Fuel cell

Abstract

The utility model relates to the field of new energy, in particular to a fuel cell, which comprises a bipolar plate, a membrane electrode and an electric conductor. The bipolar plate includes a cathode plate and an anode plate forming opposite side surfaces thereof. A plurality of flow channels recessed in the surface of the bipolar plate are formed in the surface of the cathode plate, and the adjacent flow channels are separated by spacing parts. The membrane electrode is arranged between the two bipolar plates, and the two side surfaces are respectively adjacent to the cathode plate and the anode plate of the two bipolar plates. The membrane electrode and the spacing part are separated from each other to form a diffusion space. And the electric conductor is accommodated in the diffusion space and is used for electrically connecting the membrane electrode with the negative plate. The diffusion space is formed by the spacing part of the cathode plate and the membrane electrode, so that oxygen can be diffused in the diffusion space conveniently, and sufficient reaction is facilitated. The membrane electrode is electrically connected with the cathode plate through the electric conductor arranged in the diffusion space, so that poor contact caused by the diffusion space is prevented, and the performance of the electric pile is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to new energy field especially relates to a fuel cell. BACKGROUND

[0002] The hydrogen fuel cell is a kind of power generation device that converts the chemical energy of hydrogen and oxygen into electric energy, under the action of catalyst, hydrogen and oxygen supplied to anode and cathode respectively are chemically reacted by electrolyte to generate water, and release electrons in this process, thereby generating electric current.The battery has the characteristics of no pollution, high efficiency, no noise, etc., and its energy conversion efficiency can reach more than 50%, and only water and heat are generated, without pollutant emission.Currently, hydrogen fuel cell has been widely used in automobile energy, aerospace energy and other fields, how to improve the performance of hydrogen fuel cell stack becomes the research hotspot in new energy field.

[0003] Currently, in order to improve the performance of hydrogen fuel cell stack, the material of membrane electrode is usually optimized.However, the exploration of new material is time-consuming and laborious, which is difficult to realize in a short time.Therefore, on the basis of using existing membrane electrode material, improving the energy conversion efficiency of the battery is an important way to improve the performance of hydrogen fuel cell stack. SUMMARY

[0004] The utility model discloses a kind of fuel cells with higher stack performance by structure.

[0005] To achieve the above purpose, the utility model provides the following technical scheme:

[0006] A kind of fuel cell, characterized in that, comprising:

[0007] Bipolar plate, including forming the two side surfaces of the bipolar plate opposite cathode plate and anode plate, the cathode plate surface forms multiple flow channels recessed in the bipolar plate surface, adjacent the flow channel is separated by spacing portion;

[0008] Membrane electrode, between two the bipolar plate, the diffusion space is formed with spacing portion by the membrane electrode and the spacing portion, electric conductor is provided in the diffusion space, and the electric conductor is used to make the membrane electrode and the cathode plate electrically connected.

[0009] Optionally, the electric conductor is configured as a mesh flat plate structure, and the electric conductor is in contact with the spacing portion of the bipolar plate and the membrane electrode at the same time.

[0010] Optionally, the porosity of the electric conductor is any value in 40%~70%.

[0011] Optionally, the bipolar plate comprises a structure region and a function region, the flow channel and the spacing part are formed in the function region, the function region is sleeved in the middle part of the structure region and is recessed in the structure region, and the electric conductor is embedded in the bipolar plate, is flush with the structure region of the bipolar plate and is attached to the function region of the bipolar plate.

[0012] Optionally, the cathode plate is configured in a wave shape and is connected to the surface of the anode plate, the bipolar plate further comprises a frame-shaped support plate connected to the surface of the cathode plate away from the anode plate to form the structure region of the bipolar plate, and the edges of the support plate, the cathode plate and the anode plate are flush to make the flow channel and the diffusion space communicate with the outside of the bipolar plate.

[0013] Optionally, a plurality of membrane through holes are formed on the membrane electrode, each of the membrane through holes is connected to a fuel gas channel penetrating through the bipolar plate, the fuel gas channel is used to connect the membrane through hole and the side of the anode plate away from the cathode plate, and the electric conductor is provided with a positioning port matched with the fuel gas channel, the positioning port is sleeved outside the fuel gas channel and is used for positioning the electric conductor.

[0014] Optionally, the fuel gas channel comprises a communication port formed in the anode plate, a sealing port formed in the cathode plate and a sealing member configured in an annular shape, the positioning port and the sealing port are matched with the outer circle of the sealing member and are sealingly sleeved outside the sealing member, and the membrane through hole and the communication port are matched with the inner circle of the sealing member and the sealing member is sealingly abutted between the anode plate and the membrane electrode.

