Charging a battery quickly generates a lot of heat, with the extra energy capacity of modern and upcoming electric vehicle batteries, extracting this heat becomes more challenging. If this heat is not distributed effectively, not only is the performance and lifetime of the battery greatly reduced, but thermal runaway and vehicle fires are a potential hazard. Immersion cooling is an emerging potential alternative to traditional battery cooling methods and is just one of the topics covered in the Thermal Management for Electric Vehicles 2020-2030 report from IDTechEx.
While most major OEMs in the passenger car market are utilising air or water-glycol cooling methods, some suppliers are turning to new methods to meet the increasing thermal demand on vehicle batteries. This is especially true when considering more specialised markets such as electric construction and mining vehicles, in this scenario extremely intense battery discharge is required and hence a serious amount of heat is generated. Immersion cooling is one of these emerging technologies for battery thermal management and has been previously demonstrated in electronics for data centres, high-performance computing and grid power systems, but is now seeing an opportunity in the electric vehicle market.
As the name suggests, immersion cooling involves submerging the battery cells in a liquid coolant, in doing so superior thermal contact and homogeneity can be achieved. Additionally, the flame-retardant nature of the fluids acts as a safety feature, suppressing thermal runaway events before they propagate between cells. A key consideration here is obviously the choice of coolant fluid used, through primary research, IDTechEx benchmark the current fluid options, including those from 3M, Solvay, M&I Materials and Engineered Fluids. These fluids are all dielectrics but vary in their properties with factors such as weight, thermal conductivity, environmental considerations and cost, being extremely important.