phenomenon and presents methods to either prevent the trigger conditions from occurring or initiate corrective action before the event reaches catastrophic proportions. The recommended arrangement combines packaging techniques, battery float voltage compensation and high voltage limiting, battery string voltage and temperature monitoring and alarm generation. The overall combination provides a cost-effective, reliable and relatively straightforward solution that allows use of VRLA batteries in an extreme environment application without the need for frequent maintenance and with negligible chance for damage from the thermal runaway phenomenon.