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BQ25910: charging / discharging 3x 2P battery packs in parallel

Part Number: BQ25910
Other Parts Discussed in Thread: BQ25306

Hello,

we are facing the challenge to use 3x 2p battery packs in parallel to extend the battery capacity. Each 2P LiIon pack has 5200mAh capacity and 2500mA max charging current. The packs will be mounted into a device permanently. The approach shall be used to extend the battery capacity of the end device by using multiple off the shelf battery packs.

Each pack has it's own NTC. Further It can not be confirmed that the pack will be at the same state of charge when mounted into the device. The customer would buy the pack and mount it, ideally without further testing or charging.

The application could charge and discharge all the cells in parallel at the same time using a device like the BQ25910. Vin will be 12V. Output is regulated down to 3,3V. In this case we have to take care about the same state of charge when mounting the battery pack into the device. However, we still will have individual NTCs to deal with.

Alternatively a muxing scheme could be used charging and discharging each cell at a time to extend the operating time of the system (TDM), the discharge current with 2A of one pack will be enough to power the application. In this case a muxing an power path scheme will be needed.

3rd option is to have individual charges per pack and a o-ring circuit at the output

What would be your recommendation how to approach this?

many thanks

Lutz