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Discussion Starter · #1 ·
Aloha, I have clamped my 160ah used TS's on the bench because they were a wee bit swollen on the sides. With two all-thread rods I made a clamp and clamped 18 cell together and used enough torque by just using a deep socket by hand to tighten it up and the cells are pretty much flat. (I did not use a rachet, just my hand on the socket to explain I did not have to tighten very much to get 'um flat). Question is, "now what". I take the clamp off and the cells pretty much go 50% back to swelled. Do I just put them into the car and clamp them and forget it ? Voltage is still right on at 3.35v each since i top balanced them.


thanks
francis
 

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Do I just put them into the car and clamp them and forget it ?
Yes, that's my understanding. It frightens the willies out of me what must be happening inside a cell to cause swelling, but the manufacturers seem to be quite relaxed about it.
 
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Gassing and squeezing them won't fix the problem. What's happening is either your overcharging or over discharging.

If you top balance your cells and drive them until they start to drop like a rock you could be driving a cell or more into the zero level and at that point the cells are heating up real fast and hot. You basically boil them to death. If allowed to go to far you loose your cell. If you over charge them the same happens.

The cells swelling are telling the story. You can't hide that you either overcharged them or were driving them into the ground by the batteries ending the charge before the rest and being driven into the zero point.

Can't fix swelling. Sorry. Properly charge them to 3.6 or so and don't let them go below 2.9 static voltage. At that point the drop is fast. It has been proven. don't disregard the issue.

Bottom balance your cells to like 2.8 then charge them until you get to 3.6 volts per cell. You may have a few up in the upper end but all cells have a different capacity. No cells have the same capacity.


Watch this video. http://media.ev-tv.me/news111309-1280.mov
 

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What's happening is either your overcharging or over discharging. ... Can't fix swelling. Sorry.
Well, I guess one of us is wrong. I'm just going by the fact that the manufacturers say that swelling is inevitable if the cells aren't clamped, and that no permanent harm is done.

Also, I've observed swelling with what I consider to be normal (well within specifications) treatment. If I'm wrong, I'd sure like to know about it.
 

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Well, I guess one of us is wrong. I'm just going by the fact that the manufacturers say that swelling is inevitable if the cells aren't clamped, and that no permanent harm is done.

Also, I've observed swelling with what I consider to be normal (well within specifications) treatment. If I'm wrong, I'd sure like to know about it.
Where did you read manufacturers saying this? In lithium batteries, you have electrolyte which shuttles Li+ ions between the cathode and the anode. The electrolyte can undergo electrolysis and be split into gasses if the voltage exceeds 4.2V just like water can be split into hydrogen and oxygen. The electrolyte will undergo natural degredation but that reaction is very slow so your cells shouldn't swell by themselves for at least 5 years. Once you create those gasses, there's no coming back. Although your capacity might remain about the same, the internal resistance of those cells shoots through the roof as Lithium ions can't move very easilly and the batteries become very easy to overheat. Clamping them will help some as you decrease the distance between the cathodes and the anodes but your cells are on their way out.
 
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This is a result of over discharge due to one battery being driven to the ground because my pack was not properly bottom balanced. It was more like mid balanced. The one cell reached the knee long before the others and the others drove it into the ground. The cell however is not dead. But it was extremely hot and bloated when I got back to check the batteries. It happened before I balanced the cells better. Now none get hot towards the end of the drive and all are very close in voltage too.

This is what happens when you have a top balanced pack and you have a cell that has a lower capacity than the rest and it reaches that level long before the others. The others will drive it to the ground.


It is a Hi-Power Cell.

The cell still holds power. I am thinking of pressing the cell and then melt a small hole in the cell to relieve pressure then reseal the cell and see how that works. I will do a discharge test to see if it has the same capacity or if it has lost a bunch or none.
 

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The cell still holds power. I am thinking of pressing the cell and then melt a small hole in the cell to relieve pressure then reseal the cell and see how that works. I will do a discharge test to see if it has the same capacity or if it has lost a bunch or none.
Ooh, I'd recommend against it. Next time you cause even a tiny bit of gassification, your seal will break and the electrolyte will leak out. You can cause quite a bit of pressure inside these cells. Props on the bottom balance though.
 

