Bipolar plate common channel anti-corrosion protection structure and fuel cell
By setting protective strips on both sides of the common channel of the bipolar plate to prevent fluid erosion, the corrosion problem of bipolar plates is solved and the safety and stability of the fuel cell is improved.
Patent Information
- Application Number
- CN202422133296.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-08-30
AI Technical Summary
In fuel cells, the common channels of the bipolar plates are prone to corrosion under the erosion of high-pressure reaction gas and cooling water, resulting in electrochemical corrosion and seal failure, affecting the safety of the stack.
A first protective strip and a second protective strip are provided on both sides of the bipolar plate, respectively, extending to the public channel or both ends, blocking fluid erosion and reducing electrochemical corrosion pathways and tip discharge corrosion.
Effectively protect the edge of the bipolar plate, reduce the entry of carbon particles and metal ions into the cooling water, avoid seal failure and increase resistance, and improve stack safety.
Smart Images
Figure CN223140792U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of fuel cells, in particular to an anti-corrosion protection structure for a bipolar plate common channel and a fuel cell. Background Technique
[0002] In a fuel cell, bipolar plates and membrane electrodes are stacked alternately in sequence, and finally auxiliary components such as upper and lower current collectors and upper and lower end plates are added to form a fuel cell stack. After the bipolar plates and membrane electrodes are stacked, the common channels on the bipolar plates and the common channels on the membrane electrodes are superimposed to form the common channel of the fuel cell, and the common channels on the bipolar plates and the common channels on the membrane electrodes have the same size. The common channel includes a reaction gas common channel and a cooling water common channel. The reaction gas common channel is used for the input of reaction gas, the discharge of excessive reaction gas and redundant moisture, and the cooling water common channel undertakes the inlet and outlet of cooling water.
[0003] During the operation of the fuel cell, hydrogen and air enter the fuel cell through the common channel to participate in the electrochemical reaction to generate water, and the residual gas after the reaction is discharged from the stack through the outlet common channel. During the reaction process, cooling water enters the stack from the common channel, absorbs heat, and then leaves the stack from the common channel. Since the reaction gas pressure reaches above 150 kPa and the cooling water pressure reaches above 50 kPa, a large kinetic energy will be formed during the process of the above-mentioned materials entering the stack through the common channel, a large linear velocity will be formed at the edge of the bipolar plate common channel, scouring the common channel, resulting in scouring corrosion at the edge of the bipolar plate common channel. During the operation of the stack, since the sealing material size of the common channel formed by the membrane electrode is the same as the bipolar plate channel size, the distance between two adjacent bipolar plates is relatively close, and an electric potential difference is easily formed between the two bipolar plates, resulting in electrochemical corrosion. Particles and / or metal ions falling off from the edge of the bipolar plate will enter the membrane electrode. The metal ions entering the membrane electrode will penetrate into the proton exchange membrane, and metal ions such as iron, chromium, and nickel will be deposited in the proton exchange membrane to replace the sulfonic acid groups, resulting in problems such as a decrease in the water content of the proton exchange membrane, a decrease in proton conductivity, a thinning of the membrane, corrosion of the catalyst carrier, and a decrease in catalytic activity. For molded graphite plates and engraved graphite bipolar plates, the strength of the material itself is not high. During long-term operation, the common channel part is continuously corroded and thinned, the common channel becomes larger, and finally the strength of the gasket is affected, resulting in seal failure and endangering the safety of the stack. Content of the Utility Model
[0004] The purpose of the utility model is to provide an anti-corrosion protection structure for a bipolar plate common channel and a fuel cell, which can block the direct scouring of the airflow and cooling water on the side walls of the double common channels, and effectively reduce the formation of an electrochemical corrosion path due to the potential difference between the upper and lower bipolar plates and the tip discharge corrosion of the charges at the edge of the bipolar plate.
[0005] To achieve the above purpose, the utility model provides the following technical solutions:
[0006] In a first aspect, the present utility model provides an anti-corrosion protection structure for a bipolar plate common channel, including a bipolar plate, a first protection strip, and a second protection strip;
[0007] The bipolar plate has a first side and a second side disposed opposite to each other, and the bipolar plate is provided with a common channel penetrating through the first side and the second side;
[0008] The first protection strip is located on the first side, the second protection strip is located on the second side and is disposed opposite to the first protection strip, and both the first protection strip and the second protection strip extend into the common channel or respectively extend to both ends of the common channel to block the direct scouring of the fluid on the side surface of the common channel.
