BQ40Z50: BQ40Z50R2 Cell balancing working algorithm

Slim123

Part Number: BQ40Z50
Other Parts Discussed in Thread: BQSTUDIO

Hi,

For battery with 4 cells on bq40z50r2, how does the fast cell balancing works?

For example, if cell 2 voltage is highest and cell 1 is the lowest, which FET will be opened or closed to balance cell 1 and 2 ?

Also we are seeing balancing is running on and off because CB status flag will toggle after certain interval although battery is not balanced yet. Is this normal?

Thanks

over 7 years ago

0 Swaminathan Ramanathan75031 over 7 years ago

TI__Expert 6575 points

The cell balancing in bq40z50-R2 is based on capacity and not Voltage. So for example if Capacity of Cell2 is the highest capacity, then Q207 will be turned on during charging or rest (If Cell balancing in Rest is turned on and RSOC > Min RSOC for Balancing) for the amount of time calculated by the gauge. You can see the balancing timer for each cell in the registers screen in bqStudio.
Regards,
Swami

0 Slim123 over 7 years ago in reply to Swaminathan Ramanathan75031

Expert 1210 points

Hi Swami,

I notice sometimes BAL_EN will be off after it is doing balancing for awhile. What determines BAL_EN to be ON or OFF?

Thanks

0 Slim123 over 7 years ago in reply to Swaminathan Ramanathan75031

Expert 1210 points

Hi,

When pack is discharging, does it allow the packs to do balancing?

Thanks

Power management

Power management forum

BQ40Z50: BQ40Z50R2 Cell balancing working algorithm