Oxygen sensor, manufacturing method thereof, engine and vehicle

Abstract

The invention discloses an oxygen sensor and a manufacturing method thereof, an engine and a vehicle. The oxygen sensor comprises a first electrolyte layer, an electrolyte covering layer and a second electrolyte layer which are sequentially stacked, wherein a first diffusion channel is arranged in the first electrolyte layer; at least one second diffusion channel is arranged in the electrolyte covering layer; the total area of the cross sections of all the second diffusion channels is smaller than the area of the cross section of the first diffusion channel; a diffusion barrier and a detection cavity are arranged in the second electrolyte layer, the diffusion barrier is communicated with the first diffusion channel at least through the second diffusion channel, and the detection cavity is communicated with the second diffusion channel at least through the diffusion barrier.

Description

Technical Field

[0001] The present application relates to the field of gas sensors, and more particularly to an oxygen sensor and its manufacturing method, an engine, and a vehicle. Background Art

[0002] An oxygen sensor can convert the oxygen concentration in a gas to be measured into an electrical signal readable by a computer, and plays a crucial role in the fields of automobiles, medical treatment, industry, and environmental monitoring. For example, an oxygen sensor can be applied to an engine to detect the oxygen concentration in the engine exhaust. In related technologies, during the lamination molding process of the oxygen sensor, the diffusion barrier is prone to cracking, resulting in a low product yield. Summary of the Invention

[0003] The present application is proposed to solve at least one of the above problems. According to a first aspect of the present application, there is provided an oxygen sensor, which includes: a first electrolyte layer, an electrolyte covering layer, and a second electrolyte layer laminated in sequence; wherein, a first diffusion channel is provided in the first electrolyte layer; at least one second diffusion channel is provided in the electrolyte covering layer; and the total cross-sectional area of all the second diffusion channels is smaller than the cross-sectional area of the first diffusion channel; a diffusion barrier and a detection cavity are provided in the second electrolyte layer, the diffusion barrier is communicated with the first diffusion channel at least through the second diffusion channel, and the detection cavity is communicated with the second diffusion channel at least through the diffusion barrier.

[0004] In an embodiment of the present application, each of the second diffusion channels is opposite to the first diffusion channel in position.

[0005] In an embodiment of the present application, a third diffusion channel is provided in the diffusion barrier, the third diffusion channel is communicated with the first diffusion channel through the second diffusion channel, and the third diffusion channel is communicated with the detection cavity through the diffusion barrier.

[0006] In an embodiment of the present application, the cross-sectional shape of the diffusion barrier is annular; wherein, the third diffusion channel is a diffusion through hole at the center of the diffusion barrier, and the detection cavity is located outside the diffusion barrier.

[0007] In an embodiment of the present application, the cross-sectional area of the third diffusion channel is larger than the total cross-sectional area of all the second diffusion channels, and each of the second diffusion channels is opposite to the third diffusion channel in position.

[0008] In an embodiment of the present application, the third diffusion channel has the same cross-sectional size as the first diffusion channel and is opposite to the first diffusion channel in cross-sectional position.

[0009] In one embodiment of the present application, accommodation through holes are provided in the second electrolyte layer, and the diffusion barrier and the detection cavity are disposed within the accommodation through holes.

[0010] In one embodiment of the present application, each of the second diffusion channels is opposite to the diffusion barrier in position, and the space in the accommodation through hole except for the diffusion barrier forms the detection cavity.

[0011] In one embodiment of the present application, the first diffusion channel is a diffusion through hole, and / or the second diffusion channel is a diffusion through hole.

[0012] In one embodiment of the present application, the second diffusion channel is a diffusion slit with a rectangular cross-section. The length of the diffusion slit is 100 μm to 300 μm, and the width of the diffusion slit is 5 μm to 50 μm.

[0013] In one embodiment of the present application, the thickness of the electrolyte covering layer is 50 μm to 200 μm.

[0014] In one embodiment of the present application, the material of the electrolyte covering layer is zirconia ceramic doped with yttrium oxide or scandium oxide; wherein, the molar mass of yttrium oxide or scandium oxide in the zirconia ceramic is 3% to 8%.

[0015] In one embodiment of the present application, a test electrode is provided on the surface of the first electrolyte layer facing away from the electrolyte covering layer, a common electrode is provided in the detection cavity, and the pump cell of the oxygen sensor includes the test electrode and the common electrode.

[0016] In one embodiment of the present application, the oxygen sensor further includes a reference cavity for accommodating a reference gas. A reference electrode is provided in the reference cavity, and the Nernst cell of the oxygen sensor includes the reference electrode and the common electrode.

[0017] In one embodiment of the present application, the reference cavity is provided in the second electrolyte layer, and the reference cavity and the detection cavity are separated by the second electrolyte layer.

[0018] In one embodiment of the present application, the reference cavity is a notch at the edge of the second electrolyte layer.

[0019] According to a second aspect of the present application, a manufacturing method of an oxygen sensor is further provided. The manufacturing method includes: forming a first diffusion channel in a first electrolyte layer; forming a diffusion barrier and a detection cavity in a second electrolyte layer; forming at least one second diffusion channel in an electrolyte covering layer; and the total cross-sectional area of all the second diffusion channels is smaller than the cross-sectional area of the first diffusion channel; laminating the first electrolyte layer, the electrolyte covering layer, and the second electrolyte layer in sequence; the diffusion barrier is at least communicated with the first diffusion channel through the second diffusion channel, and the detection cavity is at least communicated with the second diffusion channel through the diffusion barrier.

[0020] In an embodiment of the present application, before forming at least one second diffusion channel in the electrolyte covering layer, the manufacturing method further includes: sintering the first electrolyte layer, the electrolyte covering layer, and the second electrolyte layer laminated in sequence.

