Updated

The leader of upstart automaker Tesla Motors is confident that its Model S car is safe and will be cleared by a federal investigation into two battery fires.

CEO Elon Musk said the fires, which occurred when metal road debris pierced the underbody of the cars at highway speeds, are extreme cases. He doesn't expect a recall and said his engineers are not working on any fixes for the battery-powered cars.

"In both cases it was a large piece of metal essentially braced against the tarmac," Musk said in an interview Friday with The Associated Press.

No one was hurt in the fires, which happened along freeways near Seattle and Nashville, Tenn. starting Oct. 1. Another fire happened in Mexico after the driver ran through a concrete wall at more than 100 mph.

Musk said no one has ever been hurt in a Model S crash, which shows there's no safety problem for drivers or passengers. The only other reason to investigate is economic loss from the fires, but that's not an issue because Tesla amended its warranty to cover fire loss in crashes, Musk said.

"I'm not saying it can't happen again," he said. "I'm saying in any kind of low-speed impact, you're fine. Any car, Model S or not Model S, the underside is going to get significantly damaged if you drive over a large metal object."

Musk described the weeks since the fires as "torture." He said the crashes have received an unreasonable amount of media attention given that no one was injured. He understands that a new technology such as electric cars will get more scrutiny, "but not to the insane degree that we're receiving."

Tesla's stock price has dropped by 37 percent since the first fire. Some investors and analysts also were disappointed by the company's third-quarter results.

But Musk said the stock's value, which earlier in the year had risen 470 percent to $194.50, got too high and the market is correcting it. "I believe I said several times that the valuation was more than we had any right to deserve," said Musk, a billionaire who co-founded PayPal and started SpaceX. "I was not the one who thought the valuation should go up to such levels."

Tesla shares closed Friday down 72 cents, or 0.6 percent, at $121.38.