Nissan Leaf Cells Test Data

[agniusm]

Updating with some info. For someone who uses modules in its original configuration. You can fit 6 modules in a space of 5 by taking off aluminium enclosures/cans. By doing so you don't need steel spacers anymore and by scraping all those parts you only gain 1kg by adding another module. You also scrap all the blue insulator plastic sheets except the outer ones. The thickness of 6 mudules works out at roughly 174mm. For securing modules you will need 9mm diameter aluminium bars threaded on both ends and countersunk bolts.

Dont forget to put some fishpaper in between the modules so you could take it apart later.

 

[Nuts&Volts]

I read somewhere in another thread that the 2015 Leaf cells may have a higher C-rating. Can anyone confirm this? I know that they have a tweaked chemistry of some kind to handle hot temperatures better and improve warm weather cycle life.

 

[Hillhater]

C ratings are always debatable , depending on the test procedure and the limiting parameters.
The original Leaf cells were rated at 3-5 C, but some independent tests suggest it could be as high as 10C or more, depending on the amount of voltage sag , capacity reduction, cycle life, etc you are prepared to accept.

 

[Warren]

They tweaked the chemistry back in 2013. The modules look a bit different. The aluminum cover is made of two identical halves, with a gap between them, not the closed sardine can of the earlier modules.

 

[Arlo1]

I think the 10c rated leaf cells started rolling out in the late 2014 models or the 2015 models.
The older stuff was 3c rated.

 

[Nuts&Volts]

I think the 10c rated leaf cells started rolling out in the late 2014 models or the 2015 models.
The older stuff was 3c rated.

Ok thanks guys. I have some 2012 modules. They only hold about 55-56Ah in them, but I'm able to pull 640A at peak out of them. So I call that about 10-11C. Eventually when I have to upgrade this pack I want to be sure I can get a bit more power from them.

 

[Hillhater]

I think the 10c rated leaf cells started rolling out in the late 2014 models or the 2015 models.
The older stuff was 3c rated.

We're any of them actually officially "rated" at 10C ?
I know some of the early "sardine can". Cells were tested Could discharge at 10c.....but how much sag etc would you accept ?

....Ok thanks guys. I have some 2012 modules. They only hold about 55-56Ah in them, but I'm able to pull 640A at peak out of them. So I call that about 10-11C. Eventually when I have to upgrade this pack I want to be sure I can get a bit more power from them.

Yes, but as above at what voltage sag, and how much heat generated ?
Also, was that a dead short discharge ? If not, you might find you could get 20+ C discharges.!
Do you see my point about there being no "standard procedure ". For C rate testing .

 

[Nuts&Volts]

....Ok thanks guys. I have some 2012 modules. They only hold about 55-56Ah in them, but I'm able to pull 640A at peak out of them. So I call that about 10-11C. Eventually when I have to upgrade this pack I want to be sure I can get a bit more power from them.

Yes, but as above at what voltage sag, and how much heat generated ?
Also, was that a dead short discharge ? If not, you might find you could get 20+ C discharges.!
Do you see my point about there being no "standard procedure ". For C rate testing .

This report shows that the cells can handle 9-11C peak discharge...http://media3.ev-tv.me/DOEleaftest.pdf

This page shows the cell doing slightly less than 3C continuous test. http://www.eco-aesc-lb.com/en/product/liion_ev/

Both of these pages refer to the original cells. I believe these are accurate for cells before model year 2015. 2015 model year battery are called Lizard packs apparently...

I did two 600A+ pulls. Starts just below 90% SOC. Data from a CA. First was average 3.47V/cell at 606A and then average3.4V/cell at 640A. Usual riding is at 1.5C rate. Cells only ever get warm to the touch. Not concerned about heat as 10C+ is only for 1-3sec max before I'm going >90mph

 

[Arlo1]

I think the 10c rated leaf cells started rolling out in the late 2014 models or the 2015 models.
The older stuff was 3c rated.

We're any of them actually officially "rated" at 10C ?
I know some of the early "sardine can". Cells were tested Could discharge at 10c.....but how much sag etc would you accept ?

For a peak discharge rating I would expect the cell not to sag any further then the nominal rating and I would expect the temp to stay in check.
For a continuous discharge I would expect the rating to be based on the amount of heat coming out of the cell the energy it can produce and the cycle life.
Luke would be the guy to ask more specifically.
I believe the pre 2015 cells are 3c continuous rated and the 2015 cells are 10c continuous. Not sure what the burst is.... 15c?

