Bonding method of bipolar plate and membrane electrode assembly and proton exchange membrane fuel cell

Abstract

The invention relates to the technical field, in particular to a bonding method of a bipolar plate and a membrane electrode assembly and a proton exchange membrane fuel cell. The bipolar plate provided with a plurality of glue line grooves and a plurality of first through holes is bonded with the membrane electrode assembly comprising a membrane electrode body and a frame; the method specifically comprises the steps that the bipolar plate with the upper surface coated with glue and a membrane electrode assembly sequentially penetrate through a mounting piece to be attached to a first mold, the upper surface of the bipolar plate is attached to the lower surface of the membrane electrode assembly, and three edges of the bipolar plate and three edges of the membrane electrode assembly are fixed through positioning pieces; the second mold is attached to the membrane electrode assembly to obtain a bonding unit, the bonding unit is put into a hot pressing device to be subjected to hot pressing, and after hot pressing is completed, the first mold and the second mold are removed to obtain the bipolar plate and the membrane electrode assembly which are firmly bonded; according to the method, tight bonding of the bipolar plate and the membrane electrode assembly can be achieved, the bipolar plate and the membrane electrode assembly cannot deviate in the bonding and transporting process, and internal gas and liquid can be effectively prevented from leaking.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a method for bonding a bipolar plate and a membrane electrode assembly and a proton exchange membrane fuel cell. Background Art

[0002] Proton exchange membrane fuel cell is a clean energy technology that converts hydrogen and oxygen directly into electricity and water through electrochemical reactions. It has the advantages of high energy conversion efficiency, environmental friendliness, fast start-up speed, low operating temperature and low noise. It is widely used in transportation, fixed power supply and portable power supply.

[0003] The proton exchange membrane fuel cell consists of an end plate, a membrane electrode assembly and a bipolar plate. The specific steps are as follows: First, place an end plate flat on the assembly platform, place the bipolar plate on the end plate, and ensure that it accurately matches the positioning structure of the end plate. Then place the prepared membrane electrode assembly on the bipolar plate, aligning the anode side of the membrane electrode assembly with the anode bipolar plate, and the cathode side with the cathode bipolar plate. According to the above method, stack the bipolar plates and membrane electrode assemblies in sequence. After all the bipolar plates and membrane electrodes are stacked, place another end plate on the top, also align it accurately with the components below, and perform preliminary positioning. Finally, use a special fixture or press to apply uniform pressure to the assembled battery stack so that the components fit tightly together. While applying pressure, use bolts, nuts, straps or welding to firmly fix the two end plates together to keep the entire battery stack in a stable structure.

[0004] During the above assembly process, the membrane electrode assembly and the bipolar plate are prone to offset during stacking and assembly due to inaccurate positioning, resulting in internal gas and liquid leakage. In addition, the membrane electrode assembly and the bipolar plate of the proton exchange membrane fuel cell assembled by the above preparation method are also prone to offset during transportation, affecting the performance of the fuel cell. Therefore, it is considered to closely adhere the membrane electrode assembly to one side of the bipolar plate and then repeatedly stack them to reduce the risk of offset between the membrane electrode assembly and the bipolar plate. Summary of the invention

[0005] The purpose of the present application is to provide a method for bonding a bipolar plate and a membrane electrode assembly and a proton exchange membrane fuel cell, in which the membrane electrode assembly is tightly adhered to a single side of the bipolar plate to reduce the deviation of the bipolar plate and the membrane electrode assembly during assembly and transportation.

