Method and apparatus for calculating state of charge upon battery and battery pack

Abstract

The invention discloses a method and apparatus for calculating the state of charge upon charging and a battery pack, and relates to the field of batteries, battery management systems and electric vehicles, aiming at increasing the accuracy of calculating the state of charge upon charging a battery. The method comprises the following steps: acquiring the fully-charged cut-off voltage of a to-be-measured battery and any one charging voltage curve; acquiring a preset reference voltage in the approximately linear rising stage of the charging voltage curve, and acquiring a corresponding reference state of charge; acquiring the current charging voltage in the approximately linear rising stage of the charging voltage curve of the to-be-measured battery; based on the preset reference voltage, the fully-charged cut-off voltage and the current charging voltage, determining a compensation coefficient; using the compensation coefficient and the reference state of charge to calculate the current state of charge under current charging state of the to-be-measured battery, and the compensation coefficient converting the voltage difference between the current charging voltage and the preset reference voltage to the difference of state of charge between the current state of charge and the reference state of charge.

Description

Technical field [0001] The present invention relates to the fields of batteries, battery management and electric vehicles, and in particular to a method, device and battery pack for calculating the remaining power during battery charging. Background technique [0002] With the development of industrial technology, batteries are also used as power sources in more and more fields. SOC (State of Charge, also known as remaining power) refers to the ratio of the remaining power of the battery to the rated capacity under the same conditions under a certain discharge rate. The battery management system will calculate the remaining power of the battery, and the user can see It is the calculated remaining power displayed, which enables the user to know the charging progress of the battery by viewing the remaining power displayed when charging the battery. [0003] At present, the ampere-hour method or the open circuit voltage method is generally used to calculate the remaining power, but b...

AI Technical Summary

Problems solved by technology

However, in the process of calculating the remaining power of the battery using the open circuit voltage method, the time for the battery to stand still until the voltage stabilizes cannot be accurately determined. The voltage is often calculated when the battery has not yet reached a stable voltage state. At this time, the calculated remaining power and the actual remaining power There is also a large error between

If the error between the calculated remaining power and the actual remaining power is large, the battery may not be fully charged due to the large calculated remaining power during battery charging. For example, the actual remaining power is 97%. , the calculated remaining power is 100%. When the default remaining power of the battery is 100%, the battery is fully charged and charging is stopped, but the actual battery power cannot be fully charged.

During the battery charging process, there may also be a phenomenon that the remaining power displayed to the user jumps due to the small remaining power calculated. For example, the actual remaining power is 99%, and the calculated remaining power is 96%. When the actual remaining power reaches 100%, the remaining power calculated by the battery is 100% by default, and the displayed remaining power will jump from 96% to 100%

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