Lead researcher, WMG’s Professor James Marco. Source: University of Warwick

Researchers from the Warwick Manufacturing Group (WMG) at the University of Warwick, U.K., are attempting to find new life for used electric vehicle (EV) battery systems as small energy storage systems (ESS) for powering off-grid regions in developing countries.

The research team repurposed battery units with approximately 2 kWh of energy capacity each, which can be used to power a small shop, several residential homes or a farm, for instance.

Significant byproducts of the growing EV trend are degraded batteries. This is largely due to the fact that EV batteries will reach the end of their useful life without being entirely depleted. According to Professor James Marco, who was lead researcher on the project, the EV batteries reach their end of life when they drop to 80% storage compared to a new battery. While this is not enough energy to power the vehicles, it is still useful for static applications.

The researchers had to first overcome a host of challenges associated with reliability, sustainability and cost. For example, the team had to determine how to protect lithium-ion cells from both discharge and overcharge. The team also had to determine if the ESS prototype could be made compatible with a host of other used battery cells and modules from other battery producers. The team investigated methods for keeping the process low-cost and easy to maintain, while simultaneously offering an easy-to-use interface.

University of Warwick researchers worked in collaboration with Jaguar Land Rover, who supplied the batteries and components from the Jaguar I-Pace, the first all-electric performance SUV. Together, researchers constructed a new battery management system (BMS) and packaging, creating a portable ESS prototype that includes: standard low-cost components for control, safety and communication functions sourced from the Jaguar Land Rover service department, as well as from low-cost electrical retailers; modules that are interchangeable with the second-life system without having to recalibrate the entire BMS; energy to power a small shop, numerous residential homes or a farm; the ability to charge the second-life module using reclaimed laptop chargers; and a simple, easy-to-use and to deploy control system.

“This is a great result that not only provides a highly efficient repurposing solution for automotive batteries but which could also change lives in remote communities. We are now looking for support to allow these new units to be further developed and tested in remote or off grid locations,” concluded Professor Marco.