Electrochemical gas sensor, gas detection device, and gas detection system

Abstract

To provide an electrochemical gas sensor including a simple signal extraction structure.SOLUTION: An electrochemical gas sensor 1 includes: a base plate 10; a gas detection unit 2 that is placed on a first face 10a of the base plate 10; a cover 40 that covers the gas detection unit 2; a wiring 11 that is connected to the gas detection unit 2, and part of which is exposed from the cover 40. The portion of the wiring 11 exposed from the cover 40 is formed with a connection portion 15 to be connected to external wiring or an external terminal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electrochemical gas sensor, a gas detection device using the sensor, and a gas detection system using the gas detection device. [Background technology]

[0002] Conventionally, electrochemical gas sensors equipped with a catalytic layer and an electrolyte layer have been known. In electrochemical gas sensors, for example, a working electrode (sensing electrode) made of a catalytic layer and a counter electrode are connected via an external circuit. When a gas to be detected, such as carbon monoxide, flows into the sensor, an oxidation reaction of carbon monoxide occurs at the working electrode, and the concentration of the gas can be detected by measuring the short-circuit current that occurs during this reaction.

[0003] Patent Document 1 discloses an electrochemical gas sensor including a polymer solid electrolyte membrane, a sensing electrode, a counter electrode, and a gas diffusion layer. The sensor in Patent Document 1 has a laminated structure in which a sensing electrode is formed on one side of a solid electrolyte membrane and a counter electrode is formed on the other side, and the solid electrolyte membrane is sandwiched between gas diffusion layers. This laminated structure functions as a gas detection unit, and the sensor is constructed by being sandwiched between a sealing body and a metal can. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 047316 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, electrochemical gas sensors generate an electrical signal when they detect a target gas, and this electrical signal must be extracted from the gas detection unit. However, electrochemical gas sensors are required to be small and low-cost, so it is undesirable to use a complex signal extraction structure. [Means for solving the problem]

[0006] The electrochemical gas sensor according to the present disclosure comprises a substrate including a first surface and a second surface, a gas detection unit disposed on the first surface of the substrate, a cover covering the gas detection unit, and wiring connected to the gas detection unit and a portion of which is exposed from the cover, wherein the portion of the wiring exposed from the cover has a connection portion formed thereon that is connected to an external wiring or an external terminal.

[0007] A gas detection device according to the present disclosure includes the electrochemical gas sensor and a housing that houses the electrochemical gas sensor.

[0008] A gas detection system according to the present disclosure includes the gas detection device and a receiving device that receives the detection result of the gas detection device. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, an electrochemical gas sensor having a simple signal extraction structure can be provided, which can, for example, reduce the size and cost of the sensor. Furthermore, the electrochemical gas sensor according to the present disclosure can be easily attached to a gas detection device such as a smoke detector. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a state in which an electrochemical gas sensor according to an embodiment is mounted on a circuit board. FIG. [Figure 2] 1 is a perspective view of an electrochemical gas sensor according to an embodiment; [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB in FIG. 2. [Figure 5] FIG. 10 is a diagram showing a modified example of the electrochemical gas sensor. [Figure 6] FIG. 10 is a diagram showing a modified example of the electrochemical gas sensor. [Figure 7]1 is a block diagram showing a configuration of a gas detection system according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, with reference to the drawings, embodiments of an electrochemical gas sensor, a gas detection device, and a gas detection system according to the present disclosure will be described in detail. Note that the embodiments described below are merely examples, and the present disclosure is not limited thereto. Furthermore, selective combinations of multiple embodiments and variations described below are also included in the present disclosure.

[0012] FIG. 1 is a diagram showing an electrochemical gas sensor 1 according to an embodiment mounted on a circuit board 112. As shown in FIG. 1, the electrochemical gas sensor 1 includes a substrate 10, a gas detection unit 2 (see FIG. 2 described later) disposed on the surface of the substrate 10, and a cover 40 that covers the gas detection unit 2. The electrochemical gas sensor 1 further includes a wiring 11 connected to the gas detection unit 2. A portion of the wiring 11 is exposed from the cover 40 and functions as a wiring for extracting a signal generated in the gas detection unit 2. As will be described in more detail later, a connection portion 15 is formed on the portion of the wiring 11 exposed from the cover 40, which is connected to an external wiring or an external terminal. The wiring 11 is, for example, a conductor layer formed on the surface of the substrate 10, and is specifically a metal layer or the like.

[0013] The substrate 10 has a plurality of protrusions 14 protruding from the cover 40. In the example shown in FIG. 1, the protrusions 14 extend from both longitudinal ends of the cover 40, which has a rectangular shape in a plan view, to the outside of the cover 40. In this specification, "plan view" means a view of the electrochemical gas sensor 1 and its components as seen from the first surface 10a (see FIG. 3) of the substrate 10. Two protrusions 14 extend from one longitudinal end of the cover 40, and one protrusion 14 extends from the other longitudinal end. The three protrusions 14 are formed parallel to one another along the longitudinal direction of the cover 40, and each has a wiring 11 and a connection portion 15. The wiring 11 extends along the longitudinal direction of each protrusion 14, and the connection portion 15 is formed at the tip of each protrusion 14.

[0014] The electrochemical gas sensor 1 is attached to a circuit board 112 by utilizing a protrusion 14. The circuit board 112 has conductive pins 113 standing on the surface of the board. The pins 113 are, for example, external terminals electrically connected to other electronic devices that constitute the circuit board 112, and have a substantially cylindrical shape. The circuit board 112 also has a recess 114 into which the cover 40 of the electrochemical gas sensor 1 fits. The recess 114 is formed by cutting out an end of the circuit board 112 in a substantially U-shape in plan view, and is large enough to accommodate the cover 40.

[0015] The electrochemical gas sensor 1 is mounted on the circuit board 112 by connecting the connection portions 15 formed on the protruding portions 14 to the pins 113. In the example shown in Fig. 1, the connection portions 15 include through holes that are semicircular in plan view, and the pins 113 are inserted into the through holes of the connection portions 15. Three pins 113 are provided on the periphery of the recess 114 so that they can be inserted into the connection portions 15 of the protruding portions 14 when the electrochemical gas sensor 1 is accommodated in the recess 114.

[0016] The connecting portion 15 constitutes a part of the wiring 11, and has a conductor layer formed on the periphery and inner surface of the through hole. The conductor layer formed on the inner surface of the connecting portion 15 abuts on the outer surface of the pin 113 and is electrically connected to the pin 113. The connecting portion 15 and the pin 113 may be soldered. A signal generated in the gas detection unit 2 is transmitted to the connecting portion 15 via the wiring 11, and then transmitted to the pin 113 via the connecting portion 15.

