Interesting video comparing the differences between the Kia EV9 (adjustable 6 lead) and Ionic 5 motor (fixed 4 lead) designs.
Simply put, the Kia EV9 - 6 lead configuration enables "on the fly" (energized) switching from Wye to Delta to enable high torque at low speed (Wye) to high efficiency (Delta) at higher speed. This configuration also still allows the inductance of the individual phases to be used in the boost converter for charging ( 400V charging boosting to 800V battery cell configuration).
Example:
Simply put, the Kia EV9 - 6 lead configuration enables "on the fly" (energized) switching from Wye to Delta to enable high torque at low speed (Wye) to high efficiency (Delta) at higher speed. This configuration also still allows the inductance of the individual phases to be used in the boost converter for charging ( 400V charging boosting to 800V battery cell configuration).
Example: