Fuel Cell Test Fixture

Abstract

This invention discloses a fuel cell test fixture, including an anode battery casing, a cathode battery casing, and a "T"-shaped probe. The cathode battery casing is configured to fit together with the anode battery casing to form a space for accommodating a single cell. The cathode battery casing includes a second flow channel and multiple second channel plates, each with a probe slot. The "T"-shaped probe is used to test the conductivity of the gas diffusion layer on the cathode side of the single cell. The "T"-shaped probe includes a horizontal segment and a vertical segment. The horizontal segment of the "T"-shaped probe is positioned at the probe slot of the second channel plate, and the vertical segment of the "T"-shaped probe passes through the cathode battery casing. In the working state, the "T"-shaped probe corresponds to the truncated area of ​​the single cell, and the horizontal segment of the "T"-shaped probe abuts against the gas diffusion layer on the cathode side of the single cell. In this embodiment of the fuel cell test fixture, the probe slot position corresponds to the truncated gas diffusion layer, ensuring real-time detection and online detection feasibility.

Description

Technical Field

[0001] This invention relates to the field of energy and clean technology, and in particular to a fuel cell test fixture. Background Technology

[0002] The core components of a fuel cell consist of three parts: a proton exchange membrane, a catalyst layer, and a gas diffusion layer. The gas diffusion layer plays a crucial role in supporting the catalyst layer, conducting electricity and heat, and regulating the water-gas balance. Its high cost makes studying its durability essential. During long-term operation of a fuel cell, the gas diffusion layer undergoes both mechanical and chemical degradation. Mechanical degradation includes irreversible mechanical damage caused by compression, freeze-thaw cycles, water dissolution, and airflow erosion. Chemical degradation primarily occurs under certain conditions when carbon reacts with water and is washed away, leading to the collapse of the gas diffusion layer structure. Because the gas diffusion layer has a longer lifespan than other structural components of a fuel cell, simulating its lifespan under normal operating conditions and analyzing its degradation patterns has proven to be a valuable testing method.

[0003] However, research on the aging of the gas diffusion layer has focused on offline accelerated experiments. Offline accelerated experiments simulate the degradation mechanism of the gas diffusion layer, directly applying physical or chemical methods to the gas diffusion body. However, the results of offline accelerated experiments are difficult to correlate with the gas diffusion layer degradation under actual battery operating conditions, and therefore cannot determine the extent to which gas diffusion layer degradation affects battery performance after actual durability testing. Furthermore, some research data shows that there can be significant discrepancies between offline and online durability test results. Currently used online durability tests to quantitatively analyze gas diffusion layer degradation often involve separating the aged gas diffusion layer, reassembling the battery, and conducting performance testing and analysis to determine the contribution of the gas diffusion layer to the overall fuel cell performance degradation.

[0004] The aforementioned so-called "online" testing studies on the impact of gas diffusion layer degradation on battery performance actually focus on performance data after accelerated aging tests or on separating the gas diffusion layer from the disassembled battery. This approach cannot achieve truly real-time, online monitoring of the gas diffusion layer's aging process, and therefore cannot establish a genuine relationship between gas diffusion layer preparation parameters and lifespan. Furthermore, the process of separating the gas diffusion layer from the battery causes varying degrees of physical damage, hindering further aging studies. Therefore, a new fuel cell testing fixture is urgently needed to overcome the limitations of existing testing methods in fully reflecting the aging process of the gas diffusion layer in real time.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a fuel cell testing fixture that can simulate the operating environment of a fuel cell in real time and accurately detect the aging process of the gas diffusion layer.

[0007] To achieve the above objectives, embodiments of the present invention provide a fuel cell test fixture for testing the aging degree of a single cell in a fuel cell. The fuel cell test fixture includes an anode cell housing, a cathode cell housing, and a "T"-shaped probe. The anode cell housing includes a first flow channel groove and a plurality of first groove plates, the first flow channel groove and the plurality of first groove plates together forming a first flow channel. The cathode cell housing is configured to close together with the anode cell housing to form a space for accommodating the single cell. The cathode cell housing includes a second flow channel groove and a plurality of second groove plates, the second flow channel groove and the plurality of second groove plates together forming a second flow channel. The second groove plates have probe grooves. A "T"-shaped probe is used to test the conductivity of the gas diffusion layer on the cathode side of a single cell. The "T"-shaped probe includes a horizontal section and a vertical section fixed to the center of the horizontal section. The horizontal section of the "T"-shaped probe is located at the probe slot of the second slot plate, and the vertical section of the "T"-shaped probe passes through the cathode cell casing. In the working state, the "T"-shaped probe corresponds to the truncated area of ​​the single cell, and the horizontal section of the "T"-shaped probe is used to abut against the gas diffusion layer on the cathode side of the single cell.