[0017] FIG. 2 is a perspective view of the electrochemical gas sensor 1. In the example shown in FIG. 2, the connection part 15 includes a through-hole that is circular in plan view, but the other configurations are the same as those of the example shown in FIG. 1. As shown in FIGS. 1 and 2, the through-hole of the connection part 15 may be semicircular or circular in plan view. The shape of the connection part 15 can be changed depending on the shape of the external wiring or external terminal to which the signal from the gas detection part 2 is output, etc.

[0018] 2, the substrate 10 of the electrochemical gas sensor 1 includes a base portion 13 that is rectangular in plan view and on which the gas detection portion 2 is disposed, and three protrusions 14 that protrude from opposing short sides of the base portion 13. The substrate 10 is disposed so that the longitudinal direction of the base portion 13 is parallel to the longitudinal direction of the cover 40. The substrate 10 is substantially flat except for, for example, portions where the gas introduction hole 12 (first gas introduction hole) and the connection portion 15 are formed, and the base portion 13 and each of the protrusions 14 are formed on the same plane.

[0019] In this embodiment, two protrusions 14a and 14b protrude from one short side of the base portion 13, and one protrusion 14c protrudes from the other short side of the base portion 13. As will be described in detail later, the wiring 11a formed on the protrusion 14a functions as a wiring for the working electrode, the wiring 11b formed on the protrusion 14b functions as a wiring for the counter electrode, and the wiring 11c formed on the protrusion 14c functions as a wiring for the reference electrode. Connection portions 15a, 15b, and 15c are formed at the tips of the protrusions 14a, 14b, and 14c, respectively. The protrusions 14a, 14b, and 14c have the same shape and size, but may have different shapes and sizes.

[0020] Protrusions 14a and 14b each protrude from between the center and both ends of one short side of base portion 13, and protrusion 14c protrudes from the center of the other short side of base portion 13. The multiple protrusions 14 protrude in two directions from opposite ends of cover 40. The multiple protrusions 14 may protrude in three directions from cover 40, for example, but connecting them to circuit board 112 is easier when the protrusions 14 protrude in two directions. Note that protrusions 14a and 14c, or protrusions 14b and 14c, may protrude in the same direction.

[0021] The cover 40 is composed of a first cover 41 and a second cover 42. Each protrusion 14 of the substrate 10 is sandwiched between the first cover 41 and the second cover 42. Each protrusion 14 protrudes from between the first cover 41 and the second cover 42 to the outside of the cover 40. In this embodiment, the cover 40 covers the entire substrate 10 except for the protrusions 14. The cover 40 covers the entire gas detection unit 2 and also covers the short side surfaces of the substrate 10.

[0022] The first cover 41 and the second cover 42 are hard covers formed in the shape of a rectangular cylinder with a bottom, and the open ends of the covers are overlapped with the substrate 10 sandwiched between them to form the rectangular parallelepiped cover 40. The first cover 41 and the second cover 42 accommodate the portions of the substrate 10 other than the protrusion 14 and are connected to each other. At least one of the first cover 41 and the second cover 42 has a recess formed therein for the protrusion 14 to pass through. A sealing member for sealing the gap between the cover 40 and the protrusion 14 may be provided, or an adhesive may be applied.

[0023] Fig. 3 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 4 is a cross-sectional view taken along line BB in Fig. 2. As shown in Figs. 3 and 4, the electrochemical gas sensor 1 includes wiring 11 formed on a first surface 10a of a substrate 10, a catalyst layer 20, and an electrolyte layer 30. The substrate 10 has a gas inlet hole 12 that connects the first surface 10a and the second surface 10b. The catalyst layer 20 is formed on the first surface 10a of the substrate 10 so as to cover a portion of the wiring 11 and the gas inlet hole 12. The electrolyte layer 30 is formed on the first surface 10a of the substrate 10 so as to be in contact with the catalyst layer 20.

[0024] The electrochemical gas sensor 1 includes, as the catalyst layer 20, a catalyst layer 20a that serves as a working electrode and a catalyst layer 20b that serves as a counter electrode. The catalyst layers 20a and 20b are formed on the first surface 10a of the substrate 10 so as not to contact each other. The catalyst layer 20 preferably further includes a catalyst layer 20c that serves as a reference electrode. The wiring 11 includes a wiring 11a that corresponds to the catalyst layer 20a (working electrode), a wiring 11b that corresponds to the catalyst layer 20b (counter electrode), and a wiring 11c (see FIG. 2) that corresponds to the reference electrode. Similarly, the wirings 11a, 11b, and 11c are formed on the first surface 10a of the substrate 10 so as not to contact each other.

[0025] In the electrochemical gas sensor 1, a laminated structure including wiring 11 formed directly on the first surface 10a of the substrate 10, a catalyst layer 20, and an electrolyte layer 30 functions as the gas detection unit 2. The catalyst layer 20a, which functions as a working electrode, and the catalyst layer 20b, which functions as a counter electrode, are arranged via the electrolyte layer 30 in an ionically conductive manner and are electrically connected via an external circuit (not shown). The working electrode is an electrode into which the gas to be detected flows and is also called the sensing electrode. The electrolyte layer 30 needs to be in contact with at least a portion of the catalyst layers 20a and 20b. Furthermore, if the catalyst layer 20c is formed, the electrolyte layer 30 needs to be in contact with at least a portion of the catalyst layers 20a, 20b, and 20c.

[0026] As will be described in more detail later, forming the catalyst layer 20 directly on the surface of the substrate 10, on which the wiring 11 and the gas inlet hole 12 are formed, and then forming the electrolyte layer 30 directly on the catalyst layer 20, strengthens the adhesion of the layers that make up the gas detection unit, thereby reducing the contact resistance of the laminated structure. Furthermore, with the electrochemical sensor 1, there is no need to press the gas detection unit 2 to keep the contact resistance low, eliminating the need for special fastening jigs and reducing the variation in contact resistance. This means that the sensor's resistance value decreases and becomes more stable. This results in improved sensor reliability, leading to higher sensitivity, smaller size, and lower cost.

[0027] The electrochemical gas sensor 1 detects the gas concentration by introducing a gas to be detected into the working electrode, oxidizing or reducing the gas molecules on the working electrode, and measuring the change in current or potential associated with this redox reaction. While the electrochemical gas sensor 1 may be a potential detection type, this embodiment illustrates a current detection type sensor. When gas molecules are oxidized or reduced at the working electrode, electrons are generated or consumed, causing a current to flow between the working electrode and the counter electrode. This current value is proportional to the gas concentration, so the gas concentration can be detected by measuring the current value. Ions generated by the redox reaction at the working electrode and counter electrode migrate between the working electrode and the counter electrode via the electrolyte layer 30.

[0028] As described above, the electrochemical gas sensor 1 includes the catalyst layer 20a functioning as a working electrode, the catalyst layer 20b functioning as a counter electrode, and the catalyst layer 20c functioning as a reference electrode. The reference electrode is an electrode that serves as a reference when controlling and measuring the potential of the working electrode, and is also called a reference electrode. The working electrode is connected to the reference electrode via an external circuit, and is configured to maintain a constant potential relative to the reference electrode via the external circuit. The potential of the working electrode is maintained at a potential that can oxidize the target gas, for example.