[0021] According to a third aspect of the present application, an engine is further provided. The engine includes: any one of the above-mentioned oxygen sensors.

[0022] According to a fourth aspect of the present application, a vehicle is further provided. The vehicle includes: any one of the above-mentioned oxygen sensors, or any one of the above-mentioned engines.

[0023] According to the oxygen sensor, its manufacturing method, the engine, and the vehicle provided by the embodiments of the present application, by adding an electrolyte covering layer between the first electrolyte layer and the second electrolyte layer, during the lamination and molding process of the oxygen sensor, the pressure distribution of the electrolyte covering layer on the diffusion barrier is relatively uniform, preventing the diffusion barrier from cracking and improving the product yield. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a cross-sectional schematic view of an oxygen sensor shown in an embodiment of the present invention;

[0026] Figure 2 It is a cross-sectional schematic view of an oxygen sensor shown in another embodiment of the present invention;

[0027] Figure 3 It is a cross-sectional schematic view of an oxygen sensor shown in another embodiment of the present invention.

[0028] Reference Signs:

[0029] 11 - First electrolyte layer 12 - Second electrolyte layer 13 - Third electrolyte layer

[0030] 14 - Fourth electrolyte layer 15 - Fifth electrolyte layer 20 - Electrolyte covering layer

[0031] 21 - Diffusion barrier 22 - Detection cavity 23 - Reference cavity 31 - First diffusion channel

[0032] 32 - Second diffusion channel 33 - Third diffusion channel 41 - First common electrode

[0033] 42 - Second common electrode 43 - Test electrode 44 - Reference electrode

[0034] 45 - Heating electrode 51 - Electrode protection layer 52 - Insulating layer Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present invention more obvious, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments of the present invention. It should be understood that the present invention is not limited by the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other instances, some well-known technical features are not described to avoid confusion with the present invention.

[0037] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0038] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. When used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, identify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. When used herein, the term "and / or" includes any and all combinations of the related listed items.

[0039] To thoroughly understand the present invention, detailed structures will be presented in the following description to illustrate the technical solutions proposed by the present invention. The optional embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementation manners.

[0040] In the related art, a relatively thin covering layer is provided on the upper surface of the diffusion barrier. The covering layer is thin and only covers the upper surface of the diffusion barrier, that is, a covering layer with the same size as the diffusion barrier is provided on the upper surface of the diffusion barrier for sealing and covering the diffusion barrier. However, this covering method results in a relatively small covering area of the diffusion barrier. During the subsequent lamination molding process of the oxygen sensor, the covering layer with a small area will cause a relatively high risk of rupture of the diffusion barrier, increasing the manufacturing difficulty; moreover, the manufactured product is extremely likely to cause the diffusion barrier to be poorly sealed or incompletely covered, bringing difficulties to the precise control of the pump current and resulting in a relatively low product yield. To solve the above technical problems, the following implementation manners are provided in this application.

[0041] The following will describe in detail some implementation manners of the present invention with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0042] First, the application scenario of the oxygen sensor exemplified in this application is introduced. This oxygen sensor is used to measure the oxygen concentration in the gas to be measured. This oxygen sensor can be a wide-range oxygen sensor.

[0043] Reference Figures 1 to 3 , an oxygen sensor is provided in an embodiment of this application. The oxygen sensor includes: a first electrolyte layer 11, an electrolyte covering layer 20, and a second electrolyte layer 12 that are stacked in sequence; wherein, a first diffusion channel 31 is provided in the first electrolyte layer 11; at least one second diffusion channel 32 is provided in the electrolyte covering layer 20; and the total cross-sectional area of all the second diffusion channels 32 is smaller than the cross-sectional area of the first diffusion channel 31; a diffusion barrier 21 and a detection cavity 22 are provided in the second electrolyte layer 12. The diffusion barrier 21 is at least communicated with the first diffusion channel 31 through the second diffusion channel 32, and the detection cavity 22 is at least communicated with the second diffusion channel 32 through the diffusion barrier 21.

[0044] In the above solution, by adding an electrolyte covering layer 20 between the first electrolyte layer 11 and the second electrolyte layer 12, during the lamination molding process of the oxygen sensor, the pressure distribution of the electrolyte covering layer 20 on the diffusion barrier 21 is relatively uniform, preventing the diffusion barrier 21 from rupturing and improving the product yield. The following will introduce the above various structures in detail with reference to the accompanying drawings.

[0045] When setting the first electrolyte layer 11, reference Figures 1 to 3, the material of the first electrolyte layer 11 may be a solid electrolyte layer. A first diffusion channel 31 is provided in the first electrolyte layer 11, that is, the first diffusion channel 31 penetrates through the two opposite upper and lower surfaces of the first electrolyte layer 11. The first diffusion channel 31 is used to introduce the gas to be measured, that is, the first diffusion channel 31 is in communication with the gas to be measured, so that the gas to be measured can enter the first diffusion channel 31. Exemplarily, the first diffusion channel 31 may only include diffusion through-holes such as Figures 1 to 3 in it. Of course, in other embodiments, the first diffusion channel 31 may further include a porous filler filled in the diffusion through-hole. That is, as long as the setting mode of the diffusion channel capable of diffusing the gas to be measured is within the protection scope of the first diffusion channel 31 in the embodiments of the present application.

[0046] When setting the second electrolyte layer 12, refer to Figures 1 to 3 , the material of the second electrolyte layer 12 may be a solid electrolyte layer. A diffusion barrier 21 and a detection cavity 22 are provided in the second electrolyte layer 12. The diffusion barrier 21 is at least in communication with the first diffusion channel 31 through a second diffusion channel 32, and the detection cavity 22 is at least in communication with the second diffusion channel 32 through the diffusion barrier 21, so that the gas to be measured enters the detection cavity 22 at least through the first diffusion channel 31, the second diffusion channel 32 and the diffusion barrier 21.

