Bipolar plate and preparation method thereof

Abstract

The invention relates to a bipolar plate and a preparation method thereof, the bipolar plate comprises a cathode plate and an anode plate, a first gasket and a second gasket are superposed between the cathode plate and the anode plate, one surface of the first gasket and one surface of the second gasket are both provided with array-type protrusions, and the surfaces of the first gasket and the second gasket with the protrusions are arranged in a staggered manner. The faces without protrusions are connected with the negative plate and the positive plate respectively, and a plurality of cooling liquid flow channels can be formed after the protrusions of the first gasket and the second gasket make contact in a staggered mode. A flow channel groove structure for cooling liquid to flow can be directly formed between the convex structures which are matched in a staggered mode, the structure is simple and convenient, on the other hand, a point-line contact mode generated between the convex structures has high mechanical performance under the pressed condition, deformation is not prone to occurring, and the service life is long. Therefore, the overall mechanical strength of the bipolar plate can be effectively improved while the bipolar plate structure is provided with the cooling liquid flow channel grooves, effective support can be provided in the process of assembling the bipolar plate into a pile, and the deformation phenomenon is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a bipolar plate and a method for preparing the same. Background Art

[0002] A fuel cell stack is composed of multiple fuel cell cells stacked in series. The bipolar plates and membrane electrode MEAs are alternately stacked, and seals are embedded between the cells. After the front and rear plates are pressed together, they are fastened with screws to form a fuel cell stack. The fuel cell stack is the place where electrochemical reactions occur and is the core part of the fuel cell system (or fuel cell engine). When the stack is working, hydrogen and oxygen are distributed to the bipolar plates of each single cell through the main gas channel of the stack, and are evenly distributed to the electrodes through the bipolar plate guide, and the electrochemical reaction is carried out through the electrode support and contact with the catalyst.

[0003] A fuel cell is essentially an open energy conversion device that produces electricity, heat, and water. Its working method is similar to that of an internal combustion engine, and its working principle is similar to that of a chemical power source. While generating electricity, the PEMFC stack will emit a large amount of heat energy. Therefore, a reasonable heat dissipation design must be used to maintain the normal operating temperature. Otherwise, the internal temperature of the stack will be too high, causing the stack to fail or even explode. In order to solve the problem of uniform cooling inside the stack during operation, the patent CN 107546393A discloses a proton exchange membrane fuel cell bipolar plate structure, which is formed by stacking an anode plate and a cathode plate, wherein a hydrogen flow field is provided on the front of the anode plate; an air flow channel is provided on the front of the cathode plate, and the air flow channel is composed of a plurality of air flow channel grooves; a coolant flow channel is provided on the back of the cathode plate, and the coolant flow channel is composed of a plurality of coolant flow channel grooves. Air and liquid flow channels are opened on the back of the bipolar plate. The patent uses a bipolar plate that integrates air cooling and liquid cooling, has a dual cooling function, simplifies the auxiliary cooling system, and improves the uniformity of temperature distribution in the stack; however, since the bipolar plate itself is relatively thin and a flow field is opened on the front, on this basis, opening other flow channels on the back further leads to a reduction in the mechanical strength of the bipolar plate. In the assembly of the stack, a single cell formed by N bipolar plates and membrane electrodes is stacked together, and then placed between two end plates, and finally mechanically locked by tightening with an internal positioning screw or a clamping strip. In this process, the overdeveloped bipolar plate is likely to be broken / deformed. Summary of the invention

[0004] In response to the technical problems raised above, a bipolar plate having a cooling function and strong stacking strength and a preparation method thereof are provided.

[0005] The technical means adopted by the present invention are as follows:

[0006] A bipolar plate comprises a cathode plate and an anode plate, wherein a first gasket and a second gasket are stacked between the cathode plate and the anode plate, wherein array-type protrusions are provided on one surface of the first gasket and the second gasket, wherein the first gasket and the second gasket are arranged alternately with each other on the sides containing protrusions, and the sides without protrusions are connected to the cathode plate and the anode plate respectively, and the protrusions of the first gasket and the second gasket can form a plurality of cooling liquid flow channels after being staggered in contact.

[0007] Furthermore, the array-type protrusions are all protrusions of the same specification, and the cross-section of the protrusions is semicircular.

[0008] Furthermore, the specifications of the coolant channels are the same.

[0009] Furthermore, the diameter of the protrusion is 0.1-1 mm, and the thickness of the first gasket and the second gasket are both 0.3-1 mm.

[0010] Furthermore, the material of the first gasket and the second gasket is one of a conductive polymer and a titanium plate.

[0011] Furthermore, the material of the protrusion is one of aluminum alloy, titanium alloy and nickel alloy.

