Swollen Grade A MB31
- Thread starter Kornbread
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Quattrohead
Emperor Of Solar
Swollen grade a... No such thing end of.
ConnerLabs
Solar Enthusiast
Is this EVE's official Youtube, I think not!
Brucey
Velcro Man
"Starmax"...
Brucey
Velcro Man
well they had three versions of the 280k, third times the charm...maybe m30 model is actually the 280k v4..., polishing a turd?
meetyg
Solar Addict
- Joined
- Jun 4, 2021
- Messages
- 1,516
I think you guys are being a bit too hard on EVE and these guys...
First, the fact that these guys took the time and effort to address the issue and make a video about it is respectable, in my opinion.
I mean they could have just replied to thier customers saying "it's within the specs, everything is OK". That's what you'd expect from a Chinese company at the most...
Like how many times have we heard these types of companies blowing off thier customer complaints with a laconic reply that is of no help?
Second, the swelling/bloating doesn't look that bad. I've seen grade B/C (whatever you want to call it...) cells. It's worse. In used cells, the swelling is a tell-tale sign of abuse (usually over-charging or excessive heat).
But with slight swelling on new cells, it's not the same.
Thier explanation sounds logical: It's a tolerance that is part of the manufacturing process. If you ever looked at the datasheets for these cells (not only EVE), you will notice that they state tolerances for almost all of the parameters. If it's within the spec, I can accept that.
Anyone who has even the slightest knowledge of manufacturing processes knows that nothing is perfect and no product is 100% cloneable. Even when machines build the product, the machines themselves have tolerances or degrees of freedom, which can also affect the products being manufactured.
Here we are talking about a product that is pretty complicated to produce consistently, since we are talking about chemistry and things made by mother nature...
I personally think it's pretty amazing that they are able to mass produce so consistently.
But again, nothing is perfect, that's why they test each and every cell, to make sure it's up to spec.
Defining these tolerances is a complicated part of engineering. But they do that and give a warranty based on it.
Now for this "Starmax" company: I don't know them, but I don't think they would lie just to make themselves give you a discount!
I mean like I said, they could have made the same video, showing you that everything is up to spec and basically tell you not to worry and demand that you pay the full price for the slightly swelling cells.
But no, they opted to give a discount just because we, the customers like to see flat cells. I think that says something about their reputability.
If I was in the market for buying these larger cells, I think these guys would be on my list...
Of course I could be entirely wrong about them. Maybe they are total frauds. But only God knows the true intentions of mankind. We can only judge by what is presented in front of us.
This is my judgment from the video...
P.S. You gotta love thier choice of wording "ultra thicker"... Sounds worse than it is... LOL.
First, the fact that these guys took the time and effort to address the issue and make a video about it is respectable, in my opinion.
I mean they could have just replied to thier customers saying "it's within the specs, everything is OK". That's what you'd expect from a Chinese company at the most...
Like how many times have we heard these types of companies blowing off thier customer complaints with a laconic reply that is of no help?
Second, the swelling/bloating doesn't look that bad. I've seen grade B/C (whatever you want to call it...) cells. It's worse. In used cells, the swelling is a tell-tale sign of abuse (usually over-charging or excessive heat).
But with slight swelling on new cells, it's not the same.
Thier explanation sounds logical: It's a tolerance that is part of the manufacturing process. If you ever looked at the datasheets for these cells (not only EVE), you will notice that they state tolerances for almost all of the parameters. If it's within the spec, I can accept that.
Anyone who has even the slightest knowledge of manufacturing processes knows that nothing is perfect and no product is 100% cloneable. Even when machines build the product, the machines themselves have tolerances or degrees of freedom, which can also affect the products being manufactured.
Here we are talking about a product that is pretty complicated to produce consistently, since we are talking about chemistry and things made by mother nature...
I personally think it's pretty amazing that they are able to mass produce so consistently.
But again, nothing is perfect, that's why they test each and every cell, to make sure it's up to spec.
Defining these tolerances is a complicated part of engineering. But they do that and give a warranty based on it.
Now for this "Starmax" company: I don't know them, but I don't think they would lie just to make themselves give you a discount!