[0009] Further, the first protection strip and the membrane electrode on one side of the bipolar plate adopt an integral structure, and the second protection strip and the membrane electrode on the other side of the bipolar plate adopt an integral structure.
[0010] Further, when the first protection strip and the second protection strip respectively extend to both ends of the common channel, the extending directions of the first protection strip and the second protection strip are parallel to the bipolar plate.
[0011] Further, when both the first protection strip and the second protection strip extend into the common channel, the ends of the first protection strip and the second protection strip extending into the common channel are hermetically connected.
[0012] Further, the common channel has a plurality of side surfaces connected in sequence, at least one side surface is an air inlet and water inlet surface, and the first protection strip and the second protection strip are not provided at both ends of the air inlet and water inlet surface along the depth direction of the common channel.
[0013] Further, the air inlet and water inlet surface is covered with a protective layer, and the material of the protective layer is polyvinylidene fluoride.
[0014] Further, the first protection strip and the gasket on one side of the bipolar plate adopt an integral structure, and the second protection strip and the gasket on the other side of the bipolar plate adopt an integral structure.
[0015] Further, both the first protection strip and the second protection strip are independently arranged from the membrane electrodes and gaskets on both sides of the bipolar plate.
[0016] Further, both the first protection strip and the second protection strip extend into the common channel, and the ends extending into the common channel are hermetically connected, and the first protection strip and the second protection strip adopt an integral structure.
[0017] In a second aspect, the present utility model further provides a fuel cell, which includes the bipolar plate common channel anti-corrosion protection structure described in the above solution.
[0018] The bipolar plate common channel anti-corrosion protection structure and the fuel cell provided by the present utility model can produce the following beneficial effects:
[0019] Compared with the prior art, for the bipolar plate common channel anti-corrosion protection structure provided in the first aspect of the present utility model, a first protection strip and a second protection strip are respectively arranged on both sides of the bipolar plate. Since both the first protection strip and the second protection strip can extend into the common channel or respectively extend to both ends of the common channel, the first protection strip and the second protection strip can fully separate the edges of the upper and lower bipolar plates that form the common channel, blocking the direct scouring of the air flow and cooling water on the side wall of the common channel, protecting the edges of the bipolar plate that form the common channel, effectively reducing the formation of an electrochemical corrosion path due to the potential difference between the upper and lower bipolar plates and the tip discharge corrosion of charges at the edges of the bipolar plate, and further alleviating the increase in the conductivity of the cooling water caused by the carbon particles and / or metal ions falling off from the edges of the bipolar plate entering the cooling water, the easy sealing failure of the gasket, and the increase in the plate resistance caused by the reduction of metal ions on the surface of the cooling water chamber to form an oxide layer.
[0020] The fuel cell provided in the second aspect of the present utility model has the bipolar plate common channel anti-corrosion protection structure provided in the first aspect of the present utility model, and thus has all the beneficial effects of the bipolar plate common channel anti-corrosion protection structure provided in the first aspect of the present utility model. Description of the Drawings
[0021] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0022] Figure 1 It is a schematic structural diagram of a bipolar plate provided by an embodiment of the present utility model;
[0023] Figure 2 It is a cross-sectional view of an anti-corrosion protection structure provided by Embodiment 1 of the present utility model;
[0024] Figure 3 It is a cross-sectional view of an anti-corrosion protection structure provided by Embodiment 2 of the present utility model;
[0025] Figure 4 It is a schematic structural diagram of a membrane electrode provided by an embodiment of the present utility model;
[0026] Figure 5 is Figure 4 a partial enlarged view of part A of
[0027] Figure 6 a schematic structural diagram of a gasket provided in Embodiment III of the present utility model;
[0028] Figure 7 a cross-sectional view of an anti-corrosion protection structure provided in Embodiment IV of the present utility model.
