Fuel cell with adjustable flow field depth and flow field depth adjusting method

Abstract

The invention discloses a fuel cell with adjustable flow field depth and a flow field depth adjusting method, the fuel cell with adjustable flow field depth comprises a bipolar plate, an elastic element and a membrane electrode, flow field areas are formed on the two side surfaces of the bipolar plate, a plurality of flow channels arranged side by side are formed in the flow field areas, and a ridge structure is formed between every two adjacent flow channels; the elastic element is fixedly arranged on the surface of the ridge structure; and the membrane electrode is fixedly connected with one side, far away from the bipolar plate, of the elastic element and covers the flow field area. The adjusting method comprises the following steps that the stress-strain change relation of the elastic element is obtained; manufacturing a fuel cell; and the flow field depth is regulated. Compared with the prior art, the fuel cell has the advantages that the elastic element is arranged on the ridge structure of the existing bipolar plate, and the compression amount of the elastic element is regulated and controlled by changing the assembly force of the fuel cell, so that the flow field depth is regulated; the flow field depth can be quickly and flexibly adjusted, and the money cost and the time cost for testing the flow field depth in the research and development verification stage are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically to a fuel cell with adjustable flow field depth and a method for adjusting flow field depth. Background Technology

[0002] A fuel cell is a device that can directly convert the chemical energy of combustible gases such as hydrogen into electrical energy. As the core component of a fuel cell, the bipolar plate is responsible for functions such as transporting reactant gases and draining water. Parameters such as the depth and width of the bipolar plate flow field directly affect the mass transfer characteristics of the fuel cell stack, thereby affecting the power generation performance of the fuel cell.

[0003] Generally, fuel cell bipolar plates are fabricated through machining, etching, molding, and other methods. If the performance fails to meet expectations after fabrication, the bipolar plate needs to have its flow field parameters readjusted and undergo further processing verification. For the currently immature fuel cell bipolar plate fabrication technology, both replacing / modifying the molding die and preparing new materials for bipolar plate fabrication are costly in terms of both money and time.

[0004] Therefore, designing a fuel cell bipolar plate with adjustable flow field depth is of great significance for fuel cell development and verification or product manufacturing. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a fuel cell with adjustable flow field depth and a method for adjusting flow field depth, thereby solving the technical problem that the monetary and time costs of adjusting flow field depth are very high in the research and development verification stage of the prior art.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fuel cell with adjustable flow field depth, comprising: bipolar plates, an elastic element, and a membrane electrode assembly. A flow field region is formed on both sides of the bipolar plate, and multiple flow channels are formed in the flow field region, with a ridge structure formed between two adjacent flow channels. The elastic element is fixedly disposed on the surface of the ridge structure; The membrane electrode is fixedly connected to the side of the elastic element away from the bipolar plate and covers the flow field region.

[0007] In some embodiments, a plurality of bipolar plates are arranged side by side, and the membrane electrode is arranged between two adjacent bipolar plates, and the bipolar plates and the membrane electrode are connected by the elastic element.

[0008] In some embodiments, the system further includes end plate assemblies, two of which are respectively arranged on the side of the outermost bipolar plate away from the elastic element and are fixedly connected to the corresponding bipolar plate.

[0009] In some embodiments, the bipolar plate includes an anode plate and a cathode plate that are abutted and fixedly connected, wherein the anode plate has a plurality of anode flow channels on the side away from the cathode plate, and the cathode plate has a plurality of cathode flow channels on the side away from the anode plate.

[0010] In some embodiments, an anode gas inlet and an anode gas outlet are formed on the bipolar plate, and both the anode gas inlet and the anode gas outlet are connected to the anode flow channel.

[0011] In some embodiments, a cathode gas inlet and a cathode gas outlet are formed on the bipolar plate, and both the cathode gas inlet and the cathode gas outlet are connected to the cathode flow channel.

[0012] In some embodiments, the bipolar plate is bonded to the elastic element and the elastic element is bonded to the membrane electrode by conductive adhesive.

[0013] In some embodiments, the elastic element is conductive.

[0014] In some embodiments, the shape and size of the elastic element projected onto the ridge structure are the same as those of the ridge structure.

[0015] Secondly, the present invention also provides a method for adjusting the flow field depth of a fuel cell, applicable to fuel cells with adjustable flow field depth, comprising the following steps: Obtain the stress-strain relationship of the elastic element; The elastic element is mounted onto the bipolar plate to create the fuel cell with adjustable flow field depth; Based on the stress-strain relationship of the elastic element, the assembly force of the fuel cell is adjusted to control the compression of the elastic element, thereby obtaining the required flow field depth.

