Method for bonding bipolar plates to membrane electrode assemblies and proton exchange membrane fuel cell

Abstract

The application relates to the technical field, in particular to a method for bonding a bipolar plate and a membrane electrode assembly and a proton exchange membrane fuel cell, which comprises the following steps: a bipolar plate, which is provided with a plurality of glue line grooves and a plurality of first through holes, is bonded with a membrane electrode assembly which comprises a membrane electrode body and a frame, the bipolar plate and the membrane electrode assembly, which are coated with glue on the upper surfaces, are sequentially adhered to a first mold through an installation piece, so that the upper surface of the bipolar plate is adhered to the lower surface of the membrane electrode assembly, and a positioning piece fixes three edges of the bipolar plate and the membrane electrode assembly; a second mold is adhered to the membrane electrode assembly to obtain a bonding unit; the bonding unit is placed into a hot pressing device for hot pressing; after the hot pressing is completed, the first and second molds are removed to obtain the bipolar plate and the membrane electrode assembly which are firmly bonded; the method can realize the close bonding of the bipolar plate and the membrane electrode assembly, the two will not be deviated during the bonding and transportation, and the internal gas and liquid can be effectively prevented from leaking.

Description

TECHNICAL FIELD

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

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

[0003] Proton exchange membrane fuel cell is composed of end plate, membrane electrode assembly and bipolar plate, and the specific steps are as follows: first, place a end plate on the assembly platform, place the bipolar plate on the end plate, and ensure that the positioning structure of the end plate and the bipolar plate are accurately matched. Then place the prepared membrane electrode assembly on the bipolar plate, align the anode side of the membrane electrode assembly with the anode bipolar plate, and align the cathode side of the membrane electrode assembly with the cathode bipolar plate. According to the above method, stack the bipolar plate and the membrane electrode assembly in turn. After completing the stacking of all bipolar plates and membrane electrode assemblies, place another end plate on the top, and also accurately align and preliminarily position it with the components below. Finally, use a special clamp or press to apply uniform pressure to the assembled cell stack, so that the components are tightly attached to each other. At the same time of applying pressure, use bolts, nuts, straps or welding to firmly fix the two end plates together, so that the entire cell stack maintains a stable structure.

[0004] In the above assembly process, the membrane electrode assembly and the bipolar plate may deviate during stacking and assembly due to inaccurate positioning, resulting in internal gas and liquid leakage. In addition, the proton exchange membrane fuel cell assembled by the above method is also prone to deviation of the membrane electrode assembly and the bipolar plate during transportation, which affects the performance of the fuel cell. Therefore, it is considered to tightly adhere the membrane electrode assembly to one side of the bipolar plate, and then repeat the stacking, so as to reduce the risk of deviation of the membrane electrode assembly and the bipolar plate. SUMMARY

[0005] The purpose of the present application is to provide a method for bonding bipolar plate and membrane electrode assembly and a proton exchange membrane fuel cell, which tightly adheres the membrane electrode assembly to one 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 object, the application adopts a kind of bonding method of bipolar plate and membrane electrode assembly, a plurality of glue line grooves and a plurality of first through holes are formed on the bipolar plate, a plurality of glue line grooves are formed along the circumferential side of the upper surface and the lower surface of the bipolar plate respectively, a plurality of first through holes are symmetrically arranged at the two ends of the bipolar plate, the membrane electrode assembly includes membrane electrode body and frame, the frame is fixedly connected to the outer periphery of the membrane electrode body, the two ends of the frame are provided with second through holes corresponding to the first through holes, and the upper surface of the frame is provided with sealing glue lines corresponding to the glue line grooves on the lower surface, comprising:

[0007] Place the first mold on the workbench, the first mold includes a plate body, a positioning member and a mounting member, a plurality of positioning grooves and a plurality of first mounting grooves are formed on the plate body, the positioning member is inserted into the positioning groove for positioning three sides of the bipolar plate, the first mounting groove corresponds to the first through hole and the second through hole one by one, and the mounting member is inserted into the first mounting groove.

[0008] Glue is applied to the glue line groove on the upper surface of the bipolar plate, the lower surface of the bipolar plate after glue application is placed in close contact with the upper surface of the first mold, and the mounting member passes through the first through hole.

[0009] Place the lower surface of the membrane electrode assembly in close contact with the upper surface of the bipolar plate, and the mounting member passes through the second through hole.

[0010] Place the lower surface of the second mold in close contact with the upper surface of the membrane electrode assembly to obtain a bonding unit, a groove and a plurality of second mounting holes are formed on the second mold, the groove is arranged on the lower surface of the second mold, the second mounting hole is arranged on the two 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 member is engaged in sequence through the first through hole, the second through hole and the second mounting groove.