[0047] There are various ways to set the diffusion barrier 21 and the detection cavity 22 in the second electrolyte layer 12. Exemplarily, refer to Figures 1 to 3 , accommodation through-holes may be provided in the second electrolyte layer 12, that is, the accommodation through-holes penetrate through the two opposite upper and lower surfaces of the second electrolyte layer 12. The diffusion barrier 21 and the detection cavity 22 are provided in the accommodation through-hole, that is, the diffusion barrier 21 and the detection cavity 22 are provided in the accommodation through-hole. The diffusion barrier 21 separates the detection cavity 22 from the first diffusion channel 31, that is, the gas to be measured entering from the first diffusion channel 31 needs to pass through the diffusion barrier 21 at least before entering the detection cavity 22. The diffusion barrier 21 may be a layer structure with a certain porosity, so that the gas to be measured can pass through the diffusion barrier 21 and enter the detection cavity 22. Exemplarily, the diffusion barrier 21 may be porous zirconia or porous alumina, and the porosity of the diffusion barrier 21 may be 20% - 50%. Exemplarily, by controlling the porosity of the diffusion barrier 21, the diffusion rate of the gas to be measured passing through the diffusion barrier 21 and entering the detection cavity 22 can be adjusted, so as to control the magnitude of the pump current. Specifically, since the diffusion mode of the gas to be measured in the diffusion barrier 21 is physical diffusion, after the porosity of the diffusion barrier 21 is determined, the limiting rate of the gas to be measured diffusing into the detection cavity 22 is determined. Refer to Figures 1 to 3, the pump cell of the oxygen sensor includes a test electrode 43 and a common electrode, and the common electrode can be the first common electrode 41. When a voltage is applied across the pump cell (the test electrode 43 and the first common electrode 41), a current will be formed inside the pump cell due to the flow of oxygen ions, pumping oxygen out of or into the detection chamber 22. Since there is a limit value for the gas diffusion rate in the diffusion barrier 21, the flow rate of oxygen ions in the pump cell will not increase infinitely with the increase of the applied voltage, thus forming a limiting oxygen ion flow, that is, the pump current. Therefore, the magnitude of the pump current can be adjusted by adjusting the porosity of the diffusion barrier 21. Exemplarily, the upper end of the accommodation through-hole is in contact with the electrolyte covering layer 20, and the lower end of the accommodation through-hole can be in contact with other electrolyte layers.

[0048] When setting the electrolyte covering layer 20, refer to Figure 1 and Figure 2 , the electrolyte covering layer 20 is clamped between the first electrolyte layer 11 and the second electrolyte layer 12, and the first electrolyte layer 11, the electrolyte covering layer 20, and the second electrolyte layer 12 are stacked in sequence. The electrolyte covering layer 20 is used to seal and cover the diffusion barrier 21 to improve the sealing density of the diffusion barrier 21. At least one second diffusion channel 32 is provided in the electrolyte covering layer 20, and each second diffusion channel 32 penetrates through the two opposite upper and lower surfaces of the electrolyte covering layer 20. And the total cross-sectional area of all the second diffusion channels 32 is smaller than the cross-sectional area of the first diffusion channel 31. Whether the number of the second diffusion channels 32 is one, or two or more, the total area obtained by summing the cross-sectional areas of all the second diffusion channels 32 is still smaller than the cross-sectional area of the first diffusion channel 31, so as to ensure that the added electrolyte covering layer 20 has a better covering and sealing effect on the diffusion barrier 21 compared with the way that the first electrolyte layer 11 is directly stacked on the second electrolyte layer 12. And the first diffusion channel 31 can communicate with the second diffusion channel 32, that is, the gas to be measured entering from the first diffusion channel 31 can pass through the second diffusion channel 32 through the electrolyte covering layer 20 and enter the detection chamber 22 at least through the diffusion barrier 21. That is, the diffusion barrier 21 is at least communicated with the first diffusion channel 31 through the second diffusion channel 32, and the detection chamber 22 is at least communicated with the second diffusion channel 32 through the diffusion barrier 21, so that the gas to be measured enters the detection chamber 22 at least through the first diffusion channel 31, the second diffusion channel 32, and the diffusion barrier 21.

[0049] Compared with the related art, in the embodiment of the present application, an electrolyte covering layer 20 is additionally provided between the first electrolyte layer 11 and the second electrolyte layer 12. The pore edge of the first diffusion channel 31 presses against the electrolyte covering layer 20, and the area of the electrolyte covering layer 20 is much larger than the area of the diffusion barrier 21. During the stacking and molding process of the oxygen sensor, the electrolyte covering layer 20 can evenly disperse the concentrated stress at the pore edge position of the first diffusion channel 31 to the diffusion barrier 21 and the second electrolyte layer 12, making the pressure distribution on the diffusion barrier 21 relatively uniform, preventing the diffusion barrier 21 from cracking, and improving the product yield. It can be seen that the embodiment of the present application replaces the covering layer with a relatively small covering area on the upper surface of the diffusion barrier 21 in the related art, and solves the problems that the covering layer on the upper part of the diffusion barrier 21 is not tightly sealed or incompletely covered, resulting in the cracking or air leakage of the covering layer or the diffusion barrier 21 during the subsequent molding process, which brings difficulties to the regulation of the pump current. Moreover, the oxygen sensor shown in the embodiment of the present application has a simpler structure, is easier to manufacture, has a better sealing effect, improves the regulation accuracy of the pump current, reduces the manufacturing difficulty of the oxygen sensor, and also improves the manufacturing yield and control accuracy of the oxygen sensor.