[0016] Compared with the prior art, the fuel cell with adjustable flow field depth provided by the present invention sets an elastic element on the ridge structure of the existing bipolar plate. The flow channel is formed by the elastic element and the ridge structure. By changing the assembly force of the fuel cell, the compression of the elastic element can be controlled, thereby adjusting the flow field depth. It can quickly and flexibly adjust the flow field depth, which greatly reduces the monetary and time costs of testing the flow field depth during the research and development verification stage. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a fuel cell with adjustable flow field depth provided in an embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the structure of the bipolar plate; Figure 3 This is a flowchart of the flow field depth adjustment method for a fuel cell provided in an embodiment of the present invention; Figure 4 This is a stress-strain curve of an elastic element in one embodiment. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] To address the technical problem that adjusting the flow field depth requires modifying or remaking the bipolar plates, which consumes a lot of time and money, this invention provides a fuel cell with adjustable flow field depth, enabling rapid and low-cost adjustment of the flow field depth.

[0020] Please see Figure 1 and Figure 2 , Figure 1 This is a cross-sectional view of a fuel cell with adjustable flow field depth provided in an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of a bipolar plate.

[0021] The fuel cell with adjustable flow field depth includes a bipolar plate 1, an elastic element 2, and a membrane electrode 3.

[0022] A flow field region is formed on both sides of the bipolar plate 1, and multiple flow channels 11 arranged side by side are formed within the flow field region. A ridge structure 12 is formed between two adjacent flow channels. An elastic element 2 is fixedly disposed on the surface of the ridge structure 12. The membrane electrode 3 is fixedly connected to the side of the elastic element 2 away from the bipolar plate 1 and covers the flow field region.

[0023] In this fuel cell structure, the flow channel 11 and the elastic element 2 together form the actual flow channel, where the depth of the flow channel 11 is fixed, while the thickness of the elastic element 2 is variable. The depth of the actual flow channel can be changed simply by altering the assembly force applied to the fuel cell, thereby changing the actual thickness of the elastic element 2. This adjustment method is simple and convenient, and can significantly save on experimental costs and time.

[0024] In some embodiments, a plurality of bipolar plates 1 are arranged side by side, and a membrane electrode 3 is arranged between two adjacent bipolar plates 1. The bipolar plates 1 and the membrane electrode 3 are connected by an elastic element 2.

[0025] In some embodiments, the fuel cell with adjustable flow field depth further includes endplate assemblies 4. Two endplate assemblies 4 are respectively arranged on the side of the outermost bipolar plate 1 away from the elastic element 2 and are fixedly connected to the corresponding bipolar plate 1. The endplate assemblies 4 can be directly connected to the bipolar plate 1 or connected to the bipolar plate 1 through the elastic element 2.

[0026] In some embodiments, the bipolar plate 1 includes an anode plate 13 and a cathode plate 14 that are attached to and fixedly connected. Multiple anode flow channels 11a are formed on the side of the anode plate 13 away from the cathode plate 14, and multiple cathode flow channels 11b are formed on the side of the cathode plate 14 away from the anode plate 13. In other words, one side of the flow channels 11 on both sides of the bipolar plate 1 is an anode flow channel 11a, and the other side is a cathode flow channel 11b.

[0027] The flow channel 11 on the bipolar plate 1 can have various structural forms, such as serpentine flow channel, parallel flow channel, mesh flow channel, interdigitated flow channel, biomimetic flow channel, etc. This application does not limit the specific structure of the flow channel 11, as long as the shape and size of the elastic element 2 are the same as the ridge structure 12 between two adjacent flow channels 11. In other words, the shape and size of the projection of the elastic element 2 onto the ridge structure 12 are the same as the ridge structure 12.

[0028] In some embodiments, an anode gas inlet 15 and an anode gas outlet 16 are formed on the bipolar plate 1, both of which are connected to the anode flow channel 11a. Anode gas, such as hydrogen, flows into the anode plate 13 through the anode gas inlet 15, flows through the anode flow channel 11a, and is discharged through the anode gas outlet 16.

[0029] In some embodiments, a cathode gas inlet 17 and a cathode gas outlet 18 are formed on the bipolar plate 1, both of which are connected to the cathode flow channel 11b. Cathode gas, such as oxygen or air, flows into the cathode plate 14 through the cathode gas inlet 17, flows through the cathode flow channel 11b, and is discharged through the cathode gas outlet 18.

[0030] The elastic element 2 has good elasticity and conductivity, and can be made of metal gel or elastic conductive fiber.

[0031] In this embodiment, all components are bonded together with conductive adhesive, that is, the bipolar plate 1 is bonded to the elastic element 2, the elastic element 2 is bonded to the membrane electrode 3, and the bipolar plate 1 is bonded to the end plate assembly 4 with conductive adhesive.

[0032] Please see Figure 3 , Figure 3 This is a flowchart of a flow field depth adjustment method for a fuel cell provided in an embodiment of the present invention. The present invention also provides a flow field depth adjustment method for a fuel cell, employing the aforementioned flow field depth-adjustable fuel cell, specifically including the following steps: S1. Obtain the stress-strain relationship of elastic element 2.

[0033] S2. Install the elastic element 2 onto the bipolar plate 1 to create the aforementioned fuel cell with adjustable flow field depth.

