Lithium-ion cells deliver very high energy densities compared to many other battery technologies, but they bring with them a danger of fire or explosion if they are misused. We’re mostly aware of the battery conditioning requirements to ensure cells stay in a safe condition, but how much do we know about the construction of the cells as a factor? [Lumafield] is an industrial imaging company, and to demonstrate their expertise, they’ve subjected a large number of 18650 cells from different brands to a CT scan.
The construction of an 18650 sees the various layers of the cell rolled up in a spiral inside the metal tube that makes up the cell body. The construction of this “jellyroll” is key to the quality of the cell. [Lumafield’s] conclusions go into detail over the various inconsistencies in this spiral, which can result in cell failure. It’s important that the edges of the spiral be straight and that there is no electrode overhang. Perhaps unsurprisingly, they find that cheap no-name cells are poorly constructed and more likely to fail, but it’s also interesting to note that these low-quality cells also have fewer layers in their spiral.
We hope that none of you see more of the inside of a cell in real life than you have to, as they’re best left alone, but this report certainly sheds some light as to what’s going on inside a cell. Of course, even the best cells can still be dangerous without protection.
Of all the articles I’ve seen on nearly 20 years on Hackaday, I’m gobsmacked that this has zero comments. This is a fascinating study, and has real-world implications for nearly every tech object that uses 18650s (read: an awful lot!). Cheers for bringing it to our attention [Jenny]!
There’s nothing to comment: everybody either knew it or suspected it already.
What’s interesting is how any industry can make a billion of something and not turn out at least a few duds. Alternatively, battery fires are being under-reported in the news.
I try not to buy anything with a lithium battery in it, because it will become a fire hazard at some point and it’s just built-in obsolescence – but it’s getting harder these days since everything needs to be rechargeable for some reason. A simple desk radio for instance: instead of a standard wall plug, it’s now USB-C with a lithium cell inside. Why?
The other day I was looking at a nice desk lamp – but oh – it’s got a rechargeable lithium battery inside and it’s going to die in 5 years being constantly plugged in to USB-C, and it needs a USB-C charger to function instead of a simple wire with a euro-plug on the end. Again – why?
There’s no functional purpose to put batteries in everything to make them theoretically portable but not really – except the fact that it gives you a reason to replace the product every couple years in fear of it catching fire when the battery goes out.
Small radio with usb-c totally makes sense – its much cheaper, safer and compact than a radio with mains voltage inside.
Somebody probably needs a rechargeable lamp – half of all restaurants in San Diego use small rechargeable table lamps.
When is the last time when a lithium battery in your device catches fire because it’s too old and not because the device is poorly made.
You are on hackaday, I think you have skills to easily replace any single lithium battery.
Sorry, but your post is just an old man rant.
Perhaps, but then again it could just have a wall transformer and a regular barrel jack. Same difference. The argument isn’t really against USB-C though, but against embedding lithium batteries by default.
Never, because I keep throwing them away when they no longer hold charge and/or start to show signs of the “spicy pillow”. I actually emailed one manufacturer to ask them if using their device would be safe once it no longer holds a charge, and they replied back “No, get rid of it.”
Sometimes. Other times just getting into the device without breaking the snap fit tabs and putting dents in the seams seems impossible. There’s one “fake oil lamp” type of lantern I own that I’d really like to keep and replace the battery with a simple wall transformer, but I’ve yet to figure out how to actually get in without ruining the paintwork. It’s just glued shut all over.
“it could just have a wall transformer and a regular barrel jack”. There’s nothing regular about a wall transformer barrel jack. Wall warts with barrel jacks come in different sizes, different voltages with some being AC while some are DC. USB-C on the other hand is an actual standard capable of supplying various voltages. Welcome to the future
Also, this:
https://www.bbc.com/news/science-environment-63809620
People don’t necessarily even know there’s a lithium battery inside some doodad, especially when it’s built-in and non-accessible, and keep chucking them into regular e-waste disposal instead of hazardous waste collection where they belong.
Are you Amish?
I replaced my cordless drill with an eggbeater drill explicitly for the point that the batteries won’t go empty and bad while the drill is sitting on the shelf.
Now when I need to drill a hole, I don’t have to drive out to the hardware store to buy a replacement battery to a cheap drill that’s no longer being manufactured or sold, so I’d have to buy a new drill anyways. I could buy a better drill of course, but the story with the battery would be the same, and the replacement battery would cost as much as the cheap drill.
your name is just the chefs kiss with that comment lol.
anyway there’s at least 3 brands plus the lesser known ones that tend to be specific to store chains (and owned by them) that are quite consistent with their batteries so your argument is invalid imo
Sometimes they are consistent, eventually they’re not. If a store keeps the same cheap drill and spare parts in stock for 10 years, I will be surprised.
