Immersive Evaporative Cooling
Common methods for cooling lithium-ion battery systems are using either forced air or liquid convective cooling through heat transfer onto cold plates. These are required to reduce the effects of degradation that temperature can have on the lithium-ion chemistry and prevent dangerous thermal runaway conditions.
However, given the fact that ideal temperatures for lithium-ion batteries can be close to ambient temperatures and that batteries can be spread over large volumes, this does not leave much room for temperature gradients to be driving the heat transfer process.
By using the latent heat and isothermal nature of evaporation, heat can be removed directly from battery cells whilst minimising the temperature difference across a large format battery pack application.
This has numerous advantages in improving the heat transfer density, temperature uniformity and the prevention potential of thermal runaway conditions.
Vantage Power has developed a fully immersive evaporative cooling concept using low boiling point fluids for an automotive cylindrical cell application. The video to the right shows bubbles of evaporated fluid being pumped out of the module.