Electrochemical oxygen sensor

Abstract

The present application relates to a kind of electrochemical oxygen sensors, comprising: shell, with first opening, the first opening of shell is covered by upper cover, so that the first cavity between the shell and upper cover is formed, upper cover is provided with air hole passage, the aperture of the air hole passage is 100 ~ 600 μm;Inner groove, with second opening, is arranged in the first cavity, the inner groove is used to accommodate lead block and electrolyte;Working electrode, arranged at the second opening of the inner groove, the working electrode has catalytic layer, the catalytic layer of the working electrode is arranged towards the inner groove so that the catalytic layer is located in the inner groove and is located above the lead block;First pin, arranged on the shell, the first conductive wire is connected between the working electrode and first pin;Second pin, with the first pin being spaced apart, is arranged on the shell, the second conductive wire is connected between the second pin and lead block.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an electrochemical oxygen sensor. Background Technology

[0002] As we all know, oxygen is an essential substance for maintaining human life activities. Human life and production cannot function without oxygen, so monitoring oxygen levels is of particular importance.

[0003] In contemporary society, sensors are the core and most fundamental link of the Internet of Things, serving as a bridge between various types of information and artificial intelligence. Oxygen sensors based on electrochemical principles have high sensitivity, good selectivity, and strong anti-interference capabilities, belonging to an important category of gas sensors. They can be used as an intelligent tool to ensure the safety of people's production and life, and are widely applied in fields such as medicine, wind power, coal mining, and emissions.

[0004] An electrochemical oxygen sensor mainly consists of a housing, a waterproof and breathable membrane, a working electrode, a counter electrode, an electrolyte, conductive wires, pins, and other components. Oxygen enters through the sensor's openings and undergoes an oxidation-reduction reaction on the electrode surface, converting the chemical signal into an electrical signal, thereby enabling the monitoring and assessment of oxygen concentration.

[0005] Existing electrochemical oxygen sensors mainly suffer from the following problems:

[0006] 1) Electrochemical oxygen sensors suffer from severe electrolyte leakage, which corrodes the sensor housing and pins, seriously affecting sensor performance, shortening lifespan, causing sensor malfunction, permanent damage, and even environmental pollution and personal safety issues. Chinese Patent CN 103217464 B, "A Gas Sensor," describes a solution using an inner cup for assembly to reduce leakage. However, the cup top and reservoir cap are open, making sealing impossible. The inner cup bottom is also open, and both bottom filling and heat-press sealing pose a risk of leakage. Furthermore, electrolyte adsorbed on the non-woven fabric inevitably overflows, causing leakage accidents. While the combination of the reservoir cap and inner cup, with bottom filling, is suitable for electrochemical sensors with larger internal electrolytes and smaller counter electrodes (such as CO, H2S, and NO), the solution described in this patent is difficult to implement for electrochemical oxygen sensors with a larger lead block counter electrode.

[0007] 2) Chinese patent CN101339157 B "Electrochemical Gas Sensor" directly passes the conductive wire through the lead block. During the assembly of the electrochemical oxygen sensor, the conductive wire is easily damaged, resulting in assembly failure and serious waste of housing materials, manpower and resources.

[0008] 3) During the assembly of electrochemical oxygen sensors, there is a phenomenon of instantaneous high pressure, which can damage the sensor function. The electrochemical oxygen sensor provided in the method described in Chinese Patent CN 110220952 A "Electrochemical Oxygen Sensor" uses a bottom opening for pressure relief, which can reduce the pressure during sensor assembly to a certain extent, but this method increases the risk of leakage.

[0009] 4) There is a large amount of oxygen in the air environment. The electrochemical oxygen sensor is constantly exposed to the air environment, which causes oxygen to react continuously with the catalyst. This is a consumable process, which accelerates the decay of the lifespan and greatly shortens the lifespan of the electrochemical oxygen sensor.

[0010] 5) In Chinese patent CN 210401307 U "An electrochemical oxygen sensor with replaceable electrolyte", the electrochemical oxygen sensor has an insulating film inside, which achieves the insulation effect between the lead block and the conductive wire. However, this method is effective in the short term. In the long term, the insulating film will be corroded, displaced or worn through by the electrolyte, causing irreparable damage to the oxygen sensor. Summary of the Invention

[0011] The purpose of this invention is to provide an electrochemical oxygen sensor based on existing technologies.