[0008] In one or more embodiments of the present invention, the "T"-shaped probe is insulated from the cathode battery casing, the probe groove cuts off the second groove plate, and there is a gap between the "T"-shaped probe and the cut-off second groove plate.

[0009] In one or more embodiments of the present invention, an insulating pad is provided between the transverse section of the "T"-shaped probe and the second flow channel groove.

[0010] In one or more embodiments of the present invention, the cathode battery casing is provided with a circular through hole adapted to the vertical section of the "T"-shaped probe, and the vertical section of the "T"-shaped probe is provided with an insulating sleeve, which passes through and is fixed in the circular through hole.

[0011] In one or more embodiments of the present invention, the “T”-shaped probe has four.

[0012] In one or more embodiments of the present invention, the fuel cell test fixture further includes a conductivity meter, and one end of the "T"-shaped probe is connected to the conductivity meter.

[0013] In one or more embodiments of the present invention, a four-pole double-throw switch connected to the "T"-shaped probe is further included. The four-pole double-throw switch includes a "0" position and a "1" position. The "0" position is connected to the conductivity detector, and the "1" position is connected to the cathode battery casing.

[0014] In one or more embodiments of the present invention, the four-pole double-throw switch switches simultaneously in four positions. When the four-pole double-throw switch is in the "0" position, the conductivity meter is connected to the four "T"-shaped probes. The conductivity meter and the four "T"-shaped probes are insulated from the cathode battery casing and are used to test the conductivity of the gas diffusion layer in the cut-off area of ​​the single cell. When the four-pole double-throw switch is in the "1" position, the four "T"-shaped probes are connected in series with the cathode battery casing and are used to perform normal aging tests on the gas diffusion layer in the cut-off area of ​​the single cell.

[0015] In one or more embodiments of the present invention, the fuel cell test fixture further includes a contact angle detector, the contact angle detector including a syringe, a syringe needle and a fixing component disposed on the syringe, the fixing component including a fixing screw, a sealing sleeve and a locking nut, the cathode battery housing is provided with a threaded hole, the bottom surface of the threaded hole is provided with a central through hole, the central through hole is used to insert the syringe needle, and the threaded hole is used to cooperate with the fixing component to seal the fuel cell test fixture.

[0016] In one or more embodiments of the present invention, observation slots communicating with the second flow channel are provided on both sides of the second flow channel, the observation slots are provided with quartz window plates, and fixed steel plates are provided on both sides of the cathode battery case, each of the fixed steel plates being provided with an observation window.

[0017] Compared with existing technologies, the fuel cell test fixture of this embodiment features a probe slot on the second slot plate, which perfectly integrates the probe with the flow channel of the battery casing. The position of the probe slot corresponds to the truncated gas diffusion layer, making the test environment of the truncated gas diffusion layer basically consistent with that of the overall gas diffusion layer, ensuring real-time detection and online detection feasibility. By designing a four-pole double-throw switch to test the conductivity of the gas diffusion layer, normal aging tests can also be performed on the gas diffusion layer. By setting a fixing component on the structure of the existing contact angle tester, and setting a threaded hole on the cathode battery casing to cooperate with the fixing component, a central through hole and an observation window are set to detect the contact angle of the gas diffusion layer, and the aging process of the gas diffusion layer can be analyzed in conjunction with the conductivity. This invention can be improved based on existing fuel cell test fixtures, is easier to operate, saves resources, and does not require the additional preparation of new test fixtures. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the cathode battery shell structure and the "T"-shaped probe structure according to one embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Enlarged view of the structure at point A in the middle;

[0020] Figure 3 This is a schematic diagram of the second flow channel structure according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of a single-cell structure according to an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the anode battery casing structure according to an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the overall structure of the cathode battery casing according to an embodiment of the present invention;

[0024] Figure 7 yes Figure 6 Enlarged view of the structure at point C;

[0025] Figure 8 This is a schematic diagram showing the connection relationship between the conductivity meter, the four-pole double-throw switch and the cathode battery casing according to one embodiment of the present invention.

