The invention discloses a flexible cell management system and belongs to the cell management and energy storage field. The flexible cell management system can realize flexible measurement, protection and management on cells of the cell groups, has low requirements for external voltages and can be directly connected with AC. The flexible cell management system comprises multiple cell management units connected in serial and in parallel, wherein each cell management unit comprises one or two cells and four or six switches, and can realize external port positive connection, reverse connection and bypass functions, and the switches can any type of diodes, triodes, relays, thyristors, silicon controlled rectifiers, MOS tubes and IGBTs and can also be combination of all the types above to form a bi-directional switch module or device. The flexible cell management system can be composed of multiple cell management units in series, in parallel, in series and then in parallel, in parallel and then in series, or in hybrid connection mode. The flexible cell management system has low requirements for external charging and discharging voltages and can even realize external AC charging and discharging, the flexible cell management system further improves reliability of the cell groups, and internal resistance can be easily and accurately measured.