[0011] Place the bonding unit into a hot pressing device, set the heating temperature and heating time for hot pressing, and then sequentially remove the first and second molds 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 for engaging with the first mounting groove, and the second boss is used for engaging 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 application also provides another method for bonding a bipolar plate and a membrane electrode assembly, which adopts the first mold, the second mold, the bipolar plate and the membrane electrode assembly in the above-mentioned method for bonding a bipolar plate and a membrane electrode assembly, and specifically comprises the following steps:

[0017] The first mold is placed on a workbench, and the positioning member and the mounting member are respectively inserted into the positioning groove and the first mounting groove;

[0018] Glue is applied to the glue line groove on the upper surface of the bipolar plate, the lower surface of the bipolar plate after being applied with glue is placed against the upper surface of the first mold, and the mounting member passes through the first through hole;

[0019] The lower surface of the membrane electrode assembly is placed against the upper surface of the bipolar plate, and the mounting member passes through the second through hole;

[0020] The lower surface of the second mold is placed against the upper surface of the membrane electrode assembly to obtain a bonding unit, the recess and the sealing glue line are clamped, and the mounting member sequentially passes through the first through hole, the second through hole and the second mounting groove to be clamped;

[0021] The bonding unit is placed in a curing device, and a curing time and a curing power are set to perform hot pressing, after curing is completed, the first mold and the second mold are sequentially removed 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 furnace.

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

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

[0026] The application discloses a method for bonding a bipolar plate and a membrane electrode assembly. The method comprises the following steps: manufacturing a first mold and a second mold, the first mold comprising a second mold with a plurality of positioning grooves and a plurality of mounting pieces, placing the lower surface of the bipolar plate on the first mold and positioning the three sides of the bipolar plate by the plurality of positioning pieces, placing the membrane electrode assembly on the upper surface of the bipolar plate coated with glue, and placing the second mold on the membrane electrode assembly to obtain a bonding unit, wherein the mounting pieces are inserted into the first mounting grooves and sequentially pass through the first through holes, the second through holes and the second mounting grooves. Then, the bonding unit is placed in a hot pressing device, and appropriate heating temperature and heating time are set to hot press the bonding unit. After the 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. In the above process, the membrane electrode assembly and the bipolar plate will not be deviated during the bonding process, and the internal gas and liquid will not be leaked, so that the deviation risk of the membrane electrode assembly and the bipolar plate is effectively reduced. The membrane electrode assembly and the bipolar plate are firmly bonded, and the safe transportation is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0027] The application will be described in further detail in connection with the attached drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of explaining the preferred embodiments and therefore should not be regarded as limiting the scope of the application. In addition, unless specifically indicated, the drawings are only intended to conceptually represent the composition or structure of the described objects and can include exaggerated displays, and the drawings are not necessarily drawn to scale.

[0028] Figure 1 It is a schematic view of the bipolar plate of the application;

[0029] Figure 2 It is a schematic view of the membrane electrode assembly of the application;

[0030] Figure 3 It is a schematic view of the bonding unit of the application;

[0031] Figure 4 It is a schematic view of the mounting piece of the application;

[0032] Figure 5 It is a schematic view of the second mold of the application;

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

[0034] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0035] In the description of the present application, it should be understood that the terms "front", "back", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0036] Please refer to Figures 3-5 A method for bonding a bipolar plate 2 and a membrane electrode assembly 3 is provided in an embodiment of the present application, the bipolar plate 2 is provided with a plurality of glue line grooves 21 and a plurality of first through holes 24, the plurality of glue line grooves 21 are respectively provided along the circumferential sides of the upper surface 22 and the lower surface 23 of the bipolar plate 2, the plurality of first through holes 24 are symmetrically provided at the two ends of the bipolar plate 2, the membrane electrode assembly 3 includes a membrane electrode body 31 and a frame 32, the frame 32 is fixedly connected to the outer periphery of the membrane electrode body 31, the two ends of the frame 32 are respectively provided with second through holes 33 corresponding to the first through holes 24, and the upper surface of the frame 32 is provided with sealing glue lines 321 corresponding to the glue line grooves 21 on the lower surface 23, and the specific steps include:

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

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

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

[0040] The lower surface of the second mold 4 is placed in close 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 arranged on the lower surface of the second mold 4, the second mounting holes are arranged 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, and the mounting piece 12 is engaged with 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 hot pressing is performed by setting the heating temperature and the heating time, after the hot pressing is completed, the first and the second mold 4 are removed in sequence to obtain the bonded bipolar plate 2 and the membrane electrode assembly 3.

