An apparatus and sealing structure for electrochemical testing of fuel cell bipolar plates

Abstract

The application provides a device and sealing structure for electrochemical test of fuel cell bipolar plate, comprising conductive copper rods, end cover plates, copper plates, bipolar plate samples, sealing rings and open end plates arranged in sequence, wherein the sealing ring comprises a sealing base, sealing strips and bosses, the sealing base is provided with a plurality of bosses arranged thereon, and the outermost part of the sealing base is provided with a sealing strip above for sealing the bipolar plate sample. The technical scheme of the application solves the problems of difficulty in sealing the corrosion-resistant test device with the flow channel bipolar plate, high operation difficulty and complex structure in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cells, in particular, especially to a device and sealing structure for electrochemical testing of fuel cell bipolar plates. BACKGROUND

[0002] As one of the main components of fuel cells, bipolar plates are mainly used for conducting current and supporting membrane electrodes. The bipolar plates are in an acidic and high-humidity environment for a long time, and are very prone to corrosion failure. Therefore, it is necessary to evaluate the corrosion resistance of the bipolar plates.

[0003] The evaluation of the corrosion resistance of the bipolar plates mainly uses an electrochemical three-electrode system for detection. In the three-electrode system, the surface to be detected of the bipolar plate is in full contact with an acidic corrosion solution, and a high temperature and an applied potential are applied to simulate the working environment. However, the corrosion electrolytic cell used can seal the smooth plate sample well, but for the bipolar plate sample with a flow channel structure, when using the existing testing device, the corrosion electrolyte will leak along the gap between the flow channel and the sealing ring, which seriously affects the detection experiment. Moreover, the operation is difficult and the structure is complex, so the sealing problem between the bipolar plate sample with a flow channel structure and the solution system needs to be solved urgently. SUMMARY

[0004] In view of the technical problems of difficulty in sealing the bipolar plate with a flow channel and the corrosion resistance testing device, high operation difficulty and complex structure, the present application provides a device and sealing structure for electrochemical testing of fuel cell bipolar plates. The present application mainly uses a sealing ring with a boss and a sealing strip to achieve effective sealing of the bipolar plate sample with a flow channel in the electrochemical corrosion resistance testing system, prevent the corrosion electrolyte from leaking from the flow channel, improve the testing efficiency, and reduce the complexity and operation difficulty of the testing device.

[0005] The technical means adopted by the present application are as follows:

[0006] A sealing structure for electrochemical testing of fuel cell bipolar plates, comprising a sealing ring;

[0007] The sealing ring comprises a sealing base, a sealing strip and a boss, the sealing base is provided with a plurality of bosses, and the outermost part of the sealing base is provided with a sealing strip for sealing the bipolar plate sample.

[0008] Further, the flow channel period of the bipolar plate sample is t1, the flow channel depth is t2, and the flow channel width is t3;

[0009] The height of the sealing base is h1, the width of the sealing base is w1, the sealing strip is a circular ring structure, the height of the sealing strip is h2, the width of the sealing strip is w2, the cross section of the boss is a trapezoidal shape, the upper base width of the trapezoidal shape is w3, and the height of the trapezoidal shape is h3.

[0010] The number of rows of the boss is n, and n is greater than or equal to 3;

[0011] Wherein, h1>3·t2, w2+(n+1)·w3≥w1≥w2+n·w3, h1>h2>t2, w2≤4·t3, w3≤4·t3, h3=h2.

[0012] Further, the upper base of the trapezoidal structure is arc-shaped, used for fitting the flow channel of the bipolar plate sample.

[0013] Further, the boss is provided with a draft angle θ facilitating processing, and the draft angle θ is 2°<θ<10°.

[0014] Further, the material of the sealing ring is fluororubber, silicone rubber or ethylene-propylene-diene rubber, and the hardness is Shore A type.

[0015] A device for electrochemical testing of a fuel cell bipolar plate, comprising a conductive copper rod, an end cover plate, a copper plate, the bipolar plate sample, the sealing ring and an open end plate arranged in sequence.

[0016] The end cover plate is provided with a groove for mounting the copper plate, the conductive copper rod passes through the end cover plate and is connected with the copper plate, the copper plate is closely fitted with the bipolar plate sample, the end cover plate is provided with through holes I for mounting positioning screws around, the open end plate is provided with an opening connected with an electrolytic cell, the opening is in contact with the bipolar plate sample and the opening area is the effective testing area of the bipolar plate sample, the open end plate is provided with through holes II for mounting the positioning screws, the end cover plate and the open end plate are tightly fixed between the positioning screws to realize sealing.

[0017] Further, the conductive copper rod is connected with the copper plate by welding, and the copper plate and the surface of the conductive copper rod are subjected to gold plating treatment.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1. The device and sealing structure for electrochemical testing of a fuel cell bipolar plate provided by the present application realize effective sealing of a bipolar plate sample with a flow channel in an electrochemical corrosion resistance testing system by providing a sealing ring with a boss and a sealing strip, and prevent the corrosion electrolyte from seeping out of the flow channel.

[0020] 2、The application provides a device and sealing structure for electrochemical test of fuel cell bipolar plate, which simplifies the preparation process before test, saves time, improves test efficiency, and improves test accuracy, since the sample of bipolar plate does not need to be sealed before test, and the sealing process before test does not cause error to test result, thus the test result only corresponds to coating failure mechanism, and the reliability of coating failure mechanism analysis is improved.

[0021] 3、The application provides a device and sealing structure for electrochemical test of fuel cell bipolar plate, which avoids complex electrolytic cell structure and is applicable to various types of electrolytic cell, has universality, and can reduce pressure stress during sealing and test operation difficulty under the premise of ensuring good sealing.

[0022] In conclusion, the sealing ring with boss and sealing strip is provided according to the technical scheme of the application, effective sealing of the bipolar plate sample with flow channel in the electrochemical corrosion resistance test system is realized, the corrosive electrolyte is prevented from seeping out of the flow channel, test efficiency is improved, and the complexity and operation difficulty of the test device are reduced. Therefore, the technical scheme of the application solves the problems of sealing difficulty, high operation difficulty and complex structure of the bipolar plate with flow channel and the corrosion resistance test device in the prior art.

[0023] Based on the above reasons, the application can be widely promoted in the field of fuel cells. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 The device structure for electrochemical test of fuel cell bipolar plate is described in the application.

[0026] Figure 2 The sealing ring structure is described in the application.

[0027] Figure 3 The local structure of the sealing ring is described in the application.

[0028] Figure 4 The cross-sectional view of the sealing ring is described in the application.

[0029] Figure 5A comparison chart of the results of potentiostatic polarization of the bipolar plate samples of Example 1 with different sealing methods.

[0030] In the figure: 1, conductive copper pole; 2, end cover plate; 3, positioning screw; 4, bipolar plate sample; 5, sealing ring; 6, open end plate; 7, sealing base; 8, boss; 9, sealing strip. DETAILED DESCRIPTION

[0031] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or their combinations.

[0034] Unless specifically stated otherwise, the relative arrangement of the components and steps, numerical expressions, and numerical values set forth in the various embodiments described herein are not limiting of the scope of the application. Also, it is to be understood that the various equivalents, forms, and modifications are intended to be included within the scope of the application. The examples set forth herein are intended to be illustrative, not limiting. Thus, it will be appreciated that changes can be made to provide different examples with substantially similar functionality. In addition, where a choice of design and / or implementation details are described, equivalent implementations can also be implemented, in some cases without departing from the scope of the application. In other instances, various operations, steps, and / or components are described in terms of two or more separate components or operations which can or can not be physically separate. However, these components and operations can also or instead be provided in a common component or operation which performs the functions of the two or more separate components or operations. As used herein, the term "exemplary" merely means "serving as an example," "demonstrating an example," and the like, and is not intended to indicate that a described example is preferred over other examples. The various exemplary embodiments are described herein in terms of one or more examples, but the examples described herein are not limited to only those examples during the entire description. In addition, where a choice of design and / or implementation details are described, equivalent implementations can also be implemented, in some cases without departing from the scope of the application. In other instances, various operations, steps, and / or components are described in terms of two or more separate components or operations which can or can not be physically separate. However, these components and operations can also or instead be provided in a common component or operation which performs the functions of the two or more separate components or operations. As used herein, the term "exemplary" merely means "serving as an example," "demonstrating an example," and the like, and is not intended to indicate that a described example is preferred over other examples. The various exemplary embodiments are described herein in terms of one or more examples, but the examples described herein are not limited to only those examples during the entire description.

