Battery safety degree estimation method and estimation device based on second-order RC equivalent circuit model

Abstract

The invention discloses a lithium ion power battery safety degree estimation method and an estimation device based on a second-order RC equivalent circuit model, and belongs to the technical field ofbattery safety degree estimation. The invention aims to solve the problem that the safety of the power battery cannot be quantitatively expressed and evaluated in the prior art. The method comprises the following steps: constructing a second-order RC equivalent circuit model; S2, identifying the parameters in the step S1 by using a least square method; obtaining a battery SOH according to the identified parameters; constructing a BP neural network, taking the ohmic internal resistance, the electrochemical polarization internal resistance, the concentration polarization internal resistance andthe battery SOH as neural network input, taking the battery safety degree as output for training, and inputting to-be-tested data into the trained model to obtain a real-time and accurate safety degree value. According to the method, the safety degree value of the power battery is estimated through historical data in combination with the second-order RC equivalent circuit model and the BP neural network model and is continuously corrected.

Description

technical field [0001] The invention relates to the field of battery safety degree estimation, in particular to a battery safety degree estimation method and an estimation device based on a second-order RC equivalent circuit model. Background technique [0002] Electric vehicles are in a new stage of rapid development in China, and the development of electric vehicles has promoted the development of the power battery industry. However, accidents such as battery spontaneous combustion and explosion have occurred frequently in recent years, and people are paying more and more attention to the safety of new energy vehicle battery systems. The safety of the battery refers to the fact that the battery does not burn, explode, produce toxic and harmful gases, or cause harm to users during use. The quantitative description of its safety during use is called battery safety. How to achieve real-time and accurate safety estimation has always been a bottleneck problem in the design pro...

AI Technical Summary

Problems solved by technology

Most of the research focuses on measuring the discharge characteristics of different rates, different temperature discharge characteristics, different temperature self-discharge characteristics, over-discharge characteristics, capacity distribution test, resistance distribution test and electrostatic discharge test to analyze its reliability, but these parameters are in Difficult to obtain during battery operation

However, the research related to battery safety in the current research usually adopts the method of fault diagnosis, but this method only judges the fault problem after the battery fails, and does not prevent the occurrence of battery failure.

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