A distributed temperature measurement method for a solid oxide fuel cell unit surface

Abstract

The application relates to the technical field of temperature measurement, and discloses a distributed temperature measurement method for the surface of a solid oxide fuel cell unit, which comprises the following steps: preparing a PDC thin film temperature sensor array on the surface of the solid oxide fuel cell, so as to realize distributed measurement of the surface temperature of the solid oxide fuel cell; wherein the PDC thin film temperature sensor array comprises a transition layer, an insulation layer, a sensitive layer, a wire layer, a bonding pad, a protective layer and a lead connection structure; the transition layer is arranged above the cathode, the anode or the electrolyte of the solid oxide fuel cell, the insulation layer covers the top of the transition layer, the sensitive layer, the wire layer and the bonding pad are all arranged above the insulation layer, the sensitive layer comprises an array of multiple temperature sensitive units, the lead connection structure is connected with the wire layer through the bonding pad, and the protective layer covers the top of the sensitive layer and the wire layer. The application can reduce process steps and improve the compatibility of the thin film sensor and the solid oxide fuel cell material.

Description

Technical Field

[0001] This application relates to the field of temperature measurement technology, and in particular to a distributed temperature measurement method for the surface of a solid oxide fuel cell unit. Background Technology

[0002] Solid oxide fuel cells (SOCs) are a promising new energy battery technology with a comprehensive power generation efficiency exceeding 80%. They can be applied in stationary power plants, mobile power generation systems, distributed power plants, new energy vehicles, and new energy ships. They operate without vibration or noise, have high waste heat quality, are environmentally friendly with low carbon emissions, and can use a wide range of fuels. Their operating temperature range is 500–1000°C. SOCs require heating the battery cells to a certain temperature to function properly; excessively high or low temperatures can affect power generation efficiency and even lead to thermal runaway risks. Therefore, temperature measurement of SOCs is crucial.

[0003] Currently, temperature measurement in solid oxide fuel cells mainly uses pin-type K-type thermocouples. However, due to the large size of these thermocouples, the number installed is limited, making distributed temperature measurement impossible. Furthermore, the thermocouple response is slow, and the armored structure of the thermocouple contact with the solid fuel cell surface introduces temperature measurement errors. Thin-film temperature sensors can also be used for surface temperature measurement in solid oxide fuel cells. These sensors offer fast, accurate, and distributed measurement capabilities. The literature [Erdogan, Guk, Vijay, et al. Spring Based Connection of External Wires to a Thin Film Temperature Sensor Integrated Inside a Solid Oxide Fuel Cell.[J]. Scientificreports, 2019.] used a sputtered K-type thin-film thermocouple array for solid oxide fuel cell temperature measurement. This method requires sputtering and two types of thermocouple electrodes, making the process complex. The sputtered alumina, used as an insulating layer, has a significantly different coefficient of thermal expansion from the cathode material, making thermal expansion matching impossible. Polymer-derived ceramics (PDC) are high-temperature resistant materials. The precursor is a liquid, and there are many types available. They are low-cost and easy to deposit into films. Different coatings or thin-film sensors can be prepared by filling different materials with various heat treatment processes. Currently, numerous publications report that PDC has been used to fabricate high-temperature resistant thin-film sensors and coatings. For PDC thin-film sensors, the main principle is: pyrolysis under a protective atmosphere transforms the PDC material into an amorphous semiconductor ceramic, whose resistance decreases with increasing temperature. For coatings, the basic principle is: filling with nano- or micro-powder, heat-treating in air, PDC generates SiO2, while other fillers undergo chemical reactions or remain unchanged, forming a dense thin film. For example, the literature [Yanzhang Fu, Lida Xu, Fuxin Zhao, Chenhe Shao, Yuelong Li, Lanlan Li, Songyue Chen, Qinnan Chen, Lingyun Wang, Daoheng Sun, Chao Wu. Ultrafast high-temperature sintering of polymer-derived ceramic thick filmsensors[J]. Ceramics International, 2024, 50(19, Part B): 36908-36918.] reports a high-temperature resistant thin-film temperature sensor with a temperature resistance of up to 1000℃.The literature [Zaifu Cui, Zhenguo Lu, LiwenHuang, Zitong Xu, Zhonghai Wang, Wenjin Duan, Huayu Che, Bohuai Gou, QiyuLiang, Jiahong Huang, Xiaojun Chen. A ceramic coating from polymer-derived SiCNO for high-temperature electrical insulation on Ni-based alloy substrates[J]. Ceramics International, 2025, 51(7): 9142-9150.] reports a high-temperature resistant insulating coating, and a thin-film thermistor was prepared on it, which measured the temperature up to 900℃. The literature [Chao Wu, Xiaochuan Pan, FanLin, Guochun Chen, Lida Xu, Yingjun Zeng, Yingping He, Daoheng Sun, ZhenyinHai. Al2O3-Modified Polymer-Derived Ceramic SiCN High-Temperature Anti-Oxidative Composite Coating Fabricated by Direct Writing[J]. Polymers, 2022,14(16): 3281.] reports a protective coating with a temperature resistance of 1000℃, which can protect thin-film sensors up to 1000℃. Using PDC materials to fabricate thin-film temperature sensor arrays can reduce process steps and achieve high-precision, fast-response, and distributed temperature measurement on the surface of solid oxide fuel cells.