[0015] Optionally, the surface of the electric conductor is connected to the spacing part of the bipolar plate.

[0016] Optionally, the electric conductor is made of the same material as the bipolar plate.

[0017] Optionally, the fuel cell comprises a plurality of the membrane electrode.

[0018] The fuel cell has the advantages that the spacing part of the cathode plate and the membrane electrode form a diffusion space, oxygen is diffused in the diffusion space, sufficient oxygen is provided on the cathode side of the membrane electrode, and the reaction is fully carried out.

[0019] Further, the electric conductor is configured as a mesh flat structure, so that the electric conductor sufficiently supports the membrane electrode. At this time, the membrane electrode is no longer in contact with the uneven interval portion, but is in contact with the electric conductor. Mechanical structural changes such as creeping, stretching, cracking, pinhole and the like of the flexible membrane electrode due to extrusion are inhibited, and further, problems such as hydrogen permeation due to local thinning of the membrane, increase in current density, decrease in open circuit voltage, decrease in short circuit resistance, acceleration of mechanical degradation of the proton exchange membrane and the like are inhibited, thereby improving the mechanical stability of the stack. When the cathode gas flows through the electric conductor, the mesh structure of the electric conductor helps to delay the loss of the cathode gas, thereby improving the degree of participation of the cathode gas in the reaction, helping to improve the fullness and utilization of the cathode gas on the surface of the membrane electrode, and promoting the full reaction. In addition, the mesh flat structure of the electric conductor is in full contact with the membrane electrode and the bipolar plate, which helps to fully conduct electricity and improve the performance of the stack.

[0020] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application, and to implement the content of the specification, the following will describe the preferred embodiments of the present application in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a structural schematic diagram of a fuel cell according to an embodiment of the present application;

[0022] Figure 2 FIG. 2 is a partial cross-sectional schematic diagram of a set of bipolar plates, electric conductors and membrane electrodes according to the embodiment of the present application.

[0023] Legend: 1-bipolar plate, 11-cathode plate, 111-flow channel, 112-interval portion, 113-sealing port, 12-anode plate, 121-communication port, 13-supporting plate, 14-enclosing strip, 2-membrane electrode, 21-membrane through hole, 3-electric conductor, 31-positioning port, 4-gas passage, 41-sealing member. DETAILED DESCRIPTION

[0024] The technical scheme of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0025] In the description of the utility model, it needs to explain, the term "center", "upper", "lower", "left", "right", "vertical", "horizontal", "internal", "external" and so on indicate the orientation or position relation based on the orientation or position relation shown in the drawing, only for the convenience of describing the utility model and simplifying the description, and not indicate or imply that the device or element must have a particular orientation, construct and operate in a particular orientation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the utility model, it needs to explain, the term "center", "upper", "lower", "left", "right", "vertical", "horizontal", "internal", "external" and so on indicate the orientation or position relation based on the orientation or position relation shown in the drawing, only for the convenience of describing the utility model and simplifying the description, and not indicate or imply that the device or element must have a particular orientation, construct and operate in a particular orientation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as there is no conflict.

[0028] Please refer to Figure 1 And Figure 2 The utility model discloses a kind of fuel cells, including bipolar plate 1, membrane electrode 2 and electric conductor 3.Bipolar plate 1 includes cathode plate 11 and anode plate 12 forming its opposite two side surfaces.Cathode plate 11 surface forms multiple flow channels 111 recessed in the surface of bipolar plate 1, and adjacent flow channels 111 are separated by spacing part 112.Membrane electrode 2 is arranged between two bipolar plates 1, and two sides are adjacent cathode plate 11 and anode plate 12 of two bipolar plates 1 respectively.Membrane electrode 2 and spacing part 112 form diffusion space with each other.Electric conductor 3 is contained in diffusion space, for making membrane electrode 2 and cathode plate 11 electrically connected.

[0029] By making spacing part 112 of cathode plate 11 and membrane electrode 2 form diffusion space, oxygen is facilitated to diffuse in diffusion space, to provide sufficient oxygen on the cathode side of membrane electrode 2, help reaction to carry out fully.By electrically connecting membrane electrode 2 and cathode plate 11 by electric conductor 3 arranged in diffusion space, prevent poor contact caused by diffusion space, make internal resistance of battery keep at a low level, to help improve the performance of electric pile.