[0050] Exemplarily, each second diffusion channel 32 can be positioned opposite to the first diffusion channel 31, so that each second diffusion channel 32 can communicate with the first diffusion channel 31 to diffuse the gas to be measured in the first diffusion channel 31 into the second diffusion channel 32. Exemplarily, the cross-sectional dimension of each second diffusion channel 32 can be smaller than the cross-sectional dimension of the first diffusion channel 31, and each second diffusion channel 32 is positioned opposite to the first diffusion channel 31, so as to ensure that the total cross-sectional area of all the second diffusion channels 32 is smaller than the cross-sectional area of the first diffusion channel 31.

[0051] Exemplarily, the electrolyte covering layer 20 can be a thin solid electrolyte layer, and the length and width of the electrolyte covering layer 20 can be equal to the length and width of other electrolyte layers.

[0052] Regarding the number of the second diffusion channels 32, it can be one or multiple. Exemplarily, when the number of the second diffusion channels 32 is multiple, the multiple second diffusion channels 32 can be arranged in ways such as but not limited to array arrangement, single-row arrangement, random distribution, etc. Exemplarily, refer to Figures 1 to 3, the second diffusion channel 32 may include diffusion through-holes, that is, the second diffusion channel 32 is a diffusion through-hole structure formed in the electrolyte covering layer 20. Of course, in other embodiments, the second diffusion channel 32 may further include a porous filler filled in the diffusion through-holes, that is, the second diffusion channel 32 is a diffusion channel formed by the porous filler filled in the diffusion through-holes. It should be understood that any diffusion channel manner capable of diffusing the gas to be measured is within the protection scope of the setting manner of the second diffusion channel 32 in the embodiments of the present application. In addition, it should be noted that the total number of the second diffusion channels 32, the cross-sectional area of each second diffusion channel 32, and the total cross-sectional area of all the cross-sections of the second diffusion channels 32 are related to the target pump current to be controlled, that is, these parameters are specifically related to the pressure difference in the steady state of diffusion of the gas to be measured between outside and inside the detection chamber 22.

[0053] Exemplarily, the second diffusion channel 32 may be a diffusion slit with a rectangular cross-section. The length of the diffusion slit is 100 μm to 300 μm, and the width of the diffusion slit is 5 μm to 500 μm. Exemplarily, the length of the diffusion slit may be any value between 100 μm and 300 μm, such as 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm. Exemplarily, the width of the diffusion slit may be any value between 5 μm and 50 μm, such as 5 μm, 10 μm, 20 μm, 40 μm, 50 μm. Exemplarily, the number of the diffusion slits may be at least one of any number such as 1, 2, 3, 4, 5, 6, etc. The diffusion slits may be formed by means such as but not limited to laser drilling and mechanical drilling to connect the first diffusion channel 31 and the third diffusion channel 33, so that the gas to be measured can smoothly enter the diffusion barrier 21 and finally enter the detection chamber 22. The size and number of the diffusion slits on the electrolyte covering layer 20 can be adjusted according to the regulation requirements of the pump current. It should be understood that the shape of the second diffusion channel 32 is not limited to the manner of a diffusion slit with a rectangular cross-section. In addition, other manners may also be adopted. For example, a microporous structure may also be adopted as the second diffusion channel 32.

[0054] Exemplarily, the thickness of the electrolyte covering layer 20 is 50 μm to 200 μm. For example, the thickness of the electrolyte covering layer 20 may be any value between 50 μm and 200 μm, such as 50 μm, 75 μm, 100 μm, 125 μm, 150 μm, 175 μm, 200 μm. Compared with the related art where the thickness of the covering layer usually does not exceed 30 microns, the thickness of the electrolyte covering layer 20 in the present application is 50 μm to 200 μm, which is relatively thick, so it is relatively compression-resistant and can also more evenly disperse the pressure in the preparation process, and the product yield is controllable.

[0055] When determining the material of the electrolyte coating 20, various materials can be used. Exemplarily, the material of the electrolyte coating 20 can be yttria- or scandia-doped zirconia ceramics; wherein, the molar mass of yttria or scandia in the zirconia ceramics is 3% to 8%. Exemplarily, the material of the electrolyte coating 20 can be yttria-doped zirconia ceramics, and the molar mass of yttria in the zirconia ceramics can be any value between 3% and 8%, such as 3%, 4%, 5%, 6%, 7%, 8%, etc. Exemplarily, the electrolyte coating 20 can be a dense electrolyte layer formed by sintering, so that in the case where the electrolyte coating 20 has no pores, gas cannot diffuse, and the gas is made to diffuse through a preset second diffusion channel 32 as much as possible, improving the detection accuracy of the oxygen sensor.

[0056] There are various ways to arrange the diffusion barrier 21 and the detection cavity 22 in the accommodation through hole. The following are several exemplary arrangement methods.

[0057] Exemplarily, referring to Figure 1 , a third diffusion channel 33 is provided in the diffusion barrier 21. The third diffusion channel 33 is communicated with the first diffusion channel 31 through the second diffusion channel 32, and the third diffusion channel 33 is communicated with the detection cavity 22 through the diffusion barrier 21, so that the gas to be detected entering from the second diffusion channel 32 enters the detection cavity 22 through the third diffusion channel 33 and the diffusion barrier 21. That is, a third diffusion channel 33 is further provided in the accommodation through hole. The gas to be detected entering from the second diffusion channel 32 first enters the third diffusion channel 33, then enters the diffusion barrier 21 from the third diffusion channel 33, and then enters the detection cavity 22. In this embodiment, the first diffusion channel 31 is used to form the upper end of the gas channel to be detected, and the third diffusion channel 33 is used to form the lower end of the gas channel to be detected. The upper end and the lower end of the gas channel to be detected are communicated through the second diffusion channel 32 in the electrolyte coating 20, thereby realizing the diffusion path for diffusing the gas to be detected to the diffusion barrier 21, which is convenient for controlling the current of the pump cell. When arranging the third diffusion channel 33, referring to Figure 1 , the third diffusion channel 33 can be a diffusion through hole. Of course, in other embodiments, the third diffusion channel 33 can further include a porous filler filled in the diffusion through hole, that is, the third diffusion channel 33 is a diffusion channel formed by the porous filler filled in the diffusion through hole. It should be understood that any diffusion channel method capable of diffusing the gas to be detected is within the protection scope of the arrangement method of the third diffusion channel 33 in the embodiments of the present application.

