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  (Source: blogspot.com)
NHTSA says it is too soon to recall vehicles or parts

As promised, the National Highway Traffic Safety Administration (NHTSA) looked into the safety of lithium batteries after a Chevrolet Volt caught fire back in May. After conducting three different tests two weeks ago, the NHTSA found that the Volt's battery either caught fire or began to smoke in two out of the three.

General Motors Co.'s Chevrolet Volt underwent several tests in a NHTSA Wisconsin facility earlier this year. On May 12, 2011, it experienced the side-impact crash test. Three weeks later, the plug-in electric vehicle (EV) caught fire while parked in the NHTSA testing center.

The fire, which was fierce enough to burn other vehicles parked nearby, prompted an investigation of the Chevrolet Volt and the safety of lithium batteries.

The NHTSA conducted side-impact crash tests for the Chevrolet Volt on November 16, 17 and 18. After each test, the batteries of the three separate Volts were then rotated 180 degrees. Out of the three tests, two resulted in fire, smoke or sparks while one remained normal.

The November 16 test had normal results, while the November 17 test led to a battery fire one week later and the November 18 test caused the battery to smoke and emit sparks. The battery packs of the three Volts were not drained after any of the crashes.

The results have led to a formal investigation of the safety of the Chevrolet Volt and its lithium battery.

"While it is too soon to tell whether the investigation will lead to a recall of any vehicles or parts, if NHTSA identifies an unreasonable risk to safety, the agency will take immediate action to notify consumers and ensure that GM communicates with current vehicle owners," said NHTSA.

GM has said that it launched a system where first responders immediately depower the battery of a Chevrolet Volt after a severe crash. This is safety protocol because lithium batteries can catch fire if the internal cells or the battery case are pierced by steel or another ferrous metal. Even the slightest piercing of the battery can lead to a reaction days or weeks later.

"The Volt is safe and does not present undue risk as part of normal operation or immediately after a severe crash," said GM after the NHTSA's tests this month. "GM and the agency's focus and research continue to be on battery performance, handling, storage and disposal after a crash or other significant event, like a fire, to better serve first- and secondary-responders."

NHTSA and GM have both said that they are unaware of any battery-related fires caused by roadway crashes involving customers. However, NHTSA advised EV owners to remain cautious in the event of a crash as they would in a gasoline or diesel-fueled vehicle. The NHTSA's advice includes stepping out of the car and moving away from it while contacting authorities. When responders arrive, they are to check for markings that it is an EV and use large amounts of water on the vehicle if there are any signs of a fire. They are to then contact experts at the vehicle's manufacturer on how to discharge a propulsion battery.

There are currently 6,000 Volt owners on the roads, but the number of EVs cruising around in the U.S. is expected to increase because U.S. President Barack Obama is looking to put 1 million EVs on the roads by 2015.

Sources: The National Highway Traffic Safety Administration, General Motors



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RE: Der
By FITCamaro on 11/28/2011 2:19:45 PM , Rating: 3
Leaking gas doesn't catch fire. Leaking gas on a hot exhaust or engine catches fire. So they'd have to crash running vehicles.


RE: Der
By Samus on 11/28/2011 2:36:17 PM , Rating: 2
Yes, but this problem didn't occur during or after the crash. It caught fire after sitting in a warehouse 2-weeks post crash. The battery pack should have been disconnected and removed by then, which has been common practice on vehicles involved in serious accidents for decades.

Most vehicles, including the Volt, have an innertia switch for the fuel that removed fuel pressure and disabled the fuel pump post-crash, requiring a manual reset.

Perhaps the same technology is neccessary for the battery pack, including onboard diagnostics of Li-Ion/Li-Po cells. In R/C cars we have Li-Po balancers and chargers that can balanced, diagnose and disabled individual cells in a battery. Why doesn't a $40,000 car have the same technology as my $500 R/C car?


RE: Der
By djc208 on 11/28/2011 3:34:20 PM , Rating: 2
quote:
In R/C cars we have Li-Po balancers and chargers that can balanced, diagnose and disabled individual cells in a battery. Why doesn't a $40,000 car have the same technology as my $500 R/C car?


It does, however the issue here isn't about control of the battery pack, it's about damage. If the cell is physically damaged and comes into contact with ferous metals it can start a chemical reaction resulting in fire according to the article.

Plus at it's most basic it's still just a battery. The electronics and chargers may be able to control that battery but if something shorts across the terminals, or they are put into a state outside of their normal operating condiditon, an individual cell may fail which could cause a cascade given time.


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