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Spec sheet?
BMS information
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MOSFET model:
MOSFET number:
BMS IC:
BMS schematic?
BMS protocol?
Batch information
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2nd Life information
Process
Ranking
90-91 | C10R1 | C10R2 | C10R3 | C10R4 | C10R5 |
91-92 | C9R1 | C9R2 | C9R3 | C9R4 | C9R5 |
92-93 | C8R1 | C8R2 | C8R3 | C8R4 | C8R5 |
93-94 | C7R1 | C7R2 | C7R3 | C7R4 | C7R5 |
94-95 | C6R1 | C6R2 | C6R3 | C6R4 | C6R5 |
95-96 | C5R1 | C5R2 | C5R3 | C5R4 | C5R5 |
96-97 | C4R1 | C4R2 | C4R3 | C4R4 | C4R5 |
97-98 | C3R1 | C3R2 | C3R3 | C3R4 | C3R5 |
98-99 | C2R1 | C2R2 | C2R3 | C2R4 | C2R5 |
>99% | C1R1 | C1R2 | C1R3 | C1R4 | C1R5 |
SOH / IR 3.6V | 22-25.5 | 25.5-26 | 26-26.5 | 26.5-27 | 27-28 |
Statistics
Cell counting spreadsheet
Link to statistics sheet for TESTED CELL COUNTING:
Journal
06/02/23 - Cells from Elemoove reception, first PRETEST
We received cleaned up cells from Elemoove
Problems:
- Some cells are cut on the periphery. Extremely dangerous
0V, 0.3V, 0.4V on the punctured cells
2.24V 27mR on the cell crushed but not punctured
- Most cells are badly cleaned up
PRETEST program for B2 batch:
Results on 85 cells:
We put ~400 cells on Mireille
08/02/23 - Chantal capacity statistics
256 cells from SLOT1 were put on Chantal for a DC1_CHA mesurement
1 cell at 3070
Need to cycle a few NEW BD cells on Chantal to get 100% SOH capacity DC1_CHA
Datasheet (no precision on @ what discharge current):
Based on 3070:
10/02/23 - New cell capacity on Chantal
- 12% cells are between 2 and 2.2V
- 14.5% cells with a valid voltage are between 27 and 29mOhm
⇒ We could be less strict
We put 256 cells on Chantal. The 3 first cells are new BD cells from Nkon
⇒ 3130mAh is the DC1_CHA capacity of new BD cells, it will be used as a reference for 100% SOH
See cap categories here: https://docs.google.com/spreadsheets/d/1UKBXvYpqJI9ptoyBCIY99lIp26wOwSHP9paZGlLRGgs/edit#gid=0
13/02/23 - Bad cell self-discharge
One cell at 2.17V after Chantal:
It is a bent cell:
What happened when it went on Chantal?
Surprisingly its impedance is OK!
Je pense que lors du PRETEST elle était > 2.2V, et que le temps de la passer sur Chantal elle est passée en dessous à cause d'une autodécharge élevée, sûrement due à une autodécharge forte à cause de micro court-circuits internes vu qu'elle est tordue
Check bent cell. Self-discharge? What happens if I precharge slowly? It was a 2.17
Up the PRETEST limit to 28mOhm. Bad cells will be discarded after voltage equalization on Chantal
Take the cells down to 2.0V?
If so, change program on Chantal to precharge at low current until at least 2.5V. Add a timetout?
Je pense qu'il faut qu'on ajoute une première étape de précharge lente jusqu'à peut-être 3V ou +, avec un timeout. Comme ça si une cellule monte pas en tension (court-circuits) elle s'arrête
Put again the cells from SLOTs 5 and 7 in the machine
15/02/23 - PRETEST acceptance increase and TEST IMPEDANCE parameters
More PRETEST stats:
- About 52% “good” cells (2.0~4.2V, 27~29mOhm), 48% “bad” cells (others)
- 14% 0~2.0V
- 11% 2.0~2.2V (0~29mOhm)
- 5% >29mOhm
- 16% 27~29mOhm (>2.2V)
The 2.0~2.2V and 27~29mOhm (11% and 16%) cells went again through Mireille with the new parameters (take cells down to 2.0V and up to 28mOhm):
⇒ We regain 77% of the previously discarded cells 2.0V~2.2V and 27~29 (11% and 16%)
⇒ 0.52 + 0.77 * (0.11 + 0.16) = 73% “good” cells instead of 52%
Impedance of 3x new BD cells:
Is the measurement repeatable?
4x the same 3 cells:
⇒ Voltage measurement is VERY accurate
3.6081: 23.8, 23.6, 23.0, 22.7
3.6105: 24.1, 23.7, 23.7, 23.6
3.6098: 24.4, 24.2, 24.4, 24.0
It looks like the measurement current “wakes up” the cell a bit, because the impedance value decreases at each measurement
Test Impedance parameters selection
Results from IMPEDANCE_TEST on voltage equalized cells?
Test IR on voltage-equalized cells :
New cells are 23~24mOhm
Almost none (< 0.1%) of the tested cells from Dott were in this category
- 0.7% <24mOhm
- 3% 24~25mOhm
- 25% 25~26mOhm
- 55% 26~27mOhm
- 14% 27~28mOhm (there will be more in this category since we now also take the 27~28mOhm cells during PRETEST)
- 0.2% >28mOhm (there will be more here too)
Proposition:
R1 | < 25 |
R2 | 25~26 |
R3 | 26~26.5 |
R4 | 26.5~27 |
R5 | 27~28 |
Test with cells from C5:
⇒ Not well distributed
New proposition:
R1 | 22~25.5 |
R2 | 25.5~26 |
R3 | 26~26.5 |
R4 | 26.5~27 |
R5 | 27~28 |
New try with the same cells:
⇒ Good !
Here are the final resistance categories:
Rx | Range | Distribution (approx) |
R1 | 22~25.5 | 33% |
R2 | 25.5~26 | 35% |
R3 | 26~26.5 | 22% |
R4 | 26.5~27 | 9% |
R5 | 27~28 | 1% |
Program name: B2_TEST_IMPEDANCE
16/02/23
Précharge lente 300 mA :
Ici la cellule se restabilisait peut-être vers 2.7V, donc elle est repassé à 3V en 3min30. A voir combien de temps si on part de 2V vraiment.
Programme pour mieux descendre vers les 2V :
Relancé sur 3-8 (BD)
02/03/23
73.6% reusable cells. Estimation was spot on
Todo
Calib Chantal?