[0006] To achieve the above-mentioned purpose, the present application adopts a bonding method of a bipolar plate and a membrane electrode assembly, wherein a plurality of glue line grooves and a plurality of first through holes are provided on the bipolar plate, the plurality of glue line grooves are respectively provided along the circumference of the upper surface and the lower surface of the bipolar plate, the plurality of first through holes are symmetrically provided at both ends of the bipolar plate, the membrane electrode assembly comprises a membrane electrode body and a frame, the frame is fixedly connected to the outer periphery of the membrane electrode body, the two ends of the frame are respectively provided with second through holes corresponding to the first through holes, the upper surface of the frame is provided with a sealing glue line corresponding to the glue line groove on the lower surface, comprising:

[0007] Placing a first mold on a workbench, wherein the first mold comprises a plate body, a positioning member and a mounting member, wherein the plate body is provided with a plurality of positioning grooves and a plurality of first mounting grooves, wherein the positioning member is inserted into the positioning grooves for positioning the three sides of the bipolar plate, wherein the first mounting grooves correspond to the first through holes and the second through holes one by one, and wherein the mounting member is inserted into the first mounting grooves;

[0008] Apply glue in the glue line groove on the upper surface of the bipolar plate, and place the lower surface of the bipolar plate after glue application in contact with the upper surface of the first mold, with the mounting member passing through the first through hole;

[0009] Placing the lower surface of the membrane electrode assembly in contact with the upper surface of the bipolar plate, and passing the mounting member through the second through hole;

[0010] The lower surface of the second mold is placed in contact with the upper surface of the membrane electrode assembly to obtain a bonding unit, the second mold is provided with a groove and a plurality of second mounting holes, the groove is provided on the lower surface of the second mold, the second mounting holes are provided on both sides of the second mold, the groove is consistent with the shape of the glue line groove on the bipolar plate, the groove is engaged with the sealing glue line, and the mounting piece passes through the first through hole, the second through hole and the second mounting groove in sequence;

[0011] The bonding unit is placed in a hot pressing device, and the heating temperature and heating time are set for hot pressing. After the hot pressing is completed, the first and second molds are removed in sequence to obtain a bonded bipolar plate and membrane electrode assembly.

[0012] As a preferred technical solution, the mounting member includes a first boss and a second boss, the cross-sectional area of ​​the first boss is smaller than that of the second boss, the first boss is used to engage with the first mounting groove, and the second boss is used to engage with the second mounting groove.

[0013] As a preferred technical solution, the glue is epoxy glue.

[0014] As a preferred technical solution, the hot pressing device is a hot press.

[0015] As a preferred technical solution, the heating temperature is 90-120° C., and the heating time is 2-5 min.

[0016] The present application also provides another method for bonding a bipolar plate to a membrane electrode assembly, which uses the first mold, the second mold, the bipolar plate and the membrane electrode assembly in the above-mentioned method for bonding a bipolar plate to a membrane electrode assembly, and specifically includes:

[0017] Placing the first mold on a workbench, and inserting the positioning member and the mounting member into the positioning groove and the first mounting groove respectively;

[0018] Apply glue in the glue line groove on the upper surface of the bipolar plate, and place the lower surface of the bipolar plate after glue application in contact with the upper surface of the first mold, with the mounting member passing through the first through hole;

[0019] Placing the lower surface of the membrane electrode assembly in contact with the upper surface of the bipolar plate, and passing the mounting member through the second through hole;

[0020] The lower surface of the second mold is placed on the upper surface of the membrane electrode assembly to obtain a bonding unit, the groove is engaged with the sealing glue line, and the mounting member passes through the first through hole, the second through hole and the second mounting groove in sequence;

[0021] The bonding unit is placed in a curing device, and the curing time and curing power are set for hot pressing. After the curing is completed, the first and second molds are removed in sequence to obtain a bonded bipolar plate and membrane electrode assembly.

[0022] As a preferred technical solution, the glue is shadowless glue.

[0023] As a preferred technical solution, the curing device is a UV curing oven.

[0024] As a preferred technical solution, the curing time is 45 to 60 seconds and the curing power is 450 to 550 mW / cm 2 .

[0025] The present application also provides a proton exchange membrane fuel cell, comprising a plurality of bipolar plates and a plurality of membrane electrode assemblies, wherein the plurality of bipolar plates and the plurality of membrane electrode assemblies are sequentially bonded by the above-mentioned bonding method of bipolar plates and membrane electrode assemblies.

