With Cell Caps 2, Freudenberg Sealing Technologies is developing the next generation of battery cell caps for prismatic and cylindrical cells. The company will present the technology at Battery Show Europe in Stuttgart from June 9 to 11, 2026. Along with expanded cell-to-cell barriers, venting foam mats, and a preview of advanced battery cooling and heat pump components, it is one of the new Freudenberg product highlights. In addition, a demonstrator illustrates how busbar seals are made robust against damage from thermal expansion while ensuring a reliable sealing function.
Cell caps occupy a considerable portion of the cell volume – space that both the manufacturer and the customer would ideally prefer to utilize for energy storage to power the application. Yet, the function of the cell cap is undeniably demanding: it must reliably seal the cell chemistry off from the environment while simultaneously enabling the safe and reliable filling of the cell with electrolyte. Furthermore, cell caps must facilitate fast charging, incorporate safety mechanisms in the event of thermal runaway, and contribute significantly to the mechanical integrity of the cell.
Cell Caps 2: Fewer parts, more energy
As series production of the Cell Caps Generation 1 ramps up, the next evolution is already underway with Cell Caps 2. The core of the new development consists of integrating the terminal in molded rubber into the base plate of the cell cap:
To fix the terminals within the cell cap, liquid elastomer is injected into the gap between the poles and the cap base plate. The elastomer permanently bonds these components together, providing excellent gas tightness, mechanical robustness, and electrical insulation – all with a minimal number of parts and very low mass, which can significantly reduce the overall battery weight.
In addition to being less complex and more compact, Generation 2 technology can reduce the height of the cell cap by up to 30%, depending on customer requirements. An advantage that directly translates into higher energy capacity and, consequently, a longer operating time.
Freudenberg is currently working on the mass production of a round cell cap that fully leverages all the advantages of the next generation technology. In this context, the manufacturing process for these small components plays a particularly crucial role in optimizing production costs. The cell caps can be manufactured using the same technology as valve stem seals, which Freudenberg produces in the millions with high quality.
Expanded safety portfolio: Thermal barriers and venting foam mats
The cell-to-cell barriers are now available in additional thicknesses and material variants – from a compact multi-layer structure with a foam or elastomer compression layer to a UL94-V0-certified heat shield with adhesive tape. Depending on the application, they can be engineered to balance thermal resistance, mechanical stability, and durability. They can also be adapted to specific compression properties, tolerance to cell swelling, and various cell chemistries, including NMC, LFP, and emerging formulations. The venting foam mats are positioned above the cells. In case of thermal runaway, they protect neighboring cells.
A broad product range on display
A demonstrator at the show vividly illustrates how the company’s busbar seals compensate for thermally induced changes in length and ensure a durable seal against media and the environment. At the same time, they permit defined movements of the busbar within the system.
In addition, the company will offer a preview of its advanced battery cooling program and its growing portfolio of components for heat pumps in electric vehicles. Freudenberg’s battery solutions serve both automotive and general industry applications, including industrial and residential battery energy storage systems.
“Whether it’s cell caps, thermal barriers or thermal management, we consistently turn standard components into high-performance solutions – exactly what our customers need across automotive and industrial applications,” says Andrea Giordano, head of the Battery Cell Caps & Thermal Barriers team at Freudenberg Sealing Technologies’ Pinerolo site.
Further details will be available live at Battery Show Europe, June 9 to 11, 2026, Stuttgart, booth F20 in hall 3.
For more information, please visit: www.fst.com/markets/automotive-truck-bus/electric-vehicle