[0004] In summary, reducing process steps and improving the compatibility of thin-film sensors with solid oxide fuel cell materials are urgent technical problems that need to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a distributed temperature measurement method for the surface of a solid oxide fuel cell unit. A transition layer, an insulating layer, a sensitive layer, a conductive layer, and a protective layer are sequentially fabricated on the electrodes of the solid oxide fuel cell using PDC material. Each layer is patterned and forms a sensing array, which is then connected by leads. The thermal expansion coefficients of the transition layer, the insulating layer, and the sensitive layer are close to those of the insulating layer. This ensures thermal matching between the thin-film sensor and the solid oxide fuel cell material. Insulation performance of the transition layer is not required, but the insulating layer provides electrical isolation between the sensitive film and the conductive lines and the electrodes. The protective layer isolates the sensitive film and the conductive lines from the external environment. Simultaneously, the sensitive film is arranged in an array pattern, thereby enabling the PDC thin-film temperature sensor to reliably measure the temperature distribution on the surface of the solid oxide fuel cell.

[0006] To achieve the above objectives, the following technical solution is adopted:

[0007] This application provides a distributed temperature measurement method for the surface of a solid oxide fuel cell unit, the method comprising:

[0008] A PDC thin-film temperature sensor array is fabricated on the surface of a solid oxide fuel cell to achieve the measurement of the surface temperature distribution of the solid oxide fuel cell; wherein:

[0009] The PDC thin-film temperature sensor array includes a transition layer, an insulating layer, a sensitive layer, a conductive layer, pads, a protective layer, and a lead connection structure. The transition layer is disposed above the cathode, anode, or electrolyte of the solid oxide fuel cell. The insulating layer covers the transition layer. The sensitive layer, conductive layer, and pads are all disposed above the insulating layer. The sensitive layer includes an array of multiple temperature-sensitive units. The lead connection structure is connected to the conductive layer through the pads. The protective layer covers the sensitive layer and the conductive layer.

[0010] Furthermore, the transition layer is made by incorporating 10% to 40% by mass of yttrium-stabilized zirconium oxide or magnesium oxide nanoparticles into the precursor fluid; wherein the precursor fluid is a polysiloxane or a polysilazane.

[0011] Furthermore, the insulating layer is made by incorporating 10% to 40% by mass of boron nitride, silicon nitride, or magnesium oxide nanoparticles into the precursor fluid.

[0012] Furthermore, the sensitive layer is made by incorporating 10% to 40% by mass of titanium diboride, zirconium diboride, or silicon carbide nanoparticles into the precursor fluid.

[0013] Furthermore, the conductive layer is made by incorporating 60%-80% by mass of titanium diboride, zirconium diboride, or silicon carbide nanoparticles into the precursor fluid.

[0014] Furthermore, the protective layer comprises TiB2 nanoparticles and insulating fillers, wherein the insulating fillers are selected from boron nitride, magnesium oxide, or aluminum oxide nanoparticles.

[0015] Furthermore, the lead connection structure includes solder joints formed by platinum wire and PDC material.

