Multi-string lithium battery voltage detection circuit based on mirror current source

Abstract

The invention relates to a multi-string lithium battery voltage detection circuit, in particular to a multi-string lithium battery voltage detection circuit based on a mirror current source. The multi-string lithium battery voltage detection circuit based on the mirror current source comprises multiple voltage detection modules, a voltage sampling module and a control module, wherein each voltage detection module is arranged at both positive and negative poles of each lithium battery; a signal input end of each voltage detection module is connected with a signal output end of the control module, and a signal output end of the voltage detection module is connected with a signal input end of the voltage sampling module. According to the multi-string lithium battery voltage detection circuit based on the mirror current source, high-voltage signals of multi-string batteries can be converted into low-voltage signals for BMS (battery management system) detection, multi-string battery voltage sampling with low cost and high precision is realized, besides, reliability and maintainability of the circuit are high, and if a voltage detection cable is wrongly connected, circuit damage can be effectively prevented due to the facts that three triodes are arranged in each voltage detection module and have the voltage withstanding characteristic.

Description

technical field [0001] The invention relates to a multi-string lithium battery voltage detection circuit, in particular to a multi-string lithium battery voltage detection circuit based on a mirror current source. Background technique [0002] At present, electric vehicles use multiple lithium batteries in series as power. The series voltage of electric vehicle power lithium batteries is usually as high as 300V~400V, and the voltage range of each lithium battery is 2.5V~3.9V, so the power battery needs more than 100 series batteries. BMS (Electric vehicle battery management system) is an important link connecting the on-board power lithium battery and electric vehicle. Its most important function includes real-time monitoring of the lithium battery voltage. During the charging and discharging process of the lithium battery, the BMS collects the real-time The voltage of each string of lithium batteries prevents overcharging or overdischarging of lithium batteries. [0003] I...

AI Technical Summary

Problems solved by technology

[0003] In the existing technology, integrated chips provided by some manufacturers or a matrix composed of multiple high-performance optocouplers are usually used to detect the voltage of multiple strings of lithium batteries, but the number of battery strings detected by each chip is small, and more than 100 strings Battery detection usually requires multiple chips, so the detection cost is extremely high. At the same time, if the voltage detection wiring is wrongly connected, the chip will be burned, so the reliability and maintainability are poor.

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