| The rapid development of lithium battery industry provides an effective solution for environmental protection.Therefore,China vigorously advocates the development of new energy technology industry.One of the most important components of electric vehicles is the battery,but the development of electric vehicles is largely limited by the battery pack.A specific foreign brands,therefore,the ternary lithium battery as the main research object,the battery charged state estimation and battery management system,to develop large discharge rate,high safety and reliability of the lithium battery pack,the study of monitoring technology at the same time,establish the platform reliability test to validate,the this article main work is as follows:1.Battery cell quality is the basis of battery pack,different lithium battery cell charging and discharging performance is very different.Moreover,the charge and discharge of lithium battery itself is a very complex chemical process with strong time-varying,and the measurement of battery parameters is easily interfered by external factors.By comparing the test standards of cell at home and abroad,this topic found that the charging and discharging performance of cell is mainly closely related to the discharge rate and temperature,so for the cell to develop different discharge rate,temperature,impedance,cycle life and other testing programs,and then through the comparative analysis of the experimental data between 18650 and 21700 cell differences.2.By comparing the electrochemical model and equivalent circuit model of the lithium battery,the second-order RC equivalent circuit model was finally selected as the model of the lithium battery in this paper,and the parameters were identified by the recursive least square method with genetic factors.On the basis of the existing model,the Kalman filter algorithm is used to estimate the SOC of ternary lithium battery.However,the commonly used Kalman filter algorithm is mainly used in the linear system.However,the charging and discharging process of lithium battery has a strong non-linearity,so an extended Kalman filter is proposed to estimate the SOC of lithium battery packet.The method of estimating battery SOC by using the recursive least square method with genetic factors and the extended Kalman filter is correct and high precision.3.Through the research of battery management system,it is known that it is the key to prolong the service life of lithium battery pack.For this reason,this paper puts forward the strategy of using IC and MCU to control the battery pack together,and the internal I2C method is used to provide reliable and stable communication,mainly to protect the battery pack from overcharge,overdischarge,temperature,current,short circuit and other situations.The practice has proved that this method can fully meet the user needs.4.The design of battery reliability test platform based on Lab VIEW can provide data support for battery pack in the development and reliability verification stage.Through the study of monitoring technology,this paper adopts NI acquisition card and Compact DAQ chassis to build a test platform,and visually displays the collected data through Lab VIEW software.Data collection is mainly carried out through each hardware module,and then real-time synchronous transmission to the upper computer.After logic processing by software,it is clearly displayed in the user interface.The verification shows that the test platform can realize the real-time monitoring of battery pack status online. |
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