[0029] Reference numerals: 1 - bipolar plate; 11 - first side; 12 - second side; 13 - common channel; 14 - air inlet and water inlet surface; 15 - flow field reaction area; 2 - first protection strip; 3 - second protection strip; 4 - membrane electrode; 41 - common cooling water channel; 42 - common reaction gas channel; 43 - original edge of membrane electrode; 44 - improved edge of membrane electrode; 5 - gasket. Specific embodiments
[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts shall fall within the protection scope of the present utility model.
[0031] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model 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 should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0032] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0033] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and understanding the present invention, and are not used to limit the present invention.
[0034] An embodiment of the first aspect of the present invention is to provide an anti-corrosion protection structure for the common channel of bipolar plates, as Figures 1 to 3 shown, including a bipolar plate 1, a first protection strip 2, and a second protection strip 3; the bipolar plate 1 has a first side 11 and a second side 12 arranged opposite to each other, and the bipolar plate 1 is provided with a common channel 13 penetrating the first side 11 and the second side 12; the first protection strip 2 is located on the first side 11, the second protection strip 3 is located on the second side 12 and is arranged opposite to the first protection strip 2, and both the first protection strip 2 and the second protection strip 3 extend into the common channel 13 or respectively extend to both ends of the common channel 13 to block the direct scouring of the fluid on the side of the common channel 13.
[0035] As Figure 1 shown, the bipolar plate 1 is provided with a common channel 13, and a first protection strip 2 and a second protection strip 3 are respectively arranged on the first side 11 and the second side 12 of the bipolar plate 1. The first protection strip 2 and the second protection strip 3 can respectively extend to the upper and lower ends of the common channel 13 as Figure 2 shown, or both can extend into the common channel 13 and be bonded as Figure 3 shown. Through the arrangement of the first protection strip 2 and the second protection strip 3, the upper and lower bipolar plates 1 are fully spaced apart, blocking the direct scouring of the air flow and cooling water on the side wall of the common channel, and protecting the edge of the bipolar plate 1. It avoids the formation of an electrochemical corrosion path due to the potential difference between the upper and lower bipolar plates 1 and the tip discharge corrosion of charges at the edge of the bipolar plate, thereby reducing the carbon particles and / or metal ions falling off from the edge of the bipolar plate into the cooling water and causing an increase in the conductivity of the cooling water. Therefore, it is not necessary to frequently replace the cooling water, nor will it significantly increase the resistance of the bipolar plate.
[0036] According to the structural forms of the first protection strip 2 and the second protection strip 3, it can be divided into the following four embodiments:
[0037] Embodiment 1
[0038] In the first embodiment, the first protection strip 2 and the membrane electrode 4 on one side of the bipolar plate 1 adopt an integrated structure, and the second protection strip 3 and the membrane electrode 4 on the other side of the bipolar plate 1 adopt an integrated structure, that is, as Figure 4 shown, the first protection strip 2 can be regarded as formed by the membrane electrode 4 on the first side 11 of the bipolar plate 1 expanding from the original edge 43 of the membrane electrode to the improved edge 44 of the membrane electrode, and the second protection strip 3 can be regarded as formed by the membrane electrode 4 on the second side 12 of the bipolar plate 1 expanding from the original edge 43 of the membrane electrode to the improved edge 44 of the membrane electrode.
[0039] In the first embodiment, as Figure 2 shown, the first protection strip 2 and the second protection strip 3 respectively extend to the upper and lower ends of the common channel 13, and the extending directions of the first protection strip 2 and the second protection strip 3 are parallel to the bipolar plate 1.
[0040] After the improved membrane electrode 4 is stacked with the bipolar plate 1, the common channel part of the membrane electrode 4 completely covers the common channel part of the bipolar plate 1, ensuring that the material of the common channel part of the membrane electrode 4 can completely separate the edge of the common channel of the bipolar plate 1.
[0041] It can be understood that the common channel of the membrane electrode 4 includes, as Figure 4 shown, a cooling water common channel 41 and a reaction gas common channel 42.
[0042] Embodiment Two
[0043] In the second embodiment, similarly to the first embodiment, the first protection strip 2 and the membrane electrode 4 on one side of the bipolar plate 1 adopt an integral structure, and the second protection strip 3 and the membrane electrode 4 on the other side of the bipolar plate 1 adopt an integral structure.