[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0036] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0038] Example 1

[0039] like Figures 2 to 4 As shown, the present invention provides a sealing structure for electrochemical testing of bipolar plates in fuel cells, including a sealing ring 5;

[0040] The sealing ring 5 includes a sealing base 7, a sealing strip 9, and a boss 8. Several bosses 8 are arranged on the sealing base 7. A sealing strip 9 is provided on the outermost part of the sealing base 7 for sealing the bipolar plate sample 4.

[0041] Furthermore, in order to achieve a better sealing effect, there is a dimensional relationship between the bipolar plate sample 4 and the sealing ring 5, the flow channel period of the bipolar plate sample 4 is t1, the flow channel depth is t2, and the flow channel width is t3;

[0042] The height of the sealing base 7 is h1, the width is w1, the sealing strip 9 is a circular ring structure, the height of the sealing strip 9 is h2, the width is w2, the cross section of the boss 8 is a trapezoidal shape, the upper base width of the trapezoid is w3, and the height is h3;

[0043] The number of rows of the boss 8 is n, n≥3;

[0044] Wherein, h1>3·t2, w2+(n+1)·w3≥w1≥w2+n·w3, h1>h2>t2, w2≤4·t3, w3≤4·t3, h3=h2.

[0045] Further, the upper base of the trapezoidal structure is arc-shaped, used to fit the flow channel of the bipolar plate sample 4, and improve the sealing effect.

[0046] Further, the arc-shaped upper base width of the trapezoidal structure is determined by the central angle φ of the arc-shaped upper base, the draft angle θ, and the number of the boss 8 in the same radius, the draft angle θ is 2°<θ<10°, and the draft angle θ is set to facilitate processing.

[0047] Further, the material of the sealing ring 5 is fluororubber, silicone rubber or EPDM, and the hardness is Shore A type.

[0048] As shown in Figure 1 The present application provides a device for electrochemical testing of fuel cell bipolar plates, comprising a conductive copper rod 1, an end cover plate 2, a copper plate, the bipolar plate sample 4, the sealing ring 5 and an open end plate 6 arranged in sequence.

[0049] The end cover plate 2 is provided with a groove for mounting the copper plate, one end of the conductive copper rod 1 passes through the end cover plate 2 and is connected with the copper plate, the other end is connected with the working electrode clamp of the electrochemical workstation, the copper plate is closely attached to the bipolar plate sample 4, through holes I are formed in the periphery of the end cover plate 2 for mounting positioning screws 3, the open end plate 6 is provided with an opening connected with the electrolytic cell, the opening is in contact with the bipolar plate sample 4 and the opening area is the effective testing area of the bipolar plate sample 4, the open end plate 6 is provided with through holes II for mounting the positioning screws 3, and the end cover plate 2 and the open end plate 6 are tightly fixed by the positioning screws 3 to realize sealing.

[0050] Further, the conductive copper rod 1 is connected with the copper plate by welding, and the copper plate and the surface of the conductive copper rod 1 are subjected to gold plating treatment.

[0051] Further, the copper plate is used to collect the current generated when electrochemical corrosion occurs on the bipolar plate sample 4.

[0052] Furthermore, the height h1 of the sealing base 7 is 3 mm and the width w1 is 8 mm;

[0053] The height h2 of the sealing strip 9 is 2 mm and the width w2 is 1 mm;

[0054] The cross-section of the boss 8 is a trapezoidal structure, with the upper base width w3 being 2 mm and the height h3 being 2 mm.

[0055] The draft angle θ is 4°;

[0056] The number of rows n of the bosses 8 is 3;

[0057] The sealing ring 5 is made of silicone rubber with a Shore hardness of 42.

