VERY INTERESTING. Firefighter friend of mine would love to see this.

Interesting... wrong assembly caused the fire. Human error.

I'm stunned that the conversion system didn't employ multiple temperature monitoring points along with a warning system should any part of the battery exceed a safe temperature. These are Li-Ion batteries for christ sake! They need to have auxillary cooling and monitoring systems to ensure safety. Tesla has gone through great expense engineering these safety systems. Obvioulsy the company that made this batter didn't. Very sloppy.

I have seen terminal stud damage like that on fork lift motors with poor connections. You also get the same results.

Very interesting report, thanks for posting!

Rob

From the investigation, there were a number of obvious problems in the Hybrids Plus conversion battery design:
1.) clamshell plastic in compression without appropriate load distributing washer (incorrect mechanical assembly)
2.) parallel batteries built with full sheet nickel buss bar instead of individual fuseable links.
3.) known flammable foam used in the pack construction.
4.) lack of a safety mechanism to prevent conductive ejected battery material from breaching the electrical isolation between the battery pack and the vehicle chassis.
5.) marginal thermal sensing design.

This underscores the amount of Engineering and upfront failure analysis that has to go into proper battery pack design. The DIY projects may or may not incorporate the appropriate safeguards.

It's important to remember that Hybrids Plus and Hymotion are two very different companies. Both companies use the A123 LiIon cells in their pack design, but Hymotion is a wholly owned subsidiary of A123 systems while Hybrids Plus is not.
I have a feeling that Hymotion would not violate their parent companies own design guidlines with regard to pack design. However, the internal construction of their conversion unit seems to be a closely guarded secret at this point. Aside from the high up-front cost at this time, I think I'm going to wait until I can see a complete teardown or at least get a look at the electrical construction inside the Hymotion unit.

maybe because 123 is a company from GM ( if i am not mistaking or is it chevron )
this fire did the electric car deal no good..

Yes, and they shot Kennedy too.

Seriously, not everything is a grand conspiracy. I'll grant you that if I were the Ford dealership that the car was towed to originally, I'd probably be taking lots of pictures to show my customers what happens when you buy those spooky foreign cars, now let me show you a Taurus.....

However, the report seems to clearly point to a sloppy mechanic doing the final assembly that was the 'straw that broke the camel's back' to a design that had a few problems in it that are perfectly clear in hindsight but probably weren't during original design. The good thing is that it looks like they did a good job of trying to learn from their mistakes and show that they had done so with this report. Also, the report was a really good insight into the conversion that I found interesting to read. Thanks to the OP for sharing it.

Conversion vs OEM really isn't the main deal. Lest we forget, this happens to the most technical groups as it does to shade tree mechanics/electricians. NASA's 'Challenger' Shuttle blew up because a known O ring problem finally failed under the very conditions they knew it would failed. They failed to re-design. They failed to order new parts. They robbed used parts from Peter to pay Paul. They ignored engineers when they waved red flags about the known issues. Lack of integrity ... arrogance ... sloppy ... lazy work ethics. So legislators will have to make laws to prevent it. Sadly, most laws are written in the blood of others.

Well, I hope Hymotion is looking at this carefully and doing any redesign indicated.

I saw two Hymotion A123s installed on two fleet cars for SDGE. Hymotion requires that one of their trained installers do it. These guys were flown down from San Francisco to do it.

I wonder if the insurance refused to compensate the owner of the car?

Actually, there's no reason you couldn't put in temperature sensors.

What disturbs me is that Hymotion is supposed to have authorized installers.

I would think they'd be taking more care in being sure all connections are tight and locked. And I'm confused. Were the washers/spacers actually placed under the bolt head, rather than under the nut?


Dave M.

This is not a Hymotion conversion.

Rob

Any chance the owner would dare try to have the toyota warranty enforced?

I expect it will be a finger-pointing blame game between Hybrids Plus and the installer with the poor Prius owner caught in the middle.

Whether insurance company will pay anything will depend on the exact policy the owner has.

I expect with the information available in this post, the owner will be looking to sue both installer and Hybrids Plus. I hope there's no fine print in anything he signed absolving them of anything that happens no matter what.

A123 is a company owned by an MIT professor, which has invented a new Li ion cell based on lithium iron phosphate. I don't think GM owns them. Their batteries are being used by a lot of companies, including Black & Decker. Toyota is looking at them for the next generation Prius.

The fire here appears to be unrelated to the battery technology--due rather to faulty assembly.