Li-ion cells cycle ageing

Batteries, Chargers, and Battery Management Systems.
Shunt   100 mW

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Re: Li-ion cells cycle ageing

Post by Shunt » Dec 12 2019 2:09am

I'm a bit stunned how bad the panny/sanyos look .

docware   1 kW

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Re: Li-ion cells cycle ageing

Post by docware » Dec 12 2019 3:15am

Yes, M36 looks very nice, 29E is also good, especially DCIR. PF not so, on the other hand PF can serve lot of years for many people. This test confirms good 29E lifetime flippy always insisted, speak nothing of excelent LG M36 pajda each time highlighted.

It takes about 11 weeks to do 500 cycles. My intention is to finish testing at latest 700 cycles. I suppose for most of community will be 700 cycles data informative enough and testing another cells will be more interesting. Moreover, we haven´t enough time frame for long term testing.

Want to remind that this is „laboratory“ testing only, performed at specific testing conditions and stable temperature. Real battery pack conditions can differ significantly.

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Re: Li-ion cells cycle ageing

Post by Cephalotus » Dec 12 2019 5:22am

docware wrote:
Dec 12 2019 3:15am

It takes about 11 weeks to do 500 cycles. My intention is to finish testing at latest 700 cycles. I suppose for most of community will be 700 cycles data informative enough and testing another cells will be more interesting. Moreover, we haven´t enough time frame for long term testing.
It is your test, so obviously you are free to do what you want :-)

If you would like to get a broader audience a very long cyling test would be of high interst to solar home storage users, for which your cycling system with partial discharges at moderate C-rates does fit quite well.

Those are interested about cycling performance up to 5,000 equivalent full cyles (a solar battery system in Germany experiences around 250 equivalent full cycles per year and people hope that those will last up to 20 years)

We are talking about systems in the range of mostly 5kWh to 10kWh, so up to 1000 cells, so the interest in such testing would be of significant value.

Here is a DIY example with Panasonic PF cells:

https://www.photovoltaikforum.com/threa ... ost1457180

At least in Germany the solar home storage segment is already larger (in GWh battery capacity) than the e-bike segment. (but both marktes are dominated by commercial systems, not DIY)

john61ct   100 GW

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Re: Li-ion cells cycle ageing

Post by john61ct » Dec 12 2019 1:22pm

Silly IMO to use these chemistries for that application.

Lead, LFP or LTO only.

Shunt   100 mW

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Re: Li-ion cells cycle ageing

Post by Shunt » Dec 12 2019 7:16pm

Once christmas is in the books , I'm going to try to get the equipment to help with this testing. Notably 2C and 3C loads on M36 , 30Q, 29E, M29, VTC6, and Sanyo UR18650NSX up to around 300 cycles.

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Re: Li-ion cells cycle ageing

Post by Pajda » Dec 13 2019 6:11am

Shunt wrote:
Dec 12 2019 7:16pm
Once christmas is in the books , I'm going to try to get the equipment to help with this testing. Notably 2C and 3C loads on M36 , 30Q, 29E, M29, VTC6, and Sanyo UR18650NSX up to around 300 cycles.
This is highly appreciated. :) I just recommend to use the same equipment described by docware in the first post or better. For the beggining it is set of ZKETECH EBC-X0510 and BF-2A cell fixtures. Also at least 4 digit multimeter up to 10A for checking device calibration is mandatory. Try to avoid "modeler chargers".

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Re: Li-ion cells cycle ageing

Post by docware » Dec 22 2019 4:34am

Christmas package special delivery :) .
PF and GA 600 cycles, M36 550 cycles, 29E7 480 cycles, 30Q 189 cycles, MJ1 150 cycles. Comparative charts on capacity and DCIR added.
Panasonic PF 600 cycles.jpg
Panasonic PF 600 cycles.jpg (197.45 KiB) Viewed 2519 times
LG M36 550 cycles.jpg
LG M36 550 cycles.jpg (192.62 KiB) Viewed 2519 times
Sanyo GA 600 cycles.jpg
Sanyo GA 600 cycles.jpg (196.54 KiB) Viewed 2519 times
Samsung 29E7  480 cycles.jpg
Samsung 29E7 480 cycles.jpg (185.08 KiB) Viewed 2519 times
Samsung 30Q  189 cycles.jpg
Samsung 30Q 189 cycles.jpg (174.81 KiB) Viewed 2519 times
LG MJ1  150 cycles.jpg
LG MJ1 150 cycles.jpg (172.53 KiB) Viewed 2519 times
capacity comparative chart.jpg
capacity comparative chart.jpg (161.87 KiB) Viewed 2519 times
DCIR comparative chart.jpg
DCIR comparative chart.jpg (140.71 KiB) Viewed 2519 times

john61ct   100 GW

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Re: Li-ion cells cycle ageing

Post by john61ct » Dec 22 2019 6:40am

Wow that is an **incredibly** useful couple of charting formats!

I would like to propose, as a standard for how many cycles to cover:
however many is required to show 10% loss of capacity from new

more is always welcome but optional

500 cycles as the minimum
______
The 1A rate is fine, but to be more fair, what about using 0.5C for comparability across a wide range of cell capacity sizes?

so larger cells aren't artificially rewarded and smaller capacity models aren't penalized

Shunt   100 mW

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Re: Li-ion cells cycle ageing

Post by Shunt » Dec 22 2019 2:55pm

Freakin awesome Doc.

docware   1 kW

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Re: Li-ion cells cycle ageing

Post by docware » Dec 22 2019 4:15pm

john61ct wrote:
Dec 22 2019 6:40am

The 1A rate is fine, but to be more fair, what about using 0.5C for comparability across a wide range of cell capacity sizes?

so larger cells aren't artificially rewarded and smaller capacity models aren't penalized
I´ve been trying to choose such testing parameters that are close to real ebike conditions (charge, discharge, DOD), I mean ebike, not scooter or motorcycle. 500 cycles minimum, 700 cycles will be probably max.
Our task is not to be fair to the cells, our task is an effort to simulate real conditions. That´s why I use the same parameters for all cells, that´s why I don´t think in 1C, 0,5C, 0,3C category.

john61ct   100 GW

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Re: Li-ion cells cycle ageing

Post by john61ct » Dec 22 2019 7:15pm

Up to you of course

But what if 20Ah cells are used, new developments in future?

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Re: Li-ion cells cycle ageing

Post by flippy » Dec 22 2019 8:00pm

docware wrote:
Dec 22 2019 4:15pm
john61ct wrote:
Dec 22 2019 6:40am

The 1A rate is fine, but to be more fair, what about using 0.5C for comparability across a wide range of cell capacity sizes?

so larger cells aren't artificially rewarded and smaller capacity models aren't penalized
I´ve been trying to choose such testing parameters that are close to real ebike conditions (charge, discharge, DOD), I mean ebike, not scooter or motorcycle. 500 cycles minimum, 700 cycles will be probably max.
Our task is not to be fair to the cells, our task is an effort to simulate real conditions. That´s why I use the same parameters for all cells, that´s why I don´t think in 1C, 0,5C, 0,3C category.
i run my tests in 4 runs:

baseline (aka: verification of datasheet lifecycle),
max ratings (of datasheet),
actual expected use,
highest possible abuse the cell can see in that application.

that usually gives me a solid baseline for expected performance over time of the lifespan of the pack i am building.
Lithium beats liquid dinosaurs.

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Re: Li-ion cells cycle ageing

Post by takyka » Dec 24 2019 5:14pm

Docware,

When you decide to finish cycle testing, could you please make a full cycle test as per datasheet (for me at least on the PF )? Would be good to see if full capacity will have the same degradation than the voltage limited one...

Thank you for all your efforts doing these tests!

T.
T.

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Re: Li-ion cells cycle ageing

Post by john61ct » Dec 24 2019 5:26pm


flippy wrote:i run my tests in 4 runs:

baseline (aka: verification of datasheet lifecycle),
max ratings (of datasheet),
actual expected use,
highest possible abuse the cell can see in that application.

that usually gives me a solid baseline for expected performance over time of the lifespan of the pack i am building.
Sure, the more info the better when drilling down to the use-case-specific details on a particular battery.