I mean like I said, they could have made the same video, showing you that everything is up to spec and basically tell you not to worry and demand that you pay the full price for the slightly swelling cells.
But no, they opted to give a discount just because we, the customers like to see flat cells. I think that says something about their reputability.
If I was in the market for buying these larger cells, I think these guys would be on my list...
Of course I could be entirely wrong about them. Maybe they are total frauds. But only God knows the true intentions of mankind. We can only judge by what is presented in front of us.
This is my judgment from the video...
P.S. You gotta love thier choice of wording "ultra thicker"... Sounds worse than it is... LOL.
At 2:36 she says the reason for cell bulging is slightly thicker jelly roll and that it's normal. I don't think so. This implies poor tolerance control during slurry coating process. Bulging cell makes it impossible to apply uniform clamping force across entire cell side when compressing them into a pack. These cells would never make it into EV or energy storage packs and should be priced as rejects. A reputable western company would reject these cells before even packaging them into aluminum containers. It looks like Chinese 2nd tier companies like EVE have much lower tolerance standards and that is probably the reason no western car company uses their cells. Even CATL is not safe judging by recent Mercedes EQS fires.
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And how many Western companies do you know that supply the whole world with their cells?
Everything has a price. If there were no Chinese manufacturers, many people in the world would still see these batteries only in pictures and not in their homes. Be more tolerant. I want to understand the nature of what happened.
ConnerLabs
Solar Enthusiast
Let’s see what the MB31 datasheet has to say on this:
There is a +-0.8mm tolerance, the caveat being that it’s measured at 300kg compression force. They don’t specify the thickness uncompressed at all.
In other words a brand new cell can be bulged to any extent, as long as the bulge is soft enough that 300kg would squish it back into shape.
They also expect the cell to expand up to 2.5mm over the course of its life. Preventing this expansion needs up to 6 metric tons of force.
The spring loaded DIY battery boxes that allow expansion while maintaining some compression force are actually a really good idea. 2.5mm per cell is 20mm for a stack of 8.
There is a +-0.8mm tolerance, the caveat being that it’s measured at 300kg compression force. They don’t specify the thickness uncompressed at all.
In other words a brand new cell can be bulged to any extent, as long as the bulge is soft enough that 300kg would squish it back into shape.
They also expect the cell to expand up to 2.5mm over the course of its life. Preventing this expansion needs up to 6 metric tons of force.
The spring loaded DIY battery boxes that allow expansion while maintaining some compression force are actually a really good idea. 2.5mm per cell is 20mm for a stack of 8.
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Quattrohead
Emperor Of Solar
Or one could assume they have bought a load of turds and are polishing them so that mugs will buy them.
Well, then it'll have to wait a little while. I'm getting my MB31 cells from Amy tomorrow. And in three years (or sooner, if things don't go according to plan) I will give you the cell capacity meters of your choice.
Wait for it!
Alkaline
Solar Wizard
Thanks its bs like this which makes my decision to go with rept cells all the better. V1/V2 280K also had this same bulging and they are loosing capacity rapidly even grade A after just 2-3 years.
Brucey
Velcro Man
Ironic we consider Eve to be premium but in China it's prob trash tier.
This is a f***ing joke (not the seller - EVE themselves). By doing this kind of bullshit they lost 99% credibility in my eyes.
It is absolutely clear what happened. They messed up a batch of cells and had them swell during QA testing. These cells will not have the same lifetime as non swollen cells. I carefully watched if these cells are heavier which would suggest they used too thick coating or some membrane at wrong thickness. Nope, they don't differ by more than a dozen grams. There is no thicker roll in there, it's a lie.
Their graphite electrode swelled for some reason. Either bad composition, some process error or an error during QA (not applying correct pressure during test charge, overcharge and not noticing etc).
These are not the same quality as the others. If my order that arrives in next 2 weeks turns up like this I'll be warranty-ing the hell out of it.
There is also a possibility they may say: the datasheet specifies 71.7mm+-0.8 under 300kg compression. But I highly doubt this will compress out. To me this looks like classic graphite swelling and probably at least 1mm per side in the center (She measured 0.5mm extra at the edge, so the center is very likely 2mm thicker). If this could just compress out they'd have used that as an argument. If it does compress out I could believe it is a thicker separator or some other part, but I seriously doubt so.