To me it really sounds like your just against the recent trend of making most devices rechargeable. It’s understandable but that’s the direction things are going and that trend will continue. Personally, I like the idea of having the convenience of mobility but I do find some items do not really fit the bill and seem like a gimmick. Most people would say I made a bad choice when I purchased a zero turn mower that is battery powered last spring. Defenitly one of the best decisions I’ve ever made as far as my lawn is concerned..people can state otherwise on this comment forum but for me it’s been excellent.
Dude is a LuDudite
i agree that it’s a bummer when something that should be corded has a lithium battery inside. it’s very rare for a lithium battery to last in the always-on-the-charger scenario. but mostly i’m able to find corded versions of these things. i guess because i’m looking at a “desk lamp” and not a “nice desk lamp” :)
but i’m glad it’s happening to battery-powered devices. all the downsides you suggest are real but i’m so tired of alkaline batteries these days. every single AA/AAA-powered device i have is ruined after a battery goes flat in it and leaks lye all over everything. the batteries start leaking before the device stops working! am i suffering from the incredible efficiency of the modern least-cost boost-buck regulator? every device, a joule thief? and to add insult to injury, alkaline batteries are so expensive. and the fake-alkaline lithium batteries are even more expensive, and i’ve learned they’re often defective from the factory.
i’m just tired of throwing away flashlights after a single battery change. lithium ftw
That’s the other problem. Things that used to be powered by disposable batteries are now powered by non-replaceable cells, which actually defeats the point. Say I want a battery powered radio – well, now I got to bring a charger and find a socket, and wait couple hours for it to charge instead of just slotting in new cells.
Fat lot of good that will do when the power is out and you need a radio to listen to emergency broadcasts.
The trick is to keep batteries in the box they came in until you actually need them, instead of forgetting them in the device that you’re not using (or which is normally plugged in to wall power).
Then again, I’ve never had such bad luck with alkalines. I just buy the cheapest shop brand, and never Duracell.
Because most people prefer having to charge a thing once a month (longer?) over a bunch of AC cords and splitters. Also some devices with bodily contact like shavers and oral irrigators are arguably safer when there’s no possible connection to the mains.
What can be done is mandating standardized replaceable batteries including 14500, 10440 and smaller.
The battery in these desk lamps or radios doesn’t even last that long. It runs for 3-6 hours and then you’re done, and it gets worse over time. In practice you just leave it plugged in, because removing the cord would be more trouble.
They’re not portable in the sense that you could bring them along somewhere and expect to operate them without wall power, because you can’t replace the battery when it goes empty. I suppose you could also bring a big power bank, then wait a while for the battery to charge, and then try to figure out how to charge the power bank when it goes empty.
Electric shavers, that I can understand. At least the battery lasts for more than one shave.
Not to mention how inefficient and stupid it is to charge a battery to charge a battery.
A radio that only runs for 6 hours is just bad design; either they underspecced the battery criminally, or the circuitry is a straight up lemon. And all batteries lose capacity over time from wearing, but it’s worse if you charge it deeply (typically to get more run time out of the same battery). Maybe the designer just retrofitted an old desk radio design where efficiency wasn’t a big concern with a battery and charger circuit. With me it’d go straight into the scavenge for parts bin.
Yep. They are badly designed compromises – or rather, running on battery is a “value added” afterthought: they’ve designed the thing to be both a desk radio AND a portable bluetooth speaker as if there weren’t better options for that.
A desk radio or a portable bluetooth speaker typically has a bigger, heavier, and less efficient speaker to give it a better sound quality and more bass than your typical battery powered portable FM radio. It’s not that the design is necessarily “old and inefficient”; simply that it’s a different use case with different design parameters.
If you want a nice big sound and a long battery life as a portable FM radio, you need a much bigger battery. Some bluetooth speaker like a JBL Charge 2 has a 6000 mAh battery and it lasts 12 hours – which is fine for its typical use case. Meanwhile a portable FM radio, let’s say a Panasonic RF-2400D, runs on 4xAA (roughly 2000 mAh), and while it’s not great in terms of sound it gets 60 hours on the batteries – which is the entire point.
A desk radio is neither a portable bluetooth speaker nor a portable FM radio. Its point is to look nice and sound good, and sit on the desk as an element of furniture.
Suppose you do. Then what? You go on a hike, bring your desk lamp along with you, and a set of spare batteries, swap the batteries once and oh… you need to recharge them from the wall. Right, so now you need to bring the charger along too, and find a wall socket.
