A membrane electrode and its preparation process

Abstract

The present invention discloses a membrane electrode and its preparation process, belonging to the technical field of membrane electrodes, and solves the problem that the gap between the diffusion layer and the frame gradually becomes larger, and then the solution medium on the outside enters between the frame and the diffusion layer, further shortening the service life of the entire membrane electrode. It includes an electrode plate, sealing plates fixedly connected to both sides thereof, two V-shaped clamping parts I and two V-shaped clamping parts II. Extension parts I are integrally formed on both sides of the V-shaped clamping part I, and a receiving groove I for accommodating the electrode plate is formed between the two extension parts I on both sides. The extension part I and the sealing plate are hermetically arranged. The present invention can use the V-shaped clamping part II to keep the V-shaped clamping part I and the extension part I in a state of always clamping the electrode plate, and then keep a small gap between the extension part I, the sealing plate and the electrode plate all the time, so that the diffusion layer, the catalytic layer and the proton exchange membrane will not be in direct contact with the solution medium, and thus the service life of the entire membrane electrode can be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane electrodes, and particularly to a membrane electrode and a preparation process thereof. Background Art

[0002] A membrane electrode assembly (MEA) is the most core component of a proton exchange membrane fuel cell, mainly composed of three key materials, namely a proton exchange membrane, a catalyst layer, and a diffusion layer, and a frame. The commonly referred to membrane electrode assembly is a seven-layer membrane electrode, including a proton exchange membrane, an anode catalyst layer and a cathode catalyst layer, an anode diffusion layer and a cathode diffusion layer, and a gasket for sealing and fixing.

[0003] After the membrane electrode is used for a long time, its working life will gradually shorten. Especially when the thicknesses of the proton exchange membrane, the catalyst, and the gas diffusion layer become thinner due to the use of the proton exchange membrane, the catalyst layer, and the diffusion layer, the gap between the diffusion layer and the frame will gradually increase. Subsequently, the external solution medium will enter between the frame and the diffusion layer, further shortening the service life of the entire membrane electrode. Therefore, it is necessary to ensure the sealing between the frame and the diffusion layer.

[0004] Therefore, a membrane electrode and a preparation process thereof are proposed to solve or alleviate the above problems. Summary of the Invention

[0005] The purpose of the present invention is to solve the drawbacks existing in the prior art, and to propose a membrane electrode and a preparation process thereof.

[0006] In order to achieve the above purpose, the present invention adopts the following technical scheme:

[0007] A membrane electrode includes an electrode plate, sealing plates fixedly connected to both sides thereof, two V-shaped clamping parts I and two V-shaped clamping parts II. Extension parts I are integrally formed on both sides of the V-shaped clamping part I. A receiving groove I for receiving the electrode plate is formed between the two extension parts I. The extension part I and the sealing plate are hermetically arranged. A sealing strip clamped by the extension part I is wrapped around the outer peripheral wall of the electrode plate. The V-shaped clamping part I and the V-shaped clamping part II are integrally formed into an X-shaped structure, and both have elastic deformation properties. Extension parts II are also integrally formed on both sides of the V-shaped clamping part II. A receiving groove II with a variable volume is formed between the two extension parts II. The receiving groove II is hermetically arranged externally, and a tension spring for attempting to control the volume reduction is fixedly connected in the receiving groove II.

[0008] Preferably, the ends of the V-shaped clamp part 1 and the V-shaped clamp part 2 are jointly provided with a connecting component, and the connecting component controls the volume of the accommodating groove 1 and the accommodating groove 2 to be proportional, and a plurality of attachment lines are provided at the connection between the V-shaped clamp part 1 and the V-shaped clamp part 2.

[0009] Preferably, a through hole with the same length direction as the two is provided at the connection between the V-shaped clamp part 1 and the V-shaped clamp part 2, and the connecting component includes two overlapping Z-shaped connecting pieces, a hinge pin, and a plurality of bolts. The Z-shaped connecting piece is provided with a through groove connected to the through hole, and the two Z-shaped connecting pieces in the single-sided connecting component are overlapped, and the hinge pins are jointly penetrated in the through groove and the through hole at both ends. Semicircular grooves recessed inwardly are provided at both ends of the Z-shaped connecting piece, and threaded holes are provided on both sides of the V-shaped clamp part 1 and the V-shaped clamp part 2, and the bolts pass through the semicircular grooves and are threadedly connected to the threaded holes.