[0012] The present invention also discloses a method for preparing the bipolar plate, comprising the following steps:

[0013] S1. Prepare cathode plates and anode plates by stamping;

[0014] S2. Grind one side of the first gasket and the second gasket to a roughness of Ra 40-Ra70 after grinding;

[0015] S3, using a 3D printer to evenly form a plurality of array-arranged convex structures with semicircular cross-sections on the other side of the first gasket and the second gasket;

[0016] S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, to form a cathode assembly and an anode assembly, respectively;

[0017] S5, stacking and installing the cathode assembly and anode assembly of S4 and S5, and making the protruding structures of the first gasket and the second gasket overlap each other, and then welding is used to achieve fixed connection between the cathode assembly and the anode assembly.

[0018] Furthermore, in S3, the 3D printing power is 200-350W; the laser nozzle printing linear speed is 500-800mm / s; the laser nozzle printing corner speed is 100-300mm / s; the laser nozzle printing empty running speed is 300-600mm / s; the laser track spacing is 0.1-0.15mm; the powder spreading speed is 10-40mm / s; and the printing layer thickness is 20-50μm.

[0019] Furthermore, in S4, welding is used to achieve fixed connection between the first gasket and the cathode plate, and between the second gasket and the anode plate, and the welding parameters are: welding power is 300-500W, and shielding gas is argon.

[0020] Furthermore, in S5, the welding parameters are: welding power is 200-350W, and shielding gas is argon.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention provides two gaskets between the anode plate and the cathode plate, and the gaskets are provided with interlaced protrusion structures. On the one hand, after the gaskets, the cathode plate and the anode plate are stacked, the interlaced protrusion structures can directly form a flow channel structure for the coolant to flow, and the structure is simple and convenient. On the other hand, the point-line contact generated between the protrusion structures has strong mechanical properties under pressure and is not easy to deform. Therefore, the bipolar plate structure can have a coolant flow channel and can effectively improve the mechanical strength of the bipolar plate as a whole, and can provide effective support in the process of assembling the bipolar plate into a stack, reducing deformation.

[0023] 2. In the specific preparation process, the protruding structure is formed on the first gasket and the second gasket by 3D printing, which has the advantage of one-piece molding, thereby effectively ensuring the uniformity of the entire protruding structure, and further ensuring the overall mechanical strength of the overall structure of the bipolar plate when stacked and compressed.

[0024] 3. With regard to the structure of the first gasket and the second gasket and their installation in the bipolar plate, the present invention designs the surfaces of the first gasket and the second gasket to have a certain roughness of Ra 40-Ra70, that is, the surfaces of the first gasket and the second gasket are friction surfaces with a certain granularity. In this state, the first gasket and the second gasket are not easy to slip during the stacking process with the anode plate and the cathode plate, which is beneficial to the positioning between the layers. Furthermore, under the action of external force, the rough surface is not easy to be displaced, which is more beneficial to the staggered matching of the raised structures on the first gasket and the second gasket and the structural stability of the coolant flow channel groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a schematic diagram of the structure of the present invention.

[0027] In the figure: 1. first gasket; 2. second gasket; 3. first gasket protrusion; 4. second gasket protrusion; 5. coolant flow channel; 6. cathode plate; 7. anode plate. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0032] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0033] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0034] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0035] like Figure 1As shown, an embodiment of the present invention discloses a bipolar plate, including a cathode plate and an anode plate, wherein a first gasket 1 and a second gasket 2 are stacked between the cathode plate 6 and the anode plate 7, and an array of first gasket protrusions 3 and second gasket protrusions 4 are respectively provided on one surface of the first gasket and the second gasket, the first gasket and the second gasket have a side containing protrusions that are staggered with each other, and a side without protrusions is connected to the cathode plate and the anode plate respectively, and the protrusions of the first gasket and the second gasket can form a plurality of coolant flow channels 5 after staggered contact.

[0036] Furthermore, the array-type protrusions are all protrusions of the same specification, and the cross-section of the protrusions is semicircular.

[0037] Furthermore, the specifications of each coolant flow channel are the same. In this embodiment, the shape of the coolant flow channel is a quasi-triangle with three sides all concave inward. Due to the misaligned placement, the first gasket protrusion or the second gasket protrusion at the end is not a complete semicircle, so the flow channel formed there is also not a quasi-triangle with the same specifications as above.

[0038] Furthermore, the diameter of the protrusion is 0.1-1 mm, and the thickness of the first gasket and the second gasket are both 0.3-1 mm.

[0039] Furthermore, the material of the first gasket and the second gasket is one of a conductive polymer and a titanium plate.

