BMW is seeking alternative cooling technologies for vehicle batteries to further improve peak cooling capacity during fast charging while reducing cooling components’ vibration and noise emission.

Solutions that meet the need criteria will be invited to work with BMW to evaluate and develop the idea.

Faster charging creates more heat to be dissipated within a short period of time. Current technologies use electric refrigerant compressors.

Rising cooling capacities would generate significantly higher vibrations through fans and other moving components. The thus generated acoustic emissions during faster charging would need sophisticated damping measures to allow pleasant circumstances for people and the surrounding environment.

For example, if you are having a conversation in a charging car, noise above 25 dB(A) is considered uncomfortable. If you are standing close to a charging car, noise from the HVAC System including the radiator above 35 dB(A) is perceived as discomfort.

BMW is, therefore, looking for innovative cooling technologies for fast charging applications that can cope with heat dissipation without exceeding current noise levels while operating. Among the key success criteria:

• Cooling technology working with temperature gradients between battery surface and ambient temperature, operating temperature range -20 °C to +45 °C.

• Scalable for future battery capacities and heat dissipation. As a starting point for the challenge, solutions should assume needing a cooling power > 20 kW during the fast charging with 200-300 kW.

• Low noise production, not beyond 35 dB(A).

• Power density: realizable thermal performance compared to the component volume.

• Peak cooling performance is not required 24/7. Instead the proposed solution has to operate only within the limited time period of fast charging.

• The vehicle will not be moving while charging, so there is no circulating air for cooling available. The heat flux to ambient air must also be implemented by the system.

BMW will consider early-stage as well as mature solutions, although mature solutions > TRL 5 are preferred (Integrated components demonstrated in a laboratory environment). Technologies may refer to, but are not limited to:

• Magnetocaloric technologies
• Electrochemical cooling
• Schukey machine applications
• Thermoacoustic cooling
• Absorption cooling
• The use of phase change materials (vapor cooling)
• Innovative compression methods
• Cooling medium is not specified

BMW will not consider passsive cooling technologies requiring high temperature gradients between battery surface and ambient temperature, technologies harmful to the environment, or technologies with high service and maintenance requirements.

Applicants should apply through NineSights.