BQ76922: Balancing current

Vladislav Mocluza

Part Number: BQ76922

Tool/software:

Hello,

I am designing a battery pack with LiFePO4 cells with external passive balancing.

Do you have any recommendations about amount of balancing current?

I see somewhere in Internet recommendations about 0.5% - 2% from charge current, but it is still not clear how to define this value.

Best regards,

Vladislav

0 Vladislav Mocluza 5 months ago

What is wrong with this question?

No answers yet.

0 Kian Lin 5 months ago in reply to Vladislav Mocluza

Hi Vladislav,

It should depend on your cell capacity and how long you want to balance the battery cell.

For example, if you want to balance 5% SOC of 25Ah cell in 10 hr. You need 25*5%/10=125mA.

BQ76922 can support 100mA max internal balancing current so you need add external BJT balancing circuit to achieve higher balancing current.

BRs

Kian

0 Vladislav Mocluza 5 months ago in reply to Kian Lin

Hi Kian,

Sounds like these calculations are for balancing after charge termination,

But are there any recommendations about balancing during charging?

0 Kian Lin 5 months ago in reply to Vladislav Mocluza

Hi Vladislav,

The calculation is same. It changes with your requirement. Can you imagine the worst case during charging and calculate it with the same formula?

BRs

Kian

Power management forum