Which raises another big suspicion for me. Why is it that for years we had to make do with crappy rebadged B grade auto market reject cells from all suppliers and suddenly in the spring of this year we got the real deal for the very first time? Proper flat cells, with no signs of tampering on the QR codes? Why change now?
We all know previously all the cells that were making their way out of China were essentially grey market products that "fell off the truck" and they almost always were in hands of some shady characters before coming to the West that tried to rebadged them etc.
What changed? I have an idea what changed. EVE (or someone at the company) decided to not strike B on failing cells. They probably decided to bring a range of cells specifically for westerners that consist of cells that fail Chinese quality standard, but are not marked as such. Perhaps in the beginning they decided to keep the really crappy ones off the market to gain momentum... Now they want to cash in.
It is just a suspicion, but I think not far from truth. Prove me wrong anyone by showing me a visually good MB31 striken with a B on it! Show me one. If it exists, perhaps they are not all rebadged B grade cells... I hope I'm wrong as most of my system is using EVE cells.
As for "they will warranty these cells". Really? Do you believe any Chinese company will honor their warranty 3 years from now? We had a guy from Africa not long ago on the forum getting basically ignored by one of the "reputable" sellers after his cells swelled up and lost 20% charge after 2 years. (he has bms data to prove no abuse and another pack that is fine).
This is a pretty sad state of affairs.
It is absolutely clear what happened. They messed up a batch of cells and had them swell during QA testing. These cells will not have the same lifetime as non swollen cells. I carefully watched if these cells are heavier which would suggest they used too thick coating or some membrane at wrong thickness. Nope, they don't differ by more than a dozen grams. There is no thicker roll in there, it's a lie.
Their graphite electrode swelled for some reason. Either bad composition, some process error or an error during QA (not applying correct pressure during test charge, overcharge and not noticing etc).
These are not the same quality as the others. If my order that arrives in next 2 weeks turns up like this I'll be warranty-ing the hell out of it.
There is also a possibility they may say: the datasheet specifies 71.7mm+-0.8 under 300kg compression. But I highly doubt this will compress out. To me this looks like classic graphite swelling and probably at least 1mm per side in the center (She measured 0.5mm extra at the edge, so the center is very likely 2mm thicker). If this could just compress out they'd have used that as an argument. If it does compress out I could believe it is a thicker separator or some other part, but I seriously doubt so.
Which raises another big suspicion for me. Why is it that for years we had to make do with crappy rebadged B grade auto market reject cells from all suppliers and suddenly in the spring of this year we got the real deal for the very first time? Proper flat cells, with no signs of tampering on the QR codes? Why change now?
We all know previously all the cells that were making their way out of China were essentially grey market products that "fell off the truck" and they almost always were in hands of some shady characters before coming to the West that tried to rebadged them etc.
What changed? I have an idea what changed. EVE (or someone at the company) decided to not strike B on failing cells. They probably decided to bring a range of cells specifically for westerners that consist of cells that fail Chinese quality standard, but are not marked as such. Perhaps in the beginning they decided to keep the really crappy ones off the market to gain momentum... Now they want to cash in.
It is just a suspicion, but I think not far from truth. Prove me wrong anyone by showing me a visually good MB31 striken with a B on it! Show me one. If it exists, perhaps they are not all rebadged B grade cells... I hope I'm wrong as most of my system is using EVE cells.
As for "they will warranty these cells". Really? Do you believe any Chinese company will honor their warranty 3 years from now? We had a guy from Africa not long ago on the forum getting basically ignored by one of the "reputable" sellers after his cells swelled up and lost 20% charge after 2 years. (he has bms data to prove no abuse and another pack that is fine).
This is a pretty sad state of affairs.
If only they were available to me here in Europe without waiting 3 months to see if I'd been scammed.
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Good day, honored one!
You are categorically wrong. Instead of looking into it and understanding what went wrong, you went straight to pouring shit on the seller and EVE company. Be more impartial.
