Thermal management of batteries for electric vehicles is a crucial issue. It is important not only for safety and thermal runaway prevention, but also for the performance and longevity of the battery. Manufacturers are considering how to get more energy density into the batteries but thermal management is often addressed as an afterthought, considering pack-level solutions when cell design could improve the overall thermal performance and lead to other benefits, such as pack weight reduction.
A new article was recently published by researchers from Imperial College London which covers their previous work on how manufacturers could address cell-level heat dissipation and a new metric for cell thermal performance that could become a new standard in the electric vehicle industry. This new article can be found here.
The academic group have published work in the past, using cell tabs to remove heat from battery cells in a more uniform manner than is currently adopted. This is a promising alternative to surface-based cooling. Current cell designs, however, limit how much heat can be removed by these tabs. More about tab cooling can be seen in this video. The new cell cooling coefficient (CCC) can be used as a standard across the industry for any type of battery cell, giving an objective marker of thermal performance. The researchers suggest this could provide another metric to incite competition between OEMs in proving the thermal performance of their cells. More information on the CCC can be found in the open-access journal here.
Dr Alastair Hales, author of the publication, stated to IDTechEx that, "Lithium-ion batteries get hot, and it is hard to keep them cool. Industry has paid too little attention to this problem for the past decade. The focus has been elsewhere: boosting the amount of energy a single cell can store. Bad thermal management means reduced performance and lifetime in battery packs across the world. To escape this problem, cell manufacturers must consider thermal management during cell design, rather than optimising energy density alone. We propose the Cell Cooling Coefficient as a metric to aid cell design, a tool for cell selection, and a standard to incite competition across the industry."
OEMs have adopted several different strategies for thermal management and components like the electric motors and power electronics in addition to the batteries are important factors to consider. The report from IDTechEx on "Thermal Management for Electric Vehicles 2020-2030" uses primary information and extensive research to detail the methods used by OEMs in these thermal applications in addition to trends, emerging technologies and forecasts through to 2030. IDTechEx has market and technology reports across the electric vehicle market in addition to a wide portfolio of reports in other emerging technologies.