[0034] S3. Based on the stress-strain relationship of the elastic element 2, adjust the assembly force of the fuel cell to adjust the compression of the elastic element 2, thereby obtaining the required flow field depth.

[0035] In step S1, a universal testing machine can be used to test the results. A universal testing machine is a material testing machine that integrates tensile, bending, compression, shear, and ring stiffness testing functions. It is mainly used for mechanical property testing of metallic and non-metallic materials and is an ideal testing equipment for industrial and mining enterprises, research institutions, universities, engineering quality supervision stations, and other departments. The universal testing machine is also called a universal material testing machine or a tensile testing machine. The double-screw series features an integrated structure for control, measurement, and operation, incorporating advanced modern technology. It has advantages such as high precision, wide speed range, compact structure, convenient operation, and stable performance.

[0036] The stress-strain relationship obtained from experiments varies depending on the material of elastic element 2. This stress-strain relationship can be a functional equation or a fitted curve. See [link / reference] Figure 4 , Figure 4 This is a stress-strain curve diagram of the elastic element 2 in one embodiment.

[0037] In this embodiment, the depth of the flow channel 11 is 0.5 mm, the initial height of the elastic element 2 is 0.3 mm, and the maximum depth of the actual flow channel is 0.8 mm. When the actual flow channel depth to be tested is 0.67 mm, the corresponding height of the elastic element 2 is 0.17 mm. Referring to the image, the corresponding compressive stress is 0.7 MPa. By adjusting the assembly force of the fuel cell accordingly, a fuel cell with an actual flow channel depth of 0.67 mm can be obtained, and subsequent experiments can be completed.

[0038] After the initial test, based on the required actual flow channel depth for the next set of tests (e.g., 0.66 mm), corresponding to a height of 0.16 mm for elastic element 2, the compressive stress is determined from the graph to be 0.76 MPa. The assembly force of the fuel cell is then adjusted to obtain a fuel cell with an actual flow channel depth of 0.66 mm, completing subsequent tests. This process can be repeated to obtain fuel cells with various flow channel depths, thus enabling tests at different flow channel depths.

[0039] Throughout the experiment, there was no need to modify or redo the bipolar plate 1. Only the assembly force needed to be adjusted according to the stress-strain relationship diagram, which greatly reduced the expenditure of experimental expenses and significantly shortened the experimental time.

[0040] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fuel cell with adjustable flow field depth, characterized in that, include: A bipolar plate, wherein flow field regions are formed on both sides of the bipolar plate, and multiple flow channels are formed within the flow field regions, with a ridge structure formed between two adjacent flow channels; An elastic element, which is fixedly disposed on the surface of the ridge structure; A membrane electrode is fixedly connected to the side of the elastic element away from the bipolar plate and covers the flow field region.

2. The fuel cell with adjustable flow field depth according to claim 1, characterized in that, Multiple bipolar plates are arranged side by side, and the membrane electrode is arranged between two adjacent bipolar plates. The bipolar plates and the membrane electrode are connected through the elastic element.

3. The fuel cell with adjustable flow field depth according to claim 2, characterized in that, It also includes end plate assemblies, two of which are respectively arranged on the side of the outermost bipolar plate away from the elastic element and are fixedly connected to the corresponding bipolar plate.

4. The fuel cell with adjustable flow field depth according to claim 1, characterized in that, The bipolar plate includes an anode plate and a cathode plate that are attached to and fixedly connected. The anode plate has multiple anode flow channels on the side away from the cathode plate, and the cathode plate has multiple cathode flow channels on the side away from the anode plate.

5. The fuel cell with adjustable flow field depth according to claim 4, characterized in that, An anode gas inlet and an anode gas outlet are formed on the bipolar plate, and both the anode gas inlet and the anode gas outlet are connected to the anode flow channel.

6. The fuel cell with adjustable flow field depth according to claim 4, characterized in that, The bipolar plate has a cathode gas inlet and a cathode gas outlet, both of which are connected to the cathode flow channel.

7. The fuel cell with adjustable flow field depth according to claim 1, characterized in that, The bipolar plate is bonded to the elastic element, and the elastic element is bonded to the membrane electrode using conductive adhesive.

8. The fuel cell with adjustable flow field depth according to claim 1, characterized in that, The elastic element is conductive.

9. The fuel cell with adjustable flow field depth according to claim 1, characterized in that, The shape and size of the elastic element projected onto the ridge structure are the same as those of the ridge structure.

10. A method for adjusting the flow field depth of a fuel cell, characterized in that, The fuel cell applicable to any one of claims 1-9 includes the following steps: Obtain the stress-strain relationship of the elastic element; The elastic element is mounted onto the bipolar plate to create the fuel cell with adjustable flow field depth; Based on the stress-strain relationship of the elastic element, the assembly force of the fuel cell is adjusted to control the compression of the elastic element, thereby obtaining the required flow field depth.

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