Fuel cell bipolar plate, fuel cell stack and fuel cell stack structure

Abstract

The present application discloses a fuel cell bipolar plate, a fuel cell stack, and a fuel cell stack structure. The fuel cell bipolar plate has a three-dimensional wavy structure. Two opposing wavy side surfaces serve as flow field sides of the fuel cell bipolar plate, wherein the first flow field side is provided with an oxidant flow field, and the second flow field side is provided with a fuel flow field. The oxidant inlet and the oxidant outlet are connected via a flow channel in the oxidant flow field; and the fuel inlet and the fuel outlet are connected via a flow channel in the fuel flow field. The three-dimensional wavy bipolar plate design enhances the flow of cathode and anode media, increases the vector of media impacting the membrane electrode, strengthens mass transfer, and contributes to improved electrical performance. Simultaneously, this design increases the effective area of ​​the membrane electrode per unit volume of the stack, which is beneficial to improving the specific power of the stack.

Description

Technical Field

[0001] The present application relates to a fuel cell bipolar plate, a fuel cell stack and a fuel cell stack structure, belonging to the field of fuel cell technology. Background Art

[0002] A fuel cell is a device that converts the chemical energy stored in compound fuels directly into electrical energy through chemical reactions. As the core component of a fuel cell, the bipolar plate plays many important roles, such as supporting the membrane electrode, separating hydrogen and oxygen, collecting electrons, and conducting heat. Its performance depends largely on the flow field structure.

[0003] With the development of industry, high-power fuel cells are being used more widely and in greater demand. Improving the volume and weight-to-power ratio of fuel cells is an important goal. At the same time, consideration should be given to enhancing the flow of cathode and anode media, strengthening mass transfer, and improving electrical performance.

[0004] During battery operation, a large amount of heat is generated when electrochemical reactions occur. In order to maintain the normal operating temperature of the battery stack, the battery stack needs to be cooled. The traditional battery stack has repeatedly stacked coolant chambers that occupy a large volume and weight in the battery stack. As the power level of the battery stack increases, the proportion becomes more and more obvious. How to effectively maintain the temperature of the battery stack while reducing the volume and weight and increasing the power density of the battery stack is becoming more and more important. Summary of the Invention

[0005] To solve the above problems, the fuel cell bipolar plate and stack proposed in the present application adopt a three-dimensional S-wave structure. Unlike the previous arrangement of flow channels on a flat plate, the main reaction zone of the bipolar plate itself is S-wave shaped, and the cathode and anode medium inlet and outlet parts on both sides are still flat areas. The two bipolar plates are combined with flexible membrane electrodes with the same S-wave shape to form a battery unit, which greatly increases the effective area of ​​the membrane electrode per unit volume of the stack and improves the volume-to-power ratio of the stack. At the same time, the three-dimensional S-wave structure is adopted, and the flow direction changes at the peaks and troughs of the flow channel, so that the fluid has a vector to impact the membrane electrode surface, thereby improving the mass transfer coefficient of the cathode and anode gases, making it easier for them to enter the diffusion layer, thereby improving fuel utilization, which is conducive to increasing current density and reducing the stoichiometric ratio of the reaction medium, and improving the performance of the stack.

[0006] The heat exchange module is independent of the fuel cell stack. Unlike the traditional fuel cell stack with a single cell-cooling channel-single cell repeated stacking arrangement, it is placed on both sides of the fuel cell stack to minimize the width of the bipolar plate. The heat inside the fuel cell stack is extracted by heat conduction, and the heat is taken out by convection heat transfer of the flow medium in the side heat exchange module. The heat is circulated and dissipated, which changes the traditional design of alternating cooling channels and reaction channels. The coolant cavity is eliminated in the stacking direction of the bipolar plates, which is beneficial to reducing the volume and weight of the fuel cell stack, thereby improving the specific power of the fuel cell stack. The combined structure of the fuel cell stack and the heat exchange module makes it easy to integrate multi-module and high-power fuel cells.

