A sealing structure of an integrated membrane electrode fuel cell

Abstract

The application relates to the technical field of fuel cells, and discloses a sealing structure of an integrated membrane electrode fuel cell, which comprises a membrane electrode, a first bipolar plate and a second bipolar plate, a first sealing line is fixedly arranged on one side of the membrane electrode close to the first bipolar plate, a second sealing line is fixedly arranged on one side of the membrane electrode close to the second bipolar plate, the height of the cross section of the first sealing line is defined as h1, the width of the cross section of the first sealing line is defined as w1, 0.7 < h1 / w1 <= 1, the height of the cross section of the second sealing line is defined as h2, the width of the cross section of the second sealing line is defined as w2, 0.2 < h2 / w2 < 0.6, and w1 is smaller than w2. If the first sealing line is slightly offset, the offset amount is still within the pressure bearing range of the second sealing line, the membrane electrode frame cannot be deformed and tilted due to the fact that the stress points of the two sealing lines are not on the same vertical line, the structure of the membrane electrode frame is prevented from being damaged due to the shearing force between the bipolar plate and the sealing line, the membrane electrode is prevented from being cracked, the structural stability of the membrane electrode frame is improved, and the service life of the fuel cell stack is prolonged.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a sealed structure for an integrated membrane electrode fuel cell. Background Technology

[0002] A fuel cell (PEMFC) is a power generation device that converts the chemical energy of fuel into electrical energy through a chemical reaction. Fuel cells have advantages such as high power density, high conversion rate, and low environmental pollution. Membrane electrode assembly (MEA) and bipolar plates are key components of a fuel cell stack. The bipolar plate includes a cathode plate and an anode plate with a flow field. The MEA includes a reaction zone and a supporting frame, placed between the anode and cathode plates. The reaction zone provides a catalyst to support the electrochemical reaction, while the frame supports the reaction zone and isolates the anode and cathode plates to prevent short circuits. Since a fuel cell contains gaseous media such as hydrogen and air, as well as a cooling medium such as ethylene glycol, sealing components are needed between the MEA and the cathode and anode plates to prevent leakage of these media.

[0003] A common sealing method involves placing an elastomeric seal on each side of the membrane electrode and then applying pressure for compression sealing. One type of compression sealing involves placing a seal on each side of the membrane electrode before compression; this method typically requires the seal to be pre-fixed to the bipolar plate, making the assembly process more complex. Another type of compression sealing integrates the seal directly with the membrane electrode (also known as an integrated membrane electrode), which simplifies the assembly process. Currently, the commonly used integrated membrane electrode sealing structure typically features sealing lines on both sides of the membrane electrode with similar geometric shapes and dimensions, such as circles, ellipses, or trapezoids.

[0004] In existing technologies, if the cross-sectional geometry and dimensions of the sealing lines on both sides of the integrated membrane electrode are similar, shear forces may occur between the bipolar plates and the sealing lines during the stacking of single cells or a small number of cells into a fuel cell stack under the applied compressive force. At this time, the edges of the sealing lines at the contact surfaces with the membrane electrode frame will pull on the membrane electrode frame under the shear force, potentially causing cracking of the membrane electrode. It can also easily lead to the centers of the contact surfaces between the sealing lines and the bipolar plates on both sides of the membrane electrode not being on a straight line perpendicular to the membrane electrode plane. This results in asymmetrical stress on both sides of the membrane electrode frame, leading to poor structural stability of the membrane electrode frame, affecting the durability of the membrane electrode and sealing structure, and thus impacting the fuel cell stack's lifespan.

[0005] In the existing technology, if the cross-sectional area of ​​the sealing line is increased in order to reduce membrane electrode damage, it is highly likely that when assembly pressure is applied during the assembly process of fuel cell stack, the contact surface between the sealing line and the bipolar plate will form a "hydraulic lock" effect. This will prevent the sealing line from undergoing the corresponding "flattening" deformation when the assembly pressure increases, thereby increasing the risk of the bipolar plate being crushed and the required sealing effect not being achieved. Summary of the Invention

[0006] The purpose of this invention is to provide a sealed structure for an integrated membrane electrode fuel cell, in order to solve the problem in the prior art where, during the assembly of a fuel cell stack, shear forces generated between the bipolar plates and the membrane electrode cause the sealing line to pull on the membrane electrode frame, leading to cracking of the membrane electrode and affecting the structural stability of the membrane electrode frame and the lifespan of the fuel cell stack.

