Test fixture for testing electrochemical gas sensor

Abstract

The utility model provides a test fixture for testing an electrochemical gas sensor, which comprises a test bracket and a plurality of sensors positioned on the test bracket, a plurality of test positions and probes for testing the sensors are arranged on the test bracket, the probes are positioned right above the test positions, metal seats are embedded in the test positions, and the metal seats are arranged on the test bracket. The bottom of the sensor is located in the metal base, and the top of the sensor is tightly attached to the probe. The metal seat is embedded in the test position of the test fixture, the probe is arranged on the first PCB, and the sensor is placed in the metal seat and is tightly matched with the probe to realize quick connection of the sensor, so that quick connection test of the sensor can be realized, and the test fixture not only can be used for large-batch test, but also can be used for large-batch test. In addition, the testing is simple and convenient, the traditional mode of realizing signal external transmission backward detection through pin and socket matching and the like is omitted, and the anti-interference capability is strong.

Description

Technical Field

[0001] The utility model belongs to the technical field of sensors, and in particular relates to a test fixture for testing an electrochemical gas sensor. Background Art

[0002] With the development of the times, the Internet of Things (IoT) is increasingly affecting people's lives. The IoT uses sensors based on various principles as the perception layer to obtain underlying information. The indicators detected by these sensors can be physical quantities or chemical quantities. As the eyes and tentacles of the IoT, they provide basic data for the IoT. The IoT has been increasingly used in all levels of production and life. For example, the content of toxic and harmful gases in crowded places such as factories, mining, hospitals, and schools is closely related to people's lives and property. The centralized monitoring of the IoT and big data can play a good early warning role. Among various gas sensors, gas sensors based on electrochemical principles are widely used due to their advantages such as rapid response, high cost performance, and high detection accuracy. Gas sensors based on electrochemical principles usually include a shell, a wire, an electrode, and an electrolyte. The shell is used to provide support for the entire gas sensor, and at the same time, the electrolyte, electrode, and reaction gas chamber are contained inside. The wire is usually made of corrosion-resistant materials such as Pt and Au to transmit the signal of the chemical reaction. The electrode is the place where the chemical reaction occurs. Usually, different electrodes need to be designed for different detection gases to achieve selective detection of the gas. The electrolyte acts as a medium for proton conduction, ensuring the closed loop of the chemical reaction. There are three types of electrolytes commonly used in electrochemical gas sensors: liquid electrolytes, colloidal electrolytes and solid electrolytes. Solid electrolytes are being used by more and more people because of their high reliability and no dryness, leakage and other faults. In current electrochemical gas sensors, the electrodes and electrolytes usually adopt a sandwich structure, that is, the working electrode and the counter electrode are on both sides of the electrolyte. The working electrode is the place where the gas to be measured undergoes a chemical reaction, and the counter electrode is the place where oxygen undergoes a chemical reaction. The anti-interference ability of traditional electrochemical sensors often comes from catalysts, and a certain degree of anti-interference is achieved by the selectivity of the catalyst. However, the types of materials with catalytic functions are limited, and the method of obtaining anti-interference by relying solely on catalysts is often not very effective. In addition, traditional electrochemical sensors often need to use pins and sockets to realize the transmission of signals to the outside and then realize detection. Small-scale experiments are possible, but it is time-consuming and laborious to ship in large quantities. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a test fixture for testing an electrochemical gas sensor which is convenient for testing, in view of the deficiencies existing in the above technical solutions.

[0004] The utility model solves its technical problem by adopting the following technical solution: a test fixture for testing an electrochemical gas sensor, comprising a test bracket and a plurality of sensors located on the test bracket, the test bracket being provided with a plurality of test positions and probes for testing the sensors, the probes being located directly above the test positions, a metal seat being embedded in the test positions, the bottom of the sensor being located in the metal seat, and the top of the sensor being in close contact with the probes.

[0005] Furthermore; the test bracket includes a first PCB circuit board, a second PCB circuit board and a positioning plate, the probe is installed on the first PCB circuit board, the metal seat is embedded in the second PCB circuit board, the positioning plate is installed on the second PCB circuit board, and a plurality of positioning grooves are provided on the positioning plate, and the positions of the positioning grooves correspond to the metal seat, the bottom of the sensor passes through the positioning grooves and abuts against the metal seat, and the top of the sensor fits tightly with the probe.

[0006] Furthermore, the sensor comprises a shell and a membrane electrode assembly for detecting hydrogen, the shell has a cavity inside, and the membrane electrode assembly is arranged in the cavity.