[0010] Preferably, overlapping pieces 1 are fixedly connected at both ends of the sealing plate, and overlapping pieces 2 are fixedly connected at one end of the extension part 1 away from the V-shaped clamp part 1. The overlapping pieces 1 and 2 are overlapped, and the sum of their thicknesses is equal to the thickness of the sealing plate and the extension part 1. Sealant is filled between the overlapping pieces 1 and 2, between the overlapping pieces 1 and the extension part 1, and between the overlapping pieces 2 and the sealing plate.

[0011] Preferably, the triangular space between the electrode plate and the first receiving groove is filled with a soft rubber block, and the soft rubber block is also located in the sealing strip.

[0012] Preferably, the sealing strip includes a straight piece wrapped around the outside of the electrode plate, and a special-shaped piece wrapped around the soft rubber block and located in the first receiving groove.

[0013] Preferably, a shielding sheet with elastic deformation performance is fixedly connected between the second extension parts on both sides, and the shielding sheet closes the second accommodating groove and is sealed.

[0014] Preferably, the electrode plate comprises a proton exchange membrane, a catalyst layer fixedly connected to both sides thereof, and a diffusion layer fixedly connected to a side of the catalyst layer away from the proton exchange membrane.

[0015] Preferably, a threaded through groove is formed on the first overlapping piece, and a threaded groove communicating with the threaded through groove is formed on the second overlapping piece, and a connecting screw is connected between the threaded groove and the inner thread of the threaded through groove.

[0016] The present invention also provides a process for preparing a membrane electrode, comprising the following steps:

[0017] Step 1, take the electrode plate, the sealing plate, the soft rubber block, and the sealing strip, place the two soft rubber blocks against the two ends of the electrode plate, and wrap the sealing strip around the outer circumference of the electrode plate and the soft rubber block, and then clamp the two sealing plates on the outside;

[0018] Step 2: Weld both ends of the tension spring to both sides of the second receiving groove, and then close the second receiving groove with the shielding piece by hot pressing, so that the tension spring reduces the volume of the second receiving groove, and fix the connecting assembly at both ends of the first V-shaped clamping part and the second V-shaped clamping part.

[0019] Step 3: Coat sealant on the first overlapping piece, then fit the first V-shaped clamping part with the soft rubber block to make the first overlapping piece and the second overlapping piece fit together, and press and seal them to the sealing plate and the electrode plate through a cold pressing process until the sealant cures, and threadedly connect the connecting screw to the threaded through groove and the threaded groove.

[0020] The present invention has the following beneficial effects:

[0021] The present invention can clamp the first V-shaped clamping part and the first extension part by the second V-shaped clamping part, so that the electrode plate is always in a clamped state. This clamped state ensures that there is a small gap between the first extension part and the sealing plate and the electrode plate, so as to realize the separation between components such as the diffusion layer, the catalytic layer and the proton exchange membrane and the solution medium. Since there is no direct contact with the solution medium, the service life of the membrane electrode is increased.

[0022] In this clamped state, the function of the second V-shaped clamping part is to clamp the first V-shaped clamping part and the first extension part by applying appropriate pressure to ensure that the electrode plate always maintains a tight connection state. This helps to prevent direct contact between the diffusion layer, the catalytic layer and the proton exchange membrane and the solution medium, thereby reducing the influence of impurities in the solution medium on the electrode assembly and prolonging the life of the membrane electrode. At the same time, by maintaining a small gap, it also helps to improve the efficiency and stability of the electrode reaction.

[0023] Therefore, the function of the second V-shaped clamping part in the membrane electrode is to clamp the first extension part of the electrode plate and the sealing plate to ensure a small gap with the solution medium, so as to realize the effective separation of the membrane electrode and improve its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic structural diagram of the present invention;

[0025] Figure 2 is Figure 1 the enlarged view of part A in

[0026] Figure 3 is Figure 1 the enlarged view of part B in

[0027] Figure 4 is a cross-sectional view of the present invention;

[0028] Figure 5 is Figure 4 the enlarged view of part C in

[0029] Figure 6 For Figure 4 the enlarged view at position D in

[0030] Figure 7 the structural schematic diagram of the sealing strip in the present invention;