[0044] In the second embodiment, as Figure 3 shown, both the first protection strip 2 and the second protection strip 3 extend into the common channel 13, and the ends of the first protection strip 2 and the second protection strip 3 extending into the common channel 13 are hermetically connected.
[0045] Specifically, the ends of the first protection strip 2 and the second protection strip 3 extending into the common channel 13 are hermetically connected by fitting or hot pressing.
[0046] In the second embodiment, the common channel 13 has a plurality of side faces connected in sequence. In order to ensure that the bipolar plate 1 can intake air and water normally, at least one side face is an air and water intake face 14, and the remaining side faces are non-air and water intake faces. The first protection strip 2 and the second protection strip 3 are not provided at both ends of the air and water intake face 14 along the depth direction of the common channel 13, that is, the edge of the air and water intake face 14 is flush with the corresponding air and water intake face 14 of the upper and lower membrane electrodes 4.
[0047] Taking Figure 1 as an example, the common channel 13 has four side faces connected in sequence. The face close to the flow field reaction area 15 is the air and water intake face 14. The first protection strip 2 and the second protection strip 3 are not provided at both ends of the air and water intake face 14 along the depth direction of the common channel 13, that is, as Figure 5As shown, the size of the original edge 43 of the membrane electrode is consistent with the size of the common channel 13 on the bipolar plate 1. After improvement, the edge 44 of the membrane electrode extends inward from three sides of the common channel 42 for the reaction gas. Specifically, the right side of the membrane electrode 4 corresponding to the air inlet and water inlet surface 14 is not extended, while the upper side, lower side, and left side of the membrane electrode 4 corresponding to other surfaces are all extended to form protection strips, and the ends of the first protection strip 2 and the second protection strip 3 on the membrane electrodes 4 on both sides of the bipolar plate 1 are hermetically connected.
[0048] In the second embodiment, a protective layer is covered on the air inlet and water inlet surface 14, and the material of the protective layer is polyvinylidene fluoride.
[0049] Polyvinylidene fluoride, also known as PVDF, is a highly non-reactive thermoplastic fluoropolymer, which can form a composite layer on the air inlet and water inlet surface 14 to improve the corrosion resistance of the edge of the bipolar plate 1.
[0050] It can be understood that polyvinylidene fluoride is an existing well-known material, and those skilled in the art can directly purchase and obtain it.
[0051] Embodiment Three
[0052] In the third embodiment, as Figure 6 shown, the first protection strip 2 and the gasket 5 on one side of the bipolar plate 1 adopt an integrated structure, and the second protection strip 3 and the gasket 5 on the other side of the bipolar plate 1 adopt an integrated structure.
[0053] In this third embodiment, by changing the structure of the gaskets 5 on both sides of the bipolar plate 1, at both ends of the common channel, the area of the gasket 5 is expanded and extended to the edge of the bipolar plate 1, preferably exceeding the edge of the bipolar plate 1 to form a protection strip.
[0054] It should be noted that it is necessary to ensure that the thickness of the gasket 5 extending to both ends of the common channel 13 is relatively thin, so that without affecting the assembly force of the fuel cell stack, the overall height of the fuel cell stack does not need to be significantly increased or even increased.
[0055] Embodiment Four
[0056] In the fourth embodiment, as Figure 7 shown, both the first protection strip 2 and the second protection strip 3 are arranged independently of the membrane electrode 4 and the gasket 5 on both sides of the bipolar plate 1.
[0057] In the fourth embodiment, both the first protection strip 2 and the second protection strip 3 extend into the common channel 13, and the ends extending into the common channel 13 are hermetically connected. The first protection strip 2 and the second protection strip 3 adopt an integrated structure to form a protective sleeve, which is nested on the edge of the bipolar plate 1 forming the common channel 13.
[0058] Specifically, the first protection strip 2 and the second protection strip 3 can be made of resin material, and are subjected to high-temperature heat treatment or glue coating treatment, so that the protective sleeve and the bipolar plate 1 are combined into a whole to protect the edge of the bipolar plate 1, which can not only block the erosion of the airflow on the edge of the bipolar plate 1, but also reduce the electrochemical corrosion system formed by the potential difference.
