DETECTING CELL OVER-TEMPERATURE IN A BATTERY CELL

A device for indicating over-temperature of one or more battery cells includes a thermal sensor proximate to a battery cell, a controller in electrical communication with the thermal sensor, and a switch and resistor connected in series across the battery cell, which are controlled by the controller. The device detects whether a given battery cell or group of cells reaches a temperature over a threshold temperature. When the threshold is exceeded, the device causes the battery cell to exhibit a duty cycle of voltage change across the terminals of the battery cell. A battery management system (BMS) monitors the voltage of the battery cell and detects the duty cycle as an indication that a temperature fault in the form of a temperature over a threshold temperature has occurred.