[0058] Exemplarily, referring to Figure 1, the cross-sectional shape of the diffusion barrier 21 can be annular, that is, the diffusion barrier 21 is an annular layer structure. Exemplarily, the annular shape can be a closed annular shape such as, but not limited to, a circular ring shape. Among them, the third diffusion channel 33 can be a diffusion through-hole at the center of the diffusion barrier 21, and the detection cavity 22 is located outside the diffusion barrier 21. That is, by adopting the annular diffusion barrier 21, the diffusion through-hole at the center of the diffusion barrier 21 is used as the third diffusion channel 33, which is opposite in position and communicated with the second diffusion channel 32. And the detection cavity 22 is located outside the diffusion barrier 21 and is separated from the third diffusion channel 33, so that the gas entering the third diffusion channel 33 needs to pass through the diffusion barrier 21 to enter the detection cavity 22.

[0059] Exemplarily, refer to Figure 1 , the cross-sectional area of the third diffusion channel 33 is larger than the total cross-sectional area of all the second diffusion channels 32. Thus, it is convenient to form a third diffusion channel 33 with a larger size in the diffusion barrier 21, which is convenient for regulating the current of the pump battery. Exemplarily, each second diffusion channel 32 is opposite in position to the third diffusion channel 33, which is convenient for the gas to be measured in the second diffusion channel 32 to smoothly diffuse into the third diffusion channel 33. Exemplarily, the cross-sectional size of the third diffusion channel 33 is larger than the cross-sectional size of each second diffusion channel 32, and each second diffusion channel 32 is opposite in position to the third diffusion channel 33. Thus, it is convenient to form a third diffusion channel 33 with a larger size in the diffusion barrier 21, which is convenient for regulating the current of the pump battery.

[0060] Exemplarily, refer to Figure 1 , the third diffusion channel 33 can have the same cross-sectional size as the first diffusion channel 31 and be opposite in cross-sectional position. That is, the cross-sectional shape of the third diffusion channel 33 is exactly the same as the cross-sectional shape of the first diffusion channel 31, and the positions are exactly opposite, so as to reduce the influence of pressure concentration at the hole edge of the first diffusion channel 31 on the electrolyte covering layer 20 and the diffusion barrier 21.

[0061] It should be understood that the second diffusion channel 32 is not limited to the way of being connected to the diffusion barrier 21 through the third diffusion channel 33. In addition, other ways can also be adopted.

[0062] Exemplarily, refer to Figure 2 and Figure 3Each second diffusion channel 32 can be positioned opposite the diffusion barrier 21, with the space in the accommodating through-hole excluding the diffusion barrier 21 forming a detection cavity 22. This allows the gas to enter through the second diffusion channel 32 through the diffusion barrier 21 and into the detection cavity 22. In this manner, the diffusion barrier 21 directly opposes the second diffusion channel 32, allowing the gas to enter through the second diffusion channel 32 to directly enter the diffusion barrier 21 and, through it, into the detection cavity 22. In this case, the arrangement of the diffusion barrier 21 and the detection cavity 22 can also be implemented in a variety of ways.

[0063] Exemplary, reference Figure 2 The receiving through-hole can be a large circular through-hole with a large cross-section. The diffusion barrier 21 can be disc-shaped, with a smaller cross-sectional area than the receiving through-hole. The diffusion barrier 21 is positioned opposite the second diffusion channel 32, eliminating the need for a third diffusion channel 33 within the diffusion barrier 21. The detection chamber 22 is an annular chamber, meaning that the diffusion barrier 21 is located exactly in the center of the receiving through-hole.

[0064] Exemplary, reference Figure 3 The receiving through-hole can be a large rectangular cross-section. The diffusion barrier 21 can be rectangular, with a smaller cross-sectional area than the receiving through-hole. The diffusion barrier 21 is positioned opposite the second diffusion channel 32, eliminating the need for the third diffusion channel 33 within the diffusion barrier 21. Furthermore, the diffusion barrier 21 is located to the left of the receiving through-hole, while the detection chamber 22 is located to the right.

[0065] Exemplary, reference Figures 1 to 3 A test electrode 43 is disposed on the surface of the first electrolyte layer 11 facing away from the electrolyte cover layer 20, and a common electrode is disposed in the detection cavity 22. The pump cell of the oxygen sensor includes the test electrode 43 and the common electrode, forming an oxygen pump unit including the test electrode 43 and the common electrode. Exemplarily, an electrode protective layer 51 may be provided on the surface of the test electrode 43 to protect the test electrode 43. Exemplarily, the electrode protective layer 51 may be porous zirconia or porous alumina, and the porosity of the electrode protective layer 51 may be 15% to 45%.

[0066] Exemplary, reference Figures 1 to 3 The oxygen sensor further includes a reference chamber 23 for accommodating a reference gas. A reference electrode 44 is provided in the reference chamber 23. The Nernst cell of the oxygen sensor includes a reference electrode 44 and a common electrode.