[0007] In one aspect of the present application, a fuel cell bipolar plate is provided, wherein the fuel cell bipolar plate comprises a fuel inlet, a fuel outlet, an oxidant inlet, and an oxidant outlet, and the fuel cell bipolar plate has a three-dimensional wavy structure;

[0008] The two opposite wavy side surfaces are flow field sides of the fuel cell bipolar plate, wherein the first flow field side is provided with an oxidant flow field, and the second flow field side is provided with a fuel flow field;

[0009] The oxidant inlet is connected to the oxidant outlet through a flow channel in the oxidant flow field;

[0010] The fuel inlet is communicated with the fuel outlet through a flow channel in the fuel flow field.

[0011] Specifically, an oxidant flow field and a fuel flow field are respectively provided on the two side surfaces of the bipolar plate; the bipolar plate is a three-dimensional S-wave structure, and a fuel inlet, a fuel outlet, an oxidant inlet, and an oxidant outlet are provided on the four edges of the bipolar plate.

[0012] The three-dimensional S-wave structure has a change in flow direction at the crests and troughs of the flow channel, which gives the fluid a vector to impact the membrane electrode surface, improves the mass transfer coefficient of the cathode and anode gases, and makes it easier for them to enter the diffusion layer.

[0013] Optionally, the bipolar plate is provided with a first end face, a main reaction area and a second end face which are smoothly connected in sequence along the long side direction;

[0014] The plate body of the main reaction zone is the three-dimensional wavy structure;

[0015] The first end surface is a planar area;

[0016] The second end surface is a planar area.

[0017] Optionally, the fuel inlet and the oxidant outlet are respectively provided on the first end surface;

[0018] The fuel outlet and the oxidant inlet are respectively arranged on the second end surface.

[0019] As a specific implementation method, the main reaction zone of the bipolar plate is in a three-dimensional S-wave shape, and the cathode and anode medium inlet and outlet parts on both sides are still flat areas.

[0020] Optionally, the corrugation angle of the three-dimensional wavy structure is 100-150°.

[0021] Another aspect of the present application provides a fuel cell stack, the fuel cell stack comprising a fuel cell stack unit and a heat exchange unit;

[0022] The fuel cell stack unit comprises a first end portion, a fuel cell stack main body module, and a second end portion that are fixedly connected in sequence;

[0023] The fuel cell stack main module is formed by alternating N+1 bipolar plate groups and N membrane electrode groups, which include, in sequence, a first bipolar plate group, a first membrane electrode group, a second bipolar plate group, a second membrane electrode group, ... an Nth membrane electrode group, and an N+1th bipolar plate group, wherein N≥3 and N is an integer;

[0024] The bipolar plate assembly is formed by stacking two of the above-mentioned fuel cell bipolar plates;

[0025] Two opposite sides of the membrane electrode are respectively adjacent to the flow field sides of the fuel cell bipolar plate;

[0026] The heat exchange unit includes two heat exchange modules;

[0027] The heat exchange modules are located on both sides of the fuel cell stack main body module.

[0028] In the present application, the membrane electrode and the bipolar plate are alternately stacked one by one.

[0029] In the present application, the main reaction zone of the bipolar plate is a three-dimensional S-wave shape, and the inlet and outlet parts of the cathode and anode media on both sides are still planar areas. The two bipolar plates are combined with the membrane electrode with the same S-wave shape to form an S-shaped battery unit; the two side surfaces of a bipolar plate in the bipolar plate group are respectively provided with an oxidant flow field and a fuel flow field; the flow field modes such as parallel and serpentine are not restricted, and turbulence can also be set; the heat exchange module is independent of the fuel cell stack and placed on both sides of the fuel cell stack. Fins can be set inside to enhance heat transfer. The heat inside the fuel cell stack is first transferred from the middle to the side in the form of heat conduction, and then carried away by convection of the circulating coolant in the side heat exchange module.

