Heavier EVs are causing safety and pollution problems

A decade ago, automakers plowed billions of dollars into cutting vehicle weight to meet ever-tightening fuel economy and emissions standards.

Ford Motor Co. made the biggest powertrain investment in its history when it rolled out the EcoBoost line of turbocharged engines to replace larger-displacement engines.

Many other automakers also downsized and boosted their engines. They started using aluminum body panels and structural components made of carbon fiber and magnesium.

GM cut weight by adopting a mixed-materials manufacturing strategy, employing the lightest, strongest metals in strategic locations in many of its largest vehicles. BMW and Toyota invested heavily in carbon fiber. And nearly every automaker turned to 3D printing to design lightweight parts.

But it isn’t just the weight of the EV battery pack that’s putting the pounds back on.

The addition of advanced electronics that enable automated-driving features — lidar, radar, cameras, sensors and the computers that run them — has contributed as well. Multiple screens, two and three electric motors and all-wheel-drive systems also add pounds.

That doesn’t leave much in the way of low-hanging fruit on a vehicle’s body or powertrain for automakers to reduce curb weight, Munro said.

“If you look at the skateboard chassis and squint, it looks a lot like a body-on-frame with a top hat,” he said. “There’s not much we can really do to reduce weight when you move to a skateboard, which has to have quite a bit of structural integrity because it is carrying the load.”

The biggest opportunity to cut the weight of an EV resides in its batteries and in the steel or thick aluminum enclosures that house them.

Improvements to battery chemistry and packaging of the enclosure will reduce weight, said Royston Jones, chief technology officer at Altair Engineering. The body-in-white, or skeletal, structures of EVs also can weigh less, he thinks.

Automakers will make weight reductions once they have a better idea how EVs perform in real-world crashes and as they study how consumers are using them, Jones said.

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