[0031] Figure 8 For Figure 7 the enlarged view at position E in

[0032] 1. Sealing plate; 11. First overlapping piece; 2. First V-shaped clamping part; 21. Second overlapping piece; 3. Second V-shaped clamping part; 31. Tensile spring; 4. Sealing strip; 41. Straight piece; 42. Shaped piece; 43. Soft rubber block; 5. Shielding piece; 61. Z-shaped connecting piece; 62. Hinge pin; 63. Bolt; 71. Proton exchange membrane; 72. Catalytic layer; 73. Diffusion layer. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0034] A membrane electrode, as Figures 1-8 shown, includes an electrode plate, a sealing plate 1 fixedly connected to both sides thereof, and two first V-shaped clamping parts 2 and two second V-shaped clamping parts 3. The electrode plate includes a proton exchange membrane 71, catalytic layers 72 fixedly connected to both sides thereof, and a diffusion layer 73 fixedly connected to the side of the catalytic layer 72 away from the proton exchange membrane 71. The first V-shaped clamping part 2 and the second V-shaped clamping part 3 are integrally formed into an X-shaped structure, and both have elastic deformation performance.

[0035] On both sides of the first V-shaped clamping part 2, there are integrally formed first extension parts. The first extension parts are in the shape of flat plates, and a first accommodation groove for accommodating the electrode plate is formed between the two first extension parts on both sides. On both sides of the second V-shaped clamping part 3, there are also integrally formed second extension parts. The second extension parts are also in the shape of flat plates, and a second accommodation groove with a variable volume is formed between the two second extension parts on both sides. The second accommodation groove is externally sealed, and a tensile spring 31 that attempts to control the volume reduction is fixedly connected inside the second accommodation groove. A shielding piece 5 with elastic deformation performance is fixedly connected between the two second extension parts on both sides. The shielding piece 5 closes the second accommodation groove and is sealed.

[0036] The first extension parts are hermetically arranged with the sealing plate 1, and a sealing strip 4 clamped by the first extension parts is wrapped on the outer peripheral wall of the electrode plate. A soft rubber block 43 is filled in the triangular space between the electrode plate and the first accommodation groove. The soft rubber block 43 is made of fluororubber and is in the shape of a triangular prism. The soft rubber block 43 is also located in the sealing strip 4. The sealing strip 4 includes a straight piece 41 wrapped on the outside of the electrode plate and a shaped piece 42 wrapped around the soft rubber block 43 and located in the first accommodation groove. The sealing strip 4 is made of polyethylene.

[0037] The two ends of the sealing plate 1 are fixedly connected with overlapping pieces 11, and the end of the extension part 1 away from the V-shaped clamp part 2 is fixedly connected with overlapping piece 21, the overlapping piece 11 and the overlapping piece 21 are overlapped, and the sum of their thicknesses is equal to the thickness of the sealing plate 1 and the extension part 1, and sealant is filled between the overlapping piece 11 and the overlapping piece 21, between the overlapping piece 11 and the extension part 1, and between the overlapping piece 21 and the sealing plate 1. A threaded groove is provided on the overlapping piece 11, and a threaded groove connected to the threaded groove is provided on the overlapping piece 21, and a connecting screw is connected to the threaded groove and the inner thread of the threaded groove.

[0038] The ends of the V-shaped clamp part 1 2 and the V-shaped clamp part 2 3 are jointly provided with a connecting component, and the connecting component controls the volume of the accommodating groove 1 and the accommodating groove 2 to be proportional, and a through hole with the same length direction as the two is opened at the connection between the V-shaped clamp part 1 2 and the V-shaped clamp part 2 3, and the connecting component includes two overlapping Z-shaped connecting pieces 61, a hinge pin 62, and a plurality of bolts 63, and a through groove connected to the through hole is opened on the Z-shaped connecting piece 61, and the two Z-shaped connecting pieces 61 in the single-sided connecting component are overlapped, and the hinge pin 62 is jointly penetrated in the through groove and the through hole at both ends, and the two ends of the Z-shaped connecting piece 61 are provided with inwardly concave semicircular grooves, and threaded holes are opened on both sides of the V-shaped clamp part 1 2 and the V-shaped clamp part 2 3, and the bolts 63 pass through the semicircular grooves and are threadedly connected with the threaded holes.

[0039] A plurality of attachment lines are provided at the connection between the V-shaped clamping part 1 2 and the V-shaped clamping part 2 3 .