[0030] In the present application, a fuel inlet, a fuel outlet, an oxidant inlet, and an oxidant outlet are provided on the short sides of the bipolar plates. The fuel inlet and oxidant outlet are provided on one short side of the bipolar plate, while the fuel outlet and oxidant inlet are provided on the other short side. The bipolar plate, membrane electrode, and bipolar plate are stacked in sequence to form a repeating unit in the stack, i.e., a single cell. In each single cell, the fuel of one bipolar plate enters from the fuel inlet on one short side and is discharged from the fuel outlet on the other short side of the bipolar plate. The oxidant of the other bipolar plate enters from the oxidant inlet on one short side of the bipolar plate and is discharged from the oxidant outlet on the other short side. The macroscopic flow directions of the fuel and oxidant are opposite. The long sides on both sides are in contact with the side heat exchange module through materials such as thermally conductive insulating pads, which guide the reaction heat of the stack from the inside and then transfer it away through convection.

[0031] Optionally, 3≤N≤200.

[0032] Optionally, the membrane electrode has a three-dimensional wavy structure that is compatible with the fuel cell bipolar plate.

[0033] The fuel cell stack proposed in this application adopts a three-dimensional S-wave structure for the bipolar plates, which is combined with a flexible membrane electrode that is also S-wave shaped, thereby increasing the effective area of ​​the membrane electrode per unit volume of the stack and improving the volume-to-power ratio of the stack. At the same time, the three-dimensional S-wave structure is adopted to enhance mass transfer and improve stack performance.

[0034] Optionally, the fuel cell stack main body module includes an opposite side surface I and side surface II, an opposite side surface III and side surface IV, and an opposite first stacking surface and a second stacking surface;

[0035] Wherein, the first side surface is formed by stacking the first end surfaces of the fuel cell bipolar plates;

[0036] The second side surface is formed by stacking the second end surfaces of the fuel cell bipolar plates;

[0037] In the first bipolar plate assembly, the flow field side away from the first membrane electrode is the third side;

[0038] In the N+1 bipolar plate group, the flow field side away from the Nth membrane electrode is the IV side;

[0039] The first stacking surface and the second stacking surface are formed by alternately stacking the bipolar plate group and the membrane electrode, and the first stacking surface is perpendicular to the I side surface and the III side surface respectively.

[0040] Optionally, the heat exchange module is fixed on the plane where the first stacking surface is located and the plane where the second stacking surface is located respectively;

[0041] The heat exchange module includes a heat exchange module cavity plate and a heat exchange module cover plate;

[0042] The heat exchange module cavity plate is provided with a baffle structure or a fin structure to form a coolant flow field;

[0043] The heat exchange module cover plate is fixed to the heat exchange module cavity plate to form a baffle cavity.

[0044] Optionally, a coolant inlet and a coolant outlet are further provided on the cavity plate of the heat exchange module.

[0045] Optionally, a thermally conductive insulating pad is provided between the heat exchange module and the fuel cell stack main module.

[0046] In this application, the heat exchange module is independent of the fuel cell stack and is placed on both sides of the fuel cell stack. It is in contact with the fuel cell stack through a thermally conductive insulating pad. The heat exchange module is sealed by welding, and a variety of fins and deflection structures can be set inside. A coolant inlet and a coolant outlet are set. The coolant enters the cooling channel from the inlet and flows out from the outlet; the width of the bipolar plate is minimized as much as possible, and the heat inside the fuel cell stack is extracted by heat conduction. At the same time, the heat is brought out by convection heat transfer of the flowing medium in the side heat exchange module, and the heat is circulated and dissipated. The design of the alternating arrangement of traditional cooling channels and reaction channels is changed, and the coolant cavity is eliminated in the stacking direction of the bipolar plates, which is beneficial to reducing the volume and weight of the fuel cell stack, thereby improving the power density of the fuel cell stack.

[0047] Optionally, the first end portion includes a stack end plate I, a stack end plate II, an insulating plate I, and a current collecting plate I fixed in sequence;

[0048] Side A of the current collecting plate I is adjacent to the insulating plate I, and side B opposite to side A is adjacent to side III of the fuel cell stack main module, with a sealing gasket provided between side B and side III;

[0049] The second end portion includes a stack end plate III, an insulating plate II, and a current collecting plate II fixed in sequence;

[0050] The side surface C of the current collecting plate II is adjacent to the insulating plate, and the side surface D opposite to the side surface C is adjacent to the side surface E of the fuel cell stack main module;

[0051] In the fuel cell stack main body module, a side surface F opposite to the side surface E is adjacent to the IV side surface of the single cell module.

