Enlarge / This image shows the Uni Wheel concept in three different stages of articulation. (credit: Hyundai)

We like weird new engineering ideas here at Ars, and today we have a particularly interesting one in the realm of electric cars. It's called the Uni Wheel, and it has been designed by Hyundai and Kia as a way to revolutionize the layout of an EV powertrain to more efficiently use space. In fact, the automakers say it's not just for cars—the new drive system works with wheel sizes as small as four inches to as large as 25 inches.

For EV enthusiasts of a certain bent, there's something a little inefficient about the way virtually every EV powertrain is laid out.

Not the battery in the middle, though—while it's bulky and raises the overall height of EVs, it makes sense for weight distribution, although people working on structural carbon-fiber batteries have some different ideas about that. The problem is the EV drive unit, a bulky thing that contains the electric motor, some gearing, and usually some power electronics. These take up room between the axles and have to be packaged around.

Enlarge (credit: Getty Images )

Today, the US Department of Energy published a notice of proposed rulemaking that would change the way the government calculates the energy efficiency of electric vehicles. If adopted, the changes will substantially downgrade the fuel-efficiency ratings given to EVs and be used to determine corporate average fuel economy (better known as CAFE). That might have serious implications for automakers, but don't worry—the consumer-facing MPGe and kWh/100 miles numbers you see on Monroney window stickers and at the US Environmental Protection Agency's fueleconomy.gov site won't change.

They call it CAFE, but you can’t drink it

Congress enacted CAFE in 1975 in the wake of the country's first serious energy crisis. It gives an average fuel efficiency number that each automaker must achieve to not be sanctioned by the government, and the standards and penalties are enforced by the National Highway Traffic Safety Administration.

But the fuel efficiency numbers that NHTSA calculates are much higher than the actual efficiency you or I might experience, or the numbers posted by the EPA for consumers to make buying decisions.

Enlarge (credit: George Rose via Getty )

Electric vehicle batteries keep getting larger, and the typical driving range between charges keeps growing.

The shift is partly a response to “range anxiety”—the fear of being stranded because EV batteries don’t have enough power to get to the next charging station—an idea so familiar in discussions of electric vehicles that it was spoofed in a Ram Super Bowl ad last month.

But this concern is unwarranted for a large share of EV customers, according to research from the University of Delaware, published February 21 in the journal Energies .

Enlarge (credit: GETTY IMAGES)

Building more EVs is a start, but the automotive industry needs to rapidly decarbonize its supply chains if it wants to stand any chance of meeting the 1.5˚C climate goal, according to a new study conducted by the consulting company Kearny on behalf of EV startups Polestar and Rivian. "Car companies may be on different paths when it comes to brand, design, and business strategies, and some won’t even admit that the road to the future is electric. I believe it is, and that the climate crisis is a shared responsibility—we must look beyond tailpipe emissions," said Fredrika Klarén, Polestar's head of sustainability.

Around the world, electric vehicle adoption is accelerating. EV sales in 2021 were already strong enough to cause the International Energy Agency to declare them a rare bright spot in terms of decarbonization, and 2022 saw sales accelerate by 55 percent year-on-year . Battery EVs accounted for almost 10 percent of all new light passenger vehicle sales last year, with nearly 7.7 million deliveries.

As automakers replace old internal combustion engine models with new BEV versions, the companies' corporate carbon footprints should shrink. As we explored last year , it only takes about two years for a BEV to beat a gasoline-burning car in terms of carbon footprint, as the BEV's vastly better efficiency overrides the fact that it's more energy-intensive to build.

Enlarge / A technician removes a battery cell from a testing vault at the "Volkswagen Group Center of Excellence" battery cell research center in Salzgitter, Germany, on May 18, 2022. (credit: John MacDougall/Getty )

How much does an electric vehicle’s battery performance change in hot weather? How about cold?

If someone drives aggressively in an EV, how does that affect the battery life?

How much do variations in battery materials make a difference in how an EV performs in various conditions?

Enlarge / The extremely aerodynamic Mercedes EQS 580 (credit: Eric Bangeman)

Mercedes-Benz first gave us a glimpse at its electrification strategy in 2018, with its first battery-electric vehicle—the EQC 400 crossover —going on sale in Europe in 2019. Sporting a range of around 220 miles, (354 km) the 402 hp (296 kW) SUV never made it over to this side of the Atlantic. The US instead got a pair of EQS sedans that went on sale in 2021: the $102,310 EQS 450 and the $125,900 EQS 580.

The EQS 580 4Matic is the heftier of the two models—it has more motors, more mass, and more horsepower. And don't mistake it for an S-Class sedan with all of the internal combustion bits swapped out for batteries and motors. The EQS is a new vehicle architecture designed from the beginning to push electrons, not hydrocarbons. And those electrons will push the EQS 580 a very long way—340 miles (547 km), to be exact.

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  Mercedes used the front of the EQS 580 to show how fond it is of its logo. There's no frunk above the plethora of three-pointed stars. [credit: Eric Bangeman ]

You can't get that far in an EV with a massive battery pack, and the EQS 580 has 107.8 kWh of juice at its disposal (the battery actually has a capacity of 120 kWh, about 10 percent of which is off-limits for driving). But what's truly impressive about this electric sedan is an absurdly low drag coefficient of 0.20, which is unmatched by any production BEV. It looks sleek, but at first glance, the profile isn't that much different from an S-Class sedan. Upon closer examination, you'll notice the longer wheelbase and a pop-open slot on the front quarter-panel, which is another clue to its aerodynamic profile. That slot is for adding wiper fluid, because not only does the EQS 580 have no frunk, the hood does not even open.

Enlarge / A 2021 VW ID.4, the brand's battery-electric crossover. (credit: Jonathan Gitlin)

Volkswagen, the world’s second-largest electric vehicle manufacturer by volume, has “sold out” of battery-powered models in the US and Europe for this year as persistent supply chain bottlenecks hit global production.

The Wolfsburg-based group, which includes brands such as Porsche, Audi and Škoda, sold more than 99,000 electric models worldwide in the first three months of 2022 as it was hit by a shortage of semiconductors and wiring harnesses made in Ukraine.

Market leader Tesla delivered more than three times that number in the same quarter.