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

lumafield.com

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

#21

Post by jeffbee »

dylan604 wrote: post #17
jeffbee wrote: post #15

Earlier quoted context omitted.

It does help. It raise the opportunity to discuss it, which is helpful because not everyone is aware that this is a problem, and like many other lease clauses it is there to assign blame in case an exceptionally bad event comes to pass.

Nah, tenants will sign just to move in, and forget about this clause. Just like any tenant that smokes weed disregards no drug clauses. Tenants are going to do what tenants do. Unless you're doing routine walk throughs looking at every single thing in the place that could use a battery, then you'll never know. It's a useless "regulation", and we have plenty of those in the world already.

It's wrong to have an unjustified low opinions of tenants as a class. They are normal, well-meaning, intelligent people like any other.

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

#23

Post by jacquesm »

amelius wrote: post #18
oulipo2 wrote: post #8

After we monitored many battery fires, we decided to build a casing which can sustain lithium fires for typical e-bike batteries: https://www.youtube.com/watch?v=v0NXXfCA2CY

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.

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

#24

Post by trebligdivad »

jeffbee wrote: post #15
ReptileMan wrote: post #13

Earlier quoted context omitted.

Won't help much. Way too much cheap lithium ion crap with incapsulated batteries is flooding the markets

It does help. It raise the opportunity to discuss it, which is helpful because not everyone is aware that this is a problem, and like many other lease clauses it is there to assign blame in case an exceptionally bad event comes to pass.

It's got to be tricky for people to know what cells they have inside their {phone, toothbrush, bike etc}.

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

#25

Post by jacquesm »

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.

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

#26

Post by jacquesm »

ReptileMan wrote: post #13
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.

Won't help much. Way too much cheap lithium ion crap with incapsulated batteries is flooding the markets

Yes, especially wearables and toys. Those are a real problem. One of my kids was gifted a toy that had an embedded Lithium Ion pouch battery of spectacularly bad quality, the pouch had already inflated to the point that it was unsafe to dispose of when he got it. I ended up hand delivering the whole thing to the local disposal site where they have the proper gear to deal with these.

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

#27

Post by josephg »

jacquesm wrote: post #25

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 looki…

> 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.)

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

#28

Post by joecool1029 »

quickthrowman wrote: post #19
Neywiny wrote: post #4

I find their table of advertised vs actual capacity to be misleadingly negative. They only discharged to 3v. 2.7 could be viewed as more standard. 2.5 is not unheard of. For example, the vapvell 4000 they said was around 3000. They even have a note that says that isn't a reasonable capacity estimate. And yet they still put the percentage and the number. As if they've falsely advertised. However, if you go to vapcell'…

How do you even drain a 3.7V lithium ion battery below 3.3V? My devices that use 18650s will not let them go below that. Is it 3.3V nominal and the actual voltage is lower, like how they’re 4.2V fully charged?

I guess leave them sitting in a laptop in a barn for a few years. I was given some old shit gateway the other day, tried to charge it, no dice. Ripped the pack apart to find samsung 18650's with approx 0.7V voltage.

Against ALL recommendations I put these cells into a MC3000 and they charged up just fine to 4.2V. It does a 0.15A charge per cell until it gets above 3V. Then I had it set to 1.92A bulk charge. Fire extinguisher nearby lol

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

#29

Post by quesera »

jeffbee wrote: post #21
dylan604 wrote: post #17

Earlier quoted context omitted.

Nah, tenants will sign just to move in, and forget about this clause. Just like any tenant that smokes weed disregards no drug clauses. Tenants are going to do what tenants do. Unless you're doing routine walk throughs looking at every single thing in the place that could use a battery, then you'll never know. It's a useless "regulation", and we have plenty of those in the world already.

It's wrong to have an unjustified low opinions of tenants as a class. They are normal, well-meaning, intelligent people like any other.

  s/tenants/humans/g
The large majority of tenants do not read their lease paperwork carefully enough for this clause to make a difference.

A large majority of humans don't read EULAs.

A lease clause is useless for liability, because your landlord's insurance won't be able to shake down the tenant anyway.

Someday soon enough, your insurance might require a clause like that. It will still be ignored by tenants though.

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