Lithium battery state of charge estimation method

Abstract

The invention discloses a lithium battery state of charge estimation method comprising the steps that a battery equivalent circuit model is established and the recursion frequency is set; the real-time voltage and real-time current parameters of the battery are acquired; the real-time voltage and real-time current parameters of the battery are inputted to the battery equivalent circuit model; themodel parameters of the equivalent circuit model are updated through a least square method; and whether the recursion frequency meets the requirement is judged, and the state of charge estimation value of the lithium battery is outputted. The state of charge value of the lithium battery is accurately estimated through combination of the least square method and the Kalman filtering algorithm, the state of charge value of the lithium battery at the current moment is estimated by using the Kalman filtering algorithm, and the model parameters of the equivalent circuit model of the battery are updated by using the least square method according to the state of charge value of the past moment so that the equivalent circuit model is enabled to be adjusted according to the change of the actual application condition of the battery and the estimation accuracy of the state of charge value of the lithium battery can be enhanced. The lithium battery state of charge estimation method is used for estimating the state of charge value of the lithium battery.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method for estimating the state of charge of a lithium battery. Background technique [0002] The rapid development of modern industry has led to an increasing demand for petroleum resources, and the resulting environmental pollution has attracted attention from all sides. As a new power source for energy saving and environmental protection, lithium batteries have been used in industry, daily life and other fields. In electric vehicles industry in particular. As the energy source of electric vehicles, the management of lithium batteries is crucial to electric vehicles. In order to make full use of the energy of each power lithium battery on electric vehicles, it is required to manage lithium batteries reasonably and accurately obtain the lithium battery The state of charge (SOC) has become an important part of lithium battery management. In order to popularize elect...

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Problems solved by technology

[0003] However, in the prior art, the state of charge of the lithium battery cannot be directly measured in practical applications, the main reason being that the lithium battery system itself is a nonlinear system

In the prior art, there is an estimation method based on the definition of the state of charge. Since it needs to be under the condition of constant current and constant temperature, this method is difficult to meet the actual working conditions of the battery, and the rated capacity of the lithium battery is limited. The influence of discharge rate, operating environment temperature, historical working conditions, etc. is not a constant, so this increases the difficulty of estimating the state of charge value

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