Method and device for determining state of charge of a battery

Abstract

The embodiment of the invention discloses a battery charge state determination method and a device, wherein the phenomenon that the charge state goes beyond the normal physical range is reduced. The method comprises the steps of according to the equivalent circuit model of a battery and the Kalman filtering algorithm, obtaining a first parameter value for the relevant parameters of the battery charge state; if the first parameter value is within a preset range, obtaining an optimal solution for the battery charge state at the current moment based on the first parameter value; if the first parameter value is out of the preset range, replacing the first parameter value with a preset second parameter value for the relevant parameters, and obtaining the optimal solution for the battery charge state at the current moment, wherein the second parameter value is within the preset range.

Description

technical field [0001] The present application relates to the field of batteries, in particular to a method and device for determining the state of charge of a battery. Background technique [0002] With the shortage of petroleum energy and the continuous expansion of air pollution, the development of electric vehicles (Electrical Vehicle, EV) is becoming more and more important. Electric vehicles generally include pure electric vehicles (Battery Electrical Vehicle, BEV) and hybrid electric vehicles (Hybrid Electric Vehicle, HEV). For electric vehicles, batteries are the core technology. The battery of an electric vehicle is generally a battery, and the remaining power of the battery is generally expressed by SOC (State of Charge, state of charge). Ratio, commonly expressed as a percentage. Its value ranges from 0 to 1. When SOC=0, it means that the battery is completely discharged, and when SOC=1, it means that the battery is fully charged. [0003] The prior art estima...

AI Technical Summary

Problems solved by technology

However, the noise of the Kalman filter algorithm applied to the calculation of the battery state of charge is not known, so it is necessary to estimate the noise

If the noise estimation is inaccurate, the calculated state of charge will exceed the normal physical range (that is, the state of charge is less than zero or greater than 1), that is, the obtained state of charge is invalid

In addition, the calculation of the state of charge requires the participation of the initial state of the system. In general, the initial state of the system is also an estimated state. If the estimated value deviates greatly from the actual value, the calculated state of charge may exceed Phenomena in the normal physical range

If the state of charge exceeds the normal physical range, errors will continue to accumulate during the iterative process of the Kalman filter algorithm, resulting in an increasingly inaccurate optimal solution for the state of charge

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