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Thank you, gottdi for the video! Was great, haha. Lots of good knowledge, definitely going to be checking out that site a lot from here on out.

SIMPLE QUESTION
I've heard of liquid cooled LiIon battery packs, but what about lead acid battery packs. Do they get hot as well? Can't find too much about lead acid battery packs as far as cooling goes, so I'm even unsure if they need cooling.
 
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Yes lead acid batteries can get hot too. But if you drive them or charge them properly they won't. They will get warm. Warm is fine. Melting hot is not.

Every one should be watching Jacks videos. You don't have to agree with all he says but he backs up his claims with real information. Better than many around these forums.
 
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Ooh, I'd recommend against it. Next time you cause even a tiny bit of gassification, your seal will break and the electrolyte will leak out. You can cause quite a bit of pressure inside these cells. Props on the bottom balance though.
For testing and I can seal it up tight. I plan on using heat not drilling out plastic. I have done this before on other things. Some times it works sometimes not. Just going to try. Can't hurt because the battery won't ever be used in an on the road EV. Maybe in a lawn mower but not on the street.
 

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Yes lead acid batteries can get hot too. But if you drive them or charge them properly they won't. They will get warm. Warm is fine. Melting hot is not.

Every one should be watching Jacks videos. You don't have to agree with all he says but he backs up his claims with real information. Better than many around these forums.
Tank ya', mate. Yeah, he somewhat reminds me of Alex Jones, heh, which could be bad, but I do enjoy his demonstrations that then back up his knowledge. That and he has a nice taste in cars. :rolleyes:
 

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Discussion Starter · #15 · (Edited)
That is an interesting thing to note. How much have they swollen? Have they swollen like this?
Whoa, no way near that much. If you put two of your HP swollen cells side by side, I guess they probably would measure 1 inch apart. With mine, two cells together, they would measure 1/4 inch. I bought my 160ah cells that were used and came from a testing facility (so the seller says), so I do not really know the history, but I am treating them properly now. We will see I guess.

Francis
 
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Got some interesting news. The swelling is not from gassing within the cell. It is a physical change that causes the swelling. I will be taking video and photos of my Hi-Power I dismantled that was at 0 volts and totally swollen like the one in the above photo. I chose this one to open because it had no chance of shocking me during the opening of the cell. Again, swelling like I suspected is not from gas but from a physical change that causes swelling.

Pete :)
 

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Discussion Starter · #19 · (Edited)
Got some interesting news. The swelling is not from gassing within the cell. It is a physical change that causes the swelling. I will be taking video and photos of my Hi-Power I dismantled that was at 0 volts and totally swollen like the one in the above photo. I chose this one to open because it had no chance of shocking me during the opening of the cell. Again, swelling like I suspected is not from gas but from a physical change that causes swelling.

Pete :)
Hi Pete. and do you think this change is detrimental with ANY Swelling or do cells swell for whatever reason and progressively become less efficient until they are 0volts? TS does mention the clamping device, (but then again they mention charging at 4.2 volts too.)
 
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Cells do not swell for no reason. Swollen cells are not good. Not that they loose all capacity but you won't get them flat again. At least not that I am aware of anyway. Maybe a full charge and discharge under pressure will help lessen the swollen battery issue but damage is done when batteries swell as they have been either overcharged or over discharged. Neither of which is good. Actually the over discharge is more like when you drive a cell into the ground and it also overheats. If you slowly discharged a cell to zero I'd almost bet it wont swell. But overcharging which goes along with overheating will cause swelling and over discharge (drive to the ground) includes overheating also. Swelling will occur. But its not gas that causes the swelling.

Pete :)

I will have the movie in HD on youtube tomorrow but until then I have one you can look at with your phone or browser. Works with quicktime too. It is smaller but my server is kinda slow for large format movies. Until it has completely uploaded this one will have to do. Once loaded you can save it too until I have the youtube one available.

http://greenev.zapto.org/GreenEV/GreenEV/GreenEV_Productions_Albums/Pages/Hi-Power_Movie.html

Photos too are up.
http://greenev.zapto.org/GreenEV/GreenEV/GreenEV_Productions_Albums/Pages/Hi-Power_Photos.html
 
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