A Tesla Model S electric car caught fire this week after hitting debris on a Tennessee freeway, the third fire in a Model S in the past five weeks.
The blaze on Wednesday afternoon near Smyrna, Tennessee, engulfed the front of the car. A Tennessee Highway Patrol spokeswoman said the Model S ran over a tow hitch, which hit the undercarriage of the car, causing an electrical fire.
It is the second Model S blaze involving road debris. Last month, a driver near Seattle, Washington, hit debris that pierced a shield and the battery pack, causing a fire. In the other fire, a driver in Mexico crashed into a concrete wall and a tree at a high speed.
Shares of the Tesla Motors Inc, based in Palo Alto, California, fell 7.5 percent to US$139.77 on Thursday. That decline came after Wednesday’s plunge of 14.5 percent, after concerns about a battery shortage, as well as the costs the carmakers will incur as it builds more cars, spooked some investors. The stock is still up 312 percent this year.
The Model S has as a large battery pack under the passenger compartment, protected by a 6.33cm metal shield. Experts say that if debris punctures the shield and damages the battery, it can cause shorts and arcing that can touch off fires.
The US National Highway Traffic Safety Administration said the agency will contact Tennessee authorities to determine if there are safety problems that need further action. The auto safety watchdog decided last month not to investigate the Seattle-area fire, saying there was no evidence it was caused by a safety defect.
The driver in Tennessee was able to pull onto an emergency lane and escape. Tesla said it has sent a team to investigate.
Company spokeswoman Liz Jarvis-Shean has said the fire was not spontaneous. She said Tesla contacted the driver, who believes the car saved his life. Tesla CEO Elon Musk has said that the design of the Model S is safer than that of a car with a conventional fuel tank.
The fire burned the front of the car, according to pictures posted on the Jalopnik.com and Valuewalk.com Web sites.
Rutherford County Fire Department chief Larry Farley said the blaze was so hot and intense that it melted the front of the car.
“It pretty much just melted to the road,” Farley said.
The passenger compartment was in pretty good shape after the flames were extinguished, Farley said. A Fire Department report estimated the value of the loss from the fire at US$120,000.
According to the US Fire Administration, there are around 194,000 vehicle fires on US roads each year. The vast majority — 61 percent — start in the engine area, while 15 percent start in the passenger area.
General Motors Co (GM) and Nissan Motors Co Ltd make the top-selling electric cars in the US, the Volt and Leaf. Neither knows of any real-world blazes in those vehicles. A Chevrolet Volt caught fire two years ago after a government crash test, but the government closed an investigation into the incident after GM agreed to a safety campaign to bolster shielding around the battery.
GM has sold more than 50,000 Volts in the US since late 2010, while Nissan has sold almost 38,000 Leafs. Tesla has sold an estimated 16,251 Model S cars in the US, according to Autodata Corp.
The Model S, which starts at US$70,000, can go up to 425km on a single charge.