Automotive Thermoelectric Generators (ATEG) are devices that utilize the Seebeck effect to recover lost heat in an internal combustion engine powered vehicle. A typical ATEG consists of four main elements: A hot-side heat exchanger, a cold-side heat exchanger, thermoelectric materials, and compression assembly system. Automotive Thermoelectric Generators can be classified according to their hot-side heat exchanger to exhaust-based ATEGs and coolant-based ATEGs. The first type converts the heat lost in the IC engine exhaust, while the second type converts the heat lost in the engine coolant, into electricity.

In Automotive Thermoelectric Generators, thermoelectric materials are packed between the hot-side and the cold-side heat exchangers. The temperature difference between the two surfaces of the thermoelectric module generates electricity. The compression assembly system aims to decrease the thermal contact resistance between the thermoelectric module and the heat exchanger surfaces. In exhaust-based ATEGs, the cold side heat exchanger uses engine coolant as the cooling fluid, while in coolant-based ATEGs, the cold-side heat exchanger uses ambient air as the cooling fluid.