An air intake assembly for a fuel cell stack, a fuel cell stack, and a heat dissipation method.

Abstract

This application discloses an air intake assembly for a fuel cell stack, a fuel cell stack, and a heat dissipation method. The air intake assembly includes a flow field plate and a flow collector plate. The two opposite sides of the flow field plate are side I and side II, each with a flow path. The flow collector plate includes a first flow collector plate and a second flow collector plate. The first flow collector plate cooperates with side I to form flow channel I, and the second flow collector plate cooperates with side II to form flow channel II. The air intake assembly of this application can ensure the uniformity of the stack temperature. At the same time, the dual-pump feeding structure design can reduce the working pressure of the air pump, which can have a positive effect on the selection of the air pump and the average distribution of material on each MEA in the stack. It also realizes the function of separate feeding and separate discharge of cathode air by dual pumps in the middle of the air-cooled high-temperature fuel cell stack.

Description

Technical Field

[0001] This application relates to an air intake component for a fuel cell stack, a fuel cell stack, and a heat dissipation method, belonging to the field of fuel cell technology. Background Technology

[0002] With the development of the fuel cell industry, the demand for fuel cell systems has increased dramatically. High-power-density fuel cell systems are widely used in various aspects of daily life and production, including stationary and mobile power stations to replace diesel generators, vehicle-mounted power supplies, and portable power supplies for individual soldiers. Fuel cell power generation systems have advantages such as low pollution, low fuel prices, low noise, and high power-density. Compared to gasoline and diesel generators, fuel cell operating temperatures are generally below 200°C, making them very safe for the environment and operators. In military equipment, due to their low operating temperature, low noise, and significantly lower heat radiation compared to gasoline and diesel generators, they can power military equipment with high stealth requirements.

[0003] The core challenge in high-power-density fuel cell systems is developing fuel cell stacks with high specific power, high consistency, and long lifespan. Stack reliability and consistency are key factors determining stack lifespan. The stack is the core component of the entire fuel cell system, and its reliability directly determines the overall reliability of the fuel cell system. High-temperature fuel cell stacks operate within a temperature range of 160℃ to 180℃. The stability of the stack's operating temperature directly affects its consistency and reliability, thus indirectly impacting its lifespan. During operation, the stack generates heat. If this heat is not promptly removed from the stack, its operating temperature will run off-limits beyond the normal operating range as the reaction time increases. Therefore, high-temperature fuel cell stacks require a coolant to remove the waste heat generated during operation and utilize it externally. Air-cooled stacks, with their unique air-cooling method, use air as both the cathode material and the cathode air as the coolant for transferring heat from the stack to the outside. Air-cooled fuel cell stacks are simple in structure, low in cost, and more reliable than stacks using other coolant heat dissipation methods, such as those using thermal oil as a coolant, because coolants are readily available and have low requirements for stack sealing.

[0004] Air-cooled high-temperature fuel cell stacks offer significant advantages, but air as a coolant also has limitations. Compared to liquid coolants like thermal oil, air has a lower heat capacity, meaning it can transfer less heat at the same flow rate. Therefore, as the power rating of air-cooled high-temperature fuel cell stacks increases, a larger flow rate of air is needed to remove more heat generated by the stack. Consequently, with the increase in power rating of air-cooled high-temperature fuel cell stacks, the requirements for the air pump in single-pump stacks become increasingly stringent. The air pump not only needs a larger flow rate, but also, with the increase in stack length, the pressure head of the air pump also needs to be higher. Existing air-cooled high-temperature fuel cell stacks have relatively simple cathode air intake methods, all using an air pump or air compressor as the cathode air source at one end of the stack endplate. As the stack length increases, this one-end air intake structure results in a greater air flow rate at the MEA (Medium-Energy Assemblage) near the air pump inlet than at the tail end of the stack. This structure causes uneven MEA temperature along the entire length of the stack, leading to significant differences in MEA performance under the same reaction conditions, resulting in poor stack performance consistency. Summary of the Invention

[0005] Based on the analysis and improvement of existing air-cooled high-temperature fuel cell structures, a dual-pump structure fuel cell stack with intermediate cathode feeding was invented. The stack structure includes two cathode and anode end plates with different structures, a stack cathode feeding plate, cathode and anode current collectors, two intermediate current collectors named intermediate current collector A and intermediate current collector B, an intermediate plate cathode inlet pipe, a cathode inlet cover plate and cathode left stack exhaust cover plates A and B, cathode right stack exhaust cover plates A and B, two stack insulation plates, 6 springs, and 6 screws.