[0012] The purpose of this invention is to overcome the problem of electrolyte leakage in electrochemical oxygen sensors.

[0013] The purpose of this invention is to solve the problem of conductive wire damage during the assembly of electrochemical oxygen sensors.

[0014] The purpose of this invention is to solve the problem of instantaneous pressure generated during the packaging of electrochemical oxygen sensors.

[0015] The purpose of this invention is to solve the problem of lifespan of electrochemical oxygen sensors.

[0016] The purpose of this invention is to solve the problem of corrosion, displacement or wear of the insulating film of electrochemical oxygen sensors by electrolyte.

[0017] To achieve the above objectives, the electrochemical oxygen sensor of the present invention comprises:

[0018] The shell has a first opening, which is covered by a top cover, so that a first cavity is formed between the shell and the top cover. The top cover is provided with an air vent channel with a pore diameter of 100 to 600 μm.

[0019] An inner tank, having a second opening, is disposed within the first cavity; the inner tank is used to accommodate the lead block and the electrolyte.

[0020] A working electrode is disposed at the second opening of the inner tank. The working electrode has a catalytic layer, and the catalytic layer of the working electrode is disposed facing the inner tank such that the catalytic layer is located inside the inner tank and above the lead block.

[0021] A first pin is disposed on the housing, and a first conductive wire is connected between the working electrode and the first pin.

[0022] The second pin is disposed on the housing at a distance from the first pin, and a second conductive wire is connected between the second pin and the lead block.

[0023] Preferably, a second cavity is formed between the top cover and the working electrode, and at least one groove is provided on the outer surface of the inner groove. The second cavity and the groove are connected by an air passage to form a pressure relief air passage.

[0024] Preferably, the outer surface of the inner groove is provided with a first groove and a second groove, the first conductive wire is distributed along the first groove and the upper end of the first conductive wire is sealed through the side wall of the inner groove and connected to the working electrode, and the second conductive wire is distributed along the second groove and the upper end of the second conductive wire is sealed through the side wall of the inner groove and connected to the lead block.

[0025] Preferably, the second cavity is provided with a buffer layer.

[0026] Preferably, the buffer layer is one or more of medical cotton, non-woven fabric, and breathable membrane.

[0027] Preferably, the second cavity is provided with a filter layer, which is located between the buffer layer and the working electrode.

[0028] Preferably, the working electrode has a hydrophobic and breathable membrane, which covers the second opening of the inner tank, and the catalyst layer is attached to the hydrophobic and breathable membrane.

[0029] Preferably, the first cavity is a sealed cavity; the upper cover has an extension that extends into the first cavity, and a sealing ring is provided between the bottom end of the extension and the working electrode; an external breathable membrane is provided outside the air vent channel of the upper cover.

[0030] Preferably, a balance column is provided at the bottom of the inner groove; at least two protrusions distributed along the longitudinal axis of the inner groove are provided on the outer surface of the inner groove; the inner groove is an insulating inner groove.

[0031] Preferably, an adsorption layer is provided between the lead block and the catalytic layer of the working electrode.

[0032] The electrochemical oxygen sensor provided by this invention has an inner tank in which the entire oxidation-reduction reaction takes place, solving the problem of leakage at the bottom of the electrochemical oxygen sensor and improving the internal stability, wear resistance and electrolyte corrosion resistance of the sensor. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the external structure of the electrochemical oxygen sensor of the present invention.

[0034] Figure 2 for Figure 1 Sectional view at point AA.

[0035] Figure 3 This is a schematic diagram of the inner tank structure in the electrochemical oxygen sensor of the present invention.

[0036] Figure 4 The current signal curve of the electrochemical oxygen sensor without buffer cotton is shown.

[0037] Figure 5 This is the current signal curve of the electrochemical oxygen sensor of the present invention with buffer cotton.

