There’s no getting around it: The new GMC Hummer EV, which attracted a lot of attention at The Amelia concours in Florida March 6, is a heavyweight. According to test data, the Edition 1 tips the scales at 9063 pounds, with about a third of that (2923 pounds) in the battery pack alone. The pack weighs more than a Honda Civic sedan.
To give the beefy premium 1000-horsepower Hummer more than 350 miles of range and big eye-catching acceleration, a huge 210-kilowatt-hour (kWh) battery pack was required. It’s a long way from the late Lotus founder Colin Chapman’s memorable phrase, “Simplify, then add lightness.”
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GM declined to comment, but Carlos Tavares, CEO of Stellantis, said in a telephone interview that it’s a “valid” point that cars should be lighter. “It’s more difficult to drive heavy cars,” he said. “The other issue has to do with scarce raw materials [that are slowing down auto production]—it takes more of those materials to make bigger cars. So, yes, we need to make cars lighter, so that they will use less energy. Lighter electric cars won’t have to carry such big batteries, and will have shorter charging times.”
Just because the obvious solution is to get to smaller packs by reducing vehicle weight with downsized components and lightweight materials such as carbon fiber or aluminum, don’t expect the industry to necessarily move decisively in that direction. Price is a consideration. Americans like their big cars (including Hummers), and some industry insiders argue that the critical sustainability issues will actually move elsewhere.
Jim Motavalli
Anthony Schiavo, research director at Lux Research, is author of the report Electric Vehicle Lightweighting 2030, which predicts that battery pack densities will increase by 15 percent in the next decade. “Battery performance, energy density, and cost have improved very dramatically, which reduces the cost penalty of bigger battery packs,” Schiavo said in an interview. “We’re around $100 to $120 per kilowatt hour now. A key conclusion for automakers is that the way to increase range is by using bigger packs, not a ton of very expensive carbon fiber and advanced composites—the hallmark of early cars such as the BMW i3.”
Schiavo says we shouldn’t judge EVs by old environmental metrics. “Obviously, a 9000-pound Hummer is not sustainable, and it’s not the kind of vehicle you should be using to pick up the groceries,” he said. “But these are EVs, without the tailpipe pollution issues inherent to internal combustion. I think important considerations for future designs will be lighter weights for cost reduction—using cheaper and thinner materials—and material sourcing. Did the material come via unsustainable mining operations or from conflict areas?”
“Yes, we need to make cars lighter, so that they will use less energy.”—Carlos Tavares
Although it’s moribund now, Schiavo think that the kind of EV battery swapping proposed by the now-defunct Better Place might return. “It’s coming into its own in China for fleets via companies like Nio,” he said. “We expect to see more swapping, especially if one brand of EV becomes dominant in sales and there’s some battery standardization in the industry.”
Still, automakers can and will try to reduce the weight of their electric vehicles. John Catterall, vice president of the automotive market for the American Iron and Steel Institute, acknowledged that improvements in battery technology may reduce the need for lightweighting. But in an interview he said that high-strength steel for products like battery carriers “will mean that automakers can get away with thinner materials that can take a higher load. We have to work to get the mass down on EVs, and reductions of 25 percent are possible in cars that use high-strength steel.”
GMCGMC
Those battery carriers could also be made of thermoplastic resin, said Matt Zessin, automotive market manager at M. Holland Company, which distributes such products. “EVs are relatively new in our market,” he said in an interview. “But batteries are a main component in the weight of the vehicle. We’re looking at the whole landscape, including the trays and covers.” The specific solution is glass fiber mixed with polypropylene, which is already used in instrument panels and center consoles, he said.
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Carbon fiber, seen in many EVs, has huge weight advantages, but Zessin said “the issue has been getting carbon fiber to a price point that makes sense for the market.” Carbon fiber certainly makes sense on high-end electric supercars, and for certain parts. Carbon Revolution, for instance, is an Australian wheelmaker that has supplied Ford (including for Shelbys), Ferrari and General Motors (the Corvette Z06). The company says it has six programs in production with three global companies, and another nine programs in development. On electric SUVs and pickups, it said, “very meaningful range extension benefits” are possible.
In the April issue, Consumer Reports charted the range of current EVs, with the Lucid Air Grand Touring at the very top, 516 miles on a charge. The closest competitor was the long-range version of the Tesla Model S, with 405. The Grand Touring’s battery pack is 112 kWh, big but not the largest on the market. The Tesla’s pack is only slightly smaller, at 100 kWh. The Hummer EV’s 210 kWh yields 329 miles—a result partially explained by the vehicle’s weight. So what is Lucid’s secret?
Lucid Motors
Eric Bach, senior vice president for product and chief engineer at Lucid Motors, told Autoweek that getting more miles out of a battery pack with a given amount of stored energy has a number of dimensions. “Our 0.20 drag coefficient is world class, and we have a small frontal area on the Air,” he said. “We have low rolling resistance in our proprietary tires, in every bearing, and in the whole system. And we lightweighted the drivetrain unit, which includes the motor, differential, gearbox and inverter. It weighs only 74 kilos [163 pounds]. Tesla’s unit in the Model 3 weighs 92 kilos [202 pounds], 30 percent heavier and less powerful. And then there’s our overall effort to make the whole car as light as possible.”
The Grand Touring is no lightweight—it hits the scales at 5266 pounds. Most EVs are heavy, and aren’t going to please Colin Chapman anytime soon. Batteries are still a big load to carry, but automakers are using every means at their disposal to build efficient cars around them.
Share your thoughts on all things EV, battery packs, and the relative heftiness of both in the comments below.
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