[0007] Furthermore; the membrane electrode assembly includes a solid electrolyte, a working electrode and a counter electrode, and the solid electrolyte, the working electrode and the counter electrode are arranged in the shell from bottom to top in sequence, and an anode separator is placed on the counter electrode. The working electrode and the counter electrode are pressed onto the solid electrolyte by hot pressing, and the edge of the counter electrode protrudes from the edge of the solid electrolyte.

[0008] Furthermore; the shell includes an upper cover, an outer shell and a waterproof breathable membrane for filtering out interfering gases, the upper cover is fixedly connected to the outer shell, an insulating rubber ring is arranged between the upper cover and the membrane electrode assembly, the upper cover is provided with working electrode air holes and counter electrode air holes, and the working electrode air holes and counter electrode air holes correspond to the working electrode and counter electrode, and the waterproof breathable membrane is adhered to the upper cover by 3M glue.

[0009] Furthermore, the diameters of the working electrode air holes and the counter electrode air holes are 0.01-3 mm.

[0010] Furthermore, the thickness of the anode separator is 0.05-0.2 mm.

[0011] Furthermore, the solid electrolyte is a polyvinylidene fluoride membrane or a nafion membrane, and the thickness of the solid electrolyte is 0.005-1 mm.

[0012] Furthermore, the shell and the upper cover are made of metal.

[0013] The beneficial effect of a test fixture for testing an electrochemical gas sensor provided by the utility model is that: by embedding a metal seat into the test position of the test fixture, a probe is arranged on the first PCB circuit board, and the sensor is placed in the metal seat and closely matched with the probe to achieve quick connection of the sensor, a quick connection test of the sensor can be achieved in this way, and the test fixture can not only perform large-scale tests, but also is simple to test, eliminating the traditional method of realizing external transmission of signals through the combination of pins and sockets and the like and then performing shape detection, and has strong anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall structure of a test fixture for testing an electrochemical gas sensor provided by the utility model;

[0015] Figure 2 This is an exploded schematic diagram of the overall structure of the test fixture for testing the electrochemical gas sensor provided by the utility model;

[0016] Figure 3 A schematic diagram of the explosion of a sensor in a test fixture for testing an electrochemical gas sensor provided by the utility model;

[0017] Figure 4 This is a schematic diagram of the structure of a sensor in a test fixture for testing an electrochemical gas sensor provided by the utility model;

[0018] Figure 5 This is a cross-sectional view of a sensor in a test fixture for testing an electrochemical gas sensor provided by the utility model. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0020] See also Figure 1-Figure 5 , which is a test fixture for testing an electrochemical gas sensor provided by the utility model, comprising a test bracket and a plurality of sensors 1 located on the test bracket, wherein the test bracket is provided with a plurality of test positions and probes 21 for testing the sensors 1, wherein the probes 21 are located directly above the test positions, wherein a metal seat 31 is embedded in the test position, wherein the bottom of the sensor 1 is located in the metal seat 31, and the top of the sensor 1 is tightly fitted with the probes 21.

[0021] In this example, the test bracket includes a first PCB circuit board 2, a second PCB circuit board 3 and a positioning plate 4, the probe 21 is mounted on the first PCB circuit board 2, the metal seat 31 is embedded in the second PCB circuit board 3, the positioning plate 4 is mounted on the second PCB circuit board 3, a plurality of positioning grooves 41 are provided on the positioning plate 4, the positions of the positioning grooves 41 correspond to the metal seat 31, the bottom of the sensor 1 passes through the positioning grooves 41 and abuts against the metal seat 31, and the top of the sensor 1 fits tightly with the probe 21. The first PCB circuit board 2 and the second PCB circuit board 3 are used for transmitting signals to the outside.

[0022] In this example, the sensor 1 includes a housing 5 and a membrane electrode assembly 12 for detecting hydrogen. The housing 5 has a cavity 6 inside, and the membrane electrode assembly 12 is disposed in the cavity 6 .

[0023] In this example, the membrane electrode assembly 12 includes a solid electrolyte 121, a working electrode 122 and a counter electrode 123, and the solid electrolyte 121, the working electrode 122 and the counter electrode 123 are arranged in the shell 5 from bottom to top, and an anode isolation membrane 124 is placed on the counter electrode 123. The working electrode 122 and the counter electrode 123 are pressed onto the solid electrolyte 121 by hot pressing, and the edge of the counter electrode 123 protrudes from the edge of the solid electrolyte 121.

[0024] In this example, the shell 5 includes an upper cover 13, an outer shell 11 and a waterproof breathable membrane 16 for filtering out interfering gases. The upper cover 13 is fixedly connected to the outer shell 11. An insulating rubber ring 14 is arranged between the upper cover 13 and the membrane electrode assembly 12. The upper cover 13 is provided with working electrode air holes 131 and counter electrode air holes 132, and the working electrode air holes 131 and counter electrode air holes 132 correspond to the working electrode 122 and counter electrode 123. The waterproof breathable membrane 16 is attached to the upper cover 13 by a 3M adhesive tape 15.

