Oxygen sensor chip with built-in reaction cavity

Abstract

The utility model provides an oxygen sensor chip with a built-in reaction cavity. The oxygen sensor chip consists of a plurality of layers of green ceramic chips which are pressed together, a plurality of layers of green ceramic chips in the oxygen sensor chip are reaction cavity layers, a plurality of layers of green ceramic chips on the upper layer of the reaction cavity layers are heater layers, a plurality of layers of green ceramic chips on the lower layer of the reaction cavity layers are electrode layers, and an annular airflow channel communicated with two ends of a reaction cavity is arranged on the outer surface of each reaction cavity layer. After to-be-detected gas enters the reaction cavity layer, the to-be-detected gas is subjected to heating reaction through the heater layer on the upper layer of the reaction cavity layer, the oxygen content in the heated to-be-detected gas is changed, and the heated gas in the reaction cavity layer and unheated gas outside the oxygen sensor chip are subjected to oxygen content difference value-to-electric signal difference value output through the electrode layer. The reaction cavity layer is tightly attached to the heater layer and the electrode layer, so that gas heating reaction and oxygen content detection can be quickly carried out, and the oxygen sensor chip is high in integration level, simple in structure and high in sensitivity.

Description

Technical Field

[0001] The utility model relates to an oxygen sensor chip, in particular to an oxygen sensor chip with a built-in reaction cavity. Background Art

[0002] The chip-type oxygen sensor is a relatively new type of oxygen sensor. It has the advantages of short response time, small size, low manufacturing cost, and reliable performance. It is an important component for the automotive industry to achieve energy conservation (improve fuel economy) and emission reduction (reduce harmful gas emissions from automobile exhaust). The oxygen sensor chip is the core of the chip-type oxygen sensor and also the component that plays a major role. The oxygen sensor can measure the oxygen content in the engine exhaust and determine whether the gasoline and air are completely burned. The electronic controller implements closed-loop control with the excess air coefficient λ=1 as the target based on the feedback information of the oxygen sensor to ensure that the three-way catalytic converter can completely burn HC, CO and NO in the exhaust. x All three pollutants have maximum conversion efficiency.

[0003] As domestic oxygen sensor technology continues to mature, more and more companies are attempting to manufacture limiting current oxygen sensors with built-in cavities. A popular manufacturing method involves printing a carbon-based slurry, which forms a cavity after sintering. However, this method has the disadvantage that the reverse pump current requires a cavity volume of approximately 30% of the overall volume, making it difficult to meet this requirement with printing. Oxygen sensor chips must have a sufficiently large cavity volume to meet the reverse pump current requirements of limiting current oxygen sensors. Furthermore, the cavity in limiting current chip oxygen sensors supplies oxygen to the reverse electrode, increasing the oxygen flow rate in the cavity and, consequently, the reverse current value, making it easier to identify and process oxygen content. However, the cavities in mainstream oxygen sensors are mostly open on one side or connected to the intake duct on one side. This has the disadvantage of limiting the oxygen flow rate, which affects the reverse current value. Utility Model Content

[0004] The utility model aims to overcome the problems in the prior art that the cavity volume of the oxygen sensor chip cannot meet the reverse pump current requirements of the limiting current type oxygen sensor and how to ensure the oxygen flow rate in the cavity. An oxygen sensor chip with a built-in reaction cavity is provided. The oxygen sensor chip provided by the utility model has a reaction cavity layer in which the reaction cavity volume can reach a maximum of 60%, which is fully capable of meeting the requirements of the limiting current type oxygen sensor for the reverse pump current on the built-in cavity volume. In addition, annular airflow channels are connected at both ends of the reaction cavity to ensure the circulation of oxygen in the reaction cavity, thereby improving the oxygen flow rate.

