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Paper on second life for notebook batteries
#1
Hi guys,

I'm new here. I'm doing my PhD on this topic and recently I published my first paper.
I'm sharing it here because this website has been a great source of inspiration, thanks!
Unfortunately, I didnt had the means to publish it open access, but the article can be downloaded for free before 25.06.2019 using the following link: https://authors.elsevier.com/a/1Z0AI,rUrFY7Kl   

Best regards,
F
completelycharged and thunderheart like this post
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#2
Your conclusion ......

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#3
Where can you get a PhD on cells ? I'll join-in !
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#4
Interesting paper,
Can you get data from the tester in Fig5 to go this route : https://secondlifestorage.com/t-Charge-a...-data-help
Also
https://secondlifestorage.com/t-Developm...2#pid49742
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#5
(05-15-2019, 11:36 AM)fsalinas Wrote: Hi guys,

...................I'm new here. I'm doing my PhD on this topic and recently I published my first paper.
I'm sharing it here because this website has been a great source of inspiration, thanks!...................

Best regards,
F
According to your conclusion,


Hmm looks like I must be doing something wrong or I am incredibly lucky. Or I should get my PhD on Li-ion salvage for a second life. Tongue 

Here is my cost per cell analysis and my findings.
Initially I was paying $1.50 per pack at my recyclers whom I visit once a month. Since October 14th I have been there 6 times.
The last time was April 26th and the price has been reduced to $1.00 per pack.
I was able to choose and pick my packs . Medical, Powertool, and of course Laptop. I tended to go with the 9 cell and when they were gone the 6 Cell. The first five trips I collected 200 packs for $300.00 each time. So 1000 packs for $1500.00. My last trip I collected 250 packs for $250.00.
So my total pack collection (not including the ones given to me from several other sources, probably another 200 or so) was 1250 packs.
We will use our calculations with just the purchased cells as to make the point.
Now lets do some PhD math.
1250 packs with an average of 7 cells is 8750 cells with a cost of $1750.00. that is $0.20 or 20 cents per cell.
Now out of those 8750 cells there were cells with physical damage as in rust dents and leakage around 5%.
~2000 of those cells where never counted in the spreadsheet as such as I did not start my Harvested Cell Analysis spreadsheet till 12/13/2018 and they were not up to the standards any way so no need to enter them, but they are counted as the total of cells.

My criteria is a little stricter than the research paper as I reject any cell with <80% (they are at <70%) capacity and the cells have to have a mAh capacity of ≥2200mAhs which is a criteria they did not include.

So that brings me to my total of 2512 cells that meet my criteria and I still have 75 packs to open and test. Oh and by the way my average mAh is 2412.50 per cell.
So let see $1750.00 ÷ 2512 = 0.69665....... per cell. Let's say 70 cents per cell.
So I looked up the cheapest "decent" 2400mA they run ~$4.00.
Let's add some other parameters into the mix and see if we can get closer to the lets buy new price range.
The kWh to test and analyze the batteries. lets say 400kW at .013 per kW is $52.00 (50% of that is taken care of by solar though)
Gas to go to the recycler( an hour drive) each way.  6 gallons at $3.00 per Gallon $18.00 per trip times 6 =$108.00 oh almost forgot it's a toll road so $7.00 per trip times 6 = $42.00
Time spent reclaiming batteries. That actually is an income stream for me as I would otherwise be spending money hanging out with my PhD friends at a bar and spending money. So let's call it a draw.
Testing equipment oh let's splurge and say $1000.00 on various meters, testers and such.
OK grand total investment is Drummroll please $2952.00
$2952.00 ÷ 2512 =$1.175 per cell.
2512 cells at $4.00 each = $10,048.00
Any Questions?
 Forgot to mention:
All cells that have a capacity of 1800mAhs to 2199mAhs will be for sale at some time so there will be a recouping of some of the cost.
Wolf
BlueSwordM, Korishan, Bubba And 2 others like this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
For Info Google Drive
Not your average Wolf       
            Cool



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#6
Adding a little more by someone who left school to start work at 15..... :-)

Your average $1.175 per cell (potentiall less deducting future 70-80% cells)

3.6V nominal and taking a 2200mAh nominal average capacity through the remaining cycle life you get 7.92Wh per cell

7.92W per cell and say 800 (100% equivalent - not full 0 to 100) cycles then you get 6.34kWh of cycle life per cell.

$1.175 per cell and 6.336Wh of cycle life give you a throughput energy cost of $0.185 per kWh....

That's excluding losses, so with losses you may be close to $0.20 per kWh to store energy into the cells and get (not as much) back out again....

Increase the cycle life to 1200 on a very sub 1C rate and then your closer to $0.1236 / kWh.
Wolf likes this post
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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