A roll-to-roll hot rolling press is engineered to create a permanent, low-resistance interface between two distinct layers using a combination of heat and moderate pressure.

Lamination in a battery pilot line typically involves bonding a free-standing active material (like a dry electrode film) to a foil that has been pre-coated with a thin conductive "tie-layer" or primer. (1) Thermal Softening: The rollers heat the binder (usually PTFE for dry processes or PVDF for wet) to its glass transition temperature (Tg). (2) Interfacial Fusion: Under pressure, the softened binder chains interpenetrate the primer layer on the foil, creating a mechanical and electrical "weld." (3) Nip Geometry: The rollers must maintain a perfectly uniform "nip" to ensure that the lamination strength is consistent across the entire width of the R2R line.

References:

M. Yokota, et al., Effect of roll press on consolidation and electric/ionic-path formation of electrodes for all-solid-state battery, Journal of Power Sources Advances, 2021, 12, 100078

R. A. Altmaier, et al., High-Linear-Energy Layered Fiber Batteries Using Roll-to-Roll Lamination and Laser Cutting, Adv. Mater. Technology, 2024, 9, 2400417.