Patent ID: 9720045
Date: 2017-08-01
CPC Classifications: G01R,H01M,Y02E

Claim:
1. An apparatus for estimating a state of charge (SOC) of a secondary battery, which includes a cathode having a blended cathode material containing a first cathode material and a second cathode material with different operating voltage ranges, an anode having an anode material, and a separator for separating the cathode from the anode, the apparatus comprising: a sensor configured to measure a discharge inception voltage and a final discharge voltage when the secondary battery is discharged for a predetermined time; and a control unit configured to estimate a SOC of the secondary battery corresponding to the measured discharge inception voltage and the measured final discharge voltage by using a predetermined relationship between the discharge inception voltage and the final discharge voltage and the SOC of the secondary battery, wherein the discharge inception voltage is a key-on voltage measured right after the secondary battery in a no-load state comes to a key-on state, and wherein the final discharge voltage is a key-on discharge voltage measured after the secondary battery in the key-on state performs key-on discharge for a predetermined time.