BQ76930: What's cells configuration recommend for 17S application?

Hi Che,
Two important operating conditions for the bq76930 are 1) to keep VC5X above VSHUT in short circuit/heavy load conditions, and 2) keep sufficient REGSRC voltage for the FET drives.
I would recommend configuration 2 since if you are using a circuit like TIDA-01093, keeping the voltage split approximately equal between the devices should give good operating voltage for each, and since having fewer cells on the top group of the lower device should reduce the load on the VC5X during short circuit. Your specific circuit may have special considerations, use simulation as needed to assist with analysis, and be sure to test your solution.