High-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect

Abstract

The present invention discloses a high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect, comprising a tuning fork body formed of piezoelectric material; the tuning fork body comprises a tuning fork base and two or more tuning fork arms provided on the tuning fork base; each tuning fork arm is embedded with at least one excitation electrode and at least one sensing electrode; all excitation electrodes are connected to an excitation electrode connection point via wires; all sensing electrodes are connected to a sensing electrode connection point via wires; the excitation electrode connection point and the sensing electrode connection point are respectively provided on the tuning fork base for electrical connection with external wires; the outer peripheral surface of the tuning fork body corresponding to the tuning fork arm is provided with a metal-plated electrode with adjustable electrode potential. The present invention has the characteristics of high robustness, high quality factor and high sensitivity, is suitable for working condition measurement in harsh environments, and is expected to be applied to fields such as petrochemical, food, gas sensing, medicine and scientific research.

Description

Technical Field

[0001] The present invention relates to the technical field of electromechanical coupling sensor equipment, and in particular to a high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect. Background Art

[0002] Traditional methods for measuring liquid density, such as density bottles, hydrometers, and glass floats, generally require manual operation and calculations, resulting in low efficiency and unsuitable for continuous online measurement. Furthermore, traditional viscosity measurement methods, including capillary tubes, rotational methods, and falling ball methods, are complex and difficult to implement online. Modern measurement methods utilize the relationship between liquid density and viscosity and physical quantities such as pressure, sound waves, radiation, or vibration frequency to achieve indirect measurement. These physical quantities are converted into electrical signals for online measurement and are a key measurement technology being developed and applied in modern industrial settings. Compared to existing or traditional oil condition sensor principles, tuning fork sensor devices can be easily miniaturized and integrated, enabling simultaneous measurement of four parameters: viscosity, density, dielectric constant, and temperature, in various harsh high and low temperature environments. Lithium niobate tuning forks, due to their high stability, high accuracy, and low power consumption, have become an essential component for online frequency measurement. At the same time, lithium niobate material has better temperature stability and higher mechanical strength, which enables it to work in harsh environmental conditions. Lithium niobate tuning forks also have lower phase noise levels, which is very important for some applications that require high frequency stability and accuracy, such as in-situ online measurement of the physical and chemical properties of electrolytes. However, most existing tuning forks are limited to their use in conductive solutions (such as lithium-ion electrolytes) due to their exposed electrodes. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect to solve the problem that the electrodes of the traditional two-electrode quartz tuning fork are exposed and short circuit is easy to occur when operating in a conductive medium.

[0004] The technical solution adopted in the present invention is:

[0005] A high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect includes a tuning fork body formed of piezoelectric material; the tuning fork body includes a tuning fork base and two or more tuning fork arms arranged on the tuning fork base; each tuning fork arm is embedded with at least one excitation electrode and at least one sensing electrode; all the excitation electrodes are connected to the excitation electrode connection point through wires; all the sensing electrodes are connected to the sensing electrode connection point through wires; the excitation electrode connection point and the sensing electrode connection point are respectively arranged on the tuning fork base so as to be electrically connected to external wires; the outer peripheral surface of the tuning fork body corresponding to the tuning fork arm is provided with a metal-plated electrode with adjustable electrode potential.

[0006] Furthermore, the two tuning fork arms and the tuning fork base are integrally formed.

[0007] Furthermore, the tuning fork body has a U-shaped structure.

[0008] Furthermore, the tuning fork body is made of lithium niobate (LiNbO3) piezoelectric material; the excitation electrode and the sensing electrode are embedded in the interior of the piezoelectric material LiNbO3 tuning fork, and the metal-plated electrode wrapped around the outer surface of the tuning fork can be grounded or a polarization voltage (potential is adjustable) can be applied according to the working mode.

[0009] Furthermore, the sensing electrode and the excitation electrode are formed of any metal electrode material (Au / Pt / Cu / Al, etc.), and the metal-plated electrode is an inert metal that is resistant to oxidation; or a coating that has an adsorption effect on the gas / liquid medium environment.

