Thermal Runaway in Batteries

Thermal Runaway in batteries is a condition in which the internal temperature of the battery increases.  This causes the charging current to increase.  This, in turn, causes the temperature to increase.  This again leads to the charging current increasing.  Thus, a vicious cycle is created.

Thermal Runaway ultimately leads to battery failure.  In some cases, it can even cause explosions.

Thermal Runaway occurs mostly when the battery is in the float charging mode.  The usual causes are high ambient temperature in the location where the battery is placed.  This causes the battery to heat up.  During charging, heat is produced inside the battery.  This heat has to be dissipated.  Hence, adequate ventilation should be provided to the battery.

The charging current should be monitored periodically.