A method for estimating the state of charge of a liquid or semi-liquid metal battery

Abstract

The invention discloses a liquid or semi-liquid metal-cell state-of-charge estimation method. The method is characterized by according to an equivalent circuit of a cell, acquiring a state space expression; through parameter identification, acquiring a function relation of an equivalent circuit parameter and a SOC; according to a function relation of an initial value of the equivalent circuit parameter, a cell ohm internal resistance, a cell electromotive force and the SOC, acquiring a system matrix initial value, and controlling an input matrix initial value and an observation matrix; using an extended Kalman filtering algorithm to acquire a state estimation time updating matrix and an error covariance time updating matrix; extracting a predicted value of the SOC of the cell, a polarized voltage and a diffusion voltage, and acquiring a value of the cell electromotive force and ohm internal resistance voltage drop; according to the cell electromotive force, the polarized voltage, the diffusion voltage and the ohm internal resistance voltage drop, acquiring observation output; and according to the observation output, acquiring a state measurement updating matrix and extracting a SOC estimation value. By using the SOC estimation method provided in the invention, an accumulate error is eliminated and residual electric quantity changes of the cell can be effectively tracked.

Description

technical field [0001] The invention belongs to the technical field of battery life cycle management, and more particularly relates to a method for estimating the state of charge of a liquid or semi-liquid metal battery. Background technique [0002] Cheap, efficient and long-lived electrochemical energy storage is a key technology for the efficient use of renewable energy and the development of smart grids. Among many energy storage technologies, energy storage batteries are flexible and convenient, have fast response time and low maintenance cost, and have broad application prospects in the field of energy storage. At this stage, relatively mature energy storage batteries include lithium-ion batteries, sodium-sulfur batteries, and flow batteries. However, due to their high cost and short energy storage life, they cannot meet the demand goals of the large-scale energy storage market. best choice possible. [0003] U.S. invention patents 0044725[P], 13237215[P] and the int...

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Problems solved by technology

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method for estimating the state of charge (SOC) of a liquid or semi-liquid metal battery, which solves the problem of large cumulative errors in the existing SOC estimation method

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