[0030] In some embodiments, electric conductor 3 is configured as a net-like flat plate structure, and electric conductor 3 is in contact with spacing part 112 of bipolar plate 1 and membrane electrode 2 simultaneously.

[0031] The membrane electrode 2 is no longer in contact with the uneven spacing portion 112, but is fully supported in contact with the electric conductor 3. The mechanical structure changes such as creep, stretching, cracking, pinholes, etc. of the flexible membrane electrode 2 due to extrusion are inhibited, and further, problems such as hydrogen permeation caused by local thinning of the membrane, increase in current density, decrease in open circuit voltage, decrease in short-circuit resistance, acceleration of mechanical degradation of the proton exchange membrane, etc. are inhibited, thereby improving the mechanical stability of the stack. In addition, the contact between the net-shaped flat plate structure electric conductor 3 and the membrane electrode 2 and the bipolar plate 1 is sufficient, which helps to fully conduct electricity and improve the performance of the stack.

[0032] In some embodiments, the porosity of the electric conductor 3 is any value in the range of 40% to 70%, for example, any value in the range of 40%, 45%, 50%, 55%, 60%, 65%, and 70%. Too large porosity will result in too small contact area, making the electric conductor 3 insufficient in conductivity and support ability, and too small porosity will result in difficulty in fully diffusing the cathode gas.

[0033] In some embodiments, the bipolar plate 1 includes a structure zone and a functional zone, the flow channel 111 and the spacing portion 112 are formed in the functional zone, the functional zone is sleeved in the middle of the structure zone and is recessed in the structure zone, and the electric conductor 3 is embedded in the bipolar plate 1 and is flush with the structure zone of the bipolar plate 1 and is attached to the functional zone of the bipolar plate 1. The electric conductor 3 is embedded in the bipolar plate 1, which helps to improve the space utilization and facilitates the positioning and limiting of the electric conductor 3, and helps to improve the assembly speed of the fuel cell.

[0034] In some embodiments, the cathode plate 11 is configured in a wave shape and is connected to the surface of the anode plate 12, and the bipolar plate 1 further includes a frame-shaped support plate 13 connected to the surface of the cathode plate 11 away from the anode plate 12, forming the structure zone of the bipolar plate 1, and the edges of the support plate 13, the cathode plate 11, and the anode plate 12 are flush, so that the flow channel 111 and the diffusion space are in communication with the outside of the bipolar plate 1, facilitating the diffusion of the cathode gas from the openings at both ends of the flow channel 111 to the surface of the membrane electrode 2.

[0035] In some embodiments, a plurality of membrane through holes 21 are formed on the membrane electrode 2, each membrane through hole 21 is connected to a fuel gas passage penetrating through the bipolar plate 1, and the fuel gas passage is used to connect the membrane through hole 21 and the side of the anode plate 12 away from the cathode plate 11. The electric conductor 3 is provided with a positioning opening 31 matched with the fuel gas passage, the positioning opening 31 is sleeved outside the fuel gas passage and is used for positioning the electric conductor 3. The positioning opening 31 is used to accurately position the electric conductor 3, facilitating the installation of the electric conductor 3.

[0036] In some embodiments, the fuel gas passage comprises the communication port 121 formed in the anode plate 12, the sealing port 113 formed in the cathode plate 11, and the sealing member 41 configured in a ring shape. The positioning port 31 and the sealing port 113 are fitted to the outer circle of the sealing member 41, and the sealing sleeve is arranged outside the sealing member 41. The membrane through hole 21 and the communication port 121 are fitted to the inner circle of the sealing member 41, and the sealing member 41 is sealed against the anode plate 12 and the membrane electrode 2. This helps to form a fuel gas passage with high sealing degree and reduces the difficulty of installation.

[0037] In some embodiments, the surface of the electric conductor 3 is connected to the spacing portion 112 of the bipolar plate 1. This prevents the displacement of the electric conductor 3 from causing the deformation of the membrane electrode 2, and helps to reduce the installation steps and the difficulty of positioning and limiting.

[0038] In some embodiments, the electric conductor 3 is made of the same material as the bipolar plate 1. This helps to tightly connect the electric conductor 3 and the bipolar plate 1, and reduces the resistance.

[0039] In some embodiments, the fuel cell comprises a plurality of membrane electrodes 2, thereby forming a fuel cell with high total stack performance.

[0040] For details, please refer to the following embodiments.

