Copyright RACER
Formula E often positions itself as a proving ground for electric road car development, something Porsche is proving with its new Cayenne Electric. The SUV features a number of developments stemming directly from the brand's championship-winning participation in Formula E, with the car developed at Porsche’s development center in Weissach, Germany where the development teams from the motorsport and road car divisions work together under the same roof. “Formula E is our development lab for the electromobility of tomorrow. This is where we gain valuable insights for our road-going sports cars,” said Dr Michael Steiner, member of the board of management for research and development at Porsche. “The new Cayenne Electric shows how quickly such a technology transfer takes place at Porsche and how relevant our commitment to the electric racing series is to series production.” Florian Modlinger, director of factory Motorsport Formula E and team principal of the factory Porsche Formula E team, adds, “In Formula E, efficiency is the difference between victory and defeat. This principle also shapes the Cayenne Electric. Efficiency is not only the focus in terms of the vehicles themselves; the agile working methods proven in racing can also help to shorten development times and accelerate the transfer of technology.” The technology transfer from race to road is a somewhat expected one, but the transfer goes both ways, with the 99X Electric Formula E car also benefiting. The charging sockets and plugs of the racing car are entirely identical to those used in Porsche EV road products, with the Combined Charging System (CCS) being the standard across both road cars and Formula E. Transferring from race to road, a key thing is cooling, with the Cayenne Electric's electric drive system components cooled directly with a specially developed liquid, something the Formula E team has been using since its debut in the category in 2019 and is now making its way into a production product for the first time with the Cayenne Electric. Typically, coolant flows through a jacket outside the stator, but Porsche's innovation allows coolant to flow directly along the copper conductors via stator grooves, meaning the heat is dissipated directly where it is generated. The change enables efficiency of up to 98 percent with the Cayenne Electric – a number that's even higher in the Formula E car. Formula E's focus on efficiency, centered around recuperation of energy, is something that also transfers. In Formula E cars must start with 38.5 kWh of usable energy, but can increase that number through regenerative braking. The Cayenne electric has up to 600 kW of recuperation power available, giving it the same peak power output of the 99X Electric. In everyday driving, up to 97 percent of braking is done purely electrically without the need of typical mechanical brakes. “The challenge of recuperation is highly complex,” said Modlinger. “When braking, we want to recover as much energy as possible while reducing speed as quickly as possible. Depending on brake pressure, we also engage the front wheel brakes. The car’s balance should match the driver’s preferences – it contributes to their confidence in the car and, as a consequence, to performance. “On the road, it’s also a matter of driving safety. To bring all this together, a variety of software functions are active during braking – a huge area for potential knowledge transfer.” Since last season Formula E has featured fast-charging pit stops, with 10 percent of usable energy capable of being added in a 30-second charge. The Cayenne Electric can increase its state of charge (SoC) from 10 percent to 80 percent in less than 16 minutes. Porsche aims to achieve its high charging performance in any condition. When the SoC is up to 55 percent in the Cayenne Electric, charging power is more than 350 kW – more than 300 km of range can be added within a 10-minute charge. It’s another development that can find its origins in Formula E. “The drivers [in Formula E] push the cars to the limit – sometimes in scorching-hot cities, such as Jakarta. When we come into the pits to charge, the system temperatures are often very high," said Modlinger. "At the same time, we want to keep the cooling requirements on the racing car as low as possible, because cooling consumes energy and, depending on the hardware, increases weight. “So, during Pit Boost pit stops, we demonstrate an energy supply with enormous charging power under extreme conditions.” The main focus of Porsche investment in Formula E is in components and technologies that can be relevant for road use. They might not be visible to onlookers, but they are crucial, making Porsche’s involvement in the category vital in its development of electric vehicles for consumers. “Our technical challenges are not visible from the outside,” said Modlinger. “But they are considerable and, in many areas, they are similar to those we face in our electric road-going sports cars.”
