Porsche Claims It Can Double Tesla’s Fast-Charging Rate
The new, all-electric Taycan will come with a mighty thirst. This charging technology will slake it
On the A13 highway in Germany, a harried mom pulls into a rest stop, her two restless teenagers in the back of the family’s electric SUV. She steers toward a row of 24 sleek, refrigerator-size obelisks, most already tethered to a vehicle, and parks in front of the unoccupied one she’d reserved en route. Unhooking the cable, she inserts the plug on its end into a port in the car’s rear left flank, behind a flap that resembles the fuel door of earlier decades. She and the teens head to the bathrooms and a warm café for the 15 minutes it’ll take to recharge the car.
On the way, they glance over at the travel plaza’s fossil-fuel section. It’s like a little slum, with oil stains on the tarmac, the smell of petrol fumes in the air, and drivers standing at their vehicles squeezing the grimy handles of fuel nozzles. At the fast charger she’s using, on the other hand, the whole process requires no human intervention beyond plugging in. Her SUV identified itself to the charging kiosk, her charging network authorized payment, and voilà, the torrent of electrons began. The cost of the recharge will be added to the amount the charging network deducts monthly from her payment account.
The 15-minute recharge gives the SUV another 375 kilometers (235 miles) of range; it might have been a few kilometers more if the day weren’t quite so chilly. Still, it’s more range than our driver will need to get to Prague, where she and the kids will meet her husband, already in the city on business.
This is the fantasy of the electric-vehicle future a decade from now. Will it come to pass? Hard to say. Fast charging is evolving quickly, and the technology, standards, and business factors that will shape the outcome are only now coming into focus. Certainly, there’s still a lot to be done. And the stakes are high: A McKinsey & Company report suggests that over the next decade, more than US $50 billion will be spent on EV charging sites.
Tesla was the first to get a sizable network of fast chargers up and running. The company now operates some 1,500 stations with more than 13,000 charging cables in North America, Europe, and China. Tesla unveiled its first 90-kilowatt Supercharger station in 2012, showing the world what a modern, pleasant, fast-charging site should look like. By 2015, Tesla drivers could cross the continental United States solely on electricity, with their cars’ navigation systems routing them through a succession of Supercharger sites, even telling them how long to stay plugged in to minimize wait time.
The rest of the industry intends to catch up in time for a new wave of long-range electric cars to hit the market in the early 2020s. Major car companies have aligned themselves with three competing fast-
charging standards. The standards they’re promulgating are incompatible, each having its own operating voltages and currents, physical connectors, control logic, and communication protocols between car and charger.
Nissan and Mitsubishi are behind a Japanese system called CHAdeMO, for “charge de move,” which is also an allusion, in Japanese, to the phrase “a cup of tea,” referring to the time required to recharge the vehicle. China, maker of two-thirds of the world’s lithium-ion batteries, has developed a standard called GB/T, for Guóbiāo tuījiàn (from the romanization of the Chinese term for “preferred national standard”). Meanwhile, all European and U.S. manufacturers except Tesla have lined up behind a standard called Combined Charging System (CCS), and even Tesla has said its Model 3 vehicles sold in Europe will have a CCS port.
The CCS group includes BMW, Daimler, Ford, GM, Hyundai, Jaguar, Kia, Renault, and, notably, VW Group. And within the VW Group, Porsche, the high-performance brand that’s arguably the group’s crown jewel, has made little secret of its intention to do Tesla one better.
Porsche’s new Taycan, the brand’s first all-electric car, was revealed to the world in production form as this article was going to press. The price will start around $90,000 and go as high as $130,000, close to the Tesla Model S pricing these days. The sedan’s performance roughly equals that of Tesla’s Model S. However, it will offer fast charging that’s much faster. Tesla’s Supercharger sites now operate at up to 135 kW, meaning a Tesla driver can add up to 320 km (200 miles) in as few as 30 minutes. The company plans to boost peak power at its sites to 250 kW over the next few years.
Final details will be made public only on 4 September. But if published reports are accurate, the Taycan will launch with 250-kW charging, and 350 kW will be possible by 2021 at the latest. That means 400-plus kilometers of range can be added in less than 20 minutes. In a real hurry? Figure on 100 km in 6 minutes.