[0005] To achieve the above object, the present utility model provides an oxygen sensor chip with an internal reaction cavity. The oxygen sensor chip is composed of multiple layers of green ceramic chips pressed together; several layers of green ceramic chips in the oxygen sensor chip are reaction cavity layers, and reaction cavities are provided in the reaction cavity layers; an annular air flow channel communicating with both ends of the reaction cavity is provided on the outer surface of the reaction cavity layer; several layers of green ceramic chips above the reaction cavity layer are heater layers, and several layers of green ceramic chips below are electrode layers; heating electrodes are provided on the heater layers; and test electrodes are provided on the electrode layers. After the gas to be detected enters the reaction cavity layer, it undergoes a heating reaction through the heater layer above the reaction cavity layer. The oxygen content in the heated gas to be detected changes. The difference in oxygen content between the heated gas in the reaction cavity layer and the unheated gas outside the oxygen sensor chip is converted into a difference in electrical signal and output through the electrode layer, enabling the detection of data inside and outside the chip to obtain the oxygen content of the gas. For example, in automotive exhaust gas detection, the exhaust gas is heated by the heater layer in the oxygen sensor to burn out the excess oxygen, and the oxygen content is compared with that of the unburned exhaust gas outside the oxygen sensor to further determine whether the gasoline and air are completely burned. The reaction cavity layer is in close contact with the heater layer and the electrode layer, enabling rapid heating of the gas reaction and detection of the oxygen content, achieving an oxygen sensor chip with high integration, simple structure, and high sensitivity.

[0006] Preferably, the depth of the annular air flow channel is 0.01 - 0.05 mm.

[0007] The beneficial effects of the above preference are as follows: Both sides of the reaction cavity are connected to the outside through the annular air flow channel, enabling gas exchange with the outside and maintaining the air pressure balance inside and outside the chip, ensuring that the oxygen flow rate in the reaction cavity can increase the reverse current value. At the same time, the depth of the annular air flow channel is only 0.01 mm - 0.05 mm, with a relatively narrow gap, ensuring a limited exchange volume while exchanging gas with the outside, not affecting the oxygen content of the heated gas in the reaction cavity, and ensuring the accuracy of the test results.

[0008] Preferably, the width of the annular air flow channel is 0.5 - 2.7 mm.

[0009] Preferably, the reaction cavity in the reaction cavity layer is located in the middle of the reaction cavity layer.

[0010] Preferably, the length of the reaction cavity is 24 - 30 mm, the width is 2.1 - 2.7 mm, and the thickness is 0.3 - 0.6 mm.

[0011] Preferably, the thickness of the oxygen sensor chip is 1.0 - 2.0 mm, the length is 40 - 50 mm, and the width is 3.5 - 4.5 mm.

[0012] The above preferred beneficial effects are as follows: The oxygen sensor is small in volume, can be widely applied to various scenarios, and has a small product volume with low heating power consumption, which is convenient for processing and has high processing efficiency.

[0013] Preferably, the volume of the reaction cavity accounts for 40% - 60% of the oxygen sensor chip.

[0014] The above preferred beneficial effects are as follows: The maximum volume of the reaction cavity can reach 60% to meet the requirements of the reverse pumping current of the limiting current type oxygen sensor, and the detection efficiency of the oxygen sensor chip can be higher.

[0015] Preferably, the reaction cavity layer has 3 - 6 green ceramic sheets.

[0016] More preferably, in the present utility model, the reaction cavity layer is made by stacking 4 green ceramic sheets.

[0017] Preferably, the heater layer has 1 - 5 green ceramic sheets; the electrode layer has 2 - 5 green ceramic sheets.

[0018] More preferably, in the present utility model, the heater layer is made by stacking 4 green ceramic sheets, and the electrode layer is made by stacking 4 green ceramic sheets.

[0019] Preferably, the heater layer and the electrode layer are provided with through holes.

[0020] The above preferred beneficial effects are as follows: Each layer of green ceramic sheet is in contact with the gas, increasing the contact reaction area and improving the accuracy of the detection result.