[0010] Furthermore, the embedding processing technology of the sensing electrode and the excitation electrode is not limited, and the geometric structure can be adjusted to an embedding structure arranged parallel to the vibration direction of the tuning fork or arranged perpendicular to the vibration direction according to actual detection requirements.

[0011] Furthermore, the cross sections of the sensing electrodes and the exciting electrodes are rectangular.

[0012] Furthermore, the excitation method and detection method include but are not limited to: 1. applying voltage excitation between the excitation electrode and the outer metal-plated electrode, and detecting the inverse piezoelectric response electrical signal between the sensing electrode and the outer metal-plated electrode; 2. directly applying an excitation signal between the excitation electrode and the sensing electrode, testing the impedance response, and grounding the outer metal-plated electrode to shield the stray electric field.

[0013] Furthermore, the resonance frequency of the tuning fork is tuned by the dimensions of the tuning fork length, the geometry of the swing arm, and the thickness of the vibrating swing arm.

[0014] Furthermore, the tuning fork can be used to simultaneously measure the viscosity and density of gases / liquids, or the increase in the effective mass of the tuning fork surface caused by the composition of the solution during electrochemical processes.

[0015] Furthermore, the potential of the metal-plated electrode wrapped around the tuning fork is controllable and can be used to detect the viscosity and density of the electrode-electrolyte interface in electrochemical environments, including but not limited to: corrosion, catalysis, gas sensors, supercapacitors, lithium batteries and new aqueous zinc-ion batteries.

[0016] The present invention adopts the above technical solution. Compared with the traditional two-electrode lithium niobate tuning fork, the present invention innovatively adds a third end electrode as the working electrode of the electrochemical system. The excitation electrode and sensing electrode of the tuning fork are embedded in the interior of the piezoelectric material lithium niobate tuning fork, and the exterior is coated with an inert metal coating. This improves its measurement sensitivity in liquids, ensures the chemical stability of the exposed electrode, and is less prone to electrode corrosion and short circuits. The working electrode can participate in the electrochemical system, monitoring the surface physicochemical processes of the working electrode and the electrolyte, and realizing in-situ coordinated measurement of the rheological properties of liquid media in various complex electrochemical environments. It has great significance and application prospects for early warning of electrochemical failures such as fire and flatulence in battery systems, as well as for analyzing the mechanism of lithium battery capacity decay. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0018] Figure 1 Schematic diagram of the structure of the high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect of the present invention;

[0019] Figure 2 A top view of a high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to the present invention;

[0020] Figure 3 Schematic cross-sectional view of the tuning fork body corresponding to the tuning fork arm of the present invention;

[0021] Figure 4 Schematic diagram of an embodiment of the present invention applied to device measurement of an integrated small liquid pool;

[0022] Figure 5 Schematic diagram of the resonance spectrum of an embodiment of resonance peak measurement and viscosity density fitting in diethyl carbonate organic solvent.

[0023] Figure markings: 1-metal-plated electrode, 2-excitation electrode, 3-sensing electrode, 4-tuning fork body, 5-rubber ring, 6-PVC electrical insulating tape, 71-excitation electrode connection point, 72-sensing electrode connection point, 8-glass protective cover, 9-RBG pin 3pin pin, 10-wire connected to the sensing electrode, 11-wire connected to the metal-plated electrode, 12-wire connected to the excitation electrode, 13-pin pre-insulated terminal. Implementation Method

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0025] like Figures 1 to 5As shown in one of the figures, the present invention discloses a high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect, which includes a tuning fork body 4 formed of piezoelectric material; the tuning fork body 4 includes a tuning fork base and two or more tuning fork arms provided on the tuning fork base; each tuning fork arm is embedded with at least one excitation electrode 2 and at least one sensing electrode 3; all the excitation electrodes 2 are respectively connected to the excitation electrode connection point 71 through a wire; all the sensing electrodes 3 are respectively connected to the sensing electrode connection point 72 through a wire; the excitation electrode connection point 71 and the sensing electrode connection point 72 are respectively provided on the tuning fork base so as to be electrically connected to the external wire; a metal-plated electrode 1 with adjustable electrode potential is provided on the outer peripheral surface of the tuning fork arm of the tuning fork body 4.

