Nissan Leaf Cells Test Data

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Hillhater   100 GW

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Re: Nissan Leaf Cells Test Data

Post by Hillhater » Oct 23 2016 3:52am

.??..you do know the leaf uses "pouch" cells , not 18650 cells ??
Why wouldnt they be rated for 1200 cycles ? They are purpose developed and made specifically for the Leaf and presumeably tested to enable that claim to be made.
....And there are several 18650s with similar and higher cycle life figures.
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Re: Nissan Leaf Cells Test Data

Post by Pajda » Oct 23 2016 4:02am

Offroader wrote: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?
I can give you one answer based on my measurement and observation. There are two general categories of Li-Ion cell.
1) Best available energy density cells
2) "Robust or durable" cells

The first category is characterized by maximum achievable energy density at a given time. However, at a cost of lower cycle and lifetime, lower power density and intrinsic safety. We are talking about 700Wh/l for modern cells in 18650 size. It should be also noted, that there were made no significant progress in increasing energy density here from 2012.

The second category is logically an opposite to the first. So those cells are very good in every aspect exept the energy density. But in this category was made a huge progress. From 2012 it starts at 314Wh/l (Leaf 24kWh cells) for best pouch cells and now in 2016 we have about 550Wh/l (new LG cells).

So you can not compare Leaf cell and a modern high density 18650 cell. But I an quite sure that you can find a 1500mAh (320Wh/l) 18650 cell (e.g. for power tools) which will have the same or even beter cycle life and other parameters than Leaf cell.

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Nissan Leaf Cells not suitable for outdoor use?

Post by marcexec » Jun 24 2017 4:36pm

Sorry to hijack the thread but I have a potentially serious concern.

I have 12 modules / 24s of 2012 AESC modules from a Leaf in my motorbike. Today just before making the last connection from positive to the contactor I accidentally touched the lead to the chassis, had a spark and some copper welded. The chassis is obviously not supposed to carry HV-, not even 12V-, typical on a motorbike.
At first I suspected the negative lead around the fuse and the Kelly controller, but they have no continuity to ground. A full short at 92V would have been much more disastrous and should have blown the fuse. With a multimeter I measured voltages of up to 1.6V to ground from various points of the pack. The voltage only registers briefly.
I disconnected all the leads and even the interconnect to isolate - no luck.
I removes the lower 4 modules and took the whole harness off.
Now I can measure from various points and have the same thing all over the place, nearly every 2nd connector register 0.1-0.3V briefly, even on the 4 modules that are now completely removed from the bike. Double-checked with a 2nd multimeter as I thought I'm going crazy.

I am suspecting that the exposure to the elements has breached some kind of seal and I have a "bit of a short" to the cans. The obvious questions:
- Can anyone else confirm this?
- Is this a big issue? HV leads anywhere have to be handled carefully anyway. Kelly & contactor will be driven by dedicated LV pack, but should I isolate the controller from ground? They are known to have some ground issues. I could isolate the individual modules on the lower pack, but the upper one is a bespoke, tight fit...
- Anything else i should test?

A picture:
Image
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zEEz   1 kW

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Re: Nissan Leaf Cells not suitable for outdoor use?

Post by zEEz » Oct 13 2018 3:59am

marcexec wrote:
Jun 24 2017 4:36pm
Now I can measure from various points and have the same thing all over the place, nearly every 2nd connector register 0.1-0.3V briefly, even on the 4 modules that are now completely removed from the bike. Double-checked with a 2nd multimeter as I thought I'm going crazy.

I am suspecting that the exposure to the elements has breached some kind of seal and I have a "bit of a short" to the cans. The obvious questions:
- Can anyone else confirm this?
Hi!
I just now tested my Leaf 2012 modules and there is a consistent reading of 20mV between any battery lead and the aluminum can... :idea:
Didn't check the current involved, but it is real, since contacting 2 different parts of the module can gives exactly 0mV.
In my case I suppose it is nothing to worry about. I bought them in 2013. It is just a few days that I put them in operation in my e-bike.
They sitted untouched for 5 years and they lost a fairly small amount of charge, very evenly accross all cells.

Have fun!
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zEEz   1 kW

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Re: Nissan Leaf Cells Test Data

Post by zEEz » Oct 13 2018 5:06am

Image

This is a picture of one of the 2 battery packs created filling Decathlon side bike packs with Nissan 2012 modules.
For an e-bike that is having a range of 200km at 35kmh speed.

Have fun!
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Punx0r   10 GW

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Re: Nissan Leaf Cells Test Data

Post by Punx0r » Oct 15 2018 8:22am

Is it just one can out of several that's showing leakage between can and terminal?

Unrelated, but I'd put some insulation around the barrels of those crimp terminals to stop them touching the casing if bent!

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zEEz   1 kW

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Re: Nissan Leaf Cells Test Data

Post by zEEz » Oct 17 2018 10:59am

Punx0r wrote:
Oct 15 2018 8:22am
Is it just one can out of several that's showing leakage between can and terminal?

Unrelated, but I'd put some insulation around the barrels of those crimp terminals to stop them touching the casing if bent!
I was answering to marcexec... He has some leakage, mine seems ok...

I didn't put insulation around the barrels of those crimp terminals, since there is no chance they can be bent enough to contact the can...
It seems close in the picture, but really the clearance is huge... And I use the barrel of the terminals to probe and balance the single cells...
It is very convenient...

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Punx0r   10 GW

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Re: Nissan Leaf Cells Test Data

Post by Punx0r » Oct 17 2018 4:09pm

Fair enough, the distance looked shorter in the photo :)

Warren   100 kW

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Re: Nissan Leaf Cells Test Data

Post by Warren » Jan 10 2019 11:29am

The new 62 kWh Leaf is coming out soon. The cells are still made by AESC, not LG. I have not heard what the chemistry is, but I have to guess it is now NMC.

The pack is 288 cells, 96s3p. The sardine cans are gone. The plastic framed cells are presumably welded together in threes, and are stacked in frames holding 27, 12, or 21 cells each.

https://d2t6ms4cjod3h9.cloudfront.net/w ... 98x599.jpg

https://d2t6ms4cjod3h9.cloudfront.net/w ... 98x599.jpg

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