[0040] Furthermore, the material of the protrusion is one of aluminum alloy, titanium alloy and nickel alloy.

[0041] The present invention also discloses a method for preparing the bipolar plate, comprising the following steps:

[0042] S1. Prepare cathode plates and anode plates by stamping;

[0043] S2. Grind one side of the first gasket and the second gasket to a roughness of Ra 40-Ra70 after grinding;

[0044] S3, using a 3D printer to evenly form a plurality of array-arranged convex structures with semicircular cross-sections on the other side of the first gasket and the second gasket;

[0045] S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, to form a cathode assembly and an anode assembly, respectively;

[0046] S5, stacking and installing the cathode assembly and anode assembly of S4 and S5, and making the protruding structures of the first gasket and the second gasket overlap each other, and then welding is used to achieve fixed connection between the cathode assembly and the anode assembly.

[0047] Furthermore, in S3, the 3D printing power is 200-350W; the laser nozzle printing linear speed is 500-800mm / s; the laser nozzle printing corner speed is 100-300mm / s; the laser nozzle printing empty running speed is 300-600mm / s; the laser track spacing is 0.1-0.15mm; the powder spreading speed is 10-40mm / s; and the printing layer thickness is 20-50μm.

[0048] Furthermore, in S4, welding is used to achieve fixed connection between the first gasket and the cathode plate, and between the second gasket and the anode plate, and the welding parameters are: welding power is 300-500W, and shielding gas is argon.

[0049] Furthermore, in S5, the welding parameters are: welding power is 200-350W, and shielding gas is argon.

[0050] Example 1

[0051] This embodiment discloses a method for preparing the above-mentioned bipolar plate, and the specific steps are as follows:

[0052] S1. Prepare cathode plates and anode plates with a thickness of 2 mm by stamping;

[0053] S2. A first gasket and a second gasket are made of titanium material and each has a thickness of 1 mm. One side of the first gasket and the second gasket is polished with sandpaper or sandblasted to increase the surface roughness of the first gasket and the second gasket. The roughness of the polished first gasket and the second gasket is Ra 50.

[0054] S3, titanium alloy powder is loaded into the 3D printer, and the first gasket and the second gasket are placed on the printing platform of the 3D printer. The 3D printer evenly forms a plurality of array-arranged semicircular convex structures on the other side of the first gasket and the second gasket, and the diameter of the convex structure is 0.5 mm;

[0055] The parameters of 3D printing include: power of 350W; laser nozzle printing linear speed of 800mm / s; laser nozzle printing corner speed of 300mm / s; laser nozzle printing empty running speed of 300mm / s; laser track spacing of 0.15mm; powder spreading speed of 40mm / s; printing layer thickness of 50μm;

[0056] S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, and realizing the fixed connection between the first gasket and the cathode plate, and the second gasket and the anode plate by welding, to form a cathode assembly and an anode assembly respectively, wherein the welding power is 500W, and the shielding gas is helium;

[0057] S5. Install the cathode and anode assemblies of S4 and S5 in layers, and stack the raised structures of the first gasket and the second gasket alternately, and then use welding to achieve fixed connection between the cathode and anode assemblies. The welding power is 350w and the shielding gas is argon.

[0058] Example 2

[0059] This embodiment discloses a method for preparing the above-mentioned bipolar plate, and the specific steps are as follows:

[0060] S1. Prepare cathode plates and anode plates with a thickness of 2 mm by stamping;

[0061] S2. Use polyaniline to make a first gasket and a second gasket with a thickness of 1 mm. Use sandpaper grinding or sandblasting on one side of the first gasket and the second gasket to increase the surface roughness of the first gasket and the second gasket. The roughness of the first gasket and the second gasket after grinding is Ra70.

[0062] S3, using aluminum alloy powder to load into the 3D printer, placing the first gasket and the second gasket on the printing platform of the 3D printer, and the 3D printer evenly forms a plurality of array-arranged semicircular cross-section convex structures on the other side of the first gasket and the second gasket, and the diameter of the convex structure is 0.8 mm;

[0063] The parameters of 3D printing include: power of 250W; laser nozzle printing linear speed of 600mm / s; laser nozzle printing corner speed of 200mm / s; laser nozzle printing empty running speed of 400mm / s; laser track spacing of 0.1mm; powder spreading speed of 10mm / s; printing layer thickness of 20μm;

[0064] S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, and realizing the fixed connection between the first gasket and the cathode plate, and the second gasket and the anode plate by welding, to form a cathode assembly and an anode assembly respectively, wherein the welding power is 400W, and the shielding gas is helium;

[0065] S5. Install the cathode and anode assemblies of S4 and S5 in layers, and stack the raised structures of the first gasket and the second gasket alternately, and then use welding to achieve fixed connection between the cathode and anode assemblies. The welding power is 350w and the shielding gas is argon.

