Main Traction Battery Upgrade i-MiEV

[MickeyS70]

Given how extensive this thread has become already, it may be a good idea to keep the outlander discussion separate or even better, move it to the myoutlanderphev forum altogether?

 

[ChristopheFR]

They look more like guide pins for accurate positioning IMHO…

of course it is a centering system, but the small round heads remind me of a rivet. The final electrical connection would be made by tightening the nuts On the other hand, what is the purpose of the bump circled in red? is it the centering of the box lid?

 

[CeeJay09]

that bump is actually the terminal of the cathode/anode I dont know which, it is welded to that tab that has an m8 bolt for cell links and an m3 thread for bms
the m8 bolt has a large hex head that is very thin held captive by the plastic shape gismo underneath the tab and the guide pins go through that plastic bit to line up for manufacturing

 

[ChristopheFR]

ah, interesting, do you have any photos?

 

[kiev]

what is the purpose of the bump circled in red?

That is a rivet to connect the aluminum current collectors to the positive terminal (cathode). It is also directly in contact with the case.

The negative anode terminal is insulated from the case and connects to the copper current collectors, probably thru a rivet underneath the extender tab.

The higher density copper and steel shows up brighter than aluminum in xray CT scans, and you can see how there is an insulation gap between the case and the - terminal. From the 787 screamliner fire investigation report:

 

[stoatwblr]

I am looking at 90Ah batteries of smaller physical dimensions on all 3 axis.

What's the C rating of these things?

Ie: what are sustained/peak charge/discharge currents

 

[ChristopheFR]

That is a rivet to connect the aluminum current collectors to the positive terminal (cathode). It is also directly in contact with the case.

The negative anode terminal is insulated from the case and connects to the copper current collectors, probably thru a rivet underneath the extender tab.

The higher density copper and steel shows up brighter than aluminum in xray CT scans, and you can see how there is an insulation gap between the case and the - terminal. From the 787 screamliner fire investigation report:
View attachment 846

ok, we can clearly see the connections. Removing the tabs without destroying the batteries is difficult, especially since you have to do it 176 times.
Any ideas on another solution?

 

[MickeyS70]

ok, we can clearly see the connections. Removing the tabs without destroying the batteries is difficult, especially since you have to do it 176 times.
Any ideas on another solution?

Once you remove the tabs, the M8 bolts will have nothing to hold them in place and what’s left is probably only good for the bin; I mean recycling, which you probably will have to pay for.

Might be best to sell them intact for solar storage and use the proceeds to pay for custom made terminal extenders, btw there are only 9 needed per 8 cell module (+ 7 washers to keep the links level) or 100 in total for a 88 cell triplet

 

[kiev]

Any ideas on another solution?

Did you see page 1, post 11, for how paul did it using crimped ring terminals?

 

[MickeyS70]

Did you see page 1, post 11, for how paul did it using crimped ring terminals?

That works fine for cell voltages but it doesn’t make for accurate cell temperature measurements (post #14).
Unlike LEV50s, NMC cells may be damaged when charged below freezing..

 

[kiev]

NMC cells may be damaged when charged below freezing..

i wouldn't worry much about the low temperature case with it's long time constant--when it gets cold and freezing outside then it will be just as cold everywhere inside the pack over time.

i would be more worried about a quick or fast high heating event such as DCQC or 30 minutes of high acceleration runs. In this case the cell might heat up quicker than the sensor on the CMU can detect the temperature rise. But knowing that to be the case i would take countermeasures before getting off into the heat zone.

 

[fresh_milk]

I have 80 2015 LEV40 outlander cells that I recently acquired if you want/need dimensions of the cells before pulling your pack apart

Yes please mate! Any and all dimensions you can grab and photos of the pack and cells would be useful if you have the time.

Are you planning an upgrade / swap out? Or already finished?

 

[fresh_milk]

Hi all, sorry to but in being a newb. I want to also perform this upgrade, I have built booster packs for my various evs with good success and results. I am not afraid of mechanically fastening CMU boards or wiring bms components. what I do struggle with is coding and arduino things, which leads me to ask if there is a thread on the arduino DUE for this application so that I can learn it. are there any boards that I will need to make to implement this CAN bridge? if so where can I find that information? I have read this thread twice trying to find information (which it is full of) for the process, thanks in advance for both constructive and the other feedback that comes my way

CJ I am also trying to learn this and I'll put out my summary thoughts and have the experts correct me where I am wrong

1. The car uses CANbus to communicate to its various components
   1. Car Area Network
2. The software on the PHEV and MiEV is the same
3. The software is coded to utilise the standard OEM batteries
   1. If you install a battery pack with greater range, the car cannot see it
   2. You might get benefits from longer battery longevity but no extended mileage
4. To get extended mileage you need to update the car's software
   1. @piev has a lot of entries on the code
   2. I saw some talk on using the MUT3 software to update the range
5. To update the code you need a bridge
   1. It sits in the middle of the CANbus and the car
   2. In programming its called man-in-the-middle
6. This seems to be utilising an Arduino unit to act as bridge and reprogram
   1. Needs to be hardwired in so the CANbus cables will be cut
   2. Thread 1 on CAN communication using Arduino
   3. Thread 2 @Frud shows complete bridge install
   4. Thread 3 @piev details the pins for connection

That's my layman's summary notes of the process.

