Calendering revolves around three critical objectives: uniform density, enhanced conductivity, and mechanical stability. During this process, coated electrodes—comprising active materials, binders, and conductive additives—are fed through precision rollers to reduce porosity and thickness. For instance, a typical lithium nickel manganese cobalt oxide (NMC) cathode achieves optimal performance at 2.3–4.0 g/cm³ density, balancing ionic conductivity and energy storage capacity .
Key parameters include:
• Roller pressure: Dictates particle compaction, with excessive force risking cracks or delamination.
• Temperature: Softens binders for uniform adhesion without thermal degradation (e.g., PVDF binders at 60–90°C).
• Roller surface design: Textured or polished rollers adapt to materials like graphite anodes or high-loading cathodes .
Modern calendering machines, such as two-roll systems, achieve ±1μm thickness tolerance, ensuring consistency across flexible substrates like copper or aluminum foils .