Friends, I’ve gotten myself into a pickle and I need some help.
A few years back, I decided to get into solar power by building a complete PV system inside a mobile trailer. The rationale for this doesn’t matter for the current discussion, but for the curious, I wrote an article outlining the whole design and build process. Briefly, though, the system has two adjustable PV arrays mounted on the roof and side of a small cargo trailer, with an integrated solar inverter-charger and a 10-kWh LiFePO4 battery bank on the inside, along with all the usual switching and circuit protection stuff.
It’s pretty cool, if I do say so myself, and literally every word I’ve written for Hackaday since sometime in 2023 has been on a computer powered by that trailer. I must have built it pretty well, because it’s been largely hands-off since then, requiring very little maintenance. And therein lies the root of my current conundrum.
Spicy Pillows
I generally only go in the trailer once a month or so, just to check things over and make sure no critters — or squatters — have taken up residence. Apparently, my inspections had become somewhat cursory, because somehow I had managed to overlook a major problem brewing:
This is one of two homebrew server rack battery modules I used in the trailer’s first battery bank. The LG-branded modules were removed from service and sold second-hand by Battery Hookup; I stripped the proprietary management cards out of the packs and installed a 100-amp BMS, plus the comically oversized junction box for wiring. They worked pretty well for a couple of months, but I eventually got enough money together to buy a pair of larger, new-manufacture server-rack modules from Ruixu, and I disconnected the DIY batteries and put them aside in the trailer.
Glass Houses
As for what happened to these batteries (while not as dramatic, the case on the other one is obviously swelling, too), I’m not sure. There was no chance for physical damage inside the trailer, and neither battery was dropped or penetrated. Whatever happened must have been caused by normal aging of the 28 pouch cells within, or possibly the thermal swings inside the trailer.
Either way, some of the pouches have obviously transformed into “spicy pillows” thanks to the chemical decomposition of their electrodes and electrolytes, creating CO2 and CO gas under enough pressure to deform the 14-gauge steel case of the modules. It’s a pretty impressive display of power when you think about it, and downright terrifying.
I know that posting this is likely going to open me up to considerable criticism in the comments, much of it deserved. I was clearly negligent here, at least in how I chose to store these batteries once I removed them from service. You can also ding me for trying to save a few bucks by buying second-hand batteries and modifying them myself, but let those of you who have never shaken hands with danger cast the first stone.
To my credit, I did mention in my original write-up that, “While these batteries work fine for what they are, I have to admit that their homebrew nature gnawed at me. The idea that a simple wiring mistake could result in a fire that would destroy years of hard work was hard to handle.” But really, the risk posed by these batteries, not just to the years of work I put into the trailer, but also the fire danger to my garage and my neighbor’s boat, camper, and truck, all of which are close to the trailer, makes me a little queasy when I think about it.
Your Turn
That’s all well and good, but the question remains: what do I do with these batteries now? To address the immediate safety concerns, I placed them at my local “Pole of Inaccessibility,” the point in my backyard that’s farthest from anything that might burn. This is a temporary move until I can figure out a way to recycle them. While my city does have battery recycling, I’m pretty sure they’d balk at accepting 90-pound server batteries even if they were brand new. With obvious deformities, they’ll probably at least tell me to get lost; at worst, they’d call the hazmat unit on me. The Environmental Protection Agency has a program for battery recycling, but that’s geared to consumers disposing of a few alkaline cells or maybe the dead pack from a Ryobi drill. Good luck getting them to accept these monsters.
How would you handle this? Bear in mind that I won’t entertain illegal options such as an unfortunate boating accident or “dig deep and shut up,” at least not publicly. But if you have any other ideas, we’d love to hear them. More generally, what’s your retirement plan for lithium batteries look like? With the increased availability of used batteries from wrecked EVs or even e-bike and scooter batteries, it’s a question that many of us will face eventually. If you’ve already run up against this problem, we’d love to hear how you handled it. Sound off in the comments below.
The ‘POS’ sticker on that battery does seem accurate, at least! ;)
As for what you should do… I think you said it in the last paragraph. At the very least, I don’t think you’d lose anything by seeing if they’d accept the batteries for recycling, other than a little time – the absolute worst they can do is to say ‘no’.
Yes, a phone call is free…
Not sure where you live, but you might want to check with your municipality. Mine has an event a couple of times a year where they will take all manner of hazardous waste off your hands, and I think that does include batteries.
Slavia 634 pellet gun. Then Fiskars e-tool to bury them.
I’d call them and tell them you’re a consumer, have a bunch of batteries that are EOL and if you can bring them. Here in the EU, to prevent worse(i.e. you dumping them off the side of the road), the recycling places have to accept whatever you bring. It’s different when you’re a company. Then they will have a rate XXX per kg that you have to pay for them to accept the stuff.
