Battery health degree detection method and device

Abstract

The invention relates to a battery health degree detection method and device. The method comprises the following detection steps of S1, carrying out the constant-current discharge test of N sample batteries of the same type as a to-be-detected battery, and obtaining N groups of voltage time sequence data urr1, urr2... urrN; S2, constructing an independently applicable time normalization formula for each group of voltage time sequence data; S3, performing time normalization on the N groups of voltage time sequence data according to the time normalization formula, and drawing a point set graph according to the N groups of voltage time sequence data after time normalization to obtain a convergence track; S4, performing data fitting on the convergence trajectory to obtain a time normalization standard curve L, and recording the voltage value range of the time normalization standard curve L as [UA, UB]; S5, performing constant-current discharge on the to-be-tested battery to obtain related parameters of the to-be-tested battery; and S6, judging the health degree of the to-be-detected battery according to the time normalization standard curve L and the related parameters of the to-be-detected battery.

Description

technical field [0001] The invention relates to the technical field of battery health degree detection, in particular to a battery health degree detection method and device. Background technique [0002] Battery health SOH refers to the ratio of the released capacity of the battery from the full state to the cut-off voltage at a certain rate under standard conditions and the corresponding nominal capacity, that is, SOH=actual capacity of the battery / nominal capacity of the battery. The SOH of the battery reflects the degree of battery deterioration. In order to obtain the SOH of the battery, the actual capacity of the battery should be tested or estimated. At present, the only recognized reliable method in the industry to test the actual capacity of the battery is the direct discharge method, that is, to use the load to actually discharge the battery once and measure the actual discharge capacity. However, the direct discharge method consumes a lot of time, manpower and fin...

AI Technical Summary

Problems solved by technology

At present, the only recognized reliable method in the industry to test the actual capacity of the battery is the direct discharge method, that is, to use the load to actually discharge the battery once and measure the actual discharge capacity. However, the direct discharge method consumes a lot of time, manpower and financial resources, and is often not suitable for actual use. Therefore, the industry has developed many testing or estimation methods that can replace the direct discharge method, such as internal resistance method, electrochemical impedance analysis method, Erin equation model method, etc.

The Chinese invention patent application with the publication number CN108427076A discloses a power battery SOH estimation method. By normalizing the UT data of the charging and discharging process under different discharge rates and different aging degrees, the normalized battery is obtained. The change curve of voltage and SOC is used to estimate the SOH value of the battery, and the accuracy of SOH estimation is improved through averaging processing, which realizes both versatility and accuracy. However, this estimation method needs to collect the charge and discharge. The UT data of the process greatly increases the test time and increases the test cost

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