Volt Spokesman Says Battery Reports Off The Mark

By Scott Doggett December 10, 2011

Since the U.S. National Highway Traffic Safety Administration issued a statement Nov. 25 announcing that it would investigate the risk of fire in crashed Chevy Volts, numerous contradictory reports have appeared in the media relating to the problem and to General Motors' response to it. In an interview with AutoObserver this week, Rob Peterson, the model's top spokesman, went to lengths to set the record straight, beginning with a description regarding what is and what isn't known concerning sparks and/or fire that originated in three Volt batteries following laboratory crash testing.

Volt Spokes Mark lede.jpgIn the November statement, the NHTSA said that on May 12 of this year it performed a side pole impact test (left), followed by a post-impact rollover test on a Volt. In connection with that testing, the agency identified "the potential for intrusion damage to the battery which may result in a substantial thermal reaction and fire." Twenty-one days after the May 12 test, heating inside the battery caused a fire that consumed the vehicle and three others near it. During the week of Nov. 14, the NHTSA performed three tests simulating the mechanical damage to the battery pack observed from the May incident. In one instance, sparks and smoke resulted. In another, the battery erupted in flames a week after the test.

Agency and GM engineers have been working to understand the precise cause of the sparks and fire and thus far have concluded that a daisy chain of events was responsible, most likely beginning with a rupture of the battery structure that allowed coolant to mingle with individual cells, Peterson said. "You have coolant that's getting into the pack and then resting on certain components and crystalizing. What happens next is what we're trying to determine," he said. He denied media reports that suggested the fires could have resulted from a chemical reaction between coolant and lithium stored within cells.

Frank Borris, the NHTSA's defects investigation chief, on Tuesday sent a memorandum to the agency's vehicle research test center, asking it to inspect the five Volts it possesses and "take photographs of the floorpan/crossmember near the battery tunnel on both the driver and passenger sides of the vehicle." In the memo, he wrote: "The objectives of this test program are to document if any changes in the welding process are visible at the area of intrusion." The NHTSA has no reports of real-world fires. Meanwhile, a House committee intends to a hold a hearing next month on why the agency waited five months before publicizing the initial Volt fire.

Nissan: It's A Volt Thing
Although reluctant to say something similar could never happen to a Leaf battery-electric vehicle, Nissan's U.S. product safety director told AutoObserver in a recent interview that the conditions that appear to have caused the Volt's post-collision problems simply don't exist in the Leaf. Like the Volt's, the Leaf's battery is enclosed in a damage-resistant steel case and surrounded by a crash safety structure that's separate from and located inside the car's overall crash safety protection zone. "It's a three-layer system," said Nissan North America product safety and environmental director Bob Yakushi.

The Leaf has an automated system that senses a high-impact crash and disconnects the high-voltage pack in the event of a crash. That's important because, unlike the Volt, the Leaf battery doesn't use an active thermal control system. Instead, Nissan relies on the Leaf battery's inherent low operating temperature and ambient air that's blown through the pack to regulate pack temperatures. Thus there are no internal cooling lines to break and leak fluid that could short a damaged battery or interact with exposed lithium, and no internal electronics to initiate a spark-causing short.

Peterson said the Volt's on-board electrical energy becomes isolated in the battery (cutting off power to the rest of the car) upon airbag deployment or when the vehicle's sensors sense a significant crash. However, "you cannot discharge a battery upon crash. An electrical load must be used to deplete the energy from the battery," he said. "This goes for all batteries." Presumably the risk of fire would be eliminated or greatly diminished if the battery could somehow be discharged automatically and safely following a serious crash.

Peterson was quick to point out that unlike the Leaf, the Volt is equipped with a communications system that will notify GM of a crash almost immediately after it's occurred. But it's kind of an irrelevant point, given that the sparks and fire in Volt batteries occurred days later. Also, while the subscription-based OnStar communications service is provided free of charge to Volt customers for the first three years of ownership, after that it is discontinued unless the owner opts to pay for it.

No Buy-Back Program
GM Chairman and CEO Dan Akerson was quoted by The Associated Press earlier this month as saying that the automaker would buy Volts back from any owner who is afraid his or her plug-in hybrid might catch fire. Multiple blogs and other news entities have since reported that GM has initiated a Volt buy-back program. The automaker has done no such thing, Peterson said. "If a customer wants to sell their Volt back to us, we'll consider that on a case-by-case situation. It is not a formal initiative as it was originally reported," he said.

However, GM has initiated a loan program for Volt buyers, and to date about 30 of the more than 6,000 in the United States alone have opted to borrow a GM model, Peterson said. Some of those are Volt owners with legitimate concerns about their cars, he said. "There are also guys that are encouragingly are saying, this is an opportunity for me to test drive a different GM product. And then there's a third group we've heard from that said, hey, I love my Volt, unfortunately I'm a little bit over miles on my lease. I'm going to take advantage of the loaner program and use it to kinda protect myself" (from putting exceeding the mileage limitation of their Volt lease agreement).

"We stand solely behind this car," Peterson said. He said GM is providing Volt owners with good transparency with what's happening from a NHTSA perspective and from a customer-satisfaction perspective. "We're saying if you have any concerns whatsoever, give us a call." As for several media reports that GM is designing a new battery for the Volt, Peterson said, "We're going to do what's right by the customer. If that requires us to redesign the battery pack, we'll redesign the battery pack. If we're asked to, we will. But we're not being asked to."

AutoObserver Senior Editor John O'Dell contributed to this story.

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