High‐Speed Coating of Primer Layer for Li‐Ion Battery Electrodes by Using Slot‐Die Coating
Ralf Diehm, Marcus Müller, David Burger, Jana Kumberg, S. Spiegel, Werner Bauer, Philip Scharfer, Wilhelm Schabel
Abstract
A reduction of the inactive components can increase the energy density and reduce production cost of Li‐ion batteries. But an effective reduction of the binder amount also negatively affects the adhesion of the electrode. Herein, slot‐die coating of a primer layer for Li‐ion anodes is investigated. It is shown that the use of a primer layer with only 0.3 g m −2 can increase the adhesive force by the factor of 5 as well as the cell performance for anodes with low binder content. The process limits for a stable, defect‐free primer coating are investigated at coating speeds of up to 550 m min −1 . The limits coincide both for a setup without vacuum box and with vacuum box with theory‐based equations. By using a vacuum box, the minimum wet film thickness can be reduced by half.