Tabless design cylindrical cells tests

Ok so yes, they are from the new 18V+ pack and bosch heavily markets them as tabless, you can see their material here:

Bosch is Launching their First 18V Tabless Cordless Power Tool Battery

toolguyd.com toolguyd.com

Regarding timeline they have been announcing this pack for over a year but just started shipping recently, so cells could be a bit older (unless they delayed the pack because they were waiting for them).

I have already asked about sending them to you, I hope they will agree, it would be awesome! I also have to ask if they can open them, I think they could but we'll see.

Now regarding molicel and announcements.. IDK what to think anymore, they did announce a lot of stuff, nothing around 4ah though (except for XA3 which should perform much much better than these), but there is also Murata who never talk and don't want to admit that they make VX40 cells so idk if they have some confidentiality agreement with Bosch, really not sure lol.
 
riba2233 said:
...but there is also Murata who never talk and don't want to admit that they make VX40 cells so idk if they have some confidentiality agreement with Bosch, really not sure lol.
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Thanks!
IMO it‘s not Murata as they’ve never used can laser etching and that can looks exactly lile a Moli. It wouldn‘t be the first time an error or delayed shipment led to different cells being used in a product (than what was claimed). Other less terrible possibilities too, of course.
 
CamLight said:
Thank for posting those photos! Wow, yea, those look like P42A’s.

IMO Moli wouldn‘t keep their first tabless cell ever from being announced. They have announced the P60B, P70X, P22S, P30S, P50S, XA1, XA2, and XA3 and they could still only sell those to a single customer for a year or two. Moli marketing I think would demand that they can go public with info about their first tabless cell, if it existed, so folks would stop thinking Moli was lagging in new tech development.
Click to expand...

Based on Molicel parent company financial reports the XA1, XA2, and XA3 are all tabless cells. They are currently in production validation stage.
 
New tabless cell article incoming:

Of course, many of the authors are scientists/engineers working for Lishen, so take a lot of the stuff with a grain of salt.
However, while the article is decent, the accompanying material is what you peeps actually want :)

It's always nice to be able to look at a full teardown and methodology.
I'm surprised Lishen are only getting 280Wh/kg out of an NMC935 cell and with a 14% Si loaded graphite anode and tabless interconnects.

Their packaging optimizations in other areas clearly needs some work :)
 
So a tabless cell jelly roll's anode and cathode is not spot welded like tabbed cells, which allows more contact area to the current collectors/ outside terminals? W/o spot welding, how well does the butt joint contacts hold up over time and use?

Sorry if that's a dumb question.
 
BlueSwordM said:
New tabless cell article incoming:

Of course, many of the authors are scientists/engineers working for Lishen, so take a lot of the stuff with a grain of salt.
However, while the article is decent, the accompanying material is what you peeps actually want :)

It's always nice to be able to look at a full teardown and methodology.
I'm surprised Lishen are only getting 280Wh/kg out of an NMC935 cell and with a 14% Si loaded graphite anode and tabless interconnects.

Their packaging optimizations in other areas clearly needs some work :)
Click to expand...
Cycle life looks very good though, I guess they optimised the design for it.
 
BlueSwordM said:
I'm surprised Lishen are only getting 280Wh/kg out of an NMC935 cell and with a 14% Si loaded graphite anode and tabless interconnects.
Click to expand...
IMO we’re spoiled by the lab and A-Sample pouch energy density numbers for cells with a much shorter cycle life. For a commercially available NMC round cell with good cycle life that 280Wh/kg is fantastic. Even with a Si+Gr anode.
 
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Zambam said:
So a tabless cell jelly roll's anode and cathode is not spot welded like tabbed cells, which allows more contact area to the current collectors/ outside terminals? W/o spot welding, how well does the butt joint contacts hold up over time and use?
Click to expand...
Correct.
I haven’t seen even a reference to that being a potential aging mechanism for true tabless cells so I’m assuming it’s not an issue.

The ”tabless“ 18650’s and 21700’s all have a single tab between the top current collector and the top contact though. And the BAK 45D even has single tab from the bottom current collector to the can. That’s not an aging issue either, just a remark about “tabless” cells often not being a true tabless design.
 
CamLight said:
IMO we’re spoiled by the lab and A-Sample pouch energy density numbers for cells with a much shorter cycle life. For a commercially available NMC round cell with good cycle life that 280Wh/kg is fantastic. Even with a Si+Gr anode.
Click to expand...
No no, I just expected closer to 300-310Wh/kg.

They'll likely gain a lot from shaving down the cell can and the inefficient current collector design since it's eerily close to the 1st Gen Tesla 4680 design; the 1st gen 4680 cell design had very inefficient packaging.
 
CamLight said:
Correct.
I haven’t seen even a reference to that being a potential aging mechanism for true tabless cells so I’m assuming it’s not an issue.

