Silent Cooling Technologies for Fast Charging of Electric Vehicles

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.

Future electric vehicles will be charged much faster than today. Even during longer trips recharging your car has to be fast and convenient. Technically this creates more heat to be dissipated within a short amount 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) are 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.

• 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. (8-10% lost as heat)
• 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 heatflux to ambient air must also be implemented by the system.

• Both early stage solutions and mature solutions, mature solutions > TRL 5 are preferred (Integrated components demonstrated in a laboratory environment)
• Technologies may refer to, but are not limited to:
  • magnetochaloric 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

• Passive cooling technologies requiring high temperature gradients between battery surface and ambient temperature
• Technologies harmful to the environment
• Technologies with high service and maintenance requirements

To submit your idea or proposal, please use the Respond button on the right of this page. Please note that only non-confidential information can be accepted. By submitting a response: you represent that the response does not contain and will not be deemed to contain any confidential information of any kind; and you acknowledge that BMW may, in their absolute discretion, select or reject a response or any portion thereof.

Your response should be an executive summary of what you are proposing. It should include both technical information on how the technology will work in addition to the given benefits to the consumer and how you believe it can be of use to us as a business. Information on the background of those involved in the project will also be required in your response to this need posting.

We suggest you include the following:

• Describe the technology
• How the technology is relevant to our brands (specific or in general)
• Level of maturity of the technology (development stage or just a proposal)
• How adaptable is the technology, can it be used in a wide range of scenarios?
• Background information on the people involved in the proposal

Remember….. Don’t send anything that could be considered confidential at this point.

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