[0067] Exemplary, reference Figures 1 to 3, the common electrode in the detection chamber 22 may include a first common electrode 41 and a second common electrode 42. Among them, the first common electrode 41 is located above the detection chamber 22, and the second common electrode 42 is located below the detection chamber 22. Exemplarily, the first common electrode 41 may be disposed on the lower surface of the electrolyte covering layer 20, and the second common electrode 42 may be disposed on the upper surface of another electrolyte layer and is opposite to the position of the first common electrode 41. Exemplarily, the pump cell of the oxygen sensor may include the first common electrode 41 and the test electrode 43. Exemplarily, the Nernst cell of the oxygen sensor may include the reference electrode 44 and the second common electrode 42. Of course, in other embodiments, only the above-mentioned first common electrode 41 or second common electrode 42 may be provided.

[0068] There are various ways to set up the reference chamber 23. The following are several exemplary ways of setting up.

[0069] Exemplarily, refer to Figure 3 , the reference chamber 23 may be disposed in the second electrolyte layer 12, and the reference chamber 23 is separated from the detection chamber 22 by the second electrolyte layer 12. Exemplarily, the reference chamber 23 may be separated from the accommodation through hole by the second electrolyte layer 12, so as to ensure that the reference chamber 23 is separated from the detection chamber 22 by the second electrolyte layer 12. That is, the detection chamber 22 and the reference chamber 23 are located in the same electrolyte layer. Exemplarily, two cavities are provided in the second electrolyte layer 12, and the two cavities are separated by the second electrolyte layer 12. One of the cavities is used as the accommodation through hole to set up the diffusion barrier 21 and the detection chamber 22. The other cavity is used as the reference chamber 23 for accommodating the reference gas. Of course, in other embodiments, the reference chamber 23 may also be a notch at the edge of the second electrolyte layer 12, that is, the opening of the reference chamber 23 is exactly the notch opening at the edge of the second electrolyte layer 12, so as to facilitate the reference gas to enter the reference chamber 23. Exemplarily, the reference electrode 44 is disposed on the upper cavity wall of the reference chamber 23. Of course, the reference electrode 44 may also be disposed on the lower cavity wall of the reference chamber 23.

[0070] Exemplarily, the reference chamber 23 may also be disposed at a position in a different electrolyte layer from the detection chamber 22. Exemplarily, the reference chamber 23 may also be disposed below the detection chamber 22. Exemplarily, refer to Figure 1 and Figure 2 , the third electrolyte layer 13 may be laminated on the surface of the second electrolyte layer 12 facing away from the electrolyte covering layer 20, and the fourth electrolyte layer 14 may be laminated on the surface of the third electrolyte layer 13 facing away from the second electrolyte layer 12, and the reference chamber 23 is disposed in the fourth electrolyte layer 14. Exemplarily, the reference electrode 44 may be disposed on the lower surface of the third electrolyte layer 13.

[0071] Exemplarily, refer toFigures 1 to 3 , the oxygen sensor may further include a heating unit for heating structures in, such as but not limited to, the reference cavity 23 and the detection cavity 22. When setting the heating unit, various methods can be adopted.

[0072] Exemplarily, referring to Figures 1 to 3 , the heating unit may include: a heating electrode 45, an insulating layer 52, and a fifth electrolyte layer 15. Among them, a cavity is provided in the fifth electrolyte layer 15, the heating electrode 45 is arranged in the cavity, and the heating electrode 45 is separated from the fifth electrolyte layer 15 by the insulating layer 52, that is, the heating electrode 45 is surrounded by the insulating layer 52. The material of the insulating layer 52 can be, such as but not limited to, alumina ceramic. Exemplarily, the porosity of the alumina ceramic as the insulating layer 52 can be less than 1%. Exemplarily, referring to Figure 1 , the fifth electrolyte layer 15 can be laminated on the surface of the fourth electrolyte layer 14 facing away from the third electrolyte layer 13. Exemplarily, referring to Figure 2 , the fifth electrolyte layer 15 can be laminated on the surface of the third electrolyte layer 13 facing away from the second electrolyte layer 12.

[0073] Exemplarily, the material of any one of the test electrode 43, the common electrode, the reference electrode 44, and the heating electrode 45 can be a platinum cermet electrode. Exemplarily, the mass fraction of platinum in the platinum cermet electrode can be 40% - 60%.

[0074] Exemplarily, the material of any one of the above electrolyte layers can be zirconia ceramic doped with yttrium oxide or scandium oxide. Exemplarily, the molar mass of yttrium oxide or scandium oxide in the zirconia ceramic is 3% - 8%. Exemplarily, any one of the above electrolyte layers can be a dense electrolyte layer formed by sintering. Thus, in the case where the electrolyte layer has no pores, gas cannot diffuse, and the gas is made to diffuse as much as possible through preset diffusion channels such as but not limited to the diffusion barrier 21, improving the detection accuracy of the oxygen sensor.

[0075] In the various embodiments shown above, by adding an electrolyte covering layer 20 between the first electrolyte layer 11 and the second electrolyte layer 12, during the lamination molding process of the oxygen sensor, the pressure distribution of the electrolyte covering layer 20 on the diffusion barrier 21 is relatively uniform, preventing the diffusion barrier 21 from cracking and improving the product yield. It avoids the cracking or deformation of the covering layer or the diffusion barrier 21 during the subsequent molding process of the oxygen sensor due to the small covering area and size of the covering layer above the diffusion barrier 21, resulting in the diffusion barrier 21 not being tightly sealed or the covering being incomplete, which brings difficulties to the regulation of the pump current of the oxygen sensor. Moreover, the oxygen sensor shown in the embodiments of the present application has a simpler structure, is easier to manufacture, has a better sealing effect, and improves the regulation accuracy of the pump current. It reduces the manufacturing difficulty of the oxygen sensor and also improves the manufacturing yield and control accuracy of the oxygen sensor.