[0052] Optionally, the sealing gasket has a three-dimensional wavy structure adapted to the fuel cell bipolar plate;

[0053] The current collecting plate I and the current collecting plate II independently meet the following requirements:

[0054] Having two opposite sides, wherein

[0055] The side away from the fuel cell stack main module is a plane.

[0056] The side surface adjacent to the fuel cell stack main body module has a three-dimensional wavy structure adapted to the fuel cell bipolar plate.

[0057] In this application, the combined structure of the fuel cell stack and the heat exchange module can easily realize the integration of multi-module, high-power stacks. Through the fixed connection between the heat exchange module and the stack through the connecting ears, the stack can be combined in series and parallel. The inlet and outlet of all media are on the same side, which is convenient for external pipeline connection.

[0058] In another aspect of the present application, a fuel cell stack structure is provided, which includes at least one fuel cell stack, wherein the fuel cell stack is selected from the above-mentioned fuel cell stacks.

[0059] Optionally, when the fuel cell stack structure includes at least two fuel cell stacks, the fuel cell stacks are connected in series and / or in parallel.

[0060] In another aspect of the present application, a proton exchange membrane fuel cell is provided, comprising the above-mentioned fuel cell bipolar plate and / or the above-mentioned fuel cell stack;

[0061] The fuel in the proton exchange membrane fuel cell is at least one of hydrogen and reformed hydrogen-rich gas.

[0062] The beneficial effects of this application include:

[0063] (1) The fuel cell bipolar plate and stack proposed in this application have a three-dimensional S-wave structure. Unlike the previous arrangement of flow channels on a flat plate, the main reaction area of ​​the bipolar plate itself is in the shape of an S wave, and the cathode and anode medium inlet and outlet parts on both sides are still flat areas. The two bipolar plates are combined with flexible membrane electrodes with the same S-wave shape to form a battery unit, which greatly increases the effective area of ​​the membrane electrode per unit volume of the stack and improves the volume-to-power ratio of the stack. At the same time, the three-dimensional S-wave structure is adopted, and the direction of flow changes at the crests and troughs of the flow channel, so that the fluid has a vector to impact the membrane electrode surface, thereby improving the mass transfer coefficient of the cathode and anode gases and making it easier for them to enter the diffusion layer, thereby improving the fuel utilization rate, which is conducive to increasing the current density and reducing the stoichiometric ratio of the reaction medium, and improving the performance of the stack.

[0064] (2) The fuel cell bipolar plates and stacks proposed in this application are particularly suitable for proton exchange membrane fuel cells that use hydrogen or reformed hydrogen-rich gas as fuel. The three-dimensional wavy bipolar plate design enhances the flow of cathode and anode media, increases the vector of the media impacting the membrane electrode, strengthens mass transfer, and contributes to improved electrical performance. At the same time, this design increases the effective area of ​​the membrane electrode per unit volume of the stack, which is beneficial to the improvement of the stack's specific power.

[0065] (3) The heat exchange module is independent of the fuel cell stack. Unlike the traditional fuel cell stack with a single cell-cooling channel-single cell repeated stacking arrangement, it is placed on both sides of the fuel cell stack to minimize the width of the bipolar plate. The heat inside the fuel cell stack is extracted by heat conduction, and the heat is taken out by convection heat transfer of the flow medium in the side heat exchange module. The heat is circulated and dissipated. The new heat dissipation structure is used to change the design of the alternating arrangement of the traditional cooling flow channel and the reaction flow channel. The coolant cavity is eliminated in the stacking direction of the bipolar plates, which is beneficial to reduce the volume and weight of the fuel cell stack, thereby improving the specific power of the fuel cell stack. The combined structure of the fuel cell stack and the heat exchange module makes it easy to realize the integration of multi-module and high-power fuel cell stacks. The heat exchange module is independent of the fuel cell stack and uses welding to avoid the leakage of the circulating cooling medium. It is also conducive to integration and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a schematic diagram of the decomposition of the main components of the fuel cell stack of this application.