[0026] A method for bonding a bipolar plate and a membrane electrode assembly in the present application is to make a first mold and a second mold, wherein the first mold includes, and the second mold is provided with, the lower surface of the bipolar plate is placed on the first mold, and multiple positioning members are used to position the three sides of the bipolar plate, the membrane electrode assembly is placed on the upper surface of the bipolar plate coated with glue, and then the second mold is placed on the membrane electrode assembly to obtain a bonding unit, wherein the mounting member is inserted into the first mounting groove, and sequentially passes through the first through hole, the second through hole and the second mounting groove to engage. Then, the bonding unit is placed in a hot pressing device, and a suitable heating temperature and heating time are set to perform hot pressing on it. After the hot pressing is completed, the first and second molds are removed to obtain a firmly bonded bipolar plate and membrane electrode assembly. In the above process, the membrane electrode assembly and the bipolar plate will not be offset during the bonding process, and the internal gas and liquid will not leak, which effectively reduces the risk of offset between the membrane electrode assembly and the bipolar plate; the two are firmly bonded, which is conducive to safe transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present application is further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present application. In addition, unless otherwise specified, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

[0028] Figure 1 is a schematic diagram of a bipolar plate of the present invention;

[0029] Figure 2 is a schematic diagram of a membrane electrode assembly of the present invention;

[0030] Figure 3 is a schematic diagram of a bonding unit of the present invention;

[0031] Figure 4 is a schematic diagram of a mounting member of the present invention;

[0032] Figure 5 is a schematic diagram of a second mold of the present invention;

[0033] Among them: 1. first mold; 11. positioning groove; 12. mounting piece; 121. first boss; 122. second boss; 13. first mounting groove; 14. positioning piece; 2. bipolar plate; 21. glue line groove; 22. upper surface; 23. lower surface; 24. first through hole; 3. membrane electrode assembly; 31. membrane electrode body; 32. frame; 321. sealing glue line; 33. second through hole; 4. second mold; 41. groove; 42. second mounting groove. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of the present application, it should be understood that the terms "front", "rear", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0036] See also Figure 3-5 , a bonding method for a bipolar plate 2 and a membrane electrode assembly 3 provided in an embodiment of the present application, wherein a plurality of glue grooves 21 and a plurality of first through holes 24 are provided on the bipolar plate 2, wherein the plurality of glue grooves 21 are respectively provided along the circumference of the upper surface 22 and the lower surface 23 of the bipolar plate 2, and the plurality of first through holes 24 are symmetrically arranged at the two ends of the bipolar plate 2, and the membrane electrode assembly 3 comprises a membrane electrode body 31 and a frame 32, wherein the frame 32 is fixedly connected to the outer periphery of the membrane electrode body 31, and second through holes 33 corresponding to the first through holes 24 are respectively provided at the two ends of the frame 32, and a sealing glue line 321 corresponding to the glue groove 21 on the lower surface 23 is provided on the upper surface of the frame 32, and the specific steps include:

[0037] Place the first mold 1 on a workbench, wherein the first mold 1 comprises a plate body, a positioning member 14 and a mounting member 12, wherein the plate body is provided with a plurality of positioning grooves 11 and a plurality of first mounting grooves 13, wherein the positioning member 14 is inserted into the positioning groove 11 to position the three sides of the bipolar plate 2, wherein the first mounting groove 13 corresponds to the first through hole 24 and the second through hole 33 one by one, and the mounting member 12 is inserted into the first mounting groove 13;

[0038] Glue is applied in the glue groove 21 on the upper surface 22 of the bipolar plate 2, and the lower surface 23 of the bipolar plate 2 after glue application is placed in contact with the upper surface of the first mold 1, and the mounting member 12 passes through the first through hole 24;

[0039] The lower surface of the membrane electrode assembly 3 is placed in contact with the upper surface 22 of the bipolar plate 2, and the mounting member 12 passes through the second through hole 33;

