Enerdel battery module disassembly

[Ratking]

Hello guys,

I got my fingers in a couple of these modules in my search for Leaf batteries. They seems good and they are a bit smaller than a Lead cell. That makes it easier to build a pack for a bike. My main problem is identifying what cell it is. I hope they are the high discharge ones, and not the 3C high energy density.

I got some pictures from the process of taking parts of the module apart. I am trying to charge a cell to see how much it holds.

[http://endless-sphere.com/forums/download/file.php?mode=view&id=164488&sid=26242c7a67131706b5f53bfc7d3a1635/img]

[img]http://endless-sphere.com/forums/download/file.php?mode=view&id=164489&sid=26242c7a67131706b5f53bfc7d3a1635

 

[Ratking]

Just a simple charge, I hope the cheap charger at least measure right.

 

[Nuts&Volts]

If you search on DIY electric car you can see that the 3C cont cells can still put out 7-8C+. Major on DIY tested them out.

 

[pm_dawn]

Those cells can be found in some of the newer Think cars.
They have a really big pack of them.

Did you get your multimeter from Biltema ?

Regards
/Per

 

[Ratking]

Those cells can be found in some of the newer Think cars.
They have a really big pack of them.

Did you get your multimeter from Biltema ?

Regards
/Per

Yeah, the pack I have parts of is 23Kwh, so quite large for a car as small as a Think. Thats a Biltema multimeter

 

[Ratking]

If you search on DIY electric car you can see that the 3C cont cells can still put out 7-8C+. Major on DIY tested them out.

I've been PM'ing Major and he said the same. I tried to make some rough estimates from the datasheet where they claim a powerdensity of 1250w/kg. Two cells weighs 860g with a capasity of 35Ah. P=UxI, so 1250=3.6x35xC
1250\3.6X35=C, C=9.9
Given that I am missing 140g of cells in the above equation it is a bit of, but still impressive(If my math holds true that is)

 

[major]

When judging a battery or cell for pure power performance, the Short Discharge Time is a useful parameter or tool to use. Here is a white paper on it and a chart with popular cells including this EnerDel product. Interesting that it fairs better than the A123 20Ah cell. I do realize that this technique does not consider the longer duration duty and effect on the life of products. But many believe that the life is primarily influenced by the temperature and voltage. Anyway, it is another set of data for you.
http://elithion.com/wp_short_discharge_time.php

 

[Ratking]

When judging a battery or cell for pure power performance, the Short Discharge Time is a useful parameter or tool to use. Here is a white paper on it and a chart with popular cells including this EnerDel product. Interesting that it fairs better than the A123 20Ah cell. I do realize that this technique does not consider the longer duration duty and effect on the life of products. But many believe that the life is primarily influenced by the temperature and voltage. Anyway, it is another set of data for you.
http://elithion.com/wp_short_discharge_time.php

Thank you Major, I got one module to test and I have to make a decision if I want the rest of the batterypack or not. How do you think Enerdel compares to Leaf cells?
I like the concept of having one larger cell compared to many cells in paralell, fewer connections that go bad. But I can get Enerdel cells much cheaper.

On another note, I discharged one cell from 4.1v to 3.0v with 1\17.5c current. I got 11,5Ah out from the cell. Looking at the graph from the datasheet it indicates a capacity loss of 20%. So the cells I have is not new, I guess between 1000-1500cycles. Enerdel claims that they got much more life in them still, but that is quite the capacity loss.

 

[whatever]

just wondering if you can describe the 'foam' used between cells?
Is it very compressable i.e. soft or hard?
Is there much compression on the cells when in the pack?
a quick google search seems those batteries are from around 2011, used in volvo c30 electric car and others.

 

[Ratking]

just wondering if you can describe the 'foam' used between cells?
Is it very compressable i.e. soft or hard?
Is there much compression on the cells when in the pack?
a quick google search seems those batteries are from around 2011, used in volvo c30 electric car and others.

My impression is that the cells is under little compression(they are stacked together, but not with much force).
The mechanical construction does not support much compression and the foam is really soft. It will easily be compressed flat between two fingers.
The complete module is compressed with four aluminum bolts going trough the module, but the cells themselfe is not compressed more inside the plastiv frame from the bolts.

I will take a better look and update the post if my preliminary assassment is wrong.

 

[major]

On another note, I discharged one cell from 4.1v to 3.0v with 1\17.5c current. I got 11,5Ah out from the cell. Looking at the graph from the datasheet it indicates a capacity loss of 20%. So the cells I have is not new, I guess between 1000-1500cycles. Enerdel claims that they got much more life in them still, but that is quite the capacity loss.

Full discharge is down to 2.5V/c. When I was testing, they used 4.2V/c as the starting point. Most of my tests started between 4.1 and 4.2 and cutoff at 2.5V/c. I would think capacity loss would be less than 10%, more like 5 - 7% for 3 or 4 year old cells. The cells I have are from 2011 and I have seen no measurable loss. You can see some of my tests here: http://endless-sphere.com/forums/viewtopic.php?f=31&t=50535&hilit=EnerDel+for+sale

I have not touched a leaf cell or seen good tests to compare to EnerDel. Although I have heard about pleased users of the Leaf and also of salvaged Leaf cells.

