Single chip voltage monitor for vehicle fuel cell stack

Abstract

Monitoring device is composed of resistance divider circuit, multiway switch circuit, difference operational amplification circuit, A/D conversion circuit, single chip and CAN communication circuit connected in sequence and communication interface to main controller of fuel cell. The device is capable of monitoring voltages of 59 single cells in fuel cell pile. Combining multiple disclosed monitoring devices with communication between main controller and each equipment realized through CAN network can monitor more cells. Features are: small size, low cost, easy of expansion, high measuring accuracy (maximum absolute error less than 0.08V) and quick measuring speed (time for measuring 59 single cell is less than 0.05 second).

Description

technical field [0001] The invention belongs to a fuel cell voltage monitoring device, in particular to a vehicle fuel cell stack monolithic voltage monitoring device. Background technique [0002] The fuel cell stack is composed of multiple single cells in series, and the operating voltage of a single cell is generally less than 1V. When the stack is working, it is necessary to measure the voltage of its single cell to achieve the purpose of monitoring the working state of the stack and protecting the fuel cell. [0003] The difficulty faced by the single-chip voltage measurement of the fuel cell stack used in vehicles is firstly the increase in the withstand voltage requirements of the electronic devices due to the potential accumulation of the single cell. For example, the number of single-chip batteries in a fuel cell stack for driving an electric bus reaches more than 600 pieces, and the output voltage of a fuel cell stack composed of 100 single-cell batteries can reac...

AI Technical Summary

Problems solved by technology

[0008] At present, most of the fuel cell stack single-chip voltage monitoring devices used in China are designed for non-mobile fuel cell stack voltage monitoring, and do not take into account the requirements of vehicle working conditions. There are certain deficiencies in monitoring, such as: the method of applying linear isolation differential operational amplifier requires each single cell to be equipped with an isolation operational amplifier, the system cost is high, the volume is large, and the wiring is complicated; All are equipped with a photoelectric isolation relay, which greatly increases the cost; moreover, the usual serial port communication method cannot meet the needs of vehicle system communication

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