[0006] One aspect of this application provides an air intake assembly for a fuel cell stack, the air intake assembly including a flow field plate and a flow collector plate;

[0007] The two opposite sides of the flow field plate are side I with flow paths and side II with flow paths, respectively.

[0008] The flow collector includes a first flow collector and a second flow collector. The first flow collector cooperates with side I to form flow channel I; the second flow collector cooperates with side II to form flow channel II.

[0009] The flow field plate has end A and end B;

[0010] The flow channel I flows from end A to end B;

[0011] The flow channel II flows from end A to end B;

[0012] On section I parallel to side I, the projections of the first gas flow channel and the second gas flow channel are centrally symmetrical about the intersection of the diagonals of section I.

[0013] The flow field plate is provided with an air inlet port and an air outlet port;

[0014] The air intake port is located at end A of side I and includes air intake I and air intake II; air intake I and air intake II are symmetrically arranged along the central axis of side I from end A to end B.

[0015] The air outlet includes an air outlet I located at end B on side I and an air outlet II located at end B on side II.

[0016] The air inlet I, the flow channel I, and the air outlet I are connected in sequence;

[0017] The air inlet II, flow channel II, and air outlet II are connected in sequence;

[0018] The first manifold is provided with a gas inlet I, which is connected to a gas outlet I;

[0019] The second manifold is provided with a gas inlet II, and the gas outlet II is connected to the gas outlet II.

[0020] Optionally, both flow channel I and flow channel II are serpentine flow channels.

[0021] Optionally, the air intake assembly for the fuel cell stack further includes a flow guiding unit I with a certain length for guiding airflow;

[0022] The length directions of the drainage unit I are free end I and free end II, respectively;

[0023] The flow guiding unit I is fixed to end B of the flow field plate. The free end I is used to guide the gas flowing out of the outlet I to flow away from the side II. The free end II is used to guide the gas flowing out of the outlet II to flow away from the side I.

[0024] The flow guiding unit I is integrated on the opposite side of the cathode air inlet (air inlet I and air inlet II) of the fuel cell stack as an air flow channel after the cathode air enters the fuel cell stack, so that the cathode air flows through the cathode flow channel on the graphite plate under the restriction of the cathode air cover.

[0025] Optionally, the flow field plate is made of 7075 aluminum alloy.

[0026] Optionally, end A of side I is provided with a through hole along the direction from side I to side II.

[0027] Another aspect of this application provides a fuel cell stack, the fuel cell stack including an air intake assembly, a limiting unit and a plurality of individual cells;

[0028] The limiting unit includes limiting unit I and limiting unit II;

[0029] The limiting unit I, the battery pack I composed of the single cells, the air intake assembly, the battery pack II composed of the single cells, and the limiting unit II are assembled sequentially to form the fuel cell stack;

[0030] The free end I of the drainage unit I is sealed to the limiting unit I; the free end II of the drainage unit I is sealed to the limiting unit II.

[0031] The air intake assembly is selected from the above-mentioned air intake assemblies for fuel cell stacks.

[0032] Optionally, the limiting unit I and the limiting unit II are respectively the male limit module and the female limit module.

[0033] The air intake assembly, limiting unit, battery pack I, and battery pack II are fastened together.

[0034] Optionally, the number of individual cells in battery pack I and battery pack II is the same.

[0035] Optionally, the fuel cell stack includes four guide plates of a certain length for guiding airflow; the two ends of the guide plates in the length direction are a fixed end and a free end, respectively;

[0036] The drainage plates are drainage plate a, drainage plate b, drainage plate c, and drainage plate d;

[0037] The fixed ends of the flow guide plate a, flow guide plate b, flow guide plate c, and flow guide plate d are respectively fixed to region a, region b, region c, and region d at end A of the flow field plate;

[0038] Regions a and c are arranged from end B to end A of the flow field plate and are located on both sides of the through hole.

[0039] Regions b and d are arranged from end B to end A of the flow field plate and are located on both sides of the through hole.

[0040] The diversion plate a has several through holes; the free end of the diversion plate a is fixed to the limiting unit I;

[0041] The free end of the drainage plate b is fixed to the limiting unit II;

[0042] The free end of the diversion plate c is fixed to the limiting unit I;

[0043] The free end of the drainage plate d is fixed to the limiting unit II.

[0044] Optionally, the limiting unit II is provided with exhaust hole I and exhaust hole II for discharging the airflow guided by the guide plate b and the guide plate d.

[0045] Optionally, each single cell includes a graphite plate and a membrane electrode assembly.

[0046] Optionally, the cathode limit switch module includes a cathode end plate, a PEEK insulating plate, and a cathode current collector that are sequentially fastened together from the outside to the inside.

