Battery management system and operating method thereof

The invention relates to a battery management system. The battery management system comprises a storage part, a first SOC speculative computation part, a SOH speculative computation part and a second SOC speculative computation part. The storage part is used for saving inputted voltage and current and saving OCV data mapping within the specified OCV range in accordance with SOC. The first ISOC speculative computation part is used for speculating a first SOC value by utilization of OCV data mapping in accordance with SOC on the condition that the current value is less than the critical current intensity and the voltage value exists in the pre-set specified range. The SOH speculative computation part is used for determining the condition that charging operation is performed by constant current and computing the battery speculative capacity in accordance with quantity of electric charge of the SOC rate of change and comparing speculative SOH value with the initial battery capacity. The second speculative computation part is saved on following conditions such as voltage value of a storage part out of the range of special voltage or current value of the storage part above the critical value. A second SOC value is speculated by utilization of accumulation of current value of battery speculative capacity. Speculation, computation, correction and hamming are carried out by means of two SOC ranges in order to reduce necessary time and cost.