[0076] In addition, an embodiment of the present application further provides a manufacturing method of an oxygen sensor. Referring to Figures 1 to 3 , the manufacturing method includes:

[0077] Form a first diffusion channel 31 in the first electrolyte layer 11;

[0078] Form a diffusion barrier 21 and a detection cavity 22 in the second electrolyte layer 12;

[0079] Form at least one second diffusion channel 32 in the electrolyte covering layer 20; and the total cross-sectional area of all the second diffusion channels 32 is smaller than the cross-sectional area of the first diffusion channel 31;

[0080] Stack the first electrolyte layer 11, the electrolyte covering layer 20, and the second electrolyte layer 12 in sequence; the diffusion barrier 21 is at least connected to the first diffusion channel 31 through the second diffusion channel 32, and the detection cavity 22 is at least connected to the second diffusion channel 32 through the diffusion barrier 21.

[0081] In the above solution, by adding an electrolyte covering layer 20 between the first electrolyte layer 11 and the second electrolyte layer 12, during the stacking and molding process of the oxygen sensor, the pressure distribution of the electrolyte covering layer 20 on the diffusion barrier 21 is relatively uniform, preventing the diffusion barrier 21 from cracking and improving the product yield. The following will introduce each of the above steps in detail with reference to the accompanying drawings.

[0082] It should be noted that the step of forming the first diffusion channel 31 in the first electrolyte layer 11 and the step of forming the diffusion barrier 21 and the detection cavity 22 in the second electrolyte layer 12 are not in a sequential order and can be carried out simultaneously or separately. The step of setting the second diffusion channel 32 in the electrolyte covering layer 20 and the step of stacking the first electrolyte layer 11, the electrolyte covering layer 20, and the second electrolyte layer 12 in sequence are not in a sequential order. For example, the second diffusion channel 32 can be set in the electrolyte covering layer 20 first, and then the first electrolyte layer 11, the electrolyte covering layer 20, and the second electrolyte layer 12 are stacked in sequence; or the first electrolyte layer 11, the electrolyte covering layer 20, and the second electrolyte layer 12 can be stacked in sequence first, and then the second diffusion channel 32 is set in the electrolyte covering layer 20.

[0083] Among them, when forming the first diffusion channel 31 in the first electrolyte layer 11, various methods can be adopted. Exemplarily, the first diffusion channel 31 can be formed in the first electrolyte layer 11 by means such as laser drilling and mechanical drilling.

[0084] The diffusion barrier 21 and the detection cavity 22 can be arranged in the second electrolyte layer 12 in a variety of ways. Exemplarily, the second electrolyte layer 12 can be provided with accommodation through-holes, that is, the accommodation through-holes penetrate the two opposite upper and lower surfaces of the second electrolyte layer 12. The diffusion barrier 21 and the detection cavity 22 are arranged in the accommodation through-holes, that is, the diffusion barrier 21 and the detection cavity 22 are arranged inside the accommodation through-holes. Among them, when forming the accommodation through-holes in the second electrolyte layer 12, a variety of ways can be adopted. Exemplarily, ways such as laser drilling, mechanical drilling, etc. can be used to form the accommodation through-holes in the second electrolyte layer 12. The diffusion barrier 21 can be formed in the accommodation through-holes in a variety of ways. Exemplarily, the diffusion barrier 21 shown in the above oxygen sensor part can be formed in the accommodation through-holes by processes such as but not limited to screen printing process, filling process. During the process of forming the diffusion barrier 21, the detection cavity 22 can be formed simultaneously.

[0085] Among them, the at least one second diffusion channel 32 can be arranged in the electrolyte cover layer 20 in a variety of ways. Exemplarily, ways such as laser drilling, mechanical drilling, etc. can be used to form the second diffusion channel 32 in the electrolyte cover layer 20.

[0086] The positions of the first diffusion channel 31, the second diffusion channel 32, and the accommodation through-holes can be adjusted. After successively laminating the first electrolyte layer 11, the electrolyte cover layer 20, and the second electrolyte layer 12 by laminating and molding, it is ensured that each second diffusion channel 32 is opposite to the position of the first diffusion channel 31, the diffusion barrier 21 is at least connected to the first diffusion channel 31 through the second diffusion channel 32, and the detection cavity 22 is at least connected to the second diffusion channel 32 through the diffusion barrier 21, so that the gas to be measured enters the detection cavity 22 at least through the first diffusion channel 31, the second diffusion channel 32, and the diffusion barrier 21.

[0087] Exemplarily, after successively laminating the first electrolyte layer 11, the electrolyte cover layer 20, and the second electrolyte layer 12, and then forming structures such as but not limited to the reference cavity 23, the heating unit, etc., the laminated structure can be sintered together to form an oxygen sensor.

[0088] Exemplarily, before forming at least one second diffusion channel 32 in the electrolyte cover layer 20, the manufacturing method can further include: sintering the successively laminated first electrolyte layer 11, electrolyte cover layer 20, and second electrolyte layer 12. That is, after sintering the successively laminated first electrolyte layer 11, electrolyte cover layer 20, and second electrolyte layer 12, at least one second diffusion channel 32 is formed in the electrolyte cover layer 20. Exemplarily, the first diffusion channel 31 can be formed in the first electrolyte layer 11, and the diffusion barrier 21 and the detection cavity 22 can be formed in the second electrolyte layer 12, and then the successively laminated first electrolyte layer 11, electrolyte cover layer 20, and second electrolyte layer 12 can be sintered.

