As battery packs increase in size for use in EV and other high energy applications, hazards of thermal runaway leading to fire or explosion, are becoming more serious than in the past. The only question is how the safe envelope of temperature and charging/discharging rates can be specified and then separately how information for the thermal management system which controls temperature can be properly defined.
Thermal runaway safety tests of this type need to be performed in a custom built adiabatic calorimeter so that first of all the results represent an acceptable but in the worst case scenario and secondly that the thermal runaway which is produced in the laboratory can be handled safely . The Battery Testing Calorimeter (BTC) discussed here, is an ARC-type adiabatic device and does both of these benefits while testing large battery packs.
Tests that seem to be similar can be performed without a BTC for example a battery pack can be heated until the sample is seen to smoke or catch fire for example. Unfortunately the temperature at which this is observed will be much higher than the real value because of heat from the battery. For the same reason, severity of the incident will be understated &ndash the runway under adiabatic conditions will typically start and lower temperature and produce more severe consequences.