Tesla Inc’s newest promises break the laws of batteries

Bloomberg

Elon Musk knows how to make promises. Even by his own standards, the promises made while introducing two new Tesla vehicles—the heavy-duty Semi Truck and the speedy Roadster—are monuments of envelope pushing. To deliver, according to close observers of battery technology, Tesla would have to far exceed what is currently thought possible.
Take the Tesla Semi: Musk vowed it would haul an unprecedented 80,000 pounds for 500 miles on a single charge, then recharge 400 miles of range in 30 minutes. That would require, based on Bloomberg estimates, a charging system that’s 10 times more powerful than one of the fastest battery-charging networks on the road—Tesla’s own Superchargers.
The diminutive Tesla Roadster is promised to be the quickest production car ever built. But that achievement would mean squeezing into its tiny frame a battery twice as powerful as the largest battery currently available in an electric car.
These claims are so far beyond current industry standards for electric vehicles that they would require either advances in battery technology or a new understanding of how batteries are put to use, said Sam Jaffe, battery analyst for Cairn Energy Research in Boulder, Colorado. In some cases, experts suspect Tesla might be banking on technological improvements between now and the time when new vehicles are actually ready for delivery.
“I don’t think they’re lying,” Jaffe said. “I just think they left something out of the public reveal that would have explained how these numbers work.”
Here are four of Tesla’s most provocative battery claims—and an attempt to puzzle out how they might be achieved.
When Musk took the stage in an airport hangar in Hawthorne, California, his first proclamation was the Tesla Semi’s range: A fully-loaded truck would be able to travel at highway speeds for 500 miles.
The previous record-holder, unveiled by Daimler in October, is a truck that maxes out at 220 miles.
A heavy-duty, long-range truck is the toughest vehicle to electrify while still turning a profit, said Menahem Anderman, president of Total Battery Consulting Inc., in Oregon House, California. Tesla may be doing it to prove a point. “If you can make a semi truck with batteries,” Anderman said, “then you can make everything else with batteries.”
Tesla is making its trucks more efficient by reducing wind drag to levels that are comparable to those of sports cars. But even if Tesla achieves record-breaking efficiency for the truck, it would still require a battery capacity somewhere from 600 kilowatt hours to 1,000 kilowatt hours to deliver on Musk’s claims, according to estimates from Bloomberg New Energy Finance. Split the difference, at 800 kWh, and it would mean a battery that weighs more than 10,000 pounds and costs more than $100,000—even before you build the truck around it. Tesla has priced the truck with 500-mile range at $180,000.
One thing Tesla has going for it is the falling price of batteries. Musk may be banking on battery improvements between now to the early 2020s in order for its truck to make financial sense. The first Tesla Semis won’t hit the road until late 2019; even then, production would probably start. Most fleet operators will want to test the trucks before considering going all-in.