[0007] To achieve the above objectives, the present invention provides a sealing structure for an integrated membrane electrode fuel cell, comprising a membrane electrode, a first bipolar plate, and a second bipolar plate. The membrane electrode is disposed between the first bipolar plate and the second bipolar plate. A first sealing line is fixedly disposed on the side of the membrane electrode near the first bipolar plate, and a second sealing line is fixedly disposed on the side of the membrane electrode near the second bipolar plate. The height of the cross-section of the first sealing line is defined as h1, and the width is defined as w1, where 0.7 < h1 / w1 ≤ 1. The height of the cross-section of the second sealing line is defined as h2, and the width is defined as w2, where 0.2 < h2 / w2 < 0.6. Furthermore, the width w1 of the first sealing line is less than the width w2 of the second sealing line.

[0008] Preferably, the width w2 of the second sealing line is greater than or equal to twice the width w1 of the first sealing line.

[0009] Preferably, the height h1 of the first sealing line is less than the height h2 of the second sealing line.

[0010] Preferably, the height h2 of the second sealing line is greater than or equal to twice the height h1 of the first sealing line.

[0011] Preferably, the first sealing line includes a first sealing body, and the second sealing line includes a second sealing body and a sealing flange integrally formed with the second sealing body. The first sealing body and the second sealing body are located on a vertical line of the membrane electrode, and the sealing flange is located on one side of the second sealing body.

[0012] Preferably, there are two second sealing bodies, and the sealing flange is arranged between the two second sealing bodies. There are also two first sealing bodies, and the two first sealing bodies correspond one-to-one with the two second sealing bodies.

[0013] Preferably, the first bipolar plate has a first sealing groove for embedding the first sealing line, and the width of the first sealing groove is greater than the width of the first sealing line; the second bipolar plate has a second sealing groove for embedding the second sealing line, and the width of the second sealing groove is greater than the width of the second sealing line.

[0014] Preferably, the depth of the first sealing groove is defined as H1, where H1 < h1; and the depth of the second sealing groove is defined as H2, where H2 < h2.

[0015] Compared with existing technologies, the sealing structure of the integrated membrane electrode fuel cell of this invention has the following advantages: the height of the first sealing line is less than its width, and it has a flat shape. At the same time, the height of the second sealing line is much smaller than its width, making it less prone to displacement. Furthermore, the width of the second sealing line is greater than that of the first sealing line, giving it a larger pressure-bearing area. If the first sealing line deviates slightly, the displacement will still be within the pressure-bearing range of the second sealing line. The membrane electrode frame will not be skewed or deformed due to the force points of the two sealing lines not being on the same vertical line. This avoids structural damage to the membrane electrode frame caused by the shear force between the bipolar plate and the sealing line, prevents membrane electrode cracking, improves the structural stability of the membrane electrode frame, and increases the service life of the fuel cell stack. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the sealing structure of the integrated membrane electrode fuel cell of the present invention;

[0017] Figure 2 This is a schematic diagram of another embodiment of the sealing structure of the integrated membrane electrode fuel cell of the present invention.

[0018] In the figure, 1 is the membrane electrode; 2 is the first bipolar plate; 3 is the second bipolar plate; 4 is the first sealing line; 41 is the first sealing body; 5 is the second sealing line; 51 is the second sealing body; 52 is the sealing flange; 6 is the first sealing groove; and 7 is the second sealing groove. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] A preferred embodiment of the sealing structure of an integrated membrane electrode fuel cell according to the present invention, such as... Figure 1As shown, the sealed structure of the integrated membrane electrode fuel cell includes a membrane electrode 1, a first bipolar plate 2, and a second bipolar plate 3. One of the first bipolar plate 2 and the second bipolar plate 3 serves as the anode plate, and the other serves as the cathode plate. The membrane electrode 1 is arranged between the first bipolar plate 2 and the second bipolar plate 3. The membrane electrode 1, the first bipolar plate 2, and the second bipolar plate 3 work together to form a complete single cell. Multiple single cells are connected in series to form a fuel cell stack.

[0021] The membrane electrode 1 is an integrated membrane electrode 1. A first sealing line 4 is fixedly arranged on the side of the membrane electrode 1 near the first bipolar plate 2, and a second sealing line 5 is fixedly arranged on the side of the membrane electrode 1 near the second bipolar plate 3. Both the first sealing line 4 and the second sealing line 5 are arranged on the frame of the membrane electrode 1. The first sealing line 4 is used to prevent the medium from leaking out between the membrane electrode 1 and the first bipolar plate 2, and the second sealing line 5 is used to prevent the medium from leaking out between the membrane electrode 1 and the second bipolar plate 3. Both the first sealing line 4 and the second sealing line 5 are made of elastic material. The method of fixing the first sealing line 4 and the second sealing line 5 to the membrane electrode 1 is not limited, and existing processes such as bonding, dispensing, or injection molding can be used for fixing.