[0016] Furthermore, a PDC thin-film temperature sensor array is fabricated on the surface of a solid oxide fuel cell in the following manner;

[0017] PDC slurry containing filler with thermal expansion coefficient adjustment is directly written onto the electrode surface and then pyrolyzed to form a transition layer.

[0018] PDC paste containing insulating filler is directly written onto the transition layer, and then pyrolyzed to form an insulating layer;

[0019] A sensitive layer array, a conductor layer, and pads are patterned on an insulating layer; a direct writing or laser etching process is used to make the linewidth of the sensitive layer 20μm~50μm smaller than that of the insulating layer; the sensitive layer and the conductor layer are then thermally cured.

[0020] A protective layer paste is directly written onto the sensitive layer and the conductive layer, and then pyrolyzed to form a protective layer.

[0021] Connect the lead wire connection structure on the solder pad.

[0022] Furthermore, the lead connection structure is fabricated in the following manner:

[0023] Apply polyimide tape to the alumina flat substrate;

[0024] Place one end of a platinum wire with a diameter of 0.2mm to 0.4mm onto a polyimide tape, and drip the precursor solder paste onto the end of the platinum wire on the polyimide tape. Heat to 900 to 1100℃ and then cool to room temperature. The precursor solder paste will transform into precursor ceramic and detach from the alumina ceramic substrate, and be tightly connected to one end of the platinum wire.

[0025] Remove the oxide layer from the precursor ceramic contact polyimide tape to form a high-temperature lead connection structure with platinum wire and ceramic head.

[0026] Furthermore, the thickness of the transition layer is 5μm~30μm, the thickness of the insulating layer is 5μm~30μm, and the thickness of the sensitive layer, the conductor layer, and the pad is consistent, all being 5μm~30μm.

[0027] This application enables distributed measurement of the surface temperature of solid oxide fuel cell units, and has the following significant technical advantages:

[0028] 1. By employing a transition layer, an insulating layer, and a protective layer, thermal expansion matching of the membrane layers is achieved, improving the reliability of the thin-film sensor. Since solid oxide fuel cells operate at temperatures as high as 500~1000℃, the requirements for thermal expansion matching between the membrane layers in the thin-film sensor are extremely high. If the thermal expansion is mismatched, it may lead to delamination or even membrane detachment, resulting in inaccurate temperature measurement or even sensor failure. This application addresses the issue of the thermal expansion coefficients of the electrodes and electrolytes in solid oxide fuel cells being within (10~12)×10⁻⁶. -6 Between / K, by filling the PDC material with materials such as YSZ and MgO with large coefficients of thermal expansion, the coefficient of thermal expansion of the thin film from the transition layer to the sensitive layer gradually decreases, thereby reducing thermal mismatch.

[0029] 2. Patterning using direct writing or laser removal can achieve fine patterning of the sensing film, reducing its impact on the electrodes of solid oxide fuel cells. Since the electrodes of solid oxide fuel cells have a porous structure, the thin-film sensor fabricated on the electrode should have a small sensor area to avoid affecting the electrochemical reaction and electrical transport of the electrode. Direct writing and laser removal can achieve the fabrication of micro- and nano-sized thin-film linewidths. In this application, the linewidths of the transition layer and insulating layer are in the range of tens to hundreds of micrometers, consistent with the size of the protective layer, while the linewidth of the sensitive layer is slightly smaller, 20–50 μm, thus reducing the impact on the electrochemical reaction of the electrode.

[0030] 3. Thin-film sensor arrays enable accurate, rapid, and distributed temperature measurement. Using direct writing or laser removal to create thin-film sensor arrays allows for multi-point temperature measurement, thus revealing the temperature distribution throughout the solid oxide fuel cell.

[0031] 4. The fabrication process is simple, employing either direct writing or laser removal. The patterning of the transition layer, insulating layer, sensitive layer, conductive layer, and protective layer is achieved using direct writing or laser removal methods, resulting in a relatively simple process. Attached Figure Description

[0032] Figure 1 A schematic diagram of the structure of a PDC thin-film temperature sensor array on a solid oxide fuel cell prepared by a distributed temperature measurement method on the surface of a solid oxide fuel cell unit according to an embodiment of this application is shown.

