CATL 271ah, EVE 280ah or Lishen 272???

[Michael B Caro]

My supplier with your choice of M6 or M8 studs at no extra charge not only has Lishen 272ah,but also:
Lishen 202ah
Catl 202ah with QR code
Catl 271ah with QR code
and 310ah without QR code

 

[Just John]

For the Lishen would it be best to order and install the lugs yourself to avoid any shipping damage.

Assuming you have a laser welding machine set up? I don't.

 

[blutow]

I assume the studs are aluminum if they are welding them onto the terminals? I don't know anything about batttery cell manufacturing, but I'm pretty sure you can't weld aluminum and steel together. Alumimum studs should be good (and probably bring a little improved conductivity), but you still need to be careful since they are much softer than stainless. I've got some 272 lishen's on the way with M6 bolts and I plan to put my own studs in. I certainly would have done the M8 welded stud option if it had been available at the time.

 

[Pidjey]

I think studs are normally stainless steel. As far as I know their only function is mechanical.

 

[blutow]

I think studs are normally stainless steel. As far as I know their only function is mechanical.

Agree for screw in studs, but I'm seeing these described as welded studs. I'm pretty sure there is no way to weld stainless studs to aluminum terminals, but I could be wrong on that.

 

[Just John]

Agree for screw in studs, but I'm seeing these described as welded studs. I'm pretty sure there is no way to weld stainless studs to aluminum terminals, but I could be wrong on that.

I will be interested in seeing the results.
Can I Weld Aluminum to Steel?

 

[lexio]

Agree for screw in studs, but I'm seeing these described as welded studs. I'm pretty sure there is no way to weld stainless studs to aluminum terminals, but I could be wrong on that.

explosive welding will do it but the results can vary

but on the serious side aluminum and stainless steel is waiting for corrosion big way (build alu yachts )

 

[timeforagorism]

I put in an order for the 272AH with 'attached lugs'. I called it welded in the communication so maybe that language just stuck in their response. I guess we shall see when the order comes. I ordered 20, hoping to build two solid 8S packs and one 4S pack with the odd ball cells.

So for building these packs so far:

• Box building
  • It seems like there is some conductivity questions/answers about the casing on the cells. It sounds like the solution is to put some non-conductive material between the cells as well as other sides. It seems a couple mil piece of plastic could do this. I am planning on building a wooden box for now.
• Compressing the cells
  • I am not sure how this would be measured, or would one just make a 'snug' box for them. I like the idea in one thread about plywood ends then rods on each corner. It seems like there would be some torque we could come up with for that.
• Bus bars
  • For low C applications it seems like the provided ones may be okay.

 

[Michael B Caro]

Agree for screw in studs, but I'm seeing these described as welded studs. I'm pretty sure there is no way to weld stainless studs to aluminum terminals, but I could be wrong on that.

The information I have is that they are in fact welded, and that comes from multiple suppliers and a couple of manufacturers.
I will try to get clarification of the metals involved and the welding process they use when they come into work tonight.

 

[lexio]

I put in an order for the 272AH with 'attached lugs'. I called it welded in the communication so maybe that language just stuck in their response. I guess we shall see when the order comes. I ordered 20, hoping to build two solid 8S packs and one 4S pack with the odd ball cells.

So for building these packs so far:

• Box building
  • It seems like there is some conductivity questions/answers about the casing on the cells. It sounds like the solution is to put some non-conductive material between the cells as well as other sides. It seems a couple mil piece of plastic could do this. I am planning on building a wooden box for now.
• Compressing the cells
  • I am not sure how this would be measured, or would one just make a 'snug' box for them. I like the idea in one thread about plywood ends then rods on each corner. It seems like there would be some torque we could come up with for that.
• Bus bars
  • For low C applications it seems like the provided ones may be okay.

send them a picture of the lugs you want to avoid miscommunication
ha cell compression or not: this is my take on it take the cell with + insulation is the max distance for your box
this is what i need to make.
in the bottom and the top slot there will be a pice of wood witch have the total distance of the cell+ isolation

 

[Michael B Caro]

Welded stud

 

[Gazoo]

Welded stud

Is that a Lishen cell? Can you post a higher resolution photo? None of the terminals surface area is usable and busbars may not be a good idea. I am not so sure there is enough surface area on the flange for large lugs either. Also stainless steel is not a very good conductor. Not an expert in this area so I am just throwing it out. But I think it would be better for one to get the cells without the welded studs and use grub screws and a thread locker. And use a torque of no more than 4.5nm when tightening the nuts on the busbars.

