Material and sealing expert Freudenberg Sealing Technologies develops new, particularly compatible elastomer material
Weinheim, April 10, 2025 – With an optimized gasket material, Freudenberg offers an alternative to PFAS-containing thermoplastic and FKM gaskets for use in e-mobility. The new material series is processed by injection molding, offers higher sealing performance, ensures battery life and meets increasing environmental requirements.
In the rapidly expanding electric vehicle market, improved battery performance with shorter charging times, maximum temperature resistance and a longer battery life are key to success. To achieve this, OEMs in Europe and the USA need materials that also comply with stricter national and international environmental regulations. A high-performance material for such applications comes from the elastomer material group. Freudenberg Sealing Technologies has succeeded in developing a material that offers relevant advantages over thermoplastics in the event of a thermal runaway and that takes battery applications in e-mobility to a new level.
Utilizing material advantages – elastomer seals instead of thermoplastics
In the thermoplastics traditionally used for battery seals, the long-chain molecular structure of the macromolecules is not chemically cross-linked with each other, but only connected via weak intermolecular forces. Although thermoplastics can be elastically deformed to a certain extent, they also undergo a functionally relevant amount of plastic deformation during the continuous charging and discharging of the battery cell. Elastomers, whose molecular chains are chemically cross-linked, are different. In their basic state, the polymer chains are in a ball that is pulled or compressed under tensile and compressive loads. Due to their entropy elasticity, these cross-linked materials react elastically and reversibly and retain their shape during the cyclical volume change of the battery cells under load.
“Our O-rings made from the new elastomer therefore prevent electrolyte from leaking out of the battery cell or impurities from entering the cell,” explains David Kuhne, Application Engineer at Freudenberg Sealing Technologies. “You can’t think of a battery cell as a rigid structure – it “breathes”. When the battery cell undergoes a temperature rise from ambient temperature to ranges of – as a rule – up to 60°C, it expands and contracts in equal measure when it cools down. Elastomers have significant advantages over thermoplastics under this continuous load,” he says, illustrating the charging and discharging process.
Material knowledge – From cutting-edge research to large-scale production
When developing new materials for battery applications, the focus is on sustainability as well as economic aspects. In principle, the longer the battery can be used, the more sustainable electric vehicles become. The new sealing material from Freudenberg Sealing Technologies contributes to this. When using the new material in customer projects, the performance-relevant leakage rate of the battery cells was improved by an order of magnitude, i.e. tenfold compared to conventional thermoplastic seals.
Another essential aspect is that the electrochemistry of battery cells is extremely sensitive to potential impurities. Dr. Stefan Schneider, Head of Material Development at the Lead Center O-Rings, explains: ” A premature loss of capacity observed in a cell sealed with conventional elastomers can result from the minimal but nevertheless present contamination of the sealing material. A similar effect has a moisture ingress into the cell, as it can cause the electrolyte components to decompose. These aspects were taken into account in the development of the new material.” In addition, the process engineering department has optimized the manufacturing processes in such a way that these high-performance battery cell seals can be mass-produced.
Rising battery demand – growth impetus for electric vehicles
As a leading supplier of high-performance materials and innovative products, Freudenberg Sealing Technologies is contributing to safe and sustainable e-mobility. Just at the right time: the annual “Global Electric Vehicle Outlook” published by the International Energy Agency (IEA) provides a breakdown of global developments in the field of electromobility. The “Outlook 2024” states that the global electric vehicle fleet will have to grow from under 45 million in 2023 to 250 million vehicles in 2030 in order to remain on the path to net zero emissions. This will also greatly increase the demand for high-performance batteries. Freudenberg Sealing Technologies is also pleased about this: “As a development partner for customer-specific projects, we contribute many years of expertise in materials and innovation. Thanks to our advanced analysis and vertically integrated manufacturing processes, we can develop and implement very agile, competitive production processes,” summarizes David Kuhne.
Source: Press release from April 10, 2025
