Limits...
Resolution in QCM sensors for the viscosity and density of liquids: application to lead acid batteries.

Cao-Paz AM, Rodríguez-Pardo L, Fariña J, Marcos-Acevedo J - Sensors (Basel) (2012)

Bottom Line: However, there is greater dependency between electrolyte viscosity and SoC than that seen for density and SoC.At the same time, the present theoretical "resolution limit" to measure the square root of the density-viscosity product [Formula: see text] of a liquid medium or best resolution achievable with a QCM oscillator is determined.The QCM resolution limit for [Formula: see text] measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Technology, University of Vigo, Campus Lagoas Marcosende, Vigo 36310, Spain. amcaopaz@uvigo.es

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 H(2)SO(4) 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 [Formula: see text] 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 [Formula: see text] measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

No MeSH data available.


Related in: MedlinePlus

Calibration plot of the QCM sensor.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3472846&req=5

f7-sensors-12-10604: Calibration plot of the QCM sensor.

Mentions: With respect to the calibration with sulfuric solutions, Figure 6 shows both the frequency changes when concentrated acid is added and the liquid temperature. Frequency has some ascending peaks which correspond to pure acid addition. This action produces an exothermic reaction and frequency is affected by temperature increment. A few minutes later liquid temperature returns to its stable value (30.8 °C) and the frequency shift responds only to the square root of the density-viscosity product. Taking the values of frequency and density measurements in areas where the temperature becomes constant again (linear zones of frequency steps in Figure 6), the calibration plot in Figure 7 was obtained, and an experimental sensitivity of was determined for this sensor. The theoretical sensitivity coefficient calculated by Equation (2) is .


Resolution in QCM sensors for the viscosity and density of liquids: application to lead acid batteries.

Cao-Paz AM, Rodríguez-Pardo L, Fariña J, Marcos-Acevedo J - Sensors (Basel) (2012)

Calibration plot of the QCM sensor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472846&req=5

f7-sensors-12-10604: Calibration plot of the QCM sensor.
Mentions: With respect to the calibration with sulfuric solutions, Figure 6 shows both the frequency changes when concentrated acid is added and the liquid temperature. Frequency has some ascending peaks which correspond to pure acid addition. This action produces an exothermic reaction and frequency is affected by temperature increment. A few minutes later liquid temperature returns to its stable value (30.8 °C) and the frequency shift responds only to the square root of the density-viscosity product. Taking the values of frequency and density measurements in areas where the temperature becomes constant again (linear zones of frequency steps in Figure 6), the calibration plot in Figure 7 was obtained, and an experimental sensitivity of was determined for this sensor. The theoretical sensitivity coefficient calculated by Equation (2) is .

Bottom Line: However, there is greater dependency between electrolyte viscosity and SoC than that seen for density and SoC.At the same time, the present theoretical "resolution limit" to measure the square root of the density-viscosity product [Formula: see text] of a liquid medium or best resolution achievable with a QCM oscillator is determined.The QCM resolution limit for [Formula: see text] measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Technology, University of Vigo, Campus Lagoas Marcosende, Vigo 36310, Spain. amcaopaz@uvigo.es

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 H(2)SO(4) 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 [Formula: see text] 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 [Formula: see text] measurements worsens when the density-viscosity product of the liquid is increased, but it cannot be improved by elevating the work frequency.

No MeSH data available.


Related in: MedlinePlus