Tesla grabs all the headlines because of its GigaFactory going up in the Nevada desert, but other companies are not snoozing when it comes to creating the batteries for the cars of the future. At Audi’s competence center for high-voltage battery technology in Gaimersheim, Germany, it is not only experimenting with new battery chemistry, it is designing the battery packs that will power all Audi, Volkswagen and Porsche electric cars in coming years, like the R8 E-tron, Q6 Quattro E-tron and Porsche Mission E 4 door electric sports sedan.
One of the areas it is focusing on is creating a standard battery module and rack mounting system that can be adapted to many different cars. Its battery module is made from aluminum and is about the size of a shoe box. It can accept cylindrical, prismatic or flat battery cells, depending on the particular needs of the car it is intended for. Cylindrical battery cells can store the most amount of energy but have less power than the others. Prismatic and flat cells are easier to package in the battery module. They can occupy 75% of the available volume whereas cylindrical cells can only fill 50% of the interior volume.
Audi says, “Pouch cells and prismatic cells are more versatile. With minor changes to their exterior dimensions, they can be configured specifically for maximum power output, maximum energy or a combination of both, making them ideal for a plug-in hybrid vehicle.”
According to a report at InsideEVs, Audi has increased the current capacity and energy density of prismatic cells by 50 percent over the past three years. Pouch cells now achieve up to 550 watt hours per liter of volume and Audi expects to increase that by 50% over the next 10 years. Most importantly, the cost of batteries has been cut in half over the past 5 years.
The mounting system that Audi has developed for its battery modules incorporates cooling tubes to control the temperature of the battery pack. The mounting rack is being optimized to fit as many different models within the Volkswagen Group as possible. The design parameter for Audi batteries calls for them to last 100,000 miles without any detectable decrease in performance.
Audi is one of the few manufacturers with its own internal battery research program. Most others are relying on competition between battery manufacturers to make the best batteries available for their cars at the best price.