Boosting EV range with microwave energy
25th February 2024
UK: Researchers from the University of Birmingham are working on an energy storage system which couples a chemical heat pump with microwave energy to produce heating or cooling on demand.
Called e-Thermal bank, the system is a secondary energy source for electric vehicles. It can harness electricity to drive a high-density (1600Wh/Kg) thermochemical-based system.
Heating and cooling the EV cabin when using the car’s climate control system can consume a significant amount of electric power, and subsequently reduce the driving range, by as much as 40%.
The method, invented by Birmingham energy expert Professor Yongliang Li, involves the e-Thermal bank being ‘charged’ at the EV charging station by using microwave energy to dissociate a solid-vapour working pair and also condense the vapour into liquid. This charging process stores the microwave energy inside the car in the e-Thermal bank.
During discharging, the process is reversed by feeding the vapour into a reactor to generate heat through an exothermic reaction, while a liquid-gas phase change process in an evaporator generates cooling simultaneously.
Professor Yongliang Li, who is chair in Thermal Energy Engineering in Birmingham’s School of Chemical Engineering, said: “Heating and cooling the EV cabin requires considerable energy and is the most significant contributor to EV range reduction.
“We aimed to offload these thermal management tasks to a microwave driven process. Microwave is a fast heating method, because microwaves penetrate uniformly through materials and so deliver energy evenly into the body of the material. The energy cost can be minimised by coupling with a smart meter to charge the system when energy is cheap, and the stored energy can then be used at any time.”
“We predict that by replacing conventional HVAC and possibly a small portion of the battery pack, e-Thermal banks would provide efficient cabin temperature control and a range extension of up to 70%, at a lower cost than increasing battery capacity.”
University of Birmingham Enterprise has filed a patent application covering the e-Thermal bank system and method for storing energy and is seeking commercial partners for licensing collaboration or co-development.
