IAA: ixetic displays R744 lithium-ion battery cooling for EVs

The German supplier is presenting its innovative CO₂ thermal management system for electric cars at the Frankfurt Motor Show. The system, sparking high interest among battery suppliers, does not only improve the Li-ion battery performance but will also heat the passenger compartment. (+ photo gallery)

After having designed the first R744 (CO₂) compressor for the Mobile Air Conditioning of conventional vehicles, ixetic has taken another step into the future to provide a compact, safe, and highly efficient thermal management solution for electric cars. At a time when automobile experts are convinced that the long term future belongs to electric cars, ixetic’s solution, operating live on the trade show flow, sparked high interest among media and industry experts visiting the International Motor Show in Frankfurt. It solves a fundamental problem carmakers are currently facing: the optimal efficiency and storage capacity of lithium-ion batteries, acknowledged as the best solution for future electric vehicles.

The R744 thermal management system ensures an optimal efficiency and life span of the battery by keeping temperatures always in the required temperature window of 15 to 35°C. At lower temperatures the capacity of the battery is significantly reduced, whereas values higher than 35°C reduce their service life. Even in temperate latitudes temperatures can reach -20°C to +50°C. Moreover, the battery heats up during operation.

Compact and safe solution

These challenges have been solved by an R744 cooling circuit using the compressor also as a heat pump for both heating and cooling. The compressor gets the power directly from the battery, meaning that when the car is parked and the engine is not running, it will still be able to heat and cool. The lithium-ion battery is therefore in the optimal temperature range at all times. The hermetic thermal management solution is heat insulated to ensure the battery is always warm.

Furthermore, during the cold season the electric car can be heated with the same system, hence saving space and optimising the weight and performance of electric vehicles. The high efficiency of the heat pump reduces the loss of driving range from 40% - when the car is heated electrically by a PTC element – to just 10-15%. Electric cars, as opposed to combustion engines, require an additional heating system. This problem is solved by integrating the R744 solution.

Finally, as opposed to proposed chemical flammable solutions not suitable for electric vehicles with a variety of potential ignition sources, the inflammable refrigerant CO₂ poses no threat whatsoever of burning and hence of releasing toxic gases.