• Energy Research

The use of thicker electrodes can contribute to a reduction in cell costs. However, the properties of the electrode must be kept in view to be able to meet the performance requirements. Herein, the possibility of simultaneous multilayer slot die coating is investigated to improve the electrode properties of medium‐ and high‐capacity anodes. The stable coating window of the two‐layer slot die coating process is investigated to produce property‐graded multilayer electrodes. Electrodes with different styrene–butadiene rubber (SBR) gradients are investigated with regard to adhesive force and electrochemical performance. An increase in the adhesive force of up to 43.5% and an increase in the discharge capacity is observed.

In industrial lithium‐ion battery manufacturing, patterned structured electrodes are required due to subsequent processes. In particular, novel and advanced cell stack formation processes cause challenging design requirements for electrode geometry. This work examines the influence of coating speeds up to 50 m min–1 and wet‐film thicknesses up to 400 µm on the coating edge quality. To determine the coating edge quality, the start‐up length in every pattern in the coating direction is compared for different coating parameters. Parameters such as speed and film thickness show no limiting effect, which makes high process speeds possible.

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.