[0029] In the following, carbon monoxide (CO) will be used as an example of a gas to be detected. However, sensors to which the configuration of the electrochemical gas sensor according to the present disclosure can be applied are not limited to carbon monoxide sensors. The configuration of the electrochemical gas sensor according to the present disclosure can be widely applied, particularly to electrochemical gas sensors that use solid electrolyte membranes, and can also be applied to sensors that detect gases such as hydrogen sulfide (HS), nitric oxide (NO), nitrogen dioxide (NO), sulfur dioxide (SO), ozone (O), and ammonia (NH).

[0030] When the gas to be detected by the electrochemical gas sensor 1 is CO, an oxidation reaction of CO shown in formula (1) occurs at the working electrode. CO+H2O→CO2+2H + +2e - ···(1) CO that flows into the working electrode reacts with water molecules to generate CO2 and protons (H + ) and electrons are generated. The protons move to the counter electrode via the electrolyte layer 30, and the electrons move to the counter electrode via an external circuit. At the counter electrode, the reaction shown in formula (2) occurs. 1 / 2 O2+2H + +2e - →H2O···(2) The protons and electrons generated at the working electrode react with oxygen in the air at the counter electrode to produce water. At this time, the current flowing in the external circuit is proportional to the amount of CO2 flowing into the working electrode, so the CO2 concentration can be detected by measuring this current.

[0031] The electrochemical gas sensor 1 has a structure in which the interior of the sensor, in which the gas detection unit 2 is formed, is sealed by a cover 40. A first cover 41 constituting the cover 40 is disposed on the first surface 10a of the substrate 10 and entirely covers the catalyst layer 20 and the electrolyte layer 30. A second cover 42 is disposed on the second surface 10b of the substrate 10. The first cover 41 is made of a material with low gas permeability that can block gases such as CO and water vapor, and seals the gas detection unit. The second cover 42 is also made of a material with low gas permeability, but has a gas inlet hole 43 formed in the second cover 42. CO, the gas to be detected, is introduced into the gas detection unit 2 only through the gas inlet hole 43 in the second cover 42 and the gas inlet hole 12 in the substrate 10.

[0032] In the electrochemical gas sensor 1, an internal space is formed between the electrolyte layer 30 and the first cover 41. That is, there is a gap between the gas detection unit 2 and the first cover 41, and the gas detection unit 2 is not pressed by the first cover 41. The electrochemical sensor 1 further includes a humidity control member 60 disposed in this internal space. As described above, in the electrochemical sensor 1, the solid electrolyte membrane needs to contain a certain amount of moisture in order to function, and the amount of moisture in the solid electrolyte membrane needs to be controlled. The humidity control member 60 serves to adjust the amount of moisture contained in the solid electrolyte membrane. The humidity control member 60 serves to adjust the amount of moisture contained in the solid electrolyte membrane.

[0033] The humidity control member 60 is housed in the first cover 41 without contacting the catalyst layer 20 and electrolyte layer 30 that constitute the gas detection unit 2. In this embodiment, the humidity control member 60 is layered on the electrolyte layer, but the humidity control member 60 may be placed in a location where it does not overlap with the electrolyte layer 30, such as around the gas detection unit 2. In addition, a gap exists between the humidity control member 60 and the cover 40. The humidity control member 60 may expand in volume when it absorbs moisture, but if a gap exists between the humidity control member 60 and the cover 40, this gap can absorb the volumetric expansion of the humidity control member 60. As a result, the structure of the sensor is stabilized, leading to improved reliability.

[0034] The electrochemical sensor 1 further includes a breathable partition layer 70 disposed between the electrolyte layer 30 and the humidity control member 60. When the humidity control member 60 is in contact with the electrolyte layer 30, it is difficult to appropriately adjust the amount of moisture contained in the solid electrolyte membrane. By interposing the partition layer 70 between the electrolyte layer 30 and the humidity control member 60, it becomes easier to adjust the amount of moisture contained in the solid electrolyte membrane, leading to improved reliability and sensitivity of the sensor. The partition layer 70 is preferably permeable to water vapor.

[0035] The electrochemical gas sensor 1 further includes activated carbon 80 housed within the second cover 42. An internal space exists between the substrate 10 and the second cover 42, and the activated carbon 80 is disposed in this internal space. The activated carbon 80 adsorbs highly polar gases such as SOx and NOx, and allows CO, the target gas to be detected, to pass through. By providing the activated carbon 80 in the CO introduction path and trapping non-target gases, it is possible to achieve further improvements in reliability and sensitivity.

[0036] The first cover 41 and the second cover 42 accommodate the entire base portion 13 of the substrate 10 and the root portion of the protrusion 14, and are connected to each other. The first cover 41 and the second cover 42 are formed, for example, in the shape of a rectangular tube with a bottom, and are fixed to each other with their open ends overlapping each other using adhesives, screws, a locking structure, or by welding or the like. As shown in FIG. 3 , the first cover 41 and the second cover 42 may sandwich an end along a long side of the base portion 13. A sealing member 50 may be disposed between the substrate 10 and the first cover 41 and second cover 42.

[0037] The structures of the substrate 10, catalyst layer 20, electrolyte layer 30, cover 40, humidity control member 60, and partition layer 70 that constitute the electrochemical gas sensor 1 will be described in detail below.

[0038] [substrate] As described above, the substrate 10 is an insulating base material including the base portion 13 on which the gas detection portion 2 is formed and a plurality of protrusions 14 protruding from the base portion 13, and the base portion 13 and the plurality of protrusions 14 are integrally molded. The protrusions 14 are formed parallel to each other and extend in the longitudinal direction of the base portion 13. Each of the protrusions 14 has a constant width over its entire length and is formed into a rectangular shape in a plan view. The shape of the substrate 10 in a plan view is not particularly limited and can be changed as appropriate depending on the shape of the electrochemical gas sensor 1, etc.

[0039] The substrate 10 has wiring 11 that functions as wiring and a gas inlet hole 12 that connects the first surface 10a and the second surface 10b. The substrate 10 is made of a material similar to that used for conventionally known printed wiring boards, such as epoxy resin or polyphenylene ether. The substrate 10 may be a dedicated substrate for the electrochemical gas sensor 1, or may be a printed wiring board on which other electronic components are mounted. In this embodiment, the substrate 10 functions as a support member for the gas detection unit 2, and the protrusion 14 of the substrate 10 functions as a fixing portion for the circuit board 112.

