Single LEV50-cell wanted for our Citroen C-Zero

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Martin, can you tell us how do you get the module of four cells? I much cost you to have it? How much could cost the intire procedure?
 
Thanks for taking the time to document and helping us to better understand this process.
As our Mievs age this will certainly become a much more common situation that will need to be dealt with.
Please continue to share your experience
 
Hello!

Today i drove 2km to the garage with our C-Zero in hope i can use a free lifting ramp there. I thought a personal talk to the people from the garage is better then a phone call. But the garage is busy this week and the garage could not resign for a lifting ramp (last friday i had the commitment from the garage already, but no replacement cell).

I decided in impulse to drove further 3km to a petrol station in hope finding there a free lifting ramp. The cell voltage of cell 23 drops down as fast i never have seen before. The cell voltage of cell 23 drops down 690mV, all others only by 20mV. In my mind i saw already a cell voltage of 2,75V of cell 23, which will result in a shutdown of the battery from the BMS, no matter which SoC was calculated (with 23% SoC normaly much more then 5km are possible with the C-Zero).

Starting at home:

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At the petrol station:

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Maybe some hundrets of meters should be possible as i stopped at the petrol station. Then the regret - no lift ramp.

My wife towed me at home with the Golf - C-Zero was on at this Trip in gear selection D, right foot standby at the breakpedal. At a speed of round 50km/h this results in 11kW recuperation power - it was easy to handle.

caniOn view of this special trip:

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My findings: a towline should stay in each EV - it's the universal charging equipment!


Martin
 
Just wondered, with all of the Canion data and users, if there were stats that show which cells were failing the most. So of the failed cells, how many were #23?
 
Fortunately the failed cells have been at random, this is the first report for #23. So it's not a location or design issue but simply random cells that give up their life...
 
Phximiev said:
Has anyone figured out if its a bad cell or a bad connection?

Hello!

It's definitly a bad cell. As i heared there were cell production problems in the past. If you have such a bad cell in your pack and your car is under warranty, all is fine - you'll get a new 16kWh pack. If not, you can deal at your own with this problem ...

Martin
 
Hello!

Today also a lifting ramp was available to replace the defective cell 23 of my C-Zero.

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The green one ist the replacement cell:

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I have also made some videos. If the videos are ok, i'll upload a small video of this cell replacement, too.


Martin :)
 
Martin, wonderful that your replacement went well, and it looks as though you were in a private environment where you were able to take your time. In addition to the cell, did you replace any other components? Looking forward to your video and the CaniOn readings of your new cell.
 
Hello!

Batt Status before cell replacement:

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... and after cell replacement:

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Martin :)
 
Was the cell located where you expected it to be in the pack? The diagram from Malm looks like a different placement for cell 23. Does cell #1 start at the bottom (-) or top (+) of the pack?

For some reason i thought the cells were standing upright, but i see that the modules are laid over on their side and the monitoring boards are located between the top of one module and the bottom of the next. So the temperature measurements are getting contributions from both modules.

i would be concerned about the effect of gravity and the weight of the cell roll pulling down against the internal current collectors, which are just crimped to the edges of the cell roll.

CT scan of a cell showing current collectors, etc.
cell_scan-300x185.png
 
kiev said:
Was the cell located where you expected it to be in the pack? The diagram from Malm looks like a different placement for cell 23. Does cell #1 start at the bottom (-) or top (+) of the pack?
The cell replaced in Malm's drawing is here:
GBxDMmv.png

Perhaps the front and back groups of LEV50-8's are reversed?
NbwS9Zx.png


kiev said:
For some reason i thought the cells were standing upright, but i see that the modules are laid over on their side and the monitoring boards are located between the top of one module and the bottom of the next.
The battery pack is composed of ten LEV50-8 battery modules with eight 3.7V LEV50 batteries and six temperature sensors each, and two LEV50-4 battery modules with four 3.7V LEV50 batteries and three temperature sensors each, for a total of 88 LEV50 batteries and 66 temperature sensors.
The two LEV50-4 battery modules sit in the battery pack so as to have their battery management circuitry and temperature sensors mounted on top of the batteries, while the ten LEV50-8 battery modules sit in the battery pack so as to have their battery management circuitry and temperature sensors mounted on the side of the batteries.
 
Hello!

First charging after the cell replacement:

Youtube Video

Conspicuous: At 94% cell 23 does fall back in cell voltage, even till this point it has the same cell voltage to the other cells. At 97% SoC goes back to 91,5% again. Is the BMS in learning mode now? Any ideas?


Martin
 
Hello!

First trip after cell replacment - round Neusiedlersee:

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20mV diff at the beginning would be put right with the next couples of full charges. Looks ok again to me :)


Martin
 
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