What happens to A123 batteries when they die?

[drewjet]

This is for my T-Rex 600 RC Helicopter. I drain them at an average 12C with peaks of about 45 amps. I also run it in a few planes with similar loads. I picked up 40 cells from Doc Bass and plan to use them in a bike, soon.

 

[solarbbq2003]

thats a bit worrying that iron phosphate lithiums can also catch fire, first I've heard of it, i've had a couple of packs short but no fire, quite hot, cells expanded, but no flames.
With cobalts ( edan brand older ones cyclone was using) one cell dying in a string of parallel, will bring voltage of other cells down to same voltage (near zero usually). Seems they dont recover well, but cells have been sitting around for a long time in discharged state before i started fiddling with them.
Also using on bikes have noticed a bad cell will get warm during charge/discharge, will keep going for a month or so before dying, so get plenty of warning a cell is on the way out just by its temp, but they are cobalts not iron phosphate.

 

[steveo]

I'm doing single cell testing here

Once of the 5p packs i had made for my bike had gone bad, Still held charge and everything, by the resistance was showing 15-18mohms for the cells that were paralleled after i took them all apart, i noticed the ends had bulged a bit, these i set aside as per i knew they where bad, i went out for dinner with the g/f, my mom called me to tell me she heard a loud bang, when i got home this is what i found.

I think this pack my have overcharged when in series with the remainder of my 66v pack at the time .. strange though .. everything else seems ok for the other cells!


-steve

 

[Doctorbass]

I want to see the video of that one!

I have no idea how toxic the stuff inside is. There should be a MSDS for A123 cells somewhere that spells it out. Maybe you don't really want to know....

Other than the mishap with the pliers, were you sucessful in soldering the cells? I have a bunch that need connecting and I'm still debating whether to wait until I find someone with a big spot welder or attempt soldering them.

MSDS for A123
http://www.gyllingteknik.se/a123/SF000003_04 MSDS Cell.pdf

 

[Doctorbass]

I'm doing single cell testing here

Once of the 5p packs i had made for my bike had gone bad, Still held charge and everything, by the resistance was showing 15-18mohms for the cells that were paralleled after i took them all apart, i noticed the ends had bulged a bit, these i set aside as per i knew they where bad, i went out for dinner with the g/f, my mom called me to tell me she heard a loud bang, when i got home this is what i found.

I think this pack my have overcharged when in series with the remainder of my 66v pack at the time .. strange though .. everything else seems ok for the other cells!


-steve

Steveo, You did a great job with cell measurement!

pay attention to this: the milliohm of the A123 are normally 10-12 miliohm.. not 15 to 18...or rare case

the wires between the charger/analyzer and the cell + contact resistance of the banana plug and the wire on the cell tab ADD milliohm to the reading.. I corrected that with my 4 wire sensing and the real valur are more like 11-12.. sometime 13 or 10.. so the wire add like 5 miliohm total...

Doc

 

[Mathurin]

I still wanna see one of these things get zapped tho.

 

[jeffkay]

Thanks for that MSDS!! Now I can sleep at night. My son has Leukimia (expected to be cured) and now I can show my wife the contents are not known to cause cancer in California.

 

[Doctorbass]

Thanks for that MSDS!! Now I can sleep at night. My son has Leukimia (expected to be cured) and now I can show my wife the contents are not known to cause cancer in California.

Enjoy your life!!!