[0040] The gas inlet holes 12 of the substrate 10 are preferably formed at positions overlapping with the gas detection unit 2, particularly at positions overlapping with the catalyst layer 20a that functions as the working electrode, and function as paths for introducing gas into the catalyst layer 20a. In other words, the catalyst layer 20a is formed in the region of the first surface 10a of the substrate 10 where the gas inlet holes 12 are formed. In this embodiment, the multiple gas inlet holes 12 are formed only at positions overlapping with the catalyst layer 20a. That is, in the region of the first surface 10a covered by the first cover 41, there are no through holes for wiring such as through holes, and no through holes other than the gas inlet holes 12 are formed.

[0041] The electrochemical gas sensor 1 is configured so that CO flows into the internal space surrounded by the substrate 10 and the first cover 41 only through the gas inlet 12, and the amount of CO acting on the catalyst layer 20a is controlled. Therefore, the CO concentration can be accurately determined from the proportional relationship between the amount of CO inflow and the current value. The gas inlet 12 is, for example, a through-hole that is circular in plan view.

[0042] The gas introduction holes 12 have a diameter of, for example, 0.05 to 1 mm, or 0.1 to 0.5 mm. The opening area of ​​the gas introduction holes 12 is not particularly limited, but is preferably large enough to prevent the material constituting the catalyst layer 20 from flowing into the gas introduction holes 12 when the material is applied to the first surface 10a of the substrate 10. That is, it is preferable that a large number of gas introduction holes 12 with small opening areas are formed in the substrate 10. However, the number of gas introduction holes 12 is not particularly limited.

[0043] On the first surface 10a of the substrate 10, wirings 11a, 11b, and 11c are formed at intervals so as not to contact each other. A catalyst layer 20a is formed covering a portion of wiring 11a, a catalyst layer 20b is formed covering a portion of wiring 11b, and a catalyst layer 20c serving as a reference electrode is formed covering a portion of wiring 11c. The wirings 11a, 11b, and 11c function as signal extraction wiring that electrically connects each catalyst layer to an external device. Portions of the wirings 11a, 11b, and 11c are exposed to the outside of the first cover 41 in a plan view of the substrate 10, and a connection portion 15 for connecting to an external circuit is formed in the exposed portion.

[0044] The conductor layer constituting the wiring 11 is formed on the first surface 10a of the substrate 10, for example, by forming copper foil over the entire surface of the insulating substrate, pattern-etching the copper foil, and further plating the remaining copper foil. An example of the wiring 11 is a layer in which the surface of copper is plated with nickel / gold, and has a thickness of 5 μm to 30 μm. Note that the wiring 11 may also be formed by other methods such as vapor deposition or printing. In FIGS. 3 and 4, for clarity of illustration, the wiring 11 is illustrated as being present within the substrate 10, but in this embodiment, the wiring 11 is formed on the first surface 10a of the substrate 10.

[0045] The connecting portion 15 is formed at the tip of the protruding portion 14 and has a through-hole that is circular in plan view and penetrates the protruding portion 14 in the thickness direction. When the through-hole has a perfect circular shape in plan view, its diameter is, for example, approximately the same as the diameter of the pin 113, and the pin 113 may be press-fitted into the connecting portion 15. The connecting portion 15 constitutes part of the wiring 11 connected to the gas detection unit 2, and the above-mentioned conductor layer is formed on the opening periphery and inner surface of the through-hole of the connecting portion 15. When the conductor layer of the connecting portion 15 abuts against the pin 113, the gas detection unit 2 and the pin 113 are electrically connected, and a signal from the gas detection unit 2 can be output to the outside. Note that when the connecting portion 15 has a semicircular shape in plan view (see FIG. 1 ), it can be said that a recess that abuts against the outer circumferential surface of the pin 113 is formed at the tip of the protruding portion 14.

[0046] [Catalyst layer] As described above, the catalyst layer 20 is formed directly on the first surface 10a of the substrate 10, which has the wiring 11 and the gas inlet hole 12. The catalyst layer 20 is preferably a coating formed by applying a catalyst material to the first surface 10a. The catalyst layer 20 is formed on the wiring 11, and a portion of the catalyst layer 20 may be formed in an area of ​​the first surface 10a where the wiring 11 is not present. When the catalyst layer 20 is applied to the first surface 10a, the catalyst layer 20 adheres strongly to the first surface 10a. In this embodiment, the electrolyte layer 30 is also applied to the catalyst layer 20, so the laminated structure of the gas detection unit 2 has strong adhesion. This reduces the resistance of the gas detection unit 2 without applying strong pressure to the laminated structure, and the resistance value is stabilized. As a result, the reliability of the sensor is improved, and the sensor can be made more sensitive, smaller, and less expensive.

[0047] The thickness of the catalyst layer 20 is, for example, 1 μm to 500 μm, or 10 μm to 200 μm. The catalyst layers 20a, 20b, and 20c constituting the catalyst layer 20 preferably have the same thickness. The catalyst layers 20a, 20b, and 20c are formed apart from each other on the first surface 10a so as not to overlap with each other. Each catalyst layer has, for example, a rectangular shape in plan view, but the shape of each catalyst layer in plan view is not particularly limited.

[0048] The catalyst constituting the catalyst layer 20 promotes the oxidation reaction of CO. The reaction of the above formula (1) occurs in the catalyst layer 20a, which is the working electrode. In this embodiment, each catalyst layer is made of the same material. Examples of catalysts include platinum (Pt), palladium (Pd), gold (Au), silver (Ag), ruthenium (Ru), rhodium (Rh), iridium (Ir), cobalt (Co), iron (Fe), and nickel (Ni). Among these, it is preferable to use a noble metal catalyst such as Pt or a PtRu alloy.

[0049] The catalyst layer 20 further includes a conductive support and an ionomer. The conductive support is a conductive material that holds the catalyst. Suitable examples of the conductive support include carbon black such as acetylene black and ketjen black, graphite carbon, and carbon materials such as carbon nanotubes. The catalyst is, for example, adhered to the particle surface of the carbon material. The ionomer is an ionically conductive material that allows the movement of protons generated by the reaction. Suitable examples of the ionically conductive material include Nafion (registered trademark: manufactured by DuPont), which has the same composition as the electrolyte membrane.

[0050] [Electrolyte layer] The electrolyte layer 30 is an ion-conducting membrane that transfers ions generated in the catalyst layer 20a to the catalyst layer 20b, and is an electrically insulating membrane that does not have electron conductivity. The electrolyte layer 30 may be formed, for example, by absorbing a liquid electrolyte into a support member such as a porous sheet, but is preferably a solid electrolyte membrane made of a polymer material. In this embodiment, a proton-conducting solid electrolyte membrane is used. An example of a proton-conducting solid electrolyte membrane is a polymer membrane in which proton-conducting groups such as sulfonic acid groups are introduced into a hydrocarbon-based polymer or a fluorine-based polymer. A commercially available product such as Nafion (registered trademark: manufactured by DuPont) may be used for the electrolyte layer 30.