[0026] Figure 9 This is a schematic diagram of the overall structure of a fuel cell clamp according to an embodiment of the present invention;

[0027] Figure 10 This is a schematic diagram of the cathode battery casing according to another embodiment of the present invention;

[0028] Figure 11 yes Figure 10 Exploded view of the structure at point D;

[0029] Figure 12 This is a schematic diagram of the cathode battery casing structure according to another embodiment of the present invention;

[0030] Figure 13 This is a schematic diagram of the observation window according to an embodiment of the present invention;

[0031] Figure 14 This is a schematic diagram of the droplet observation principle according to one embodiment of the present invention;

[0032] Explanation of key figure labels:

[0033] 1-Anode battery casing, 11-First flow channel groove, 12-First groove plate, 13-First flow channel,

[0034] 2-Cathode cell housing, 21-Second flow channel groove, 22-Second groove plate, 221-Probe groove, 23-Second flow channel, 24-Circular through hole, 25-Threaded hole, 26-Central through hole, 27-Observation groove, 271-Quartz window plate, 28-Fixing steel plate, 281-Observation window.

[0035] 3- "T" shaped probe, 31- Horizontal segment, 32- Vertical segment, 33- Insulating sleeve.

[0036] 4-Conductivity meter, 5-Four-pole double-throw switch, 61-Injector, 62-Injector needle, 63-Fixing assembly, 631-Fixing screw, 632-Sealing sleeve, 633-Locking nut, 7-Droplet, 8-Single cell. Detailed Implementation

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0038] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0039] Most studies on the lifespan of gas diffusion layers focus on offline accelerated aging, which differs significantly from the actual battery operating environment, making it difficult to establish an accurate gas diffusion layer lifespan evaluation mechanism. The aging performance degradation of the gas diffusion layer is mainly reflected in two aspects: a decrease in the elastic modulus, leading to reduced pressure resistance, increased contact resistance, increased ohmic polarization of the fuel cell, and reduced battery performance; and a decrease in the hydrophobicity, reducing water management capabilities, hindering the transport of reactant gases, increasing diffusion polarization, and reducing battery performance. The elastic modulus of the gas diffusion layer is primarily based on conductivity test data, while the hydrophobicity is primarily based on contact angle test data. This invention uses these two types of data to perform real-time, online analysis of the aging process of the gas diffusion layer. After connecting to an external fuel cell test platform, based on different conditions of gas diffusion layer degradation such as compression, freeze-thaw cycles, water dissolution, airflow erosion, start-up and shutdown, and variable loads, the changes in the contact angle and conductivity of the gas diffusion layer under different accelerated degradation conditions and operating conditions are specifically monitored online, relating to battery performance and gas diffusion layer lifespan. This allows for the identification of preparation parameters that need improvement from the perspective of gas diffusion layer fabrication.

[0040] like Figures 1 to 14As shown, a fuel cell test fixture according to a preferred embodiment of the present invention includes an anode battery housing 1, a cathode battery housing 2, and a "T"-shaped probe 3. This fuel cell test fixture is used to test the aging degree of a single cell in a fuel cell. The anode battery housing 1 includes a first flow channel 11 and a plurality of first channel plates 12, which together form a first flow channel 13. The cathode battery housing 2 is configured to cover the anode battery housing 1, forming a space for accommodating a single cell 8. The cathode battery housing 2 includes a second flow channel 21 and a plurality of second channel plates 22, which together form a second flow channel 23. Probe slots 221 are provided on the second channel plates 22. The "T"-shaped probe 3 is used to test the conductivity of the gas diffusion layer on the cathode side of the single cell 8. The "T"-shaped probe 3 includes a horizontal segment 31 and a vertical segment 32 fixed to the center of the horizontal segment 31. The horizontal segment 31 of the "T"-shaped probe 3 is disposed at the probe groove 221 of the second groove plate 22, and the vertical segment 32 of the "T"-shaped probe 3 passes through the cathode cell housing 2. In the working state, the horizontal segment 31 of the "T"-shaped probe 3 corresponds to the truncated area of ​​the single cell 8, and the horizontal segment 31 of the "T"-shaped probe 3 is used to abut against the gas diffusion layer on the cathode side of the single cell 8.

