Battery cell failing at just 2900 km (1800 miles)

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JoeS said:
Gyver, that's great information! Now, let her slowly charge up fully, and what happens?
Click to expand...

My slowest charge is with my stock evse at 10 amps, 220v (standard here).
this is the battery status after a full charge this morning:
https://drive.google.com/file/d/0B2nh4ZMDv45eOHNFcWJSRWlDQnc/view?usp=sharing
clearly the 2 faulty cells have a lower voltage and SOC tops out at 91.5%

then I drove the car just for a moment and plugged it in again to see how it behaves with charging currents.
Normally, when the battery is empty, the charging current shots up directly at 10 amps. In this case it slowly ramps up, peak at 6 amps, then slows down:
https://drive.google.com/file/d/0B2nh4ZMDv45eNnJNNmdncTJZdTg/view?usp=sharing

after some minutes canonIon shows just a 1-2 amps withdrawal that continues for quite a long time. I suppose it is the cell balancing sequence:
https://drive.google.com/file/d/0B2nh4ZMDv45eQTJQN0VZUk1iR1E/view?usp=sharing
 
Gyver, thanks for posting. Yes, two cells and maybe a third. As PV1 said, this is the first time we've seen multiple cell failures.
Gyver said:
...It was used as a demonstrative vehicle in 2012/2013 (exp. date of its last insurance was October 2013) and then it was left alone for 2 years....
Click to expand...
I can't help wondering at what SOC the car was left alone, as conventional wisdom tells us that leaving lithium-chemistry batteries fully charged, especially if exposed to higher temperature, is a recipe for murder...

Anyway, great that you are getting a new pack, and hopefully it will be 16kWh, and soon...
 
JoeS,
that was quite a special car, they displayed it in some cities, and just for 1 year. In Milan I know they used a ChaDemo charger (somebody told me at Citroen), in the other cities they had a Mennekes to Yazaki cable (I received that too with the car). then it has been left alone between 2 and 3 years. When I took it the tyres were flat, 12v battery dead, but at 2900 kms the car was like new. I bet they stored it at 100% SOC.
 
I made a new experiment.
I ran the car with full charge (91.5% SOC in my case) till it stopped completely (0% SOC). Thanks to CanIon I managed to calculate when I needed to approach home (driving very slowly).

SOC history:
https://drive.google.com/file/d/0B2nh4ZMDv45eampFa2lnZ1lnMG8/view?usp=sharing

Batt status @ 5% SOC:
https://drive.google.com/file/d/0B2nh4ZMDv45eRTdPNEZoU01vNkU/view?usp=sharing

Batt status @ 1.5% SOC:
https://drive.google.com/file/d/0B2nh4ZMDv45eX09hLUcySTB1TlE/view?usp=sharing

Batt status @1% SOC (While slowly driving):
https://drive.google.com/file/d/0B2nh4ZMDv45eR1prZFNISmZEUW8/view?usp=sharing

batt status @ 0,5% SOC:
https://drive.google.com/file/d/0B2nh4ZMDv45ebnlxT2x0UEZaX1E/view?usp=sharing

batt status @ 0% SOC:
https://drive.google.com/file/d/0B2nh4ZMDv45eWVBkbTRRdVV3M2c/view?usp=sharing

cells temperature after completely draining the battery (outside temp was 7° C):
https://drive.google.com/file/d/0B2nh4ZMDv45eWEZmM0RJSV9kcDg/view?usp=sharing
 
Good screenshots, dramatically showing your battery pack problem. Isn't CaniOn great! Battery temperature at 20.3degC at 0% SoC is very comfortable, even with 7degC ambient. I wouldn't hold my breath that those two cells will rejuvenate - actually, do NOT wish them to, as you are expecting a new pack under warranty. In the meantime, happily drive your silent workhorse and enjoy it, recognizing that you have somewhat diminished range.
 
thank you Joes,
I am enjoying it, and even having fun experimenting with it, knowing in some days I will have a new pack. Cells won't rejuvenate, even the technician at Citroen told me that. He told me cycling the battery with deep discharges / full recharges will probably give me some range gain but can't fix defective cells. Once they are gone, they are gone.
Besides driving full electric in Italy is very nice, it is the only private vehicle (besides taxis) to have access to the old town centres (very very old, the white marble bridge I cross every day is 2100 years old..), ICEs stay out.
 