[0051] The thickness of the electrolyte layer 30 is not particularly limited, but is, for example, 5 μm to 500 μm. The electrolyte layer 30 is preferably disposed so as to cover the entire catalyst layer 20, and a portion of it is formed directly on the first surface 10a of the substrate 10. The electrolyte layer 30 is, for example, a coating film formed by applying its constituent materials onto the first surface 10a on which the wiring 11 and catalyst layer 20 are formed. The electrolyte layer 30 has, for example, a rectangular shape in a plan view, but the shape of the electrolyte layer 30 in a plan view is not particularly limited and can be changed as appropriate depending on the shape of the electrochemical gas sensor 1, etc.

[0052] [cover] As described above, the cover 40 includes the first cover 41 and the second cover 42 and has a rectangular parallelepiped shape as a whole. The first cover 41 prevents gases, including CO and water vapor, from entering the sensor interior and protects the gas detection unit 2 from damage. The first cover 41 is made of a material with low gas permeability that can block gases such as CO and water vapor. While the first cover 41 may be made of a metal material, it is preferably made of a resin material from the standpoints of weight reduction, productivity, etc. Unlike the second cover 42, the first cover 41 does not have a gas inlet hole.

[0053] The first cover 41 may be a flexible thin-film sealing sheet, but is preferably made of a hard resin material. The first cover 41 is, for example, a hard cover formed in the shape of a bottomed rectangular tube, and is placed on the first surface 10a of the substrate 10 so as to cover the gas detection unit 2 from above. A gap (internal space) is formed between the first cover 41 and the gas detection unit 2 in the thickness direction of the substrate 10, and this internal space serves as an accommodation space for the humidity control member 60. In this embodiment, the first cover 41 is larger than the base portion 13 of the substrate 10, and the first cover 41 covers the entire first surface 10a of the base portion 13.

[0054] The second cover 42 covers the second surface 10b of the substrate 10, including the portion where the gas introduction holes 12 are formed. The second cover 42 preferably covers all of the gas introduction holes 12, forming an internal space between the second cover 42 and the second surface 10b. The second cover 42 has a second gas introduction hole 43 for introducing CO to the first gas introduction hole 12 of the substrate 10. CO that flows into the internal space from the gas introduction hole 43 acts on the gas detection unit 2 through the gas introduction hole 12. The gas introduction hole 43 is formed on the surface of the second cover 42 facing the second surface 10b. The shape of the gas introduction hole 43 in a plan view is not particularly limited and may be, for example, a circular shape, a polygonal shape, or a slit shape.

[0055] The second cover 42 may be a flexible thin-film sealing sheet like the first cover 41, but is preferably made of a hard resin material. The second cover 42 is made of a material with low gas permeability that can block gases such as CO and water vapor, and may be made of a metal material, but is preferably made of a resin material. The second cover 42 is, for example, a hard cover formed in the shape of a bottomed rectangular tube, and is disposed on the second surface 10b so as to cover the gas inlet hole 12 of the substrate 10.

[0056] The first cover 41 and the second cover 42 are formed in the shape of a flat, bottomed rectangular tube, but the shape of each cover is not particularly limited. However, from the perspective of miniaturizing the sensor, it is preferable to reduce the height of each cover from the surface of the substrate 10. As described above, the first cover 41 and the second cover 42 are fixed to each other with their open ends overlapping each other using, for example, adhesives, screws, a locking structure, or welding. The first cover 41 and the second cover 42 sandwich each of the protrusions 14 of the substrate 10 and also sandwich both ends of the base portion 13 along the long sides via the sealing member 50. The sealing member 50 may be provided between the substrate 10 and each of the protrusions 14.

[0057] In this embodiment, the opening area of ​​each gas inlet hole 12 in the substrate 10 is preferably smaller than the opening area of ​​each gas inlet hole 43 in the second cover 42. When the gas inlet holes 12 and 43 have a perfect circular shape, the diameter of the gas inlet hole 12 is preferably smaller than the diameter of the gas inlet hole 43. The opening area of ​​the gas inlet hole 12 needs to be small from the viewpoint of preventing the infiltration of the ink that forms the catalyst layer 20, but it is preferable that the opening area of ​​the gas inlet hole 43 be larger than that of the gas inlet hole 12 to ensure good ventilation. For example, when the gas inlet hole 43 is a circular hole, it has a diameter of 0.2 to 2.0 mm or 0.3 to 1.0 mm.

[0058] [Humidity control materials] The humidity control member 60 has the function of adjusting the amount of moisture contained in the solid electrolyte membrane, absorbing moisture when the humidity inside the sensor is high and releasing moisture when the humidity is low. The humidity control member 60 prevents, for example, an excessive decrease in humidity inside the sensor covered by the cover 40. The humidity control member 60 is preferably disposed in the internal space between the electrolyte layer 30 and the first cover 41 without contacting the first cover 41. The humidity control member 60 may expand when it absorbs moisture, but the gap between the first cover 41 and the humidity control member 60 can absorb the expansion of the humidity control member 60. The gap between the first cover 41 and the humidity control member 60 is preferably large enough so that the first cover 41 and the humidity control member 60 do not come into contact with each other even when the humidity control member 60 expands.

[0059] The humidity control member 60 is, for example, in the form of particles, and is disposed opposite the electrolyte layer 30 with the partition layer 70 interposed therebetween. The shape and size of the humidity control member 60 are not particularly limited. For example, the humidity control member 60 has a volume larger than that of the electrolyte layer 30. In this case, the humidity control member 60 has a sufficient amount of moisture relative to the electrolyte layer, making it possible to adjust the amount of moisture inside the sensor, leading to improved reliability and higher sensitivity of the sensor.

[0060] The humidity control member 60 is, for example, a sheet-like member containing humidity control particles that reversibly absorb and release water vapor. The humidity control member 60 may have a structure in which a plurality of humidity control particles are sandwiched between two base sheets. In this case, the humidity control particles and the humidity control particles and the two base sheets are bound together by a binder. There are no particular limitations on the type of binder, as long as it can maintain the sheet shape of the humidity control member 60. The base sheet may be a general thermoplastic resin sheet, but a porous sheet with breathability is preferable. Nonwoven fabric, woven fabric, etc. may also be used as the base sheet.

[0061] The humidity-conditioning particles may be particles containing a silicon compound such as silica, sepiolite, or zeolite, or may contain alumina, titania, zirconia, or the like instead of or together with the silicon compound. The humidity-conditioning particles may also be particles containing a highly water-absorbent polymer such as cross-linked sodium polyacrylate. As will be described in detail later, the particle size of the humidity-conditioning particles is preferably larger than the diameter of the vent holes in the partition wall layer 70. The average particle size of the humidity-conditioning particles is, for example, 30 μm to 10 mm or 500 μm to 5 mm. The average particle size of the humidity-conditioning particles is calculated by observing the particles with an optical microscope or a scanning electron microscope and averaging the diameters of the circumscribed circles of the particle images. When the humidity-conditioning particles absorb water and expand, the average particle size in the smallest state is preferably within this range.

