Battery film slitting

Precision-slit battery films for the energy transition

Demand for high-performance battery systems is growing rapidly. Whether electromobility, stationary energy storage, or portable electronics: lithium-ion batteries are everywhere, and their safety and performance depend significantly on the quality of their film components. Every separator film, every electrode film, and every insulation film must be cut to exact dimensions so that the battery cell functions reliably and no safety risks arise. Gotthardt Isolierteile GmbH (GOBA) has specialized in the precision slitting of technical films and insulation materials since 1962. With a slitting tolerance of +/- 0.1 mm, low-contamination processes, and ISO 9001-certified quality management, we offer you reliable contract slitting for all battery films.

Materials we slit

Separator films

Separator films are the heart of every lithium-ion battery cell. They separate the anode from the cathode, preventing an internal short circuit while simultaneously enabling ion transport. We slit separator films from a wide variety of base materials precisely to your desired width:

• Polyethylene separators (PE): single-layer and multi-layer, for standard and high-performance cells
• Polypropylene separators (PP): temperature-stable and chemically resistant
• Ceramic-coated separators: with Al2O3 or SiO2 coating for improved thermal stability and higher safety
• Trilayer separators (PP/PE/PP): shutdown function at over-temperature

Electrode films

Current collector foils form the conductive base for anode and cathode. Their cut quality directly influences the electrical performance and longevity of the battery cell:

• Copper foils: as anode current collectors, typical thicknesses from 6 to 20 micrometers
• Aluminum foils: as cathode current collectors, typical thicknesses from 10 to 25 micrometers
• Coated electrode foils: foils already coated with active material, slit lengthwise

Battery insulation films

Within battery modules and packs, insulation films ensure electrical separation and protection of individual cells or cell groups:

• Cell insulation films: electrically insulating films between individual battery cells
• Thermal insulation films: for protection against heat propagation during thermal runaway
• Battery wrapping films: outer wrapping of cylindrical and prismatic cells
• Pouch cell films: aluminum composite films for pouch cell housings

Thanks to this wide range of materials, we can cover virtually every film type used in modern battery production. If you need a material not listed here, please contact us. We will be happy to assess feasibility.

Technical capabilities for battery film slitting

Why precision is critical for battery films

With battery films, it is not just about dimensional accuracy, it is about safety. An unclean cut on a separator film can create microscopic defects that lead to an internal short circuit during operation and, in the worst case, to thermal runaway. Burr formation on electrode foils increases the risk of dendrite growth. And particle contamination can permanently impair the electrochemical performance of a cell.

This is why the requirements for battery film slitting are particularly high:

• Burr-free cut edges: clean edges without fraying that could damage the separator material
• Low-contamination process: minimal particle exposure throughout the entire slitting process
• Consistent web tension: uniform tension over the entire roll length to prevent stretching and wrinkling
• Minimum slitting width from 5 mm: even the narrowest strips for special cell formats are achievable

GOBA machine park and specifications

Our slitting machines are designed for precision longitudinal slitting of web-based materials. Key technical specifications at a glance:

Through the combination of highly precise blade configurations and experienced machine operation, we ensure that every roll meets your specific requirements, whether thin 6-micrometer copper foil or robust ceramic-coated separators.

Application examples for precision-slit battery films

Lithium-ion batteries for electric vehicles

The automotive industry relies on large-format lithium-ion cells with the highest demands on quality and consistency. For series production of battery cells in gigafactories, separator films and electrode foils are needed in precisely defined widths. GOBA delivers precision-slit rolls that integrate seamlessly into automated winding and stacking processes. Our slitting tolerance of +/- 0.1 mm ensures that every roll meets the tight specifications of cell manufacturing.

Stationary energy storage systems (ESS)

Large-scale battery storage for grid stabilization and the integration of renewable energies requires reliable cell components in large quantities. Here we slit separator films and insulation films for prismatic cells and pouch cells used in industrial energy storage systems. The scalability of our equipment allows us to handle both prototype quantities and large series economically.

Battery modules for commercial vehicles

Electric buses, vans, and construction machinery place particularly high demands on the robustness of battery modules. Thermal insulation films and cell insulation films must reliably protect against vibrations, temperature fluctuations, and mechanical stress. We slit these films to exact dimensions so they can be precisely integrated into module housings.

Battery packs for e-bikes and power tools

Even in the field of small-format battery packs for electric bicycles, cordless drills, and other portable devices, precision film slitting is essential. Especially for cylindrical cell formats (e.g., 18650, 21700), narrow insulation and wrapping films are needed. Thanks to our minimum slitting width of 5 mm, we can reliably meet these requirements as well.