[0033] Figure 2 An exploded view of the film structure of a PDC thin-film temperature sensor pair on a solid oxide fuel cell prepared by a distributed temperature measurement method on the surface of a solid oxide fuel cell unit according to an embodiment of this application is shown.

[0034] Figure 3 A schematic diagram of the film structure of a PDC thin-film temperature sensor on a solid oxide fuel cell prepared by a distributed temperature measurement method on the surface of a solid oxide fuel cell unit according to an embodiment of this application is shown.

[0035] Figure 4 Optical images of a sensitive thin film, a wire film, and a pad prepared on an alumina substrate according to a distributed temperature measurement method for the surface of a solid oxide fuel cell cell according to an embodiment of this application are shown.

[0036] Figure 5 The diagram illustrates an insulating coating, a PDC sensitive film, wires, and a pad array prepared on the cathode surface of a solid oxide fuel cell unit with a diameter of 50 mm, according to an embodiment of this application for a distributed temperature measurement method on the surface of the solid oxide fuel cell unit.

[0037] Figure 6 The diagram illustrates a distributed temperature measurement method for the surface of a solid oxide fuel cell cell according to an embodiment of this application, showing a schematic diagram of the PDC sensitive film, wires, and pads for fabricating one of the thin-film temperature sensors on the cathode surface of a solid oxide fuel cell cell with a diameter of 50 mm.

[0038] Figure 7 It shows Figure 5 A schematic diagram showing the change in resistance of the intermediate temperature sensor as a function of temperature;

[0039] Figure 8 It shows Figure 5 A schematic diagram showing the changes in resistance and temperature of the intermediate temperature sensor over time.

[0040] Figure 9 It shows Figure 5 A schematic diagram showing the changes in resistance and temperature of the intermediate temperature sensor over time at different temperature ranges. Detailed Implementation

[0041] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0042] The specific implementation methods of this application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0043] Example 1:

[0044] This application provides a distributed temperature measurement method for the surface of a solid oxide fuel cell unit. This method achieves the distributed measurement of the surface temperature of the solid oxide fuel cell by fabricating a PDC thin-film temperature sensor array on the solid oxide fuel cell surface. Figure 1 As shown, the PDC thin-film temperature sensor array includes a transition layer 2, an insulating layer 3, a sensitive layer 4, a conductive layer 5, a pad 6, a solder joint 7, a conductive wire 8, and a protective layer 9. The transition layer 2 is fabricated on the cathode, anode, or electrolyte 1 of the solid oxide fuel cell to create a gradient in the coefficient of thermal expansion, because the coefficient of thermal expansion of the cathode, anode, or electrolyte of the solid oxide battery is relatively large, ranging from (10~13) × 10⁻⁶. -6 / K, while the coefficient of thermal expansion of pure PDC is 3×10. -6 / K, by adding nanofillers, the coefficient of thermal expansion of the transition layer is made slightly smaller than that of the cathode, anode, or electrolyte of a solid oxide fuel cell, but not exceeding 30%. Then, an insulating layer 3 is fabricated on the transition layer 2, and a sensitive layer array 4, a conductive layer 5, and a bonding pad 6 are fabricated on the insulating layer 3. Finally, a protective layer 9 is fabricated on the sensitive layer 4 and the conductive layer 5, and a lead connection structure is fabricated on the bonding pad. The protective layer 9 protects the sensitive layer array 4 and the conductive layer 5 from high-temperature oxidation, and the bonding pad 6 protects the bonding pad from high-temperature oxidation, while simultaneously allowing the high-temperature conductive wires to form an electrical connection with the thin-film conductive wires. Figure 1 The diagram shows a 3×3 array of nine thin-film temperature sensors. The high-temperature leads of the thin-film sensors are connected to an external temperature measurement circuit. When the temperature of the cathode, anode, or electrolyte of the solid oxide battery changes, the resistance of the sensing layer 4 changes. This change is converted into a voltage change by the circuit, and then into a temperature reading, which is displayed. The resistance of the lead layer 9 and the pads 6 is very low and insensitive to temperature changes. Only the resistance of the sensing layer 4 is highly sensitive to temperature changes. The resistance of the sensing layer 4 decreases as the temperature increases, exhibiting a stable functional relationship.

