The truck is powered by a giant battery under the cab. It has two rear axles, each outfitted with two electric motors, one for each wheel. Because the truck has no engine or transmission, Tesla says it has far fewer moving parts than a diesel truck and will require much less maintenance.
In briefings before the event, Tesla declined to disclose critical information about the truck such as its price and its driving range between charges. A Tesla official said the company hoped to offer a production version for sale by the end of 2019.
For an electric semi truck, battery range remains a significant question mark. Analysts at Bernstein, an investment bank, estimated that Tesla’s truck would be able to travel 300 to 450 miles a day before needing to recharge its battery pack, while most long-haul trucks cover 500 to 600 miles in a day.
“We see 300 to 450 miles a day as a significant constraint,” the bank said in a research report.
Tesla is taking on the challenge of electric trucks while struggling with a number of issues in its car business. The company recently introduced its most affordable car, the Model 3, but has run into delays.
When Model 3 production started in July at Tesla’s plant in Fremont, Calif., Mr. Musk said he hoped to increase output to 20,000 vehicles a month by December. But Tesla had assembled just 260 by the end of September.
In a letter to shareholders two weeks ago, Mr. Musk said he hoped to lift production to 5,000 a week early next year. And last month the company fired several hundred workers for what it said was substandard performance, raising further concerns about its ability to meet Mr. Musk’s aggressive manufacturing goals.
The Model 3, with a starting price of $35,000, is intended to become Tesla’s top-selling car. The company’s other vehicles — the Model S luxury sedan and the Model X, a sport utility vehicle — sell for $70,000 and up. Last year, Tesla made about 85,000 vehicles, and is on track to make about 100,000 this year.
Because the Model 3, with its lower price, will appeal to a wider class of consumers, Mr. Musk is hoping to push sales to more than 500,000 cars in 2018.
So far the company has attributed the slow pace of Model 3 output to difficulties in producing battery packs at its Nevada plant, called the Gigafactory. It also said welding processes and final assembly tasks in the Fremont factory were moving more slowly than other parts of the manufacturing system.
“I think the electric, autonomous truck market is a very promising proposition,” said Michelle Krebs, an analyst at Autotrader.com. “One of my concerns with Tesla is they have way too much on their plate. They can’t overpromise and underdeliver on a truck.”
The strain of starting up Model 3 production has taken a toll on Tesla’s bottom line. In the third quarter, the company lost $619.4 million, even as revenue from auto sales increased 8 percent to $2.08 billion.
Aside from running Tesla, Mr. Musk heads the rocket company Space X and a new venture, the Boring Company, which aims to build tunnels for futuristic pods that can carry people at speeds of up to 700 miles per hour.
Competitors have already begun testing electric trucks and self-driving technology. Last month, Daimler demonstrated an electric tractor-trailer. Embark, a Silicon Valley start-up, said this week that it had begun using self-driving trucks to transport Frigidaire refrigerators from a warehouse in El Paso to a distribution center 650 miles away in Palm Springs, Calif.
While Tesla jumped out ahead of established automakers with its electric cars and technologies like its Autopilot semiautonomous driving system, it faces a much different landscape in trucks, Ms. Krebs said.
Tesla doesn’t have experience in the truck market, and it is up against formidable competitors, like Daimler, that have a built-in customer base, she said.
“The critical thing with trucks is that it is a work tool,” she added. “It has to work all the time. It’s not like a sports car and I have something else in the garage to drive if it’s in maintenance or whatever.”