Battery health state detection method and device

Abstract

The invention relates to the field of battery detection, and discloses a battery health state detection method. The method is characterized in that the method comprises the steps: measuring a voltage value U1 and a charging current I of a battery when the battery is in a state of charging; switching the charging state of the battery to a switching-off state, and measuring a voltage value U2 of the battery after switching-off; determining the internal resistance value Rn of the battery according to the difference between the voltage value U1 and the voltage value U2 and the charging current I; comparing the internal resistance Rn with an internal resistance-health state corresponding table provided by a battery manufacturer, and determining the corresponding health state of the battery.

Description

technical field [0001] The invention relates to battery detection, in particular to a method and device for battery health state detection. Background technique [0002] The internal resistance is an important parameter of the lithium battery, which directly determines the available power of the lithium battery pack and affects the power of the electric vehicle. At the same time, the internal resistance also reflects the state of health of the lithium battery (State-of-Health, SOH), compared with when the battery just leaves the factory, as the number of cycles of the battery increases, the internal resistance of the battery will gradually increase due to the decrease in the activity of the chemical substances inside the battery and the aging of the electrode material. Therefore, the internal resistance change is also One of the ways to estimate the state of health of lithium batteries. [0003] Since the internal resistance of lithium batteries is small and changes slowly,...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the delay problem existing in the prior art when measuring the battery terminal voltage and current, which leads to large errors in the online measurement of the internal resistance of the battery, which in turn affects the prediction of the battery’s health status, and provides a A method and device for battery health state detection, the method has the function of detecting the voltage value U in the charging state of the battery 1 and the voltage value U after disconnecting the charge 2 and the charging current I, and prolong the detection time of the battery terminal voltage, that is, set two time points t respectively 1 and t 2 Detect the voltage value U of the battery charging state respectively 1 and the voltage value U after disconnecting the charge 2 , the set time Δt between the two time points is used to wait for the battery terminal voltage to be stable, and to perform the above detection at the set temperature and battery charging state, according to the voltage value U 1 with the voltage value U 2 The difference between and the charging current I, determine the internal resistance value R of the battery n , also the internal resistance value R n with the last internal resistance value R n-1 For comparison, when the comparison difference is not greater than the preset difference, the internal resistance value R n It is updated to the internal resistance value of the battery; the device completes the detection and updating of the internal resistance of the battery through the detection unit and the control unit through the above method; and then according to the updated internal resistance value of the battery and the internal resistance provided by the battery manufacturer - The health state corresponding table is compared, the corresponding health state of the battery is determined according to the comparison result, and the updated battery internal resistance value is corrected according to the measurement result, and then the health state of the battery is corrected

Images