New manufacturing approach for metal-coated polymer current collectors developed by Fraunhofer FEP
Fraunhofer FEP, a renowned research institute, has developed a groundbreaking roll-to-roll production process for manufacturing metal-on-polymer current collectors for lithium-ion batteries. This innovative method offers the potential to significantly enhance battery safety and energy density [1][3].
### Key Features of the Process
The process involves depositing ultra-thin layers of copper and aluminum onto 12-micrometer polyethylene terephthalate (PET) polymer films. The layers are approximately 1 micrometer thick on each side. The roll-to-roll technique allows for industrial-scale production on equipment capable of handling polymer webs up to 60 centimeters wide [3]. Electron beam evaporation ensures the metal coatings are uniform, defect-free, and bond securely to the polymer substrate, achieving electrical conductivity and thickness comparable to conventional 8-20 micrometer thick metal foils [3].
### Advantages for Lithium-Ion Batteries
The lightweight polymer films coated with thin metal layers significantly reduce the overall battery weight without compromising electrical performance [1][3]. Batteries assembled using these metal-on-polymer current collectors demonstrated electrochemical properties and cycle stability comparable to those with traditional metal foil collectors across various charging and discharging rates [1].
Moreover, the polymer-based current collectors reduce the risk of metal dendrite growth and mechanical stress-related failures, thereby enhancing battery safety. The weight savings also contribute to a higher energy density by allowing more active material or reducing overall battery mass [1].
### Implications for the Industry
Fraunhofer FEP's new production process offers the industry a valuable basis for optimising lithium-ion batteries. The technology enables the precise application of copper and aluminum layers onto polymer films, paving the way for the development of batteries with improved properties [2].
The new technology has already been successfully integrated into pouch cells by TU Braunschweig, demonstrating its potential for industrial-scale production [1]. Furthermore, the new roll-to-roll process for metal-on-polymer collectors can be successfully manufactured using semi-industrial processes [1].
Lithium-ion batteries, while widely used in mobile devices, robot vacuum cleaners, and electric vehicles, have a major disadvantage due to the properties of lithium, which can lead to a risk of fire [4]. The new metal-on-polymer current collectors have the potential to minimise these safety risks associated with lithium-ion batteries [1].
If a short circuit occurs in the battery cell, the polymer substrate melts and interrupts the current path, preventing thermal runaway [1]. This feature further enhances the safety of lithium-ion batteries. Additionally, the reduced weight of the collectors leads to a higher energy density of the cell [1].
Cells with metal-on-polymer current collectors have performed similarly to reference cells in terms of performance and cycle stability at different charging and discharging rates [1]. This consistency in performance suggests that the new technology is a promising development for the lithium-ion battery industry.
[1] Fraunhofer FEP (2021). Fraunhofer FEP develops new current collectors for lithium-ion batteries. [online] Available at: https://www.fraunhofer.de/en/press/research-news/2021/november/fraunhofer-fep-develops-new-current-collectors-for-lithium-ion-batteries.html [2] Fraunhofer FEP (2021). Fraunhofer FEP and TU Braunschweig develop new production process for metal-on-polymer current collectors. [online] Available at: https://www.fraunhofer.de/en/press/research-news/2021/november/fraunhofer-fep-and-tu-braunschweig-develop-new-production-process-for-metal-on-polymer-current-collectors.html [3] Fraunhofer FEP (2021). Fraunhofer FEP successfully demonstrates deposition of thick copper and aluminum layers on 12 μm thick PET films using roll-to-roll process. [online] Available at: https://www.fraunhofer.de/en/press/research-news/2021/december/fraunhofer-fep-successfully-demonstrates-deposition-of-thick-copper-and-aluminum-layers-on-12-micrometer-thick-pet-films-using-roll-to-roll-process.html [4] Fraunhofer FEP (2021). Fraunhofer FEP develops new production process for lithium-ion batteries with improved properties. [online] Available at: https://www.fraunhofer.de/en/press/research-news/2021/december/fraunhofer-fep-develops-new-production-process-for-lithium-ion-batteries-with-improved-properties.html
- The novel roll-to-roll production process developed by Fraunhofer FEP for manufacturing metal-on-polymer current collectors utilizes technology for both deposition and bonding of ultra-thin copper and aluminum layers, potentially revolutionizing the field of science and technology for lithium-ion battery production.
- Advancements in science and technology, such as the development of lightweight, safe, and energy-dense lithium-ion batteries with metal-on-polymer current collectors, have significant implications for various industries, including mobile devices, robotics, and electric vehicles.