[0058] The bipolar plate sample 4 with a flow channel structure is sealed using the device for electrochemical testing of fuel cell bipolar plates provided by this invention. The device is then connected and secured to the electrolytic cell. A pre-prepared corrosive electrolyte is poured into the electrolytic cell, ensuring that the electrolyte contacts and submerges the effective test surface of the bipolar plate sample 4. The reference electrode and counter electrode are then inserted into the electrolyte. The heating device is turned on to heat the electrolyte. The clamps of the electrochemical workstation are connected to the conductive copper rod 1, the reference electrode, and the counter electrode, respectively. After the electrolyte system temperature reaches the test temperature, a constant potential polarization test is performed on the bipolar plate sample 4 for 5 hours.

[0059] Table 1. Comparison of corrosion current densities of bipolar plate samples with different sealing methods.

[0060]

[0061] Bipolar plate samples that underwent different adhesive sealing treatment times were placed in the same environment as bipolar plate samples sealed with the sealing ring 5 for testing. The experimental results of the potentiostatic polarization curves are as follows: Figure 5 As shown in Table 1, the corrosion current density and current curve fluctuation data are as follows. Analysis shows that the bipolar plate sample that has been sealed with adhesive and left to stand for 1 hour has a higher current density and a larger fluctuation in the current curve. The bipolar plate sample that has been sealed with adhesive and left to stand for 3 hours still has a higher current density, but the fluctuation amplitude of the current curve is significantly reduced. The bipolar plate sample sealed with the sealing ring 5 has a very low corrosion current density and a smooth current curve without fluctuation. This indicates that using the sealing structure and device provided by the present invention can not only improve the accuracy of the test, but also simplify the test procedure, save test time, and improve test efficiency.

[0062] It should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A seal structure for electrochemical testing of fuel cell bipolar plates, characterized by, The sealing ring comprises a sealing base, a sealing strip and a boss, the sealing base is provided with a plurality of bosses, and the outermost side of the sealing base is provided with a sealing strip for sealing the bipolar plate sample. The flow channel period of the bipolar plate sample is t1, the flow channel depth is t2, and the flow channel width is t3. The height of the sealing base is h1, the width is w1, the sealing strip is a circular ring structure, the height of the sealing strip is h2, the width is w2, the cross section of the boss is a trapezoidal shape, the upper base width of the trapezoid is w3, and the height is h3. The number of rows of the boss is n, n≥3. Wherein, h1>3·t2, w2+(n+1)·w3≥w1≥w2+n·w3, h1>h2>t2, w2≤4·t3, w3≤4·t3, h3=h2. The upper base of the trapezoid is arc-shaped, which is used to fit the flow channel of the bipolar plate sample.

2. The seal structure for electrochemical testing of fuel cell bipolar plates of claim 1, wherein, The boss is provided with a draft angle θ for easy processing, and the draft angle θ is 2°<θ<10°.

3. The seal structure for electrochemical testing of fuel cell bipolar plates of claim 1, wherein, The material of the sealing ring is fluororubber, silicone rubber or EPDM, and the hardness is Shore A type.

4. The seal structure for electrochemical testing of fuel cell bipolar plates of claim 1, wherein, The sealing structure for electrochemical testing of fuel cell bipolar plate of claim 1 comprises a conductive copper rod, an end cover plate, a copper plate, the bipolar plate sample, the sealing ring and an open end plate arranged in sequence.

5. An apparatus for electrochemical testing of fuel cell bipolar plates, characterized by, The end cover plate is provided with a groove for mounting the copper plate, the conductive copper rod passes through the end cover plate and is connected with the copper plate, the copper plate is closely attached to the bipolar plate sample, the end cover plate is provided with a through hole I for mounting a positioning screw, the open end plate is provided with an opening connected with an electrolytic cell, the opening is in contact with the bipolar plate sample and the opening area is the effective test area of the bipolar plate sample, the open end plate is provided with a through hole II for mounting the positioning screw, the end cover plate and the open end plate are tightly fixed by the positioning screw, and sealing is realized. The conductive copper rod is connected with the copper plate by welding, and the copper plate and the surface of the conductive copper rod are gold plated.

6. The apparatus for electrochemical testing of fuel cell bipolar plates of claim 5, wherein, ​

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