1.5 Dry Mixing & Coating

Instead of mixing battery materials into a wet slurry, dry electrode manufacturing works directly with dry powders. This innovative approach skips the need for liquid solvents (like NMP or water) and the large, energy-intensive ovens used to dry wet-coated electrodes. The active material is first homogenized and pre-conditioned in a mixing process, arriving at the next stage as a powder or granules. This material is then fed to a pair of rolls that rotate in opposite directions, sometimes at different speeds. A dry film of the active material forms on the faster-moving roll.

Depending on the system, this dry film can either be generated first as a free-standing electrode and then applied to the current collector foil, or it can be calendered directly onto the substrate foil. Direct calendering and free-standing electrode production are currently the most promising dry processing technologies with high potential for quick adoption by industry. Before the dry film is applied, it is usually cut to the desired width.

The main goals of this method are to make battery production greener by using less energy and avoiding the harmful chemicals and solvent recycling steps common in traditional electrode manufacturing. This also simplifies factory setups and potentially allows for the use of new types of battery materials. Leading battery makers are already using or exploring these "dry" methods.