Researchers at the Fraunhofer Institute for Laser Technology ILT have developed laser-based technologies for the production of lithium-ion batteries that can be charged faster and have a longer service life. Laser-based drying is also more efficient for coating water-based electrodes. Fraunhofer ILT will present these technologies for battery cell production at Hannover Messe 2023.
Batteries play a central role in the mobility of the future. Fraunhofer ILT has developed two laser-based manufacturing technologies that save energy in production and enable higher-performance, longer-lasting battery cells.
Fraunhofer ILT has developed a system in which a diode laser performs the drying process for electrodes. Compared to conventional gas-powered continuous ovens, the diode laser is more energy efficient and requires less space.
Samuel Fink, group leader for Thin Film Processing at Fraunhofer ILT, explains the principle behind the process: “In contrast to the hot-air drying process, our diode laser projects a high-intensity beam onto the copper foil, which is coated with graphite paste. The jet-black graphite absorbs the energy. The resulting interaction causes the graphite particles to heat up and the liquid to evaporate. Drying with the diode laser will reduce the energy required by up to 50 percent and the space needed for a drying system on an industrial scale by at least 60 percent,” predicts Fink.
The Fraunhofer ILT team has improved the power density and lifetime of lithium-ion batteries by developing a modified 3D electrode structure. Using a high-power ultrashort pulse (USP) laser, they created channels in the battery electrode that shorten the ion path and accelerate the charging process.
“The short interaction time of the laser pulses is sufficient to ablate the material, but also prevents the holes from melting, which means that the battery does not lose power,” explains Matthias Trenn, team leader for Surface Structuring at Fraunhofer ILT.
To achieve the high throughput required for industrial production, the Fraunhofer team used a multi-beam setup with parallel process control. Four scanners process the foil in parallel, which enables continuous processing of the graphite layer.
“The next step is to scale up the technology from the prototype to an industrial production line,” says Matthias Trenn.
Find out more about Fraunhofer at ilt.fraunhofer.de.
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