Lithium-ion battery pack for 2011 Chevrolet Volt
Battery cooling is an area of contension in electric cars.
Some, like Nissan, avoid using a coolant fluid with the batteries on the Leaf, as it reduces costs. Others, like Tesla, use cooling and thermal management to ensure the pack stays in its optimum operating range--beneficial for performance, longevity and range.
A new coolant in development in Germany, mixing water with paraffin, aims to improve the cooling process. The scientists developing the coolant claim it's more effective in high temperatures than air or water alone. Effective cooling will be even more important as batteries with greater range are developed.
According to Chemistry World, the solid paraffin droplets used in the solution work on the latent heat principal. As the heat of the battery pack increases, paraffin in the coolant absorbs the heat, melting as it does so and preventing the pack from getting too hot.
When the car is then parked, the paraffin cools, radiating the stored heat and turning back into solid droplets.
The warming and cooling of the fluid ensures the pack doesn't heat up too rapidly, which can cause damage and reduce the battery life.
While the solution works in the lab, it's not yet been tested with an actual battery, so that's the next stage. Tobias Kappels of the Fraunhofer Institute for Environmental, Safety and Energy Technology, explains, "The greatest challenges are to adopt batteries for use with cooling fluids and to optimise the cooling cycle."
The team hopes to have the coolant ready for market use by the end of this year.