Cathode plate, bipolar plate and fuel cell of proton exchange membrane fuel cell

Abstract

The present invention relates to the technical field of fuel cells, and discloses a cathode plate, a bipolar plate and a fuel cell of a proton exchange membrane fuel cell, wherein the cathode plate comprises a cathode plate body, one end of the cathode plate body is provided with an oxidant inlet, and the other end of the cathode plate body is provided with an oxidant outlet; a cathode flow field formed by grooves is provided on one side surface of the cathode plate body; the cathode flow field comprises a first transition portion, a parallel flow field portion, a second transition portion and a serpentine flow field portion connected in sequence; the first transition portion is connected to the oxidant inlet, and the serpentine flow field portion is connected to the oxidant outlet. The present invention can improve the drainage effect of the cathode flow field without increasing the pressure of the cathode oxidant supply device, thereby ensuring that the oxidant can fully react, thereby improving the electrochemical reaction performance of the cathode.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a cathode plate, a bipolar plate and a fuel cell of a proton exchange membrane fuel cell. Background Art

[0002] The main function of the cathode flow field of a proton exchange membrane fuel cell is to transport the oxidant (air or oxygen) to the cathode surface for electrochemical reaction, while discharging the reaction product (water). When the proton exchange membrane fuel cell is working, a large amount of water will be produced at the cathode; if this water is not discharged in time, the oxidant will not be able to reach the reaction interface, thus causing mass transfer polarization, reducing battery performance, and even causing electrode reversal, burning the electrode, and causing irreversible damage. Therefore, a suitable flow field structure will optimize the drainage of the cathode and ensure the continuous and stable operation of the battery.

[0003] At present, the cathode flow field structures include point flow field, mesh flow field, parallel flow field, multi-channel serpentine flow field, and bionic flow field, among which the most widely used are parallel flow field and multi-channel serpentine flow field. Both flow fields have the advantage of no dead zone. By optimizing the flow field structure parameters, the oxidant (air or oxygen) can be effectively transported to the cathode for electrochemical reaction.

[0004] However, compared with the multi-channel serpentine flow field, the parallel flow field has the advantage of low resistance drop and lower requirements for the cathode oxidant supply equipment, but since the centerline velocity of the flow field is relatively small, the drainage effect is not as good as that of the multi-channel serpentine flow field; the centerline velocity of the multi-channel serpentine flow field is relatively large, and the resistance drop of the flow field is large, which makes the driving force for drainage of the flow field large. Therefore, the drainage effect of the multi-channel serpentine flow field is better than that of the parallel flow field, but the requirements for the cathode oxidant supply equipment are higher, and sufficient potential energy needs to be provided. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to improve the drainage effect of the cathode flow field without increasing the pressure of the cathode oxidant supply equipment and ensure that the oxidant fully reacts, thereby improving the electrochemical reaction performance of the cathode.

[0006] In order to solve the above technical problems, the first aspect of the present invention provides a cathode plate of a proton exchange membrane fuel cell, which includes a cathode plate body, one end of the cathode plate body is provided with an oxidant inlet, and the other end of the cathode plate body is provided with an oxidant outlet; a cathode flow field formed by grooves is provided on one side surface of the cathode plate body, the starting end of the cathode flow field is connected to the oxidant inlet, and the end of the cathode flow field is connected to the oxidant outlet;

[0007] The cathode flow field comprises a first transition portion, a parallel flow field portion, a second transition portion and a serpentine flow field portion connected in sequence; the first transition portion is connected to the oxidant inlet, and the serpentine flow field portion is connected to the oxidant outlet;

[0008] The parallel flow field portion includes a plurality of parallel distributed linear grooves, the starting end of each linear groove is connected to the first transition portion, and the end of each linear groove is connected to the second transition portion;

[0009] The serpentine flow field portion includes a plurality of serpentine grooves, the starting end of each of the serpentine grooves is connected to the second transition portion, and the end of each of the serpentine grooves is connected to the oxidant outlet.

[0010] Furthermore, the first transition section is located at the starting end of the parallel flow field section, and the second transition section is located at the end of the parallel flow field section; the oxidant inlet is connected to the right end of the first transition section, and the starting end of the serpentine flow field section is connected to the left end of the second transition section.

[0011] Furthermore, the end of each of the serpentine grooves is located on the left side of the cathode plate body, and the structures of each of the serpentine grooves are the same.

[0012] Furthermore, the number of the serpentine grooves is at least 2.

[0013] Furthermore, each of the serpentine grooves has at least two winding portions.