 

[agniusm]

Did someone tried to take apart new design cells? Any links?

 

[Hillhater]

Did someone tried to take apart new design cells? Any links?

From the previous page last September..
http://www.diyelectriccar.com/forums/showthread.php?p=678050&posted=1#post678050
They don't get all the way to individual cell to cell connects, But full module break down is shown.

 

[agniusm]

Thanks, that's great. on page 3 you can find leaf models for GEN1 and GEN2 cell modules.

 

[Noq]

Hi,

I've got 10 of the 2015 modules wired in series. I kept them stock at 2S2P so that's 84V max @ ~60Ah. Can anyone recommend some good charging equipment? I'm having trouble finding what I need.

Thanks

Edit: Went with this, toned down to 15A so as not to risk tripping the breaker.

 

[cycleops612]

re
"
mistercrash wrote:
I'm used to see the voltage coming down fast at the beginning to a certain point then hit a plateau for some time until it drops down at the very end of the discharge.

Only LiFePO4 have those characteristics.
"

Perhaps only proper batteries have those characteristics?

Its not a good look for a vehicle to be weaker as the trip progresses.

Add overcapacity and weight? Sure, but it aint apples with apples.

 

[LeftieBiker]

Both of these pages refer to the original cells. I believe these are accurate for cells before model year 2015. 2015 model year battery are called Lizard packs apparently...

I'm just passing through here tonight, but I thought I'd add a little info that might save someone some capacity loss down the road. The 2013+ Leaf packs *built beginning in April of 2013* better resist both age and heat-related degradation. It isn't clear if Nissan actually started building "Lizard packs" in April of 2013 but didn't want to announce it until they had real world results, or if the 4/13 - 2015 packs are just using better chemistry packs. In either case I suggest you keep two things in mind:

* 2013 Leaf cells made from January through March of 2013 appear to be no better at resisting degradation than 2011-2012 cells. I call these early 2013 packs "Canary packs" because they are much less robust than the later version. Consider these early 2013 cells to be the same in durability as 2012 cells, not better. This conclusion comes from data posted from Leaf auctions that listed both build date and capacity bars remaining, and from anecdotal evidence posted at mynissanleaf.com. Some Leafs built in early 2013 have already lost at least 3 capacity bars, and possibly four. Those built after 3/13 usually continue to show either 11 or 12 of 12 bars - many with all 12 bars after tens of thousands of miles. My own 2013 leaf SV, built in April of 2013 (whew!) still has 12 bars, with about 11% capacity loss.

* Even the "Lizard pack" will degrade fairly quickly in extreme heat. Leaf drivers in Arizona and similar places are experiencing capacity bar loss that is roughly comparable to the first generation cells. So if you use Leaf cells from even a 2015 (and probably 2016) pack, find a way to keep them from regularly getting above about 90F. Don't assume that you have a "Lizard EV" that will happily roast in 90F+ degree temps and not lose capacity. It would also be wise to not let these cells sit at 100% (actually about 95%) indicated charge for more than a few hours, if possible, and especially in hot weather. No lithium battery "likes" to be nearly full for long, and Leaf cells may like it even less. Heat, though, is still their #1 enemy.

 

[cycleops612]

"No lithium battery "likes" to be nearly full for long" seems inarguable, but how to pragmatically accommodate this?

Various, but in essence, I aim for a 80%~ charge up after use, and try and remember to put on the charger an hour or so before egress - like before i shower.

So, its Sometimes full, but not for long, sometimes 90-95% - meh.

Intuitively i like that the chemical brew is usually warmed up and active when i set off, especially if max power is needed at the outset of the trip.

They also seem to hate it if u r away for ~a month or so. A natty trick is a mechanical wall socket timer which charges for a mere ~15 mins a day in u absence.

 

[LeftieBiker]

Various, but in essence, I aim for a 80%~ charge up after use, and try and remember to put on the charger an hour or so before egress - like before i shower.

So, its Sometimes full, but not for long, sometimes 90-95% - meh.

That's also what I do with my Leaf-powered Vectrix. I charge it to 14 or 15 out of 17 bars, then try for 17 right before I leave. It actually takes 90 minutes after reaching "Full" on the dash gauge to "completely" top up the pack (to about 95%) at a lower charge rate, so I'm actually charging to maybe 90%. I also put a temp sensor on top of the pack, and don't charge the bike when it reads above 76F after sitting a while (there is a 10 minute or so lag, plus probably a 5F error, on the low side, in reading the temp that way). I treat my Leaf SV similarly, but have the advantage of it having the one-model-year-only 80% charge option, making that easy...