[0047] The anode limit switch module includes a cathode end plate, a PEEK insulation plate, and an anode current collector plate that are sequentially fastened together from the outside to the inside of the fuel cell.

[0048] Optionally, a complete air-cooled high-temperature fuel cell stack is formed by clamping the graphite plate and membrane electrode assembly (MEA) between the anode and cathode end plates of the fuel cell stack and the cathode feed plate through six carbon steel screws.

[0049] Optionally, the cathode end plate of the fuel cell stack is made of aluminum alloy 7075;

[0050] The anode plate of the fuel cell stack is made of aluminum alloy 7075.

[0051] The cathode and anode end plates of the fuel cell stack serve as fixing plates at both ends of the entire fuel cell stack. They are made of 7075 aluminum alloy. Six metal springs are installed on the outside of the cathode end plate to counteract the changes in the length of the fuel cell stack caused by thermal expansion and contraction during operation, thereby ensuring that the fuel cell stack meets the requirements for sealing.

[0052] Optionally, the PEEK insulating plate is provided with through holes as channels for the flow of anode gas.

[0053] Optionally, the fuel cell stack further includes air pump I and air pump II;

[0054] The air pump I is connected to the air inlet I via a pipeline;

[0055] The air pump II is connected to the air inlet II via a pipeline.

[0056] As a specific implementation, the cathode intermediate plate of the fuel cell stack is also made of 7075 aluminum alloy. There are cathode air channels on both sides of the cathode feed intermediate plate. Each cathode air channel corresponds to an air pump. The two air pumps are responsible for the cathode feed of the left and right fuel cell stacks respectively.

[0057] In another aspect of this application, a heat dissipation method for a fuel cell stack is provided, the method comprising the above-described air intake assembly for a fuel cell stack or the above-described fuel cell stack.

[0058] Optionally, the specific method includes: air entering flow channel I and flow channel II through air inlet I and air inlet II of the air intake assembly respectively; the air entering flow channel I is guided into battery pack I through air outlet I, gas inlet I and flow guiding unit I; the air entering flow channel II is guided into battery pack II through air outlet II, gas outlet II and flow guiding unit II.

[0059] Air entering battery pack I is guided into guide plate d through the through holes of guide plate a and guide plate c, and discharged through exhaust hole II of limit unit II;

[0060] Air entering battery pack II is guided by the guide plate b and discharged through the exhaust port I of limit unit II.

[0061] The beneficial effects that this application can produce include:

[0062] The fuel cell stack provided in this application employs a center-feed structure for the cathode, which solves the problem of the central part of the stack having a higher temperature than the ends due to heat concentration during operation, thus helping to ensure temperature uniformity. Simultaneously, the dual-pump feeding design reduces the working pressure on the air pump, positively impacting pump selection and the even distribution of material on each MEA within the stack. It also enables the air-cooled high-temperature fuel cell stack to have separate central dual-pump feeding and separate cathode air discharge functions. Attached Figure Description

[0063] Figure 1 This refers to the dual-pump intermediate feed fuel cell stack in Embodiment 2 of this application;

[0064] Figure 2 This is an exploded view of the dual-pump intermediate feed fuel cell stack in Embodiment 2 of this application;

[0065] Figure 3 This is the cathode feed plate of the fuel cell stack in Embodiment 1 of this application; wherein Figure a is side view I and Figure b is side view II;

[0066] Figure 4 This refers to the current collector in Embodiment 1 of this application;

[0067] Figure 5 This refers to the cathode inlet shroud in Embodiment 1 of this application;

[0068] Figure 6 These are the left and right cathode stack exhaust hoods B in Embodiment 1 of this application;

[0069] Figure 7 Figure 1 shows the left and right cathode stack inlet shrouds A in Embodiment 1 of this application; where a is the right cathode stack inlet shroud A; and b is the left cathode stack inlet shroud A.

[0070] Figure 8 This refers to the anode plate of the fuel cell stack in Embodiment 2 of this application;

[0071] Figure 9 This refers to the anode current collector of the fuel cell stack in Embodiment 2 of this application;

[0072] Figure 10 This refers to the cathode end plate of the fuel cell stack in Embodiment 2 of this application;

[0073] Figure 11 This refers to the cathode current collector plate of the fuel cell stack in Embodiment 2 of this application;

[0074] Figure 12 This refers to the PEEK insulating board in Embodiment 2 of this application;

[0075] Figure 13 This refers to the cathode inlet pipe in Embodiment 2 of this application;

[0076] Figure 14 This refers to the screw in Embodiment 2 of this application;

[0077] Figure 15 This refers to the spring in Embodiment 2 of this application.