[0014] Furthermore, the cathode flow field also includes an inlet slot, and the oxidant inlet is connected to the first transition portion through the inlet slot.

[0015] Furthermore, a plurality of flow guiding pillars are respectively provided in the first transition portion and the second transition portion, and the flow guiding pillars are prismatic or cylindrical.

[0016] A second aspect of the present invention provides a bipolar plate for a proton exchange membrane fuel cell, comprising an anode plate and a cathode plate as described in any of the above schemes.

[0017] A third aspect of the present invention provides a proton exchange membrane fuel cell, which includes the bipolar plate described in the above solution.

[0018] The cathode plate, bipolar plate and fuel cell of a proton exchange membrane fuel cell provided by the above technical solution have the following beneficial effects compared with the prior art:

[0019] According to the characteristics of the cathode when the proton exchange membrane fuel cell is working, less water is generated and accumulated in the area near the oxidant inlet, and the drainage requirement here is low. The structure of setting the parallel flow field part will not affect the drainage effect and help reduce the resistance drop, reducing the performance requirements of the oxidant supply equipment; in the part near the oxidant outlet, more water is generated and accumulated, and the drainage requirement here is high. The serpentine flow field part structure helps to increase the cathode surface linear velocity, thereby increasing the resistance drop and drainage driving force, and improving the drainage effect. Therefore, the present invention can improve the drainage effect of the cathode flow field without increasing the pressure of the cathode oxidant supply equipment, and ensure that the oxidant fully reacts, thereby improving the electrochemical reaction performance of the cathode.

[0020] In addition, the first transition portion and the second transition portion respectively connect the two ends of each linear groove, so that each linear groove is connected to each other, and each linear groove is connected to the oxidant inlet and the serpentine flow field portion, ensuring the transition between the oxidant inlet and the parallel flow field portion, and between the parallel flow field portion and the serpentine flow field portion, so that the oxidant can smoothly transition between different flow field structures and flow evenly, so that the oxidant can fully react. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The cathode plate of the first embodiment of the present invention;

[0022] Figure 2 is the cathode plate of the second embodiment of the present invention;

[0023] Figure 3 This is the cathode plate of the third embodiment of the present invention.

[0024] Among them, 1 is cathode plate, 10 is cathode plate body, 11 is oxidant inlet, 12 is oxidant outlet, 13 is cathode flow field, 131 is first transition part, 132 is parallel flow field part, 133 is second transition part, 134 is serpentine flow field part, 135 is inlet groove, and 136 is flow guide support. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like used in the present invention to indicate the orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention 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 cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. In addition, the "starting end" refers to the end of the corresponding component where the oxidant enters, and the "end" refers to the end of the corresponding component where the oxidant flows out.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" 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 a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] Embodiment 1

[0029] like Figure 1 As shown, the present embodiment provides a cathode plate 1 of a proton exchange membrane fuel cell, wherein the cathode plate 1 comprises a cathode plate body 10, wherein one end of the cathode plate body 10 is provided with an oxidant inlet 11, and the other end of the cathode plate body 10 is provided with an oxidant outlet 12; a cathode flow field 13 formed by grooves is provided on one side surface of the cathode plate body 10, i.e., the front side in the figure; the starting end of the cathode flow field 13 is connected to the oxidant inlet 11, and the end of the cathode flow field 13 is connected to the oxidant outlet 12; the cathode flow field 13 comprises a first transition portion 131, a parallel flow field portion 132, A second transition portion 133 and a serpentine flow field portion 134; the first transition portion 131 is connected to the oxidant inlet 11, and the serpentine flow field portion 134 is connected to the oxidant outlet 12; the parallel flow field portion 132 includes a plurality of parallel distributed straight grooves, the starting end of each straight groove is connected to the first transition portion 131, and the end of each straight groove is connected to the second transition portion 133; the serpentine flow field portion 134 includes a plurality of serpentine grooves, the starting end of each serpentine groove is connected to the second transition portion 133, and the end of each serpentine groove is connected to the oxidant outlet 12.