Those levels of power demand the use of new hardware never before fitted to a passenger car. Besides more powerful charging stations, the system also requires a grid that can carry higher power levels to the charging sites, as well as many other enhancements. To roll all this out on a large scale, dozens of car companies will have to work with hundreds of charging networks, equipment suppliers, and, indirectly, with thousands of electric utilities around the world.
Today’s EV charging isn’t all that fast. It’s certainly not as quick at adding range as pumping gasoline. But that doesn’t matter so much, because most recharging is done overnight at home or during the day at the workplace. In North America, battery-electric vehicles are usually charged at 240 volts AC, using what are known as Level 2 charging stations. (Level 1 is the region’s standard 120-V wall current, adequate for adding 30 or 40 km overnight.) Depending on the car’s built-in charger—Tesla aside, they mostly range today from 3.3 to 7.2 kW—it can add 15 to 50 km (10 to 30 miles) each hour. In one night that’s enough to fully recharge a typical 60-kilowatt-hour EV battery pack, if it’s not completely depleted at the start.
Fast charging is a different story. First of all, it uses direct current instead of alternating. Other than Tesla, the electric cars on the road today are mostly limited to 50 kW, meaning it takes most of an hour to charge that nearly tapped-out 60-kWh battery to 80 percent capacity or up to 90 minutes for the larger 90-kWh battery packs in luxury vehicles.
The changes in the charging rate as the battery charges also affects the time a driver spends plugged in. Some cars, among them the Chevrolet Bolt EV, start to taper down the charge rate once the battery’s state of charge hits 50 percent.
|System||Public chargers worldwide||Kilowatts||Availability|
|Combined Charging System (CCS)*||22,000||50–350||United States,|
|China GB/T||330,000||237.5||China, India|
*North American and European versions are not compatible.
Sources: Columbia SIPA/Center on Global Energy Policy; Chargehub.com
The 125-kW Tesla Supercharger system also tapers, but today it provides up to 300 km in 25 to 45 minutes.
Those differences barely hint at the lack of uniformity in today’s charging networks. North America has a dozen or more individual public charging networks offering a mix of Level 2 and fast charging. Generally, drivers must belong to a network to use its stations. If not, they have to call a toll-free number and provide a credit card to an agent, who unlocks the station. Virtually no stations have credit card readers, as gasoline pumps do. Experienced EV drivers may have tags, fobs, or apps from as many as eight separate networks. The kind of roaming that mobile-phone operators enabled 15 years ago doesn’t exist in the United States, although Canada and Europe are considerably better in that regard. In 2019, several U.S. networks announced plans to allow future roaming with other individual networks—but those are bilateral agreements. The industry is still well short of cellular-style transparent nationwide roaming.
When Porsche set out to define its first electric car, it surveyed its customers about what they would want in a fast, pricey, high-performing electric sport sedan. As well as consistent performance throughout the battery range, the company found that buyers wanted recharging on road trips that didn’t take much longer than filling up with petrol. Porsche set a 15-minute target, 20 minutes at the outside. Payment had to be at least as easy as using a gasoline pump at a highway rest stop.
That’s what Porsche says it will deliver, sometime in 2021, in its Taycan and the 350-kW charging stations to follow that only the Taycan will be able to use. That exclusivity will be fleeting; other pricey EVs will incorporate the same standard. But Porsche will have achieved its goal of being first (and of beating Tesla).
Tesla, on the other hand, asserts that such extreme fast charging isn’t required. A company executive, interviewed on the condition that he not be named, said that surveys suggest Tesla owners value the quality of their recharging experience more than its brevity. Customers might relax in a café, go shopping, or simply chat with other Tesla owners. However, the company is starting to upgrade its existing Supercharger network to provide an average of 175 kW per car, or about half of what Porsche is promising, with a peak rate as high as 250 kW per car.
To learn more about how Porsche accomplished this remarkable piece of engineering, I visited the heart of its research operation this past March.
