A circuit module for coupling a plurality of battery cell units , the circuit module including a first set of terminals having a positive terminal and a negative terminal for coupling to a first battery cell unit , a second set of terminals having a positive terminal and a negative terminal for coupling to a second battery cell unit , a third set of terminals having a positive terminal and a negative terminal for coupling to a third battery cell unit , and a fourth set of terminals having a positive terminal and a negative terminal for coupling to a fourth battery cell unit , the positive terminal of the first set of terminals being coupled to the negative terminal of the second set of terminals either directly or via one or more passive components, the positive terminal of the third set of terminals being coupled to the negative terminal of the fourth set of terminals either directly or via one or more passive components, the negative terminal of the first set of terminals, the positive terminal of the second set of terminals, at least one of the terminals of the third set of terminals and at least one of the terminals of the fourth set of terminals each being coupled to a switching assembly, and wherein the switching assemblies are operatively configured to selectively connect or disconnect each one of the battery cell units , each switching assembly including one or more switching devices , each switching device operable in a conductive state and a non-conductive state, characterised in that the switching assemblies are operatively configured to selectively allow operating in a plurality of states in which any two or more battery cell units are connected in series, each state including a charging cycle and a discharging cycle of the battery cell units connected in series, the plurality of states including a first state in which the first battery cell unit and the second battery cell unit are electrically connected in series and the third battery cell unit is disconnected, a second state in which the first battery cell unit and the third battery cell unit are electrically connected in series and the second battery cell unit is disconnected, a third state in which the second battery cell unit and the third battery cell unit are electrically connected in series and the first battery cell unit is disconnected, a fourth state in which the first battery cell unit , the second battery cell unit and the fourth battery cell unit are electrically connected in series and the third battery cell unit is disconnected, and a fifth state in which the first battery cell unit , the second battery cell unit , the third battery cell unit and the fourth battery cell unit are electrically connected in series, and wherein the first battery cell unit , the second battery cell unit , the third battery cell unit and the fourth battery cell unit are adjacently positioned to one another such that the fifth state is achieved via a connection path having a minimum number of conducting switching devices within the circuit module , and wherein when the second battery cell unit and the third battery cell unit are connected in series, a series connection path between the second battery cell unit and the third battery cell unit includes a maximum of two switching devices operating in the conductive state. a first set of terminals having a positive terminal and a negative terminal for coupling to a first battery cell unit , a second set of terminals having a positive terminal and a negative terminal for coupling to a second battery cell unit , a third set of terminals having a positive terminal and a negative terminal for coupling to a third battery cell unit , and <EOS>