Liquid Cooling Jacket & Stator Thermal Optimization for High-Power EV Traction Motor

01. The Engineering Challenge

Under continuous high-torque draw, copper end-turn temperatures in a 180kW permanent magnet traction motor exceeded thermal class limits (180°C), causing localized winding insulation degradation and risk of demagnetization.

02. Technical Objective

Redesign the circumferential spiral water-glycol cooling jacket to reduce peak winding temperature by at least 18°C while maintaining coolant pressure drop below 45 kPa across a 15 L/min flow rate.

03. Multi-Physics Simulation Methodology

Constructed a conjugate heat transfer (CHT) model coupling 3D Navier-Stokes turbulent coolant flow with 3D anisotropic thermal conduction across laminated stator iron and orthotropic copper-epoxy coil winding packs.

A fully conformal 3D grid comprising 24.8 million polyhedral cells was generated, maintaining 12 prism layers along channel walls to ensure y+ ≤ 1. Fluid-solid thermal boundary matching enforced strict heat flux continuity:

04. Diagnostics & Redesign

Identified severe flow stagnation zones and non-uniform thermal dissipation along the axial drive-end. Introduced variable-pitch helical cooling channels with internal vortex turbulators to promote boundary layer regeneration.