New York City wants lithium-ion e-bike batteries to be stopped at the border when they don’t meet national safety standards after rash of deadly fires::After a series of deadly fires.
Sub-standard “spicy pillows” need to be banned. The amount of energy and that fact that water or any normal ABC extinguisher cant put the fire out is enough for me to get really strict on regulating them. Especially in apartment/condos
What in the world is a “spicy pillow”?
a puffed-up lithium cell that’s about to explode. soft, squishy, and very flammable!
Bike shop worker here: not only are the direct to consumer Asian eBikes shoddily built pieces of shit with proprietary parts galore, but we refuse to intake non mainstream brands’ eBikes for this reason. Worst shit
Yeah I have the feeling a lot of them are as bad or in some cases worse than bicycles upfitted with gas engines.
We really need a better battery technology, one that doesn’t trivially become an incendiary device.
There has actually been a ton of progress with this over the last decade.
However, everything we have discovered so far either can’t hold as much energy, has really limited charge cycles, or is far too expensive to use at scale.
Ton of progress?
I would refer to that as “research ongoing but no progress yet”.
Current 18650/21700 Li-ion cells are a lot safer than they were 10+ years ago, less chance of thermal runaway and fires now.
trivially it is only when not built or used properly.
We also have gas heating, electricity, cooking with boiling water etc. that all “trivially” become sources of severe injury and death and we manage. Because stuff is built and used according to standards most of the time.
Home gas & electric installations are a lot safer today than they once were. They’re actually a great example of how a dangerous power source can be made a lot safer through better choices and engineering.
The first gas ovens and heaters used coal gas, which is carbon monoxide and hydrogen. The monoxide meant that coal gas was highly poisonous to breathe; and both monoxide and hydrogen are odorless — so you might not know the oven was left on unlit and killing your family.
Modern natural gas is mostly methane, with an unpleasant scent added so we can detect leaks. Methane is unbreathable, but still a lot safer to have in your house than monoxide!
(To be clear, the monoxide was not a contaminant; it’s a fuel. Coal gas burns into carbon dioxide and water, just like methane.)
So here, we got a better gas technology: in fact, we got a whole different gas; a fundamentally safer-for-humans one — and on top of that, added an extra safety mechanism in the form of an odorizer, making the gas stinky instead of odorless.
Same goes for electricity. Modern home electrical outlets are grounded, greatly reducing the chance of a dangerous shock due to a wiring problem or a defective appliance. And modern circuit breakers are much more reliable than the fuses they replaced; and they don’t break, so the homeowner doesn’t have an incentive to defeat the safety device the way folks often did with fuses.
And modern kitchen & bathroom outlets have GFCIs, so an appliance shorting out through water (or your body) will break the circuit.
So here, we’ve gotten better electrical technology too: grounded outlets, circuit breakers, and GFCIs all make electricity much safer than when it was first installed in homes.
To put it morbidly: Coal-gas ovens and ungrounded electrical appliances were both once common means of suicide. Their modern replacements are safe enough that they don’t work for that anymore. Same goes for cars, by the way. Modern gasoline cars don’t put out enough monoxide to kill a person rapidly by inhaling the exhaust.
So yeah, I think it’s perfectly reasonable to say we need a better battery technology, ideally one that doesn’t do this sort of thing.
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Modern electric wiring is grounded and has a proper safety switch if and only if the installation is done correctly. In the same wake your gas pipes in the house are safe if and only if installed correctly and burning appliances like a water heater are only safe if and only if regularly inspected and maintained.
The same is true for Lithium Ion batterys. The technology is not inherently unsafe, in the same way that house installations arent inherently safe. It is merely that the shitty ones and their chargers are not produced following the existing standards on how they need to be designed and maintained and for house installations there is inspectors and other means to enforce standards.
The city forbidding the import of these is the same as them having inspectors to make sure buildings are built according to code.
Indeed we certainly need a better technology, or to enforce better regulations, but currently those batteries are the only alternative to gas. So we try and learn from our mistakes, as usual…
Reminds me of what the hoverboard craze of the mid-10s resulted in, products with a bunch of shoddily-assembled components that turn the batteries into bombs making it onto store shelves faster than the new thing powered by said batteries can get new safety guidelines released for it
Imagine reading this in the 80s - we would have thought that Back to the Future was prophetic.
As someone who designs global battery powered products in the USA and is well versed in the regulatory hurdles, enforcing these rules is long overdue. The fact that people willingly buy and bring these illegitimate products into their home and wear them on their body is mind blowing to me. You can design a safe lithium products but doing it requires full knowledge of the chemistry, electrical design, safety certification process and some wisdom. Chinese vendors on Amazon have very little of this.
If Amazon are going to peddle this crap and profit from it, they should be held accountable for it as well.
The amount of absolute shit on there is absurd.
Remember those popular side-wheel scooters from China that burned down so many houses here in the USA? People stopped buying them because everyone became aware of what a fire hazard they are. You don’t see them at all anymore.
China and a few other countries with cheap labor markets are really bad about consumer product safety. They just don’t have any law enforcing safety standards. They use maximally cheap production resulting in unsafe products and there’s no local legal framework to disallow it. People buy products from these markets without being aware of the hazards. They assume domestic safety standards and that’s simply not the case.
