Resolution in QCM Sensors for the Viscosity and Density of Liquids: Application to Lead Acid Batteries

Abstract

In battery applications, particularly in automobiles, submarines and remote communications, the state of charge (SoC) is needed in order to manage batteries efficiently. The most widely used physical parameter for this is electrolyte density. However, there is greater dependency between electrolyte viscosity and SoC than that seen for density and SoC. This paper presents a Quartz Crystal Microbalance (QCM) sensor for electrolyte density-viscosity product measurements in lead acid batteries. The sensor is calibrated in H2SO4 solutions in the battery electrolyte range to obtain sensitivity, noise and resolution. Also, real-time tests of charge and discharge are conducted placing the quartz crystal inside the battery. At the same time, the present theoretical “resolution limit” to measure the square root of the density-viscosity product false(ρηfalse) of a liquid medium or best resolution achievable with a QCM oscillator is determined. Findings show that the resolution limit only depends on the characteristics of the liquid to be studied and not on frequency. The QCM resolution limit for ρη measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

Highly Enhanced Inductance Sensing Performance of Dual-Quartz Crystal Converter

“…By switching between the reference and measuring inductance, the quartz crystal non-linear self-temperature frequency characteristics as well as parasitic influences of the converter electronic circuit are compensated. An additional advantage of the proposed method—when comparing the temperature stability during the temperature changes in the range between 0–40 °C to other methods [15,16,17]—is that no temperature sensor is needed.…”

Bulk Acoustic Wave Characteristics of Pseudo Lateral-Field-Excitation on LGT Single Crystal for Liquid Phase Sensing

“…Studies show that lateral-field-excitation (LFE) bulk acoustic waves are sensitive to variation in the electrical and mechanical characteristics of the analytes [ 1 ]. Therefore, LFE-based sensors are capable of providing more useful information from analytes in comparison to the conventional thickness-field-excitation (TFE) devices [ 2 , 3 , 4 , 5 , 6 , 7 ]. Hempel et al analyzed the AT-cut quartz LFE devices from impedance point of view [ 8 ].…”

Detection of Cu(II) Ion in Water Using a Quartz Crystal Microbalance

“…Frequency shifts of a QCM provide information on absorbed mass changes at QCM surface [9]. Therefore, the QCM was utilized in various fields such as environmental protection [10][11][12], lead acid batteries [13][14][15][16] and biomedicine [17][18][19]. For constructing functional and efficient chemical sensors, the modification of sensing films on the QCM electrode was been studied to greatly improve their properties [20].…”