What automakers are studying about electrical autos, veterans of Weight Watchers already know: It is onerous to maintain the kilos off as soon as you have misplaced them.
EVs are posting eye-popping curb weights, wiping out the lightweighting progress automakers have made up to now decade. The heavy batteries required to supply lots of of miles of vary are the perpetrator. The battery pack within the GMC Hummer EV pickup and SUV weighs 2,818 kilos — simply 52 fewer kilos than the complete curb weight of the Chevrolet Cruze, the compact sedan that ended manufacturing in 2019.
No higher instance of the car weight-reduction plan yo-yo will be discovered than the previous king of lightweighting, the aluminum-bodied Ford F-150.
The 2012 steel-bodied F-150 SuperCrew 4×4 pickup sported a curb weight of 5,586 kilos. An aluminum model changed it in 2015, shaving roughly 700 kilos. But right this moment’s electrical F-150 Lightning SuperCrew ranges from 6,015 to six,893 kilos relying on the battery pack — as a lot as 1,307 kilos greater than the steel-bodied pickup.
And that is svelte in contrast with different so-called mild vehicles.
The Hummer pickup and SUV lead the EV league with a curb weight over 9,000 kilos — practically 2,000 kilos greater than the gargantuan unique diesel-powered Hummer H1. Basic Motors’ electrical Chevrolet Silverado, GMC Sierra and Cadillac Escalade IQ — which share the Hummer’s underpinnings — are additionally super-heavyweights at round 8,500 kilos.
The huge horsepower and torque from electrical motors enable EVs to really feel lighter than they’re. However these added kilos restrict driving vary and create security issues.
A Nationwide Bureau of Financial Analysis research discovered that an additional 1,000 kilos will increase the prospect of crash fatalities by 47 p.c. Different research have discovered that heavy EVs are growing air pollution by inflicting tires to shed tiny rubber particles.
Specialists say reducing the burden of EVs can be far harder than the combustion engine car weight-reduction plan craze. Most EVs have already got some aluminum physique parts and different light-weight supplies, proscribing avenues for weight discount.
“It is a vicious cycle,” stated Sam Abuelsamid, e-mobility analyst at Guidehouse Insights. “If in case you have a 9,000-pound car versus a 6,000-pound car, you want greater brake rotors and calipers. You have additionally received to have heavier wheels and tires because the car goes up in weight.”
Apart from the heavy batteries, EVs have gained weight as a result of they’re over-engineered for security, in keeping with specialists.
“Nobody needs to have a hearth, and nobody needs a car that is not crashworthy,” Detroit teardown and value guru Sandy Munro advised Automotive Information. “There’s over-engineering, and it is being performed to make sure that if one thing does go improper that lives will not be in jeopardy.”
A decade in the past, automakers plowed billions of {dollars} into reducing car weight to satisfy ever-tightening gasoline financial system and emissions requirements.
Ford Motor Co. made the largest powertrain funding in its historical past when it rolled out the EcoBoost line of turbocharged engines to exchange larger-displacement engines.
Many different automakers additionally downsized and boosted their engines. They began utilizing aluminum physique panels and structural parts product of carbon fiber and magnesium.
GM lower weight by adopting a mixed-materials manufacturing technique, using the lightest, strongest metals in strategic areas in a lot of its largest autos. BMW and Toyota invested closely in carbon fiber. And practically each automaker turned to 3D printing to design light-weight components.
Nevertheless it is not simply the burden of the EV battery pack that is placing the kilos again on.
The addition of superior electronics that allow automated-driving options — lidar, radar, cameras, sensors and the computer systems that run them — has contributed as properly. A number of screens, two and three electrical motors and all-wheel-drive techniques additionally add kilos.
That does not depart a lot in the way in which of low-hanging fruit on a car’s physique or powertrain for automakers to cut back curb weight, Munro stated.
“For those who have a look at the skateboard chassis and squint, it appears to be like quite a bit like a body-on-frame with a prime hat,” he stated. “There’s not a lot we are able to actually do to cut back weight while you transfer to a skateboard, which has to have fairly a little bit of structural integrity as a result of it’s carrying the load.”
The most important alternative to chop the burden of an EV resides in its batteries and within the metal or thick aluminum enclosures that home them.
Enhancements to battery chemistry and packaging of the enclosure will cut back weight, stated Royston Jones, chief know-how officer at Altair Engineering. The body-in-white, or skeletal, buildings of EVs can also weigh much less, he thinks.
Automakers will make weight reductions as soon as they’ve a greater thought how EVs carry out in real-world crashes and as they research how customers are utilizing them, Jones stated.
“I feel there’s a lengthy option to go along with design optimization, the place the entire construction is considered,” he stated.
No less than one automaker has already began that course of. The highest of the battery pack enclosure can also be the floorboard that mounts the seats on some configurations of the Tesla Mannequin Y. On most different EVs, the battery enclosure is an entire meeting underneath the floorboard.
However it’s the battery cells themselves by which a lot of the burden might come out of future EVs. In most of right this moment’s EVs, cells are spaced aside to cut back hearth danger ought to one cell overheat or the battery enclosure turn out to be broken in a crash. If automakers might safely pack cells nearer collectively, they might shrink and lighten the dimensions of the pack with out dropping vary.
“For those who open up present battery packs, you may discover you could have a field inside a field with cells within the internal field,” Abuelsamid stated. “The draw back of that modular structure is there’s loads of wasted area.”
One battery chemistry with the potential to cut back wasted area is lithium iron phosphate. These cells will not be lighter than right this moment’s lithium ion cells, however they’re far much less vulnerable to fires attributable to overheating and crashes. Lithium iron phosphate might allow main weight-saving modifications: Cells may very well be packed nearer, and cooling techniques may very well be smaller, enabling the enclosures to weigh much less.
Our Subsequent Vitality, the Novi, Mich., startup, is growing lithium iron phosphate cells for EVs that may very well be packaged in light-weight carbon fiber enclosures with out affecting security, stated Sam Haberl, vp of automotive enterprise growth for the corporate. The cells themselves might additionally play a task in structural rigidity.
“One other factor we’re growing at Our Subsequent Vitality is structural cell-to-pack, utilizing the cells as a compressed honeycomb that creates the power of the pack itself, and that minimizes the necessity for different supplies,” Haberl stated.
The corporate has contracts with BMW and several other industrial fleet EV makers.
The weightiness of EVs has one other consequence. Increased EV weights are inflicting sticker costs to extend as a result of automakers are utilizing extra uncooked supplies within the bigger tires and greater brakes, for instance.
Ned Curic, Stellantis’ chief know-how officer, advised Automotive Information Europe that the state of affairs “just isn’t good for the setting, it is not good for assets, it is not good for effectivity.”
“It frustrates me,” he stated, “that each one of our automobiles — for the business as a complete — are simply too heavy. The associated fee is turning into unaffordable for the center courses.”