That wasn’t the case for my local ‘recycling centre’ here in the UK at least, which should still be by the rules much the same if not stricter than the EU. They might technically be obliged to, but wouldn’t actually do so in practice…
Still it is the right move to try and get them into the battery recycling waste stream before doing anything else.
My local transfer station has a battery recycle program, I’ve taken a lot of LiIon cells there and while they gave me their best grumpy faces they’ve always taken them
I actually think they were grumpy because instead of hanging out inside the shed doing naff all they actually had to work to pack them up for transit.
I always kill the cells with a giant resistor before I take them in.
Y’know, I have the same kind of question about lots of things that are supposed to be properly disposed of, and which I’d like to handle appropriately if that is an option:
Fluorescent bulbs usually contain mercury, and are supposed to be “properly disposed of” — Around here (semi-large city!) there’s like one store 30 minutes away that will take T8 / T12 tubes for a couple bucks each, and then hopefully do something with them other than pocket the money and toss them in the dumpster out back.
I recently learned that PCBs (the polychlorinated kind, not the printed circuit kind) aren’t just a concern with utility-scale transformers — there’s also PCB containing capacitors and fluorescent ballasts. But, the official guidance on PCB containing materials is really only applicable to large companies (things like “contain them in a dedicated 50-gallon drum for disposal with your contracted PCB disposal firm”); what’s a hobbyist with a few old capacitors or a homeowner with a few old fluorescent fixtures supposed to do?
E-waste in general, of the electronics hobbyist sort rather than the occasional complete computer sort — Municipal “computer round up” day around here is for computers as unit, not for a box of old circuit boards.
And that’s not even getting into things that may be radioactive, etc!
The core issue seems to be that there’s no or very little full-lifecycle management for things that are potentially hazardous at end of life. The original manufacturers are not forced to consider EOL, so they limit their liability by slapping a sticker that says “dispose of properly” and wash their hands of the matter, even if “properly” is not an option that exists.
do what the bomb squad would do, detonate them in a controlled manor. at least that’s how i deal with swollen cells.
i have a lot of 18650 cells i need to get rid of. they are a very old at this point, none too useful, but most still carry a charge. im not sure if i should just hook them up to a resistor to discharge them down to zero over a long period of time such that they can be thrown away without sparking. our town does not have battery recycling at all. my first concern is getting them out of the house so they dont start a fire.
UK here, at least in my borough, I can dispose of pretty much any battery at my local recycling centre and they’ve never turned down (or even checked) moderate sized Li-Ion cells.
Not sure if they’d balk at those beasts but I’m also fairly sure they’d not even ask so it would be OK.
Maybe if I was in a different country I’d see if there’s a recycling program for EV cells?
If i’m understanding the narrative, they puffed up because you stopped using them. Once they deep discharge and sit on a shelf for a year, they all seem to puff up in my experience.
They’re relatively benign if they’re discharged, so that’s my first step. Make sure they’re fully discharged. I like to leave an LED on my old packs to drain them, but if there’s any juice at all left in your pack you’ll probably want more current than that :) Not sure if your architecture means you’re gonna have to test / discharge each cell separately or if you can do the whole pack at once.
Once they’re discharged, do whatever. I really don’t know how the municipal dump handles these things because if you bring the fully charged but puffed batteries, it’s a real time bomb. But if they’re discharged, no reason not to take the whole pile.
Anyways i would have thought the point of putting it in an outbuilding is that you are accepting the fact it’ll burn down someday :)
It seems some of your conundrum as described rests on your assumption of who will or won’t take them rather than having actually called and asked. If so, that might be a good first step.
I don’t know where you’re at. I use calltorecycle.org who sends me this 5 gallon steel container full of vermiculite and I put industrial lithium batteries in it and ship it back. It’s a paid service, of course, but at least then they’re gone. CellblockEX I think is the ones I use. They have a separate process for smaller things like laptop batteries.
Easy, just throw it in your carry-on for your next flight. TSA will confiscate it, and it becomes their problem.
Oh goodie, the nuclear industry finds a solution.
chemically extract the lithium for reuse. I would assume this is the path that battery manufacturers want end users to do (unless they don’t care about the environment), or do they offer any alternatives?
Dude, what are you doing with that much power? I’ve got one 84AH battery in mine, and it’s plenty for lights, phone charging, fan and occasional electric blanket to pre warm the bed, and never used more than 40%. How much do they weigh in ritual?
In the US (at least in my area) the local Batteries+(Bulbs) franchise will take them will take them free of charge for disposal. I’ve taken both big SGM and Li-Ion packs to them and they don’t even blink.
And they told me I was a grumpy old fellow for fearing embedded lithium batteries sitting past their date in all sorts of modern consumer devices.
My current lithium ion disposal plan is to put them in a box for my children to inherit. Hopefully they will have easier access to battery recycling.
Seriously though the local recycling centre is a good bet or Tesco have a battery-shaped barrel where they accept batteries with no human interaction… Unless it starts smoking I guess.