NHTSA and lithium ion batteries

[stopcrazypp]

Oh yeah, I've already been arguing with someone on Peak Oil who kept trying to say the Volt was totaled and caught fire from a 20 mph "fender bender". A few videos settled that argument.

It seems like that guy is quite dense and likes to post completely misleading/irrelevant images. He keeps describing the test like it is a low collision that many people will experience, even after you showed the videos.

The original test back in May was a 20mph side pole test, which definitely would total any car; you can link my Volt side pole videos for reference. The six month delay in public announcement was to verify what caused the fire.

Press Release direct from GM:

The initiatives follow six months of research and testing in the United States with the National Highway Traffic Safety Administration designed to induce electric vehicle battery failure after severe crash situations.
The agency advised GM on Friday that it would open a preliminary evaluation of Volt battery assemblies after NHTSA test results caused electrical fires up to three weeks after an initial vehicle New Car Assessment Program side pole crash test.

http://media.gm.com/content/media/u...l/content/Pages/news/us/en/2011/Nov/1128_volt

Press Release direct from NHTSA makes it clear the conditions of the subsequent three tests in November (they were done directly on the battery in order to ensure duplication of the results, so should NOT be taken as examples of a regular crash test; a fact many media outlets completely missed):

In an effort to recreate the May test, NHTSA conducted three tests last week on the Volt's lithium-ion battery packs that intentionally damaged the battery compartment and ruptured the vehicle's coolant line. Following a test on November 16 that did not result in a fire, a temporary increase in temperature was recorded in a test on November 17. During the test conducted on November 18 using similar protocols, the battery pack was rotated within hours after it was impacted and began to smoke and emit sparks shortly after rotation to 180 degrees. NHTSA's forensic analysis of the November 18 fire incident is continuing this week. Yesterday, the battery pack that was tested on November 17 and that had been continually monitored since the test caught fire at the testing facility. The agency is currently working with DOE, DOD, and GM to assess the cause and implications of yesterday's fire. In each of the battery tests conducted in the past two weeks, the Volt's battery was impacted and rotated to simulate a real-world, side-impact collision into a narrow object such as a tree or a pole followed by a rollover.

http://www.nhtsa.gov/About+NHTSA/Pr...gation+of+Post-Crash+Fire+Risk+in+Chevy+Volts

No point in linking other media reports because they are all summaries of the above press releases and many are not accurate (some because of loss in summery, others because of injected biases/speculation, particularly true of blogs).

 

[Tranhv68]

How about lithium phosphate batteries?

Have a look at this pretty convincing video.

http://www.youtube.com/watch?feature=player_embedded&v=O8R0ig0J4wk

 

[JRP3]

That's what most of us DIY types use, though not the overly expensive Valence brand. The Spark, using A123, will be using LiFePO4 chemistry. The drawback is lower specific energy density than the LiCo and LiMnCo that Tesla uses, though longer cycle life, higher thermal stability, and higher C rates.