[0022] The height of the cross-section of the first sealing line 4 is defined as h1, and the width as w1, where 0.7 < h1 / w1 ≤ 1. The height of the cross-section of the first sealing line 4 is the distance between the highest point of the cross-section and the edge of the membrane electrode 1, and the height of the first sealing line 4 is the farthest distance between the two ends of the cross-section. The height of the first sealing line 4 is less than its width, and it has a flat shape, making it less prone to displacement.

[0023] The height of the cross section of the second sealing line 5 is defined as h2 and the width as w2, 0.2 < h2 / w2 < 0.6. The height of the cross section of the second sealing line 5 is the distance between the highest point of the cross section and the frame of the membrane electrode 1. The height of the second sealing line 5 is the farthest distance between the two ends of the cross section. The width w1 of the first sealing line 4 is less than the width w2 of the second sealing line 5.

[0024] Specifically, in this embodiment, h1 / w1 can be 0.75, 0.8, 0.85, 0.9, 0.95, or 1; h2 / w2 can be 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or 0.55.

[0025] The height of the second sealing line 5 is much smaller than its width, making it less prone to displacement. Furthermore, the width of the second sealing line 5 is greater than that of the first sealing line 4, giving the second sealing line 5 a larger pressure-bearing area. If the first sealing line 4 is slightly displaced, the displacement will still be within the pressure-bearing range of the second sealing line 5. The frame of the membrane electrode 1 will not be skewed or deformed due to the force points of the two sealing lines not being on the same vertical line. This avoids structural damage to the frame of the membrane electrode 1 caused by the shear force between the bipolar plate and the sealing line, prevents the membrane electrode 1 from cracking, improves the structural stability of the frame of the membrane electrode 1, and increases the service life of the fuel cell stack.

[0026] Preferably, the width w2 of the second sealing line 5 is greater than or equal to twice the width w1 of the first sealing line 4.

[0027] Increasing the width of the second sealing line 5 can further increase the pressure-bearing range of the second sealing line 5. If the first sealing line 4 shifts under pressure, it can ensure that the first sealing line 4 will not exceed the pressure-bearing range of the second sealing line 5. The first sealing line 4 and the second sealing line 5 will not be misaligned. The frame of the membrane electrode 1 will not be skewed or deformed because the stress points of the two sealing lines are not on the same vertical line. This avoids structural damage to the frame of the membrane electrode 1 due to the shear force between the bipolar plate and the sealing line, and prevents the membrane electrode 1 from cracking.

[0028] Preferably, the height h1 of the first sealing line 4 is less than the height h2 of the second sealing line 5.

[0029] When applying assembly pressure during the assembly of the fuel cell stack, increasing the height of the second sealing line 5 can reduce the hydraulic locking effect between the second sealing line 5 and the contact surfaces of the membrane electrode 1 and the bipolar plate, thereby preventing the bipolar plate from being crushed and ensuring the sealing effect.

[0030] Preferably, the height h2 of the second sealing line 5 is greater than or equal to twice the height h1 of the first sealing line 4.

[0031] The height of the second sealing line 5 is further increased, which can effectively reduce the hydraulic lock effect while ensuring the sealing effect.

[0032] Preferably, such as Figure 2 As shown, the first sealing line 4 includes a first sealing body 41, and the second sealing line 5 includes a second sealing body 51 and a sealing flange 52 integrally formed with the second sealing body 51. The first sealing body 41 and the second sealing body 51 are located on the vertical line of the membrane electrode 1, and the sealing flange 52 is located on one side of the second sealing body 51.

[0033] The second sealing body 51 and the sealing flange 52 are integrally formed. The sealing flange 52 is located on one side of the second sealing body 51. The sealing flange 52 increases the total width of the second sealing line 5. When the first sealing line 4 deviates slightly, it will not exceed the pressure bearing range of the second sealing line 5, thereby preventing shear force from being generated between the sealing line and the bipolar plate and pulling the frame of the membrane electrode 1, and preventing the membrane electrode 1 from cracking.

[0034] Meanwhile, the second sealing body 51 is the main stress-bearing part of the second sealing line 5 and the main structure that produces the sealing effect. The arrangement of the sealing flange 52 can effectively increase the width of the second sealing line 5. While ensuring the ratio of the width to the height of the second sealing line 5, the height of the second sealing body 51 can be effectively increased, thereby effectively reducing the hydraulic locking effect of the second sealing line 5.

[0035] Preferably, there are two second sealing bodies 51, and a sealing flange 52 is arranged between the two second sealing bodies 51. There are two first sealing bodies 41, and the two first sealing bodies 41 correspond one-to-one with the two second sealing bodies 51.

[0036] The provision of two first sealing bodies 41 and two second sealing bodies 51 prevents the sealing line from shifting under pressure. If the highest point of the first sealing line 4 shifts under pressure, it will not exceed the pressure range of the second sealing line 5, thus ensuring the sealing effect and mitigating the unbalanced force applied by the sealing line to the frame of the membrane electrode 1, which could lead to damage to the frame of the membrane electrode 1.

