Method for judging charge-discharge state of lithium iron phosphate battery

Abstract

The invention provides a method for judging the charge-discharge state of a lithium iron phosphate battery, and the method comprises the steps: obtaining a standard charge or discharge curve of a first standard battery, and obtaining the standard slope of the standard charge or discharge curve; performing charging or discharging processing on the to-be-detected battery, obtaining charging or discharging voltage of the to-be-detected battery at preset time intervals, and obtaining a real-time charging or discharging curve according to the charging or discharging voltage and the preset time intervals; acquiring a real-time slope at each time point on the real-time charging or discharging curve; and comparing the difference value between the real-time slope and the standard slope with a preset difference value, determining that the to-be-detected battery reaches a discharge termination state when the first difference value is smaller than the preset difference value, and determining that the to-be-detected battery reaches a fully charged state when the first difference value is greater than the preset difference value. The method has the beneficial effect that whether the battery reaches a fully charged state or a discharge termination state is judged by judging the slope change of the voltage data along with time in the charging and discharging process.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for judging the charge and discharge state of a lithium iron phosphate battery. Background technique [0002] Lithium iron phosphate batteries are divided into three states during the charging and discharging process, that is, the state of full charge, the state of end of discharge, and the normal state between full charge and end of discharge. [0003] At present, the state of the battery is usually judged by the voltage, that is, when the voltage exceeds a certain set value, the battery is considered to be fully charged, and when the voltage is lower than a certain set value, the battery is considered to be in the end of discharge state; however, as the battery ages, The voltage of the battery will change after it is actually fully charged. If you always use the set voltage of a new battery to judge whether the battery is fully charged, it will cause overcharge and o...

AI Technical Summary

Problems solved by technology

[0005] However, in practical applications, the lithium iron phosphate battery will work with the battery management system. The data acquisition module of the battery management system will collect the voltage data and current data of the battery in real time. According to the observation of big data, there are often errors in the data acquisition process, such as: Under normal circumstances, the voltage data of the battery will become higher and higher during the charging process, but occasionally there will be cases where the voltage data of 1 or 2 points is lower than the previous voltage data. In this case, use a fixed time period to collect the voltage It is often impossible to judge the slope by the difference, and it is very easy to cause misjudgment, which is not advisable in practical applications.

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