[0062] [Partition layer] The partition wall layer 70 is a sheet-like member that is disposed between the electrolyte layer 30 and the humidity control member 60 in order to prevent contact between the electrolyte layer 30 and the humidity control member 60. If the humidity control member 60 is in contact with the electrolyte layer 30, excess moisture is expected to be supplied to the contact area, and therefore, it is preferable to interpose the partition wall layer 70 between the electrolyte layer 30 and the humidity control member 60. The shape and size of the partition wall layer 70 are not particularly limited, but it is preferable that the partition wall layer 70 has the same shape and size as the electrolyte layer 30 and is disposed so as to cover the entire electrolyte layer 30. The thickness of the partition wall layer 70 is not particularly limited, but is, for example, 30 μm to 1000 μm.

[0063] The partition layer 70 is preferably a breathable sheet. By covering the entire electrolyte layer 30 with the water vapor-permeable partition layer 70, the moisture content of the entire electrolyte layer can be adjusted while preventing contact between the electrolyte layer 30 and the humidity control member 60, leading to improved reliability and sensitivity of the sensor. A porous sheet having ventilation holes can be used for the partition layer 70, and nonwoven fabric, woven fabric, etc. may also be used. When the humidity control member 60 includes a porous substrate sheet, the sheet may function as the partition layer 70.

[0064] The diameter of the air vent holes in the partition wall layer 70 is, for example, less than 50 μm, which is smaller than the particle size of the humidity-conditioning particles in the humidity control member 60. The average particle size of the humidity-conditioning particles needs to be larger than the average diameter of the air vent holes, but the particle size of all the humidity-conditioning particles may be larger than the maximum diameter of the air vent holes. In this case, even if the humidity-conditioning particles are present directly on the partition wall layer 70, the humidity-conditioning particles are prevented from penetrating the air vent holes, ensuring the breathability of the partition wall layer 70 and preventing contact between the electrolyte layer 30 and the humidity-conditioning particles. The average diameter of the air vent holes is, for example, 0.1 μm to 30 μm or 0.5 μm to 25 μm. The average diameter of the air vent holes is measured using a mercury porosimeter.

[0065] Alternatively, the partition layer 70 may be made of a sheet-shaped resin material, which has high strength and therefore improves assembly during manufacturing. In this case, the resin material has through-holes for ventilation, which can adjust the moisture content of the entire electrolyte layer while preventing contact between the electrolyte layer 30 and the humidity control member 60, leading to improved reliability and sensitivity of the sensor. The through-holes formed in the sheet-shaped resin material may have, for example, a perfect circular shape in a plan view and a diameter of less than 1000 μm. In this case, by selecting humidity-controlling particles that are larger than the diameter of the through-holes, the humidity-controlling particles are prevented from penetrating the through-holes, ensuring the breathability of the partition layer 70 and preventing contact between the electrolyte layer 30 and the humidity-controlling particles. The average diameter of the through-holes is, for example, 100 μm to 500 μm, and the average diameter of the through-holes is measured using an optical microscope or the like.

[0066] [Activated carbon] As described above, the activated carbon 80 is disposed between the substrate 10 and the second cover 42. An oxidation reaction of carbon monoxide occurs at the working electrode. By measuring the short-circuit current generated during this reaction, the activated carbon 80 adsorbs gases such as SOx and NOx and allows CO, the target gas, to pass through. The activated carbon 80 may be granular or powdered activated carbon formed into a block shape, granular or powdered activated carbon filled in a case with ventilation holes, or activated carbon formed into a cloth shape (activated carbon cloth). From the perspective of miniaturizing the sensor, the activated carbon 80 is preferably processed into a sheet shape as a whole, and is disposed so as to cover all of the gas inlet holes 12 formed in the substrate 10. Between the second surface 10b of the substrate 10 and the second cover 42, for example, a humidity control member 60 and activated carbon 80 may be layered in this order from the second surface 10b side.

[0067] An example of a method for manufacturing the electrochemical gas sensor 1 having the above-described configuration will be described below. The electrochemical gas sensor 1 is manufactured, for example, through the following steps. (1) A step of forming wiring 11 on first surface 10a of substrate 10 having gas introduction holes 12 that connect first surface 10a and second surface 10b. (2) A step of forming a catalyst layer 20 on the first surface 10a of the substrate 10 so as to cover a part of the wiring 11 and the gas introduction hole 12. (3) A step of forming an electrolyte layer 30 on the first surface 10a of the substrate 10 so as to cover the catalyst layer 20. (4) A step of disposing a cover 40 so as to cover the catalyst layer 20 and the electrolyte layer 30 and to expose a portion of the wiring 11 on the first surface 10a of the substrate 10.

[0068] In step (1), a metal layer such as copper foil is formed on the first surface 10a of the substrate 10, and the wiring 11 including wirings 11a, 11b, and 11c is formed by pattern etching of the copper foil. Alternatively, the wirings 11a, 11b, and 11c may be directly formed by vapor deposition, printing, or the like. The wiring 11 may also have a plating layer of nickel / gold or the like. In this embodiment, there are no through holes other than the gas introduction hole 12 in the area of ​​the substrate 10 covered by the cover 40, and the amount of CO acting on the gas detection unit is controlled.

[0069] In step (2), for example, an ink containing a catalyst, a conductive carrier, and an ionomer is applied to the first surface 10a of the substrate 10 on which the wiring 11 is formed, and the coating is dried to volatilize and remove the dispersion medium, thereby forming the catalyst layer 20. Each catalyst layer is formed to the same thickness using the same type of ink. In this embodiment, the catalyst layer 20a is formed by applying ink to the first surface 10a so as to cover all of the gas inlet holes 12. The opening area of ​​the gas inlet holes 12, the viscosity of the ink, and the like are adjusted so that the ink forming the catalyst layer 20a does not penetrate into the gas inlet holes 12.

[0070] Examples of ink application methods include spray coating, screen printing, inkjet printing, electrolytic spray coating, and dispensing.

[0071] In step (3), for example, ink containing a constituent material of the solid electrolyte is applied to the first surface 10a of the substrate 10 so as to cover the entire catalyst layer 20, and the coating is dried to volatilize and remove the dispersion medium, thereby forming the electrolyte layer 30. The method for applying the ink is not particularly limited, and a method similar to that in step (2) can be applied. Forming the electrolyte layer 30 by a coating method strengthens the adhesion of the electrolyte layer 30 to the catalyst layer 20 and the first surface 10a, thereby reducing the contact resistance of the laminated structure of the gas detection unit.

[0072] In step (4), a first cover 41 is placed so as to entirely cover the gas detection unit 2 formed on the first surface 10a, and a second cover 42 is placed so as to cover the portion of the substrate 10 where the gas introduction hole 12 is formed from the second surface 10b side. The first cover 41 and the second cover 42 entirely cover the substrate 10, including the side surfaces of the base portion 13, and are connected to each other while sandwiching three protrusions 14 from both sides in the thickness direction. A sealing member 50 may be provided between the cover 40 and the substrate 10. Each protrusion 14 protrudes outside the cover 40 from between the first cover 41 and the second cover 42, and is connected to an external terminal such as a pin 113 by a connection portion 15 formed on the protrusion 14.

