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

(www.lumafield.com)
287 points jonbruner | 3 comments | 24 Sep 25 19:29 UTC | HN request time: 0s | source
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jacquesm ◴[26 Sep 25 22:34 UTC] No.45391694[source]▶
Your best predictor of cell failure is brand + where you sourced it. Good brand cells sourced through a reliable channel are pretty much impossible to get a failure out of without gross abuse of the cells.

But far more dangerous than single cell failure is pack failure and there the quality of the welding and the balance wires is probably a much bigger factor than bad quality cells. You can easily create a nice looking bomb from grade A cells, and even manufacturers with good name recognition will mess this up from time to time.

So buy packs made with quality cells and ensure that whoever makes the pack has proper welding gear and QA in place to avoid surprises. Never ever use cells without a BMS unless they are in a 1S configuration.

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1. josephg ◴[26 Sep 25 22:41 UTC] No.45391760[source]▶
> So buy packs made with quality cells and ensure that whoever makes the pack has proper welding gear and QA in place to avoid surprises. Never ever use cells without a BMS unless they are in a 1S configuration.

How do you put that advice into action? When I'm in an electronics store, they don't typically let you look at the welds inside each battery bank. (And if they did, I have no idea what I'd be looking out for.)

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2. jacquesm ◴[27 Sep 25 00:11 UTC] No.45392305[source]▶
Good point. It requires disassembly, and if you're not comfortable with that it is a lot harder to get a good idea on this. But there are plenty of videos and photos online of various disassembled packs from high volume manufacturers.

Quality cells are a relatively small group of brands so that should be easy enough to check for, and you'll know looking at just one side of a cell group whether or not it was put together half decently or whether it is messy.

Stuff to look for: loose balance wires, bad welds (welds that don't penetrate so they're loose), pointy edges of connecting strips that touch the plastic insulation of the cells, insufficient spacing between the cells, insufficient insulation near the welds.

For one-off purchases this won't help, but if you are a reseller or larger purchaser then it definitely is a good idea to tear down a pack and inspect.

3. askl ◴[27 Sep 25 14:37 UTC] No.45396072[source]▶
Your could take your CT scanner to the store to look at the cells.