[0040] The preparation process of the membrane electrode comprises the following steps:

[0041] Step 1, take the electrode plate, the sealing plate 1, the soft rubber block 43, and the sealing strip 4, place the two soft rubber blocks 43 against the two ends of the electrode plate, and wrap the sealing strip 4 around the outer periphery of the electrode plate and the soft rubber block 43, and then clamp the two sealing plates 1 on the outside;

[0042] Step 2, welding the two ends of the tension spring 31 to the two sides of the receiving groove 2, and then closing the receiving groove 2 with the shielding sheet 5 by hot pressing, so that the tension spring 31 reduces the volume of the receiving groove 2, and fixing the connecting assembly to the two ends of the V-shaped clamp part 1 2 and the V-shaped clamp part 2 3;

[0043] Step 3, apply sealant on the overlapping sheet 11, then fit the V-shaped clamp 1 2 with the soft rubber block 43 to fit the overlapping sheet 11 and the overlapping sheet 2 21, and press the sealing plate 1 and the electrode plate together through a cold pressing process until the sealant is cured, and thread the connecting screws with the threaded groove and the threaded groove.

[0044] When this membrane electrode is in use, the peripheral wall of the electrode plate can be wrapped and sealed by the sealing strip 4. With the arrangement of the soft rubber block 43, it can be filled into the first accommodating groove, enabling the first extension part to clamp the electrode plate, reducing the gap between the first V-shaped clamping part 2 and the electrode plate. At the same time, the second overlapping piece 21 overlaps with the first overlapping piece 11 on the sealing plate 1, and sealant and connecting screws are provided to fill the gap between the sealing plate 1 and the first V-shaped clamping part 2, thus ensuring the sealing effect at this place. In addition, the shielding piece 5 seals and shields the second accommodating groove to prevent the solution medium from entering it. Since the tension spring 31 pulls the inner wall of the second accommodating groove, the second V-shaped clamping part 3 transmits the acting force through the Z-shaped connecting piece 61, reducing the volume of the second accommodating groove and correspondingly reducing the volume of the first accommodating groove, enabling the second extension part to clamp the electrode plate through the sealing plate 1. When the thickness of the electrode plate becomes smaller, due to the arrangement of the soft rubber block 43, when the first accommodating groove shrinks, even if the thickness of the electrode plate shrinks, the first V-shaped clamping part 2 can still clamp and compress the soft rubber block 43 through the first extension part, making it always keep in a state of fitting with the electrode plate. The setting of the connecting component makes the first V-shaped clamping part 2 and the second V-shaped clamping part 3 have better integrity. Even if they are not a truly hinged structure but an integrally formed structure, they can still achieve a state similar to a hinged structure through the connecting component to complete the transmission of the acting force, so that when the second accommodating groove shrinks, the first accommodating groove will also shrink accordingly.

[0045] Meanwhile, due to the arrangement of the adhesion lines, the solid impurities generated by the solution medium during use can adhere to the connection between the first V-shaped clamping part 2 and the second V-shaped clamping part 3, preventing the volumes of the first accommodating groove and the second accommodating groove from further expanding, thus enabling this membrane electrode to always have a good sealing effect.

[0046] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes, should be covered by the protection scope of the present invention.

Claims

1. A membrane electrode, characterized in that, It includes an electrode plate, sealing plates (1) fixedly connected to both sides thereof, two V-shaped clamping parts one (2), and two V-shaped clamping parts two (3). On both sides of the V-shaped clamping part one (2), there are integrally formed extension parts one. Between the two extension parts one on both sides, there is a receiving groove one for receiving the electrode plate. The extension part one and the sealing plate (1) are hermetically arranged. And on the outer peripheral wall of the electrode plate, there is a sealing strip (4) clamped by the extension part one. The V-shaped clamping part one (2) and the V-shaped clamping part two (3) are integrally formed into an X-shaped structure, and both have elastic deformation properties. And the V-shaped clamping part two (3) is used to clamp the V-shaped clamping part one (2) and the extension part one so that the electrode plate is always in a clamped state. On both sides of the V-shaped clamping part two (3), there are also integrally formed extension parts two. Between the two extension parts two on both sides, there is a receiving groove two with a variable volume. The receiving groove two is hermetically arranged outside, and inside the receiving groove two, there is a tension spring (31) fixedly connected and attempting to control the volume reduction.

