A method for detecting the state of charge of a battery

Abstract

The invention discloses a battery charge state detecting method. The method comprises the steps that the initial SOC of a battery is determined; the self-discharge effect of the battery is considered; a table look-up method is used to accurately estimate the SOC of the battery; an ampere-hour integral method is used to acquire the SOC estimation value of the battery of a next moment; a battery Thevenin model is combined, and an extended Kalman filter algorithm is used to correct the SOC of the battery; and finally, low power, over-current, over-temperature and the like of the battery are judged to carry out early warning and protection. According to the method provided by the invention, the influence of self-discharge of the battery on the battery capacity and the influence of temperature, the number of times of cycle charge and discharge and charge and discharge current on the rated capacity of battery are comprehensively considered, wherein self-discharge of the battery is caused by first time of running and downtime of the battery; error correcting is carried out on the SOC of the battery; and the accuracy is improved.

Description

technical field [0001] The invention belongs to the field of electrical engineering, and relates to a battery management system, in particular to a method for detecting the state of charge of a battery. Background technique [0002] With the continuous consumption of fossil energy, electric vehicles will become a new means of transportation and gradually replace traditional vehicles that rely on fossil energy. However, battery is the energy source of electric vehicles, and its correct management will directly affect the safety and stable operation of electric vehicles. Therefore, it is very important to estimate the state of charge (SOC) of the battery in the battery management system, that is, the remaining power of the battery. Inaccurate battery SOC estimation will lead to incorrect grasp of the real-time state of the battery, which may lead to excessive battery life. Charging and over-discharging, even overheating and other phenomena. These hazards will cause permanent...

AI Technical Summary

Problems solved by technology

[0010] (1) It is difficult to determine the initial SOC of the battery; because the initial SOC of the battery is related to the charging and discharging conditions that occurred before, before the previous state of the battery is unknown, the estimation accuracy of the initial SOC of the battery is difficult to meet, and the initial SOC of the battery is also Affects the subsequent real-time estimation of battery power

[0011] (2) During the actual operation of electric vehicles, severe voltage and current fluctuations can easily introduce electromagnetic interference and noise signals. Such noise will cause SOC estimation errors, and the errors will continue to accumulate

Although it can be solved by increasing the sampling frequency, the current sampling frequency will also be limited by the battery management system's operating environment, operating speed, and hardware. This problem is still not well resolved.

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