A new method for estimating SOC of electric vehicle power battery

Abstract

The invention discloses a novel electric automobile power battery SOC estimation method, which comprises the following steps: 1) serving a battery pack as a whole body, defining the heat absorbed by the battery pack every a 1-DEG C temperature rise as overall average heat capacity C-bar of the battery and measuring the value thereof; 2) obtaining battery SOC (t-[delta]t) at a precious time, an open-circuit voltage U(t0) of the battery at the initial time, battery temperature Tt, motor real-time input voltage Umotor t and input current Imotor t and the like in real time; 3) measuring flow v(t) of a current battery air cooling system within unit time, inlet air temperature T inlet (t) and outlet air temperature T outlet (t) as well as temperature T pipe i (t) of a plurality of sections of pipe wall of the cooling system through sensors; 4) defining battery SOC as ratio of battery residual energy to battery total energy, and based on the data above, carrying out calculation on electric automobile power battery SOC through an SOC calculation formula; and 5) returning the calculated SOC value to a battery management system as data for estimating battery SOC at the next time, and repeating the steps 2)-5).

Description

technical field [0001] The invention relates to the field of battery management, in particular to a novel method for estimating the SOC of a power battery of an electric vehicle. Background technique [0002] The remaining power of the battery, also known as the State of Charge (SOC) of the battery, is one of the important parameters of the battery state, and provides a basis for the control strategy of the electric vehicle. Accurately estimate the remaining power of the current battery, ensure that the SOC is maintained within a reasonable range, and prevent damage to the battery caused by overcharging or overdischarging, which provides a technical direction for us to use the battery rationally, improve the service life of the battery, and reduce maintenance costs. How to obtain the battery SOC value accurately and reliably is the most basic and important task of the battery management system. [0003] At present, vehicle manufacturers, power battery companies, and scienti...

AI Technical Summary

Problems solved by technology

The ampere-hour integration method has high requirements for current sampling accuracy, otherwise a large cumulative error may occur after long-term operation. In fact, there is a certain error in the current ampere-hour integration method.

In addition, the Kalman filter method and the fuzzy neural network method are common. Due to the hardware limitation of the battery management system and the maturity of the algorithm itself, it has not been verified by a large number of practical applications.

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