[0041] In this embodiment of the fuel cell test fixture, a probe slot 221 is provided on the second slot plate 22. The probe is shaped like a "T" and is perfectly integrated with the second flow channel 23 of the cathode cell housing 2. The position of the probe slot 221 corresponds to the truncated gas diffusion layer, ensuring that the test environment of the truncated gas diffusion layer is basically consistent with that of the overall gas diffusion layer, thus guaranteeing the real-time nature of the detection and the feasibility of online detection. This invention can be improved based on existing fuel cell test fixtures without the need for additional fabrication of new test fixtures, saving resources and simplifying the testing operation.

[0042] like Figure 1 , Figure 3 and Figure 4 As shown, Figure 4 In the diagram, region B represents the truncated gas diffusion layer. When testing conductivity using the fuel cell test fixture, a single cell 8 is placed within the fixture. The single cell 8 includes a membrane electrode assembly (MEA) and gas diffusion layers on both sides of the MEA. A truncated region B is located on the gas diffusion layer on the cathode side. This truncated region B corresponds to the position of the "T"-shaped probe 3. The transverse segment 31 of the "T"-shaped probe 3 can abut against the truncated gas diffusion layer, thereby testing the conductivity of the gas diffusion layer on the cathode side.

[0043] For testing the conductivity of the gas diffusion layer, insulation between the "T"-shaped probe 3 and the cathode cell housing 2 must be ensured. Specifically, the probe groove 221 cuts off the second groove plate 22, and there is a gap between the transverse section 31 of the "T"-shaped probe 3 and the cut-off second groove plate 22. In some embodiments, an insulating pad (not shown in the figure) is provided between the transverse section 31 of the "T"-shaped probe 3 and the second flow channel groove 21 to ensure the insulation effect between the transverse section 31 of the "T"-shaped probe 3 and the cathode cell housing 2.

[0044] like Figure 1 As shown, in some embodiments, the cathode battery housing 2 has a circular through hole 24 adapted to the vertical section 32 of the "T"-shaped probe 3. An insulating sleeve 33 is provided on the vertical section 32 of the "T"-shaped probe 3, passing through and fixed at the circular through hole 24. By providing a gap between the horizontal section 31 and the truncated second groove plate 22, providing an insulating pad between the horizontal section 31 and the second flow channel groove 21, and filling the gap between the vertical section 32 and the circular through hole 24 with an insulating sleeve, the "T"-shaped probe and the cathode battery housing 2 are kept completely insulated.

[0045] like Figure 1 , Figure 3 and Figure 8 As shown, conductivity can generally be tested using a conductivity meter 4. A four-probe conductivity meter is a commonly used device. Correspondingly, four "T"-shaped probes 3 also need to be set up.

[0046] Specifically, such as Figure 8 As shown, to ensure sufficient test data, a four-pole double-throw switch 5 is installed between the conductivity meter 4 and the "T"-shaped probe 3. The four-pole double-throw switch 5 has two positions: "0" and "1". One end of the four-pole double-throw switch 5 is connected to the four "T"-shaped probes 3, the "0" position of the four-pole double-throw switch 5 is connected to the conductivity meter 4, and the "1" position of the four-pole double-throw switch 5 is connected to the cathode battery casing 2.

[0047] Considering the ease of switching, the four-pole double-throw switch allows for simultaneous switching of four poles. For example... Figure 8 As shown, when the four-pole double-throw switch 5 is in the "0" position, the conductivity meter 4 is connected to the four "T"-shaped probes 3. Both the conductivity meter 4 and the four "T"-shaped probes 3 are insulated from the cathode battery casing 2. The conductivity meter 4 is used to test the conductivity of the gas diffusion layer in the truncated area of ​​the single cell 8. When the four-pole double-throw switch 5 is in the "1" position, the four "T"-shaped probes 3 are connected in series with the cathode battery casing 2 and are used to perform normal aging tests on the gas diffusion layer in the truncated area of ​​the single cell 8. The truncated gas diffusion layer is the gas diffusion layer on the cathode side.

[0048] like Figure 1 , Figure 7 , Figure 9 , Figure 10 and Figure 11 As shown, in one embodiment, four probes 221 are formed by cutting off 13.4 mm from the four second slot plates 22 connected to the cathode battery casing 2. Each probe slot 221 has a through circular hole 24 in the center, and the bottom diameter of each circular hole 24 is 2 mm. The vertical segment 32 of the "T"-shaped probe 3 has dimensions of 1 mm × 1 mm × 27.5 mm, the horizontal segment 31 has a length of 13 mm, the width of the horizontal segment 31 is the same as the width of the second slot plate 22 (1 mm), and the height is 0.85 mm. The distance between the horizontal segment 31 of the "T"-shaped probe 3 and the cut second slot plate 22 is 0.2 mm for insulation. An insulating pad with a thickness of 0.15 mm is provided between the horizontal segment 31 and the cathode battery casing 2. The vertical segment 32 is covered with an insulating sleeve 33 on the outside and is fully fixed in the circular hole 24 to achieve insulation between the "T"-shaped probe 3 and the cathode battery casing 2.