The two-lane roads between the outskirts of Stuttgart and the hamlet of Weissach rise and fall through sweeping, hilly curves with open fields on each side. They have no shoulders, which heightens the driver’s senses while moving in traffic that runs at precisely the marked limit of 100 km/h (62 mph). But the pace regularly slows as heavily loaded tractor trailers and car carriers packed with new Porsches navigate the bends—suggesting that Weissach isn’t your typical German farming town.
Indeed, it’s been the home of the Porsche R&D center for nearly 60 years. These days, it’s a hive of construction, with barricades, cranes, and road diversions that lead to new and expanded parking lots terraced into the hillside. From behind a tall wooden fence blocked by shrubbery and posted with strict warning signs comes the howl of cars tearing along the company’s closed high-speed test track.
I’m here on this sunny spring day to speak with Joachim Kramer, who leads Porsche’s work in high-voltage electronics for electrified vehicles. With the official Taycan launch just five months away, he’s a very busy man. His answers to many questions are guarded, to conceal specifications still being confirmed and also to ensure he doesn’t reveal to competitors any of the lessons Porsche has learned in the seven years since it first got a good look at a Tesla Model S.
Photo: Mary Turner/Reuters
Ask anyone what kind of fuel their car takes, and you’ll likely hear “gasoline.” Ask for more details, and the most you’ll get will be “regular” or “premium.” Now ask what kind of charging an electric car might have, and you’ll get a blank stare.
Explaining charging to car shoppers is hard. It sounds to most car buyers like you’re reading from an engineering specification. In fact, most of the following terms come from just such a list of specs. They are, nonetheless, the bare minimum that today’s modern electric-car buyer must know to sort out where a car can and cannot charge.
J1772: SAE International’s protocol and connector standard for Level 1 and Level 2 charging. Used on all electric cars except Teslas. (Varies between North America and Europe.)
Level 1: 120-volt AC charging in North America (the residential standard), via a charging cord with a J1772 connector.
Level 2: 240-volt AC charging in North America, also J1772.
CHAdeMO: DC fast-charging standard, used only for Japanese cars and a few early Korean models. Tesla offers a CHAdeMO connector for its cars.
CCS, or Combined Charging System: DC fast-charging standard, used by all European makers and all U.S. makers except Tesla. Its global use is promoted by a group called CharIN.
Supercharger: DC fast-charging standard usable only by Tesla vehicles.
No automaker, charging network, or standards body has proposed any way to simplify this gibberish into an easily understood, graphically intuitive system for signage, mapping, and vehicles. The closest anyone has come is the Chargeway graphic system privately developed by marketer and graphic designer Matt Teske. It uses a series of shapes, numbers, and colors to distinguish among types and speeds of charging. It is now being tested by the Oregon Department of Transportation at some pilot locations.
Kramer is confident Porsche will deliver the capabilities it has promised. The engineers encountered “no real surprises,” he says—though a few unexpected aspects required some novel engineering. The engineers faced a trade-off, he says, between battery capacity and charging speed. The bigger the battery, the less often charging is needed, but the pricier the car. They concluded the largest batteries in the most expensive electric cars will remain at 90 to 100 kWh for the next several years. “In 10 years, perhaps 200 kWh?” he muses.
That meant the power had to go up significantly. The company’s previous hybrids and plug-in hybrids operated at 300 to 400 V, the standard industry practice. But if you want your fast charger to use that voltage you’d have to boost the current substantially. That would mean increasing the size of the copper wires, adding more mass.
So the company doubled the voltage by connecting pairs of cells in series. With this 800-V system, Kramer estimates Porsche saved roughly 30 kilograms in the Taycan—a worthwhile amount even in a vehicle likely north of 2,000 kg. That mass savings is divided among the battery pack, power electronics, windings in the permanent-magnet motors that power the wheels, and the thick cables that connect it all together.
At a component level, the higher voltage required extra insulation, including wider air gaps between components, as well as other features. However, none of Porsche’s traditional suppliers offered such components. Those from other suppliers—MOSFETs for electric locomotives and other uses, for instance—weren’t qualified for the environmental conditions, temperature swings, vibration tolerance, and 10-to-15-year life required for road vehicles.
This is no ordinary supply problem. Very few, if any, high-volume mass-market products handle these levels of power and voltage. Magnetron tubes in microwave ovens, for instance, require a power supply of 1,000 V or more, but only at 1 or 2 amperes.
