Method for measuring voltage difference before and after charging or discharging of battery pack as well as measuring circuit

Abstract

The invention relates to a method for measuring a voltage difference before and after a battery pack is charged or discharged at high precision, comprising the following steps: (1) connecting the battery pack with one voltage holding device, so that the voltage holding device acquires and obtains an initial voltage V0 of the battery pack; (2) connecting the battery pack with a power supply to be charged or with a load to be discharged, and obtaining a voltage V1 of the battery pack after being charged or discharged; and (3) connecting the voltage holding device and the battery pack with the input terminal of a differential amplifier at the same time, and connecting the output terminal of the differential amplifier with the input terminal of a digital-to-analog converter, thus an amplifiedhigh-precision voltage difference is obtained at the output terminal of the digital-to-analog converter. In the measuring method and a measuring circuit of the invention, a capacitor is adopted for holding a voltage value of the battery pack before being charged or discharged, then the voltage difference before and after the battery pack is charged or discharged is directly obtained by virtue of adifferential pressure amplifier, a voltage division circuit is avoided from being used for acquiring a voltage absolute value before and after charging or discharging, signal attenuation is greatly reduced, and the method provided by the invention is applicable to a battery pack of 1V to infinite Volts.

Description

technical field [0001] The invention relates to a method for measuring voltage difference before and after charging and discharging of a battery pack, a method for measuring DC internal resistance and a measuring circuit, and is especially suitable for measuring a battery pack with a wide voltage range. Background technique [0002] The internal resistance of the battery refers to the resistance that the current flows through the battery when the battery is working. It includes the ohmic internal resistance and the polarization internal resistance, and the polarization internal resistance includes the electrochemical polarization internal resistance and the concentration polarization internal resistance. resistance. [0003] Different types of batteries have different internal resistances. The same type of battery, due to the inconsistency of the internal chemical characteristics, the internal resistance is not the same. The internal resistance of the battery is very small...

AI Technical Summary

Problems solved by technology

In order to meet the requirements of the input range of the current high-precision analog-to-digital converter, it is necessary to use an amplifier to amplify the voltage difference signal, and the magnification ratio is relatively large. If this is done, the DC noise will be amplified year-on-year, resulting in the final 24bitΣ△-type analog-to-digital converter The measurement error is more than 20%, and it is difficult to meet the error requirement of less than 10%

In short, the traditional DC internal resistance measurement method has the problems of large dynamic range and poor accuracy.

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