Leaking Electrolyte from Bigbattery Powerblock

[Will Prowse]

They said the cells are new, and I'm asking for a data sheet stating capacity and ir value. Still haven't had a response. I don't think the cells are new. That is my opinion.

I have torn apart a lot of batteries and used them for years without one leaking. I have some sinopoly dinosaurs at 80% capacity and they dont leak. They have been cycled thousands of times.

I don't understand why they found 11 other leaking cells. They should have found zero. Sounds fishy.

 

[Gazoo]

How about laser welding? Is it possible that caused the cell damage? While BB may have inspected 100,000 cells, those were most probably fresh from the supplier. They surely did not open up every fully manufactured box to see if cells got damaged by the manufacturing process. I think they may end up needing to do that. For now it would be advisable to up their inspection game, way up. The chance that this was the luck of the draw at 10,000 to 1 odds is just way too remote.

Laser welding is a very common way to attach studs to cells and the Chinese have been doing it for years. Its my understanding Big Battery laser welds the studs themselves. But here we are a day later and neither Will or Big Battery has specifically stated the source of the leak.

I do agree the cells in the battery case should have better protection especially if used in a mobile environment. I am finding it hard to believe the cells came out of the Lishen factory leaking but I have been wrong before. We need to know the source of the leak and if there was any damage at the source that caused it, or something happened during the manufacturing process with the aluminum shell.

I don't know if you have watched the video HiTechLab posted of Big Battery's factory but here it is:

 

[Gazoo]

This is the only post I remember on this forum about cells leaking electrolyte .... I didn't do a full search, so there could be more.
Based on the leakage problem being rare .... and most people are mounting the cells vertically in their DIY packs .... I would speculate that horizonal orientation is not a good idea.

I am not advocating for this one way or the other. I am only going by what EVE said regarding this. I think we all agree if a cell leaks then there is a problem. A cell should not leak and this is the first time I have heard of a cell leaking as well.

NOTE: When they refer to electrolyte leak they are referring to the innards of the cell. It is not external.

Regarding that part I was thinking about internal leaking due to delamination of the jelly roll based on what I learned on this forum. When Ghostwriter spoke to EVE on the phone EVE never mentioned anything about leaking. I have learned much since I made that comment. However a cell should not leak even if held upside down. There have been many of us who have ordered cells from China. Thousands of cells ordered and shipped on a slow boat and not one has leaked as far as I know. Something smells fishy with the Big Battery episode.

 

[Gazoo]

They said the cells are new, and I'm asking for a data sheet stating capacity and ir value. Still haven't had a response. I don't think the cells are new. That is my opinion.

I have torn apart a lot of batteries and used them for years without one leaking. I have some sinopoly dinosaurs at 80% capacity and they dont leak. They have been cycled thousands of times.

I don't understand why they found 11 other leaking cells. They should have found zero. Sounds fishy.

When you have time could you try to find the source of the leak on your cell? As you know.....be careful.

I have the Lishen data sheet but it's in Chinese. Still easy to figure out and I believe it was you who posted it in another thread. Is this what you are looking for?

 

[DerpsyDoodler]

They said the cells are new, and I'm asking for a data sheet stating capacity and ir value. Still haven't had a response. I don't think the cells are new. That is my opinion.

I have torn apart a lot of batteries and used them for years without one leaking. I have some sinopoly dinosaurs at 80% capacity and they dont leak. They have been cycled thousands of times.

I don't understand why they found 11 other leaking cells. They should have found zero. Sounds fishy.

If they are lying about what they are selling, then that is fraud. It would be a very serious accusation, and perhaps something that needs to be reported to the FTC? They seem to be staying in contact with you, Will. Have you asked for a detailed explanation? Its not like you have any authority over them, but it is not unreasonable to want or expect an explanation. They have to be accountable to someone, if not you, then to whomever this may need to be reported to.

 

[Bob B]

I ran that PDF thru PDF Translator .... it didn't come out perfect, but is readable.

 

[Bud Martin]

I wonder how Will will ship the batteries back safely to BB to do failure analyzis.

 

[DerpsyDoodler]

I wonder how Will will ship the batteries back safely to BB to do failure analyzis.

Given all the speculation about wrong doing, it may not be going back to BB. That is potential evidence.

 

[Bob Steel]

I feel its pretty well established now that the cells you can buy from china are mostly refurbished cells. Likely initially used by the military and swapped when they get to something like 80% of initial capacity or 3 years whichever comes first. Cleaned up rewrapped hopefully tested for capacity and grouped together and that's why the variable capacities advertised for the same physically sized cells .

All the alloy cells I have examined inside have ethylene carbonate as the electrolyte and filling the cell almost to the top is one of the last manufacturing jobs through the vent hole before that too is TIG welded up. The top is TIG welded in first then the vent done after filling. ( maybe laser on some but I have not seen those yet)

So fluid running around is normal. They can be laid on their sides usually if they have been filled properly. The cells can leak if any part of the alloy case is stressed or damaged and I guess that's inevitable for a very small proportion of cells sold. You can smell a leak when you charge initially ,that sweet sickly smell and that should alert you.

Scratches on the terminals and bottom, pitting of the terminals and dents in the case are all signs of prior use. So each cell should be checked over before use.

