A123 LiFePO4 BAE System Module Teardown

[CrimpDaddy]

New member here, but not new to batteries... I really wanted to get some LiFePO4 cells and this is what I started with. This thing was a bit of a pain... but I got it done.

https://youtu.be/V4JTQ43alDo

[youtube]V4JTQ43alDo[/youtube]

Part 2 video posted... see the results here.
https://youtu.be/PER-dGjM-m4

[youtube]PER-dGjM-m4[/youtube]

 

[MJSfoto1956]

Great video. Thanks for posting. Looking forward to part 2.

 

[fechter]

That is somewhat similar to the Hymotion pack made for a plug-in Prius. Those cells are pretty robust but don't like getting over discharged. The sub modules would be a nice size for an ebike. You should inspect the welds, as this was the main failure point on the Hymotion units.

I like the subliminal advertisement for a ham radio at the end of the video.

 

[CrimpDaddy]

That is somewhat similar to the Hymotion pack made for a plug-in Prius. Those cells are pretty robust but don't like getting over discharged. The sub modules would be a nice size for an ebike. You should inspect the welds, as this was the main failure point on the Hymotion units.

I like the subliminal advertisement for a ham radio at the end of the video.

Didn’t know about the Hymotion pack, but now I do. Thanks.

The welds look to be in really good shape. I saw other people trying to remove the spot welds only to end up damaging the battery because it was so robust. I opted to keep them in place as use as is. I might even tear down a module further into a 2p1s mini 12v pack, but the capacity isn’t all that amazing. Almost feel like I would be better off just getting a small 5Ah SLA like those used in an APC unit.

The only reason I even bough these LiFePO4 cells was for 12v compatibility… I am actually well stocked on Li-ion chemistry for 24v, 36v, 48v configurations, but I really wanted to run some items without needing a DC-DC for 12v.

Glad you liked the ham radio stuff, trying to generate more interest, I have a lot of hobbies and they all seem to tie into to the battery stuff eventually.

 

[john61ct]

Most of these currently being sold are in very poor shape, that's why they were pulled from the buses.

If you get them still wired for under a buck each, and 20% are still OK, maybe worth the trouble.

Beware loose ones being sold off, likely the discards from that process.

In the past there have been some claiming to be NOS from when assets were distributed from the original A123 company getting shut down.

If claimed new, be ready to do stringent load / capacity testing soon as they arrive so if NG can send them back, with eBay seller has to refund 100% and pay return shipping, even if they try to state No Returns

 

[Addy]

Most of these currently being sold are in very poor shape, that's why they were pulled from the buses.

That was the case for me. I bought 2 of these packs and got a pretty good deal on them. I've disassembled one of the packs and made a truck starter battery with it. I tested the cells, they have ~65% capacity left.

The capacity is disappointing, but with a 4s16p pack made from these cells, my V8 truck starts up just fine.

 

[CrimpDaddy]

I agree with the above… but I bought these modules over a year ago and finally got time to tear into them.

I still have the make the Part 2 video, but I have already tested one of the batteries and there is approximately 35% capacity loss from the spec sheet. They are showing obvious signs of degradation.

Test was done at 10 amp discharge rate from 3.6v to 2.5v
One of the cell groups had a higher internal resistance than the rest, and that is the group that hit 2.5v while the others were still at about 2.7-2.8v

Certainly nice to have some LiFePO4 cells, but I think I could have got a lot more value just buying something else. These are not something I bought buy again if I had the chance to do it over.

That said, for my use, intermittent high loads where capacity is less of an issue, like radio communications and portable air compressor, should work fine.

 

[john61ct]

Yes, 80% is the usual industry definition of EoL, but they'll still have some cycles left before only good for scrap.

The initial acquisition cost per kWh is one thing, cost per year over useful lifespan a very different matter.

Monitoring for balance and safety much more critical as the EoL point is passed.

For some use cases paying 5x more for new cells works out lots cheaper overall.

 

[CrimpDaddy]

They weren’t even that cheap to begin with… $141 per module of 96 cells which includes shipping.

730 watt hours new
475 watt hours @ 35% degradation

$297 per kWh for EOL cells

Needless to say, not my best purchase…

 

[CrimpDaddy]

Part 2 completed... pretty much confirms what was written here. I would probably avoid these modules unless you can confirm they were in good condition before purchase.

Was really hoping for an A123 score, but this wasn't it. Can't win them all.

https://youtu.be/PER-dGjM-m4

 

[john61ct]

They weren’t even that cheap to begin with… $141 per module of 96 cells which includes shipping.

I think $6-8 per cell is the new price, so say a third are worth using (90%+) would be an OK-to-reasonable result.

The wrecking yard in Quebec with thousands of packs not yet broken down may increase the odds.

I would not buy from someone who is obviously testing, likely keeping the good ones themselves.

 

[CrimpDaddy]

My research indicates the same on the cost of new cells… about $6 to $8 each

$141 per modules was a used price making each cell $1.47 each, but they appears to have a high cycle life an average of 37% capacity loss. These cells were not previously tested, at least they don't appear to be.

The plan was never to break it down into individual cells, but at this point, for the “12 volt chunks” which have highly degraded cells, like the last one I tested, will end up getting broken down further.

At the end of the day, for the labor involved, and for the general condition of the cells, I would actively avoided these modules. It’s a shame because I was really hoping for some decent quality A123 cells, and to leave it in the configuration I had in the video.

 

[john61ct]

There are NOS ones come up sometime.

$99 from the wrecker is always available, if the sample turned out OK he'd probably take $500 for a whole bus' worth if you showed up with a truck.

16packs x96 cells each.

 

[CrimpDaddy]

ALWAYS... show up with a truck... Ill be making more detailed video on these sooner or later too.

So far so good, the couple that I spot checked are pretty much full capacity and low internal resistance!
60.4Ah x 18.5v = 1.11 kWh

 

[john61ct]

score!