Battey Safety Monitoring System Based On Fibre Optic Sensing Technology

Batteries are a widely used energy drive system in a variety of industries and are widely used in energy storage plants and military applications due to their excellent energy density,reliable cycling performance and long life.In recent years,safety issues such as fires and explosions caused by improper battery monitoring have become increasingly serious and have even resulted in casualties,hence the need to accurately monitor the health status of batteries in real time.With the development of optical fibre technology,optical fibre sensing technology as a new application technology,in many areas of rapid development.Optical fibre sensors are widely used in major projects for safety monitoring due to their small size,simple structure,low invasiveness,acid and alkali resistance,resistance to electromagnetic interference,good radiation resistance and the ability to achieve real-time online monitoring.In battery safety monitoring,fibre optic sensing technology not only enables long time real-time online monitoring,but also helps to improve the accuracy of monitoring,the technology has great potential for application.In this thesis,a new safety monitoring system for lead-acid battery electrolyte is designed based on optical fibre sensing technology,using the temperature-sensitive characteristics of optical fibre grating and the refractive index-sensitive characteristics of optical fibre FP cavity to achieve real-time online monitoring of the temperature and concentration of sulphuric acid.The system solves the current problem of monitoring equipment operation.The system solves the problems of complicated operation,high price and low monitoring accuracy of current monitoring equipment,and helps to obtain the real-time working status of battery electrolyte in a timely and accurate manner,which can be applied to the safety monitoring of large-scale lead-acid battery arrays in the power industry,solar power generation and submarines,and is of great practical value to improve their safety performance.The main findings of this thesis are as follows:1.A highly sensitive implantable sensing probe was designed based on a fibre optic grating as a sensing element,and a temperature monitoring system based on fibre optic sensing technology was built.The experimental results showed that the temperature of the sulphuric acid solution had good linearity with the central wavelength of the grating in the measurement range of 30-80°C,and the fitting coefficient reached 0.9998.2.A sulphuric acid concentration sensor based on fibre optic FP is designed.The open FP cavity allows the liquid to enter the cavity easily and is less likely to form air bubbles.It can be implanted inside the lead-acid battery to achieve real-time online monitoring of the concentration of sulphuric acid solution in the electrolyte.The results show that the effective cavity length of the FP cavity and the concentration of sulphuric acid solution have a good linearity in the concentration range of 0%-30% of sulphuric acid,with a fit coefficient of 0.995,and the maximum offset between the measured and true values of sulphuric acid solution is within 1.05%.3.The designed sensing probe has the advantages of low invasiveness,resistance to strong acids and alkalis,and resistance to electromagnetic interference,which helps to solve the challenges of traditional monitoring techniques that are complex,cumbersome and costly to operate the equipment.This research provides a real-time and efficient monitoring method for battery monitoring technology,which has wide application prospects in nuclear power plants,submarine submersion and solar power generation.