[0021] Therefore, the present utility model has the following beneficial effects: (1) The built-in reaction cavity of the oxygen sensor chip proposed by the present utility model can be up to 60% of the product volume at most, which can fully meet the requirements of the reverse pumping current of the limiting current type oxygen sensor for the volume of the built-in reaction cavity. (2) The annular air flow channels on both sides of the built-in reaction cavity of the oxygen sensor chip proposed by the present utility model can improve the oxygen flow rate and thus increase the reverse current value while ensuring the air pressure balance inside and outside the oxygen sensor chip, making it easier to identify and detect the oxygen content. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of an oxygen sensor chip with a built-in large cavity of the present utility model.

[0023] 1 - heater layer; 2 - reaction cavity layer; 3 - electrode layer; 4 - annular air flow channel; 5 - through hole. Detailed Embodiments

[0024] The following further describes the present utility model in conjunction with the drawings and specific embodiments.

[0025] As Figure 1An oxygen sensor chip with a built-in reaction cavity is shown. The oxygen sensor chip is composed of multiple green ceramic chips pressed together. Several layers of green ceramic chips in the oxygen sensor chip are the reaction cavity layer 2, and a reaction cavity is provided in the reaction cavity layer 2. An annular air flow channel 4 communicating with both ends of the reaction cavity is provided on the outer surface of the reaction cavity layer. Several layers of green ceramic chips above the reaction cavity layer are the heater layer 1, and several layers of green ceramic chips below are the electrode layer 3. A heating electrode is provided on the heater layer 1, and a test electrode is provided on the electrode layer 3. The oxygen sensor chip is square, with a thickness of 1.0 - 2.0 mm, a single-side length of 40 - 50 mm, and a width of 3.5 - 4.5 mm. From top to bottom are the heater layer 1, the reaction cavity layer 2, and the electrode layer 3 in sequence. The green ceramic chips of the heater layer 1 and the electrode layer 3 are punched, and the green ceramic chips of the reaction cavity layer 2 are cavity-punched. The obtained reaction cavity has a length of 24 - 30 mm and a thickness of 0.3 - 0.6 mm. It can be achieved that the volume of the reaction cavity accounts for 40% - 60% of the oxygen sensor chip. After the gas to be detected enters the reaction cavity layer 2, it undergoes a heating reaction through the heater layer 1 above the reaction cavity layer 2. The oxygen content in the heated gas to be detected changes. The electrode layer 3 is used to convert the oxygen content between the heated gas in the reaction cavity and the unheated gas outside the oxygen sensor chip into a voltage to reflect the voltage difference inside and outside the chip, thereby obtaining the oxygen content of the gas to determine whether gasoline and air are completely burned. The reaction cavity layer is in close contact with the heater layer and the electrode layer, which can quickly carry out the heating gas reaction and detect the oxygen content, achieving an oxygen sensor chip with high integration, simple structure, and high sensitivity. Through the expansion of the reaction cavity volume by the present utility model, the reaction cavity with a maximum volume accounting for 60% of the total volume can be achieved, which can play a larger reaction cavity in practical applications to meet the role of the reverse pump current of the limiting current type oxygen sensor in practical applications.

[0026] In a specific embodiment of the present utility model, the depth of the annular air flow channel is 0.01 - 0.05 mm. Both sides of the reaction cavity are connected to the outside through the gaps formed by the annular air flow channel, which can achieve gas exchange with the outside and maintain the air pressure balance inside and outside the chip, ensuring that the oxygen flow rate in the reaction cavity can increase the reverse current value and making it easier to detect the oxygen content. At the same time, the depth of the annular air flow channel is only 0.01 mm - 0.05 mm, and the generated gap is relatively narrow. While exchanging gas with the outside, it ensures that the exchange amount is limited, does not affect the oxygen content of the heated gas in the reaction cavity, and guarantees the accuracy of the test results.

[0027] In a specific embodiment of the present utility model, the width of the annular air flow channel is 0.5 - 2.7 mm. In specific applications, the present utility model selects a width equal to that of the reaction cavity. Under the condition of ensuring high gas flow efficiency, it reduces the influence on the detection results. If the width of the annular air flow channel is greater than that of the reaction cavity, there is a probability that the unheated gas will directly enter the electrode layer and affect the detection data.

