Rattle in a cell

Ok, they arrived, that's already good news.

you're first test has similar result as mine, still at 2100mA for a 2200mA cell, not heating, and holding charge, whichis really good.

Since I have around 30 cells like that, I hate to disgard them.

Good luck with the X-ray. I think most dentist nowadays use digital X-ray, so should be easier to view (or upload) the image.

patiently waiting for more results.

best regards.

Stefaan
 
OK guys, x-rayed the cells, but you can't see very much on the pics:


image_eugatr.jpg


image_mfmtqv.jpg


image_uxywip.jpg


On the 2nd pic, there's a small pin at the bottom of the cell and I think this pin got loose. What do you think?

One more thing I noticed: A cell fell down when I was placing it under the x-ray device and after that, it wasn't rattling any more... very< strange. I then dropped it again intentionally and it rattled again...

I hope I have time to open one of them tomorrow, but I want to film it for you and must prepare my video equipment before. Never did this for a long time...

I'll get back to you as soon as possible :)
 
I wonder if the cathode pin came loose some how. It's obviously still making contact with the carbon in the center, otherwise there'd be no electron flow. Hmm....

Can't wait to see what you reveal in the video, owitte!
 
Nice to see your dentist is not going digital, looks like classic X-ray. problem is taking the picture of the x-ray.

I also noticed that sometimes the rattle stops, and comes back after a good shake.

I think I even have tested cells that I didn't even check for rattle.

Very curious about the cutting open and the video.

best regards

Stefaan
 
StefaanDeRidder said:
Nice to see your dentist is not going digital, looks like classic X-ray. problem is taking the picture of the x-ray.

I also noticed that sometimes the rattle stops, and comes back after a good shake.

I think I even have tested cells that I didn't even check for rattle.

Very curious about the cutting open and the video.

best regards

Stefaan
Click to expand...

it's a classic small x-ray device, but a digital film. After making the shot, the film is scanned digitally. Fast, easy and clean, no chemicals at all.

Btw, I just discharged one of the cells to 0.5V with a 5W resistor and charged my old GoPro Hero 2, hope I'll find some time tomorrow for opening the cell :) .
 
that image on a black T would be awesome i think
 
And then add 18650ED on the cell :)
 
Hi there!

Finally I had time to open one of the cells Stefaan sent me. And I found this in the middle of the "foil roll":



image_jlgbdy.jpg

image_vkueln.jpg


I think this piece of metal was used in the production process to roll the foil layers. It should have been sticked or glued to the inner end, but somehow got loose and caused the noise. If you're interested in the complete opening of the cell, check out the very first video I made :shy: :


Hope you like it...

@Stefaan: I think you can use the rest of the rattling cells without a risk, if they measure ok :) .

Have sun!
Oliver
 
wow, cool finding, and a very nice first video

I first thought the pin or tube should have been the anode, and was connected to the positive side.

But I've found a presentation of the inner parts of an 18650 cell, and there is no 'pin' inside.

So I might be possible that this piece of tube is just part of the rolling of the layers proces.

very interesting to see a cell being opened with such care.

and just because it behaves as a normal cell, charging, discharging, holding voltage, I also think that there is no reason for not using them

Thanks Oliver for your time and video

best regards

Stefaan


image_hjdrdi.jpg
 
In my case, i opened an hp laptop battery, and found 2 cells rattling like in the video. The cells are samsung ICR18650-22F
 
I have one cell as well that rattles. From an oe laptop cell. Tested perfectly good. Sounds like a bb inside a tube. Thanks for video as now I do not need to cut open to investigate
 
Stefaan,
Did you use the cells? Did you have problems with it later on?
I also have cells from an e-bike pack that rattle (in total almost 100 cells) but if they are safe to use it would be nice :)
Thanks
 
I openened Stefaan's cells and found the cause for the weird noise. As far as I could see, it's save to use them.
 
Hello owitte,
I saw your video (very helpfull) but i wanted to know if there were no problems with the cells at a later point in time :)
 
I keep reading the title - Rattle in a cell - and I just have to shake my head. Its always so amazing to read about something new / that you'd never imagine could happen. I don't have a "shake the cell" and "listen for a rattle" step when I process my cells... so maybe I have hundreds of them. Love this thread and overall site. :)
 
Registered just so I could comment. Cant thank you guys enough. This thread was so refreshing, so different than so, so many experiences slogging through brutal threads on misc sites trying to answer some obscure problem. You guys rock! I mean, xrays? lmao... too cool. Because of your awesome communication and cooperation, i no longer need to split open this battery, nor do i need to spend any more time researching. Thanks again, and stay rad. Peace friends.
 
It looks like the rod not an active part of the cell, but like Oliver suggests, just a former to make the roll neat.
Maybe it helps reduce shorts in the middle of the cell by "controlling the edge" in the centre of the roll or something like that?
As Oliver unrolls the layers, about halfway you can see a white strip - this is most likely the current connection point, it's half way from each end which makes sense for the distributed current flow. This also suggests the post is not active electrically.
I took apart a cell a while ago & don't recall it having this centre post - my cell might have been a different construction.
Maybe it's a high current cell vs laptop cell build thing?
 
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