[0073] The cover 40 does not function as a member that presses the gas detection unit 2, and an internal space exists between the gas detection unit 2 and the first cover 41. It is preferable to dispose a humidity control member 60 and a partition layer 70 in this internal space, and the humidity control member 60 is disposed on the gas detection unit via the partition layer 70. It is also possible to form the humidity control layer by applying ink containing the constituent material of the partition layer 70 onto the electrolyte layer 30 to form the partition layer 70, and then applying ink containing humidity control particles onto the partition layer 70.

[0074] FIG. 5 is a diagram showing a modified example of the electrochemical gas sensor 1. The embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 4 and other figures in that a leaf spring 90 is provided to sandwich the first cover 41 and the second cover 42 from the outside and maintain the first cover 41 and the second cover 42 in an integrated state. The first cover 41 and the second cover 42 sandwich the substrate 10, and the leaf spring 90 presses each cover in the thickness direction of the substrate 10. The leaf spring 90 is attached, for example, from both sides of the short side of the cover, which is a direction perpendicular to the direction in which the protrusion 14 extends. The first cover 41 and the second cover 42 may be integrated only by the biasing force of the leaf spring 90, or they may be fixed to each other by adhesive, screws, an engagement structure, welding, etc., and integrated by the biasing force of the leaf spring 90.

[0075] The embodiment shown in FIG. 5 differs from the embodiment shown in FIG. 4 and the like in that the side surface of the substrate 10 along the thickness direction is exposed from the cover. The side surface of the substrate 10 (base portion 13) is exposed to the outside between the first cover 41 and the second cover 42 and is, for example, disposed flush with the side surface of the cover. A sealing member 51 is disposed between the first cover 41 and the second cover 42 and the substrate 10, and each cover presses the substrate 10 from both sides in the thickness direction via the sealing member 51 by the biasing force of the leaf spring 90. This seals the connecting portion between the first cover 41 and the second cover 42, and the target gas is introduced only through the gas inlet hole 43 of the second cover 42. The sealing member 51 is preferably disposed in a ring shape so as to surround the outer edge of the substrate 10.

[0076] 6 is a diagram showing another modified example of the electrochemical gas sensor 1. The embodiment shown in FIG. 6 is similar to the embodiment shown in FIG. 5 in that the side surface of the substrate 10 (base portion 13) is exposed to the outside from between the first cover 41 and the second cover 42. As in the above embodiment, the substrate 10 has a protruding portion 95 that protrudes from between the first cover 41 and the second cover 42, but differs from the above embodiment in that there is only one protruding portion 95. The protruding portion 95 extends from one end of the cover in the width direction and is formed with a constant width over the entire length of the cover.

[0077] On one surface of the protrusion 95, a working electrode wire 11a, a counter electrode wire 11b, and a reference electrode wire 11c are formed, each extending from the interior of the sensor covered by the first cover 41. Furthermore, connection portions 15a, 15b, and 15c are formed at the tip of each wire. That is, in the embodiment shown in FIG. 6, multiple connection portions are formed on one protrusion 95. Each connection portion has, for example, a through-hole that is circular in plan view and penetrates the protrusion 95 in the thickness direction, and a conductor layer formed on the periphery and inner surface of the through-hole. The connection portions 15a, 15b, and 15c are formed in a row along the length of the protrusion 95.

[0078] Fig. 7 is a block diagram showing the configuration of a gas detection system 100 according to an embodiment. As shown in Fig. 7, the gas detection system 100 includes a gas detection device 110 including an electrochemical gas sensor 1, a receiving device 101 that receives detection information from the gas detection device 110, and a control device 102. The receiving device 101 and the control device 102 may be installed in a location remote from the gas detection device 110, and the receiving device 101 may receive the detection information from the gas detection device 110 via wireless or wired communication, or via a wide area communication network such as the Internet. The control device 102 controls the operation of a predetermined device, for example, based on the detection information from the gas detection device 110.

[0079] Gas detection device 110 includes electrochemical sensor 1 and housing 111 that houses electrochemical gas sensor 1. Gas detection device 110 also includes circuit board 112. As shown in FIG. 1 , electrochemical gas sensor 1 may be housed in recess 114 of circuit board 112, and mounted on circuit board 112 by inserting pins 113 of circuit board 112 into connecting portions 15 formed on protruding portion 14 of substrate 10. Gas detection device 110 may also include a holder for holding electrochemical sensor 1, a speaker that outputs an alarm, a warning lamp, etc. Gas detection device 110 may also include a detector for detecting at least one of smoke and heat, and in this case may also include a speaker that outputs an alarm, a warning lamp, etc.

[0080] As described above, the electrochemical sensor 1 having the above configuration has a simple signal extraction structure, which, for example, allows for the sensor to be made smaller and less expensive. This makes it easy to connect to an external device such as the gas detection device 110. Furthermore, the electrochemical sensor 1 is, for example, highly reliable, can be manufactured at low cost, and has high sensitivity. By providing the humidity control member 60, the partition layer 70, and the activated carbon 80, further improvements in reliability and sensitivity can be achieved.

[0081] The above-described embodiments may be modified as appropriate without departing from the scope of the present disclosure. For example, in the above-described embodiments, the reference electrode catalyst layer is formed using the same electrode material as the working electrode catalyst layer 20a and the counter electrode catalyst layer 20b. However, the reference electrode may be made of a different material from the catalyst layers 20a and 20b, and the catalyst layers 20a and 20b may be made of different materials. The electrochemical gas sensor may have a two-electrode structure including only a working electrode and a counter electrode. Alternatively, a metal layer may be used as the reference electrode, and the counter electrode may also serve as the reference electrode. The electrochemical gas sensor may also include other components, such as a gas diffusion layer.

[0082] Although the electrochemical sensor 1 includes a humidity control member 60, a partition layer 70, and activated carbon 80, the electrochemical sensor according to the present disclosure is not limited to having a humidity control member 60, a partition layer 70, and activated carbon 80. The electrochemical sensor according to the present disclosure may include, for example, only the humidity control member 60 or the activated carbon 80, or may have a structure in which the activated carbon 80 is disposed between the gas detection unit 2 and the first cover 41. The humidity control member 60 may also be disposed between the substrate 10 and the second cover 42.

[0083] The electrochemical gas sensor according to the present disclosure only includes a cover that covers the first surface 10a of the substrate 10, and this cover is in close contact with the first surface 10a of the substrate 10 around the gas detection unit 2, for example. In this case, a sealing member may be disposed between the cover and the first surface 10a of the substrate 10, and a leaf spring may be provided to sandwich the cover and the substrate 10 from the outside and maintain the cover and the substrate 10 in an integrated state.