[0042] In the embodiment, the bipolar plate 2 and the membrane electrode assembly 3 are both existing products, the bipolar plate 2 is provided with glue line grooves 21 on both the positive and negative surfaces, and the bipolar plate 2 is provided with first through holes 24 at both ends. The membrane electrode assembly 3 is composed of a membrane electrode body 31 and a frame 32, the upper surface of the frame 32 is provided with a sealing glue line 321 which can be engaged with the glue line groove 21 on the bipolar plate 2, and the frame 32 is provided with second through holes 33 at both ends, the first through holes 24 and the second through holes 33 correspond to each other and are completely identical. When bonding, the bipolar plate 2 and the membrane electrode assembly 3 whose upper surfaces 22 are coated with glue are placed in close contact with the first mold 1 in sequence through the mounting piece 12, so that the upper surface 22 of the bipolar plate 2 is placed in close contact with the lower surface of the membrane electrode assembly 3, then the second mold 4 is placed in close contact with the membrane electrode assembly 3, and the mounting piece 12 is engaged with the second mounting groove 42 to obtain a bonding unit, the bonding unit is placed in a hot pressing device, and heating is performed by setting appropriate heating temperature and heating time, after the heating is completed, the first and the second mold 4 are removed to obtain the firmly bonded bipolar plate 2 and the membrane electrode assembly 3. The method can realize the close bonding of the bipolar plate 2 and the membrane electrode assembly 3, and the two will not deviate from each other during the bonding and transportation, and can effectively prevent the internal gas and liquid from leaking.

[0043] Further, the glue 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 has conducted multiple experiments, and the experimental results are as follows:

[0045] Table 1

[0046] Temperature °C Heating time min Effect 80 5 Glue not fully cured 90 5 Glue fully cured 100 4 Glue fully cured 110 3 Glue fully cured 120 2 Glue fully cured 130 1 Glue fully cured, frame creased

[0047] As shown in Table 1, when the heating temperature is set to 80°C, the glue cannot be completely cured even 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 do not deform; when the heating temperature is increased to 130°C, the glue is completely cured in only 1 minute, but the frame 32 of the membrane electrode assembly 3 deforms due to the high temperature. Therefore, the appropriate heating temperature is determined to be 90-120°C, and the appropriate heating time is 2-5 minutes.

[0048] Further, 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 be engaged with the first mounting groove 13, and the second boss 122 is used to be engaged with the second mounting groove 42. In this way, the first mounting groove 13 and the second mounting groove 42 can be engaged conveniently, and the first and second molds 4 can be removed conveniently after hot pressing.

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

[0050] In the embodiment, the glue 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 has conducted many experiments, and the experimental results are as follows:

[0052] Table 2

[0053] UV cure power mW / cm 2 ]] UV curing time s Effect 300 30 Glue not fully cured 300 45 Glue not fully cured 300 60 Glue not fully cured 450 30 Glue not fully cured 450 45 Glue fully cured 450 60 Glue fully cured 550 30 Glue fully cured 550 45 Glue fully cured 550 60 Glue fully cured 600 30 Glue fully cured, frame deformed

[0054] As shown in Table 2, when the curing power is set to 300 mW / cm 2 , the glue cannot be completely cured even after 60 seconds of curing, so the curing power needs to be increased to 450 mW / cm 2 to completely cure the glue; when the curing power is increased to 450 mW / cm 2 , the glue cannot be completely cured in only 30 seconds, so the curing time is increased to 45 seconds, at which time the glue is completely cured and the components do not deform; when the curing power is increased to 550 mW / cm 2 , the glue is completely cured in only 30 seconds and the components do not deform; when the curing power is increased to 600 mW / cm 2In this case, the adhesive is completely cured in only 30 seconds, but the frame 32 of the membrane electrode assembly 3 is deformed due to the high temperature. Therefore, it is determined that the appropriate curing power is 450 to 550 mW / cm2 2 and 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, the plurality of bipolar plates 2 and the plurality of membrane electrode assemblies 3 being sequentially bonded by the above-mentioned bonding method of the bipolar plate 2 and the membrane electrode assembly 3. The assembly method of the proton exchange membrane fuel cell is simple, and the bonding between the bipolar plate 2 and the membrane electrode assembly 3 is firm and has good sealing performance, and the phenomenon of the shift of the bipolar plate 2 and the membrane electrode assembly 3 during transportation does not occur, which does not affect the performance of the fuel cell.

[0056] In summary, the bonding method of the bipolar plate 2 and the membrane electrode assembly 3 provided in the present embodiment uses 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 shift of the bipolar plate 2 and the membrane electrode assembly 3 during preparation and transportation, affect the sealing effect of the two, and prevent the leakage of the 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 manufacturing and using any device or system, using appropriate materials, and using any combined method. The scope of the present application is defined by the claimed technical solutions, and includes other examples thought by those skilled in the art. As long as such other examples include structural elements not different from the literal language of the claimed technical solutions, or such other examples contain equivalent structural elements not substantially different from the literal language of the claimed technical solutions, such other examples should be considered to be within the protection scope determined by the claimed technical solutions of the present application.