[0040] The lower surface of the second mold 4 is placed in contact with the upper surface of the membrane electrode assembly 3 to obtain a bonding unit. The second mold 4 is provided with a groove 41 and a plurality of second mounting holes. The groove 41 is provided on the lower surface of the second mold 4. The second mounting holes are provided on both sides of the second mold 4. The groove 41 is consistent in shape with the glue line groove 21 on the bipolar plate 2. The groove 41 is engaged with the sealing glue line 321. The mounting member 12 passes through the first through hole 24, the second through hole 33 and the second mounting groove 42 in sequence;

[0041] The bonding unit is placed in a hot pressing device, and the heating temperature and heating time are set for hot pressing. After the hot pressing is completed, the first and second molds 4 are removed in sequence to obtain the bonded bipolar plate 2 and membrane electrode assembly 3.

[0042] In this embodiment, the bipolar plate 2 and the membrane electrode assembly 3 are both existing products, and the positive and negative surfaces of the bipolar plate 2 are provided with glue line grooves 21, and both ends of the bipolar plate 2 are provided with first through holes 24. The membrane electrode assembly 3 is composed of a membrane electrode body 31 and a frame 32, and the upper surface of the frame 32 is provided with a sealing glue line 321 that can be engaged with the glue line groove 21 on the bipolar plate 2, and both ends of the frame 32 are provided with second through holes 33, and the first through holes 24 and the second through holes 33 correspond to each other one by one and are completely the same. When bonding, it is only necessary to pass the bipolar plate 2 and the membrane electrode assembly 3 with glue on the upper surface 22 through the mounting member 12 in sequence and attach them to the first mold 1, so that the upper surface 22 of the bipolar plate 2 is attached to the lower surface of the membrane electrode assembly 3, and then attach the second mold 4 to the membrane electrode assembly 3, and make the mounting member 12 engage with the second mounting groove 42 to obtain a bonding unit, put the bonding unit into a hot pressing device, set a suitable heating temperature and heating time to heat, and after heating, remove the first and second molds 4 to obtain a firmly bonded bipolar plate 2 and membrane electrode assembly 3. This method can achieve close bonding between the bipolar plate 2 and the membrane electrode assembly 3, and there will be no offset between the two during bonding and transportation, and it can effectively prevent the leakage of internal gas and liquid.

[0043] Furthermore, the glue applied in the glue line groove 21 on the upper surface 22 of the bipolar plate 2 is epoxy glue, and the hot pressing device used is a hot press.

[0044] In order to determine the appropriate heating temperature and heating time, the applicant conducted several experiments, and the experimental results are as follows:

[0045] Table 1

[0046] Temperature ℃ Heating time min Effect 80 5 The glue is not fully cured 90 5 The glue is completely cured 100 4 The glue is completely cured 110 3 The glue is completely cured 120 2 The glue is completely cured 130 1 The glue is completely cured and wrinkles appear on the border

[0047] As can be seen from Table 1, when the heating temperature is set to 80°C, the glue still cannot be completely cured after 5 minutes of heating, so the temperature needs to be increased to 90°C to completely cure the glue; when the heating temperature is increased to 120°C, the glue can be completely cured in only 2 minutes, and the components are not deformed; when the heating temperature is increased to 130°C, the glue is completely cured after only 1 minute of heating, but the frame 32 of the membrane electrode assembly 3 is deformed due to the high temperature. Therefore, it can be determined that the appropriate heating temperature is 90-120°C and the appropriate heating time is 2-5 minutes.

[0048] Furthermore, the mounting member 12 includes a first boss 121 and a second boss 122, the cross-sectional area of ​​the first boss 121 is smaller than that of the second boss 122, the first boss 121 is used to engage with the first mounting groove 13, and the second boss 122 is used to engage with the second mounting groove 42. Such a configuration can facilitate engagement with the first mounting groove 13 and the second mounting groove 42, and facilitate removal of the first and second molds 4 after hot pressing is completed.

