An air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends

Abstract

The present invention belongs to the technical field related to proton exchange membrane fuel cells, and discloses an air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends. The cathode plate is provided with a longitudinal corrugated flow channel, and the two ends of the longitudinal corrugated flow channel are provided with hydrogen inlet / outlet corresponding to the inlet / outlet on the anode plate. The outer side of the hydrogen inlet / outlet is provided with corrugated heat dissipation ribs, and the flow channel direction on the heat dissipation rib is consistent with the direction of the longitudinal corrugated flow channel. Air enters the longitudinal corrugated flow channel and the heat dissipation rib to take away the heat of the metal bipolar plate, thereby achieving air cooling; the anode plate is provided with a transverse corrugated flow channel, and the hydrogen inlet / outlet is provided on both sides of the transverse flow channel. The hydrogen enters and flows out from the hydrogen inlet / outlet. Through the present invention, the heat dissipation problem of medium-power air-cooled fuel cells is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to proton exchange membrane fuel cells, and more specifically, relates to an air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends. Background Art

[0002] Proton exchange membrane fuel cells convert hydrogen and oxygen directly into electricity, water and waste heat through redox reactions. The electrochemical reaction in the fuel cell needs to be carried out at a suitable temperature, so the heat generated during the reaction needs to be discharged in a timely manner. Fuel cells can be divided into two types: water-cooled and air-cooled by cooling method.

[0003] Air-cooled fuel cells use fans to blow in air to remove the accumulated heat in the stack. Liquid-cooled fuel cells have reserved cooling channels, and the coolant is pumped into the stack for circulation through a coolant pump to remove the heat in the stack. The coolant is generally a non-conductive liquid with large heat capacity, low viscosity, low cost, and has a much better cooling effect than air. However, the bipolar plates have reserved cooling channels and coolant circulation loops, and the cooling pump and radiator greatly increase the volume of the stack system, thus limiting its application in scenarios with high requirements for volume and quality, such as portable mobile power supplies, drones, and unmanned ships.

[0004] CN201721485943.3 embeds the heat sink into the flow channel of the metal cathode plate, and increases the cooling area through the heat sink to achieve the purpose of increasing the heat dissipation. The air-cooled fuel cell bipolar plate designed to enhance the heat dissipation effect is complex in structure, and it is necessary to insert corrugated heat sinks before assembling the anode and cathode, which increases the manufacturing cost; CN202110819986.5 discloses an air-cooled proton exchange membrane fuel cell metal bipolar plate, which achieves the effect of improving the reaction rate of the fuel cell by designing a buffer flow channel, a diverter column and a diverter groove at the hydrogen inlet and outlet. This patent only focuses on improving the distribution of hydrogen gas flow inlet and outlet, and does not pay attention to the cathode heat dissipation problem of air-cooled fuel cells. CN201911217398.3 discloses an air-cooled fuel cell graphite bipolar plate, which makes hydrogen and oxygen evenly distributed at the two poles by designing the cross flow channel of the anode and cathode. The two graphite monopolar plates of the anode and cathode are designed to fit together to form a bipolar plate. The anode inlet and outlet are designed with spoiler columns to strengthen the hydrogen flow disturbance to achieve the purpose of even hydrogen distribution. However, graphite bipolar plates are solid structures, heavy in weight, and made of brittle materials, which limits their application in scenarios with large vibration amplitudes.

[0005] In order to solve the heat dissipation problem of medium-power air-cooled fuel cells, a structure with corrugated plate heat dissipation ribs at both ends of the cathode based on metal stamping bipolar plates is proposed. The heat dissipation ribs at both ends are stamped into one piece with the cathode plate, and the anode and cathode plates are welded at the hydrogen inlet and outlet. The proposed bipolar plate has a simple structure, low cost, does not increase the complexity of the system, and improves the heat dissipation performance of air-cooled fuel cells. Summary of the invention

[0006] In view of the above defects or improvement needs of the prior art, the present invention provides an air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends to solve the heat dissipation problem of medium-power air-cooled fuel cells.