[0038] Figure 6 This is a microstructure diagram of the cushioning cotton. Detailed Implementation

[0039] The following disclosure provides many different embodiments or examples to illustrate different components of embodiments of the present invention. Specific examples of the components and their arrangement will be disclosed below to simplify the description of this disclosure. Of course, these specific examples are not intended to limit this disclosure.

[0040] like Figures 1-6The image shows an embodiment of the electrochemical oxygen sensor provided by the present invention. The sensor includes: a housing 1 with a first opening, the first opening of which is covered by a top cover 2, forming a first cavity between the housing 1 and the top cover 2; the top cover 2 having pore channels 7 with a pore diameter of 100–600 μm; an inner groove 3 with a second opening disposed within the first cavity, the inner groove 3 accommodating a lead block 4 and an electrolyte; and a working electrode 5 disposed at the second opening of the inner groove 3, the working electrode 5 having a catalytic layer facing the inner groove. The catalyst layer is positioned within the inner tank 3 and above the lead block 4. A first pin 8 is disposed on the housing 1, and a first conductive wire 10 connects the working electrode 5 and the first pin 8, i.e., the upper and lower ends of the first conductive wire 10 are connected to the working electrode 5 and the first pin 8, respectively. A second pin 9 is disposed on the housing 1 at a distance from the first pin 8, and a second conductive wire 11 connects the second pin 9 and the lead block 4, i.e., the upper and lower ends of the second conductive wire 11 are connected to the top of the lead block 4 and the second pin 9, respectively. The pin shape can be any of the following: "T" shape, hammer shape, or sickle shape. The pin material can be one of the following elements or alloys: Pt, Ag, Au, Ni, Cu, Sn, Fe, Al, Ru, and Zn. The pins can be embedded at the bottom of the housing 1.

[0041] The cavity formed by the shell 1 and the top cover 2 is a sealed cavity. For example, it can be sealed by adhesive bonding or ultrasonic welding.

[0042] The air vent 7 of the upper cover 2 can be set in the middle of the upper cover 2. The air vent 7 is a capillary micropore with a preferred pore size of 100-600μm. It can allow inert gases and oxygen to pass through, and can reduce the intake air pressure, ensuring the sensor sensitivity while improving the sensor lifespan, and can also reduce the instantaneous pressure of the sensor.

[0043] An external breathable membrane 6 is provided outside the air vent channel 7 of the upper cover 2. This external breathable membrane 6 has the function of waterproofing and dustproofing, preventing water droplets and dust from clogging the air vent channel 7. The external breathable membrane 6 can be a composite membrane made of one or more materials such as PTFE, PVDF, PP, or PC.

[0044] In the embodiments provided by this invention, an inner tank is provided inside the housing, and a lead block, the catalytic material of the working electrode, and the electrolyte are placed in the inner tank. That is, the entire redox reaction takes place in the inner tank, which effectively improves the utilization rate of the chemical reaction and avoids direct contact between the electrolyte and the housing 1. This effectively prevents the electrolyte from seeping out from the gap between the pin and the housing 1, thereby avoiding the risk of leakage and solving the problem of leakage at the bottom of the electrochemical oxygen sensor. The upper surface of the lead block is flat and free from obvious unevenness, oil stains, or other impurities. The electrolyte can be one or more of CH3COOK, CH3COONa, Mg(CH3COO)▪4H2O, (CH3COO)2Ca, and (CH3COO)2Pb.

[0045] The inner groove 3 can be made of ABS plastic, which has certain mechanical toughness and strength, and is also insulating, thus insulating the conductive wire from the lead block and improving the internal stability, wear resistance, and resistance to electrolyte corrosion of the sensor. Furthermore, the housing and top cover can also be made of ABS plastic to provide mechanical toughness and strength.

[0046] The bottom of the inner groove 3 is provided with a balance column 35. The balance column 35 can be directly inserted into the shell 1 or glued to stabilize it, thereby improving the stability of the inner groove and ensuring the consistency of the relative position between the inner groove and the shell. The outer surface of the inner groove 3 is also provided with at least two parallel protrusions 34.

