Cylindrical and Prismatic Cell Architecture Selection Guidelines
Choosing between cylindrical and prismatic cell formats demands balancing tooling capital, thermal conduction interfaces, and structural face pressure limits.
Jellyroll Winding
Meaning
Automated assembly lines introduce cylindrical geometry by rolling continuous strips of cathode substrate, separator, anode substrate, and outer insulation film around a central mandrel. Production equipment executes jellyroll winding to package high active area into compact cylindrical or prismatic cell formats. The process terminates at the application of outer wrapping tape prior to insertion into the metal can.
Flat pouch formats rely on Z-folding or sheet stacking rather than continuous rotational assembly.
Manufacturing Precision
Constant web tension control prevents separator wrinkling during high-speed rotation. Automated vision systems in jellyroll winding monitor overhang margins to maintain anode coverage over cathode edges.
Mechanical Stress
Bending flat current collectors around tight radii induces structural strain near the central core of the coil. Internal pressure distributions resulting from jellyroll winding can cause localized electrode buckling or delamination during subsequent thermal cycling. Outer turns experience lower mechanical strain, creating radial gradients in packing density and electrolyte wetting rates across the structure.
Microscopic fracturing of active coatings near the center spindle increases localized impedance.
Production Yield
Metallic contamination generated during slitting risks puncturing the thin separator layer during roll compaction. Quality management protocols evaluate jellyroll winding throughput against short-circuit test failure rates at the winding station. Cell factories adjust spindle acceleration profiles to eliminate mechanical defects before final casing insertion.