Tool Steel Metallurgy Fundamentals for High Volume Battery Component Manufacturing Dies
Powder metallurgy tool steels with cryogenic phase stabilization eliminate edge chipping and cut amortized tooling costs by over eighty percent in battery dies.
AA3003 Impact Extrusion
Meaning
Metal forming processes that use high-speed press strikes to shape aluminum alloy into hollow cylindrical shells are standard in lithium-ion battery can manufacturing. AA3003 impact extrusion drives a lubricated metal slug into a die cavity under extreme pressure, forcing the ductile material to flow upward around the punch. This cold-working technique defines the final wall thickness of rectangular or cylindrical cell housings.
The method reaches its limit when the height-to-diameter ratio of the can exceeds twelve, at which point tool drift threatens to cause non-uniform wall thickness.
Process Mechanism
Mechanical forces during the punch stroke cause the solid slug to undergo rapid plastic deformation. Forcing AA3003 impact extrusion to proceed with high punch velocity requires specialized double-action mechanical presses.
Material Behavior
Work hardening during deformation increases the yield strength of the aluminum casing, which improves its mechanical resistance to internal cell pressures. The manganese addition in AA3003 impact extrusion provides the alloy with high ductility and moderate strength. This balance allows the metal to flow smoothly without tearing during the press stroke.
The resulting container exhibits excellent corrosion resistance to acidic electrolytes.
Casing Quality
Dimensional variation in the finished container is governed by punch alignment and lubricant consistency. Achieving high dimensional accuracy in AA3003 impact extrusion prevents variations in the internal volume of the battery can. Symmetrical flow ensures that the can top remains flat for the subsequent laser-welding of the cap.
Thermal expansion of the tooling during continuous operation represents the primary boundary for process capability.