[0049] like Figure 6 As shown, the ingenuity of this design lies in the perfect integration of the "T"-shaped probe 3 with the second flow channel 23 of the cathode battery shell 2. When testing the conductivity of the gas diffusion layer on the cathode side, the tested gas diffusion layer area is basically consistent with the test environment of the entire aged gas diffusion layer, ensuring the real-time performance and accuracy of online detection.

[0050] Secondly, the contact angle of the gas diffusion layer is measured. For example... Figure 10 As shown, in some embodiments, the fuel cell test fixture also includes a contact angle detector. During contact angle testing, the cathode battery casing 2 needs to be drilled and sealed. Specifically, the contact angle detector includes a syringe 61, a syringe needle 62, and a fixing component 63 mounted on the syringe 61. The fixing component 63 includes a fixing screw 631, a sealing sleeve 632, and a locking nut 633, wherein the locking nut 633 is a pressure-locking nut for the sealing sleeve. The cathode battery casing 2 has a threaded hole 25. In one embodiment, the threaded hole 25 is M6 in size and 10mm deep. The threaded hole 25 is not through-hole, and a 1mm diameter central through-hole 27 is provided on the bottom surface of the threaded hole 25. The central through-hole 27 is used to insert the syringe needle 62 of the contact angle detector into the battery casing to drip droplets 7 onto the gas diffusion layer on the cathode side. The diameter of the syringe needle 62 is 0.5mm. When the pressure-locking nut for the sealing sleeve is tightened, the syringe needle 62 is fixed and locked, simultaneously providing a seal.

[0051] like Figure 6 , Figure 12As shown, to facilitate the detection of the contact angle of the droplet 7, observation slots 27 are provided on both sides of the second flow channel of the cathode battery casing, and the observation slots 27 are connected to the second flow channel 23. A quartz window 271, matching the size of the observation slot 27, is provided inside the observation slot 27. In this embodiment, by providing the quartz window 271 to open the optical path, it is convenient for the light source and camera of the contact angle detector to image the droplet and collect data. Besides the quartz window 271, other optical components with excellent light transmission can also be used. Specifically, Figure 12 In the middle, the direction of the dashed line is the direction of the light path.

[0052] In one embodiment, the quartz window 271 has dimensions of 23mm × 7mm × 11mm. The two 7mm × 11mm planes (i.e., the planes through which the light path passes) are mirror-like and translucent, while the remaining surfaces are frosted to facilitate adhesion of the adhesive to the entire battery casing. After the quartz window 271 is bonded with sealant, a fixing steel plate 28 is provided on the outside to seal the quartz window 271.

[0053] For ease of observation, an observation window 281 is provided on the fixed steel plate 28. Specifically, as shown... Figure 13 The image shown is a schematic diagram of the observation window, simulating the imaging of a 1μL droplet injected by the contact angle tester syringe. The maximum diameter of the 1μL droplet is 1.3mm, which is smaller than the width of the second flow channel 23 (3mm). Figure 14 As shown, the light source and camera of the contact angle detector are respectively set at the observation windows 281 on both sides, with the light source on the left and the camera on the right.

[0054] Compared to typical single-cell tests, which output the polarization curve, CV curve, impedance, current, voltage, and power of the entire membrane electrode, this embodiment, in addition to the above data, can also output the contact angle and conductivity of the cathode gas diffusion layer.

[0055] Through the above technical solutions, a common fuel cell fixture has been successfully combined with four-probe conductivity testing and contact angle testing functions, enabling real-time, online output of conductivity and contact angle data during the accelerated aging process of the gas diffusion layer under test.

[0056] Compared to the offline accelerated aging methods used in most gas diffusion layer aging studies, this invention employs online accelerated aging research to realistically simulate the aging of the gas diffusion layer under fuel cell operating conditions. This allows for a correlation between the gas diffusion layer degradation under actual battery operating conditions and the actual impact of gas diffusion layer degradation on battery performance after durability testing. This enables a deeper understanding and improvement of the gas diffusion layer's durability, and establishes an accurate evaluation of the gas diffusion layer's durability.

