Millions of cars on the road today in Europe bear Gilles Le Borgne's imprint. Before being named head of engineering at Renault Group in 2020, he held a similar post at PSA Group, now part of Stellantis, where he worked for three decades. Le Borgne has taken on even more responsibility at Renault since February, when he was named chief technology officer. Le Borgne, a two-time Automotive News Europe Eurostar winner, recently spoke with ANE Associate Publisher and Editor Luca Ciferri and News Editor Peter Sigal about his most pressing challenge: How to improve the efficiency of electric cars so they are more affordable and sustainable.
Efficiency, as measured in kilowatt hours per 100 km, is becoming a critical topic for electric cars. Where is Renault now?
We are in the vicinity of 13 kWh/100 km for the Megane E-Tech (compact), which has a WLTP range of up to 470 km. We know that drivers can reach 450 or even 480 km in normal temperature conditions. This is where we stand right now but we are working on all aspects that influence efficiency.
What are some of those areas?
Regarding the powertrain, when you consider the motor, inverter and the power electronics, we are at a little less than 86 percent global efficiency [meaning the percent of electricity that powers the wheels]. The motor plus power electronics, about 90 percent. We are working on the next generation of EVs, which will arrive around 2027 and will include motors developed with Valeo. We are sticking with an EESM [externally excited synchronous machine], double winding motor with rotor and not with permanent magnets. We hope to increase the efficiency of the motor plus power electronics to 93 percent, which is quite good compared with a permanent magnet motor.
What about charging?
We are moving to gallium nitride (GaN) technology for the charging to gain something around 2 or 3 percent efficiency compared to current silicon-based technology. When you start with a conventional DC/DC with a silicon IGBT [insulated gate bipolar transistor power module, or switch], you are somewhere around 93 percent efficiency, and with GaN we hope to be around 95 to 96 percent. This will appear with the generation of EVs launched around 2027.
And on the battery side?
We will move to 800 volt for that generation, lowering the resistance of the cells. Another important point around the battery is preconditioning the temperature before you charge. Thanks to Google’s route planner, when you plan a recharge, the car knows you are going to stop and in case of cold conditions, it warms the battery to be more efficient at the start of the charging. But you need to use the route planner. It’s very, very efficient: When you stop at -5 degrees, with a charge of 15 percent, it will take 46 minutes without preconditioning for the Megane to reach 80 percent charge. With preconditioning, it’s 24 minutes, so almost twice as fast. Experienced users know to extensively use preconditioning because it’s not only about fast charging, but also about cost. If you stop at a Ionity station, for example, when you have preconditioning you can lower the cost from 84 euros to about 20 euros (at -5 degrees) because it takes you 105 minutes charging with average power that is quite low without preheating, and with it you can go as fast as 24 minutes. You pay based on minutes, not kilowatts.