Boosting EV range with microwave energy

The method charges the car at an EV charging station, and the charging process stores the microwave energy inside the car.

Man charging car in the snow

The method couples a chemical heat pump with microwave energy, and produces heating or cooling on demand, with much higher energy density than battery packs

Birmingham researchers are working on a novel energy storage system to boost EV driving range during hot or cold weather, 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%1.

The method, invented by Birmingham energy expert Professor Yongliang Li during research into technologies for a zero-carbon future, couples a chemical heat pump with microwave energy, and produces heating or cooling on demand, with much higher energy density than battery packs.

Called e-Thermal bank, the system is a secondary energy source for electric vehicles. It is ‘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.

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.

Professor Yongliang Li, School of Chemical Engineering

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 is Chair in Thermal Energy Engineering in Birmingham’s School of Chemical Engineering. His research focusses on thermal energy processes and systems including thermal energy (heat and cold) storage, refrigeration, air conditioning, carbon capture and storage, process and system simulation and optimisation. Much of his research is supported by the Engineering and Physical Sciences Research Council (EPSRC).

He 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.

Notes for editors

For media information contact Ruth Ashton, University of Birmingham Enterprise, r.c.ashton@bham.ac.uk

Commercial enquiries to Jon Roberts, University of Birmingham Enterprise, j.roberts@bham.ac.uk

The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 8,000 international students from over 150 countries.

University of Birmingham Enterprise helps students and researchers turn their ideas into new services, products and enterprises that meet real-world needs. We also provide incubation and bio-incubation, support innovators and entrepreneurs with mentoring, advice and training, and manage the University’s Academic Consultancy Service. Follow us on LinkedIn and Twitter.

Reference:

  1. AAA Electric Vehicle Range Testing: Proprietary research into the effect of ambient temperature and HVAC use on driving range and MPGe, available at aaa.com/AAA/common/AAR/files/AAA-Electric-Vehicle-Range-Testing-Report.pdf