Tabless design cylindrical cells tests

Pajda said:
The EVE 4680 sample cell thing has been postponed indefinitely, but recently my colleague tuned up Micro-TIG and somehow the Cu busbar on aluminium is holding up. Cu with Al is not the best combination, but it will do for tests. The nominal capacity of the EVE 4680 sample is only 22Ah out of 26Ah declared, which cannot be seen as anything other than disappointing. Let's see how they cycle. A competitor in the EVE 4695 format has already completed 1000 cycle and hope I will update the table and graph soon
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Thank you for the update.
 
Very small update in the first post (updated graph with cycle life). EVE 4680 has started a life cycle. I hope to add pictures of the disassembled EVE40PL soon.
 
EVE in the available materials (I don't have specsheet) states charging voltage 4.20V for 4680 whereas for 4695 it is 4.25V, it is quite possible that the problem with nominal capacity lies here.

Added cycle life data for 4680, unfortunately I lost a batch of the first 50 cycles.
 
Thanks for sharing your results. I've sourced a batch of 40PLs for my own testing - primarily IR and thermals, although your testing already shows a pretty good advantage in the thermal department over even the P45B; Molicel seems to have gone tabless for the P50B which could close the gap.

Lishen, Tenpower, BAK are also all currently working on 4-5Ah tabless competitors, although Tenpower said they couldn't sample until EOY.

Out of curiosity, which equipment are you using for the 25C discharge test? And how's your experience with the ZKE A40L, is accuracy adequate for DCIR measurements?
 
ray88 said:
I don't really believe that but okay ..
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It is dissapointing though. It is only 226Wh/kg.

Unless it has huge power density or massive cycle life, it is actually quite dissapointing.

Something closer to 270-280Wh/kg and ideally 295-300Wh/kg.
 
BlueSwordM said:
It is dissapointing though. It is only 226Wh/kg.

Unless it has huge power density or massive cycle life, it is actually quite dissapointing.

Something closer to 270-280Wh/kg and ideally 295-300Wh/kg.
Click to expand...
From what I've seen, the Chinese manufacturers have been focusing on taller 46xx formats (maybe why it's not as packed as the 4695P). I don't think we'll see a lot of ~280Wh/kg+ 46xx until mid-2025.
 
That is definitely possible.

It seems like only Tesla and Gotion are keen on making large format HE cells currently.
 
thermal_runaway said:
Thanks for sharing your results. I've sourced a batch of 40PLs for my own testing - primarily IR and thermals, although your testing already shows a pretty good advantage in the thermal department over even the P45B; Molicel seems to have gone tabless for the P50B which could close the gap.

Lishen, Tenpower, BAK are also all currently working on 4-5Ah tabless competitors, although Tenpower said they couldn't sample until EOY.
Click to expand...
Glad to hear you were able to get samples of 40PL. Here you can see the Molicel P45B dual tab design.
P45B_cathode_tabs+terminal.jpg

Out of curiosity, which equipment are you using for the 25C discharge test? And how's your experience with the ZKE A40L, is accuracy adequate for DCIR measurements?
Click to expand...
I used a professional tester with a range of 100A per channel,that's normally available to me at my job. From my point of view, ZKE is a good choice for complete beginners in battery testers, because their software application allows you to learn the basic principles very quickly. On the other hand, this is also a disadvantage because the options for setting up the test are very limited. Since this spring I have finally managed to migrate from ZKE to the more advanced Neware BTS4000 system even for tests for the community.

ZKE testers are only able to perform single-stage DCIR tests. I haven't noticed a major problem with accuracy when compared with a professional tester, but it definitelly requires more work, because the DCIR value needs to be calculated from measured data using a macro, so it's a pretty thankless job.
 
BlueSwordM said:
It is dissapointing though. It is only 226Wh/kg.

Unless it has huge power density or massive cycle life, it is actually quite dissapointing.

Something closer to 270-280Wh/kg and ideally 295-300Wh/k
Click to expand...
As far as EVE4680 is concerned, Vapcell itself has already presented on its website graphs from its own measurements, which confirm a lower nominal capacity of ca 22-23 Ah in the range of 4.20-2.50 V (I still don't have the original specsheet from the manufacturer). Btw. My cycle life and table test results for 4680 are in the 4.20-2.80 V range, that explains the slightly lower capacity in my testes.