I believe the suppliers use laser welding. That's what bullion told me when I was going to purchase the 202ah Lishen's from them. The Lishen 202ah cells have a large square terminal on them so it's not as much of a concern since the supplier can laser weld a square pad with stud to the large square terminal.

 

[Michael B Caro]

Not sure if the fuzzy pic is of a Lishen cell or a CATL cell, but they are the same terminal.
This is not a 272ah cell, but it is the same shape terminal with the stud welded on.
As for the rest. I will discuss it with the supplier that does these all the time when they get into work tonight.

 

[Gazoo]

If I was buying them I would be concerned about the surface area of the flange. It doesn't matter to me if they do it all the time or not....lol.

It's my own observation and might not be anything to be concerned about. Since having studs welded is an option the buyers can decide. Thanks.

 

[Michael B Caro]

If I was buying them I would be concerned about the surface area of the flange. It doesn't matter to me if they do it all the time or not....lol.

It's my own observation and might not be anything to be concerned about. Since having studs welded is an option the buyers can decide. Thanks.

True, but I get a lot of new members asking me questions, and I want to make sure that when I make a recommendation it is based on the best information I can get. You know me well enough to know that the technical aspects are not my strength, and so I depend on information gleaned from others and I am constantly trying to learn more.

 

[timeforagorism]

If I was buying them I would be concerned about the surface area of the flange. It doesn't matter to me if they do it all the time or not....lol.

It's my own observation and might not be anything to be concerned about. Since having studs welded is an option the buyers can decide. Thanks.

I assume the concern is there won't be enough surface area when pulling large loads? If someone was going to run these at like 100 amp max would your concerns be less?

 

[AussieSim]

Welded stud

I posted this in another thread. I would hope that the laser welding results are as follows

 

[Michael B Caro]

Is that a Lishen cell? Can you post a higher resolution photo? None of the terminals surface area is usable and busbars may not be a good idea. I am not so sure there is enough surface area on the flange for large lugs either. Also stainless steel is not a very good conductor. Not an expert in this area so I am just throwing it out. But I think it would be better for one to get the cells without the welded studs and use grub screws and a thread locker. And use a torque of no more than 4.5nm when tightening the nuts on the busbars.

I believe the suppliers use laser welding. That's what bullion told me when I was going to purchase the 202ah Lishen's from them. The Lishen 202ah cells have a large square terminal on them so it's not as much of a concern since the supplier can laser weld a square pad with stud to the large square terminal.

Here is the string of responses to your concerns:

"once the hole is broken. they can do nothing with the cells. that's why I do more screw pin.
this is screw pin customized for prismatic cell. and welded with high power laser.
it's aluminum alloy M6 base and alloy steel screw pin. we have both M6 and M8 for choice.
the M6 base is same as the cell surface area. and M8 is a little bigger than the cell.
Lishen 202 have new version and old style. the old version is big square terminal. new version is round like catl."

And of course the Lishen 272 is the round style like catl.
So, it appears as though I was incorrect when I was guess that they were getting cells with no hole or stud and then welding the stud on. That was my guess after having seen factory options of welding a stud on where there was no hole, or actually welding bus bars to cells to connect them starting with cells that had no hole or stud.
Instead, from what I can glean from what he said, it is a screw that has a stud. They screw it into the cell and then laser weld it in place.

 

[Gazoo]

I am not sure what they mean by "once the hole is broken" unless they mean once a hole is drilled into the terminal. And once a hole is drilled into the terminal it can be tapped. But they say once the hole is broken they can do nothing more with the cell except laser weld a stud?

It's my understanding a screw pin is a pin with threads. Think of a screw with half of the threads missing for example. They are saying the base is the same size as the terminal. But as far as I can tell, referencing the photos you posted, the top of the base is not the same size as the cell terminal.

It's also confusing they say the M6 base is made out of aluminum, and the pin is made out of some kind of steel. I could understand this if they are using an aluminum base and a steel screw pin. If they are using a steel screw pin, then how are they welding the base to the screw pin? Maybe the whole assembly comes with the steel screw pin already mounted to the aluminum base.

