Researchers at Fraunhofer Institute innovate techniques for producing metal-polymer conductors
The Fraunhofer Institute for Electron Beam and Plasma Technology (FEP) in Dresden has developed a groundbreaking technology that could revolutionise the lithium-ion battery industry. Funded by the Federal Ministry of Research, Technology, and Space, the "PolySafe" project promises lighter, safer, and more efficient battery cells.
The innovation lies in the roll-to-roll process that enables the coating of thin polymer films with copper or aluminium layers, just one micrometer thick, on both sides. This process is significant as it could potentially replace the traditional metal foils used as current collectors in lithium-ion batteries.
The key advantage of these new metal-polymer current collectors is the potential weight reduction. The lighter polymer substrate could increase the battery's energy density, allowing for more energy storage in the same volume or weight.
Despite the thinner and polymer-based structure, the coated films achieve electrical conductivity and layer thickness comparable to traditional metal foils. Battery tests in pouch cells showed similar charging, discharging behaviour, and cycle stability to conventional cells, demonstrating that performance is not compromised.
Another critical safety feature of this technology is the polymer carrier’s behaviour in short circuits. In such an event, the polymer melts and interrupts the current flow, which can prevent thermal runaway—a major cause of battery fires. This intrinsic safety mechanism makes lithium-ion batteries potentially safer.
The roll-to-roll process, combined with electron beam evaporation, allows for precise, wrinkle-free metal coatings on large rolls of polymer films (up to 60 centimeters wide), suited for mass production and integration into battery manufacturing lines.
Within the "PolySafe" project, copper and aluminium layers up to one micrometer thick per side were deposited on 12-micrometer thick PET films. The polymer substrate in the new current collectors is designed to melt in the event of a short circuit.
The TU Braunschweig is currently processing the finished metal-polymer films into pouch cells for further testing. The metal-polymer current collectors were tested by the TU Braunschweig for their charging and discharging behaviour.
In summary, the roll-to-roll metal-on-polymer coating process developed by Fraunhofer FEP delivers lighter, high-performance current collectors that enhance lithium-ion battery energy density and safety, paving the way for next-generation batteries with longer life, improved safety, and better suitability for applications like electric vehicles. The ongoing "PolySafe" project promises a promising future for safer and more efficient lithium-ion batteries.
- The development at the Fraunhofer Institute for Electron Beam and Plasma Technology is rooted in science and technology, as they've created a revolutionary technology for lithium-ion battery industry using a roll-to-roll process, which coats thin polymer films with copper or aluminium layers, significantly replacing traditional metal foils.
- This innovation in science and technology, known as the PolySafe project, not only provides lighter battery cells due to the use of polymer substrates, but also ensures increased energy density and potential safety improvements, as the polymer carrier melts in short circuits to prevent thermal runaway, making lithium-ion batteries potentially safer.
