General Motors has introduced a patented energy recovery system for the Ultium electric car platform. It uses the heat generated by the batteries, power electronics and other drive components, but goes beyond the mere function of a heat pump.
With the utilised waste heat, the system can – like a heat pump – warm the interior and increase the range by about ten per cent, according to GM. The “waste energy” can be used to reduce the energy needed for heating, which must be taken from the battery.
The system can also capture and use moisture inside and outside the vehicle, including passenger body heat, according to GM. How exactly this works, however, is not clear from the announcement. As a result, the system is said to be able to heat the interior more quickly in cold weather than comparable systems in vehicles with internal combustion engines.
The “Ultium Energy Recovery” can not only heat the interior, but also the battery. Thus, no or less energy from the battery has to be used to precondition it before fast charging – the system uses the waste heat from the engines and electronics. On the other hand, the energy recovery can also pre-cool the drive system, for example in order to use the “Watts for Freedom” function in the GMC Hummer EV – i.e. maximum acceleration.
“Having a ground-up EV architecture gives us the freedom to build in standard features like Ultium’s energy recovery capabilities,” says Doug Parks, GM executive vice president, global product development, purchasing and supply chain. “This helps us squeeze more efficiency, performance and overall customer benefit out of our EVs.”