Very confusing to me. However if they are indeed using an aluminum base then that is reassuring.

Instead, from what I can glean from what he said, it is a screw that has a stud. They screw it into the cell and then laser weld it in place.

No I don't think it's that simple.

They mention screw pin and also say "the M6 base is same as the cell surface area. and M8 is a little bigger than the cell."

They are using some kind of base and I can see it in all of the photos you posted.

 

[Michael B Caro]

"Maybe the whole assembly comes with the steel screw pin already mounted to the aluminum base."
This is what I was trying to describe. Something specially designed and made to screw down into the M6 poll that has a stud on the other end but they do not rely on just screwing it in but laser weld it too..... I think.

 

[Gazoo]

Yeah, I am not experienced at all in the area of laser welding. And I don't know if the reduced surface area for mounting busbars or lugs will matter regarding current carrying capacity, although it is reduced quite a bit on account of the type of base they are using. I do think people need to be aware of this. Personally I don't know which way I would go. I guess we have to trust the suppliers know what they are doing. I know how difficult it can be to communicate with them due to the back and forth translations. Everyone needs to make their own decisions deciding on studs or screws.

 

[Surferdudemi]

I am not sure what they mean by "once the hole is broken" unless they mean once a hole is drilled into the terminal. And once a hole is drilled into the terminal it can be tapped. But they say once the hole is broken they can do nothing more with the cell except laser weld a stud?

It's my understanding a screw pin is a pin with threads. Think of a screw with half of the threads missing for example. They are saying the base is the same size as the terminal. But as far as I can tell, referencing the photos you posted, the top of the base is not the same size as the cell terminal.

It's also confusing they say the M6 base is made out of aluminum, and the pin is made out of some kind of steel. I could understand this if they are using an aluminum base and a steel screw pin. If they are using a steel screw pin, then how are they welding the base to the screw pin? Maybe the whole assembly comes with the steel screw pin already mounted to the aluminum base.

Very confusing to me. However if they are indeed using an aluminum base then that is reassuring.


No I don't think it's that simple.

They mention screw pin and also say "the M6 base is same as the cell surface area. and M8 is a little bigger than the cell."

They are using some kind of base and I can see it in all of the photos you posted.

I think "hole is broken" means you've stripped the threads. Remember that you're translating from Chinese and there's not always a direct translation to English idioms.

"Screw pin" = stud, I think

For M8, perhaps the stud is M6 to screw into the terminal and M8 for the upper half?

 

[Gazoo]

I think "hole is broken" means you've stripped the threads. Remember that you're translating from Chinese and there's not always a direct translation to English idioms.

"Screw pin" = stud, I think

For M8, perhaps the stud is M6 to screw into the terminal and M8 for the upper half?

That makes sense. But with either an M6 or M8 stud it's clear they are using a base. I think flange would be a better word to describe it? I am going by the photos posted.

 

[fission]

This video shows an example of a round stud before being welded on:

I am curious if anyone else has input on or experience with these welded on studs. Amy at Luyuan said they are starting to offer this service and I am considering it for the EVE LF105 cells due to concern over the m4 threading. She said they haven't laser welded the 105's yet so I would be a guinea pig.

An internal resistance test through the welded connection compared to a normal IR test would be nice to see. I will try to make that happen when they get the new cells in. She is going to send pictures of their studs to me when available.

*Sorry if this is a hijack, I can post this as a separate thread.

 

[Michael B Caro]

This video shows what round studs look like before being welded on:

View attachment 32797

I am curious if anyone else has input on or experience with these welded on studs. Amy at Luyuan said they are starting to offer this service and I am considering it for the EVE LF105 cells due to concern over the m4 threading. She said they haven't laser welded the 105's yet so I would be a guinea pig.

An internal resistance test through the welded connection compared to a normal IR test would be nice to see. I will try to make that happen when they get the new cells in. She is going to send pictures of their studs to me when available.

The supplier that I have that deals in a LOT of cells with studs, says they have a specially designed "screw pin" for adding the studs to the cells.
My understanding is that this "screw pin" has a screw coming out of the opposite side from where the stud is. It is screwed down into the threaded hole of the M6 poll and then laser welded.

I will try to confirm that 100% tonight and also see I can get a picture of said "screw pin" to be sure.