A battery pack comprising: - a first battery cell and a first group of battery cells; - a controller arranged to control charging and discharging operations of the first battery cell; - an analog switch arranged to detect a voltage value corresponding to the first battery cell and to transfer data of the detected voltage value to the controller, the analog switch including a flying capacitor (Cf) arranged to store the voltage value corresponding to the first battery cell, wherein the analog switch comprises: a first transistor having a first electrode connected to a first battery terminal of the first battery cell, and a second electrode connected to a first terminal of the flying capacitor, the first transistor being controlled according to a first signal from the controller; a first diode comprising an anode connected to a second battery terminal of the first battery cell and a cathode connected to a second terminal of the flying capacitor; a second transistor having a first electrode connected to the first terminal of the flying capacitor, and a second electrode coupled to the controller, the second transistor being controlled according to a second signal from the controller; and a second diode comprising an anode connected to a first voltage supply, and a cathode connected to the second terminal of the flying capacitor; - a voltage sensing and balancing circuit comprising a number of input terminals equal to the number of cells in the first group of battery cells, each of the input terminals coupled to one of the cells in the first group of battery cells, the voltage sensing and balancing circuit being arranged to sense voltages of each of the cells in first group and to provide data of voltages detected from each of the cells in the first group of battery cells to the controller. - a first battery cell and a first group of battery cells; - a controller arranged to control charging and discharging operations of the first battery cell; - an analog switch arranged to detect a voltage value corresponding to the first battery cell and to transfer data of the detected voltage value to the controller, the analog switch including a flying capacitor (Cf) arranged to store the voltage value corresponding to the first battery cell, wherein the analog switch comprises: a first transistor having a first electrode connected to a first battery terminal of the first battery cell, and a second electrode connected to a first terminal of the flying capacitor, the first transistor being controlled according to a first signal from the controller; a first diode comprising an anode connected to a second battery terminal of the first battery cell and a cathode connected to a second terminal of the flying capacitor; a second transistor having a first electrode connected to the first terminal of the flying capacitor, and a second electrode coupled to the controller, the second transistor being controlled according to a second signal from the controller; and a second diode comprising an anode connected to a first voltage supply, and a cathode connected to the second terminal of the flying capacitor; a first transistor having a first electrode connected to a first battery terminal of the first battery cell, and a second electrode connected to a first terminal of the flying capacitor, the first transistor being controlled according to a first signal from the controller; a first diode comprising an anode connected to a second battery terminal of the first battery cell and a cathode connected to a second terminal of the flying capacitor; a second transistor having a first electrode connected to the first terminal of the flying capacitor, and a second electrode coupled to the controller, the second transistor being controlled according to a second signal from the controller; and a second diode comprising an anode connected to a first voltage supply, and a cathode connected to the second terminal of the flying capacitor; - a voltage sensing and balancing circuit comprising a number of input terminals equal to the number of cells in the first group of battery cells, each of the input terminals coupled to one of the cells in the first group of battery cells, the voltage sensing and balancing circuit being arranged to sense voltages of each of the cells in first group and to provide data of voltages detected from each of the cells in the first group of battery cells to the controller.