So Porsche had to work closely with suppliers to prototype, test, develop, and retest scores of new components. Kramer gets vague when asked about specific issues its engineers faced, but he identifies two in general terms: energy storage and electromagnetic radiation.
Both are strictly limited by vehicle regulators around the world. By law, an EV must be able to drain energy quickly from its high-voltage system, because in a crash that energy could shock and injure emergency responders cutting into the car to rescue occupants. Kramer says limiting energy storage requires diverting energy into multiple components—especially capacitors—that can be shut down simultaneously and rapidly.
As for radiation, Kramer will say only that the company identified it as a challenge in its higher-voltage prototypes, and that the design has shielded against it appropriately. Beyond preventing radiation from interfering with the vehicle’s electronics, regulators worldwide limit the radiation to levels they consider safe for human occupants and those in the vicinity of the vehicle. Kramer says simply that Porsches meet all such global regulations.
Kramer confirmed that Porsche will use the CCS standard in all markets except Japan, where the CHAdeMO standard is transitioning toward higher power levels, and in China, where Porsche Taycans will adhere to the GB/T standard. (Irritatingly, the sockets and connectors for the European and North American versions of CCS differ just enough that one region’s version can’t charge cars built to use the other.)
The CCS 2.0 specification, a superset of the SAE J1772 protocol and connector in North America, is designed to transfer up to 1,000 V into the vehicle—depending, of course, on the voltage its particular battery can accept. Porsche’s early tests suggested the weak point in existing EV hardware would be the charging sockets, which might not reliably tolerate such high voltages. So new components are required there, too.
Any Porsche model undergoes a sequence of performance improvements over its lifetime to keep customers engaged. The Taycan will be no different, Kramer says, hinting that more power from the battery to the motors is not only possible but likely.
“We can go higher,” he says, smiling. The challenge? “It becomes hard to drive” because it has so much power. Consider the Tesla Model S P100D, which is already capable of reaching 100 km/h in 2.3 seconds from a standing start. Even die-hard Porsche enthusiasts accustomed to very high levels of performance may find there’s a limit to their abilities to handle the power they crave—and to their passengers’ tolerance of the resulting g-forces.
Even ludicrous performance won’t sell an EV if buyers can’t conveniently recharge wherever they may want to go. Two years ago, a group of automakers in Europe (BMW, Daimler, Ford, VW Group) recognized the problem and set out to solve it.
In Western Europe, the result is the network of high-speed charging stations spreading fast under the Ionity brand. It was established in November 2017 as a follow-on to CharIN, a group of automakers and equipment makers formed to develop and promote use of the CCS fast-charging standard. Since 2018, the Ionity network has opened over 100 fast-charging stations toward its goal of 400 by 2020. At these stations, an electric-car driver can stop for 15 to 45 minutes and recharge a vehicle as fast as its onboard charger permits—all the way up to 350 kW.
The Porsche Taycan will also be the first vehicle launched with a feature called Plug and Charge (ISO 15118), a standard under which the vehicle identifies itself to the charging network so the driver doesn’t need to present a membership card or payment method. Instead, on the back end—with personally identifiable information shielded by layers of public-key infrastructure encryption—the network being used identifies the vehicle, its owner, and the payment method. Then it creates a transaction that’s seamlessly charged to the specified account.
The standard has to be incorporated into both the vehicle and the charging site, with back-end modifications to permit seamless roaming. The Ionity network in Europe will have it all integrated in time for the arrival of the first cars that can use it.
In North America, Electrify America (EA) is the only network so far that has announced it will include Plug and Charge. In May 2019, that network’s technical center in Herndon, Va., held a test day to give carmakers and charging-station manufacturers the chance to test their hardware via EA’s network to ensure compatibility. Similar efforts from other networks will follow over time. Indeed, North American networks have issued bilateral roaming and interconnection agreements regularly through the first half of 2019.
The roots of Electrify America date to September 2015, when the U.S. Environmental Protection Agency announced that VW Group had installed software in diesel vehicles that disabled emission controls on the road—that is, outside of EPA lab tests. The scandal, which involved about half a million vehicles sold in the United States from 2009 through 2015, overturned VW’s long-standing bet on diesel. That’s what led the company to embrace what it had only dabbled in: electric drive.
