System and method for on-line dynamic measurement of electric quantity of lithium ion batteries

Abstract

The invention provides a system for measuring the electric quantity of lithium ion batteries. The system is used for on-line dynamic measurement and correction of the electric quantity of the lithium ion batteries at work to reduce measuring errors. The system for measuring the electric quantity of the lithium ion batteries is characterized by comprising a voltage and current acquisition module, a temperature acquisition module, a processing module, a display module and a voltage stabilizing circuit. The voltage and current acquisition module is used for acquiring terminal voltage and main line current data of N storage battery sets at the same time point and transmitting the terminal voltage and main line current data to the processing module; the processing module conducts least squares fit on the terminal voltage and main line current data, a U-I curve is obtained, and the electromotive force epsilon and the internal resistance r of the lithium ion batteries are obtained through calculation; internal temperature data of the lithium ion batteries are acquired at regular time; the state of charge of the lithium ion batteries is obtained in a partition linear processing mode according to the electromotive force epsilon of the lithium ion batteries; burn-in correction and temperature correction are conducted on the state of charge respectively in a partition linear processing mode according to the internal resistance r and internal temperature T of the lithium ion batteries, and therefore real-time data of the electric quantity of the lithium ion batteries at the time point are obtained.

Description

technical field [0001] The invention relates to a system and method for on-line dynamic measurement of lithium-ion storage battery power. Background technique [0002] With the widespread application of lithium-ion batteries, the on-line dynamic measurement of their power is becoming more and more important. The traditional power measurement technology is mainly based on the measurement of open-end voltage (OCV), which has obvious limitations in measurement performance. First of all, the scheme based on the measurement of the opening voltage cannot be dynamically measured online, and it will be affected by the change of the internal resistance of the battery over time; at the same time, due to the chemical characteristics of the lithium-ion battery, within a certain range, the higher the temperature, the higher the temperature. The higher the activity, the more electricity can be released, and vice versa. Dynamic load conditions and temperature changes can cause errors in ...

AI Technical Summary

Problems solved by technology

First of all, the scheme based on the measurement of the opening voltage cannot be dynamically measured online, and it will be affected by the change of the internal resistance of the battery over time; at the same time, due to the chemical characteristics of the lithium-ion battery, within a certain range, the higher the temperature, the higher the temperature. The higher the activity, the more electricity can be released, and vice versa

Dynamic load conditions and temperature changes can cause errors in measurements of up to 50%

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