Surprise surprise!
after discharging the car completely (to a complete stop), I fully recharged. To my surprise I now have all the bars on the "tank" gauge, this is the first time it ever happens :shock: . When I first had my car in December it showed just 12 bars when fully charged. CanIon now shows "100% SOC" while until yesterday it showed maximum 91.5% when fully charged. I still have 109 kms on the rr gauge, and I still can see the bad cells, so I think my c-zero has just recalibrated the SOC gauge to show 100% representing the maximum my pack can achieve, not what it is supposed to.

batt status @ 100% SOC:
https://drive.google.com/file/d/0B2nh4ZMDv45eS19tTjdBV0ZNOTA/view?usp=sharing
 
Permament usage of defective lithium battery is never a good idea. :eek:

Apart from this, any news on the topic? Replacement arrived?

How much would it cost to replace the battery out of warranty?
 
jumpjack said:
Permament usage of defective lithium battery is never a good idea. :eek:
Click to expand...

Don't be harsh- this recalibration has been long-reported by Malm, so it's good to get confirmation that it'll even happen with defective cells, meaning that to a clueless procrastinator, the problem could 'fix itself' with just some reduced range. That would deprive owners of warranty replacements, and could result in some of them getting stranded with bigger problems as the failed cells continue to be stressed, becoming hot spots in the pack, etc...
 
Hi Jumpjack,
Well, I still have the old pack. It seems Citroen had issues in receiving the new pack from Japan. Now it seems it has finally arrived in Italy last week, so they should call me in the next days... maybe... Meanwhile my battery pack is always better, now it shows 120 kms on the RR gauge when fully charged.
I know a person inside Citroen, he told me the new pack costs Citroen about 17000 euros.
 
Did the two cells come up closer to the others also? Before it was about 35mV difference, which is not bad at all and could be an instrumentation issue rather than bad cells.
 
Kiev,
3 readings with canion with 3 different soc, 1 with evbatmon. I took these readings before taking the car for the "cure". Oddly enough those readings seems quite good to me. How is it possible that I started with 80 kms RR with just 12 bars and I end up 4 months later with 16 bars, 120 kms RR and quite a balanced pack is a mistery to me. Maybe it is something related to the 3 years the car has been left alone

https://drive.google.com/file/d/0B2nh4ZMDv45eVkx0QUlMb0FENDA/view?usp=sharing
https://drive.google.com/open?id=0B2nh4ZMDv45eZjlDZ09HUTJYbnM
https://drive.google.com/open?id=0B2nh4ZMDv45eb29yLWtJMjBFMHc
https://drive.google.com/open?id=0B2nh4ZMDv45eb25PNGJRc3l1eTg

my car is actually at the dealership, next week I shall have a c-zero with a new battery pack
 
Looking at those plots it appears that the pack is good and has no problem, the 5mV difference between max and min is excellent and at the limit of resolution of the measurement.

If a cell is truly damaged or defective then it won't heal or recover, but your plots seem like the issue is due to something reading or reporting an incorrect voltage in the measurement circuit on the CMU board. So was it bad cells or bad board?

It is not possible to determine the issue without removing the module and testing each cell individually, and testing or replacing the CMU board--so the solution is a new pack for you!
 
I received my car back last week.
So, how does my new battery-pack look like?

https://drive.google.com/open?id=0B2nh4ZMDv45eLTI3STVzWEJJaDQ
https://drive.google.com/open?id=0B2nh4ZMDv45eR1JZM2NKSEZaMG8

It is better than I thought: 2 days ago I drove 78 kms using 50% of charge (driving easily trough slow roads, 50 - 70 kph) meaning I should be able to drive nearly 160 kms on a single charge.
Today I had to take the motorway. Driving @ 100 kph I used 27% of charge for 36 kms, meaning I should be able to drive around 130 kms on the motorway on a single charge.
that's about 1/3 more of what I could achieve with the old pack.

I am a happy EV owner! :D
 
Gyver said:
So, how does my new battery-pack look like?
Click to expand...

Thanks heaps for posting, that's the highest capacity we have recorded so far. 45.8 is a great benchmark for a "new" battery by the time it gets to a customer. I see it looks like the battery was shipped from Japan only when it was required for your iMiEV, here in Australia they don't seem to hold battery stock either. Your battery should be very new unless it was sitting in the factory for a while.
 

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