[0066] Example 3

[0067] This embodiment discloses a method for preparing the above-mentioned bipolar plate, and the specific steps are as follows:

[0068] S1. A cathode plate and an anode plate with a thickness of 1.5 mm are prepared by stamping;

[0069] S2. Use polycarbazole to make a first gasket and a second gasket each with a thickness of 0.8 mm. Use sandpaper grinding or sandblasting on one side of the first gasket and the second gasket to increase the surface roughness of the first gasket and the second gasket. The roughness of the first gasket and the second gasket after grinding is Ra40.

[0070] S3, using aluminum alloy powder to load into the 3D printer, placing the first gasket and the second gasket on the printing platform of the 3D printer, and the 3D printer evenly forms a plurality of array-arranged semicircular cross-section convex structures on the other side of the first gasket and the second gasket, and the diameter of the convex structure is 0.8 mm;

[0071] The parameters of 3D printing include: power of 200W; laser nozzle printing line speed of 650mm / s; laser nozzle printing corner speed of 150mm / s; laser nozzle printing empty running speed of 550mm / s; laser track spacing of 0.12mm; powder spreading speed of 25mm / s; printing layer thickness of 35μm;

[0072] S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, and realizing the fixed connection between the first gasket and the cathode plate, and the second gasket and the anode plate by welding, to form a cathode assembly and an anode assembly respectively, wherein the welding power is 400W, and the shielding gas is helium;

[0073] S5. Install the cathode and anode assemblies of S4 and S5 in layers, and stack the raised structures of the first gasket and the second gasket alternately, and then use welding to achieve fixed connection between the cathode and anode assemblies. The welding power is 250w and the shielding gas is argon.

[0074] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bipolar plate, characterized in that: It includes a cathode plate and an anode plate, wherein a first gasket and a second gasket are stacked between the cathode plate and the anode plate, and array protrusions are provided on one surface of the first gasket and the second gasket, and the first gasket and the second gasket have sides with protrusions staggered with each other, and sides without protrusions are connected to the cathode plate and the anode plate respectively, and the protrusions of the first gasket and the second gasket can form a plurality of cooling liquid flow channels after staggered contact.

2. The bipolar plate according to claim 1, characterized in that: The array-type protrusions are all protrusions of the same specification, and the cross-section of the protrusions is semicircular.

3. The bipolar plate according to claim 1, characterized in that: The specifications of each coolant flow channel are the same.

4. The bipolar plate according to claim 1, characterized in that: The diameter of the protrusion is 0.1-1 mm, and the thickness of the first gasket and the second gasket are both 0.3-1 mm.

5. The bipolar plate according to claim 1, characterized in that: The material of the first gasket and the second gasket is one of a conductive polymer and a titanium plate.

6. The bipolar plate according to claim 1, characterized in that: The material of the protrusion is one of aluminum alloy, titanium alloy and nickel alloy.

7. A method for preparing a bipolar plate according to any one of claims 1 to 6, characterized in that: The steps include: S1. Prepare cathode plates and anode plates by stamping; S2. Grind one side of the first gasket and the second gasket to a roughness of Ra 40-Ra70 after grinding; S3, using a 3D printer to evenly form a plurality of array-arranged convex structures with semicircular cross-sections on the other side of the first gasket and the second gasket; S4, connecting the side of the first gasket and the second gasket of S3 without the protruding structure to the side of the cathode plate and the anode plate without the flow field structure, respectively, to form a cathode assembly and an anode assembly, respectively; S5, stacking and installing the cathode assembly and anode assembly of S4 and S5, and making the protruding structures of the first gasket and the second gasket overlap each other, and then welding is used to achieve fixed connection between the cathode assembly and the anode assembly.

8. The method according to claim 7, characterized in that In S3, the 3D printing power is 200-350W; the laser nozzle printing linear speed is 500-800mm / s; the laser nozzle printing corner speed is 100-300mm / s; the laser nozzle printing empty running speed is 300-600mm / s; the laser track spacing is 0.1-0.15mm; the powder spreading speed is 10-40mm / s; the printing layer thickness is 20-50μm.

9. The method according to claim 7, characterized in that: In S4, welding is used to achieve fixed connection between the first gasket and the cathode plate, and between the second gasket and the anode plate. The welding parameters are: welding power is 300-500W, and the shielding gas is argon.

10. The method according to claim 7, characterized in that In S5, the welding parameters are: welding power is 200-350W, and the shielding gas is argon.

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