Electric cars are getting longer and longer ranges thanks to high-performance batteries. Manufacturers are packing battery cells ever more tightly to achieve this, leading to higher energy densities in battery housings. They in turn are becoming lighter, more pressure-sensitive and thinner-walled. These sensitive housings require systems that reliably equalize pressure in two scenarios: during regular operations, including driving at different elevations; and during emergencies such as thermal runaway, when the buildup of gas and pressure must be rapidly vented.
Freudenberg has developed the DIAvent® Highflow pressure equalization element specifically for battery systems with higher energy densities. The higher energy density also results in larger gas volumes that need to be dissipated quickly in case of an emergency.
DIAvent® Highflow is primarily designed for use in lithium-ion batteries in larger vehicles with very high energy densities and has four times the mass flow rate of the standard DIAvent® in case of an emergency.
To be able to achieve this in an emergency, the opening created by the sealing lip has not only been enlarged, but additional exhaust ducts have also been integrated.
During normal driving, “respirating” layers of nonwovens in the umbrella valve regulate the exchange of air and pressure. They also keep water and dirt out. In an emergency or accident, a sealing lip allows the escape of large quantities of gas. Its special silicone elastomer responds precisely to predetermined pressure differences. Once the gas escapes, the elastic sealing lip springs back and closes the housing. Short-term pressure peaks can also be cushioned in this way.
Benefits of DIAvent Highflow
- Versatile functions in a single component
- Resealing increases safety after emergency degassing
- More robust than conventional solutions made of porous PTFE film
- Torx wrench installation
