A real-time online SOC estimation method and system for a vehicle power battery

Abstract

The invention discloses a SOC real-time online estimation method and system for a vehicle power cell. The method comprises steps that step 1, an accurate power cell mathematics model is constructed, and the accurate power cell mathematics model is inputted to an ECU; step 2, a current signal is acquired, and discharging condition prediction is further carried out, the current signal detected by a current sensor before T1is acquired through a CAN bus, during the T1, the discharging condition after the t is predicted through the intelligent traffic technology and an ECU storage module, and the time is recorded as T2; step 3, virtual standing simulation of the cell is carried out, at the T2, an input current of the power cell mathematics model of the ECU is made to be 0A, virtual standing is carried out, a cell end voltage U2 after 24 hours is calculated through the ECU when the input current is 0A, and the simulation time is t; the acquired U2 is the real-time online cell open-circuit voltage OCV predicted at the T2; step 4, a prediction error of the step 2 is corrected, and the step 3 is repeated; and step 5, a real-time cell SOC value is acquired through cell SOC-OCV relationships according to the acquired OVC.

Description

technical field [0001] The invention belongs to the technical field of new energy vehicles, and in particular relates to a method and system for estimating the SOC value of a vehicle power battery. Background technique [0002] Studies have shown that car ownership will continue to show a rapid upward trend, consume a lot of energy, and bring great pressure and damage to the environment. At present, the development of energy-saving and new energy vehicles has become the consensus of the automotive industry, and electric vehicles are the vanguard of this development direction. Vehicle power battery, as the energy supply part of electric vehicles, is the focus and difficulty of the development of electric vehicle technology. [0003] The SOC value of the power battery is an important performance indicator of the power battery. At present, in order to study the SOC value of the battery, the laboratory generally adopts the discharge experiment method, using a constant current ...

AI Technical Summary

Problems solved by technology

It is a research method for the SOC of the battery state of charge of a hybrid electric vehicle, that is, by calculating the integral of the current and the charging and discharging time for a period of time, calculating the percentage of the changing power, and then estimating the SOC value of the battery, but this method often takes time The longer the cumulative error is, the larger the error may be, which may cause a dangerous working condition of the car

[0004] The invention patent with application number 201610541768.9 establishes a data query library of battery parameters to be tested based on different battery parameters at different temperatures, and introduces battery parameters according to the current battery temperature, and then brings them into the adaptive unscented Kalman algorithm to Obtain the SOC value; although this method improves the influence of temperature on the estimation of the battery SOC value to a certain extent, the temperature changes greatly during the operation of the battery, especially when the battery is discharged with a large current, and the battery parameters need to be updated continuously, which requires a large amount of calculation. Bringing it into the Kalman algorithm will inevitably cause a time lag, and it is impossible to achieve real-time online estimation

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