[0067] Figure 2 In the figure, (a) is a schematic diagram of the bipolar plates and the inlets and outlets of the battery stack of the present application, (b) is a schematic diagram of the flow field of the bipolar plates of a common battery stack, and (c) is a schematic diagram of the corrugated details of the bipolar plates of the battery stack of the present application.

[0068] Figure 3 This is a schematic diagram of the bipolar plate sealing gasket of the battery stack of this application.

[0069] Figure 4 This is a schematic diagram of the stack membrane electrode of this application.

[0070] Figure 5 This is a schematic diagram of the current collecting plate of the battery stack of this application.

[0071] Figure 6 This is a schematic diagram of the end plates on both sides of the fuel cell stack of this application.

[0072] Figure 7 This is a schematic diagram of the combination of the fuel cell stack and the heat exchange module of this application.

[0073] Figure 8 This is a schematic diagram of the heat exchange module of the fuel cell stack of this application.

[0074] Figure 9 In the figure, (a) is a schematic diagram of the arrangement of repeating units of a common battery stack, and (b) is a schematic diagram of the arrangement of repeating units of the battery stack of the present application.

[0075] Figure 10 This is a schematic diagram of the integrated fastening structure of the battery stack in this application.

[0076] Figure 11 This is a schematic diagram of the multi-stack integrated combination of this application.

[0077] List of parts and reference numerals:

[0078] 1. Stack end plate I, 2. Stack end plate II, 3. Stack end plate III, 4. Insulation plate, 5. Current collecting plate;

[0079] 6. Fuel and oxidant flow field bipolar plates, 7. Stack membrane electrode (MEA), 8. Stack body, 9. Flow field sealing gasket;

[0080] 10. Heat exchange module cavity plate, 11. Heat exchange module cover plate, 12. Thermal insulation pad;

[0081] 13. Stack fastening bolts, 14. Stack compression spring;

[0082] A, stack anode fuel inlet, B, stack anode fuel outlet, C, stack cathode oxidant inlet, D, stack cathode oxidant outlet;

[0083] E, circulating coolant inlet, F, circulating coolant outlet, G, end plate and external connection fixing hole, H, heat exchange module and external connection fixing hole, I, compression spring positioning groove;

[0084] a. Fuel flow field of the stack anode, b. oxidant flow field of the stack cathode, c. Circulating coolant flow field, θ, corrugation angle. DETAILED DESCRIPTION

[0085] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0086] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0087] Example 1

[0088] The fuel cell stack of the present invention is as follows Figure 1 As shown, it includes a stack end plate I1, a stack end plate II2, a stack end plate III3, an insulating plate 4, a current collecting plate 5, a fuel and oxidant flow field bipolar plate 6, a stack membrane electrode (MEA) 7, a stack body 8, a flow field sealing gasket 9, a stack fastening bolt 13, and a stack compression spring 14. Figure 1 The fuel and oxidant flow field bipolar plates 6 and the stack membrane electrode 7 are alternately stacked in sequence, as shown in FIG. Figure 9 The order shown in Figure (b).

[0089] The bipolar plates in this application are as follows Figure 2 As shown in Figure (a), different from Figure 2 The conventional bipolar plate flow channels shown in Figure (b) are arranged in a wavy shape in the two-dimensional plane direction of the bipolar plate. The main reaction area of ​​the bipolar plate of the stack invented in this application is a three-dimensional S-wave shape. The cathode and anode medium inlet and outlet parts on both sides are flat areas. The two side surfaces are respectively provided with a stack anode fuel flow field a and a stack cathode oxidant flow field b, as shown in FIG. Figure 2 As shown in Figure (c); the flow field modes include parallel, serpentine, corrugated, etc., and turbulence can also be set; Figure 2 As shown in (c), the recommended corrugation angle θ of the wave shape S in the main reaction area of ​​the bipolar plate is 100-150°. In this embodiment, 120° is used. During operation of the stack, internal heat is first conducted from the center to the two sides by the bipolar plates, and then carried away by convection of the circulating fluid in the channels of the external heat exchange module.