[0045] like Figure 2 The image shown is an exploded view of the membrane structure of a PDC thin-film temperature sensor pair fabricated using the method described in this application for a solid oxide fuel cell. The bottom layer is a transition layer 2, followed by an insulating layer 3. Above the insulating layer 3 are a sensitive thin-film array (sensitive layer 4), a conductive layer 5, and pads 6. Above the sensitive thin-film array and conductive layer 5 is a protective layer 9, and above the pads 6 are solder joints 7. Conductors 8 are electrically connected to the conductive layer 5 via solder joints 7.

[0046] In some embodiments, a method for fabricating a PDC thin-film temperature sensor array on the surface of a solid oxide fuel cell is provided, which is improved in four aspects: 1. By employing a transition layer, an insulating layer, and a protective layer, thermal expansion matching of the film layers is achieved, improving the reliability of the thin-film sensor; 2. By using direct writing or laser removal patterning, fine patterning of the sensing film can be achieved, reducing the impact on the electrodes of the solid oxide fuel cell; 3. The thin-film sensor array can achieve accurate, rapid, and distributed temperature measurement; 4. The fabrication method using direct writing or laser removal is simple.

[0047] Specifically, the method for fabricating a polymer precursor ceramic thin film temperature sensor array on the electrode of a solid oxide fuel cell includes the following steps:

[0048] i. A certain mass fraction of yttria-stabilized zirconia (YSZ) or magnesium oxide nanopowder with a high coefficient of thermal expansion is incorporated into a precursor liquid such as polysiloxane or polysilazane. The mixture is magnetically stirred for more than 1 hour to form a transition layer PDC slurry. The transition layer pattern is then directly written onto the surface of the solid oxide fuel cell cathode using a direct-write printer with a line width of 50μm~100μm. The mixture is then heated to 1000℃ in a low-temperature vacuum environment to pyrolyze the PDC and form a PDC transition layer film.

[0049] ii. A certain mass fraction of nanoparticles with good insulating properties, such as boron nitride, silicon nitride, or magnesium oxide, are incorporated into the precursor liquid such as polysiloxane or polysilazane. The mixture is magnetically stirred for more than 1 hour to form an insulating PDC slurry. The insulating layer pattern is then directly written onto the PDC transition layer film on the surface of the solid oxide fuel cell cathode using a direct-write printer. The line width is consistent with that of the transition layer film. The mixture is then heated to 1000°C in a low-temperature vacuum environment to pyrolyze the PDC and form a PDC insulating layer film.

[0050] iii. A certain mass fraction of conductive nanoparticles such as titanium diboride, zirconium diboride, or silicon carbide are incorporated into a precursor liquid such as polysiloxane or polysilazane. 60%–80% of titanium diboride nanoparticles are incorporated into the precursor liquid of polysiloxane or polysilazane. The mixture is magnetically stirred for more than 1 hour to form PDC slurries for the sensitive layer and thin-film lead layer. The sensitive layer, wires, and pad patterns are directly written onto the PDC insulating film on the surface of the solid oxide fuel cell cathode using a direct-write printer. Alternatively, a layer of slurry can be directly written first, followed by laser removal of the pattern to form the sensitive layer, wire layer, and pads. The sensitive film forms a temperature sensing array, which can be 3×3 or 5×5, depending on the specific requirements. The pad material is the same as the thin-film lead material. The linewidth of the sensitive layer, wire layer, and pads is 20–50 μm smaller than that of the insulating film. The mixture is then heated to 1000°C in a low-temperature vacuum environment to pyrolyze the PDC, forming the PDC sensitive layer, wire layer, and pad film.

[0051] iv. A certain mass fraction of TiB2 nanopowder and nanopowders with good insulation properties, such as BN, MgO, and Al2O3, are incorporated into the precursor liquid of polysiloxane or polysilazane. The mixture is magnetically stirred for more than 1 hour to form a protective PDC slurry. The protective layer pattern is then directly written onto the PDC sensitive layer and lead layer film on the surface of the solid oxide fuel cell cathode using a direct-write printer. The line width is consistent with that of the insulating layer film. Thin-film lead slurry is applied to the pads, and then a PDC connector with platinum wire is pressed onto the slurry on the pads. The mixture is then heated to 1000°C in an atmospheric environment to form the PDC protective layer film and lead connection, thus obtaining the polymer precursor ceramic thin film temperature sensor array on the solid oxide fuel cell.

