Freudenberg Sealing Technologies has developed a seal for Li-ion batteries that not only resists fire but “folds” to offer extra protections. Here’s how it works: fixed aluminum elements are equipped with a sealing profile on their outer edges to not only provide stability but also integrate mounting points for the clips used to attach the seal at the housing cover.

The elements are connected with one another using a continuous sealing profile, which is highly flexible and compensates for small dimensional deviations in the housing. Freudenberg says the installation is extremely reliable, because the foldable seal is a complete component and does not need to be assembled from separate elements.

Also, metallic inlays ensure high electrical conductivity between the battery housing and its cover. This is important for the efficient screening of electromagnetic fields that result from the flow of current in the battery. Otherwise, the fields could disrupt other electronic components in the vehicle.

The company has developed its own endurance tests so it can verify satisfactory operation of the seals. The process makes it possible to test the seals without using real housings, which are hard to handle due to their size.

The testing process uses a hydraulic ram with a frequency of up to 50 Hz to act on a sealed test housing, consisting of two halves, which simulates the aerodynamic torsion that occurs during driving. A slight overpressure is continually maintained inside the housing to detect leaks. The entire test takes place in a climate chamber so the impact of the temperature can be recorded.

“The electric car will prevail,” said Freudenberg VP Paul Hailey. “But manufacturing large batteries in high volumes is a major challenge for our customers. With our sealing solutions, we are going to help them master this.”

Source: Freudenberg Sealing Technologies