[0090] like Figure 2 As shown, the bipolar plate is rectangular as a whole, and a stack anode fuel inlet A, a stack anode fuel outlet B, a stack cathode oxidant inlet C, and a stack cathode oxidant outlet D are provided on the short sides of the bipolar plate.

[0091] The fuel of one bipolar plate in each single cell enters from the anode fuel inlet A of the short side stack on one side and is discharged from the anode fuel outlet B of the short side stack on the other side of the bipolar plate. The oxidant of the other bipolar plate enters from the cathode oxidant inlet C of the short side stack on one side of the bipolar plate and is discharged from the cathode oxidant outlet D of the short side stack on the other side. The macroscopic flow directions of the fuel and the oxidant are opposite.

[0092] like Figure 3 The flow field sealing gasket 9 between the bipolar plate and the membrane electrode is shown. It has the same structure as the bipolar plate and is a three-dimensional S-wave shape in the main reaction area. The inlet and outlet parts of the cathode and anode media on both sides are still flat areas.

[0093] like Figure 4 The stack membrane electrode 7 is shown, which has the same structure as the bipolar plate. It is a three-dimensional S-wave shape in the main reaction area, and the cathode and anode medium inlet and outlet parts on both sides are still flat areas.

[0094] like Figure 5 The figure shows the current collecting plates 5 on both sides of the fuel cell stack. The side facing the inside of the fuel cell stack has the same structure as the bipolar plate. It is S-shaped in the main reaction area. The inlet and outlet parts of the cathode and anode media on both sides are still flat areas. The side facing the outside of the fuel cell stack is flat, which serves as a conversion plate to lay the foundation for the outer insulation and end plates to be converted into flat plates.

[0095] like Figure 6Shown are the stack end plate I1 and the stack end plate II2. Both end plates have circular grooves on one side for positioning the stack compression spring 14. The stack is fastened together with the stack fastening bolts 13 and the stack end plate III3 on ​​the other side of the stack. At the same time, the stack end plates I1 and III3 are both provided with external connection ears with fixing holes G thereon for connection with the external heat exchange module cavity plate 10.

[0096] like Figure 7 As shown, the heat exchange module of the fuel cell stack of the present application is placed on the two long sides of the stack, with a thermal insulation pad 12 in the middle. The heat exchange module is made by welding, as shown in FIG. Figure 8 As shown, the heat exchange module includes a heat exchange module cavity plate 10 and a heat exchange module cover plate 11, with connecting ears H provided around it, which are fixed to the connecting ears of the fuel cell stack end plate through fixing holes. The internal flow field c of the heat exchange module can be provided with multiple deflections or various fin structures to enhance heat transfer. The coolant flowing therein will not enter the fuel cell stack reaction area. The heat of the fuel cell stack is conducted out of the interior by the bipolar plate, and the heat is taken out by the convection heat transfer of the flowing medium in the side heat exchange module, and the heat is circulated externally.

[0097] like Figure 9 As shown, in order to obtain a better temperature uniformity distribution effect, the width of the bipolar plate should be minimized in the fuel cell stack of the present application, which is different from the conventional stack repeating unit such as Figure 9 The arrangement of Oil1-Air-MEA-H2-Oil2-Air-MEA-H2 shown in Figure (a) is repeated, but the heat exchange module 10 is placed on the side of the stack, as shown in the figure. Figure 9 As shown in Figure (b), the stack repeating units are arranged in a repeated and superimposed form of Air-MEA-H2-Air-MEA-H2, which changes the traditional design of alternating cooling channels and reaction channels and eliminates the coolant cavity in the stacking direction, which is beneficial to reducing volume and weight, thereby improving the stack power ratio; the heat exchange module is independent of the stack and uses welding to avoid leakage of the circulating cooling medium, while facilitating integration and maintenance.

[0098] like Figure 10 As shown, the anode fuel inlet and outlet A and B of the fuel stack, the cathode oxidant inlet and outlet C and D of the fuel stack, and the circulating coolant inlet and outlet E and F of the heat exchange module are all located on one side of the fuel stack to facilitate pipeline connection and module integration.

