Photo: Audi
Dr. Joachim Doerr must be really proud of what Audi has done with the Premium Platform Electric architecture. Also known as PPE, it underpins the Porsche Taycan and the Audi e-tron GT. Doerr is the project lead for that incredible platform, but he spent some time on LinkedIn talking about the MEB that the Q4 e-tron uses. To be more precise, he explained how thermal management works in Audi’s newest EV.
According to Doerr, the Q4 e-tron has two coolant circuits. The battery pack has a low-temperature circuit that is exclusive. The second circuit supplies the electric motors, power electronics, onboard charger, and DC/DC converter – which is to EVs what an alternator is to combustion-engined cars. This is a medium-temperature circuit. Both of them use a water/glycol mix as the cooling medium.
The battery pack is cooled thanks to flat channels located in the floor plate of the battery. When the weather is cold, a high-voltage heater raised the coolant temperature to keep the traction battery at around 30ºC. That’s important not only for driving the vehicle but also to fast charge. Cold batteries do not accept more electrons very willingly. When they are kept at the ideal temperature, they also last longer.
The coolant circuit for the other components runs above the battery pack, and it can be seen in the image above. It also shows that the onboard charger is behind the rear axle, in a position that looks pretty vulnerable if the car is rear-ended. Let’s hope it is protected enough not to demand a replacement with minor bumps.
Doerr also spoke about the heat pump, which makes thermal management more efficient by “using the thermal losses from the electric components and the temperature of the outside air.” As beneficial as that sound, the heat pump is an option on the Q4 e-tron. BYD already said that the heat pump for its e-platform 3.0 vehicles would be a standard feature. Perhaps Audi should reconsider and do the same.
The battery pack is cooled thanks to flat channels located in the floor plate of the battery. When the weather is cold, a high-voltage heater raised the coolant temperature to keep the traction battery at around 30ºC. That’s important not only for driving the vehicle but also to fast charge. Cold batteries do not accept more electrons very willingly. When they are kept at the ideal temperature, they also last longer.
The coolant circuit for the other components runs above the battery pack, and it can be seen in the image above. It also shows that the onboard charger is behind the rear axle, in a position that looks pretty vulnerable if the car is rear-ended. Let’s hope it is protected enough not to demand a replacement with minor bumps.
Doerr also spoke about the heat pump, which makes thermal management more efficient by “using the thermal losses from the electric components and the temperature of the outside air.” As beneficial as that sound, the heat pump is an option on the Q4 e-tron. BYD already said that the heat pump for its e-platform 3.0 vehicles would be a standard feature. Perhaps Audi should reconsider and do the same.
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