[0007] To achieve the above object, according to the present invention, there is provided an air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends, the metal bipolar plate comprising a cathode plate and an anode plate, wherein:

[0008] The cathode plate is provided with a longitudinal corrugated flow channel, and hydrogen inlets / outlets are provided at both ends of the longitudinal corrugated flow channel, corresponding to the inlets / outlets on the anode plate. Corrugated heat dissipation ribs are provided on the outside of the hydrogen inlets / outlets, and the flow channel direction on the heat dissipation ribs is consistent with the direction of the longitudinal corrugated flow channel. Air enters the longitudinal corrugated flow channel and the heat dissipation ribs to take away the heat of the metal bipolar plate, thereby achieving air cooling;

[0009] The anode plate is provided with a transverse corrugated flow channel, the hydrogen inlet / outlet is provided on both sides of the transverse flow channel, and the hydrogen enters and flows out from the hydrogen inlet / outlet.

[0010] Further preferably, the width, depth and chamfer of the heat dissipation rib flow channel are consistent with the longitudinal corrugated flow channel on the cathode plate, and the heat dissipation rib and the cathode plate are formed in one piece.

[0011] Further preferably, the transverse flow channel on the anode plate is interrupted and divided into multiple flow channel ridges, and the gas is mixed and distributed at the segments.

[0012] Further preferably, the length of the flow channel ridge is 10 to 15 times the width of a single flow channel of the anode plate, and the width of the interruption interval is 1 to 2 times the width of a single flow channel of the anode plate.

[0013] Further preferably, the depth of the longitudinal corrugated flow channel is greater than the depth of the transverse corrugated flow channel.

[0014] Further preferably, the cathode plate and the anode plate are connected by welding. During welding, the hydrogen inlet / outlet of the anode plate corresponds to that of the cathode plate. The welding requires precise welding without air leakage.

[0015] Further preferably, the cathode plate and the anode plate are connected by welding, and during welding, the inlet / outlet of hydrogen on the cathode plate and the anode plate correspond to each other.

[0016] Further preferably, a gas sealing ring is provided at the inlet / outlet of the hydrogen to prevent gas leakage.

[0017] Further preferably, positioning holes are provided at the hydrogen inlet / outlet for positioning.

[0018] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0019] 1. The present invention provides an air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends. The heat dissipation ribs at both ends are stamped into one piece with the cathode plate, and the anode and cathode plates are welded at the hydrogen inlet and outlet. The proposed bipolar plate has a simple structure, low cost, does not increase the complexity of the system, and effectively solves the heat dissipation problem of medium-power air-cooled fuel cells;

[0020] 2. In the present invention, the stamping depth of the cathode flow channel is greater than that of the anode flow channel. On the one hand, the direction of the cathode flow channel is a longitudinal flow channel. On the other hand, the direction of the cathode flow channel is the same as the direction of the heat dissipation rib. Therefore, when the depth of the cathode flow channel is greater than that of the anode flow channel, it is beneficial for the cathode to supply air to discharge the accumulated heat in the battery stack.

[0021] 3. In the present invention, the cathode plate and the anode plate are connected by welding, and it is only necessary to ensure that the hydrogen inlet and outlet are sealed, and the gases in the cathode plate and the anode plate flow separately without interfering with each other. There is no requirement for side sealing, and the manufacturing process is simple;

[0022] 4. The flow channel on the anode plate of the present invention is interrupted into multiple flow channel ridges, and the width of the interrupted interval is slightly wider than the width of a single anode flow channel, which is convenient for the upstream gas to be fully integrated in the interval groove and flow into the next stage flow channel, so that the gas concentration in the adjacent hydrogen flow channels at the interruption is mixed, and the gas distribution of the entire flow field plate is more uniform. The setting of the intermittent flow channel prevents the long flow channel ridge of the anode plate from having poor contact with the membrane electrode during the bipolar plate assembly process, and can reduce the contact resistance between the bipolar plate and the membrane electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a cathode plate constructed according to a preferred embodiment of the present invention;

[0024] Figure 2 is a schematic structural diagram of an anode plate constructed according to a preferred embodiment of the present invention;

[0025] Figure 3 is a schematic structural diagram of a cathode plate and an anode plate after being assembled according to a preferred embodiment of the present invention;

[0026] Figure 4 is a schematic structural diagram of the air flow path of the cathode plate and the heat dissipation ribs constructed according to the preferred embodiment of the present invention;

[0027] Figure 5 It is a schematic structural diagram of the anode plate gas flow path constructed according to the preferred embodiment of the present invention.