2. The membrane electrode according to claim 1, wherein, At the ends of the V-shaped clamping part one (2) and the V-shaped clamping part two (3), there is a connecting component in common. The connecting component controls the volumes of the receiving groove one and the receiving groove two to be proportional. At the connection of the V-shaped clamping part one (2) and the V-shaped clamping part two (3), there are several adhering lines provided.

3. A membrane electrode according to claim 2, characterized in that, At the connection of the V-shaped clamping part one (2) and the V-shaped clamping part two (3), there is a through hole in the same direction as their lengths. The connecting component includes two overlapping Z-shaped connecting pieces (61), a hinge pin (62), and several bolts (63). On the Z-shaped connecting piece (61), there is a through slot communicating with the through hole. The two Z-shaped connecting pieces (61) in one-sided connecting component are overlapped, and the hinge pin (62) is commonly inserted into the through slots and the through hole at both ends. At both ends of the Z-shaped connecting piece (61), there are semi-circular grooves recessed inward. On both sides of the V-shaped clamping part one (2) and the V-shaped clamping part two (3), there are threaded holes. The bolts (63) pass through the semi-circular grooves and are threadedly connected to the threaded holes.

4. A membrane electrode according to claim 1, wherein At both ends of the sealing plate (1), there are fixedly connected overlapping pieces one (11). At the end of the extension part one far from the V-shaped clamping part one (2), there is fixedly connected an overlapping piece two (21). The overlapping piece one (11) and the overlapping piece two (21) are overlapped, and the sum of their thicknesses is equal to the thicknesses of the sealing plate (1) and the extension part one. Between the overlapping piece one (11) and the overlapping piece two (21), between the overlapping piece one (11) and the extension part one, and between the overlapping piece two (21) and the sealing plate (1), there is sealant filled.

5. A membrane electrode according to claim 1, characterized in that, In the triangular space existing between the electrode plate and the receiving groove one, there is a soft rubber block (43) filled. The soft rubber block (43) is also located in the sealing strip (4).

6. A membrane electrode according to claim 5, characterized in that, The sealing strip (4) includes a straight piece (41) wrapped around the outside of the electrode plate, and a special-shaped piece (42) wrapped around the soft rubber block (43) and located in the receiving groove one.

7. A membrane electrode according to claim 1, characterized in that, Between the two extension parts two on both sides, there is fixedly connected a shielding piece (5) with elastic deformation properties. The shielding piece (5) closes the receiving groove two and is hermetically arranged.

8. A membrane electrode according to claim 1, characterized in that The electrode plate comprises a proton exchange membrane (71), a catalytic layer (72) fixedly connected to both sides thereof, and a diffusion layer (73) fixedly connected to a side of the catalytic layer (72) away from the proton exchange membrane (71).

9. A membrane electrode according to claim 4, characterized in that, The overlapping piece 1 (11) is provided with a threaded groove, and the overlapping piece 2 (21) is provided with a threaded groove connected to the threaded groove. The threaded groove and the threaded groove are internally threadedly connected with a connecting screw.

10. A preparation process of a membrane electrode for preparing the membrane electrode according to any one of claims 1-9, characterized in that, The following steps are included: Step 1, take the electrode plate, the sealing plate (1), the soft rubber block (43), and the sealing strip (4), place the two soft rubber blocks (43) against the two ends of the electrode plate, and wrap the sealing strip (4) around the outer circumference of the electrode plate and the soft rubber block (43), and then clamp the two sealing plates (1) on the outside; Step 2, welding the two ends of the tension spring (31) to the two sides of the receiving groove 2, and then closing the receiving groove 2 with the shielding sheet (5) by hot pressing, so that the tension spring (31) reduces the volume of the receiving groove 2, and fixing the connecting assembly to the two ends of the V-shaped clamping part 1 (2) and the V-shaped clamping part 2 (3), and clamping the V-shaped clamping part 1 (2) and the extension part 1 by the V-shaped clamping part 2 (3) so that the electrode plate is always in a clamped state; Step 3, apply sealant on the overlapping sheet 1 (11), then engage the V-shaped clamp part 1 (2) with the soft rubber block (43) to engage the overlapping sheet 1 (11) and the overlapping sheet 2 (21), and press the sealing plate (1) and the electrode plate together through a cold pressing process until the sealant is cured, and thread the connecting screws with the threaded groove and the threaded groove.

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