Cathode plate, single cell, and fuel cell

Abstract

The application provides a cathode plate, a single battery and a fuel cell. The cathode plate comprises a body, the body having a first side surface; a water outlet manifold hole is arranged on the body; the water outlet manifold hole comprises a first hole section and a second hole section which are sequentially arranged along the thickness direction of the body; the cross-sectional area of the first hole section is greater than that of the second hole section; the first hole section has an inlet of the water outlet manifold hole, and the inlet is arranged on the first side surface; a hydrophobic coating is arranged on the first side surface and extends to the joint of the first hole section and the first side surface; and a hydrophilic coating is arranged on the hole wall of the first hole section and extends to the joint of the first hole section and the first side surface. The application aims to solve the technical problem that the cathode water is easy to damage the sealing structure in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a cathode plate, a single battery and a fuel cell. BACKGROUND

[0002] There are various types of fuel cells. Proton exchange membrane fuel cell is a high-efficiency energy conversion power generation device which uses hydrogen as the best fuel and converts chemical energy in fuel and oxidant into electrical energy in an electrochemical reaction. It does not pass through the heat engine process and is not limited by the Carnot cycle, and the actual energy conversion efficiency is as high as 50% to 80%. Proton exchange membrane fuel cell is the fifth generation fuel cell developed after alkaline fuel cell, phosphoric acid fuel cell, molten carbonate fuel cell and solid oxide fuel cell. It has the advantages of no pollution, fast start, long service life, high specific power and specific energy, low working temperature, etc., and is recognized as the ideal power source for replacing internal combustion engine to become new energy vehicle, and can be developed into various portable power sources and distributed independent power sources, and has a very wide market.

[0003] Proton exchange membrane fuel cell mainly includes membrane electrode and cathode plate and anode plate located on both sides of the membrane electrode. Among them, the flow guide hole and the flow field on the cathode plate provide air as the oxidant on the other side of the MEA assembly. In the cathode, the oxygen in the air is catalytically reacted to obtain electrons to form negative ions, which react with the migrated protons to generate water. The generated water is discharged from the fuel cell through the water outlet manifold. The water outlet manifold is defined by the stacked manifold holes on the cathode plate, the anode plate and the membrane electrode. At the manifold, the polar plate needs to be strictly sealed. However, since the cathode product includes liquid water, the liquid water is prone to freeze at low temperature. After the liquid water freezes, the volume expands, which may damage the sealing structure and cause sealing failure. SUMMARY

[0004] The present application provides a cathode plate, a single battery and a fuel cell, which aims to solve the technical problem that the cathode water product easily damages the sealing structure in the prior art.

[0005] The present application provides a cathode plate, which comprises:

[0006] A body, the body has a first side surface; the body is provided with a water outlet manifold hole; the water outlet manifold hole comprises a first hole section and a second hole section which are sequentially distributed along the thickness direction of the body; the cross-sectional area of the first hole section is greater than that of the second hole section; the first hole section has an inlet of the water outlet manifold hole, and the inlet is arranged on the first side surface;

[0007] A hydrophobic coating, the hydrophobic coating is arranged on the first side surface and extends to the intersection of the first hole section and the first side surface; and

[0008] A hydrophilic coating is disposed on a hole wall of the first hole section and extends to an intersection of the first hole section and the first side surface.

[0009] Optionally, the first hole section includes a first hole wall extending in a thickness direction of the body and a second hole wall extending in a lateral direction of the body, the second hole wall having a lateral width greater than a depth of the first hole wall.

[0010] Optionally, the first side surface has a first junction section at the inlet, and the first hole section has a second junction section at the inlet, the first and second junction sections being transitionally connected.

[0011] Optionally, a center of curvature of the first junction section is located inside the body, and a center of curvature of the second junction section is located outside the body.

[0012] Optionally, the first and second junction sections have the same bending radius.

[0013] Optionally, the cathode plate further has a second side surface disposed opposite to the first side surface, the second hole section has an outlet of the water outlet manifold hole, and the outlet is disposed on the second side surface.

[0014] The application further provides a single cell, which comprises:

[0015] an anode plate;

[0016] a membrane electrode; and

[0017] a cathode plate as described above; the membrane electrode is disposed on the first side surface, the anode plate is disposed on a side of the membrane electrode away from the cathode plate; a sealing structure is provided between the membrane electrode and the cathode plate, the sealing structure is disposed around an inlet of the first hole section and has a spacing in a lateral direction of the body from the inlet of the first hole section.