The ”tabless“ 18650’s and 21700’s all have a single tab between the top current collector and the top contact though. And the BAK 45D even has single tab from the bottom current collector to the can. That’s not an aging issue either, just a remark about “tabless” cells often not being a true tabless design.
Click to expand...
Pic is from link to article posted by riba2233 above. Are the 2 current collector disks made to work like a spring to maintain good electrical contact to the aluminum and copper jelly roll foil, since neither aluminum or copper is springy?

Screenshot 2025-01-11 at 3.53.38 PM.png
 
Zambam said:
Pic is from link to article posted by riba2233 above. Are the 2 current collector disks made to work like a spring to maintain good electrical contact to the aluminum and copper jelly roll foil, since neither aluminum or copper is springy?
Click to expand...
I don’t remember the details of the current collector plates ( but they’re also Cu and Al) for the larger cylindrical cells but if they’re anything like the smaller cells there’s no dependency on springiness, I’m sure partially for the reason you brought up. The internals of the cell are just pressed together tightly or laser welded.

These companies have spent millions of dollars and years developing these cells and just aren’t going take chances like using springs or other low reliability construction/design. Especially since they’re typically designed for EV use where they will experience literally millions of shocks over their life.
 
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Zambam said:
Pic is from link to article posted by riba2233 above. Are the 2 current collector disks made to work like a spring to maintain good electrical contact to the aluminum and copper jelly roll foil, since neither aluminum or copper is springy?
Click to expand...
If you take a look at Pajda's teardowns (page 1) they all use laser welding for current collector connections (to both jelly roll and can).
 
I see no technical reason why the tabless design could not be used for LFP cylindrical cells as well. The fact that they are almost non-existent on the market is in my opinion due to commercial reasons. The point is that the cylindrical format in the last decade has got strong competition in the pouch format (which has almost displaced it from consumer electronics). So outside of automotive and eVTOL, cylindrical format has its main market in power tools and light electric vehicles, which always needs the highest possible energy density combined with high mechanical robustness on the cell level. LFP still cannot deliver the desired level of energy density.

And as for automotive, you may have heard that the CEO of CATL laughed at Tesla for their 4680 format. The point is that the battery in a BEV is not really as demanding application as for example above mentioned power tools, and so cylindrical format offers no significant advantage over pouches or prismatic here. So CATL as a supplier of LFP technology to Tesla can easily meet the requirements with prismatic format which is now the most comfortable for production for them.
 
Zambam said:
Can you provide links to articles on that? Thx
Click to expand...
Original article: https://www.reuters.com/business/au...build-us-plant-if-trump-allows-it-2024-11-13/

But Zeng said he had told Musk directly that his bet on a cylindrical battery, known as the 4680, "is going to fail and never be successful."
"We had a very big debate, and I showed him," Zeng said. "He was silent. He doesn't know how to make a battery. It's about electrochemistry. He's good for the chips, the software, the hardware, the mechanical things." Musk and Tesla did not immediately respond to a request for comment on Tuesday.
Click to expand...
 
BlueSwordM said:
Apparently, yes:
lib.energy

Tabless Lithium Cells: 26650 & 21700 with Next-Gen Power

Explore the future of battery tech with our Tabless Lithium Cells. Our 26650 and 21700 models offer unmatched power density and safety.
lib.energy lib.energy

I remember seeing this a while back, and being surprised it even existed.
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I should note that Lib appears to be just a reseller... they don't disclose this clearly -- their 21700 spec is exactly the same as the BAK INR21700-45B and their testing sheets are the same format as the ones I've received from BAK directly.

I don't see a 26650 on this list, would be interesting to figure out who's the actual manufacturer for those LFPs.
 
That was quite blunt by Zeng. Wonder how it was received? With his wealth and power, I'd think Musk would want to prove Zeng wrong. So how is Tesla's 4680 cells coming along?
 
Zambam said:
That was quite blunt by Zeng. Wonder how it was received? With his wealth and power, I'd think Musk would want to prove Zeng wrong. So how is Tesla's 4680 cells coming along?
Click to expand...
There's been some neat advancements -- fully dry cathode/anode cell -- but a lot of growing pains. I think only recently have they been able to push and scale their program. I've heard that the 4680 Model Ys had a lot of issues including poor charging behavior, and some rumors of the same happening on Cybertruck.

It should be noted that there's no shortage of industry demand for 46xx.. aside from Tesla: LG, Samsung, Panosonic, EVE, BAK, SVolt, Gotion, Northvolt, Kumyang + many others are ALL pursuing 46xx cells for production. Rivian, BMW, Rimac are all shifting to it for use in their vehicles. Based on my experience there's certainly benefits vs. 21700 if you've got a lot of experience built up in cylindrical manufacturing/design engineering -- bottleneck for a lot of companies right now is 46xx production is not fully ramped (constantly delays on production promises), especially non-CN production (tariffs!).
 
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