Driven by the need to electrify, the automotive sector is now focused on creating highly efficient, power dense and lightweight electric motors, batteries and power electronics – and thermal management is now the key challenge to overcome in unlocking maximum performance.
We believe that over the next 5-10 years, direct liquid immersion cooling of electric motors, batteries and power electronics will become increasingly important as forced air cooling and indirect liquid cooling will not continue to meet the high performance needs of the market.
For high performance and demanding applications, esters will be key in helping formulators tune their cooling fluids to the specific requirements of the electric vehicle.
Exposing batteries to extremes of temperature - high and low - can result in unwanted effects. In the case of low temperature operation, battery performance will suffer, whilst at high temperatures the battery is at risk of overheating with the potential to enter into a dangerous thermal run away event.
Hence, battery pack designers need to create systems that can keep temperatures consistent to optimise for both performance and safety. This is no trivial task, as the battery will be exposed to variations of external temperature and usage patterns – for example, battery demand will vary hugely when comparing driving and high power fast charging events.
As such, automotive OEMs such as Tesla, Audi and BMW have started to use in-direct liquid cooling to overcome thermal management challenges and to protect the battery pack. But as power densities continue to increase, cooling needs will too, which will lead to more novel and improved cooling architectures and designs.
Improved cooling beyond in-direct liquid cooling is only possible with non-conductive dielectric cooling fluids. These fluids are able to come into direct contact with heat generating components, providing superior heat removal compared to forced-air and indirect-liquid cooling. This is because cooling liquids have higher specific heat capacities compared to air, whilst direct immersion cooling removes low thermally conductive interface materials that are used in in-direct cooling designs.
The optimum fluid for immersion cooling must not degrade in the system, it must be non-conductive, have very low viscosity and must have excellent thermal removal properties such as high thermal conductivities and specific heat capacities. It is likely that in the future – in line with existing EcoLabel legislation - these fluids will also be biodegradable, as to not contaminate the environment in the event of a leak.
At Croda, our high performance, high purity esters have superior properties versus other single-phase-liquid fluids and can be blended with other cooling fluids to provide thermal performance, material compatibility and safety benefits to fully formulated coolants.
As experts in the design, synthesis and manufacture of esters, we can create bespoke chemistry designed for the emerging needs of formulators looking to meet immersion cooling needs of the market – contact us to speak to our technical team about your requirements.
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