Development for Cell Caps 2 is underway
With Cell Caps 2, Freudenberg Sealing Technologies is creating the next generation of battery cell caps for prismatic and cylindrical cells. The company is set to present the technology at Battery Show Europe in Stuttgart from June 9 to 11, 2026
Freudenberg will also be highlighting expanded cell-to-cell barriers, venting foam mats, and a preview of advanced battery cooling and heat pump components. Additionally, a demonstrator will illustrate how busbar seals are engineered to resist thermal expansion damage while maintaining reliable sealing performance.
Cell caps occupy a considerable portion of the cell volume and function to reliably seal the cell chemistry off from the environment while enabling the safe and reliable filling of the cell with electrolyte. Cell caps must also enable fast charging, incorporate safety mechanisms in the event of thermal runaway, and contribute to the cell's mechanical integrity.
Series production of the Cell Caps Generation 1 is increasing, while the next evolution, Cell Caps 2, is already underway. The core of the next generation consists of integrating the terminal in moulded rubber into the base plate of the cell cap:
To fix the terminals in the cell cap, liquid elastomer is injected into the gap between the poles and the cap base plate. The elastomer then permanently bonds these components together, providing gas tightness, mechanical robustness, and electrical insulation, with minimal parts and low mass, helping reduce overall battery weight.
Generation 2 technology can reduce the cell cap height by up to 30%, depending on customer requirements. An advantage that translates into higher energy capacity and a longer operating time.
Freudenberg is working on the mass production of a round cell cap that utilises all the advantages of the next-generation technology. The manufacturing process for these small components plays a critical role in optimising production costs. The cell caps can be manufactured using the same technology as valve stem seals, which the company produces in the millions.
The cell-to-cell barriers are 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. They can be engineered to balance thermal resistance, mechanical stability, and durability, depending on the applications. They can also be tailored 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 to protect neighbouring cells in the event of thermal runaway.
A demonstrator at the show illustrates how the company’s busbar seals compensate for thermally induced length changes and ensure a durable seal against media and environmental conditions. They also permit defined movements of the busbar within the system.
Freudenberg will offer a preview of its advanced battery-cooling program and its growing portfolio of components for heat pumps in EVs. The company’s battery solutions serve automotive and general industry applications, including industrial and residential battery energy storage systems.
Andrea Giordano, head of the Battery Cell Caps & Thermal Barriers team at Freudenberg Sealing Technologies’ Pinerolo site, said, “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.”