[0018] Optionally, a depth of the first hole section is greater than the spacing.

[0019] Optionally, the depth of the first hole section is greater than a thickness of the sealing structure.

[0020] The application further provides a fuel cell, which comprises a single cell as described above.

[0021] When the cathode plate of the application is used for a fuel cell, the first side of the body of the cathode plate faces the membrane electrode assembly, and the first side and the membrane electrode assembly form an oxygen (air) channel. The body is provided with a water outlet manifold hole, and the water outlet manifold hole forms a water outlet manifold. The first hole section has an inlet of the water outlet manifold hole, which is arranged on the first side to communicate the oxygen (air) channel and the water outlet manifold, and to discharge the cathode water into the water outlet manifold. The water outlet manifold hole comprises a first hole section and a second hole section arranged in sequence along the thickness direction of the body, the cross-sectional area of the first hole section is larger than that of the second hole section, so that there is a transition step between the first hole section and the second hole section. A hydrophobic coating is arranged on the first side, and the hydrophobic coating extends to the inlet of the first hole section, so that the water flowing into the first side will not accumulate at the gap and flow into the water outlet manifold hole. A hydrophilic coating is arranged on the hole wall of the first hole section, so that the water accumulates at the first hole wall, and due to the transition step between the first hole section and the second hole section, the water gradually accumulates at this position, thereby forming a water seal, improving the sealing effect, and avoiding water leakage. Moreover, the water seal can effectively prevent the water from entering the gap defined by the sealing structure, the cathode plate and the membrane electrode assembly, thereby avoiding the water freezing and expanding at low temperature to damage the sealing structure, and improving the sealing effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative effort.

[0023] Figure 1 is a structural schematic diagram of the cathode plate provided by the embodiment of the application;

[0024] Figure 2 is another structural schematic diagram of the cathode plate provided by the embodiment of the application;

[0025] Figure 3 is Figure 2 is a local enlarged view of A in FIG. 4;

[0026] Figure 4 is another structural schematic diagram of the cathode plate provided by the embodiment of the application;

[0027] Figure 5 is Figure 4 is a local enlarged view of B in FIG. 5;

[0028] Figure 6 is a top view structural schematic diagram of the cathode plate provided by the embodiment of the application;

[0029] Figure 7is a structural schematic diagram of a cathode plate of an embodiment of the present application when used in a single battery.

[0030] List of reference signs

[0031]

[0032] DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "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 purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0035] In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation described as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. The following description is presented to enable any person skilled in the art to make and use the application. In the following description, for purposes of explanation, specific details are set forth. It is apparent to those skilled in the art that the present application can be practiced without using these specific details. In other instances, well-known structures and processes are not described in detail in order to avoid obscuring the description of the present application. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features presented herein.

[0036] A proton exchange membrane fuel cell includes a plurality of cell monomers stacked together. Each cell monomer includes a cathode plate, a membrane electrode, and an anode plate. The cathode plate, the membrane electrode, and the anode plate define a water outlet manifold. An oxygen (air) channel is defined between the cathode plate and the membrane electrode, and the water outlet manifold is in communication with the oxygen (air) channel to discharge water produced in the oxygen (air) channel. In order to avoid water leakage, the cathode plate and the membrane electrode are provided with a sealing structure at the water outlet manifold. Due to the process, the sealing structure is not provided at the inlet edge of the water outlet manifold, but maintains a gap with the inlet edge; therefore, a part of the water produced will invade the gap. Liquid water is prone to freezing at low temperature; after the liquid water freezes, the volume expands, which may damage the sealing structure and cause sealing failure. Embodiments of the present application provide a cathode plate to solve the technical problem.

[0037] Specifically, as shown in Figure 1 and Figure 6 embodiments of the present application provide a cathode plate 100, which includes:

[0038] a body 110, the body 110 having a first side 111; the body 110 is provided with a water outlet manifold hole S; the water outlet manifold hole S includes a first hole section S1 and a second hole section S2 distributed in the thickness direction of the body 110 in sequence; the cross-sectional area of the first hole section S1 is greater than that of the second hole section S2; the first hole section S1 has an inlet O1 of the water outlet manifold hole S, and the inlet O1 is arranged on the first side 111;

[0039] a hydrophobic coating 120 arranged on the first side 111 and extending to the intersection of the first hole section S1 and the first side 111; and

[0040] a hydrophilic coating 130 arranged on the hole wall of the first hole section S1 and extending to the intersection of the first hole section S1 and the first side 111.