I suppose these things make sense if you want to move your desk lamp around the house, like carrying a lantern to the toilet at night, or you’re too cheap to buy another lamp for each location.
or… you charge the batteries beforehand
How do you charge the batteries twice before you use them?
You’re on the go, you have a set of spares, so you get one swap and then you have two sets of empties. That’s just kicking the can down the road, while the real problem is that the device is not designed to be truly portable because of contradicting requirements. Being able to swap batteries is not the issue.
and on top of that, a series of painstakingly-produced photos interleaved with commentary is presented as exactly that, instead of as an unnavigable video!
Well, no comments means that there’s nothing contentious, nothing to spark outrage, and nothing that needs “correcting” by the hive brain. Just a good, solid article.
So I’ll leave this comment and another, just to bump up the numbers. (since I’m guessing that and adclicks are how ‘performance’ here is measured)
The purpose of HaD comments is to bash people’s projects, make openly racist remarks about Chinese people, and rant about how solar/wind/etc. are a scam and climate change isn’t real.
This is a really great article, though.
68 minutes after your comment a guy that doesn’t like lithium batteries compared Chinese people to coach roaches which I find ironic in a way (also incredibly sad). they ARE people just like use. and yes (like us) sometimes their morals are questionable.
on the quality of their products? quite good if they want them to be and are allowed to do that by management. ex: DJI, bambu labs (and essentially all Chinese 3d printers which is most of them).
I think living conditions over there are worse then they are in the US (based on very limited knowledge though) which is sad
That was a fake Dude.
It’s not a matter of “race,” it’s a matter of culture. So, are we “culturists” to note it. And, of course, it doesn’t describe EVERYONE who lives there:
Book: To Steal a Book Is an Elegant Offense: Intellectual Property Law in Chinese Civilization (Studies in East Asian Law, Harvard University) – 1997
One of several studies:
JOURNAL OF CHINESE ECONOMICS, 2014 Vol. 2. No. 2, pp 73-78
Call for Copy – The Culture of Counterfeit in China
by Ling Jiang
Abstract: The aim of this paper is to deepen the understanding of Chinese counterfeit phenomenon by exploring the effect of culture. Counterfeit activities are shaped by Chinese historical, social and political reasons. Intellectual property rights protections don’t have an obvious presence on Chinese soil. The discussion of counterfeit consumer behavior research via the effect of culture is provided.
Planted “lost wallet” return rate experiment by country. Note what country is at the very bottom of the resulting chart:
https://pbs.twimg.com/media/D9mk_d2UYAIpAdP.jpg
Go to Grok and ask, “Provide examples of scandals in mainland China where people were harmed by counterfeit items.”
Those are just the examples that attracted widespread attention. The concluding paragraph from Grok: “These scandals have driven regulatory crackdowns, yet counterfeiting remains a persistent issue, contributing to broader public health crises. For instance, global reports link Chinese-sourced fake meds to thousands of deaths worldwide, underscoring the need for ongoing vigilance.”
There’s a westerner who traveled in China for years on a motorcycle to make interesting videos for YouTube, some of which I watched, who produced a video about how they sell truly dangerous things in the Chinese markets after he and a riding companion became extremely ill from liquor bought off the shelf in a seemingly reputable establishment.
Comments are a bad metric for how good or interesting an article is.
So, it’s really documentation supporting the old adage: There is absolutely nothing in the world that some man cannot make a little worse and sell a little cheaper; and the people who consider price only are this man’s lawful prey.
Lumafield is a company who make money selling these fast CT machines, so the fact that the conclusions of the report is that we need to scan these cell because they are so dangerous, is pretty much in their best interests. That colors my reading of this report.
Come off it. Lumafield devices aren’t consumer accessible, and lithium-ion cells are dangerous. That we even get these scans for free to understand the variation in cell manufacture is a win.
Now, if you’re a company buying tens of thousands of cells and need a way to validate a supplier, one of these machines might be a very wise investment.
I dunno what possible benefit there would be to biasing this report in any particular way, especially since it’s already pretty much common knowledge that Panasonic cells are the best in the market.
Kevin, if you don’t recognize a marketing effort for what it is, that’s on you.
And if Lumafield is good at one thing, it’s marketing. There are better CT scanners. There are cheaper CT scanners. There are faster CT scanners. There are even better ways to do image reconstruction and analysis. But Lumafield has found a sweet spot in engineering, manufacturing and applications, and is cultivating a market for it. It is doing very well at it, where many others have failed.
You can’t fault them for that.
(I find fault for them giving one to Linus, but that’s just me)