Guy named Terry did a video of pulling one apart and there are a lot of pictures of a pull down here under media ,photos and maybe albums.

 

[Bob Steel]

Given all the speculation about wrong doing, it may not be going back to BB. That is potential evidence.

Well unless you can prove they knew they were second hand that's not likely to be a successful legal case. No one admits it over there Like all Chinese businesses Ali Express is government controlled and while they won't normally admit they are used cells they will give you an additional refund, if you insist they are used, against the sellers wishes . That says something in itself.

 

[DerpsyDoodler]

Well unless you can prove they knew they were second hand that's not likely to be a successful legal case. No one admits it over there Like all Chinese businesses Ali Express is government controlled and while they won't normally admit they are used cells they will give you an additional refund, if you insist they are used, against the sellers wishes .

Don’t know why I had it in my head that bb was American. I suppose there isn’t much recourse other than an “avoid like the plague” campaign?

 

[solarbot]

...Is it to prevent expansion of the cells for longer cycle life?

Is it to squeeze electrolyte up into the top of the cell?

the cell will “breath” like people does

Why do I get the feeling that this reply is not authoritative?

 

[Bob Steel]

I just took an aluminum case cell and measured voltage from negative terminal to the case - 3.2v.

So I put my meter into ohms mode and checked between + terminal and the case - 110 ohms.

Based on ohms law, let's say worst scenario we had somehow gotten 20v potential on the case because cell 1 + is connected to cell 8 case, now we have 3.6 watts of power doing something. My theory is that it is reacting with the aluminum case and causing pitting. Over the course of a month, that could mean a hole in the case.

I sell batteries, similar to the ones in the 24v powerblock from BigBattery, and I am considering revising my manual to recommend a plastic separator between each cell. I am no longer convinced that the thin film on the cases is good enough for insulation, even though the connection between the case and the positive terminal is a really high resistance. I am tempted to do some more destructive testing on cells - apply voltage from the + terminal to the case and see what happens over time. Will it cause pitting and a pinhole to form? Might be a very interesting test and video to make and share with the community.

Yes I have found the same but not on all? The electrons must be flowing from the negative terminal through the electrolyte ? or is it ions flowing? Do you know?

The other factor to take into account is impurities in the alloy . All alloys have such impurities and you will be familiar with alloy boats which sit in salt water and pit through as salt trys to get to fresh inside the bilges.

 

[Gazoo]

Don’t know why I had it in my head that bb was American. I suppose there isn’t much recourse other than an “avoid like the plague” campaign?

The factory tour I posted above is in California. They assemble everything in the USA but get the cells from China...like everyone else.

 

[Bob Steel]

Is it to squeeze electrolyte up into the top of the cell? NO

Why do I get the feeling that this reply is not authoritative? Yep sounds like garbage.

The cells are not compressed but rather restricted to prevent or slow expansion of the cells by overcharge /overdischarge of the cell causing heat in the center of the cell which causes the electrolyte to turn to gas and expand with dramatic force.
Some form of spacer between the cells makes sense to promote air flow and cooling and a box out of non conducting material like plywood and on the bottoms also.

 

[Gazoo]

Is it to squeeze electrolyte up into the top of the cell?

Why do I get the feeling that this reply is not authoritative?

The reply I received from EVE came from one of their techs. So yes it is authoritative but he could have gone into more details and we must remember they use a translator. A translator was not necessary when Ghostwriter spoke to the EVE tech because she speaks Chinese and she was able to get much more information and details than I did.

In a nutshell compression is supposed to help prevent delamination of the jelly roll which in turn increases cycle life. It has nothing to do whatsoever regarding cell leakage. I have seen posts of severely bloated cells due to overcharging and none leaked. The vent didn't even open.

 

[DerpsyDoodler]

The factory tour I posted above is in California. They assemble everything in the USA but get the cells from China...like everyone else.

Yet...not everyone else is having these problems..I am less inclined to blame the cells (not that they couldn’t be the culprit). Anyways, that’s more speculation. I am more interested in getting to the bottom of this.

 

[Gazoo]

Yet...not everyone else is having these problems..I am less inclined to blame the cells (not that they couldn’t be the culprit). Anyways, that’s more speculation. I am more interested in getting to the bottom of this.

I am too and hopefully @Will Prowse will look at his cell and determine where the leak is. I would think he is interested and would also be interested in the well being of anyone who ordered from Big Battery.

 

[solarbot]

I ran that PDF thru PDF Translator .... it didn't come out perfect, but is readable.

Indeed it is. I found "It is strictly forbidden to weld the battery directly."

(edit) "The battery case is positively charged. It is strictly forbidden to connect the negative pole of the battery and the battery case directly to form a path during use.This will cause the battery to short circuit, which may cause the battery to catch fire or even explode"

...or maybe leak electrolyte?

 

[Alkaline]

Just goes to show all this "GRADE A" gunk UL listed talk is all BS, its the same cells you get from any where else, I remember seeing a video claiming Big Battery has a million lishen cells... Sure, I doubt they have more than 1000 cells.

Bottom line is, folks this is the same stuff everyone else is getting, best insurance is to buy some spares and just roll with it, if a cell goes bad, replace it with something else.