[0037] Preferably, the first bipolar plate 2 has a first sealing groove 6 for embedding the first sealing line 4, and the width of the first sealing groove 6 is greater than the width of the first sealing line 4; the second bipolar plate 3 has a second sealing groove 7 for embedding the second sealing line 5, and the width of the second sealing groove 7 is greater than the width of the second sealing line 5.

[0038] The width of the first sealing groove 6 is greater than the width of the first sealing line 4, and the width of the second sealing groove 7 is greater than the width of the second sealing line 5. This ensures that the first sealing groove 6 and the second sealing groove 7 respectively accommodate the first sealing line 4 and the second sealing line 5, thereby limiting the first sealing line 4 and the second sealing line 5 and guiding the two sealing lines when they deform, thus improving the sealing effect.

[0039] Preferably, the groove depth of the first sealing groove 6 is defined as H1, where H1 < h1; and the groove depth of the second sealing groove 7 is defined as H2, where H2 < h2.

[0040] The depth of the first sealing groove 6 is less than the height of the first sealing line 4, and the depth of the second sealing groove 7 is less than the height of the second sealing line 5. When assembling the fuel cell stack, the first sealing groove 6 applies pressure to the first sealing line 4, and the second sealing groove 7 applies pressure to the second sealing line 5 to ensure the sealing effect.

[0041] In summary, the embodiments of the present invention provide a sealing structure for an integrated membrane electrode fuel cell. The height of the first sealing line is less than its width, and it has an overall flat shape. At the same time, the height of the second sealing line is much smaller than its width, making it less prone to displacement. Furthermore, the width of the second sealing line is greater than the width of the first sealing line, giving it a larger pressure-bearing area. If the first sealing line is slightly displaced, the displacement amount remains within the pressure-bearing range of the second sealing line. The membrane electrode frame will not be skewed or deformed due to the force points of the two sealing lines not being on the same vertical line. This avoids structural damage to the membrane electrode frame caused by the shear force between the bipolar plate and the sealing line, prevents membrane electrode cracking, improves the structural stability of the membrane electrode frame, and increases the service life of the fuel cell stack.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A sealed structure for an integrated membrane electrode fuel cell, characterized in that, The device includes a membrane electrode, a first bipolar plate, and a second bipolar plate. The membrane electrode is disposed between the first bipolar plate and the second bipolar plate. A first sealing line is fixedly disposed on the side of the membrane electrode closer to the first bipolar plate, and a second sealing line is fixedly disposed on the side of the membrane electrode closer to the second bipolar plate. The height of the cross-section of the first sealing line is defined as h1, and the width is w1, where 0.7 < h1 / w1 ≤ 1. The height of the cross-section of the second sealing line is defined as h2, and the width is w2, where 0.2 < h2 / w2 < 0.

6. Furthermore, the width w1 of the first sealing line is less than the width w2 of the second sealing line.

2. The sealing structure of the integrated membrane electrode fuel cell according to claim 1, characterized in that, The width w2 of the second sealing line is greater than or equal to twice the width w1 of the first sealing line.

3. The sealing structure of the integrated membrane electrode fuel cell according to claim 1, characterized in that, The height h1 of the first sealing line is less than the height h2 of the second sealing line.

4. The sealing structure of the integrated membrane electrode fuel cell according to claim 3, characterized in that, The height h2 of the second sealing line is greater than or equal to twice the height h1 of the first sealing line.

5. The sealed structure of the integrated membrane electrode fuel cell according to any one of claims 1-4, characterized in that, The first sealing line includes a first sealing body, and the second sealing line includes a second sealing body and a sealing flange integrally formed with the second sealing body. The first sealing body and the second sealing body are located on the vertical line of the membrane electrode, and the sealing flange is located on one side of the second sealing body.

6. The sealing structure of the integrated membrane electrode fuel cell according to claim 5, characterized in that, There are two second sealing bodies, and the sealing flange is arranged between the two second sealing bodies. There are two first sealing bodies, and the two first sealing bodies correspond one-to-one with the two second sealing bodies.

7. The sealing structure of the integrated membrane electrode fuel cell according to any one of claims 1-4, characterized in that, The first bipolar plate has a first sealing groove for embedding the first sealing line, and the width of the first sealing groove is greater than the width of the first sealing line; the second bipolar plate has a second sealing groove for embedding the second sealing line, and the width of the second sealing groove is greater than the width of the second sealing line.

8. The sealing structure of the integrated membrane electrode fuel cell according to claim 7, characterized in that, The depth of the first sealing groove is defined as H1, where H1 < h1; the depth of the second sealing groove is defined as H2, where H2 < h2.

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