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

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

#51

Post by eth0up »

bahmboo wrote: post #50
bahmboo wrote: post #36

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 ar…

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.

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.

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

#52

Post by gertlex »

MBCook wrote: post #40
gertlex wrote: post #38

Earlier quoted context omitted.

FWIW I found the report's summary (a few days ago when this was also discussed) essential for clarifying for me what the linked "article" was talking about regarding "anode overhang" and "edge alignment". To summarize it myself, the battery is cylindrically wrapped sheets of anode/cathode material, and you want the top edge to have a straight line consistently having the anode layers (|) sticking out beyond the catho…

So the big danger here is an internal short being far more likely?

That was my general sense. And that "nominal" is really easy to identify visually with a (relatively slow) scan. I'd guess that means it's a clear quality control thing you (i.e. battery pack makers who are buying the cells) can expect the better manufacturers to do, and pay a slight premium for.

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

#53

Post by AtlasBarfed »

I get they won't disappear entirely, but what are the applications that 200-225 wh/kg LFP and forthcoming 175 wh/kg sodium ion can't handle with their much better safety profiles?

For higher density applications, semi-solid state is coming for nickel/cobalt chemistry lithium ion, and it has much better fire safety.

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

#54

Post by kragen »

AtlasBarfed wrote: post #53

I get they won't disappear entirely, but what are the applications that 200-225 wh/kg LFP and forthcoming 175 wh/kg sodium ion can't handle with their much better safety profiles? For higher density applications, semi-solid state is coming for nickel/cobalt chemistry lithium ion, and it has much better fire safety.

Drones seem like the biggest one? Maybe some drones can cope with the extra weight.

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

#55

Post by kragen »

jacquesm wrote: post #23
amelius wrote: post #18

Earlier quoted context omitted.

Maybe complement that with a CT-scan of your batteries and AI to detect defects.

FLIR monitoring + Ri measurement is a much better predictor than a CT scan, especially because you're not going to do that continuously.

Ri is internal resistance?

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

#56

Post by kragen »

xattt wrote: post #39
kg wrote: post #34

Earlier quoted context omitted.

My understanding is that material composition can make a CT scan take a really long time. It makes sense to me that scanning a battery would be pretty slow, given what they're made out of.

I just assumed it would be impractical due to physical changes of the object from multi-hour exposure to X-ray energy.

I don't think ionizing atoms inside a battery will harm it. They don't have DNA.

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

#57

Post by kragen »

jeffbee wrote: post #12

I just got a new tenant in my rental house and this time I had to add a clause to the lease enumerating brands of lithium-ion batteries the tenant is allowed to keep on the premises. These things are basically grenades that you can buy for $2 on Temu. Stronger regulations needed.

I found out today that the rechargeable batteries in my cordless landline phone are basically fake. They're NiMH AAAs, Highpower brand. I bought replacements because they were dying, and the replacements (rewraps by a domestic importer) weigh twice as much, 13 grams instead of 7, and purport to have 1000mAh capacity instead of the 300 advertised by the Highpower cells. Hmm, maybe that's why the phone wasn't working very well...

But those are (probably!) NiMH. No idea what brand of lions are in this cellphone, my laptop, my other laptop, my MicroPC, my other cellphone, etc.

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

#58

Post by lambda »

eth0up wrote: post #51
bahmboo wrote: post #50

Earlier quoted context omitted.

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.

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.

Yeah, Molicel are quality cells as well.

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

#59

Post by bahmboo »

eth0up wrote: post #51
bahmboo wrote: post #50

Earlier quoted context omitted.

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.

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.

The anecdata is Molicell is good stuff. Was going to include that but I have no references.

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

#60

Post by mixedbit »

bahmboo wrote: post #50
bahmboo wrote: post #36

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 ar…

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.

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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