[0026] Furthermore, the two tuning fork arms and the tuning fork base are integrally formed.

[0027] Furthermore, the tuning fork body 4 presents a U-shaped structure.

[0028] Furthermore, the tuning fork body 4 is made of lithium niobate (LiNbO3) piezoelectric material; the excitation electrode 2 and the sensing electrode 3 are embedded in the interior of the piezoelectric material LiNbO3 tuning fork, and the metal-plated electrode coated on the outer surface of the tuning fork can be grounded or a polarization voltage (potential is adjustable) can be applied according to the working mode.

[0029] Furthermore, the sensing electrode 3 and the excitation electrode 2 are formed of any metal electrode material (Au / Pt / Cu / Al, etc.), and the metal coating electrode is an inert metal electrode that is resistant to oxidation; or a coating that has an adsorption effect on the gas / liquid medium environment.

[0030] Furthermore, the embedding processing technology of the sensing electrode 3 and the excitation electrode 2 is not limited, and the geometric structure can be adjusted to an embedding structure arranged parallel to the vibration direction of the tuning fork or arranged perpendicular to the vibration direction according to actual detection requirements.

[0031] Furthermore, if Figure 3 As shown, the cross sections of the sensing electrode 3 and the excitation electrode 2 are rectangular.

[0032] Furthermore, the excitation method and detection method include but are not limited to: 1. applying voltage excitation between the excitation electrode 2 and the outer metal-plated electrode, and detecting the inverse piezoelectric response electrical signal between the sensing electrode 3 and the outer metal-plated electrode; 2. directly applying an excitation signal between the excitation electrode 2 and the sensing electrode 3, testing the impedance response, and the outer metal-plated electrode is grounded to shield the stray electric field.

[0033] Furthermore, the resonance frequency of the tuning fork is tuned by the dimensions of the tuning fork length, the geometry of the swing arm, and the thickness of the vibrating swing arm.

[0034] Furthermore, the tuning fork can be used to simultaneously measure the viscosity and density of gases / liquids, or the increase in the effective mass of the tuning fork surface caused by the composition of the solution during electrochemical processes.

[0035] Furthermore, the potential of the outer metal-plated electrode of the tuning fork is controllable, which can be used to detect the viscosity and density of the electrode-electrolyte interface in electrochemical environments, including but not limited to: corrosion, catalysis, gas sensors, supercapacitors, lithium batteries and new aqueous zinc-ion batteries.

[0036] like Figure 4 As shown, the viscosity and density measurements of diethyl carbonate are used as an example. Using the calibrated parameters for real-time nonlinear fitting of the frequency sweep curve, the viscosity and density of the liquid being measured can be measured in real time. The wire 10 of the sensing electrode 3, the wire 11 connected to the inert metal electrode 1, and the wire 12 connected to the excitation electrode 2 are insulated and bundled together with PVC electrical insulation tape 6. A rubber ring 5 is then applied to secure the bundled PVC electrical insulation tape 6 to the outer wall of the glass protective cover 8. Two or more rubber rings 5 ​​are provided to better secure the corresponding wires to the outer wall of the glass protective cover 8. First, use a pipette to inject deionized water into the glass protective cover 8 to clean the tuning fork sensor and prevent internal dirt from shifting the resonant period. Impedance calibration is performed using a resistor of known resistance. The resonance peak of the tuning fork sensor is scanned in air within the calibration frequency range to obtain an air spectrum. Finally, the wire 12 connected to the excitation electrode 2 and the wire 10 of the sensing electrode 3 are connected to the corresponding pins of RBG pin 9 (3-pin). The wire 11 connected to the inert metal electrode 1 is connected to the pin-type pre-insulated terminal 13; the RBG pin 9 and the pin-type pre-insulated terminal 13 are connected to the corresponding positions on the evaluation board respectively. Diethyl carbonate is injected into the glass protective cover 8 with a pipette gun, and a resonance peak scan is performed to obtain the following: Figure 5 Resonance spectrum shown;