[0041] When the cathode plate 100 of the present application is used in a fuel cell, the first side 111 of the body 110 of the cathode plate 100 faces the membrane electrode 200, and the first side 111 and the membrane electrode 200 form an oxygen (air) channel. The body 110 is provided with a water outlet manifold hole S, which forms a water outlet manifold. The first hole section S1 has the inlet O1 of the water outlet manifold hole S, which is arranged on the first side 111 to communicate the oxygen (air) channel and the water outlet manifold, and to discharge the cathode water into the water outlet manifold. The water outlet manifold hole S includes the first hole section S1 and the second hole section S2 arranged in sequence along the thickness direction of the body 110, and the cross-sectional area of the first hole section S1 is greater than that of the second hole section S2, so that there is a transition step between the first hole section S1 and the second hole section S2. In combination Figure 7 As shown, the hydrophobic coating 120 is arranged on the first side 111 and extends to the intersection of the first hole section S1 and the first side 111, so that the water flowing into the first side 111 does not accumulate at the gap and flows into the water outlet manifold hole S. The hydrophilic coating 130 is arranged on the hole wall of the first hole section S1, so that the water accumulates at the first hole wall S1-1 and gradually accumulates at the transition step between the first hole section S1 and the second hole section S2, thereby forming a water seal W and improving the sealing effect to prevent water leakage. Moreover, the water seal W can effectively prevent water from entering the gap defined by the sealing structure 300, the cathode plate 100 and the membrane electrode 200, thereby preventing the water from freezing and expanding at low temperature to damage the sealing structure 300, and improving the sealing effect.

[0042] In some embodiments, the material in the hydrophobic coating 120 generally includes one of methyltrimethoxysilane, trifluoropropyltrimethoxysilane or trimethylchlorosilane. The hydrophilic coating 130 contains a hydrophilic functional group, which includes but is not limited to C N, C OH or C H.

[0043] As an optional implementation of the above embodiment, as Figure 1As shown, the first hole section S1 includes a first hole wall S1-1 extending along the thickness direction of the body 110 and a second hole wall S1-2 extending along the transverse direction of the body 110, the transverse width L1 of the second hole wall S1-2 being greater than the depth H1 of the first hole wall S1-1. In embodiments, the second hole wall S1-2 is a transition step between the first hole section S1 and the second hole section S2. The transverse direction is perpendicular to the thickness direction of the body 110, and is parallel to the plane defined by the length direction and the width direction of the body 110. The transverse width of the second hole wall S1-2 can be understood as the difference between the radius of the first hole section S1 and the radius of the second hole section S2. By setting the transverse width of the second hole wall S1-2 to be greater than the depth of the first hole wall S1-1, water production can form water droplets in the first hole section S1, and the water droplets can emerge from the inlet O1 to effectively block the water production from entering the gap defined by the sealing structure 300, the cathode plate 100 and the membrane electrode 200.

[0044] As optional implementations of the above embodiments, as shown in Figure 2 and Figure 3 , as shown in Figure 4 and Figure 5 , the first side surface 111 has a first joint section 111a located at the inlet, the first hole section S1 has a second joint section S1-1a located at the inlet, and the first joint section 111a and the second joint section S1-1a are transitionally connected; wherein the first joint section 111a and the second joint section S1-1a are curved sections. In embodiments, the first joint section and the second joint section are curved to facilitate the water production on the first side surface 111 to enter the water outlet manifold hole S. Generally, the first joint section 111a and the second joint section S1-1a can be circular arc sections, elliptical arc sections or other curved sections. In embodiments, the first joint section 111a is provided with a hydrophobic coating 120, and the second joint section S1-1a is provided with a hydrophilic coating 130.

[0045] In some embodiments, as shown in Figure 3 , the first joint section 111a and the second joint section S1-1a are curved in the same direction and both curved towards the outside of the body 110, and both are concentric and have the same radius. In some embodiments, the first joint section 111a and the second joint section S1-1a are curved in the same direction and both curved towards the outside of the body 110, and both are concentric but have different radii.