[0052] Example 2:

[0053] This application provides a distributed temperature measurement method for the surface of a solid oxide fuel cell unit. The method involves fabricating a PDC thin-film temperature sensor array on the surface of the solid oxide fuel cell through the following steps to achieve the distributed measurement of the surface temperature of the solid oxide fuel cell:

[0054] (1) 30% by mass of yttria-stabilized zirconia (YSZ) powder with a particle size of 50 nm was added to the polysilazane precursor liquid and magnetically stirred for 1 hour to form a transition layer PDC slurry. The transition layer pattern was directly written on the cathode surface of the solid oxide fuel cell using a direct-write printer. The line width at the sensitive film was 50 μm, the line width of the conductive layer was 200 μm, and the pad size was 2 mm × 2 mm. The PDC was heated to 1000 °C in a low-temperature vacuum environment to pyrolyze the PDC and form a PDC transition layer film.

[0055] (2) 30% by mass of boron nitride powder with a particle size of 50nm was added to the polysilazane precursor liquid and magnetically stirred for 1 hour to form an insulating layer PDC slurry. The insulating layer pattern was directly written on the PDC transition layer film on the surface of the solid oxide fuel cell cathode using a direct writing printer. The line width was consistent with the transition layer film. The PDC was heated to 1000℃ in a low vacuum environment to pyrolyze the PDC and form a PDC insulating layer film.

[0056] (3) 20% by mass of titanium diboride and 20% by mass of zirconium diboride nanoparticles, both with a particle size of 50 nm, were incorporated into a polysilazane precursor liquid. 70% by mass of titanium diboride nanoparticles were incorporated into a polysilazane precursor liquid. The mixture was magnetically stirred for 1 hour to form PDC slurries for the sensitive layer and thin-film lead layer, respectively. First, a sensitive layer, a conductor layer, and a pad pattern were directly written onto the insulating film. Then, the pattern was removed by laser to form a slightly smaller sensitive layer, conductor layer, and pad. The sensitive film formed a 3×3 temperature sensing array. The pad material was the same as the thin-film lead material. The linewidth of the sensitive layer, conductor layer, and pad was 50 μm smaller than that of the insulating film. The mixture was heated to 1000 °C in a low-temperature vacuum environment to pyrolyze the PDC, forming the PDC sensitive layer, conductor layer, and pad film. Figure 3 Optical images of sensitive films, wire films, and pads prepared on an alumina substrate using a fiber laser are shown. It can be seen that the laser can achieve fine patterning of the sensitive film, and the pattern occupies a very small area, having almost no impact on the electrochemical reaction.

[0057] (4) 30% by mass of TiB2 nanopowder and 20% by mass of BN nanopowder are mixed with precursor liquid such as polysilazane and stirred magnetically for more than 1 hour to form a protective layer PDC slurry. The protective layer pattern is directly written on the PDC sensitive layer and lead layer film on the surface of the solid oxide fuel cell cathode using a direct writing printer. The line width is consistent with the insulating layer film. The thin film lead slurry is applied to the pad, and then the PDC connector with platinum wire is pressed onto the slurry on the pad. It is heated to 1000°C in the atmosphere to form the PDC protective layer film and lead connection. Figure 1 This is a schematic diagram of a 3×3 array of thin-film temperature sensor array fabricated on a solid oxide fuel cell. In reality, the pattern of each layer occupies a smaller electrode area.

[0058] like Figure 3 The diagram shown is a schematic of the membrane structure of the PDC thin-film temperature sensor on a solid oxide fuel cell prepared using the method described in this application. This membrane structure, through the synergistic effect of its layers, achieves high-precision, fast-response, and distributed measurement of the surface temperature of the solid oxide fuel cell, solving problems such as complex processes, thermal expansion mismatch, and inability to perform distributed temperature measurement in existing temperature measurement methods.