[0099] like Figure 11 As shown, the combined structure of the fuel cell stack and the heat exchange module can easily realize the integration of multiple modules and high-power stacks. The heat exchange module and the stack are fixedly connected through the connecting ears, demonstrating the integration of 15 stack modules. The stack of this application is designed in the membrane electrode main reaction area of ​​300cm 2 、Current density 400mA / cm 2Under the working condition of 0.6V voltage, it integrates 140 membrane electrodes and can output 10kW of power. The battery stack can be combined in series or parallel. Figure 11 The integration of a 150kW power module is demonstrated, with all media inlets and outlets on the same side, facilitating external pipeline connections.

[0100] A fuel cell bipolar plate and stack structure is described above. Those skilled in the art in the art to which the present invention relates should understand that any modifications, scaling of dimensions and structures, equivalent replacements or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0101] The fuel cell bipolar plates and stack proposed in the present invention have a three-dimensional S-wave structure. Unlike conventional arrangements in which flow channels are arranged on a flat plate, the main reaction zone of the bipolar plate itself is S-wave-shaped, while the cathode and anode medium inlet and outlet portions on both sides remain flat areas. The two bipolar plates, in conjunction with the membrane electrode, also have an S-wave shape, form a battery unit, greatly increasing the effective membrane electrode area per unit volume of the stack and improving the stack volume-to-power ratio. Furthermore, the three-dimensional S-wave structure allows for changes in flow direction at the peaks and troughs of the flow channel, providing a vector for the fluid to impact the membrane electrode surface, thereby increasing the mass transfer coefficient of the cathode and anode gases and making it easier for them to enter the diffusion layer, thereby improving fuel utilization, facilitating increased current density and a reduction in the stoichiometric ratio of the reaction medium, and enhancing stack performance.

[0102] The heat exchange module is independent of the fuel cell stack. Unlike the traditional fuel cell stack with a single cell-cooling channel-single cell repeated stacking arrangement, it is placed on both sides of the fuel cell stack to minimize the width of the bipolar plate. The heat inside the fuel cell stack is extracted by heat conduction, and the heat is taken out by convection heat transfer of the flow medium in the side heat exchange module. The heat is circulated and dissipated, which changes the traditional design of alternating cooling channels and reaction channels. The coolant cavity is eliminated in the stacking direction of the bipolar plates, which is beneficial to reducing the volume and weight of the fuel cell stack, thereby improving the specific power of the fuel cell stack. The combined structure of the fuel cell stack and the heat exchange module makes it easy to integrate multi-module and high-power fuel cells.

[0103] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A fuel cell stack, characterized in that: The fuel cell stack includes a fuel cell stack unit and a heat exchange unit; The fuel cell stack unit comprises a first end portion, a fuel cell stack main body module, and a second end portion that are fixedly connected in sequence; The fuel cell stack main module is formed by alternating N+1 bipolar plate groups and N membrane electrode groups, which include, in sequence, a first bipolar plate group, a first membrane electrode group, a second bipolar plate group, a second membrane electrode group, ... an Nth membrane electrode group, and an N+1th bipolar plate group, wherein N≥3 and N is an integer; The bipolar plate assembly is formed by stacking two fuel cell bipolar plates; Two opposite sides of the membrane electrode are respectively adjacent to the flow field sides of the fuel cell bipolar plate; The heat exchange unit includes two heat exchange modules; The fuel cell bipolar plate comprises a fuel inlet, a fuel outlet, an oxidant inlet, and an oxidant outlet, and the fuel cell bipolar plate is a three-dimensional wavy structure; The two opposite wavy side surfaces are flow field sides of the fuel cell bipolar plate, wherein the first flow field side is provided with an oxidant flow field, and the second flow field side is provided with a fuel flow field; The oxidant inlet is connected to the oxidant outlet through a flow channel in the oxidant flow field; The fuel inlet and the fuel outlet are connected through a flow channel in the fuel flow field; There are changes in the direction of flow at the crests and troughs of the flow channel; The membrane electrode has a three-dimensional wavy structure adapted to the fuel cell bipolar plate; The fuel cell stack main body module includes an opposite first side and a second side, an opposite third side and a fourth side, and an opposite first stacking surface and a second stacking surface; The heat exchange modules are respectively fixed on the plane where the first stacking surface is located and the plane where the second stacking surface is located.

