Method and apparatus for estimating state of charge of secondary battery

Abstract

When a power switch portion 10 is in an open state and a charge / discharge path of the secondary battery 100 is in a disconnected state, an electromotive force calculation portion 109 calculates a battery electromotive force Veq by subtracting a polarized voltage Vpol stored in a polarized voltage storage portion 113 from an open-circuit voltage OCV measured by a voltage measurement portion 102. Based on the electromotive force, a state-of-charge estimation portion 110 estimates a state of charge SOC. Thus, a polarized voltage to be considered for the estimation of SOC can be limited. The state of charge (SOC) of a secondary battery can be estimated with high accuracy and quickly.

Description

technical field

[0001] The present invention relates to a method of estimating the state of charge (SOC) of a secondary battery, such as a nickel metal hydride (Ni-MH) battery, etc., wherein the secondary battery is installed in a pure electric vehicle (PEV), a hybrid electric vehicle (HEV), etc., as a power source for motors and a drive source for various loads. Background technique

[0002] Traditionally, in HEVs, when the output of its engine is higher than the power required for driving, the remaining power drives the generator to charge the secondary battery. Conversely, when the output of the engine is lower than the required power, the electric power of the secondary battery will drive the motor to output power so as to make up for the shortage of required power. In this case, the secondary battery is discharged. Therefore, when a secondary battery is mounted on an HEV or the like, it is necessary to control charging and discharging of the secondary battery to maint...

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