The document discusses using thermocouples to convert the waste heat generated by laptops into electrical energy to charge the laptop battery. A thermocouple consists of two different metals that produce small amounts of electricity when heated due to temperature differences. Arrays of many thermocouples, called thermopiles, can produce higher voltages and currents. The document proposes installing a thermopile on the bottom of laptops to capture the heat and use it to self-charge the battery, providing energy savings and reducing laptop heating problems.