[0025] In this example, the diameters of the working electrode air holes 131 and the counter electrode air holes 132 are 0.01-3 mm.

[0026] In this example, the thickness of the anode separator 124 is 0.05-0.2 mm.

[0027] In this example, the solid electrolyte 121 is a polyvinylidene fluoride membrane or a nafion membrane, and the thickness of the solid electrolyte 121 is 0.005-1 mm.

[0028] In this embodiment, the housing 11 and the upper cover 13 are made of metal.

[0029] The sensor 1 includes a shell 11 and an upper cover 13, which enclose a cavity. The membrane electrode assembly 12 is installed in the cavity. The membrane electrode assembly 12 is composed of a solid electrolyte 121, a working electrode 122 and a counter electrode 123. The membrane electrode assembly 12 is a planar structure, and an anode isolation membrane 124 is placed on the counter electrode 123. The working electrode 122 and the counter electrode 123 are pressed onto the solid electrolyte 121 by hot pressing, wherein the edge of the counter electrode 123 slightly protrudes from the edge of the solid electrolyte 121 by 0.1-0.3mm.

[0030] Specifically, the housing 11 and the upper cover 13 are made of metal, which can be stainless steel, aluminum, tin and other materials, preferably stainless steel; the upper cover 13 is placed in the insulating rubber ring 14 and then the insulating rubber ring 14 is placed on the membrane electrode assembly 12. Among them, the isolation membrane 124 and the insulating rubber ring 14 can be any insulating material, preferably polytetrafluoroethylene, polyvinylidene fluoride, PP, PE and other materials; there are working electrode vents 131 and counter electrode vents 132 on the upper cover 13. During the test, the housing 11 acts as a connecting plate between the metal seat 31 and the counter electrode 123; the upper cover 13 acts as a connecting plate between the probe 21 and the working electrode. The waterproof breathable membrane 16 is pasted on the upper cover 13 by 3M glue 15.

[0031] The following is a detailed description using an electrochemical hydrogen sensor as an example. In this example, the solid electrolyte can be a polyvinylidene fluoride membrane or a nafion membrane with a thickness of 0.005-1 mm; the working electrode 122 and the counter electrode 123 use a porous gas diffusion electrode, wherein the porous gas diffusion electrode includes a substrate and an active catalyst, the substrate can be carbon cloth, carbon paper, carbon fiber, conductive PTFE and other materials, the active catalyst can be a pure noble metal or a supported noble metal catalyst or a mixture of several, if a supported catalyst substrate can be a porous material such as carbon powder, carbon nanotubes, carbon fiber, etc. If a pure noble metal catalyst is used, the active component loading of the catalyst can be 0.1-5 mg / cm2; if a supported noble metal catalyst is used, the active component loading of the catalyst can be 0.05-2 mg / cm2. The working electrode 122 and the counter electrode 123 can use the same symmetrical electrode or an asymmetric electrode, preferably an asymmetric electrode, and the asymmetry can be achieved by using the same loading but different areas, or by using the same area but different loadings. It is preferred to adopt the form of different areas with the same load, the area of ​​the working electrode 122 can be 10%-100% larger than the area of ​​the counter electrode 123; the thickness of the anode isolation membrane 124 is 0.05-0.2mm; the working electrode air vent 131 and the counter electrode air vent 132 on the upper cover 13 can be of the same size or different sizes, preferably different sizes, with a diameter of 0.01-3mm.

[0032] Specifically, the working electrode 122 has an area of ​​0.8 cm2, and is a porous gas diffusion electrode prepared with a supported precious metal catalyst, with a loading of 1.5 mg / cm2; the counter electrode 123 has an area of ​​0.4 cm2, and is a porous gas diffusion electrode prepared with a supported precious metal catalyst, with a loading of 1.5 mg / cm2; the working electrode 122 and the counter electrode 123 are pressed together with the solid electrolyte 121 according to the above requirements to form a membrane electrode assembly 12; the membrane electrode assembly 12 is placed in the shell 5, and the anode separator 124 is placed on the counter electrode 123; the upper cover 13 is placed in the insulating rubber ring 14, and the diameter of the working electrode vent 131 on the upper cover 13 is within the range of 0.01-2 mm, and the diameter of the counter electrode vent 132 is within the range of 0.02-3 mm. The shell 5 is tightened by stamping to complete the assembly of the sensor 1; 3M glue 15 is pasted on the upper cover, and then a waterproof breathable membrane 16 is pasted on it.