[0028] In a specific embodiment of the present utility model, the thickness of the oxygen sensor chip is 1.0 - 2.0 mm, the length is 40 - 50 mm, and the width is 3.5 - 4.5 mm. The oxygen sensor is small in volume, can be widely applied to various scenarios, and has low heating power consumption due to its small size, which is convenient for processing and has high processing efficiency.

[0029] In a specific embodiment of the present utility model, the reaction cavity in the reaction cavity layer is located in the middle of the reaction cavity layer.

[0030] In a specific embodiment of the present utility model, the length of the reaction cavity is 24 - 30 mm, the width is 2.1 - 2.7 mm, and the thickness is 0.3 - 0.6 mm.

[0031] In a specific embodiment of the present utility model, the volume of the reaction cavity accounts for 40% - 60% of the oxygen sensor chip. The maximum cavity volume can reach 60% to meet the requirements of the reverse pump current of the limiting current type oxygen sensor, and the detection efficiency of the oxygen sensor chip can be made higher.

[0032] In a specific embodiment of the present utility model, the reaction cavity layer is composed of 3 - 6 green ceramic sheets. In the present utility model, the reaction cavity layer is made by stacking 4 green ceramic sheets.

[0033] In a specific embodiment of the present utility model, the heater layer is composed of 1 - 5 green ceramic sheets; the electrode layer is composed of 2 - 5 green ceramic sheets. In the present utility model, the heater layer is made by stacking 4 green ceramic sheets, and the electrode layer is made by stacking 4 green ceramic sheets.

[0034] In a specific embodiment of the present utility model, the heater layer 1 and the electrode layer 3 are provided with through holes 5. Each layer of green ceramic sheet is in contact with gas, increasing the contact reaction area and improving the accuracy of the detection result.

[0035] Example 1:

[0036] As Figure 1 shown, an oxygen sensor chip with an internal reaction cavity, the oxygen sensor chip includes a cavity layer, a heating layer and an electrode layer. At the same time, the oxygen sensor chip is made by stacking multiple layers of green ceramic sheets. The green ceramic sheets selected are alumina - based green ceramic sheets and zirconia - based green ceramic sheets. The 5th - 8th layers of green ceramic sheets in the middle of the oxygen sensor chip are the cavity layer, the 1st - 4th layers of green ceramic sheets above the cavity layer are the heater layer, and the lower part of the cavity layer is connected with the electrode layer. The oxygen sensor chip is square, with a thickness of 1.5 mm, a single - side length of 46 mm, and a width of 4.1 mm. From top to bottom, there are the heater layer, the cavity layer and the electrode layer in sequence. The green ceramic sheets of the heater layer and the electrode layer are punched, and the green ceramic sheets of the large cavity layer are cavity - punched. The obtained cavity has a length of 24 mm and a thickness of 0.3 mm. The cavity volume can account for 40% of the oxygen sensor chip.

[0037] In Example 1, 11 green ceramic chips made of alumina with a thickness of 185 μm and 1 green ceramic chip made of zirconia with a thickness of 185 μm were selected. The green ceramic chips were formed by tape casting after grinding, drying, and mixing of alumina powder and zirconia powder, and the composition content was 90-99 wt% ceramic.

[0038] The preparation process of the oxygen sensor chip includes the following steps:

[0039] (1) Provide green ceramic chips: Prepare 11 green ceramic chips made of alumina with a thickness of 185 μm; Prepare 1 green ceramic chip made of zirconia with a thickness of 185 μm; Number the green ceramic chips in sequence and bake and cure them using the parameters of 60 °C / 15 min.

[0040] (2) Punching / cavity punching: The green ceramic chips are distinguished according to the functional layers: Layers 1-4 are the heater layer, layers 5-8 are the cavity layer, and layers 9-12 are the electrode layer; Punching operations are performed on the green ceramic chips of the heater layer and the electrode layer, and cavity punching operations are performed on the green ceramic chips of the large cavity layer.

[0041] (3) Inner electrode printing: Perform inner electrode printing operations on the green ceramic chips of the heater layer and the electrode layer according to the pattern requirements. The heating electrode is printed on the heater layer, and the test electrode is printed on the electrode layer.

