Patent ID: 8643331
Filing Date: 2014-02-04
Classification: G01R,H01M,Y02E

Abstract:
1. A method of improving performance of a battery fuel gauge comprising: providing a voltage based fuel gauge that monitors a terminal voltage of a battery and determining the battery's state of charge based on a battery model; providing a coulomb counter to provide a measure of current into and out of the battery; determining a first remaining charge in the battery using a product of a full capacity of the battery times the state of charge as determined by the voltage based fuel gauge; determining a second remaining charge in the battery using a combination of the first remaining charge in the battery and the current into and out of the battery as provided by the coulomb counter, the current into and out of the battery dominating the determination of the second remaining charge in the battery except during low or zero currents; and continually updating the second remaining charge by repeatedly subtracting a value responsive to the second remaining charge from the first remaining charge to repeatedly obtain an updated second remaining charge, the first remaining charge dominating the second remaining charge during low or zero currents.