[0057] Compared to most online aging studies of gas diffusion layers, this method can output the two main performance parameters of the gas diffusion layer—contact angle and conductivity—at any point in the accelerated aging process, without interrupting the test or disassembling the battery to isolate the gas diffusion layer for study. This allows for truly real-time, online monitoring of the aging process of the gas diffusion layer and establishes a genuine relationship between the gas diffusion layer preparation parameters and its lifetime.

[0058] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A fuel cell test fixture for testing the aging degree of the gas diffusion layer of a single cell in a fuel cell, characterized in that, The fuel cell test fixture includes: The anode battery casing includes a first flow channel groove and a plurality of first groove plates, wherein the first flow channel groove and the plurality of first groove plates together form a first flow channel; A cathode battery housing is configured to fit together with the anode battery housing to form a space for accommodating the single cell. The cathode battery housing includes a second flow channel groove and a plurality of second groove plates, the second flow channel groove and the plurality of second groove plates forming a second flow channel. The second groove plates have probe grooves. A "T"-shaped probe is used to test the conductivity of the gas diffusion layer on one side of the cathode of a single cell. The "T"-shaped probe includes a horizontal section and a vertical section fixed to the center of the horizontal section. The horizontal section of the "T"-shaped probe is located at the probe slot of the second slot plate, and the vertical section of the "T"-shaped probe passes through the cathode cell shell. In the working state, the "T"-shaped probe corresponds to the truncated area of ​​the single cell, and the horizontal segment of the "T"-shaped probe is used to abut against the gas diffusion layer on the cathode side of the single cell.

2. The fuel cell test fixture as described in claim 1, characterized in that, The "T"-shaped probe is insulated from the cathode battery casing, the probe groove cuts off the second groove plate, and there is a gap between the "T"-shaped probe and the cut-off second groove plate.

3. The fuel cell test fixture as described in claim 2, characterized in that, An insulating pad is provided between the horizontal section of the "T"-shaped probe and the second flow channel groove.

4. The fuel cell test fixture as described in claim 1, characterized in that, The cathode battery casing is provided with a circular through hole that matches the vertical section of the "T"-shaped probe. The vertical section of the "T"-shaped probe is provided with an insulating sleeve, which is inserted and fixed in the circular through hole.

5. The fuel cell test fixture as described in claim 1, characterized in that, There are four "T"-shaped probes.

6. The fuel cell test fixture as described in claim 5, characterized in that, It also includes a conductivity meter, one end of which is connected to the conductivity meter.

7. The fuel cell test fixture as described in claim 6, characterized in that, It also includes a four-pole double-throw switch connected to the "T"-shaped probe. The four-pole double-throw switch includes a "0" position and a "1" position. The "0" position is connected to the conductivity detector, and the "1" position is connected to the cathode battery casing.

8. The fuel cell test fixture as described in claim 7, characterized in that, The four-pole double-throw switch switches simultaneously in four positions. When the four-pole double-throw switch is in the "0" position, the conductivity meter is connected to the four "T"-shaped probes. The conductivity meter and the four "T"-shaped probes are insulated from the cathode battery casing and are used to test the conductivity of the gas diffusion layer in the cut-off area of ​​the single cell. When the four-pole double-throw switch is in the "1" position, the four "T"-shaped probes are connected in series with the cathode battery casing and are used to perform normal aging tests on the gas diffusion layer in the cut-off area of ​​the single cell.

9. The fuel cell test fixture as described in claim 1, characterized in that, It also includes a contact angle detector, which includes a syringe, a syringe needle, and a fixing component disposed on the syringe. The fixing component includes a fixing screw, a sealing sleeve, and a locking nut. The cathode battery housing is provided with a threaded hole, and a central through hole is provided at the center of the bottom surface of the threaded hole. The central through hole is used to insert the syringe needle, and the threaded hole is used to cooperate with the fixing component to seal the fuel cell test fixture.

10. The fuel cell test fixture as described in claim 9, characterized in that, The second flow channel is provided with observation slots on both sides, which are connected to the second flow channel. Each observation slot is provided with a quartz window plate. The cathode battery shell is provided with fixed steel plates on both sides, and each fixed steel plate is provided with an observation window.

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