[0030] Specifically, Figure 1The middle arrow indicates the direction of the oxidant flow in the cathode flow field 13. When the proton exchange membrane fuel cell is working, less water is generated and accumulated in the area near the oxidant inlet 11, and the drainage requirement here is relatively low. The structure of setting the parallel flow field part 132 will not affect the drainage effect and will also help reduce the resistance drop and reduce the performance requirements of the oxidant supply equipment. In the part near the oxidant outlet 12, more water is generated and accumulated, and the drainage requirement here is relatively high. The structure of setting the serpentine flow field part 134 will help increase the cathode surface linear velocity, thereby increasing the resistance drop and drainage driving force, and improving the drainage effect. Therefore, this embodiment can improve the drainage effect of the cathode flow field 13 without increasing the pressure of the cathode oxidant supply equipment, and ensure that the oxidant fully reacts, thereby improving the electrochemical reaction performance of the cathode.

[0031] Also, please continue to read Figure 1 The first transition portion 131 and the second transition portion 133 respectively connect the two ends of each linear groove, so that each linear groove is connected to each other, and each linear groove is connected to the oxidant inlet 11 and the serpentine flow field portion 134, ensuring the transition between the oxidant inlet 11 and the parallel flow field portion 132, and between the parallel flow field portion 132 and the serpentine flow field portion 134, so that the oxidant can smoothly transition between different flow field structures and flow evenly, so that the oxidant can fully react.

[0032] Among them, Figure 1 As shown, the first transition section 131 and the second transition section 133 are both arranged horizontally, and the first transition section 131 and the second transition section 133 are both perpendicular to each linear groove in the parallel flow field; the oxidant inlet 11 is connected to the right end of the first transition section 131, and the starting end of the serpentine flow field section 134 is connected to the left end of the second transition section 133. The two horizontally arranged transition sections ensure that the linear grooves between them are of equal length, thereby making the pressure of the fluid in the linear grooves equal. The oxidant inlet 11 is connected to the right end of the first transition section 131, and the starting end of the serpentine flow field section 134 is connected to the left end of the second transition section 133. The purpose of such arrangement is to make the oxidant flowing through the linear grooves in each parallel flow field from the inlet to the starting end of the serpentine flow field section 134 equal, thereby ensuring that the pressure in each linear groove is equal.

[0033] It should be noted that the shapes of the first transition portion 131 and the second transition portion 133 are not limited to Figure 1 The middle straight line type, such as a triangle or an irregular shape, and the first transition portion 131 and the second transition portion 133 are not limited to being perpendicular to each linear groove, for example, they can have a certain inclination angle with the linear groove, all of which can achieve the purpose of the present invention and are within the protection scope of the present invention.

[0034] In addition, the end of each serpentine groove is located on the left side of the cathode plate body 10, and the structures of each serpentine groove are the same, thereby ensuring that the pressure of the fluid in each serpentine groove is equal.

[0035] In this embodiment, if Figure 1 As shown, the number of the serpentine grooves is two, wherein the serpentine groove has 8 winding portions, i.e., the serpentine groove changes direction 8 times, and the width of the serpentine flow field portion 134 in the vertical direction is equivalent to that of the parallel flow field portion 132. This method is more suitable for batteries that require higher drainage effects and greater power output.

[0036] As a preferred embodiment of the present invention, Figure 1 As shown, in this embodiment, the cathode flow field 13 further includes an inlet slot 135, and the oxidant inlet 11 is connected to the first transition portion 131 through the inlet slot 135. This arrangement can make the pressure value between each inlet slot 135 and each serpentine groove linearly related. If the inlet slot 135 and the serpentine groove have the same flow area, their pressure and flow rate are respectively equal, so that the pressure of the oxidant inlet 11 and the oxidant outlet 12 can be the same, the equipment runs stably, the battery reaction is uniform, and the life is increased.

[0037] As a preferred embodiment of the present invention, Figure 1 As shown, in this embodiment, a plurality of flow guide pillars 136 are respectively provided in the first transition portion 131 and the second transition portion 133, and the flow guide pillars 136 are prismatic or cylindrical. One function of the flow guide pillars 136 is to divert the fluid in the transition portion, and the oxidant enters the next area more evenly after being dispersed by the flow guide pillars 136 in the transition portion; another function of the flow guide pillars 136 is to support the cathode plate 1, bridge the cathode plate 1 with other components, and ensure the transition between the oxidant inlet 11 and the parallel flow field portion 132, and between the parallel flow field portion 132 and the multi-channel serpentine flow field portion 134.

[0038] Embodiment 2

[0039] like Figure 2 As shown, this embodiment provides another cathode plate 1 of a proton exchange membrane fuel cell, which differs from the first embodiment only in that the serpentine groove in this embodiment has four winding parts, that is, the serpentine groove changes direction four times. Compared with the first embodiment, the total flow field area of ​​the cathode plate 1 of this embodiment remains unchanged, and the drainage effect and resistance drop of the cathode flow field 13 are regulated by increasing the parallel flow field area and reducing the serpentine flow field area.