[0078] in:

[0079] 1. Cathode feed plate of fuel cell stack; 2. Current collector plate; 3. Cathode inlet hood plate of fuel cell stack; 4. Left and right exhaust hood plates B of cathode; 5. Left and right exhaust hood plates A of cathode; 6. Anode current collector plate of fuel cell stack; 7. PEEK insulation plate; 8. Anode end plate of fuel cell stack; 9. Cathode end plate of fuel cell stack; 10. Cathode current collector plate of fuel cell stack; 11. Cathode inlet pipe; 12. Screw; 13. Spring. Detailed Implementation

[0080] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0081] Example 1

[0082] This embodiment provides a specific air intake structure, including as follows: Figure 3 The cathode feed plate 1 shown is located on the left and right sides of the cathode feed plate. Figure 4 The manifold 2 shown Figure 5 The cathode inlet cover plate 3 of the fuel cell stack is shown.

[0083] The cathode feed plate 1 of the fuel cell stack is provided with a serpentine flow channel and an outlet I and an outlet II on both sides respectively. The left side of the cathode feed plate 1 of the fuel cell stack is provided with symmetrical inlets I and inlets II. The inlets I and inlets II are provided with mounting grooves and through holes. The cathode air inlet cover plate 3 of the fuel cell stack is located at the outlet I and outlet II ends, forming a flow channel that flows to both sides.

[0084] Example 2

[0085] This embodiment provides a fuel cell stack (such as...) Figure 2 As shown, it includes the air intake structure obtained in the embodiment.

[0086] The cathode end plate 9, PEEK insulation plate 7, cathode current collector plate 10, left graphite plate and MEA, current collector plate 2, cathode feed plate 1 (i.e., flow field plate), current collector plate 2, right graphite plate and MEA, anode current collector plate 6, PEEK insulation plate 7, and anode end plate 8 are sequentially integrated together using six carbon steel screws 12. Six springs 13 are installed on the outside of the cathode end plate 9. The six carbon steel screws pass through the springs and are secured to the entire fuel cell stack via nuts.

[0087] Two cathode air inlets are designed on the left side of the cathode feed plate 1. Two aluminum pipes are installed at each inlet to connect to two air pumps. The two aluminum pipes serve as cathode air inlet pipes 11, respectively responsible for the delivery of cathode material and cathode air coolant to the left and right fuel cells. The cathode air inlet cover plate 3 (i.e., the flow guiding unit I) is integrated on the opposite side of the cathode air inlet of the fuel cell stack, serving as the airflow channel after the cathode air enters the fuel cell stack. The cathode air is restricted by the cathode air inlet cover plate 3 and flows through the cathode flow channel on the graphite plate.

[0088] The cathode air carries away the heat generated by the MEA in the left and right fuel cell stacks through the cathode channels of the graphite plates. Meanwhile, the cathode air from the right stack is discharged outside the stack through the cathode right stack exhaust shroud A (i.e., guide plate b). The cathode air from the left stack is discharged outside the stack through the channel formed by the cathode left stack exhaust shroud A (i.e., guide plate a), the cathode left stack exhaust shroud B (i.e., guide plate c), and the cathode right stack exhaust shroud B (i.e., guide plate d). This achieves the function of separate feed and discharge of cathode air from the dual pumps in the middle of the air-cooled high-temperature fuel cell stack.

[0089] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An air intake assembly for a fuel cell stack, characterized in that, The air intake assembly includes a flow field plate and a flow collector plate; The two opposite sides of the flow field plate are side I with flow paths and side II with flow paths, respectively. The flow collector includes a first flow collector and a second flow collector. The first flow collector cooperates with side I to form flow channel I; the second flow collector cooperates with side II to form flow channel II. The flow field plate has end A and end B; The flow channel I flows from end A to end B; The flow channel II flows from end A to end B; On section I, which is parallel to side I, the projections of flow channel I and flow channel II are centrally symmetrical about the intersection of the diagonal of section I; The flow field plate is provided with an air inlet port and an air outlet port; The air intake port is located at end A of side I and includes air intake I and air intake II; air intake I and air intake II are symmetrically arranged along the central axis of side I from end A to end B. The air outlet includes an air outlet I located at end B on side I and an air outlet II located at end B on side II. The air inlet I, the flow channel I, and the air outlet I are connected in sequence; The air inlet II, flow channel II, and air outlet II are connected in sequence; The first manifold is provided with a gas inlet I, which is connected to a gas outlet I; The second manifold is provided with a gas inlet II, which is connected to the gas outlet II; Both flow channel I and flow channel II are serpentine flow channels; The air intake assembly for the fuel cell stack also includes a flow guiding unit I of a certain length for guiding airflow. The length directions of the drainage unit I are free end I and free end II, respectively; The flow guiding unit I is fixed to end B of the flow field plate. The free end I is used to guide the gas flowing out of the outlet I to flow in a direction away from the side II. The free end II is used to guide the gas flowing out of the outlet II to flow in a direction away from the side I. The flow field plate is made of 7075 aluminum alloy. The A end of side I is provided with a through hole along the direction from side I to side II.