[0042] (4) Glue spraying / segmented lamination: Perform glue spraying / lamination operations on the green ceramic chips of the heater layer, the cavity layer, and the electrode layer respectively.

[0043] (5) Warm water isostatic pressing with large pressure for shaping: Use the temperature (80 °C), preheating (10 min), time (40 MPa / 20 min) pressure parameters to complete the shaping step during the operation. The heater layer, the cavity layer, and the electrode layer are shaped to obtain the corresponding segmented blocks.

[0044] (6) Glue spraying / combined pressure lamination: Evenly spray a mixture of pvb with a content of (10%) and absolute ethanol on the interface of the segmented blocks. Use a glue spraying device to evenly spray glue particles with a diameter of (1 to 3 μm) and a density of (60%) on the surface of the block segments. Then, according to the combined pressure sequence of the production plan, use a process of (10 t) pressure for lamination for (10 s), and the heating temperature of the upper and lower platforms is (50 °C) for combined pressure lamination.

[0045] (7) Warm water isostatic pressing with small pressure for combined pressure: Then use a warm water isostatic press to preheat (10 min) at (80 °C) and then apply a pressure of (15 MPa), and keep the pressure for (40 min) to further strengthen the interface bonding between the segmented blocks to prepare the oxygen sensor chip.

[0046] Example 2:

[0047] As Figure 1The oxygen sensor chip shown here features a built-in reaction cavity. The chip comprises a cavity layer, a heating layer, and an electrode layer. The chip is made by laminating multiple layers of green ceramic sheets made of alumina and zirconia. The fifth to ninth layers in the middle of the chip serve as the cavity layer, while the first four layers above the cavity layer serve as the heater layer. Below the cavity layer, 10 to 13 layers of green ceramic sheets form the electrode layer. The chip is square, 1.0 mm thick, 40 mm long on a single side, and 3.5 mm wide. From top to bottom, the chip comprises the heater layer, cavity layer, and electrode layer. The green ceramic sheets for the heater and electrode layers are punched, while the green ceramic sheet for the large cavity layer is punched. The resulting cavity is 24 mm long and 0.3 mm thick. This ensures that the cavity accounts for 40% of the total volume of the oxygen sensor chip.

[0048] In Example 2, 12 185 μm thick alumina green ceramic sheets and one 185 μm thick zirconia green ceramic sheet were selected. The green ceramic sheets were formed by tape casting of alumina powder and zirconia powder after grinding, drying, and mixing, and the content of the raw ceramic sheets was 90-99 wt %.

[0049] The oxygen sensor chip preparation process includes the following steps:

[0050] (1) Providing green ceramic sheets: Prepare 12 185 μm thick alumina green ceramic sheets; prepare 1 185 μm thick zirconia green ceramic sheet; label the green ceramic sheets in order and bake and cure them at a temperature of 60°C / 15 min.

[0051] (2) Punching / cavitation: The green ceramic sheets are divided into functional layers: layers 1 to 4 are heater layers, layers 5 to 9 are cavity layers, and layers 10 to 13 are electrode layers. The green ceramic sheets of the heater and electrode layers are punched, while the green ceramic sheets of the large cavity layer are punched.

[0052] (3) Internal electrode printing: The green ceramic sheets of the heater layer and the electrode layer are printed with internal electrodes according to the pattern requirements. The heater layer is printed with heating electrodes, and the electrode layer is printed with test electrodes.

[0053] (4) Glue spraying / segmented lamination: The raw ceramic sheets of the heater layer, cavity layer, and electrode layer are subjected to glue spraying / lamination operations respectively.

[0054] (5) Warm water isostatic pressing with high pressure: During the operation, the temperature (80°C), preheating (10 min), time (40 MPa / 20 min) and pressure parameters are used to complete the solidification step. The heater layer, cavity layer and electrode layer are solidified to obtain corresponding segmented blocks.