New York city and state law can be intrusive and I consider them and California examples of what I call “nanny” states, but that’s one I agree with. Upholding safety standards is one of the few situations where I favor regulation of imported products.
For what its worth, cheap labor markets and China especially are perfectly capable of building safe products. Most high end brands make their stuff in China. And Chinese engineers are very capable of making safe products. The issue is there isn’t motivation other than a foreign country with foreign engineers probing them and pushing them to make a product the right way. Otherwise they can drop ship it cheaply with no brand, no warranty, no risk and the only exchange that matters is the sale and then they’re free of all obligation. Companies with a brand need to stand behind it and are at legal risk so the stakes are completely different.
I do this on the side, buy bulk low cycle lithium ion cells, spot weld them together into banks, and make larger packs.
What is the biggest safety problem seen with these?
My packs are 64P, right now 4s but hopefully 7s soon.
My main safety features are per-cell 5A fuses, 100A fuse on each bank under the battery wrap (not removable without cutting the wrap), and keeping the cells and nickel strips under a layer of kapton tape, followed by an ABS plate I designed and printed, then all the wiring, taped to the ABS with kapton tape. Which is then inside of the battery wrap. I use a lower current circuit breaker on the whole circuit.
My layman research suggests that loose wires are the main reason for fires, so all wires are taped down, and the nickel strips are protected from stress. A cell shorting out should blow the 5A fuse. And if I’m careless and bump the two terminals to a conductor while moving it, there’s always a 100A limit. I also only use low-cycled matched cells and currently am charging to 4V and discharging to 3V.
Any other things I can do to make it safer?
Whoa, there is a LOT to unpack here so I will do my best. Please understand as I’m an engineer by training I will always advocate towards caution rather than YOLO so I’m going to spell out a lot of doom and gloom so read at your own peril. I’m not trying to poop on your hobby/business.
Inquiries; What kind of cells, 18650s? What brand cells do you buy and do you know their use history? Do you mix model numbers? I assume these are bare cells with no protection circuitry and you add the 5A fuse? What kind of fuse, a PPTC? And is that a typo, 64 in PARALLEL? 4S64P? That is bonkers, what the heck are you doing with them that requires that kind of amperage?
OK OK, so, do you use a BMS? How are you handling these packs other than the fuse? You NEED a BMS to at least balance the 4 series strings and monitor the packs temperature and shut it down if any part of the pack gets too hot. Lithium cells have a very narrow range where charging is allowed and a slightly wider range where discharge is allowed but at some point you need to turn it off. In terms of massively paralleling the batteries this is dangerous territory unless you are acutely aware of the cells, their limits, age and tight monitoring to notice when a handful of the cells are aging (getting higher ESR and forcing the others to handle the increased current which might exceed their safety limits). The end goal is to balance the current evenly between the cells in parallel and its not trivial, if you force all the current through a handful of cells you will ignite a lithium fire.
Regarding charging to 4V and discharging to 3V, most modern 18650 cells from good vendors charge up to 4.2V with a float charge so you’re leaving charge behind but 3V seems way too low. I guess it depends on how long you want the pack to last. There is max and min voltages the cell vendor will recommend but then if you ask they can give you plots of the cycle life at different depths of discharge and typically in my world we don’t go much lower than 3.2V to ensure the packs last well past 500 cycles. The deeper you discharge the more stress you put on the cathode.
Finally, loose wires are certainly a cause for fires and since you’re hand making these its likely your biggest risk but in addition to that dendrite growth in the cells. If you abuse the battery either with temperature, over current/current imbalance you slowly introduce dendrites which keeps increasing the chance the cell will catastrophically fail with continued cycling. Its statistics and with the number of batteries you’re playing with any little bit of abuse will grossly magnify the chance of a big failure to happen. Cells can and do spontaneously fail from internal damage but its a lot more likely to happen during charging.
In summary, you are playing with some serious power levels here, I would read up some more before you get much further. Especially before you step up to 26V! I hope this helps!
Cell quality is important. You want to be using known good quality cells like those from Panasonic, Samsung, LG, etc…
How you manage temperature, charge and discharge is also really important, dendrite growth can cause cell failure in time. Charge temperature is extremely important. So you want to make sure you’re using a smart programmable BMS where you can set up all the protections properly. Ideally one with as many temperature probes as you can find, 4 is good, 8 is better and some will have that many.
Otherwise making sure nothing can short out internally is important too, but it sounds like you’re putting some thought into that. Most critical IMO from what I’ve seen on pre-made battery packs is making sure your series banks are well insulated from each other and have no chance of vibration causing the cells to wear through their heatshrink and touch each other.
Is this an American thing? In Europe we have regulated batteries and chargers made by well known companies like LG, Samsung and Panasonic.
People in Europe can easily buy cheap shit from wish.com and whatever that new one is and import them, also you’ll get them on ebay from people that just importing in bulk. They will certainly have a nice FCC and CE sticker on them. But, no they’re most certainly not certified!
Cheaply made non conforming electronics has been a thing for decades now. But until now it’s generally been power supplies that pollute the radio waves with noise (and might go pop one day, but probably not cause a fire). Now we’re messing with lithium based batteries without the proper safety circuits you see on property certified stuff. They can cause serious self fueling fires that are hard to put out.
In short, in Europe I would only trust something I bought on a retailer with a national presence and definitely NOT ebay.
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