Density measurement into lead-acid batteries with multipoint optical fiber sensor

Abstract

There are numerous applications for the use of leadacid batteries: automotive applications, telecommunications, UPS, remote-area power-supply systems, etc. Modern energystorage applications require higher reliability than has been demanded in the past; in addition, systems have been developed for monitoring and managing the batteries so as to achieve duty in service. For determination of battery state, it is necessary to know the state of charge (SOC) and the state of health (SOH), one of the physical parameters with information about the SOC is the electrolyte density. An electrolyte density sensor must be able to measure the electrolyte density at different places because the battery-density varies with location. This paper presents a plastic optical fiber sensor developed for measuring in real time the electrolyte density into lead-acid batteries. The sensor measures the density at four different heights.The environment in the batteries that use an electrolyte with Sulfuric Acid (H 2 SO 4 ) at an elevated temperature during the use process is very hard and the accuracy of the density readout must be maintained through the useful life of the vehicle. We have done an accelerated test to check the reliability sensor. The test duration was over one calendar year (9,552 hours) using a sensor with four optical fibers. For the test, the electrolyte acid density was set to 35%, and the temperature to 70 degrees Celsius. An electronic system for emission and detection of light collected data periodically to assess the transmission loss in the fibers as they aged. In this paper we present the test results.

Free Suspended Thin-Walled Nickel Electroplated Tubes for Microfluidic Density and Mass Flow Sensors

“…O VER the past decades, a large variety of applications have been presented for micromachined density sensors, such as the estimation of the state of the charge (SOC) and the state of health (SOH) in batteries [1], controlling the insulation gas in high voltage switchgears [2], and checking the percentage of sucrose and alcohol in the beverage industry [3].…”

Thin-Walled Cylindrical Nickel Electroplated Tubes for Application in Microfluidic Density and Mass Flow Sensors

“…Over the past decades, a large variety of applications has been presented for micromachined density sensors, such as estimation of the state of the charge (SOC) and state of health (SOH) in batteries [1], controlling the insulation gas in high and medium voltage equipment [2], and checking the percentage of sucrose and alcohol in the beverage industry [3]. The basic principle of density measurement of a fluid inside a vibrating tube is that the density of the fluid directly affects the resonance frequency of the tube.…”