[0046] In some other embodiments, as shown in Figure 5As shown, the arc center of the first joint segment 111a is located inside the body 110, and the arc center of the second joint segment S1-1a is located outside the body 110. In an embodiment, the first joint segment 111a is curved towards the outside of the body 110, and the second joint segment S1-1a is curved towards the inside of the body 110. In this structure, water production is more likely to directly drip on the second hole wall S1-2 in the form of small water droplets from the joint between the first joint segment 111a and the second joint segment S1-1a on the hydrophobic coating 120, and gradually accumulate on the second hole wall S1-2 to grow into larger water droplets to form a water seal W.

[0047] As an optional implementation of the above embodiment, as shown in Figure 1 As shown, the cathode plate 100 also has a second side 112 opposite to the first side 111, and the second hole segment S2 has an outlet O2 of the water outlet manifold hole S, which is arranged on the second side 112. It should be noted that in one battery monomer, the anode plate and the membrane electrode 200 are both provided with a water outlet manifold hole. After the formation of a monomer battery, the water outlet manifold holes on the anode plate and the membrane electrode 200 and the water outlet manifold hole S on the cathode plate 100 define a water outlet manifold unit channel. After a plurality of battery monomers form a fuel cell, the water outlet manifold unit channel constructs a water outlet manifold. In an embodiment, the second side 112 faces the anode plate of the adjacent another monomer battery. The anode plate is provided with a water outlet manifold hole, which is in sealing communication with the water outlet manifold hole S. The water produced in one battery monomer enters the water outlet manifold unit channel of the adjacent battery monomer through the outlet O2 on the second side 112, and then flows out of the fuel cell.

[0048] The application also provides a monomer battery, which comprises an anode plate (not shown), a membrane electrode 200 and a cathode plate 100. In an embodiment, the anode plate and the cathode plate 100 are respectively attached to opposite sides of the membrane electrode 200. The anode plate and the membrane electrode 200 define a hydrogen channel. The cathode plate 100 and the membrane electrode 200 define an oxygen (air) channel. Among them, the anode plate is provided with a hydrogen manifold hole, which is in communication with the hydrogen channel. The cathode plate 100 is provided with an oxygen (air) manifold hole, which is in communication with the oxygen (air) channel. The cathode plate 100 is also provided with a water outlet manifold hole S, which is in communication with the oxygen (air) channel, and the oxygen (air) manifold hole is arranged on the opposite sides of the oxygen (air) channel to discharge water from the monomer battery. At the anode, hydrogen is catalytically reacted to produce protons (hydrogen ions) and electrons, and the protons migrate to the cathode through the proton exchange membrane, while the electrons are led out to the external circuit through the plate, and the electrons flow through the external circuit to the cathode. At the cathode, the oxygen in the air is catalytically reacted to form negative ions by obtaining electrons, and reacts with the migrated protons to generate water. During the entire electrochemical reaction process, the current led out by the plate is the result of power generation of the fuel cell.

[0049] Specifically, in the embodiment, the membrane electrode 200 is arranged on the first side surface 111, and the anode plate is arranged on the side of the membrane electrode 200 away from the cathode plate 100; the sealing structure 300 is arranged between the membrane electrode 200 and the cathode plate 100, and the sealing structure 300 is arranged around the inlet O1 of the first hole section S1 and has a spacing in the transverse direction of the body 110 from the inlet O1 of the first hole section S1. The hydrophobic coating 120 is arranged on the first side surface 111 and extends to the inlet O1 of the first hole section S1, so that the water produced on the first side surface 111 does not accumulate at the gap and flows into the water outlet manifold hole S, and the hydrophilic coating 130 is arranged on the hole wall of the first hole section S1, so that the water produced accumulates at the first hole wall S1-1 and gradually accumulates at the transition step between the first hole section S1 and the second hole section S2, thereby forming a water seal W and improving the sealing effect to prevent water leakage. Moreover, since the sealing structure 300 is arranged around the inlet O1 of the first hole section S1 and has a spacing in the transverse direction of the body 110 from the inlet O1 of the first hole section S1, that is, the sealing structure 300, the cathode plate 100, and the membrane electrode 200 define a certain gap; the water seal W can effectively prevent the water produced from entering the gap defined by the sealing structure 300, the cathode plate 100, and the membrane electrode 200, thereby preventing the water produced from freezing and expanding to damage the sealing structure 300 in a low-temperature state, and improving the sealing effect.

