Cell balancing system for Lithium battery using low battery voltage and charging method by low battery voltage using that of

摘要

The present invention relates to a lithium battery cell balancing system using a low-voltage battery, and a low-voltage battery charging method using a cell balancing current. The voltage of each of tens or hundreds of lithium batteries connected in series is measured. Switches are connected to a (+) pole and a (-) pole of each lithium battery to connect the current of lithium batteries having a high voltage to a supercapacitor connected to each lithium battery in parallel, and store the current. The plurality of connected supercapacitors are connected in series, and (+) and (-) switches of each cell are connected or disconnected from the super capacitors and switches connected in parallel by (+) and (-) circuits in the order of cells, of the plurality of lithium batteries connected in series, having a high voltage measured from the cells so that low-voltage batteries are charged with the current. The configuration is applied to a super capacitor and a battery system for an electric car for energy saving. Thus, when the voltages of the plurality of battery cells connected in series in order to generate a high voltage are different from each other, the low-voltage batteries (12 V or 24 V) can be charged by moving current from the cells having a high voltage to the super capacitor. In contrast, battery cells having a low voltage among the plurality of lithium battery cells connected in series can be charged by moving current from the charged low-voltage batteries to the super capacitor. As a result, selective charging can be achieved.