VW Group has so far allocated €30 billion to cover the costs of the diesel emissions scandal. The impact is global, also affecting 11 million diesel vehicles the company had sold in Europe. In a comprehensive settlement of multiple charges by various U.S. and state agencies, VW provided about $2 billion to establish a fund to provide zero-emission vehicle infrastructure in the United States, with 40 percent allocated to California. The funds were to be spent in four 30-month segments, with approvals by the EPA and the powerful California Air Resources Board required at each interval.
The result is the Electrify America charging network. The agreement states that by 1 July 2019, the network was to have more than 2,000 fast-charging cables in 484 discrete sites operating or under construction throughout the United States. The pace was rapid; its first station, in Chicopee, Mass., didn’t open until May 2018. Nevertheless, EA met the goal. (There’s an Electrify Canada too, separately funded.)
EV Car Predictions for 2040
Source: Bloomberg New Energy Finance 2018 Electric Vehicle Outlook
Though the EA network is a separate corporate entity, it is wholly owned by the Volkswagen Group of America, tying the company to its wholesale transition into battery-electric vehicles. It says it plans to build and sell 1 million of them a year by 2025, out of total global production of 10 million vehicles. Volkswagen asserts such plans were under way before the EPA scandal, but observers are skeptical.
That million-EVs-a-year figure can be deceptive for Americans, however. The bulk of those vehicles are likely destined for China, and to Europe thereafter. While VW plans to assemble a battery-electric compact crossover utility vehicle in Tennessee, starting in 2022, analysts suggest that North America will lag significantly in its adoption of battery- electric vehicles.
There are many reasons for the lag. One is that unlike Europe or China, the United States has more than 3,000 separate electric utilities, overseen by 50 state public-utility commissions. California, for instance, has more than 50 utilities, split among larger investor-owned companies, publicly owned providers, and rural electric cooperatives. That makes it hard to scale up the installation of charging infrastructure. By contrast, in many European countries Ionity was able to negotiate with only a single national electricity provider.
Another reason is that U.S. drivers drive farther, on average, than those in Europe, Japan, or China. Gasoline in the United States is cheap by global standards, and there is a dearth of mass transit between cities 300 to 500 km apart, a distance that is usually too short to fly economically.
Finally, North American automakers have yet to persuade the industry they’re fully on board with battery-electric vehicles. General Motors is by far the furthest along. Its CEO, Mary Barra, said in 2018 that GM expected to be able to sell electric vehicles with ranges of 320 km or more at a profit during the early 2020s. The company’s last new electric vehicle launched in December 2016, however, and its next all-new one isn’t expected until after 2020.
As for the others, Ford hasn’t introduced a new electric or plug-in hybrid vehicle since 2013. It says it will have a 300-mile (482 km) electric crossover utility for 2020. And Fiat Chrysler, perennially seeking a merger partner among the world’s automakers, has bigger challenges than electric cars.
U.S. automakers have declined to follow Tesla’s lead in setting up charging networks. Throughout its first several years of selling the Volt plug-in hybrid and Bolt EV electric car, GM said it had no intention of spending any money to provide charging infrastructure. A recent announcement that it would join Bechtel Corp. in a joint venture to do just that represents a change in tone, but the project’s scope and impact remain to be seen.
The biggest factor in the world’s electric-car race, however, is China. Its government has long wanted to dominate global supplies of lithium-ion battery cells, photovoltaic solar cells, and plug-in electric vehicles. In 2018, 1.2 million electric cars were sold in China, about 25 percent more than in the rest of the world combined. Total global vehicle sales number roughly 86 million.
GB/T, China’s own fast-charging standard, is currently specced at more than 200 kW and up to 1,000 V. In August 2018, the China Electricity Council agreed to partner with the Japanese CHAdeMO consortium for a standard, now known as ChaoJi, that can handle 900 kW.
But the country’s fast-charging infrastructure today is less developed than that in Europe and Japan, says longtime China hand and auto-industry consultant Michael Dunne of ZoZoGo.