[0059] In the fourth embodiment, by nesting the resin protective sleeve, the edge corrosion of the bipolar plate can be avoided, and at the same time, it does not affect the airflow and the cooling water from entering and leaving the fuel cell stack.
[0060] In the fourth embodiment, both the first protection strip 2 and the second protection strip 3 include a straight extension part and an inclined part. The straight extension part is fixedly connected to the side surface of the bipolar plate 1, and the inclined part extends into the common channel 13, and the ends of the two inclined parts are connected to each other.
[0061] An embodiment of the second aspect of the present invention is to provide a fuel cell. The fuel cell provided by the embodiment of the second aspect of the present invention includes the above-mentioned anti-corrosion protection structure for the common channel of the bipolar plate.
[0062] The fuel cell provided by the second aspect of the present invention has the anti-corrosion protection structure for the common channel of the bipolar plate provided by the embodiment of the first aspect of the present invention, and thus has all the beneficial effects of the anti-corrosion protection structure for the common channel of the bipolar plate provided by the embodiment of the first aspect of the present invention.
[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A corrosion protection structure for the common channel of a bipolar plate, characterized in that It includes a bipolar plate (1), a first protective strip (2) and a second protective strip (3); The bipolar plate (1) has a first side surface (11) and a second side surface (12) which are oppositely arranged, and the bipolar plate (1) is provided with a common channel (13) penetrating through the first side surface (11) and the second side surface (12); The first protective strip (2) is located on the first side surface (11), the second protective strip (3) is located on the second side surface (12) and is oppositely arranged with the first protective strip (2), and both the first protective strip (2) and the second protective strip (3) extend into the common channel (13) or respectively extend to both ends of the common channel (13) to block the direct scouring of the fluid on the side surface of the common channel (13).
2. The anti-corrosion protection structure for the bipolar plate common channel according to claim 1, characterized in that The first protective strip (2) and the membrane electrode (4) on one side of the bipolar plate (1) adopt an integral structure, and the second protective strip (3) and the membrane electrode (4) on the other side of the bipolar plate (1) adopt an integral structure.
3. The anti-corrosion protection structure for the bipolar plate common channel according to claim 2, wherein, When the first protective strip (2) and the second protective strip (3) respectively extend to both ends of the common channel (13), the extending directions of the first protective strip (2) and the second protective strip (3) are parallel to the bipolar plate (1).
4. The anti-corrosion protection structure for the bipolar plate common channel according to claim 2, characterized in that When both the first protective strip (2) and the second protective strip (3) extend into the common channel (13), the ends of the first protective strip (2) and the second protective strip (3) extending into the common channel (13) are hermetically connected.
5. The anti-corrosion protection structure for the bipolar plate common channel according to claim 4, characterized in that, The common channel (13) has a plurality of side surfaces connected in sequence, at least one side surface is an air inlet and water inlet surface (14), and the first protective strip (2) and the second protective strip (3) are not provided at both ends of the air inlet and water inlet surface (14) along the depth direction of the common channel (13).
6. The anti-corrosion protection structure for the bipolar plate common channel according to claim 5, characterized in that, The air inlet and water inlet surface (14) is covered with a protective layer, and the material of the protective layer is polyvinylidene fluoride.
7. The anti-corrosion protection structure for the bipolar plate common channel according to claim 1, wherein The first protective strip (2) and the gasket (5) on one side of the bipolar plate (1) adopt an integral structure, and the second protective strip (3) and the gasket (5) on the other side of the bipolar plate (1) adopt an integral structure.
8. The anti-corrosion protection structure for the bipolar plate common channel according to claim 1, characterized in that, Both the first protective strip (2) and the second protective strip (3) are independently arranged from the membrane electrodes (4) and gaskets (5) on both sides of the bipolar plate (1).
9. The anti-corrosion protection structure for the bipolar plate common channel according to claim 8, wherein, Both the first protective strip (2) and the second protective strip (3) extend into the common channel (13), and the ends extending into the common channel (13) are hermetically connected, and the first protective strip (2) and the second protective strip (3) adopt an integral structure.
10. A fuel cell, characterized in that, It includes the anti-corrosion protection structure for the common channel of the bipolar plate according to any one of claims 1 - 9.