Research Of Lithium Battery Charge And Discharge Characteristics In Flame-proof Environments

Along with the increase of coal mines, the coal mine electricity equipment growth fast. On the one hand, it put forward higher request for its safe and reliable power supply, on the other hand in some mobile equipments also puts forward the requirement of the portability. And whether uninterruptible power supply or electric locomotive, portable monitoring equipment, etc., are put forward for energy storage battery higher capacity and safety requirements. Compared to conventional lead-acid batteries, lithium ion battery, for its high energy quality ratio and volume ratio, no memory effect, low self-discharge rate, longer service life and other characteristics, be the first choice of the coal mine underground energy storage device. In order to promote the lithium-ion battery in the coal mine safe and reliable application, we must want to understand the lithium-ion battery’s charging and discharging characteristics which in the coal mine flame-proof closed environment, which provides the reference for the design of the of charge and discharge circuit, battery management system and protection. In view of this, this study is very necessary.This paper first introduces the related characteristics of lithium battery at home and abroad, application status and the research status of lithium battery charge and discharge, and using the lithium iron phosphate battery as the research object, illustrates its working principle. And then it introduced the key performance and characteristic parameters of lithium-ion batteries, in view of the lithium battery charge and discharge characteristics, made on temperature characteristic. Then, this paper introduces the definition of battery’s state of charge, and predict it by using various methods. In the research on the basis of the original battery model, comparing the advantages and disadvantages of several models, Thevenin model was put forward. Due to the low monomer battery voltage, capacity is small, so the actual need when using several parallel of monomer battery of battery pack and then used. There are inevitable inconsistencies shortcomings in monomer battery, we need to get the battery pack to join balanced control structure. This paper uses the non-dissipative two-way balanced circuit, in order to energy which between adjacent two monomer battery can be two-way flow, compared with the energy dissipation method it reduce the energy losses. In order to study the lithium iron phosphate batteries in mine flame-proof, airtight, heat charge and discharge characteristics of bad working conditions, design a set of charging and discharging test collection device. In the hardware design of acquisition unit, adopted TMS320LF2407DSP by TI company as the main controller, the peripheral circuit mainly includes signal acquisition and serial communication circuit design, need to collect the signals including single cells in monomer battery voltage, temperature, battery voltage and battery current value. It using the RS-232serial communication circuit of the communication design. The data which collected from the cell will be transmitted to host machine. We designed the PC software, for this PC software completed data processing, display and storage.This acquisition device, which put the LPF batteries in simulated mine flame-proof, airtight, and poor heat dissipation, flame-proof cavity, the actual test LPF battery charge and discharge characteristics, conclude its charge and discharge characteristic curve in this environment. By the characteristic curve, through curve fitting method, and identify the parameters in the model, its mathematical expression, established the mathematical model of this kind of environment for LPF battery. For equilibrium circuit, we set the actual circuit, and do some related experiment, it shows that the equilibrium circuit can complete equilibrium task. Finally, in the MATLAB/Simulink environment, we build the battery model circuit, to verify this model, and drawn the conclusion. For the LPF batteries in the safe and efficient application of flame-proof environment lay a certain foundation.In the end, there is a summary and scope for this paper.