Circuit and method for measuring internal resistance of single battery in power battery box

Abstract

The invention discloses a circuit for measuring the internal resistance of a single battery in a power battery box. The measurement circuit comprises an AC excitation circuit, an AC voltage sampling circuit and a main control circuit. The AC excitation circuit inputs alternating-current excitation to the single battery; the AC voltage sampling circuit is used for detecting an alternating-current voltage response signal of the single battery under the action of alternating-current excitation; the output end of the AC voltage sampling circuit is connected with the main control circuit; and the main control circuit calculates resistance data of the single battery according to alternating-current excitation current and collected alternating-current voltage. According to the invention, the internal resistance data of each single battery in the battery box can be automatically detected, and data support is provided for the work of a battery management system; the circuit for measuring the internal resistance of the single battery is simple and reliable in structure and less in hardware improvement, and can be conveniently integrated in the battery management system or the battery box soas to facilitate realization of online detection.

Description

technical field [0001] The invention relates to the field of battery management, in particular to a circuit for measuring the internal resistance of battery cells in a power battery box. Background technique [0002] In new energy vehicles, BMS, as an important component, mainly monitors the state parameters of the power battery, and provides charge and discharge management control, battery maintenance and external communication functions according to the requirements of the vehicle. [0003] At present, the BMS on the market mainly monitors the battery data including the total voltage of the battery box, the total current, the voltage of the single battery, the temperature of the battery box, and the insulation detection between the battery box and the car, but lacks the function of measuring the resistance of the single battery. For the resistance measurement of the power lithium battery, at present, it is mainly measured manually using a dedicated battery resistance measu...

AI Technical Summary

Problems solved by technology

[0003] At present, the BMS on the market mainly monitors the battery data including the total voltage of the battery box, the total current, the voltage of the single battery, the temperature of the battery box, and the insulation detection between the battery box and the car, but it lacks the measurement function of the resistance of the single battery.

For the resistance measurement of the power lithium battery, at present, it is mainly measured manually using a dedicated battery resistance measuring instrument. This method cannot measure the battery in the car and must be unpacked, which leads to the actual operation of measuring the battery resistance. The increase in time and cost is something that car companies and consumers do not want to see, so it is particularly important to add the automatic measurement function of battery resistance to BMS

Images