 

[CeeJay09]

Yes please mate! Any and all dimensions you can grab and photos of the pack and cells would be useful if you have the time.

Are you planning an upgrade / swap out? Or already finished?

I was asked to keep all outlander discussions separate so i started a new thread for outlander and my booster packs etc
https://myimiev.com/threads/booster-battery-for-imiev-and-outlander.5602/

 

[kiev]

dd

 

[MickeyS70]

CJ I am also trying to learn this and I'll put out my summary thoughts and have the experts correct me where I am wrong

You pretty much nailed it, just a few clarifications

1. The car uses CANbus to communicate to its various components
   1. Car Area Network

Yes, but has also other means of communication

2. The software on the PHEV and MiEV is the same

Don’t think so the PHEV is far more complex as it’s EV-ECU has to run both ICE and EV components, but if you mean the BMU I agree, it should be coded similar to a triplet

3. The software is coded to utilise the standard OEM batteries

Yes, 88/80 LEV50x for EV, 80 LEV40 for PHEV

If you install a battery pack with greater range, the car cannot see it, you might get benefits from longer battery longevity but no extended mileage

Yes, the car keeps a record of the current battery capacity, if you replace the battery without ‘telling’ the car your range will remain the same and may even decrease slowly as the BMU cannot correctly update the capacity

• To get extended mileage you need to update the car's software
  1. @piev has a lot of entries on the code

Yes, ideally you would change the programming of the ECUs but that’s not possible presently, hence the need for a CAN bridge

• 1. I saw some talk on using the MUT3 software to update the range

You can reset the battery capacity to stock range but no further using MUT3

• To update the code you need a bridge
  1. It sits in the middle of the CANbus and the car
  2. In programming its called man-in-the-middle

The BMU will always run stock code, the bridge is put between the BMU and EV-ECU. It intercepts all data packages, modifies some and then passes them on.

• This seems to be utilising an Arduino unit to act as bridge and reprogram
  1. Needs to be hardwired in so the CANbus cables will be cut
  2. Thread 1 on CAN communication using Arduino
  3. Thread 2 @Frud shows complete bridge install
  4. Thread 3 @piev details the pins for connection

There are may different ‘flavours’ of Arduino, the code @piev has provided is written for an Arduino Due, the pinout is correct for a triplet, but may be different on an Outlander

 

[piev]

1) The cells were 88 mm tall LEV50's are 98mm so I added fillers so the cells would not move around. The are also thinner and so I added felt spacers between cells as well.
2) The length is a few mm longer and I had to use a Dremel tool to remove some of the plastic case so the cells did not distort the plastic case. I could force them in but it tore the blue shrink wrap and made the case bow. (171mm vs 174mm)
3) Yes, you still need to reset the capacity using a MUT3 or some other device. It will only reset to 48Ah. So the bridge allows you to use the 93Ah capacity.

BTW, for anyone following this thread. Attached is our latest version of the Bridge code.

I was informed that I left my code in this version that masks my CMU board error. So here is a version without that code.

BTW it's called a Controller Area Network or CAN bus.

 

[CeeJay09]

Yes, the car keeps a record of the current battery capacity, if you replace the battery without ‘telling’ the car your range will remain the same and may even decrease slowly as the BMU cannot correctly update the capacity

Im not sure this is 100% correct, I added newer better capacity imiev lev 50 cells (all tested) from another car and over several full discharges below 4km on Gom and subsequent full balance charges the car has now increased its range above 100kms.
From the research into the upgraded CAN bridge it appears the imiev simply has a maximum range on the GOM too. But this could just be forum nonsense as this thread seems to have the code working and I don't know how the code works yet.

 

[kiev]

Well, up till now this has been a fairly no-nonsense forum, especially when compared to many others. High signal-to-noise ratio for technical content, etc.

The edit button mostly works for making corrections to ensure we are sharing good information. Or a mojulator can make edits/corrections.

 

[MickeyS70]

I added newer better capacity imiev lev 50 cells (all tested) from another car and over several full discharges below 4km on Gom and subsequent full balance charges the car has now increased its range above 100kms.

Yes, that is correct if you replace LEV with LEV however when you use NMC chemistry the BMU’s capability to recognise the added capacity doesn’t work, unfortunately.

OBDZero did an excellent description of the issue below:
https://www.goingelectric.de/forum/viewtopic.php?t=82690&start=60

From the research into the upgraded CAN bridge it appears the imiev simply has a maximum range on the GOM too. But this could just be forum nonsense as this thread seems to have the code working and I don't know how the code works yet.

It may well be possible that there is a limit how much range the GOM can display, but using 93Ah cells isn’t going anywhere near it…