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Freudenberg Sealing Technologies triples production capacity for DIAvent pressure compensation element for EV batteries in Germany and the US

The pressure compensation element DIAvent HighFlow (earlier post) enhances the safety of electric car batteries and is generating considerable interest from the automotive industry. Substantial increases in order volumes have come particularly from one Asian and one US automotive group.


At a time when suppliers are fiercely competing for every order, we have successfully secured this and other major orders for our DIAvent product family. We are particularly thrilled about a series production order from the USA, which is unprecedented in DIAvent’s brief history. In order to meet this huge demand, we have rapidly tripled our production capacities.

—Ralf Schmid, Senior Vice President Special Sealing Division at Freudenberg Sealing Technologies

The first fully automated high-tech production cell for DIAvent HighFlow was launched in Reichelsheim, Germany, at the beginning of 2023. A structurally identical twin followed in December in the same production hall. Due to space constraints at the location, a third DIAvent production line will be operational at a facility in Berlin in the first half of 2024.

Freudenberg Sealing Technologies will start up at least one additional production line in early 2025 at its North American site in Shelbyville, Indiana, to fulfill the large US order.

Since 2017, Freudenberg Sealing Technologies has been developing the DIAvent family, an array of intelligent pressure compensation elements that merge pressure equalization and emergency degassing into a single unit, thereby enhancing electric vehicle battery safety. The range extends from the basic DIAvent light ventilation element to the DIAvent HighFlow, which integrates bidirectional pressure compensation with an emergency degassing function in one component.

DIAvent HighFlow is the only product of its kind in the industry. Freudenberg engineers developed it to balance air pressure variations within the battery housing of an electric vehicle and to provide emergency degassing in case of thermal runaway.

The component occupies 50 to 70 percent less space than similar solutions and is lighter due to its innovative UL94-V0-compliant plastic housing. This not only makes it more cost-effective than two separate units but also simplifies installation and reduces supply chain complexity. Moreover, it supports the use of batteries with higher power density, fulfilling the demands for range, performance, and safety in battery-powered vehicles.

The production process encompasses various controls to maintain the consistent high quality of each DIAvent unit. For instance, the opening pressure and tightness of the diaphragm responsible for emergency degassing are automatically tested. The system also verifies the correct air flow rate of the breathable and waterproof e-PTFE fleece disk, ensuring proper ventilation of the battery during regular operation.

Each part must undergo these kinds of tests and various 360-degree camera inspections to receive a laser engraving as a seal of quality. This documents the functionality and at the same time makes it possible to trace each individual pressure compensation element.

Freudenberg Sealing Technologies is also investing in the continued development of the DIAvent product family. For example, customized modifications to the battery housing’s fastening mechanism are being developed based on the technical foundation of the DIAvent HighFlow.


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