Claims

1. A method for bonding a bipolar plate and a membrane electrode assembly, the bipolar plate having a plurality of glue line grooves and a plurality of first through holes, the plurality of glue line grooves being respectively formed along the circumferential sides of the upper and lower surfaces of the bipolar plate, and the plurality of first through holes being symmetrically arranged at the two ends of the bipolar plate, the membrane electrode assembly comprising a membrane electrode body and a frame, the frame being fixedly connected to the outer periphery of the membrane electrode body, the two ends of the frame respectively having second through holes corresponding to the first through holes, and the upper surface of the frame being provided with sealing glue lines corresponding to the glue line grooves on the lower surface, characterized in that, The application relates to a method for bonding a bipolar plate and a membrane electrode assembly. The first mold is placed on a workbench, the first mold comprises a plate body, positioning pieces and mounting pieces, a plurality of positioning grooves and a plurality of first mounting grooves are formed in the plate body, the positioning pieces are inserted into the positioning grooves to position three side edges of the bipolar plate, the first mounting grooves correspond to the first through holes and the second through holes one by one, and the mounting pieces are inserted into the first mounting grooves; Glue is applied to the glue line groove on the upper surface of the bipolar plate, the lower surface of the bipolar plate after being applied with glue is placed in close contact with the upper surface of the first mold, and the mounting pieces pass through the first through holes; The lower surface of the membrane electrode assembly is placed in close contact with the upper surface of the bipolar plate, and the mounting pieces pass through the second through holes; The lower surface of the second mold is placed in close contact with the upper surface of the membrane electrode assembly to obtain a bonding unit, a groove and a plurality of second mounting holes are formed in the second mold, the groove is arranged on the lower surface of the second mold, the second mounting holes are arranged on two sides of the second mold, the groove is consistent in shape with the glue line groove on the bipolar plate, the groove is clamped with the sealant glue line, and the mounting pieces pass through the first through holes, the second through holes and the second mounting grooves in sequence and are clamped; The bonding unit is placed in a hot pressing device, heating temperature and heating time are set to perform hot pressing, after the hot pressing is completed, the first mold and the second mold are removed in sequence, and a bonded bipolar plate and membrane electrode assembly are obtained; The mounting pieces comprise first bosses and second bosses, the cross-sectional area of the first bosses is smaller than that of the second bosses, the first bosses are used for clamping the first mounting grooves, and the second bosses are used for clamping the second mounting grooves.

2. The method of bonding a bipolar plate to a membrane electrode assembly of claim 1, wherein, The glue is epoxy glue.

3. The method of bonding a bipolar plate to a membrane electrode assembly of claim 2, wherein, The hot pressing device is a hot press.

4. The method of bonding a bipolar plate to a membrane electrode assembly of claim 3, wherein, The heating temperature is 90-120 DEG C, and the heating time is 2-5 min.

5. A method of bonding a bipolar plate to a membrane electrode assembly, characterized by, The first mold, the second mold, the bipolar plate and the membrane electrode assembly in the method are used, and the method specifically comprises the following steps: The first mold is placed on the workbench, the positioning pieces and the mounting pieces are respectively inserted into the positioning grooves and the first mounting grooves; Glue is applied to the glue line groove on the upper surface of the bipolar plate, the lower surface of the bipolar plate after being applied with glue is placed in close contact with the upper surface of the first mold, and the mounting pieces pass through the first through holes; The lower surface of the membrane electrode assembly is placed in close contact with the upper surface of the bipolar plate, and the mounting pieces pass through the second through holes; The lower surface of the second mold is placed in close contact with the upper surface of the membrane electrode assembly to obtain a bonding unit, the groove is clamped with the sealant glue line, and the mounting pieces pass through the first through holes, the second through holes and the second mounting grooves in sequence and are clamped; The bonding unit is placed in a curing device, curing time and curing power are set to perform hot pressing, after the curing is completed, the first mold and the second mold are removed in sequence, and a bonded bipolar plate and membrane electrode assembly are obtained.

6. The method of bonding a bipolar plate to a membrane electrode assembly of claim 5, wherein, The glue is shadowless glue.

7. The method of bonding a bipolar plate to a membrane electrode assembly of claim 6, wherein, The curing device is a UV curing furnace.

8. The method of bonding a bipolar plate to a membrane electrode assembly of claim 7, wherein, The curing time is 45-60 s, and the curing power is 450-550 mW / cm2.

9. A proton exchange membrane fuel cell characterized by A fuel cell stack comprising a plurality of bipolar plates and a plurality of membrane electrode assemblies, the plurality of bipolar plates and the plurality of membrane electrode assemblies being sequentially bonded by the method of bonding a bipolar plate to a membrane electrode assembly according to any one of claims 1 to 8.

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