Patent ID: 9494656
Filing Date: 2016-11-15
CPC Classification: G01R

Claim Text:
1. A system for determining the state of charge (SOC) of a lithium battery comprising: a controller measuring an initial open circuit voltage (OCV) at a first time; the controller determining the SOC of the battery from the measurement of the OCV at the first time; a power source charging the battery at a predetermined DC current; the controller determining a subsequent SOC of the battery at a second time based on charging current and the amount of time the battery is being charged; the controller utilizing the subsequent SOC of the battery to determine a subsequent OCV of the battery; the controller utilizing the subsequent OCV to determine a corresponding impedance of the battery; a memory coupled to the controller for storing correspondence between an impedance of the battery and corresponding SOC of the battery; and the controller, during a discharge time, utilizing the correspondence of the SOC of the battery and the impedance of the battery, which was determined during battery charging, to determine a discharge SOC by determining the present impedance of the battery through measurement or prediction.