[0084] The present disclosure is further illustrated by the following embodiments. Configuration 1: An electrochemical gas sensor comprising: a substrate including a first surface and a second surface; a gas detection unit arranged on the first surface of the substrate; a cover covering the gas detection unit; and wiring connected to the gas detection unit, a portion of which is exposed from the cover, wherein the portion of the wiring exposed from the cover has a connection portion formed thereon to be connected to an external wiring or an external terminal. Configuration 2: The electrochemical gas sensor according to configuration 1, wherein the substrate has a protruding portion protruding from the cover, and the connection portion is formed on the protruding portion. Configuration 3: The electrochemical gas sensor according to configuration 2, wherein a plurality of the connection portions are formed on the protruding portion. Configuration 4: The electrochemical gas sensor according to configuration 2, wherein the electrochemical gas sensor has a plurality of the protrusions, and the connection portion is formed on each of the protrusions. Configuration 5: An electrochemical gas sensor according to any one of configurations 2 to 4, wherein the cover is composed of a first cover covering the first surface of the substrate and a second cover covering the second surface of the substrate, and the protruding portion of the substrate is sandwiched between the first cover and the second cover. Configuration 6: The electrochemical gas sensor according to Configuration 5, wherein the cover covers the entire substrate except for the protruding portion. Configuration 7: The electrochemical gas sensor according to Configuration 5 or 6, wherein the first cover and the second cover accommodate the portion of the substrate other than the protruding portion and are connected to each other. Configuration 8: An electrochemical gas sensor according to any one of configurations 5 to 7, wherein the substrate has a first gas inlet hole that connects the first surface and the second surface in the area overlapping with the gas detection unit, and the second cover has a second gas inlet hole and covers the second surface of the substrate including the portion where the first gas inlet hole is formed. Configuration 9: The electrochemical gas sensor according to configuration 8, wherein the opening area of ​​the first gas introduction hole of the substrate is smaller than the opening area of ​​the second gas introduction hole of the second cover. Configuration 10: The electrochemical gas sensor according to any one of configurations 1 to 9, wherein the connection portion includes a through-hole that is circular or semicircular in plan view. Configuration 11: The electrochemical gas sensor according to any one of configurations 1 to 10, further comprising a sealing member disposed between the cover and the first surface of the substrate, and a leaf spring that sandwiches the cover and the substrate from the outside and maintains the cover and the substrate in an integrated state. Configuration 12: An electrochemical gas sensor according to any one of configurations 5 to 9, further comprising a sealing member arranged between at least one of the first cover and the second cover and the substrate, and a leaf spring that sandwiches the first cover and the second cover from the outside and maintains the first cover and the second cover in an integrated state. Configuration 13: The electrochemical gas sensor according to any one of configurations 5 to 9 and 12, further comprising a humidity control member housed within the first cover without contacting the gas detection unit. Configuration 14: The electrochemical gas sensor according to configuration 13, further comprising an air-permeable partition layer disposed between the gas detection unit and the humidity control member. Configuration 15: The electrochemical gas sensor according to any one of Configurations 5 to 9, 12, and 14, further comprising activated carbon disposed within the second cover. [Explanation of symbols]

[0085] 1 electrochemical gas sensor, 10 substrate, 10a first surface, 10b second surface, 11, 11a, 11b, 11c wiring, 12, 43 gas inlet hole, 13 base portion, 14, 14a, 14b, 14c protrusion portion, 15, 15a, 15b, 15c connection portion, 20, 20a, 20b, 20c catalyst layer, 30 electrolyte layer, 40 cover, 41 first cover, 42 second cover, 50, 51 sealing member, 60 humidity control member, 70 partition layer, 80 activated carbon, 90 leaf spring, 100 gas detection system, 101 receiving device, 102 control device, 110 gas detection device, 111 housing, 112 circuit board, 113 pin

Claims

1. a substrate including a first side and a second side; a gas detection unit disposed on the first surface of the substrate; a cover for covering the gas detection unit; a wiring connected to the gas detection unit and partly exposed from the cover; Equipped with The electrochemical gas sensor has a connection portion formed on the portion of the wiring exposed from the cover, the connection portion being connected to an external wiring or an external terminal.

2. the substrate has a protrusion protruding from the cover, 2. The electrochemical gas sensor according to claim 1, wherein the connection portion is formed on the protrusion.

3. 3. The electrochemical gas sensor according to claim 2, wherein a plurality of said connection portions are formed on said protruding portion.

4. a plurality of the protrusions; 3. The electrochemical gas sensor according to claim 2, wherein the connection portion is formed on each of the protrusions.

5. the cover includes a first cover that covers the first surface of the substrate and a second cover that covers the second surface of the substrate; 3. The electrochemical gas sensor according to claim 2, wherein the protruding portion of the substrate is sandwiched between the first cover and the second cover.

6. 6. The electrochemical gas sensor according to claim 5, wherein the cover covers the entire substrate except for the protrusion.

7. 6. The electrochemical gas sensor according to claim 5, wherein the first cover and the second cover accommodate a portion of the substrate other than the protruding portion and are connected to each other.

8. the substrate has a first gas introduction hole that connects the first surface and the second surface in a region overlapping with the gas detection unit, 6. The electrochemical gas sensor according to claim 5, wherein the second cover has a second gas inlet hole and covers the second surface of the substrate including a portion where the first gas inlet hole is formed.

9. 9. The electrochemical gas sensor according to claim 8, wherein an opening area of ​​the first gas inlet hole of the substrate is smaller than an opening area of ​​the second gas inlet hole of the second cover.

10. 2. The electrochemical gas sensor according to claim 1, wherein the connection portion includes a through-hole that is circular or semicircular in plan view.

11. a sealing member disposed between the cover and the first surface of the substrate; a leaf spring that sandwiches the cover and the substrate from the outside and maintains the cover and the substrate in an integrated state; The electrochemical gas sensor according to claim 1 , further comprising:

12. a sealing member disposed between at least one of the first cover and the second cover and the substrate; a leaf spring that sandwiches the first cover and the second cover from the outside and maintains the first cover and the second cover in an integrated state; The electrochemical gas sensor according to claim 5 , further comprising:

13. 6. The electrochemical gas sensor according to claim 5, further comprising a humidity control member housed within said first cover without contacting said gas detection unit.

14. 14. The electrochemical gas sensor according to claim 13, further comprising an air-permeable partition layer disposed between the gas detection unit and the humidity control member.

15. 6. The electrochemical gas sensor according to claim 5, further comprising activated carbon disposed within the second cover.

16. A gas detection device comprising: the electrochemical gas sensor according to any one of claims 1 to 15; and a housing that houses the electrochemical gas sensor.

17. 17. A gas detection system comprising: the gas detection device according to claim 16; and a receiving device that receives detection information from the gas detection device.

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