An online collaborative estimation method for state of charge and state of health of ternary lithium battery
A ternary lithium battery, health status technology, applied in the direction of measuring electricity, measuring electrical variables, instruments, etc., can solve the problems of large error, low applicability, unable to update model parameters in real time, etc., to achieve accurate prediction, simple external circuit, The effect of shortening the development cycle
Active Publication Date: 2021-07-27
XI'AN PETROLEUM UNIVERSITY
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Problems solved by technology
Although this method can complete the joint estimation of lithium battery SOC and SOH, the model parameters are obtained based on specific working conditions under off-line conditions. When the operating conditions and environment change, the model parameters cannot be updated in real time. Therefore, for different operating conditions The applicability to the environment is low, and the error is large
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[0083] The present invention will be specifically introduced below in conjunction with the accompanying drawings and specific embodiments.
[0084] The online collaborative estimation method for the state of charge and the state of health of the ternary lithium battery provided by the present invention is based on the FFRLS algorithm and the improved EKF algorithm to realize the online collaborative estimation of the state of charge and the state of health of the ternary lithium battery, which specifically includes the following steps:
[0085] Step 1: Improve Thevenin Equivalent Circuit Model
[0086] On the basis of the traditional Thevenin equivalent circuit model, a concentration polarization network (RC network) is added. The improved Thevenin equivalent circuit model consists of three parts: voltage source, ohmic internal resistance, and RC network. Among them, the RC network There are two, one is used to simulate the electrochemical polarization phenomenon of the batter...
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The invention discloses a method for online collaborative estimation of state of charge and state of health of a ternary lithium battery. The method improves the Thevenin equivalent circuit model, and obtains the state space equation of the improved Thevenin equivalent circuit model according to the circuit relationship , and further obtained the mapping relationship between OCV and SOC, using the FFRLS algorithm to obtain the specific values of polarization resistance, polarization capacitance and internal resistance at each sampling point by collecting external voltage and current values in real time, and calculating SOC and The parameter values of the Thevenin equivalent circuit model are updated in real time according to the operating status of the BMS at the moment before the SOH, which ensures that the BMS predicts SOC and SOH more accurately. When this method realizes high-precision estimation of the SOC and SOH of the ternary lithium battery, the The circuit is simple, and only conventional BMS is used to collect voltage, current and time values. In addition, this method has strong convergence and is robust to wrong initial values, and iterative cycle calculation method is still used, so The sampling accuracy requirements for BMS can be appropriately reduced.
Description
technical field [0001] The invention relates to a method for estimating the state of charge and state of health of a battery, in particular to an online collaborative estimation method for the state of charge and state of health of a ternary lithium battery, belonging to the technical field of battery management. Background technique [0002] With the transformation of human energy consumption structure, renewable clean energy has attracted much attention. Among them, ternary lithium batteries have been widely used in pure electric vehicles and large-scale energy storage due to their advantages such as high energy density, long cycle life, safe use and low self-discharge rate. In this process, only by realizing good management of the battery can the battery work in an excellent state and at the same time prolong the service life of the battery. Therefore, how to quickly and accurately determine the working state (remaining power) and service life of the battery is one of th...
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IPC IPC(8): G01R31/367G01R31/3842G01R31/388G01R31/392
CPCG01R31/367G01R31/3842G01R31/388G01R31/392
Inventor 刘熹李琳刘海龙陈威冲
Owner XI'AN PETROLEUM UNIVERSITY