[0055] (6) Spray Glue / Laminating under Pressure: Evenly spray the interface of segmented bar blocks with a mixture of PVB (10%) and absolute ethanol. Use spray glue equipment to evenly spray glue particles with a diameter of (1 to 3 μm) and a density of (60%) on the surface of the bar block segments. Then, according to the laminating sequence of the production plan, use a process with a pressure of (10 t) to laminate for (10 s) at a temperature of (50 °C) for the upper and lower platforms to perform laminating.

[0056] (7) Warm Water Isostatic Pressing with Small Pressure: Then use a warm water isostatic press to preheat at (80 °C) for (10 min), then apply a pressure of (15 MPa), and keep the pressure for (40 min) to further strengthen the interface bonding between the segmented bar blocks to prepare the oxygen sensor chip.

[0057] Example 3:

[0058] As Figure 1 shown, an oxygen sensor chip with an internal reaction cavity. The oxygen sensor chip includes a cavity layer, a heating layer, and an electrode layer. At the same time, the oxygen sensor chip is made by laminating multiple green ceramic sheets. The green ceramic sheets are selected as alumina green ceramic sheets and zirconia green ceramic sheets. The 5th to 8th layers of green ceramic sheets in the middle of the oxygen sensor chip are the cavity layer, the 1st to 4th layers of green ceramic sheets above the cavity layer are the heater layer, and the electrode layer is connected to the lower part of the cavity layer. The oxygen sensor chip is square, with a thickness of 1.0 mm, a single-side length of 50 mm, and a width of 4.5 mm. From top to bottom, there are the heater layer, the cavity layer, and the electrode layer in sequence. The green ceramic sheets of the heater layer and the electrode layer are subjected to punching operations, and the green ceramic sheets of the large cavity layer are subjected to cavity punching operations. The obtained cavity length is 30 mm and the thickness is 0.6 mm. It can achieve that the cavity volume accounts for 60% of the oxygen sensor chip.

[0059] The preparation process of the oxygen sensor chip includes the following steps:

[0060] (1) Provide green ceramic sheets: Prepare 10 alumina green ceramic sheets with a thickness of 185 μm; prepare 1 zirconia green ceramic sheet with a thickness of 185 μm; label the green ceramic sheets in sequence and bake and cure them with parameters of 60 °C / 15 min.

[0061] (2) Punching / Cavity Punching: Distinguish the green ceramic sheets according to the functional layers: the 1st to 3rd layers are the heater layer, the 4th to 8th layers are the cavity layer, and the 9th to 11th layers are the electrode layer; the green ceramic sheets of the heater layer and the electrode layer are subjected to punching operations, and the green ceramic sheets of the large cavity layer are subjected to cavity punching operations.

[0062] (3) Inner Electrode Printing: Perform inner electrode printing operations on the green ceramic sheets of the heater layer and the electrode layer according to the pattern requirements. Print heating electrodes on the heater layer and test electrodes on the electrode layer.

[0063] (4) Glue spraying / segmented lamination: Glue spraying / lamination operations are carried out on the green ceramic sheets of the heater layer, cavity layer, and electrode layer respectively.

[0064] (5) Isostatic pressing with warm water under high pressure for solidification: During the operation, the solidification step is completed using the temperature (80 °C), preheating time (10 min), and pressure parameters (40 MPa / 20 min). The heater layer, cavity layer, and electrode layer are solidified to obtain the corresponding segmented bar blocks.

[0065] (6) Glue spraying / combined pressing lamination: The interface of the segmented bar blocks is evenly sprayed with a mixture of pvb and absolute ethanol with a content of (10%). The surface of the bar block section is evenly sprayed with glue particles with a diameter of (1 to 3 μm) and a density of (60%) using a glue spraying device. Then, according to the combined pressing sequence of the production plan, the lamination and combined pressing are carried out using a process of (10 t) pressure for (10 s), and the heating temperature of the upper and lower platforms is (50 °C).