But being able to quickly "scan compare" dozens of batteries for one simple factor requires a simplified apples-to-apples benchmark


docware   1 kW

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Re: Li-ion cells cycle ageing

Post by docware » Dec 24 2019 6:23pm

takyka wrote:
Dec 24 2019 5:14pm
Docware,
When you decide to finish cycle testing, could you please make a full cycle test as per datasheet (for me at least on the PF )? Would be good to see if full capacity will have the same degradation than the voltage limited one...
Thank you for all your efforts doing these tests!
T.
Yes, that is my intention. Only difference is that full cycle will not be at 0,2C but at 1 A for all cells, because i measured all cells full cycle capacity at 1 A before start of the test.
Here is example of GA comparison at the beginning (3 330 mAh) and after 611 cycles (3087 mAh) That is 92,7 % of initial capacity, which is better than 84,1 % at the cycling interval 4,1 – 3,4 V.
Sanyo GA 1A  4,2-2,5 V  3330 mAh,  3087 mAh after 611 cycles.jpg
Sanyo GA 1A 4,2-2,5 V 3330 mAh, 3087 mAh after 611 cycles.jpg (196.48 KiB) Viewed 2323 times

Shunt   100 mW

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Re: Li-ion cells cycle ageing

Post by Shunt » Dec 25 2019 12:58am

I could be mistaken, but I don't think many vendors in the states had the M36 , until very recently, but I just noticed that IMR has them for $3.49USD/ea . I can't wait to see how they do at 2C . Is there any chance one of you guys could run 100 cycles at 5 or 6 amps before I get my equipment ? Just so I know if it's even worthwhile to start them at that rate?

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Re: Li-ion cells cycle ageing

Post by docware » Dec 25 2019 3:45am

Shunt wrote:
Dec 25 2019 12:58am
M36 - I can't wait to see how they do at 2C . Is there any chance one of you guys could run 100 cycles at 5 or 6 amps before I get my equipment ? Just so I know if it's even worthwhile to start them at that rate?
No, there isn´t. By the way, MJ1 is probably better choice than M36 for such load.

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Re: Li-ion cells cycle ageing

Post by Honk » Jan 06 2020 12:34pm

docware wrote:
Dec 22 2019 4:34am
Christmas package special delivery :) .
PF and GA 600 cycles, M36 550 cycles, 29E7 480 cycles, 30Q 189 cycles, MJ1 150 cycles. Comparative charts on capacity and DCIR added.
Hi
Great charts and testing but something strikes me as odd.
When charged to 4.1V the cells should be approx 90% full, meaning e'g 29E should have about 2.6ah capacity available.
But the chart starts 2.2ah ???
Could you please explain this in case I have missed some test info!

Love this type of number crunching tests that reveal crucial data. Keep up the good work. :mrgreen:
Efficiency is king!

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Re: Li-ion cells cycle ageing

Post by Pajda » Jan 06 2020 2:42pm

Honk wrote:
Jan 06 2020 12:34pm
Hi
Great charts and testing but something strikes me as odd.
When charged to 4.1V the cells should be approx 90% full, meaning e'g 29E should have about 2.6ah capacity available.
But the chart starts 2.2ah ???
Could you please explain this in case I have missed some test info!

Love this type of number crunching tests that reveal crucial data. Keep up the good work. :mrgreen:
In short: docware`s data are correct.

29E cell have declared typical capacity of 2.85Ah and minimum capacity of 2.75Ah, so you can count with ca 2.8Ah for a new cell. Typical capacity is measured at 100% DoD (4.2-2.5V), with 0.2C discharge rate and 50mA charging cut-off current. You are right that charged at 4.1V you will get ca 90% of typicial capacity = ca 2.5Ah at 0.2C discharge rate down to 2.5V! But docware is using narrower SoC window 4.1-3.3V which cost another significant amount of energy, particularly if you discharge at higher C rates. docware is using ca 0.9C discharge rate, not 0.2C used for typical capacity.