[0037] The present invention adopts the above technical solution, and the main body is made of LiNbO3 piezoelectric material, which has better temperature stability and higher mechanical strength than traditional quartz tuning forks, so that it can work under harsh environmental conditions. The present invention has a low phase noise level and is suitable for application scenarios with high requirements for frequency stability and accuracy. The present invention adopts a three-electrode structure to embed the sensing electrode and the excitation electrode inside the LiNbO3 tuning fork to protect them from the influence of the liquid environment, and to achieve online detection of viscosity and density in a conductive solution environment. The overall external exposed surface of the tuning fork with a three-electrode structure of the present invention is coated with an inert metal electrode, and its potential is adjustable. It can be used as a working electrode in an electrochemical system to achieve coordinated detection of mass transfer and charge transfer on the surface of the working electrode in the electrochemical system.

[0038] Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

Claims

1. High-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect, characterized by: The invention comprises a tuning fork body formed of a piezoelectric material; the tuning fork body comprises a tuning fork base and two or more tuning fork arms arranged on the tuning fork base; at least one excitation electrode and at least one sensing electrode are embedded in the interior of each tuning fork arm; all the excitation electrodes are connected to the excitation electrode connection point through wires; all the sensing electrodes are connected to the sensing electrode connection point through wires; the excitation electrode connection point and the sensing electrode connection point are respectively arranged on the tuning fork base so as to be electrically connected to external wires; metal-plated electrodes with adjustable electrode potential are provided on the outer peripheral surfaces of the tuning fork arms corresponding to the tuning fork bodies; the tuning fork body is made of a piezoelectric material of lithium niobate; the excitation electrode and the sensing electrode are embedded in the interior of the tuning fork made of the piezoelectric material of lithium niobate; and the entire exposed outer surface of the tuning fork is coated with an inert metal electrode.

2. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The two tuning fork arms and the tuning fork base are molded in one piece.

3. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The tuning fork body has a U-shaped structure.

4. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The sensing electrode and the excitation electrode are formed of any metal electrode material, and the metal coating electrode is an inert metal that is resistant to oxidation; or a coating that has an adsorption effect on the gas / liquid medium environment.

5. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The sensing electrodes and the excitation electrodes are adjusted to embedded structures arranged parallel to the vibration direction of the tuning fork or perpendicular to the vibration direction according to actual detection requirements.

6. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The excitation and detection methods include:

1. applying voltage excitation between the excitation electrode and the outer metal-plated electrode to detect the inverse piezoelectric response electrical signal between the sensing electrode and the outer metal-plated electrode; 2. applying an excitation signal directly between the excitation electrode and the sensing electrode to test the impedance response, and the outer metal-plated electrode is grounded to shield the stray electric field.

7. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: The resonant frequency of the tuning fork is tuned by the dimensions of the tuning fork length, the geometry of the pendulum arm, and the thickness of the vibrating pendulum arm.

8. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 1, characterized in that: Tuning forks are suitable for simultaneous measurement of viscosity and density of gases / liquids, or for measuring the increase in effective mass on the fork surface caused by solution composition in electrochemical processes.

9. The high-precision electromechanical coupling resonant tuning fork sensor based on piezoelectric or inverse piezoelectric effect according to claim 8, characterized in that: Metal-coated electrodes with adjustable electrode potential are suitable for detecting viscosity and density at the electrode-electrolyte interface in electrochemical environments, including corrosion, catalysis, gas sensors, supercapacitors, lithium batteries, and aqueous zinc-ion batteries.

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