Tesla CEO blames Model S fire on impaled battery

SEATTLE Tesla CEO Elon Musk said a battery fire this week in one of the electric car maker's vehicles was caused by being impaled by a metal object during an accident.

Musk said in a blog post on Friday that a curved metal component was apparently the culprit in causing a Tesla Model S to catch on fire Tuesday. He says the object's shape led to a powerful hit on the underside of the vehicle, punching a 3-inch hole through an armor plate that protects the car's bottom.

Musk also said the car's design helped prevent the fire from spreading to other parts of the vehicle.

"A fire caused by the impact began in the front battery module -- the battery pack has a total of 16 modules -- but was contained to the front section of the car by internal firewalls within the pack. Vents built into the battery pack directed the flames down towards the road and away from the vehicle," he wrote.

Tesla says the car properly contained the blaze. The driver was able to exit the highway in the Seattle suburb of Kent before flames engulfed the front of the vehicle.

Tesla shares fell more than 6 percent Wednesday and continued to skid the following day after a video of the burning Model S surfaced on automobile site Jalopnik.com. The stock rebounded today to close at $180.98, up 4.4 percent on the day. 

Musk wrote that fires are more common in conventional gas-powered vehicles.

"For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery than a large tank of highly flammable liquid," Musk said.