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Re: Li-ion cells cycle ageing

Post by leffex » Jan 06 2020 3:11pm

docware wrote:
Dec 22 2019 4:15pm
.
Nice charts I love them! Thanks alot for it!

MJ1 so cool new cell that give you epic and long performance life.

I'm stuck with my used PFs but it could be worse if I had used my used and old Sony V3 10A capable in my latest battery build, cells who have degraded down to only 1800-2100mah which when new had 2150mah.

EDIT: just found this on random photo search by accident!
https://chargedevs.com/newswire/tesla-b ... new-paper/
Salestech in an ebike store

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Re: Li-ion cells cycle ageing

Post by Honk » Jan 06 2020 3:24pm

Pajda wrote:
Jan 06 2020 2:42pm
In short: docware`s data are correct.
Hi Pajda and thank's for the clarification.
I suspected this was the case but it's better to ask than being uncertain.

So far LG M36 looks like the new killer cell stealing the crown in terms of cycle ageing properties.
Efficiency is king!

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Re: Li-ion cells cycle ageing

Post by docware » Jan 06 2020 4:20pm

I believe Pajda´s explanation is sufficient. Bellow is 29E7 No5 full capacity measured before cycling test. Initial 2 200 mAh at the start of cycling is 78,8 % of full capacity.
As the latest long life cell from Jeff Dahn´s team will not be available to us early, M36 seems to be really good choice for some time. 8)
Samsung 29E7 No5 4,2 - 2,5 V  1A  2A  3A.jpg
Samsung 29E7 No5 4,2 - 2,5 V 1A 2A 3A.jpg (198.49 KiB) Viewed 1951 times

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Re: Li-ion cells cycle ageing

Post by richie241 » Jan 12 2020 1:16pm

Cephalotus wrote:
Dec 12 2019 5:22am
docware wrote:
Dec 12 2019 3:15am

It takes about 11 weeks to do 500 cycles. My intention is to finish testing at latest 700 cycles. I suppose for most of community will be 700 cycles data informative enough and testing another cells will be more interesting. Moreover, we haven´t enough time frame for long term testing.
It is your test, so obviously you are free to do what you want :-)

If you would like to get a broader audience a very long cyling test would be of high interst to solar home storage users, for which your cycling system with partial discharges at moderate C-rates does fit quite well.

Those are interested about cycling performance up to 5,000 equivalent full cyles (a solar battery system in Germany experiences around 250 equivalent full cycles per year and people hope that those will last up to 20 years)

We are talking about systems in the range of mostly 5kWh to 10kWh, so up to 1000 cells, so the interest in such testing would be of significant value.

Here is a DIY example with Panasonic PF cells:

https://www.photovoltaikforum.com/threa ... ost1457180

At least in Germany the solar home storage segment is already larger (in GWh battery capacity) than the e-bike segment. (but both marktes are dominated by commercial systems, not DIY)

Hi all,

@docware
Thank you a lot for your tests and please keep going. :bigthumb:

I build a Powerwall from LG M36 (14S60P - x2 is comming) and you cycle data is exactly what i was looking for.
Max. charge / discharge is 500mA, later round about 400mA. Im afraid how the cells and cyclelife performs.
Like Cephalotus said :D

The datasheet says that the cells have 80% cap after 1000 cycles - your test locks better until now.

BR
Richie
nyhsvi2.jpg
nyhsvi2.jpg (298.81 KiB) Viewed 1754 times

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Re: Li-ion cells cycle ageing

Post by eMark » Jan 14 2020 9:32am

The Samsung 29E seems to be Pajda's favorite; while the Samsung 30Q is almost derided by Pajda for its shorter cycle life (and calendar aging) when used for power tools despite its good-looking DCIR so far. Is one reason the 30Q is frowned upon as coming up short for cycle life longevity based on its use in power tools (and vaping) more than mild-mannered ebiking where the current draw requirement may only be 5 amps?