“Chinese consumers are superpractical and frugal,” Dunne explains. “Many are happy to charge during the day at the office. Standard charging and free, or lower cost, is much preferred over fast charging but expensive.” He cites Tesla as the country’s current leader in fast-charging sites, with more than 250 Supercharger locations in China at the start of 2019.
Still, China is known for doing things at scale. It now has what is purported to be the world’s largest charging site, the Minle site in Shenzhen. In May, Southern Power Grid added another 172 fast-charging cables to bring the total to 637 fast-charging connectors that can charge up to 5,000 vehicles a day.
Tesla, Dunne notes, also understood that even wealthy Chinese buyers often live in apartment buildings. It set up urban Supercharger sites to allow them to recharge once or twice a week even if they don’t have a dedicated parking space where they live or work.
Porsche’s Kramer echoes that theme as well, suggesting that by 2025 or so, 350-kW fast charging will spread to less expensive and higher volume VW Group vehicles. That charging rate would similarly make electric cars practical for apartment dwellers in European cities even if they park at the curb, in public parking structures, or in open lots.
It tends to be more complex, time-consuming, and expensive to build high-voltage charging stations in urban centers than in the countryside. It would seem that the companies that are best placed to do it are the electric utilities that already serve those areas.
What role utilities might play in charging cars could be the subject of several articles. However, despite uninformed suggestions that electric-car charging demands may crash the grid, the utilities of the world are unfazed by the prospect of EV charging plazas drawing up to 2 megawatts from a few dozen stations.
A standard-issue big-box retail store—Walmart, say—requires up to 2 MW for things like refrigeration and lighting. No one raises the specter of thousands of Walmarts crashing the grid. Charging stations for EVs are designed and approved like anything else of size that gets built, and electric utilities know how to provide the required electric capacity to new construction. It’s what they do.
The role of utilities in building and operating charging sites themselves, however, varies considerably. For years, utilities in most areas outside early-adopter California watched EVs cautiously. Now, major U.S. utilities are recognizing that the market will come and that all types of charging offer a rare chance to increase their operations and footprint. Moreover, in many cases, their regulators may let them pass the costs of such expansion to consumers, a practice known as rate-basing, if they can demonstrate a public benefit.
Unsurprisingly, privately funded charging networks cry foul. A number of lawsuits have been filed over the past five years to block or modify submissions by utilities to set up charging networks in their service areas. By and large, especially in California, such operations are being approved—with strong provisos requiring installations in underserved communities that commercial operators may deem unprofitable.
When Porsche Taycans hit the road—late this year in Europe, early in 2020 in North America—they’ll be bought by affluent people, who generally own their own homes. That’s where they’ll charge the cars, for the most part. On long road trips, Electrify America and soon other providers—EVgo and ChargePoint are two—will provide very fast charging as needed, and their networks will expand in coming years to meet demand.
The question is whether there’s a business there. Or might EV charging be a necessary service that must be provided somehow to sell cars and cut carbon emissions? Electric-car advocates concluded years ago that there’s no business model in selling electricity via public 240-volt Level 2 charging stations. These seem likely to become ubiquitous over time. A good parallel might be Wi-Fi service at hotels and public spaces like airports: It’s often free, though providers will charge for it where they can.
The jury is still out on whether there’s a business model for DC fast charging. A rough benchmark seems to be that it shouldn’t cost much more per mile than gasoline. As analyst John Gartner of Navigant Research notes about the added costs of providing more electric supply to a site, “If it’s challenging to get cost recovery at 25 and 50 kW, what kind of utilization do you need to cover your costs at 150 or 350 kW?”
Still, these are early days, and lots of companies are trying lots of approaches. And consider the changes over the nine years that modern electric cars have been on sale.
Business analysts either scoffed or scratched their heads when Tesla first announced that it would build its own dedicated high-speed charging network in the United States and globally. But it did exactly that, and in just six years. As in so many other aspects of electric cars over the last decade, Tesla turns out to have been prescient.
The history of technology provides ample evidence that those who pioneer technology often don’t profit from it—or even survive. Whether or not Tesla remains an independent carmaker 10 years hence, it showed what was possible. The rest of the world is now following in its footsteps.
This article appears in the September 2019 print issue as “Porsche’s Fast-Charge Power Play.”