[0033] A comparison test was conducted between a hydrogen sensor with a membrane electrode as a core component prepared by a sandwich method on the market and the hydrogen sensor of this embodiment. The test position of the test fixture uses a metal seat 31 in combination with a probe 21 to achieve quick connection. The metal seat 31 is embedded in the test position of the test fixture, and the sensor 1 is placed in the base 31. The shell 5 of the sensor 1 and the connecting plate of the electrode 123 are tightly combined with the metal seat 31 to achieve the connection of the electrode 123; the probe 21 is pressed on the end face of the upper cover 13 of the sensor 1, and the upper cover 13 acts as a connecting plate between the working electrode 122 and the probe 21, thereby achieving the connection of the working electrode 122. In this way, the sensor 1 can be quickly connected and tested. The specific test results are shown in Table 1 below:

[0034] Table 1 Test results data

[0035] <![CDATA[S H2 (uA / ppm)]]> <![CDATA[S CO (uA / ppm)]]> CO cross interference degree (%) Commercially available hydrogen sensors 0.9 0.8 89 Hydrogen sensor of the present invention 0.6 0.03 5

[0036] S in the above table H2 Refers to the sensitivity of the sensor to hydrogen; S CO Refers to the sensor's sensitivity to carbon monoxide.

[0037] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A test fixture for testing an electrochemical gas sensor, comprising a test bracket and a plurality of sensors (1) located on the test bracket, It is characterized in that The test bracket is provided with a plurality of test positions and probes (21) for testing the sensor (1); the probe (21) is located directly above the test position; a metal seat (31) is embedded in the test position; the bottom of the sensor (1) is located in the metal seat (31); and the top of the sensor (1) is tightly fitted with the probe (21).

2. A test fixture for testing an electrochemical gas sensor as claimed in claim 1, It is characterized in that The test bracket comprises a first PCB circuit board (2), a second PCB circuit board (3) and a positioning plate (4); the probe (21) is mounted on the first PCB circuit board (2); the metal seat (31) is embedded in the second PCB circuit board (3); the positioning plate (4) is mounted on the second PCB circuit board (3); a plurality of positioning grooves (41) are provided on the positioning plate (4); the positions of the positioning grooves (41) correspond to the metal seat (31); the bottom of the sensor (1) passes through the positioning grooves (41) and abuts against the metal seat (31); and the top of the sensor (1) is tightly fitted with the probe (21).

3. A test fixture for testing an electrochemical gas sensor as claimed in claim 2, It is characterized in that The sensor (1) comprises a housing (5) and a membrane electrode assembly (12) for detecting hydrogen; the housing (5) has a cavity (6) inside, and the membrane electrode assembly (12) is arranged in the cavity (6).

4. A test fixture for testing an electrochemical gas sensor as claimed in claim 3, It is characterized in that The membrane electrode assembly (12) comprises a solid electrolyte (121), a working electrode (122) and a counter electrode (123); the solid electrolyte (121), the working electrode (122) and the counter electrode (123) are arranged in sequence from bottom to top in the shell (5); an anode separator (124) is placed on the counter electrode (123); the working electrode (122) and the counter electrode (123) are pressed onto the solid electrolyte (121) by hot pressing, and the edge of the counter electrode (123) protrudes from the edge of the solid electrolyte (121).

5. A test fixture for testing an electrochemical gas sensor as claimed in claim 4, It is characterized in that The shell (5) comprises an upper cover (13), an outer shell (11) and a waterproof breathable membrane (16) for filtering out interfering gases. The upper cover (13) is fixedly connected to the outer shell (11). An insulating rubber ring (14) is arranged between the upper cover (13) and the membrane electrode assembly (12). The upper cover (13) is provided with a working electrode air vent (131) and a counter electrode air vent (132). The working electrode air vent (131) and the counter electrode air vent (132) correspond to the working electrode (122) and the counter electrode (123). The waterproof breathable membrane (16) is attached to the upper cover (13) by means of 3M glue (15).

6. A test fixture for testing an electrochemical gas sensor as claimed in claim 5, It is characterized in that The diameters of the working electrode air holes (131) and the counter electrode air holes (132) are 0.01-3 mm.

7. A test fixture for testing an electrochemical gas sensor as claimed in claim 4, It is characterized in that The thickness of the anode separator (124) is 0.05-0.2 mm.

8. A test fixture for testing an electrochemical gas sensor as claimed in claim 4, It is characterized in that The solid electrolyte (121) is a polyvinylidene fluoride membrane or a nafion membrane, and the thickness of the solid electrolyte (121) is 0.005-1 mm.

9. A test fixture for testing an electrochemical gas sensor as claimed in claim 5, It is characterized in that The housing (11) and the upper cover (13) are made of metal.

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