When Alejandro Agag first conceived the idea for Formula E — a racing series for electric race cars — he wanted to keep cost down in order to attract teams to the sport. For the chassis, he turned to an existing design manufactured by Dallara. The problem was, that car was expected to use a gasoline engine. To turn it into an electric race car, the battery had to fit into the same space usually reserved for the fuel tank.
The rules specify that the battery could not weigh more than 200kg. It was limited to a maximum bus voltage of 1,000 volts with a peak power limit of 200 kW and maximum usable energy of 28 kWh. Not only did the battery have to meet all those parameters, it had to be 100% consistent from one team to the next and last an entire season with no loss of power or performance. In fact, in the first season of racing, there was only one battery failure out of 440 race starts.
The company that made all this happen is Williams Advanced Engineering, a division of the Williams Formula One team. F1 has been using batteries for years to power its kinetic energy recovery systems (KERS). Recently, Williams was awarded the “Most Innovative New Motorsport Product” award for its Formula E battery at the Race Tech World Motorsport Symposium. It was also awarded the Simms Medal for 2015 by the Royal Automobile Club for its work on the Formula E battery, according to a report by Green Car Congress.
Formula E has decided to stick with the Dallara chassis through the end of season 5. That means improvements to the batteries it uses will be severely limited by packaging constraints. “Energy is probably more challenging than anything else because of the limited packaging space,” Williams lead engineer Gary Eckerold tells AutoSport. “The cell technology is developing without question so we would like to think by season three or four there’s a slightly improvement but you’re not going to get a massive step change between two and three. Unfortunately the chassis is static until season five. So in terms of packaging space, it’s still the same. ”
Formula E is considering raising battery power to 32 kWh with 250 kW of peak power. Eckerold thinks Williams can make that happen, even with the confined space it has to work with. The sport may allow the teams to seek their own battery supplier for season 5. Until then, Williams will continue to be the its sole battery supplier.