Lithium ion power battery safety degree estimation method and estimation device based on double Kalman filtering

Abstract

The invention discloses a lithium ion power battery safety degree estimation method and estimation device based on double Kalman filtering, and belongs to the technical field of battery safety degreeestimation. 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 steps of constructing an equivalent model of a battery; acquiring load current and load voltage of the battery, obtaining polarization voltage and open-circuit voltage of the equivalent model through the equivalent model, and obtaining an SOC percentage maximum value and optimal voltage through Kalman filtering; acquiring the temperature of the battery, and performing Kalman filtering on the temperature to obtain atemperature estimated value; and performing fuzzy control on the optimal battery SOC, the optimal voltage and the temperature estimation value to generate the battery safety degree. The real-time safety degree of the battery is quantified and accurately estimated in combination with related factors of the battery.

Description

technical field [0001] The invention relates to the field of safety degree estimation, in particular to a double Kalman filter-based lithium-ion power battery safety degree estimation method and estimation device. Background technique [0002] Electric vehicles are in a new stage of rapid development in China, and the development of electric vehicles has driven 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. Once the battery reaches a certain critical condition, such as overvoltage, overtemperature, and low life, if the corresponding safety precautions are not taken in time, the thermal runaway of the battery will inevitably lead to a safety accident. [0003] Battery safety accidents come from thermal runaway, and there are two main causes of thermal runaway, one i...

AI Technical Summary

Problems solved by technology

Once the battery reaches a certain critical condition, such as overvoltage, overtemperature, and low life, if the corresponding safety precautions are not taken in time, the thermal runaway of the battery will inevitably lead to a safety accident

[0003] Battery safety accidents come from thermal runaway, and there are two main causes of thermal runaway, one is mechanical and electrical causes (caused by accidents such as acupuncture and collisions), and the other is electrochemical causes (overcharge, fast charge, spontaneous short circuit, etc.) etc.), the thermal runaway of the battery cell is transmitted to the adjacent cells, and then spreads in a large area, eventually leading to the occurrence of safety accidents

The development of thermal runaway also has a certain stage. According to relevant data, the initial temperature of SEI film decomposition is about 100 degrees Celsius to 130 degrees Celsius. This temperature is also regarded as the starting point of a series of thermal runaway temperatures, and the temperature reaches 300 degrees Celsius. When the temperature of the battery reaches the peak, the temperature of the battery will rise sharply. If no corresponding safety measures are taken, there is no doubt that the battery will cause irreparable damage to the user when the temperature reaches the peak.

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