Estimated balance minutes

[Jonndeka]

I was looking for cell balancing time and I saw the following formula from here.
But I didn't figure out what's the unit of ocv slope. Is it a factor without unit or degree ...?

CHARGE WITH CB: in this state the cell balancing (CB) function will be activated. This function will calculate the estimated cell balance minutes per cell, which is based on the cell voltages, the difference compared to the lowest cell voltage, the balance resistor and the ocv-slope. The formula to calculate this estimated balance time is:

Estimated balance minutes = (Vcell - Vcell_min ) * Rbal / (Vcell * ocvslope)

Other than this calculated time, the BMS will check if the voltage of a cell that is being balanced, has reached the desired voltage as well. When the voltage of one of the cells reaches the cell overvoltage level or the charging current is less than the charge complete current, it will go to the RELAXATION state. The LED will stay blue and will blink if cell balancing is active.
Balancing is finished if all the calculated cell balance minutes are expired or it has reached the lowest cell voltage.

 

[Jonndeka]

Anybody doesn't have any comment?

 

[fechter]

I assume it would be volts/minute. It's going to depend on the actual circuit used, but I have to assume it's a typical bleeder resistor across the cell.

 

[Jonndeka]

I assume it would be volts/minute. It's going to depend on the actual circuit used, but I have to assume it's a typical bleeder resistor across the cell.

Do you think can we say: Slope of OCV = dOCV/dSOC ?

 

[fechter]

That's what I would guess. The actual slope is not a straight line, but as an approximation it is probably good enough.

 

[Jonndeka]

That's what I would guess. The actual slope is not a straight line, but as an approximation it is probably good enough.

Yes. This is just an example for my understanding, but for accurate slope we need to consider a short time interval.
But as you mentioned, the unit of this slop is volts/minute, but in this derivative we don't have consider time directly.