Lithium-ion battery SOC prediction method and device based on equivalent circuit model

Abstract

The invention discloses a lithium ion battery SOC prediction method and device based on an equivalent circuit model. The method comprises the steps: employing an end voltage U, charging / discharging current I, SOC (State Of Charge), capacity Q, discharge depth and capacity voltage differential parameter dQ / dV to represent the performance and fault of a lithium ion battery, so as to build the equivalent circuit model based on the Thevenin theorem; taking the end voltage U, charging / discharging current I, SOC (State Of Charge), capacity Q, discharge depth and capacity voltage differential parameter dQ / dV as the input variables according to the corresponding relation between the capacity voltage differential parameter dQ / dV and the SOC, taking the SOC as the output variable, and building a data pair set. and building a prediction model according to the data pair set. The method predicts the SOC through the end voltage and charging / discharging current, and improves the estimation accuracy of SOC.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery fault prediction and health management, in particular to a lithium-ion battery SOC prediction method based on an equivalent circuit model. In addition, the invention also relates to a lithium-ion battery SOC prediction device. Background technique [0002] As a new type of storage battery, lithium-ion batteries have great application prospects, especially in occasions where the electrical performance and reliability of energy storage are required to be high, such as aerospace equipment such as low earth orbit, geosynchronous orbit, and space stations. [0003] The State of Charge (SOC) of the battery is used to describe the remaining capacity of the battery. At present, it is relatively unified to define SOC from the perspective of electricity, which is defined as the remaining capacity of the battery under a certain discharge rate and the rated capacity under the same conditions. It ...

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Problems solved by technology

However, in the prior art, most of the methods of estimating SOC based on the open circuit voltage have certain limitations in practical applications, specifically: the open circuit voltage is not easy to measure in practical applications, and there is a phenomenon of hysteresis when using the open circuit voltage to estimate SOC

In addition, the complex electrochemical reaction process inside the lithium-ion battery is difficult to characterize, which brings certain difficulties to the estimation of SOC, which leads to inaccurate estimation of the SOC of the lithium-ion battery and fails to truly reflect the change of the battery SOC. The failure prediction and health management of the lithium-ion battery used has brought many difficulties

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