 

[Ratking]

On another note, I discharged one cell from 4.1v to 3.0v with 1\17.5c current. I got 11,5Ah out from the cell. Looking at the graph from the datasheet it indicates a capacity loss of 20%. So the cells I have is not new, I guess between 1000-1500cycles. Enerdel claims that they got much more life in them still, but that is quite the capacity loss.

Full discharge is down to 2.5V/c. When I was testing, they used 4.2V/c as the starting point. Most of my tests started between 4.1 and 4.2 and cutoff at 2.5V/c. I would think capacity loss would be less than 10%, more like 5 - 7% for 3 or 4 year old cells. The cells I have are from 2011 and I have seen no measurable loss. You can see some of my tests here: http://endless-sphere.com/forums/viewtopic.php?f=31&t=50535&hilit=EnerDel+for+sale

I have not touched a leaf cell or seen good tests to compare to EnerDel. Although I have heard about pleased users of the Leaf and also of salvaged Leaf cells.

My calculations was based on the datasheet showing a start voltage of 4.1v and end voltage of 2.5v. By using their graph I saw how many Ah I should ideally have at 3.0v. But I would have to discharge a full cel down to empty to be comletely sure. Are you positive that the cell is able to handle 4.2v?

Too bad the cells cant be connected in xs1p, I am thinking about making a PCB for this. 2p is a bit too large for a e-bike.

 

[major]

Yes, I have done numerous tests on 12S2P modules with the 4.2V/c end of charge. I have even occasionally exceeded 4.2 by a tenth or 2. No immediate downsides were apparent. And I have not noticed any long term adverse affects over 3 or 4 years and maybe hundreds of cycles.

 

[Ohbse]

My calculations was based on the datasheet showing a start voltage of 4.1v and end voltage of 2.5v. By using their graph I saw how many Ah I should ideally have at 3.0v. But I would have to discharge a full cel down to empty to be comletely sure. Are you positive that the cell is able to handle 4.2v?

Note that on these discharge graphs the reason they appear to start from 4.1v or even lower in some cases is due to voltage sag at that particular discharge rate. Resting voltage is definitely going to be 4.2v to start. Difference between 4.1 and 4.2 is commonly ~10% which will account for some of your lost capacity

 

[Ratking]

Yes, I have done numerous tests on 12S2P modules with the 4.2V/c end of charge. I have even occasionally exceeded 4.2 by a tenth or 2. No immediate downsides were apparent. And I have not noticed any long term adverse affects over 3 or 4 years and maybe hundreds of cycles.

Thank you, I will do some more testing with full voltage range.

 

[Ratking]

My calculations was based on the datasheet showing a start voltage of 4.1v and end voltage of 2.5v. By using their graph I saw how many Ah I should ideally have at 3.0v. But I would have to discharge a full cel down to empty to be comletely sure. Are you positive that the cell is able to handle 4.2v?

Note that on these discharge graphs the reason they appear to start from 4.1v or even lower in some cases is due to voltage sag at that particular discharge rate. Resting voltage is definitely going to be 4.2v to start. Difference between 4.1 and 4.2 is commonly ~10% which will account for some of your lost capacity

Yeah, it is possible that the cell still got most of its capacity, I'll do some more testing. Still strange that nominal voltage for this cell is 3.6v and the high discharge cell is 3.7v(both from Enerdel). I think that voltage difference for the cell and the fact that the start voltage for the graph was 4.1v was the reason I concluded that 4.1v per cell was maximum voltage.

 

[336v]

Hi Ratking (and all),

Does anyone knows the pinout of that ribbon connector on EnerDel
pack connecting cells and thermistors to RLEC module?

Anyone who took a pack apart for any reason, can easy see
which trace (e.g. pin of the FCI connector) goes where.

Voltages are actually trivial to measure, but the temp sensors are not.
Also duplicate traces/pins (same measurements) may be tricky to determine
how they are connected to cells.

Anyway, any sure info on the pinout is greatly appreciated.

Thanks!

 

[Ratking]

Hi Ratking (and all),

Does anyone knows the pinout of that ribbon connector on EnerDel
pack connecting cells and thermistors to RLEC module?

Anyone who took a pack apart for any reason, can easy see
which trace (e.g. pin of the FCI connector) goes where.

Voltages are actually trivial to measure, but the temp sensors are not.
Also duplicate traces/pins (same measurements) may be tricky to determine
how they are connected to cells.

Anyway, any sure info on the pinout is greatly appreciated.

Thanks!

Hello

I don't have any pinout and wont use the ribon cable/connector, but I can take pictures of the ribbon cable when dismounted and flat.
That may help you with identifying the traces and where they go.