[0041] Embodiment One:

[0042] Please refer to Figure 1 and Figure 2 , the fuel cell shown in a preferred embodiment of the present application comprises a plurality of membrane electrodes 2, bipolar plates 1 and electric conductors 3 which are sequentially stacked and connected to each other. The bipolar plate 1 comprises a cathode plate 11 and an anode plate 12 which are stacked and connected to each other. The two side surfaces of each membrane electrode 2 are adjacent to the cathode plate 11 and the anode plate 12 of the two bipolar plates 1, respectively. Each electric conductor 3 is arranged between the membrane electrode 2 and the cathode plate 11 of the bipolar plate 1.

[0043] The membrane electrode 2 is configured in a rectangular planar shape, and two identical circular membrane through holes 21 are arranged at the diagonal positions. The material and structure of the membrane electrode 2 are prior art, and the scheme in the present embodiment is applicable to membrane electrodes 2 with different materials and structures, so it is not described here.

[0044] The bipolar plate 1 comprises a cathode plate 11, an anode plate 12 and a support plate 13. The anode plate 12 is a rectangular titanium plate which is shaped to fit the membrane electrode 2. The cathode plate 11 is configured as a bent titanium plate, and two sides of the cathode plate 11 are formed with two groups of rectangular grooves which have the same depth and opposite opening directions. One side of the cathode plate 11 is fixedly connected to the surface of the anode plate 12, and the edge shape of the cathode plate 11 is fitted to the anode plate 12, so that the side of the cathode plate 11 away from the anode plate 12 is formed with a plurality of flow channels 111 which are parallel to each other, and a plurality of spacing portions 112 which separate adjacent two flow channels 111. Both ends and the opening of each flow channel 111 are in communication with the external environment of the bipolar plate 1, so as to facilitate the diffusion of cathode gas, i.e. oxygen or air, to the surface of the membrane electrode 2 close to the cathode plate 11, and to facilitate the full reaction. The height of each spacing portion 112 is equal and flush with each other. The support plate 13 is configured as a rectangular frame structure which is fitted to the anode plate 12, and is connected to the side of the cathode plate 11 away from the anode plate 12, so as to strengthen the structure. The rectangular sheet space surrounded by the support plate 13 is a diffusion space which separates the cathode plate 11 from the membrane electrode 2. In other embodiments, the bipolar plate 1 can be made of conductive material, and can be coated with a coating layer on the surface.

[0045] The bipolar plate 1 further comprises a surrounding strip 14. The long strip-shaped surrounding strip 14 is connected to the side of the anode plate 12 away from the cathode plate 11, and is arranged along the edge of the anode plate 12 to form a ring shape with the first end connected to the second end. The side of the surrounding strip 14 away from the anode plate 12 is connected to the membrane electrode 2, so that a closed fuel gas space is formed among the surrounding strip 14, the anode plate 12 and the membrane electrode 2. The bipolar plate 1 is formed with two gas channels 4 which have the same structure and correspond to the positions of the two membrane through holes 21. The gas channel 4 comprises a sealing member 41, and further comprises a communication opening 121 which penetrates the anode plate 12 and a sealing opening 113 which penetrates the cathode plate 11. The sealing member 41 is configured as a circular ring-shaped cylinder. The sealing opening 113 is fitted to the outer circle of the sealing member 41, and is arranged outside the sealing member 41, so as to prevent the gas in the flow channel 111, the diffusion space and between the anode plate 12 and the cathode plate 11 from entering the inside of the sealing member 41. The membrane through hole 21 and the communication opening 121 are fitted to the inner circle of the sealing member 41, and the sealing member 41 is sealed against the anode plate 12 and the membrane electrode 2, so that each fuel gas space is in communication through the two gas channels 4, and the anode gas, i.e. hydrogen, is facilitated to fill the surface of the membrane electrode 2 close to the anode plate 12 through one gas channel 4, and the excess hydrogen is facilitated to be discharged through the other gas channel 4.

[0046] The net plate-shaped electric conductor 3 is filled in the diffusion space and is in structural cooperation with the diffusion space. One side surface of the electric conductor 3 is in close contact with the spacing portion 112 of the cathode plate 11, and the other side surface is flush with the surface of the support plate 13 away from the cathode plate 11. The electric conductor 3 helps the full diffusion of the cathode gas, and when the cathode gas flows through the electric conductor, the grid structure of the electric conductor helps to slow down the loss of the cathode gas, improves the degree of participation of the cathode gas in the reaction, helps to improve the fullness and utilization rate of the cathode gas on the surface of the membrane electrode, and promotes the full reaction. The electric conductor 3 also helps to support the flexible membrane electrode 2, protects the structure of the membrane electrode 2, prevents performance degradation caused by deformation of the membrane electrode 2, and makes full use of the performance of the membrane electrode 2. In the embodiment, the electric conductor 3 is a titanium net plate, and the porosity is 63%. In other embodiments, the electric conductor 3 can be made of conductive material, and a coating layer can be coated on the surface. The positioning hole formed on the electric conductor 3 cooperates with the outer circle of the sealing element 41, which facilitates the positioning and limiting of the electric conductor 3 relative to the membrane electrode 2 and the bipolar plate 1, helps to reduce the assembly difficulty, and prevents displacement of the electric conductor 3.