2. The fuel cell stack according to claim 1, characterized in that: The bipolar plate is provided with a first end face, a main reaction area and a second end face which are smoothly connected in sequence along the long side direction; The plate body of the main reaction zone is the three-dimensional wavy structure; The first end surface is a planar area; The second end surface is a planar area.

3. The fuel cell stack according to claim 2, characterized in that: The fuel inlet and the oxidant outlet are respectively arranged on the first end surface; The fuel outlet and the oxidant inlet are respectively arranged on the second end surface.

4. The fuel cell stack according to claim 1, wherein: The corrugation angle of the three-dimensional wavy structure is 100-150°.

5. The fuel cell stack according to claim 1, characterized in that: 3≤N≤200。 6. The fuel cell stack according to claim 1, characterized in that: The first side surface is formed by stacking the first end surfaces of the fuel cell bipolar plates; The second side surface is formed by stacking the second end surfaces of the fuel cell bipolar plates; In the first bipolar plate assembly, the flow field side away from the first membrane electrode is the third side; In the N+1 bipolar plate group, the flow field side away from the Nth membrane electrode is the IV side; The first stacking surface and the second stacking surface are formed by alternately stacking the bipolar plate group and the membrane electrode, and the first stacking surface is perpendicular to the I side surface and the III side surface respectively.

7. The fuel cell stack according to claim 1, characterized in that: The heat exchange module includes a heat exchange module cavity plate and a heat exchange module cover plate; The heat exchange module cavity plate is provided with a baffle structure or a fin structure to form a coolant flow field; The heat exchange module cover plate is fixed to the heat exchange module cavity plate to form a baffle cavity.

8. The fuel cell stack according to claim 7, characterized in that: The heat exchange module cavity plate is also provided with a coolant inlet and a coolant outlet.

9. The fuel cell stack according to claim 7, characterized in that: A thermally conductive insulating pad is provided between the heat exchange module and the fuel cell stack main body module.

10. The fuel cell stack according to claim 6, characterized in that: The first end portion includes a stack end plate I, a stack end plate II, an insulating plate I, and a current collecting plate I fixed in sequence; Side A of the current collecting plate I is adjacent to the insulating plate I, and side B opposite to side A is adjacent to side III of the fuel cell stack main module, with a sealing gasket provided between side B and side III; The second end portion includes a stack end plate III, an insulating plate II, and a current collecting plate II fixed in sequence; The side surface C of the current collecting plate II is adjacent to the insulating plate, and the side surface D opposite to the side surface C is adjacent to the side surface E of the fuel cell stack main module; In the fuel cell stack main body module, a side surface F opposite to the side surface E is adjacent to the IV side surface of the fuel cell stack main body module.

11. The fuel cell stack according to claim 10, characterized in that: The sealing gasket has a three-dimensional wavy structure adapted to the fuel cell bipolar plate.

12. The fuel cell stack according to claim 10, characterized in that: The current collecting plate I and the current collecting plate II independently meet the following requirements: Having two opposite sides, wherein The side away from the fuel cell stack main module is a plane. The side surface adjacent to the fuel cell stack main body module has a three-dimensional wavy structure adapted to the fuel cell bipolar plate.

13. A fuel cell stack structure, characterized in that: The fuel cell stack structure comprises at least one fuel cell stack, wherein the fuel cell stack is selected from the fuel cell stack according to any one of claims 1 to 12; When the fuel cell stack structure includes at least two fuel cell stacks, the fuel cell stacks are connected in series and / or in parallel.

14. A proton exchange membrane fuel cell, characterized in that: A fuel cell stack comprising any one of claims 1 to 12; The fuel in the proton exchange membrane fuel cell is at least one of hydrogen and reformed hydrogen-rich gas.

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