[0059] The membrane structure includes, from bottom to top, fuel cell electrode / electrolyte, PDC transition layer, PDC insulation layer, PDC sensitive layer, wire layer, and PDC protective layer.

[0060] Among them, the fuel cell electrode / electrolyte, as the bottom layer, is the core area where the fuel cell carries out electrochemical reactions. Its operating temperature is 500~1000℃, and its coefficient of thermal expansion is relatively large, ranging from (10~13)×10⁻⁶. -6Between / K.

[0061] The PDC transition layer is made of precursor liquids such as polysiloxane or polysilazane, incorporating nanoparticles such as YSZ or magnesium oxide. Its coefficient of thermal expansion is close to that of the fuel cell electrode / electrolyte (slightly smaller but not exceeding 30%), which is used to generate a gradient of the coefficient of thermal expansion, achieve thermal expansion matching of the membrane layer, and avoid delamination or membrane detachment due to thermal mismatch.

[0062] The PDC insulating layer is made by incorporating insulating nanoparticles such as boron nitride, silicon nitride, or magnesium oxide into the precursor liquid. Its linewidth is consistent with that of the transition layer. It is used to achieve electrical isolation between the sensitive film and the wires and the electrodes, ensuring the accuracy of the temperature measurement signal.

[0063] In the PDC sensitive layer and the conductor layer, the sensitive layer is made of a precursor liquid doped with conductive nanoparticles such as titanium diboride, zirconium diboride, or silicon carbide, forming a temperature sensing array (e.g., 3×3, 5×5, etc.). Its resistance decreases with increasing temperature, exhibiting a stable functional relationship, and is used to sense temperature changes. The conductor layer is used to connect the sensitive layer and the pads, and its resistance is not sensitive to temperature changes. The linewidth of both is 20~50μm smaller than that of the insulating layer to reduce the impact on the electrochemical reaction of the electrodes.

[0064] The PDC protective layer is made by incorporating TiB2 nanopowder and insulating nanopowders such as BN, MgO, and Al2O3 into the precursor liquid. The linewidth is consistent with that of the insulating layer. It is used to protect the sensitive layer and the conductor layer from environmental factors such as high-temperature oxidation, thereby improving the reliability and service life of the sensor.

[0065] like Figure 4 The image shown is an optical image schematic of the sensitive thin film, conductive thin film, and pads fabricated on an alumina substrate. The sensitive layer is made of PDC material doped with conductive nanoparticles; its resistance changes with temperature, making it the core of the temperature sensing element, corresponding to the temperature measurement requirements of the fuel cell's operating environment of 500~1000℃. The conductive layer connects the sensitive layer and the pads, transmitting the temperature measurement electrical signal. The insulating layer serves as an insulating substrate, providing insulation support. The pads can serve as interfaces for external testing / circuit connections, enabling signal input and output, and facilitating the acquisition of temperature-resistance change signals from the sensitive layer. This application achieves distributed temperature measurement of the fuel cell surface through an array-type sensitive layer distribution, adapting to high-temperature and complex thermal expansion conditions, and providing accurate data for fuel cell thermal management.

[0066] like Figure 5 The diagram shows an insulating coating, a PDC sensitive film, wires, and a pad array prepared on the cathode surface of a 50mm diameter solid oxide fuel cell unit using the above-described method.

[0067] like Figure 6The diagram shows a schematic of the PDC sensitive film, wires, and pads of one of the thin-film temperature sensors fabricated on the cathode surface of a solid oxide fuel cell unit with a diameter of 50 mm using the above-described method.

[0068] like Figure 7 As shown, Figure 5 The resistance of the intermediate temperature sensor changes with temperature. It can be seen that the three resistance temperature cycles from room temperature to 1000℃ are almost on the same line, so the repeatability is good.

[0069] like Figure 8 As shown, Figure 5 The resistance and temperature of the intermediate temperature sensor change over time. It can be seen that the resistance change rate at 1000℃ is only 2.1%, indicating that the temperature sensor has good high-temperature stability.

[0070] like Figure 9 As shown, Figure 5 The changes in resistance and temperature of the intermediate temperature sensor over time at different temperature ranges show that it exhibits good high-temperature stability in different temperature ranges commonly used in solid oxide fuel cells (600~1000℃).