[0047] A second cavity is formed between the upper cover 2 and the working electrode 5. A pair of grooves 31, namely a first groove and a second groove, are provided on the outer surface of the inner groove 3. On the one hand, the second cavity and the grooves 31 are connected by an air passage to form a pressure relief air passage. On the other hand, the first conductive wire 10 is distributed along the first groove and the upper end of the first conductive wire 10 is sealed through the side wall of the inner groove 3 and connected to the working electrode 5. The second conductive wire 11 is distributed along the second groove and the upper end of the second conductive wire 11 is sealed through the side wall of the inner groove 3 and connected to the lead block 4.

[0048] In the embodiments provided by the present invention, such as Figure 3 As shown, the first and second grooves are arranged parallel to each other along the longitudinal axis of the inner groove, allowing the first and second conductive wires to pass through respectively. This prevents damage to the conductive wires during sensor assembly, making assembly more convenient, faster, and with a higher success rate, while also providing some protection for the conductive wires. The conductive wires can be one or more elements or alloys selected from Au, Ag, Ni, Pt, Sn, Zn, Ru, and Pb.

[0049] In the embodiments provided by the present invention, the upper end of the conductive wire passes through the side wall of the inner groove in a sealed manner. For example, it can be fixed and pass through the side wall of the inner groove by embedding or injection molding, so that the inner groove 3 has a first connecting part 32 and a second connecting part 33, and the connection between the conductive wire and the side wall of the inner groove, that is, the first connecting part 32 and the second connecting part 33, are sealed without gaps.

[0050] The second cavity is provided with a buffer layer 14. The buffer layer 14 is one or more of medical cotton, non-woven fabric, and breathable membrane, serving a gas buffering function. Figure 4 and Figure 5 The figures show the current signal curves of the electrochemical oxygen sensor with and without buffer cotton. When the sensor is filled with buffer cotton, the current of the electrochemical sensor will experience a sudden change when the sensor is ventilated or the ambient air pressure is unstable. This will cause current instability, affect the stability of the sensor performance, or lead to false alarms, or even permanent damage to the electrochemical oxygen sensor.

[0051] In an embodiment of the present invention, the upper cover 2 has a cavity below the air vent channel, and the cavity contains a buffer layer, such as... Figure 6 As shown, the internal structure of the buffer layer is made of fibers and has a dense three-dimensional cross-linked network structure with certain gaps. This unique structure can reduce the inlet air pressure of the sensor, thereby effectively avoiding instantaneous current surges caused by excessive or unstable inlet air pressure. This allows the sensor to output a stable current signal, ensuring the internal stability and long lifespan of the sensor.

[0052] In the embodiments provided by the present invention, the combination of a buffer layer and a capillary micropore air channel can solve the problem of sudden current change, enabling the sensor to output a stable current signal, ensuring the internal stability and long life of the sensor. If a larger air inlet is used, the technical effect will be weakened.

[0053] The second cavity is provided with a filter layer 15, which is located between the buffer layer 14 and the working electrode 5. The filter layer 15 can filter out impurity gases such as hydrogen sulfide, sulfur dioxide, and nitrogen oxides, effectively solving the anti-interference problem of the electrochemical oxygen sensor.

[0054] The working electrode 5 has a hydrophobic and breathable membrane that covers the second opening of the inner tank. The catalyst layer is attached to the hydrophobic and breathable membrane. Thus, the catalyst layer, electrolyte, end of conductive wire, and lead block of the working electrode are all in the inner tank 3, and the entire electrochemical reaction takes place in the inner tank 3. The catalyst material of the catalyst layer includes one or more elemental metals or alloys selected from Pt, Pd, Au, Ag, Ir, Ru, Sn, etc., and supports one or more conductive agents selected from carbon powder, graphene, activated carbon, polyaniline, diamond, etc.

[0055] The vent channel forms a gas pressure relief channel through the hydrophobic and breathable membrane, filter layer, buffer layer on the working electrode and the groove on the outer surface of the inner tank. This can effectively solve the problem of excessive instantaneous pressure during sensor assembly and prevent functional damage to the electrochemical oxygen sensor during assembly.

[0056] The upper cover 2 has an extension that extends into the first cavity, and a sealing ring 12 is provided between the bottom end of the extension and the working electrode. The sealing ring can be made of one of nitrile rubber, fluororubber, silicone rubber, or EPDM.

