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CT scans of 1k lithium-ion batteries show quality risks in inexpensive cells

(www.lumafield.com)
287 points jonbruner | 17 comments | 24 Sep 25 19:29 UTC | HN request time: 0.001s | source | bottom
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bahmboo ◴[26 Sep 25 23:58 UTC] No.45392244[source]▶
Seems like a good time to highlight this video from Grin Technologies and their experience with ebikes over the years.

https://www.youtube.com/watch?v=j92Gt4VviSQ

Summary Statement: He summarizes the results of the "sabotaging" attempts by saying, "we just couldn't for the life of ourselves get a nonprotected modern lithium battery to do anything" [02:40:27], in terms of causing a fire. (referring to 18650s)

There are certainly problems out there with cells but it was a surprising statement from someone with a ton of real-world experience. Also they are a very conscientious company so they don't deal with dodgy stuff if they can avoid it.

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1. bahmboo ◴[27 Sep 25 03:42 UTC] No.45393069[source]▶
It's a long video but one takeaway is to only use cells from the top manufacturers: Samsung, Panasonic, LG and Sony. They are amazingly safe.
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2. eth0up ◴[27 Sep 25 04:08 UTC] No.45393150[source]▶
Molicell?

I have one in 21700 and it seems a great battery so far. Otherwise I'm a Panasonic guy.

I ask because it sits on my forehead, inside a headlamp. Having my hands tied, addressing a problem quickly might be difficult. And them rascals get toasty fast when they ignite.

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3. lambda ◴[27 Sep 25 06:26 UTC] No.45393591[source]▶
Yeah, Molicel are quality cells as well.
4. bahmboo ◴[27 Sep 25 06:54 UTC] No.45393687[source]▶
The anecdata is Molicell is good stuff. Was going to include that but I have no references.
5. mixedbit ◴[27 Sep 25 08:22 UTC] No.45394053[source]▶
Unfortunately, for products with batteries in non-standard form factors, we rarely have a choice of a manufacturer. For example, with home robot vacuums, we can only hope that brands will use top quality cells, but the information what cells are used is not even available to the customer. My Neato vacuum still runs great, but now that the company is out of business, my only battery replacement options are from no-name brands, with zero visibility of what cells are used internally.
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6. consp ◴[27 Sep 25 08:57 UTC] No.45394226[source]▶
Unfortunately the cheap "fatbikes" every kid has here these days have no premium cells and even worse chargers and usually poor or no balancing in the BMS. I don't expect them to not catch fire and my HOA is considering to ban charging ebikes in the basement (where you put your bike) due to that. End result is likely that people with more expensive bikes and cells adhere to this and charge in the house while the cheap ass bikes will still be charged in the basement and the fire department can flood it once again when it all goes up in flames.
7. avar ◴[27 Sep 25 09:19 UTC] No.45394334[source]▶
You also have the option of building your own battery pack for these, or to disassemble an existing pack and replacing the cells. How difficult that is depends on the manufacturer, but from a quick look at the Neato packs I see it looks relatively trivial.
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8. rollcat ◴[27 Sep 25 09:35 UTC] No.45394382[source]▶
> For example, with home robot vacuums, we can only hope that brands will use top quality cells, but the information what cells are used is not even available to the customer.

Hardware used to come with diagrams & schematics, for self-service and repair. This was a courtesy, but I guess manufacturers figured out it's better to make the consumer buy a new model. (AKA part of the reason why Commodore went bankrupt.)

Meanwhile we've been talking and implementing measures such as lists of ingredients and nutrients in food, SBOMs in software, privacy/tracking transparency, etc. Let's push it a little further.

9. fnordian_slip ◴[27 Sep 25 09:56 UTC] No.45394465[source]▶
lygte-info.dk rates them quite highly iirc.
10. jdietrich ◴[27 Sep 25 10:22 UTC] No.45394578[source]▶
Molicel is top tier - their P50B is the best 21700 cell available on the open market. Eve, BAK and Ampace also make some really good stuff, although they can't match the performance of Molicel.
replies(1): >>45397328 #
11. stavros ◴[27 Sep 25 10:42 UTC] No.45394657{3}[source]▶
I'm in the process of replacing the battery in my old robot vacuum right now, and for the amount of time spent doing that, I could buy a whole new vacuum. It's a pity, because the battery itself can be replaced just by plugging it in, but all the batteries I could find were AliExpress fakes, so my two options are either "more e-waste" or "spend $500 in time doing it myself".
replies(1): >>45396133 #
12. avar ◴[27 Sep 25 14:43 UTC] No.45396133{4}[source]▶
Some of us enjoy fixing things like these over and above the hypothetically fungible billable hour, and whether you can substitute some time in an evening with a billable hour or three is highly dependent on your employment situation.

But in this case the relevant cost under discussion isn't that of a replacement vacuum cleaner, but what value you assign to your house not burning down due to a crappy 18650 cell, or the anxiety of worrying that that'll happen.

replies(1): >>45396261 #
13. stavros ◴[27 Sep 25 14:58 UTC] No.45396261{5}[source]▶
Well, I don't enjoy making the hundredth battery pack, so I'm counting it against the hypothetically fungible billable hour.

The cost should be the cost of a good-quality battery pack from the factory, which I can only get right now as part of the vacuum, unfortunately.

14. Adachi91 ◴[27 Sep 25 16:39 UTC] No.45397328{3}[source]▶
I came to the same conclusion when upgrading from 18650s to 21700s, I spent a long time trying to weed out the poorly binned rewards, and the minefield of lithium batteries. They weren't cheap but have been happy with their performance.

There are a lot of people out there that see 18650 or 21700 and think a lithium ion battery is a lithium ion battery and they're all the same (i.e. trying to pull 20 amps from a 2 amp peak battery). I miss one of the father's of liion battery education, Mooch (from ecigarettes forum) who had a whole methodology of testing, and educating people.

15. leptons ◴[27 Sep 25 19:40 UTC] No.45398749[source]▶
I imagine the counterfeit market for lithium batteries is quite large, so maybe not always amazingly safe.
16. CamperBob2 ◴[28 Sep 25 00:15 UTC] No.45400562[source]▶
I ask because it sits on my forehead, inside a headlamp. Having my hands tied, addressing a problem quickly might be difficult

Gotta ask what kind of sport, profession, or B&D game involves wearing a headlamp while your hands are tied.

17. FeepingCreature ◴[08 Oct 25 15:08 UTC] No.45517037{3}[source]▶
I don't think "you should build your own battery pack" is the sort of advice that will on net reduce house fires.