[0071] In summary, this application employs a direct-write method to fabricate a polymer precursor ceramic thin-film temperature sensor array on the surface of a solid oxide fuel cell, enabling reliable measurement of the surface temperature distribution of the solid oxide fuel cell. By using transition layers, insulating layers, and protective layers, thermal expansion matching, electrical isolation, and isolation from the external environment are achieved, thus ensuring reliable temperature measurement.

[0072] The above embodiments are only used to illustrate this application and are not intended to limit this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application. Therefore, all equivalent technical solutions also fall within the scope of this application, and the patent protection scope of this application should be defined by the claims.

Claims

1. A distributed temperature measurement method for the surface of a solid oxide fuel cell unit, characterized in that, The method includes: A PDC thin-film temperature sensor array is fabricated on the cathode, anode, or electrolyte surface of a solid oxide fuel cell to achieve the measurement of the surface temperature distribution of the solid oxide fuel cell; wherein: The PDC thin-film temperature sensor array includes a transition layer, an insulating layer, a sensitive layer, a conductive layer, pads, a protective layer, and a lead connection structure. The transition layer is disposed above the cathode, anode, or electrolyte of the solid oxide fuel cell. The insulating layer covers the transition layer. The sensitive layer, conductive layer, and pads are all disposed above the insulating layer. The sensitive layer includes an array of multiple temperature-sensitive units. The lead connection structure is connected to the conductive layer through the pads. The protective layer covers the sensitive layer and the conductive layer. The transition layer is made by incorporating 10% to 40% by mass of yttrium-stabilized zirconium oxide or magnesium oxide nanopowder into the precursor fluid; wherein the precursor fluid is polysiloxane or polysilazane. The insulating layer is made by incorporating 10% to 40% by mass of boron nitride, silicon nitride, or magnesium oxide nanopowder into the precursor fluid. The sensitive layer is made by incorporating 10% to 40% by mass of titanium diboride, zirconium diboride, or silicon carbide nanoparticles into the precursor fluid. The conductive layer is made by incorporating 60%-80% by mass of titanium diboride, zirconium diboride, or silicon carbide nanoparticles into the precursor fluid. The protective layer comprises TiB2 nanopowder and insulating filler, wherein the insulating filler is selected from boron nitride, magnesium oxide or aluminum oxide nanopowder.

2. The distributed temperature measurement method according to claim 1, characterized in that, The lead connection structure includes solder joints formed by platinum wire and PDC material.

3. The distributed temperature measurement method according to any one of claims 1 to 2, characterized in that, A PDC thin-film temperature sensor array was fabricated on the surface of a solid oxide fuel cell using the following method; PDC slurry containing filler with thermal expansion coefficient adjustment is directly written onto the electrode surface and then pyrolyzed to form a transition layer. PDC paste containing insulating filler is directly written onto the transition layer, and then pyrolyzed to form an insulating layer; A sensitive layer array, a conductor layer, and pads are patterned on an insulating layer; a direct writing or laser etching process is used to make the linewidth of the sensitive layer 20μm~50μm smaller than that of the insulating layer; the sensitive layer and the conductor layer are then thermally cured. A protective layer paste is directly written onto the sensitive layer and the conductive layer, and then pyrolyzed to form a protective layer. Connect the lead wire connection structure on the solder pad.

4. The distributed temperature measurement method according to claim 3, characterized in that, The lead connection structure is prepared in the following manner: Apply polyimide tape to the alumina flat substrate; Place one end of a platinum wire with a diameter of 0.2mm to 0.4mm onto a polyimide tape, and drip the precursor solder paste onto the end of the platinum wire on the polyimide tape. Heat to 900 to 1100℃ and then cool to room temperature. The precursor solder paste will transform into precursor ceramic and detach from the alumina ceramic substrate, and be tightly connected to one end of the platinum wire. Remove the oxide layer from the precursor ceramic contact polyimide tape to form a high-temperature lead connection structure with platinum wire and ceramic head.

5. The distributed temperature measurement method according to claim 3, characterized in that, The thickness of the transition layer is 5μm~30μm, the thickness of the insulating layer is 5μm~30μm, and the thickness of the sensitive layer, conductor layer and pad is the same, all ranging from 5μm to 30μm.

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