 

[cycleops612]

Various, but in essence, I aim for a 80%~ charge up after use, and try and remember to put on the charger an hour or so before egress - like before i shower.

So, its Sometimes full, but not for long, sometimes 90-95% - meh.

That's also what I do with my Leaf-powered Vectrix. I charge it to 14 or 15 out of 17 bars, then try for 17 right before I leave. It actually takes 90 minutes after reaching "Full" on the dash gauge to "completely" top up the pack (to about 95%) at a lower charge rate, so I'm actually charging to maybe 90%. I also put a temp sensor on top of the pack, and don't charge the bike when it reads above 76F after sitting a while (there is a 10 minute or so lag, plus probably a 5F error, on the low side, in reading the temp that way). I treat my Leaf SV similarly, but have the advantage of it having the one-model-year-only 80% charge option, making that easy...

Non technical as it is, its hard to see where its wrong, and its graspable procedure for mortals.

It seems forgotten at times, that we are dealing with a chemical reaction/brew, not a wall socket or on off switch.

In that vein, i cant see why all seem to charge in a way that ekes out the max voltage of the pak. When discharge charts are examined, both liMn & lifepo4 experience a short rapid voltage drop. The charts fall off a cliff briefly from full charge. So why stress the chemicals chasing pointless targets? Perhaps if we all reduced our full charge target volts by .1-.2v, it would be little lost and much easier on the cells? This para is more a question than a statement. It may be that small voltage increment has big effect on capacity.

re It actually takes 90 minutes after reaching "Full" on the dash gauge to "completely" top up the pack

I reason that much of the final hour~ of charging is mucking around with balancing, and negligble charge is added. & also, i think balancing for very 3rd or fourth charge, sufficient. So if it hasnt finished, i sure wouldnt wait on it.

generally, i suspect the best thing u can do is charge it as slow as time allows. Yours running warm doesnt sound good. A simple work around to slow it down may be a timer switch so the charger turns off for 10 mins each hour of the day. $10-20 for a wall socket domestic ones.

 

[LeftieBiker]

I reason that much of the final hour~ of charging is mucking around with balancing, and negligble charge is added. & also, i think balancing for very 3rd or fourth charge, sufficient. So if it hasnt finished, i sure wouldnt wait on it.

Yes, that's mostly EQ, although the pack has a higher capacity than the original one, so some of it is also simple gauge error. I generally ride at 17 bars, only doing the full charge every 4-6 rides, to EQ the pack.

generally, i suspect the best thing u can do is charge it as slow as time allows. Yours running warm doesnt sound good. A simple work around to slow it down may be a timer switch so the charger turns off for 10 mins each hour of the day. $10-20 for a wall socket domestic ones.

I charge at 700 watts - less than half the maximum. The pack temp only rises about 2-3F during charging, sometimes less in cool weather. The main problem is that ambient temps can be too hot for Leaf cells. My Leaf is sitting in the driveway right now with 6 temp bars (above 5 bars is getting too warm) and they are from the air, not driving or charging.

 

[cycleops612]

I reason that much of the final hour~ of charging is mucking around with balancing, and negligble charge is added. & also, i think balancing for very 3rd or fourth charge, sufficient. So if it hasnt finished, i sure wouldnt wait on it.

Yes, that's mostly EQ, although the pack has a higher capacity than the original one, so some of it is also simple gauge error. I generally ride at 17 bars, only doing the full charge every 4-6 rides, to EQ the pack.

generally, i suspect the best thing u can do is charge it as slow as time allows. Yours running warm doesnt sound good. A simple work around to slow it down may be a timer switch so the charger turns off for 10 mins each hour of the day. $10-20 for a wall socket domestic ones.

I charge at 700 watts - less than half the maximum. The pack temp only rises about 2-3F during charging, sometimes less in cool weather. The main problem is that ambient temps can be too hot for Leaf cells. My Leaf is sitting in the driveway right now with 6 temp bars (above 5 bars is getting too warm) and they are from the air, not driving or charging.

Thats a very good point. battery location in the car is crucial. Interiors sure bake here in oz. Even under the bonnet is a worry, esp. for a dark car.

Plug in EVs are really quite elitist. U need a drive/garage. No street parking plebs allowed in that club.