Further, if you look at the updated cycle life data of 4680 in the first post, you can see the "wave effect" that is typical for HE cells cycling at lower DoD, particularly with the charging voltage limitation. This is also suggested by the lower drop in capacity compared to the 4695.
Vapcell_4680.png
 
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Thanks for pic of P45B - super neat, probably easier to manufacture than 'tabless' for pretty decent results. P50B is sampling (I think Mooch has some), guessing based off 15mohm DCIR on specsheet they still haven't gone true 'tabless' yet.
Pajda said:
I used a professional tester with a range of 100A per channel,that's normally available to me at my job. From my point of view, ZKE is a good choice for complete beginners in battery testers, because their software application allows you to learn the basic principles very quickly. On the other hand, this is also a disadvantage because the options for setting up the test are very limited. Since this spring I have finally managed to migrate from ZKE to the more advanced Neware BTS4000 system even for tests for the community.

ZKE testers are only able to perform single-stage DCIR tests. I haven't noticed a major problem with accuracy when compared with a professional tester, but it definitelly requires more work, because the DCIR value needs to be calculated from measured data using a macro, so it's a pretty thankless job.
Click to expand...
Ahh, I see. Unfortunately don't have access to the Arbin from my last job... Good to know ZKE is decent, might get one for sample testing then. Our in-house tester currently is very similar, spits out a CSV w/ calculated internal resistance, and also it is not multichannel. I took a quick look at the Neware systems but maybe it is time to take a deeper dive, would definitely speed up impedance matching process.
 
This post shows why tabless cells are so very nice: hotspots are gone from tabs and you gain a very large amount of thermal conductivity from that large metal surface.

The endgame is full tabless using aluminium/copper conductors (copper for power density, aluminium for energy density), an ultra high conductivity electrolyte, a hard carbon + silicon thin film anode, active internal cell thermal management and full multi-channel electrolyte feeding channels .It wouldn't surprise me if we get 20C charging cells by 2026 at this rate.

The EVE 40PL and maybe Molicel P50 is the start of the HE-HP revolution, alongside CATL's and Gotion's new large format cells.
 
It might be worth mentioning the Ampace JP40.
It seems to sustain >30A continuous (around ~120W) and 45A pulses (around ~160W).
There is a JP50 in the pipeline according to this video published by the company on YouTube:
1719340339921.png

For information, Ampace is a joint-venture between CATL and ATL (CATL was spun off off ATL originally).
I am leaving this (sortof) specifications sheet here—the Ampace website is a bit hard to navigate:

Ampace 21700.png
 
Also relevant to the topic of tabless cylindrical cells. (Pajda, thanks again for it–certainly following your progress with enthusiasm.)

1. EVE 4695P has begun mass production, according to sources overseas.
2. Molicel P50B will go into "SOP"/Start of Production phase very likely in the coming months.
3. Molicel P60B in the 21700 format cylindrical has finished engineering validation.

One might say, good news overall.
 
riba2233 said:
you forgot Murata VX40 which looks better than the 40PL ;) although P50B will have probably better performance to capacity ratio.
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True, but the reason I'm not considering it much is that the 40PL is now widely available, unlike the Murata VX40 which seems to be OEM exclusive.
 
Souvlucky said:
3. Molicel P60B in the 21700 format cylindrical has finished engineering validation.

One might say, good news overall.
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I'm not sure if you've seen this but I found this photo on a forum in a language I don't understand. It was posted late last year though so the optimist in me wants to believe it because I didn't even see any P50B info back then. But of course this should be taken with a healthy grain of salt. No telling when it will actually be out thought!
 

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Here is in slightly better resolution the P45B / P50B / P60B comparison chart with tentative P60B specifications:

Molicel P60B.jpg
Though, technically, all listed cells are multi-tab (dual-tab specifically) rather than tabless.
Pajda's pictures above showcase this perfectly ;)
About tabless cells, here is the Lishen roadmap for cylindrical 21700 for 2023-2025:
Lishen 21700 tabless.png
 
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