Teardown: Next-Gen Battery Electric Drive Systems
Audi’s second generation of electric vehicle technology optimizes battery performance with several clever improvements.
Although the Tesla Model S has been on the market since 2012, practical electric vehicles (EVs) from traditional mainstream carmakers became available around 2017. This means some companies like Audi are ready to introduce the second generation of their EVs.
Along with its stablemates Porsche, Bentley, and Volkswagen, Audi is introducing its next generation of battery electric drive systems. The Premium Platform Electric (PPE) will be available on the newly unveiled Audi Q6 e-tron and was recently introduced on the second-generation Porsche Macan EV.
Audi Q6 e-tron with PPE. Image used courtesy of Audi
A Look at the EV’s PPE
The Q6 e-tron is an all-electric five-passenger SUV powered by two traction motors, one on each axle, providing all-wheel drive with 465 horsepower. The new platform integrates electronics architecture, charging and battery technology, and drive systems. It is scalable for use in various vehicles under the Volkswagen umbrella.
The completely redeveloped 800 V high-voltage battery used with the PPE has higher energy density than the company’s previous pack design, meaning it takes up less space in the vehicle. It is also designed for easier assembly, which helps reduce manufacturing times and costs.
PPE for the Audi Q6. Image used courtesy of Audi
The PPE lithium-ion battery has a capacity of 100 kWh. It comprises twelve modules of 180 prismatic cells with an approximately 8:1:1 ratio of nickel to cobalt and manganese in the cells. In addition to its design for easy manufacturing, the PPE pack has been developed for efficient thermal management, allowing for shorter charging time, greater range, and longer service life.
The battery housing has an integrated cooling plate that ensures an even heat transfer and produces high-temperature homogeneity within the battery. The plate is part of the battery structure, and a heat-conducting paste is placed between the battery modules and it.
PPE also uses navigation, route, departure time, and historical data from the driver to create a predictive thermal management system that calculates the need for cooling in advance, for example, when a steep grade is ahead. This can include pre-heating or cooling the battery before stopping for fast DC charging if it is required for the chosen route.
Preconditioning the battery can reduce charging times, and monitoring the battery temperature over the vehicle’s entire lifetime can extend the battery system's life. The Audi Q6 e-tron has a battery capacity of 100 kWh, and charging can be done with up to 270 kW. This means the 100 kWh battery can charge 10 to 80 percent in 21 minutes at a DC fast-charging station. In just ten minutes of charging, a range of up to 255 kilometers (158 miles) is possible.
An interesting charging feature with PPE comes into play if a charging station is working with 400 V technology. The 800 V battery is automatically divided into two battery banks at equal voltage, charged in parallel with up to 135 kW. In this case, each battery half is first brought to the same level of charge as the other, and then they are charged together.
Bentley Delays EVs with PPE
Although Bentley already has a hybrid gasoline-electric SUV called the Bentayga, the company was supposed to introduce an all-new, all-electric performance car based on the PPE system in 2025.
Bentley EV. Image used courtesy of Bentley Motors
Bentley has pushed back the EV for at least a year, with customer deliveries not expected until 2027. The reasons are not completely clear, but possible culprits are delays in the PPE program, which held up the launch of the Porsche Macan EV and the Audi Q6 e-tron models. Bentley has also moved its target to be all-electric by 2030 out to 2033 and will build more hybrid vehicles in the interim.
