Battery Cell Caps and Thermal Barriers: Advancing Safety in Electric Vehicle and Stationary Batteries

A modern lithium-ion battery can contain up to 200 individual cells. Each of these cells is sealed by a highly sophisticated cover assembly - the battery cell cap - which plays a central role in both performance and safety. These components ensure reliable power transmission, securely seal the sensitive cell chemistry, electrically isolate the poles, and allow the cells to be filled during assembly.

Manufactured from specially developed metal, polymer and plastic materials, the battery cell caps combine excellent chemical resistance with high mechanical strength. A precisely controlled assembly process - including crimping and welding operations - ensures an exact fit and consistent sealing quality. Integrated into each cap is a burst disk that allows gases to escape in a controlled manner in the event of an emergency, significantly reducing the risk of explosions or flash fires. Thanks to their modular design and the manufacturing concept behind, the caps can be adapted to a wide range of battery, module, and vehicle concepts. Freudenberg Sealing Technologies can leverage several months of prototype production (with more than 100 thousand samples produced) and is now preparing the launch of series production by the end of the year in Pinerolo (Italy), with a fully automated line securing best-in-class durability, quality and cleanliness standards.

Thermal Barriers for Fire and Heat Protection

In addition to cell caps, thermal barriers make a crucial contribution to overall battery safety. These single- or multi-layer components - engineered as high‑performance insulation systems based on advanced elastomeric technologies or temperature‑stable plastics - can withstand temperatures exceeding typical thermal‑runaway thresholds and protect critical battery components. Positioned between individual battery cells, on top of them or across the entire module or battery pack, they act as an effective barrier against heat and fire.

The primary objective is to slow down - or ideally prevent - thermal runaway in a single cell, thereby stopping a dangerous chain reaction within the battery system. At the same time, these thermal barriers support efficient temperature management by easing the load on cooling systems, stabilizing battery performance, and helping to extend overall service life.

Quality, Testing, and Integrated Expertise

All Freudenberg Sealing Technologies’ battery cell caps and thermal barriers are manufactured to the highest quality standards. Each component undergoes rigorous testing for tightness, mechanical durability, and reliable functioning of safety features. The combination of material expertise, vertically integrated manufacturing, and deep engineering know-how positions Freudenberg Sealing Technologies as a reliable development partner for the automotive and general industry.

With its battery cell caps and thermal barriers, the company delivers more than individual components. It provides integrated safety and efficiency solutions that contribute directly to the advancement of electric mobility and to safer batteries powering the vehicles of the future - as well as reliable stationary energy storage systems supporting the energy transition.