[0050] It should be noted that the anode plate and the membrane electrode 200 each correspondingly have a water outlet manifold hole. After the single cell is formed, the water outlet manifold holes on the anode plate and the membrane electrode 200 and the water outlet manifold hole S on the cathode plate 100 define a water outlet manifold unit channel. After a plurality of cell monomers form a fuel cell, the water outlet manifold unit channels construct a water outlet manifold.

[0051] As an optional implementation of the above embodiment, the depth H1 of the first hole section S1 is greater than the spacing L2. In the embodiment, the sealing structure 300, the cathode plate 100, and the membrane electrode 200 define a certain gap, and the transverse dimension of the gap is the spacing. In the embodiment, the gap is small enough to be less than the depth of the first hole section S1, so as to facilitate the water produced flowing into the water outlet manifold hole S under the action of the hydrophobic coating 120 and being adsorbed by the hydrophilic coating 130 to form the water seal W.

[0052] As an optional implementation of the above embodiment, the depth H1 of the first hole section S1 is greater than the thickness H2 of the sealing structure 300. Since the thickness of the sealing structure 300 is less than the depth of the first hole section S1, the space between the sealing structure 300, the membrane electrode 200 and the cathode plate 100 is narrow. Under the effect of the hydrophobic coating 120, even if a part of the water production seeps or flows into the gap, it is difficult to accumulate in the narrow space.

[0053] The application also provides a fuel cell comprising a plurality of the above-mentioned single cells. The single cells adopt some or all of the technical solutions of the above-mentioned embodiments, so that the fuel cell stack has some or all of the technical advantages of the above-mentioned embodiments, which will not be repeated here. In the embodiments, it should be noted that the number of the single cells is specifically set according to actual needs, and is not specifically limited in the embodiments. The water outlet manifold unit channels of the single cells are constructed into a water outlet manifold after the single cells are stacked. The cathode water production in each single cell flows into the water outlet manifold and is discharged from the fuel cell.

[0054] The above describes in detail the cathode plate, the single cell and the fuel cell provided by the embodiments of the application. The principles and implementation manners of the application are described by using specific examples. The above description of the embodiments is only used to help understand the method of the application and its core idea. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the application. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. A cathode plate characterized by, Comprising: a body having a first side; the body is provided with a water outlet manifold hole; the water outlet manifold hole comprises a first hole section and a second hole section arranged in sequence along the thickness direction of the body; the cross-sectional area of the first hole section is greater than that of the second hole section; the first hole section has an inlet of the water outlet manifold hole, which is arranged on the first side; a hydrophobic coating arranged on the first side and extending to the junction of the first hole section and the first side; and a hydrophilic coating arranged on the hole wall of the first hole section and extending to the junction of the first hole section and the first side; wherein the first side has a first junction section at the inlet, the first hole section has a second junction section at the inlet, and the first and second junction sections are transitionally connected; wherein the first and second junction sections are both curved sections; the cathode plate further has a second side arranged opposite to the first side, the second hole section has an outlet of the water outlet manifold hole, which is arranged on the second side; the first hole section and the second hole section have a transition step therebetween, which is used to form a water seal.

2. The cathode plate of claim 1, wherein The first hole section comprises a first hole wall extending along the thickness direction of the body and a second hole wall extending along the lateral direction of the body, and the lateral width of the second hole wall is greater than the depth of the first hole wall.

3. The cathode plate of claim 1, wherein The center of curvature of the first junction section is located inside the body, and the center of curvature of the second junction section is located outside the body.

4. The cathode plate as claimed in claim 1 or 3, wherein The first junction section and the second junction section have the same bending radius.

5. A single cell characterized by, The monomer battery comprises: an anode plate; a membrane electrode; and the cathode plate of any one of claims 1 to 4; the membrane electrode is arranged on the first side, and the anode plate is arranged on the side of the membrane electrode away from the cathode plate; a sealing structure is arranged between the membrane electrode and the cathode plate, and the sealing structure is arranged around the inlet of the first hole section and has a spacing in the lateral direction of the body from the inlet of the first hole section.

6. The single-cell battery as described in claim 5, characterized in that, The depth of the first hole section is greater than the spacing.

7. The single-cell battery as described in claim 5, characterized in that, The depth of the first hole section is greater than the thickness of the sealing structure.

8. A fuel cell characterized by comprising: The monomer battery comprises a plurality of monomer batteries as claimed in any one of claims 5 to 7.

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