Do you realize how much cell production the company has? And you can't make such an eruption of filth over a single case? Come to your senses. God willing, your cells will be fine. As will my MB31s, which I'll receive tomorrow from the shipping company.
Perhaps it is due to the great electric vehicle sales disaster in recent year? The low demand for EV, sensationalised EV fire news and tariff don't help either. Not to mention not even China Chinese can afford to buy EV due to downturn in their economy.
littleharbor2
Solar Wizard
Just got done top balancing 16 MB31 cells. At this point all I can say is they all look flawless. No swelling whatsoever
Could you please tell me what current you charged the cells at top balance?
Did you charge without spring retraction or rigid retraction?
Cause I'm getting a 16 MB31 tomorrow too....
littleharbor2
Solar Wizard
10 amp bench power supply. No support at all. Charged to 3.6 vpc.
What a long time your upper ballance lasted!
littleharbor2
Solar Wizard
4 days
Suijkerbuijk
I cannot be held responsible for this information.
Wel today we have grade a+ .
So what is the difference?
Nobody knows and its just how the pack looks like ?
Funny thing we have with eggs today on my country.
White premium eggs .
Really its same chicken that set the eggs it just a new label .
So it can sell for more price in the store.
The world is beult on scams today just to have cash out of people pockets .
And even the state or country do the same .
Its to roll cash for the economy.
Please do enlighten me.... (seriously) What could've gone wrong during production that can both result in cells that are swollen in the center with no increase in weight that any manufacturer can say for sure has no impact on cell life.
We all know the typical reasons for cell swelling:
- graphite flaking/delamination.
- too much SEI growth
- gas formation due to electrolyte decomposition
- lithium plating
(often all 3/4 at the same)
What else is there that can cause cell swelling and not be detrimental to cell health and longevity? This is a genuine question. Where is @battery_professional when we need him
Whether it has any impact on performance we'll see once someone does a proper Dc IR test on them.
From watching for example this video:
You can see the cells used despite horrible swelling after being overcharged test with almost 100% capacity. He didn't take an AC IR reading. From experience I know it may very well have been only very slightly higher than the same cell before being destroyed. Also from experience I know DC IR (ability to provide high current without heating up) is the first function that goes to hell when cells are abused like this.
Don't believe me? See how his voltage drops when he applies what is only 0.3C for this cell. See 5:36. His cell is at 3.47 it drops below 3.12 (under 40A) and is still dropping under load. Let's be generous and say starting voltage is 3.45 (a fully charged cell) and it drops by 0.34V to 3.12V. That would be DC IR of 11.3mili ohm for a 100AH lifepo cell! This is almost an order of magnitude more than a healthy cell.
I do hope my cells are going to be fine, but I checked the date and the factory and my cells are made in the same factory around the same time (Jingmen, end of April 2024).
But it is not a single case, unless you mean a single customer that receives a container full of cells. 20% is like this and EVE tells them "naahh it's fine". Does this sound like a serious business? Yes, it is possible the whole thing is just one or two unscrupulous emoyees trying to offload rejected cells and the company itself is not behind this. There is only one way to tell. If EVE makes an official announcement to their sellers and customers to return these cells and apologises. If they don't, they are behind it.
I hope so too for both you and me. But I've done enough business with Chinese companies to always expect the worst.
We are talking about cells that arrive swollen from factory. Not about cells that swell later. This is a completely different thing. People may unknowingly overcharge, overpressure and so on, but when they arrive in a sealed box from the factory they absolutely must be perfectly flat.
Also I've already got 32 of these cells made in beginning of April and all are fine. Does this make me less worried? No, past performance is no guarantee of future one with Chinese companies.
Edit:
As for impact on longevity... I think in absence of real information to the contrary it is a reasonable assumption to treat them the same as any other QA failing (b grade) EVE cell. The fact the company marked it as fine is absolutely incredible to me. If they are truly fine show us your research EVE? Show us the dissection and microscope photos proving this is not graphite flaking, lithium plating and SEI growth. Explain it, then we can perhaps try to slowly rebuild trust lost.
Edit2: It is also possible Starmax got a batch of counterfeit cells and EVE is in the clear, we'll know soon if other people start getting these cells.
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