Method and system for detecting single electrode potential of battery

Abstract

The invention discloses a method for detecting single electrode potential of a battery. The method comprises the following steps: an AC impedance test is used for acquiring AC impedance spectrums of a positive electrode / negative electrode, a positive electrode / reference electrode and a negative electrode / reference electrode of the battery in different states of charge (SOC) and at different temperatures; an equivalent circuit, a positive electrode equivalent circuit and a negative electrode equivalent circuit of the total battery are respectively used to fit the AC impedance spectrums of the positive electrode / negative electrode, the positive electrode / reference electrode and the negative electrode / reference electrode, and a related three-dimensional mapping table between equivalent impedance of the positive electrode and the negative electrode and the SOC and the temperature is obtained; the current electrode equilibrium potential is obtained according to the SOC of the battery and a equilibrium potential curve; and the single electrode potential is obtained according to the electrode equilibrium potential, charging / discharging current sum of the battery and the three-dimensional mapping table. The electrode potential of a common battery can be directly and conveniently measured, and accuracy of the measurement result is improved. The invention also provides a system for detecting single electrode potential of a battery.

Description

Technical field [0001] The invention relates to the technical field of battery management, in particular to a method and system for detecting the single electrode potential of a battery. Background technique [0002] In the field of electrochemistry and battery research, electrode potential is a very important parameter. The electrode potential in the thermodynamic equilibrium state is the open circuit potential. In practical applications, the voltage-SOC curve obtained by charging and discharging with a small current can be approximately regarded as the open circuit voltage curve of the battery. If the current density flowing through the electrode is large, the curve obtained is the terminal voltage curve. By observing the relative potential curve of a single electrode, the reaction information inside the electrode can be obtained. For example, for lithium ion batteries with graphite negative electrodes, overcharging or low-temperature charging may cause the side reaction of l...

AI Technical Summary

Problems solved by technology

The disadvantage of the three-electrode system is that it can only be studied in the laboratory, and the packaged battery cannot be tested directly.

However, this method is only suitable for the research of nickel-based aqueous batteries, and the main problem to overcome is the difficulty of sealing

It can be seen that the improvement of the above technical solution is still based on the three-electrode system, which cannot overcome the inherent shortcomings of this method for measuring single-electrode potential

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