[0049] The present application also provides another bonding method for the bipolar plate 2 and the membrane electrode assembly 3, which differs from the above-mentioned bonding method for the bipolar plate 2 and the membrane electrode assembly 3 only in that the bonding unit is placed in a curing device, and a suitable curing time and curing power are set for curing.

[0050] In this embodiment, the glue applied in the glue line groove 21 on the upper surface 22 of the bipolar plate 2 is shadowless glue, and the curing device is a UV curing furnace.

[0051] In order to determine the appropriate curing time and curing power, the applicant conducted several experiments, and the experimental results are as follows:

[0052] Table 2

[0053] <![CDATA[UV curing power mW / cm 2 > UV curing time Effect 300 30 The glue is not fully cured 300 45 The glue is not fully cured 300 60 The glue is not fully cured 450 30 The glue is not fully cured 450 45 The glue is completely cured 450 60 The glue is completely cured 550 30 The glue is completely cured 550 45 The glue is completely cured 550 60 The glue is completely cured 600 30 The glue is completely cured and the frame is deformed

[0054] From Table 2, it can be seen that when the curing power is set to 300mW / cm 2 After 60 seconds, the glue still cannot be completely cured, so the curing power needs to be increased to 450mW / cm 2 To make the glue completely cured; when the curing power is increased to 450mW / cm 2 , only 30s cannot make the glue completely cured, so the curing time is increased to 45s, at which time the glue is completely cured and the parts are not deformed; when the curing power is increased to 550mW / cm 2 , the glue is completely cured in just 30 seconds, and the parts are not deformed; when the curing power is increased to 600mW / cm 2When the glue is completely cured in just 30 seconds, the frame 32 of the membrane electrode assembly 3 is deformed due to the high temperature. Therefore, the appropriate curing power can be determined to be 450-550 mW / cm 2 The appropriate curing time is 45 to 60 seconds.

[0055] The present application also provides a proton exchange membrane fuel cell, comprising a plurality of bipolar plates 2 and a plurality of membrane electrode assemblies 3, wherein the plurality of bipolar plates 2 and the plurality of membrane electrode assemblies 3 are sequentially bonded by the above-mentioned bonding method of the bipolar plates 2 and the membrane electrode assemblies 3. The assembly method of the proton exchange membrane fuel cell is simple, and the bipolar plates 2 and the membrane electrode assemblies 3 are firmly bonded and have good sealing properties. During transportation, the bipolar plates 2 and the membrane electrode assemblies 3 will not be offset, and the performance of the fuel cell will not be affected.

[0056] In summary, the bonding method of the bipolar plate 2 and the membrane electrode assembly 3 provided in this embodiment adopts a specific mold to position the bipolar plate 2 and the membrane electrode assembly 3 so that they can be accurately positioned and bonded, and a certain hot pressing or curing method is used to make the bonding firm, which can effectively prevent the bipolar plate 2 and the membrane electrode assembly 3 from shifting during the preparation and transportation process, affecting the sealing effect of the two, and preventing the leakage of internal gas and liquid.

[0057] This specification discloses the present application with reference to the accompanying drawings, and also enables those skilled in the art to implement the present application, including making and using any device or system, using suitable materials, and using any combined method. The scope of the present application is defined by the technical solution for protection, and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the technical solution for protection, or such other examples contain equivalent structural elements that are not substantially different from the literal language of the technical solution for protection, such other examples should be considered to be within the scope of protection determined by the technical solution for protection of the present application.