 

[LeftieBiker]

Plug in EVs are really quite elitist. U need a drive/garage. No street parking plebs allowed in that club.

Heh. I have a two car garage. There just isn't any room for the Leaf, what with the two motorcycles, 5 electric bicycles (of which I only want three), spare parts I got with the Vectrix, and 30 years' worth of accumulated...stuff. Oh, yeah, and my first car, a '67 Volvo 122S. At least the parking space outside only gets sun in the morning. It only takes an ambient temp of about 82F, sustained for lots of hours, to get a parked Leaf to 6 temperature bars.

 

[Hillhater]

...Jeez !...you actually put cars in the garage ! ?
Its been many years since i did that !
I didnt pay good money for expensive paint and security locs on my cars , just so i could hide them in a garage.
No, i want value for my money !
...and the garages are for bikes , toys, tools, workshop etc. :lol: :lol:
PHEV or even EV just needs a power supply lead outside. Much safer all round.
All our new/ future city apartments are being built with garaging under the building, often multilevel, 100s of car spaces.
The thought of sleeping on the 30th floor with 200 EVs of unknown age/ quality on charge under your building might just cause me a few sleepless nights !

 

[cycleops612]

...Jeez !...you actually put cars in the garage ! ?
Its been many years since i did that !
I didnt pay good money for expensive paint and security locs on my cars , just so i could hide them in a garage.
No, i want value for my money !
...and the garages are for bikes , toys, tools, workshop etc. :lol: :lol:
PHEV or even EV just needs a power supply lead outside. Much safer all round.
All our new/ future city apartments are being built with garaging under the building, often multilevel, 100s of car spaces.
The thought of sleeping on the 30th floor with 200 EVs of unknown age/ quality on charge under your building might just cause me a few sleepless nights !

well, to both the above posts, we live in a world where it takes a device the same size as a condo bedroom to move one person. If they all had a "bedroom", god help the planet.

 

[Offroader]

Both of these pages refer to the original cells. I believe these are accurate for cells before model year 2015. 2015 model year battery are called Lizard packs apparently...

I'm just passing through here tonight, but I thought I'd add a little info that might save someone some capacity loss down the road. The 2013+ Leaf packs *built beginning in April of 2013* better resist both age and heat-related degradation. It isn't clear if Nissan actually started building "Lizard packs" in April of 2013 but didn't want to announce it until they had real world results, or if the 4/13 - 2015 packs are just using better chemistry packs. In either case I suggest you keep two things in mind:

* 2013 Leaf cells made from January through March of 2013 appear to be no better at resisting degradation than 2011-2012 cells. I call these early 2013 packs "Canary packs" because they are much less robust than the later version. Consider these early 2013 cells to be the same in durability as 2012 cells, not better. This conclusion comes from data posted from Leaf auctions that listed both build date and capacity bars remaining, and from anecdotal evidence posted at mynissanleaf.com. Some Leafs built in early 2013 have already lost at least 3 capacity bars, and possibly four. Those built after 3/13 usually continue to show either 11 or 12 of 12 bars - many with all 12 bars after tens of thousands of miles. My own 2013 leaf SV, built in April of 2013 (whew!) still has 12 bars, with about 11% capacity loss.

* Even the "Lizard pack" will degrade fairly quickly in extreme heat. Leaf drivers in Arizona and similar places are experiencing capacity bar loss that is roughly comparable to the first generation cells. So if you use Leaf cells from even a 2015 (and probably 2016) pack, find a way to keep them from regularly getting above about 90F. Don't assume that you have a "Lizard EV" that will happily roast in 90F+ degree temps and not lose capacity. It would also be wise to not let these cells sit at 100% (actually about 95%) indicated charge for more than a few hours, if possible, and especially in hot weather. No lithium battery "likes" to be nearly full for long, and Leaf cells may like it even less. Heat, though, is still their #1 enemy.

I'm looking into these leaf cells and just wanted to say that are you sure Nissan hasn't updated the way the car displays the bars? Reason is I read that Nissan took some customer cars who had excessive capacity loss and determined it was the the way the car calculated the capacity and not actual battery degradation. I assume they may have corrected this and that is why cars built after a certain period are not showing the same capacity loss.

If the guys are reporting better range then they could have updated the leaf cells.

 

[Offroader]

Just wanted to ask you guys does anyone know why these cells are rated at 1200 cycles to 80% capacity?

Why so high when most 18650 cells only have about 500 cycles to 80% capacity?