New, 800V, electric cars, will recharge in half the time14 October, 2021 / Articles
Pump up the voltage!
Electric vehicles (evs) are becoming commoner. Some 750,000 of them were sold in the first quarter of 2021 according to jato Dynamics, a British consultancy. jato reckons evs now account for just over 4% of new-car sales, up from 2% in the same quarter last year. Yet many potential buyers still suffer from “range anxiety”, a wariness about having to interrupt a long journey while an ev’s battery is recharged. The good news is that the time required to do this is about to be slashed.
Most evs operate at 400 volts (400v). But a number of producers and their component suppliers are now gearing up to introduce 800v drive systems. Higher voltages supply the same amount of power with less current, which means electric cables can be made lighter—the consequent weight saving helping to increase a vehicle’s range, says Christoph Gillen, a technology director for gkn Automotive, a British components group which recently announced that it is accelerating its development of 800v drive systems. As most cabling is made from copper, the price of which has been soaring, this should also save carmakers money.
What drivers are most likely to notice, though, according to Dr Gillen, is that vehicles with 800v drive systems will be able to make greater use of some of the latest fast chargers. For instance, Ionity, a German company backed by a number of carmakers, is building a network of 350kw fast chargers across Europe. These automatically optimise charging speed to the maximum that a vehicle can handle. Using one of these, an ev with an 800v system will be able to recharge about twice as quickly as a similar vehicle with a 400v system.
Fast chargers are also more efficient. All chargers take electricity from the grid, which uses an alternating current (ac). When an ev is plugged into a standard charging point, its systems convert ac into direct current (dc), which is what a battery needs to store electricity. Fast chargers bypass the vehicle’s converter, using their own beefier bits of kit to pump a dc charge directly into the battery.
The first ev to use an 800 v drive system was the Porsche Taycan, a luxury sports saloon. This was launched in 2019. According to Porsche, by using a fast-charger the Taycan’s huge 93k wh battery can, in a little more than five minutes, gather enough juice for the car to travel 100km.
Two South Korean producers, Hyundai and its partner Kia, launched their first 800v vehicles this year. Kia says the 77kwh battery in its ev6, which went on sale on August 2nd, can be recharged from 10% to 80% in 18 minutes. (The last 20% of capacity is charged at a slower rate in most evs, to prevent damage to the battery. Hence a full recharge is typically carried out overnight on a standard charger.) Others have 800v vehicles in the works, too. They include General Motors, Volvo, byd and Stellantis (a large shareholder in which, for full disclosure, also has a stake in The Economist’s parent company).
Angst and amps
Turning an ev’s battery from a 400v to an 800v system is fairly straightforward. Principally, it involves wiring up more of the battery’s cells in series. But the associated electronics need additional re-engineering. The main reason why the current generation of evs use 400v is that semiconductors able to handle higher voltages have not been readily available.
Now that ev sales are growing strongly, though, specialist chipmakers are investing in semiconductors that can operate at 800v. Instead of using transistors made from pure silicon, those employed by these chips are made from silicon carbide, which is more robust. Safety systems in vehicles, such as automated circuit breakers which isolate the battery in the event of a crash, also need to be upgraded.
What all this means is that, as more 800v evs come onto the market, and batteries continue to improve with increased capacity, more motorists are likely to be persuaded to go electric. Much, however, will depend on the availability of fast-charging infrastructure. If stations are easy to find, and topping up batteries takes only the amount of time required to pick up a coffee, then the malady of range anxiety will at last be laid to rest. ■
An early version of this article was published online on August 18th 2021