Freudenberg Sealing Technologies has developed Cell Caps 2, a next-generation battery cell cap technology for prismatic and cylindrical cells.
The company is presenting the technology at Battery Show Europe in Stuttgart alongside expanded cell-to-cell barriers, venting foam mats, a busbar seal demonstrator, and previews of advanced battery cooling and heat pump components. The portfolio is aimed at automotive and general industrial battery systems, including EV platforms and stationary energy storage.
Battery cell caps occupy limited space inside the cell, but they carry several safety and manufacturing functions. They must seal the cell chemistry from the environment, support electrolyte filling, provide electrical insulation, contribute to mechanical integrity, and help manage safety requirements during fast charging or thermal runaway events.
Cell Caps 2 integrates the terminal in moulded rubber into the base plate of the cap. Liquid elastomer is injected into the gap between the poles and the cap base plate, bonding the components together to provide gas tightness, mechanical robustness, and electrical insulation. Freudenberg says the approach reduces the number of parts and mass, which can contribute to lower overall battery weight.
The company is also working on mass production of a round cell cap using the next-generation technology. Its manufacturing route draws on processes used for valve stem seals, a component Freudenberg already produces in very high volumes. Battery innovation often turns on this kind of industrial transfer, where a proven production method is adapted to a newer, more demanding application.
Cell caps are small components within the battery system, but their role is structurally and operationally significant. EV battery design is being shaped by the need to raise energy density, improve safety, control cost, and simplify assembly. Components that reduce part count, save space, or combine multiple functions can have a cumulative effect across high-volume packs.
Battery systems leave little room for weak links. Sealing, venting, thermal barriers, electrical insulation, and mechanical tolerance must all function under vibration, temperature cycling, charge and discharge stress, and ageing. A cell cap that performs well in isolation still has to integrate with welding, filling, formation, inspection, module assembly, and pack-level safety systems.
Freudenberg’s wider battery display reflects that systems view. The company’s expanded cell-to-cell barriers are available in additional thicknesses and material variants, including multi-layer structures with foam or elastomer compression layers and UL94-V0-certified heat shields with adhesive tape. These barriers can be adapted for thermal resistance, mechanical stability, cell swelling, and chemistries including NMC, LFP, and emerging formulations.
The venting foam mats are positioned above cells to help protect neighbouring cells during thermal runaway events. The busbar seal demonstrator shows how seals can compensate for thermally induced length changes while maintaining protection against media and the environment. As pack designs become more compact, thermal and mechanical interactions between cells, busbars, cooling systems, and housing structures become harder to manage.
The EV market is also putting more pressure on component-level industrialisation. Carmakers and battery suppliers are working to reduce cost while maintaining safety and performance, particularly as demand growth becomes more uneven between regions and vehicle segments. Components that can be industrialised across multiple cell formats and chemistries help suppliers spread development cost and improve manufacturing scale.
Stationary energy storage adds another route to volume. Industrial and residential storage systems may use different duty cycles and cost structures from EVs, but they share many safety and manufacturing requirements. Sealing, insulation, and thermal protection technologies that can be adapted across vehicle and energy storage markets give suppliers a stronger platform for long-term development.
Freudenberg’s Cell Caps 2 development shows how battery progress is moving into the less visible parts of the system. Chemistry, range, and charging speed tend to dominate public attention, but industrial progress often sits in seals, barriers, vents, cooling plates, connectors, and production processes. Those components determine whether battery designs can move from technical promise to reliable manufacture.