2. A fuel cell stack, characterized in that, The fuel cell stack includes an air intake assembly, a limiting unit, and several individual cells; The limiting unit includes limiting unit I and limiting unit II; The limiting unit I, the battery pack I composed of the single cells, the air intake assembly, the battery pack II composed of the single cells, and the limiting unit II are assembled sequentially to form the fuel cell stack; The free end I of the drainage unit I is sealed to the limiting unit I; the free end II of the drainage unit I is sealed to the limiting unit II. The air intake assembly is selected from the air intake assembly for fuel cell stacks according to claim 1.

3. The fuel cell stack according to claim 2, characterized in that, The limiting unit I and limiting unit II are respectively the negative limit position module and the positive limit position module. The air intake assembly, limiting unit, battery pack I, and battery pack II are fastened together.

4. The fuel cell stack according to claim 3, characterized in that, Battery pack I and battery pack II have the same number of individual cells.

5. The fuel cell stack according to claim 4, characterized in that, The fuel cell stack includes four guide plates of a certain length for guiding airflow; the two ends of the guide plates in the length direction are a fixed end and a free end, respectively. The drainage plates are drainage plate a, drainage plate b, drainage plate c, and drainage plate d; The fixed ends of the flow guide plate a, flow guide plate b, flow guide plate c, and flow guide plate d are respectively fixed to region a, region b, region c, and region d at end A of the flow field plate; Regions a and c are arranged from end B to end A of the flow field plate and are located on both sides of the through hole. Regions b and d are arranged from end B to end A of the flow field plate and are located on both sides of the through hole. The diversion plate a has several through holes; the free end of the diversion plate a is fixed to the limiting unit I; The free end of the drainage plate b is fixed to the limiting unit II; The free end of the diversion plate c is fixed to the limiting unit I; The free end of the drainage plate d is fixed to the limiting unit II.

6. The fuel cell stack according to claim 5, characterized in that, The limiting unit II is provided with exhaust hole I and exhaust hole II, which are used to discharge the airflow guided by the guide plate b and the guide plate d.

7. The fuel cell stack according to claim 6, characterized in that, Each single cell includes a graphite plate and a membrane electrode assembly.

8. The fuel cell stack according to claim 6, characterized in that, The cathode limit switch module includes a cathode end plate, a PEEK insulating plate, and a cathode current collector plate that are sequentially fastened together from the outside to the inside. The anode limit switch module includes a cathode end plate, a PEEK insulation plate, and an anode current collector plate that are sequentially fastened together from the outside to the inside of the fuel cell.

9. The fuel cell stack according to claim 8, characterized in that, The cathode plate of the fuel cell stack is made of aluminum alloy 7075. The anode plate of the fuel cell stack is made of aluminum alloy 7075.

10. The fuel cell stack according to claim 8, characterized in that, The PEEK insulating plate has through holes to serve as channels for the flow of anode gas.

11. The fuel cell stack according to claim 2, characterized in that, The fuel cell stack also includes air pump I and air pump II; The air pump I is connected to the air inlet I via a pipeline; The air pump II is connected to the air inlet II via a pipeline.

12. A heat dissipation method for a fuel cell stack, characterized in that, The method includes the air intake assembly for a fuel cell stack as described in claim 1 or the fuel cell stack as described in any one of claims 2 to 11.

13. The heat dissipation method according to claim 12, characterized in that, Specifically, it includes: Air enters flow channel I and flow channel II through air inlet I and air inlet II of the air intake assembly, respectively. The air entering flow channel I is guided into battery pack I through air outlet I, gas inlet I and flow guiding unit I. The air entering the flow channel II is guided into the battery pack II through the air outlet II, the gas outlet II, and the flow guiding unit I; Air entering battery pack I is guided into guide plate d through the through holes of guide plate a and guide plate c, and discharged through exhaust hole II of limit unit II; Air entering battery pack II is guided by the guide plate b and discharged through the exhaust port I of limit unit II.

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