The way you drew it, works for 6 cell battery. That too, if the max input voltage of ADC= 6 X cell voltage. But in reality, even for 12 volts you need to bring it down to 2.5 volts or 5 volts max span of ADC voltage. So you need resistors to bring it down. Now if you have 3 batteries, then you need more. If you have a 360 volts battery system, then you need to tap each cell point, bring the voltage down and calibrate it using either a pot or software. You can't avoid resistors.

In flying cap, you don't need these, but you need to switch 2 wires per sample. Switch needs to be able to handle maximum of cell voltage (am I not wrong?). In this case, If I have 360 volts battery, and if I am measuring the cell voltage of the topmost cell, I can use a two normal swtiches,charge my charge-sampler capacitor, disconnect the switch and connect the capacitor to my ADC. IE: I can even use an analog switch for connecting to the cell asl long as I have an isolated supply for that analog switch. Right?

Raj Nambiar