[0047] The beneficial effects of the present application are that the electric conductor 3 supports the membrane electrode 2, suppresses the performance degradation caused by deformation of the membrane electrode 2, and provides a larger cathode gas diffusion space through the support of the electric conductor 3, which promotes the full reaction and improves the performance of the fuel cell stack.

[0048] Embodiment two:

[0049] The difference between the present embodiment and embodiment one is that the present embodiment does not provide the support plate 13, and the electric conductor 3 is welded to the cathode plate 11 and is flush with the edge of the cathode plate 11.

[0050] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0051] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A fuel cell, characterized by comprising: The application relates to a bipolar plate (1) and a membrane electrode (2) for a fuel cell. The bipolar plate (1) comprises a cathode plate (11) and an anode plate (12) forming opposite sides of the bipolar plate (1), and the cathode plate (11) has a plurality of flow channels (111) formed on the surface of the bipolar plate (1) and recessed into the surface of the bipolar plate (1), and the flow channels (111) are separated by spacing portions (112). The membrane electrode (2) is arranged between the two bipolar plates (1), and the spacing portions (112) are separated from the membrane electrode (2) to form diffusion spaces, and an electric conductor (3) is arranged in the diffusion spaces and used to electrically connect the membrane electrode (2) and the cathode plate (11).

2. The fuel cell of claim 1, wherein The electric conductor (3) is in the form of a net-shaped flat plate, and the electric conductor (3) simultaneously abuts against the spacing portions (112) of the bipolar plate (1) and the membrane electrode (2).

3. The fuel cell of claim 2, wherein The porosity of the electric conductor (3) is any value within the range of 40% to 70%.

4. The fuel cell of claim 2, wherein The bipolar plate (1) comprises a structure area and a functional area, the flow channels (111) and the spacing portions (112) are formed in the functional area, the functional area is arranged in the middle of the structure area and recessed into the structure area, and the electric conductor (3) is embedded in the bipolar plate (1) and flush with the structure area of the bipolar plate (1) and adheres to the functional area of the bipolar plate (1).

5. The fuel cell of claim 4, wherein The cathode plate (11) is in the form of a wave and connected to the surface of the anode plate (12), and the bipolar plate (1) further comprises a frame-shaped support plate (13) connected to the surface of the cathode plate (11) away from the anode plate (12) to form the structure area of the bipolar plate (1), and the edges of the support plate (13), the cathode plate (11) and the anode plate (12) are flush, so that the flow channels (111) and the diffusion spaces are communicated with the outside of the bipolar plate (1).

6. The fuel cell of claim 2, wherein A plurality of membrane through holes (21) are formed in the membrane electrode (2), each of the membrane through holes (21) is connected with a gas passage (G) penetrating through the bipolar plate (1), the gas passage (G) is used to communicate the membrane through hole (21) with the side of the anode plate (12) away from the cathode plate (11), and the electric conductor (3) is provided with a positioning opening (31) matched with the gas passage (G), the positioning opening (31) is arranged outside the gas passage (G) and used for positioning the electric conductor (3).

7. The fuel cell of claim 6, wherein The gas passage (G) comprises a communication opening (121) formed in the anode plate (12), a sealing opening (113) formed in the cathode plate (11) and a sealing member (41) in the form of a ring, the positioning opening (31) and the sealing opening (113) are matched with the outer circle of the sealing member (41) and are sealingly arranged outside the sealing member (41), and the membrane through hole (21) and the communication opening (121) are matched with the inner circle of the sealing member (41) and the sealing member (41) is sealingly abutted between the anode plate (12) and the membrane electrode (2).

8. The fuel cell of claim 2, wherein The electric conductor (3) is made of the same material as the bipolar plate (1).

9. The fuel cell of claim 2, wherein The surface of the electrical conductor (3) is connected to the spacer (112) of the bipolar plate (1).

10. The fuel cell of any one of claims 1 to 9, wherein The membrane electrode (2) includes a plurality of the membrane electrode (2). The membrane electrode (2) includes a plurality of the membrane electrode (2).

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