Frequency and Temperature Characteristics of an Ultrasonic Method for Measuring the Specific Gravity of Lead-Acid Battery Electrolyte

摘要

In this paper, we present an ultrasonic method for measuring the specific gravity of lead-acid battery electrolyte and study its frequency and temperature characteristics. This method uses an improved frequency scanning ultrasonic pulse echo reflectometer with a two-transducer configuration. The velocity and attenuation coefficient (1 to 30 MHz) of electrolytes with different specific gravities (1.05 to 1.30) are obtained at 25℃. It has been shown that the ultrasonic velocity changes little with frequency, and there is low attenuation at approximately 5 MHz. The velocities of several electrolytes with different specific gravities are measured in the temperature range from 10 to 50℃. The thermal transient of the measurement cell is analyzed, showing 0.1% accuracy in specific gravity measurement for a steady temperature and 0.5% accuracy under thermal gradient conditions after temperature compensation. This method is suitable for the on-line, rapid, and accurate measurement of the specific gravity of a lead-acid battery electrolyte.