Panasonic's 21700 (Tesla Gigafactory NCA chemistry) production is still lagging behind demand. It's rumored that Tesla is also using Samsung 21700 (high capacity cells) to keep up with production demands. Apparently Tesla likes the Li-NiMnCoO2 chemistry so much for all around performance that Tesla may eventually break ties with Panasonic's LCA 21700 cells. It's nothing new that LNM 8-1-1 chemistry is giving NCA lithium chemistry a run for the money. Is it possible that the Samsung 30Q (LNM) actually has decent-to-good cycle life longevity when it's ebiking application isn't for raw performance like that of power tools and vaping?

The current thinking by Padja seems to be that 2900mAh class lithium cells have an ebiking advantage. And yet the Samsung 30Q is only 100mAh higher with its 3000mAh capacity, its 15A rating and its lower DCIR than any other cell being tested by docware (so far). The days of 29E being a darling may be a thing of the past as time marches on with on-going lithium chemisty research, innovation and improved quality control.

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Re: Li-ion cells cycle ageing

Post by docware » Jan 18 2020 6:22am

New data for new year 2020.
All cells were resting at 3,5 V / 15 °C for 2 weeks during Christmas because the table was occupied by Christmas tree. Thanks to this pause we can see some partly capacity recovery of 29E7 and GA. Capacity degradation would be probably slower in real life for these two cells.
PF and GA 700 cycles, M36 633 cycles, 29E7 560 cycles, Samsung 30Q 270 cycles, LG MJ1 235 cycles.
Panasonic PF 700 cycles.jpg
Panasonic PF 700 cycles.jpg (205.23 KiB) Viewed 1406 times
LG M36   633 cycles.jpg
LG M36 633 cycles.jpg (201.15 KiB) Viewed 1406 times
Sanyo GA  700 cycles b.jpg
Sanyo GA 700 cycles b.jpg (149.25 KiB) Viewed 1406 times
Samsung 29E7  560 cycles b.jpg
Samsung 29E7 560 cycles b.jpg (176.35 KiB) Viewed 1406 times
Samsung 30Q  270 cycles.jpg
Samsung 30Q 270 cycles.jpg (176.47 KiB) Viewed 1406 times
LG MJ1 235 cycles.jpg
LG MJ1 235 cycles.jpg (174.43 KiB) Viewed 1406 times
Capacity decay comparison.jpg
Capacity decay comparison.jpg (165.77 KiB) Viewed 1406 times
DCIR rise comparison.jpg
DCIR rise comparison.jpg (150.15 KiB) Viewed 1406 times

Panasonic PF and Sanyo GA reached 700 cycles and their testing has been finished (apologize to Cephalotus, richie241 and other solar home storage users :) ).

Panasonic PF after 700 cycles has 79,4 % of initial capacity in cycling interval 4,1 – 3,3 V at 2,5 A. Measuring in standard interval 4,2 – 2,5 V at 1 A shows 88,6 % of initial capacity and 87,6 % of initial energy.
Panasonic PF No2 1A initial versus 700 cycles comparison b.jpg
Panasonic PF No2 1A initial versus 700 cycles comparison b.jpg (184.37 KiB) Viewed 1406 times

Sanyo GA after 700 cycles has 83,8 % of initial capacity in cycling interval 4,1 – 3,4 V at 2,5 A.
Measuring in standard interval 4,2 – 2,5 V at 1 A shows 91,4 % of initial capacity and 91,4 % of initial energy.
Sanyo GA 1A after 700 cycles comparison.jpg
Sanyo GA 1A after 700 cycles comparison.jpg (223.36 KiB) Viewed 1406 times

Following picture displays cell surface temperature during cycling.

Panasonic PF No2 cycling - temperatures.jpg
Panasonic PF No2 cycling - temperatures.jpg (134.39 KiB) Viewed 1406 times
temperature measurement.jpg
temperature measurement.jpg (111.03 KiB) Viewed 1406 times
Last edited by docware on Jan 18 2020 9:49am, edited 1 time in total.

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