[0066] (7) Isostatic pressing with warm water under low pressure for combined pressing: After that, the isostatic press with warm water (80 °C) is preheated for (10 min) and then pressurized with a pressure of (15 MPa), and the pressure is maintained for (40 min) to further strengthen the interfacial bonding between the segmented bar blocks to prepare the oxygen sensor chip.

[0067] The oxygen sensor chip with an internal reaction cavity prepared in Example 1 obtains basic data through some simple tests.

[0068] The chip strength test is carried out by using a testing instrument - CTM8020 electronic universal material testing machine and a single-point bending test die. When the pressing rate of the press is 0.75 mm / min, the strength value of the oxygen sensor chip in Example 1 is 350 MPa. The oxygen sensor chip proposed by the present utility model has good mechanical strength, meets the requirements of multi-scene applications, and is more durable.

[0069] The heating performance test is carried out by using an automotive oxygen sensor test system (GLEAD). The test results show that the heating resistance of the oxygen sensor chip in Example 1 at room temperature is 2.2 ± 0.3 Ω; when tested at 9V voltage at room temperature, the steady-state current of the heater in the oxygen sensor chip in Example 1 is 1.55 ± 0.15 A. The heating resistance of the heater in the oxygen sensor chip proposed by the present utility model is small, the energy consumption is small, the heating rate is fast, and the detection efficiency is high.

[0070] The working temperature of the oxygen sensor chip is detected by using an infrared thermal imager. The test results show that the normal working temperature range of the head of the oxygen sensor chip prepared in Example 1 is 700 - 850 °C, and the maximum allowable temperature is 1000 °C. It is ensured that the oxygen sensor chip proposed by the present utility model can work under high-temperature conditions and has good high-temperature resistance performance.

[0071] The above are only the preferred specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily thought of by those who are familiar with the technology within the technical scope disclosed by the present utility model should be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.

Claims

1. An oxygen sensor chip with a built-in reaction cavity, characterized in that The oxygen sensor chip is composed of multiple green ceramic wafers pressed together; Several layers of green ceramic wafers in the oxygen sensor chip are reaction cavity layers, and reaction cavities are provided in the reaction cavity layers; An annular air flow channel communicating with both ends of the reaction cavity is provided on the outer surface of the reaction cavity layer; Several layers of green ceramic wafers above the reaction cavity layer are heater layers, and several layers of green ceramic wafers below are electrode layers; Heating electrodes are provided on the heater layer; test electrodes are provided on the electrode layer.

2. The oxygen sensor chip with a built-in reaction cavity according to claim 1, characterized in that, The depth of the annular air flow channel is 0.01 - 0.05 mm.

3. The oxygen sensor chip with a built-in reaction cavity according to claim 1 or 2, characterized in that, The width of the annular air flow channel is 0.5 - 2.7 mm.

4. The oxygen sensor chip with an internal reaction cavity according to claim 1, characterized in that, The reaction cavity is located in the middle of the reaction cavity layer.

5. The oxygen sensor chip with an internal reaction cavity according to claim 3, characterized in that, The length of the reaction cavity is 24 - 30 mm, and the width is 2.1 - 2.7 mm; The thickness of the reaction cavity is 0.3 - 0.6 mm.

6. The oxygen sensor chip with an internal reaction cavity according to claim 1 or 4, characterized in that, The volume of the reaction cavity accounts for 40% - 60% of the oxygen sensor chip.

7. An oxygen sensor chip with a built-in reaction cavity according to claim 1, characterized in that, The thickness of the oxygen sensor chip is 1.0 - 2.0 mm, the length is 40 - 50 mm, and the width is 3.5 - 4.5 mm.

8. The oxygen sensor chip with an internal reaction cavity according to claim 1, characterized in that, The reaction cavity layer has 3 - 6 layers of green ceramic wafers.

9. The oxygen sensor chip with an internal reaction cavity according to claim 1, characterized in that, The heater layer has 1 - 5 layers of green ceramic wafers; the electrode layer has 2 - 5 layers of green ceramic wafers.

10. The oxygen sensor chip with an internal reaction cavity according to claim 1, characterized in that, Through holes are provided in the heater layer and the electrode layer.

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