Immersion cooling for high-power inverters: a highlight from Powertrain 2025
The Powertrain 2025 Congress, held on June 11–12, 2025, in Port Marly, gathered key players from the electrified powertrain community to showcase innovations driving the future of e-mobility. Among the contributions, IFP Energies nouvelles & TotalEnergies presented a study on dielectric oil immersion cooling for high-power-density inverters, drawing significant attention from OEMs and suppliers aiming to improve powertrain compactness and thermal management.
Photo : Cédric Helsly
Pushing the boundaries of thermal management
Titled “Design and Development of a High-Power Density Inverter Using Dielectric Oil Immersion Cooling”, the paper by Alexandre Battiston, Hakim El Bahi, and their team demonstrates a multi-physics approach (electrical, thermal, mechanical) to designing inverters capable of delivering 200 kW while maintaining compactness and reliability.
Key takeaways:
- Immersion cooling with dielectric oil enables more efficient heat dissipation compared to air cooling, especially for component that are typically not cooled directly within the inverter casing, allowing for smaller, lighter inverter designs.
- Innovative use of anti-noise ceramic capacitors effectively mitigates bubbles formation during operation, a critical challenge in immersion environments.
- CFD modeling and experimental testing validate the system’s thermal performance, showing promising thermal gains on passive elements such as DC-link capacitors and busbars, while limiting the heating of the power part, particularly the SiC MOSFETs.
From Prototype to Demonstration
The project adopted a step-by-step validation process:
- Experimental testing on a scaled mock-up to evaluate oil–electronics interactions.
- Full-scale inverter demonstrator design using SiC MOSFETs on double-layer IMS boards without solder masks for enhanced thermal exchange.
- Testing under various load conditions to compare air and oil immersion cooling, with results demonstrating clear thermal advantages for critical components.
These developments pave the way for compact, high-efficiency inverters essential for next-generation electric vehicles.
Contact the authors :
Alexandre BATTISTON alexandre.battiston@ifpen.fr
Hakim EL BAHI hakim.el-bahi@totalenergies.com