[0057] Specifically, the hydrophobic and breathable membrane of the working electrode covers the second opening of the inner tank, and a sealing ring is used to seal the edge of the membrane to prevent electrolyte from overflowing and completely block the liquid in the inner tank, effectively solving the serious leakage problem of the electrochemical oxygen sensor.

[0058] In the embodiments provided by the present invention, the catalyst layer of the working electrode is located above the lead block in non-direct contact. An adsorption layer 13 is provided between the lead block 4 and the catalyst layer of the working electrode 5. The adsorption layer 13 is also located in the inner tank. The adsorption layer can be made of non-woven fabric, etc. Non-woven fabric has strong chemical corrosion resistance, strong toughness, and is not easily worn, torn, or broken. It absorbs excess electrolyte, prevents electrolyte overflow, ensures electrolyte balance in the inner tank, and improves the stability of the electrochemical oxygen sensor. Furthermore, the combination of the inner tank and the non-woven fabric adsorption layer insulates the conductive wire from the lead block.

[0059] like Figure 2 As shown, the adsorption layer 13 is sandwiched between the working electrode 5 and the lead block 4. The catalyst layer in the working electrode 5 is attached to the hydrophobic breathable membrane. The sealing ring 12 is located between the upper cover 2 and the working electrode 5, fitting tightly together. The lower part is supported by the inner groove 3 and the lead block 4. The second opening of the inner groove has multiple parts such as the upper cover, working electrode, sealing ring, adsorption layer and buffer layer working together to form a sealing system, which can effectively prevent electrolyte leakage. With double insurance from the top and bottom, it effectively solves the problem of leakage in electrochemical oxygen sensors.

[0060] In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. An electrochemical oxygen sensor, characterized in that, include: The housing has a first opening, which is covered by a top cover, forming a first cavity between the housing and the top cover. The first cavity is a sealed cavity. The top cover is provided with an air vent channel, the vent channel having a pore diameter of 100–600 μm. An inner tank, having a second opening, is disposed within the first cavity; the inner tank is used to accommodate the lead block and the electrolyte. A working electrode is disposed at the second opening of the inner tank. The working electrode has a catalytic layer, and the catalytic layer of the working electrode is disposed facing the inner tank such that the catalytic layer is located inside the inner tank and above the lead block. A first pin is disposed on the housing, and a first conductive wire is connected between the working electrode and the first pin. The second pin is disposed on the housing at a distance from the first pin, and a second conductive wire is connected between the second pin and the lead block; a second cavity is formed between the top cover and the working electrode, and at least one groove is provided on the outer surface of the inner groove, and the second cavity and the groove are connected by an air passage to form a pressure relief air passage. The second cavity is provided with a buffer layer; The working electrode has a hydrophobic and breathable membrane, which covers the second opening of the inner tank, and the catalyst layer is attached to the hydrophobic and breathable membrane.

2. The electrochemical oxygen sensor according to claim 1, characterized in that, The outer surface of the inner groove is provided with a first groove and a second groove. The first conductive wire is distributed along the first groove and its upper end is sealed through the side wall of the inner groove and connected to the working electrode. The second conductive wire is distributed along the second groove and its upper end is sealed through the side wall of the inner groove and connected to the lead block.

3. The electrochemical oxygen sensor according to claim 1, characterized in that, The buffer layer is one or more of medical cotton, non-woven fabric, and breathable membrane.

4. The electrochemical oxygen sensor according to claim 1, characterized in that, The second cavity is provided with a filter layer, which is located between the buffer layer and the working electrode.

5. The electrochemical oxygen sensor according to claim 1, characterized in that, The top cover has an extension that extends into the first cavity, and a sealing ring is provided between the bottom end of the extension and the working electrode; an external breathable membrane is provided outside the air vent channel of the top cover.

6. The electrochemical oxygen sensor according to claim 1, characterized in that, The bottom of the inner groove is provided with a balance column; the outer surface of the inner groove is provided with at least two protrusions distributed along the longitudinal axis of the inner groove; the inner groove is an insulating inner groove.

7. The electrochemical oxygen sensor according to claim 1, characterized in that, An adsorption layer is provided between the lead block and the catalytic layer of the working electrode.

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