While very fast charging may have been the main motivation for engineering the upcoming Porsche Mission E on a new 800-volt platform—versus the 400-volt standard used for every other current EV—the decision won’t disadvantage the EV in the measures that matter a lot to Porsche buyers: performance, of course. So far, Porsche has teased us with news that there are separate motors for the front and rear axles, with a combined output of more than 600 horsepower, and acceleration times of less than 3.5 seconds to 60 mph and less than 12 seconds to 124 mph.
Those figures don’t leave the Tesla Model S in the rearview mirror, but when it comes to track-day lap times, you’ll want to place your bets on the Porsche. The Mission E has been developed to be able to repeat its peak performance out on the track all day—or, more accurately, until the charge runs out. “High continuous output, acceleration reserves, and reproducibility with power takeoff are essential features of Porsche electric motors,” said Albrecht Reimold, member of the executive board for production, in a recent corporate release.
Joachim Kramer, Porsche’s director of power electronics for the Mission E and other electric-vehicle projects, recently elaborated in an interview with C/D that it isn’t just the motor but the battery pack and all the power electronics that have been engineered for serious track time. And for the most part, those attributes are part and parcel of the decision to charge the battery so quickly.
Fast Charging and Fast Driving
“The quick-charge cooling demand on the system is not higher than the demand when we go on a racetrack,” said Kramer. “And that’s our development goal: to perform on the Nürburgring or other racetracks.”
According to Kramer, a single liquid-cooling system is designed to take care of the battery and all the power components, adjusted for what each of those components can withstand. The battery can’t go beyond 158 degrees Fahrenheit, for example, while the motor can operate just fine at much higher temperatures. The cabin air-conditioning compressor contributes to help regulate and cool the systems during fast charging or fast driving. Additionally, Porsche saved weight on copper wire and connectors by moving to 800 volts and cites lower losses—meaning less heat generated—across the entire power system.
Porsche and the battery-cell supplier together defined durability tests, assuming “quite a bit of quick charging” at the quickest Turbo Charging rate, which is anticipated to be 320 kW, according to Kramer, but he added that Porsche doesn’t see Turbo Charging every single time as standard use.
Going with 800-volt technology doesn’t mean that the lithium-ion battery cells Porsche uses in the Mission E need to be any different than those Audi uses in its upcoming electric vehicles, for example; rather, it’s a matter of configuring them in series rather than in parallel. Yet Kramer confirmed that, at least at launch, the Porsche battery is slated to be a bit different. “We put some Porsche differentiation in the chemistry . . . We at Porsche have a bit more demand for power,” he said.
A Hefty Bill Up Front
The voltage standard for its EVs isn’t the only thing Porsche is planning to double. The automaker recently announced that it was doubling its planned investment in electric and electrified vehicles by 2022, pouring more than $7 billion into development. For a vehicle that Porsche anticipates building at a rate of only 20,000 per year, one that it says it will sell for starting prices well under $100,000, that is a gulp-inducing sum. This one car wouldn’t justify it.
Porsche may propagate its 800-volt tech to other high-end vehicles in the Volkswagen Group in the near future—and to other Porsche models. It’s already teased the possibility of other all-electric models—such as the Cayman e-volution, which puts the Mission E’s technologies into a traditional sports-car package. And there’s Porsche’s upcoming entry into Formula E racing next year. We wouldn’t be surprised to see some impressive lap times as well as some Ludicrous-style bragging.