[0089] Furthermore, an embodiment of the present application also provides an engine. Referring to Figures 1 to 3 , the engine includes any one of the above oxygen sensors. Exemplarily, the engine may include an exhaust pipe, and the oxygen sensor may be disposed in the exhaust pipe of the engine to detect the oxygen concentration in the engine exhaust.

[0090] In addition, an embodiment of the present application also provides a vehicle. Referring to Figures 1 to 3 , the vehicle includes any one of the above oxygen sensors, or any one of the above engines. Exemplarily, the oxygen sensor may be disposed in the cockpit of the vehicle to detect the oxygen concentration in the cockpit. Exemplarily, when the vehicle includes any one of the above engines, the vehicle may be, for example but not limited to, a fuel vehicle, a hybrid vehicle, etc.

[0091] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are only for the purpose of exemplification and illustration, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of protection required by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalent scope.

Claims

1. An oxygen sensor, characterized in that, Comprising: A first electrolyte layer, an electrolyte covering layer, and a second electrolyte layer stacked in sequence; Wherein, a first diffusion channel is provided in the first electrolyte layer; At least one second diffusion channel is provided in the electrolyte covering layer; and the total cross-sectional area of all the second diffusion channels is smaller than the cross-sectional area of the first diffusion channel; A diffusion barrier and a detection cavity are provided in the second electrolyte layer, the diffusion barrier is communicated with the first diffusion channel at least through the second diffusion channel, and the detection cavity is communicated with the second diffusion channel at least through the diffusion barrier.

2. The oxygen sensor according to claim 1, wherein Each of the second diffusion channels is opposite to the first diffusion channel in position.

3. The oxygen sensor according to claim 1, wherein A third diffusion channel is provided in the diffusion barrier, the third diffusion channel is communicated with the first diffusion channel through the second diffusion channel, and the third diffusion channel is communicated with the detection cavity through the diffusion barrier.

4. The oxygen sensor according to claim 3, wherein The cross-sectional shape of the diffusion barrier is annular; Wherein, the third diffusion channel is a diffusion through-hole at the center of the diffusion barrier, and the detection cavity is located outside the diffusion barrier.

5. The oxygen sensor according to claim 3, characterized in that, The cross-sectional area of the third diffusion channel is larger than the total cross-sectional area of all the second diffusion channels, and each of the second diffusion channels is opposite to the third diffusion channel in position.

6. The oxygen sensor according to claim 3, characterized in that, The cross-sectional dimensions of the third diffusion channel and the first diffusion channel are equal and the cross-sectional positions are opposite.

7. The oxygen sensor according to claim 1, characterized in that, An accommodation through-hole is provided in the second electrolyte layer, and the diffusion barrier and the detection cavity are provided in the accommodation through-hole.

8. The oxygen sensor according to claim 7, wherein Each of the second diffusion channels is opposite to the diffusion barrier in position, and the space in the accommodation through-hole except the diffusion barrier forms the detection cavity.

9. The oxygen sensor according to claim 1, characterized in that, The first diffusion channel is a diffusion through-hole, and / or, the second diffusion channel is a diffusion through-hole.

10. The oxygen sensor according to claim 1, characterized in that, The second diffusion channel is a diffusion slit, the cross-section of the diffusion slit is rectangular, the length of the diffusion slit is 100 μm to 300 μm, and the width of the diffusion slit is 5 μm to 50 μm.

11. The oxygen sensor according to claim 1, characterized in that, The thickness of the electrolyte covering layer is 50 μm to 200 μm.

12. The oxygen sensor according to claim 1, characterized in that, The material of the electrolyte covering layer is zirconia ceramic doped with yttrium oxide or scandium oxide; wherein, the molar mass of yttrium oxide or scandium oxide in the zirconia ceramic is 3% to 8%.

13. The oxygen sensor according to any one of claims 1 to 12, characterized in that, A test electrode is provided on the surface of the first electrolyte layer facing away from the electrolyte covering layer, a common electrode is provided in the detection cavity, and the pump cell of the oxygen sensor includes the test electrode and the common electrode.

14. The oxygen sensor according to any one of claims 1 to 12, characterized in that A reference cavity is further included, the reference cavity is used for accommodating a reference gas, a reference electrode is provided in the reference cavity, and the Nernst cell of the oxygen sensor includes the reference electrode and the common electrode.

15. The oxygen sensor according to claim 14, characterized in that, The reference cavity is provided in the second electrolyte layer, and the reference cavity and the detection cavity are separated by the second electrolyte layer.

16. The oxygen sensor according to claim 15, characterized in that, The reference cavity is a notch at the edge of the second electrolyte layer.

17. A manufacturing method of an oxygen sensor, characterized in that, Comprising: Forming a first diffusion channel in the first electrolyte layer; Forming a diffusion barrier and a detection cavity in the second electrolyte layer; Forming at least one second diffusion channel in the electrolyte covering layer; And the total cross-sectional area of all the second diffusion channels is smaller than the cross-sectional area of the first diffusion channel; Stack the first electrolyte layer, the electrolyte covering layer, and the second electrolyte layer in sequence; the diffusion barrier is communicated with the first diffusion channel at least through the second diffusion channel, and the detection cavity is communicated with the second diffusion channel at least through the diffusion barrier.

18. The manufacturing method according to claim 17, characterized in that, Before forming at least one second diffusion channel in the electrolyte covering layer, the manufacturing method further includes: Sinter the first electrolyte layer, the electrolyte covering layer, and the second electrolyte layer stacked in sequence.

19. An engine, characterized in that, Comprising: The oxygen sensor according to any one of claims 1 to 16.

20. A vehicle, characterized in that, Comprising: The oxygen sensor according to any one of claims 1 to 16, or the engine according to claim 19.

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