Claims

1. A method for bonding a bipolar plate to a membrane electrode assembly, wherein the bipolar plate is provided with a plurality of glue line grooves and a plurality of first through holes, wherein the plurality of glue line grooves are respectively provided along the circumferential sides of the upper and lower surfaces of the bipolar plate, and the plurality of first through holes are symmetrically provided at both ends of the bipolar plate, wherein the membrane electrode assembly comprises a membrane electrode body and a frame, wherein the frame is fixedly connected to the outer periphery of the membrane electrode body, and second through holes corresponding to the first through holes are respectively provided at both ends of the frame, and a sealing glue line corresponding to the glue line groove on the lower surface is provided on the upper surface of the frame, wherein: include: Placing a first mold on a workbench, wherein the first mold comprises a plate body, a positioning member and a mounting member, wherein the plate body is provided with a plurality of positioning grooves and a plurality of first mounting grooves, wherein the positioning member is inserted into the positioning grooves for positioning the three sides of the bipolar plate, wherein the first mounting grooves correspond to the first through holes and the second through holes one by one, and wherein the mounting member is inserted into the first mounting grooves; Apply glue in the glue line groove on the upper surface of the bipolar plate, and place the lower surface of the bipolar plate after glue application in contact with the upper surface of the first mold, with the mounting member passing through the first through hole; Placing the lower surface of the membrane electrode assembly in contact with the upper surface of the bipolar plate, and passing the mounting member through the second through hole; The lower surface of the second mold is placed in contact with the upper surface of the membrane electrode assembly to obtain a bonding unit, the second mold is provided with a groove and a plurality of second mounting holes, the groove is provided on the lower surface of the second mold, the second mounting holes are provided on both sides of the second mold, the groove is consistent with the shape of the glue line groove on the bipolar plate, the groove is engaged with the sealing glue line, and the mounting piece passes through the first through hole, the second through hole and the second mounting groove in sequence; The bonding unit is placed in a hot pressing device, and the heating temperature and heating time are set for hot pressing. After the hot pressing is completed, the first and second molds are removed in sequence to obtain a bonded bipolar plate and membrane electrode assembly.

2. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 1, characterized in that: The mounting member includes a first boss and a second boss, the cross-sectional area of ​​the first boss is smaller than that of the second boss, the first boss is used to engage with the first mounting groove, and the second boss is used to engage with the second mounting groove.

3. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 2, characterized in that: The glue is epoxy glue.

4. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 3, characterized in that: The hot pressing device is a hot press.

5. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 4, characterized in that: The heating temperature is 90-120° C., and the heating time is 2-5 minutes.

6. A method for bonding a bipolar plate to a membrane electrode assembly, characterized in that: The first mold, the second mold, the bipolar plate and the membrane electrode assembly in the bonding method of the bipolar plate and the membrane electrode assembly according to claim 1 specifically include: Placing the first mold on a workbench, and inserting the positioning member and the mounting member into the positioning groove and the first mounting groove respectively; Apply glue in the glue line groove on the upper surface of the bipolar plate, and place the lower surface of the bipolar plate after glue application in contact with the upper surface of the first mold, with the mounting member passing through the first through hole; Placing the lower surface of the membrane electrode assembly in contact with the upper surface of the bipolar plate, and passing the mounting member through the second through hole; The lower surface of the second mold is placed on the upper surface of the membrane electrode assembly to obtain a bonding unit, the groove is engaged with the sealing glue line, and the mounting member passes through the first through hole, the second through hole and the second mounting groove in sequence; The bonding unit is placed in a curing device, and the curing time and curing power are set for hot pressing. After the curing is completed, the first and second molds are removed in sequence to obtain a bonded bipolar plate and membrane electrode assembly.

7. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 6, characterized in that: The glue is shadowless glue.

8. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 7, characterized in that: The curing device is a UV curing oven.

9. The method for bonding a bipolar plate to a membrane electrode assembly according to claim 8, characterized in that: The curing time is 45 to 60 seconds and the curing power is 450 to 550 mW / cm 2 .

10. A proton exchange membrane fuel cell, characterized in that: It comprises a plurality of bipolar plates and a plurality of membrane electrode assemblies, wherein the plurality of bipolar plates and the plurality of membrane electrode assemblies are bonded in sequence by the bonding method of bipolar plates and membrane electrode assemblies as described in any one of claims 1 to 9.

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