The market share of battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) is reporting constant growth. As demand has risen over the last several years, the requirements for ever greater ranges, performance, and fast-charging options have grown as well, which can only be implemented by means of battery concepts with higher and higher power densities, e.g. with lithium battery cells. 

The increased heat generated in the batteries as a result requires sophisticated thermal management, which for safety reasons means prioritizing battery cooling more and more. The optimal temperature range for a lithium battery cell is between 15°C and 35°C. Outside of this temperature interval, unwanted side reactions can occur due to the temperature, which significantly reduces the service life of the cells (battery degradation).

Indirect cooling

With indirect cooling, water-glycol mixtures are used as coolants for the battery, which is cooled by cooling plates as the coolant runs through the plates. When ambient temperatures and cooling performance are low, the heat can be discharged into the ambient air. When ambient temperatures are high, the heat can no longer be discharged into the air, but must be transferred to a coolant circuit.
 

Direct cooling (immersion cooling)

The idea behind immersion cooling (also known as liquid submersion cooling) is to put the electric components that need to be cooled in direct contact with a dielectric thermofluid. The battery cells are bathed directly by the electrically non-conducting/insulating fluid, which results in lower, homogeneous cell temperatures.

Our lab has extensive research and development infrastructure, as well as highly qualified experts who are capable of developing dielectric fluids for a number of applications, whether it be immersion cooling for batteries in electric cars, IT hardware, or electric components in other sectors.