[0040] It should be noted that the cathode plate 1 of this embodiment is more suitable for fuel cells that require relatively low power and drainage rate, wherein the guide pillar 136 may be prismatic or cylindrical.

[0041] Embodiment 3

[0042] like Figure 3 As shown, this embodiment provides another cathode plate 1 of a proton exchange membrane fuel cell, which differs from the first embodiment only in that the number of the serpentine grooves is 3, the serpentine grooves have 4 winding parts, and the number of the inlet grooves 135 is also 3.

[0043] It should be noted that the cathode plate 1 structure of this embodiment further increases the flow area of ​​the serpentine flow field, which is suitable for higher power fuel cells and has a faster drainage rate. The flow guide pillar 136 can still be prismatic or cylindrical.

[0044] Embodiment 4

[0045] This embodiment provides a bipolar plate for a proton exchange membrane fuel cell as the second aspect of the present invention, which includes an anode plate and a cathode plate 1 as described in any of the above embodiments.

[0046] Embodiment 5

[0047] This embodiment provides a proton exchange membrane fuel cell as the third aspect of the present invention, which includes the bipolar plate as described in the fourth embodiment above.

[0048] In summary, the cathode plate 1, bipolar plate and fuel cell of a proton exchange membrane fuel cell provided by the embodiment of the present invention, according to the characteristics of the cathode when the proton exchange membrane fuel cell is working, less water is generated and accumulated in the area near the oxidant inlet 11, and the drainage requirement here is relatively low. The structure of setting the parallel flow field part 132 will not affect the drainage effect and will also help reduce the resistance drop and reduce the performance requirements of the oxidant supply equipment; in the part near the oxidant outlet 12, more water is generated and accumulated, and the drainage requirement here is relatively high. The structure of setting the serpentine flow field part 134 will help increase the cathode surface linear velocity, thereby increasing the resistance drop and drainage driving force, and improving the drainage effect. Therefore, the present invention can improve the drainage effect of the cathode flow field 13 without increasing the pressure of the cathode oxidant supply equipment, and ensure that the oxidant fully reacts, thereby improving the electrochemical reaction performance of the cathode.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A cathode plate of a proton exchange membrane fuel cell, characterized in that: It comprises a cathode plate body, one end of which is provided with an oxidant inlet, and the other end of which is provided with an oxidant outlet; a cathode flow field formed by grooves is provided on one side surface of the cathode plate body, the starting end of the cathode flow field is connected to the oxidant inlet, and the end of the cathode flow field is connected to the oxidant outlet; The cathode flow field comprises a first transition portion, a parallel flow field portion, a second transition portion and a serpentine flow field portion connected in sequence; the first transition portion is connected to the oxidant inlet, and the serpentine flow field portion is connected to the oxidant outlet; The parallel flow field portion includes a plurality of parallel distributed linear grooves, the starting end of each linear groove is connected to the first transition portion, and the end of each linear groove is connected to the second transition portion; The serpentine flow field portion includes a plurality of serpentine grooves, the starting end of each of the serpentine grooves is connected to the second transition portion, and the end of each of the serpentine grooves is connected to the oxidant outlet; The number of the serpentine grooves is at least 2; Each of the serpentine grooves has at least two winding portions.

2. The cathode plate according to claim 1, characterized in that: The first transition section is located at the beginning of the parallel flow field section, and the second transition section is located at the end of the parallel flow field section; the oxidant inlet is connected to the right end of the first transition section, and the beginning of the serpentine flow field section is connected to the left end of the second transition section.

3. The cathode plate according to claim 2, characterized in that: The end of each of the serpentine grooves is located on the left side of the cathode plate body, and the structures of each of the serpentine grooves are the same.

4. The cathode plate according to any one of claims 1 to 3, characterized in that: The cathode flow field further includes an inlet slot, and the oxidant inlet is connected to the first transition portion through the inlet slot.

5. The cathode plate according to any one of claims 1 to 3, characterized in that: A plurality of flow guiding pillars are respectively arranged in the first transition portion and the second transition portion, and the flow guiding pillars are prismatic or cylindrical.

6. A bipolar plate for a proton exchange membrane fuel cell, characterized in that: It comprises an anode plate and a cathode plate as claimed in any one of claims 1 to 5.

7. A proton exchange membrane fuel cell, characterized in that: Comprising the bipolar plate as claimed in claim 6.

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