[0028] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0029] 1- cathode plate, 2- anode plate, 3- hydrogen inlet / outlet, 4- heat dissipation ribs, 5- sealing ring on cathode plate, 6- sealing ring on anode plate, 7- interruption interval, 8- positioning hole, 9- bipolar plate after assembly, 10_1- welding sealing path, 10_2- general welding path, 11- side of bipolar plate after assembly, 12- air flow path in heat dissipation ribs, 13- air flow path in cathode flow channel, 14- gas flow path in anode flow channel. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The present invention aims to improve the heat dissipation capacity of bipolar plates of air-cooled proton exchange membrane fuel cells, and proposes an ultra-thin metal stamping bipolar plate for air-cooled proton exchange membrane fuel cells, comprising an anode plate welded up and down and a cathode plate with heat dissipation ribs.

[0032] like Figure 1 As shown, the cathode plate 1 has heat dissipation ridges extending from both ends to form a corrugated heat sink structure, the cathode flow channel adopts a trapezoidal direct flow channel, and the stamping lines of the heat sinks at both ends are consistent with the stamping lines of the flow channel. Preferably, the stamping chamfer of the stamped cathode flow channel is 15° to 30°, the stamping depth is 1mm to 1.8mm, the width is 1mm to 4mm, and the length of the single-side heat dissipation rib 4 is 50cm to 100cm.

[0033] like Figure 2 As shown, the anode plate 2 adopts a straight flow channel, and the hydrogen flow channel ridge is discontinuous. Several breakpoints are made on the flow channel ridge. The hydrogen is reintegrated and redistributed at the breakpoints along the flow direction, and flows into the anode flow channel of the next stage. Preferably, the stamping chamfer is 15° to 30° to facilitate stamping and demoulding. The flow channel ridge is interrupted at a preset length to form a transverse channel. The preset length is generally 10 to 15 times the width of a single flow channel, and the interruption interval 7 is 1 to 2 times the width of a single flow channel of the anode plate. The stamping depth of the anode flow channel is 0.6mm to 1mm, and the width is 0.5mm to 3mm.

[0034] Both the cathode plate and the anode plate are provided with hydrogen inlets / outlets. Hydrogen enters or flows out from the hydrogen inlet / outlet on the anode plate. The hydrogen inlet / outlet on the cathode plate is used to match the shape of the hydrogen inlet and outlet on the anode plate so that hydrogen can pass through the assembled bipolar plate smoothly. The sealing ring 5 and the sealing ring 6 ensure that the hydrogen flows in the anode flow channel.

[0035] like Figure 3 As shown, the welding sealing paths 10_1 and 10_2 on the bipolar plate 9 after assembly are shown in the figure. Precision welding is required at the hydrogen inlet / outlet 10-1 to ensure that the weld does not leak. General welding is required at 10_2 to connect the positive and negative plates to ensure that the bipolar plate connection does not bulge or warp. The metal stamping bipolar plate material is a stainless steel sheet with a thickness between 0.1mm and 0.2mm. When the stamping depth of the anode plate is shallow (0.7mm), a thinner stainless steel sheet, such as 0.1mm thick, is used. When the stamping depth of the cathode plate is deep (1.5mm), a 0.2mm thick stainless steel sheet is used. The cathode plate and the anode plate are combined by welding to ensure that the hydrogen inlet and outlet are sealed. The cathode flow field length of the bipolar plate is 80mm to 50mm; the anode flow field length is 500mm to 370mm.

[0036] like Figure 4 and 5 As shown, air is blown / sucked into the cathode flow channel and the heat dissipation channel by a fan, the air flow path 12 in the heat dissipation ribs is shown in the figure, and the air flow path 13 in the cathode flow channel is shown in the figure. The inlet / outlet of hydrogen on the cathode plate corresponds to the anode plate. When the stack is working, hydrogen enters the anode side through the inlet, and the hydrogen flow path 14 is shown in the figure.

[0037] In one embodiment of the present invention, the cathode plate 1 has an overall length of 500 mm and a width of 65 mm, that is, the cathode flow channel is 65 mm long, and the corrugated plate heat dissipation ribs 4 at both ends of the cathode plate extend out to a length of 50 cm. The cathode flow channel and the corrugated plate heat dissipation ribs are integrally formed by stamping, with a stamping depth of 1.5 mm, a stamping width of 3.2 mm, and a draft chamfer of 30°. To enhance the structural strength of the bipolar plate, the sharp corners are all rounded. The hydrogen inlet and outlet 3 adopts a trapezoidal structure to reserve the positions of the positioning holes 8 on both sides, and the sealing ring 5 on the cathode plate prevents hydrogen from leaking into the cathode flow channel area.

[0038] The overall length of the anode plate 2 is 400mm and the width is 65mm. The hydrogen adopts a straight channel. The second and third channels near the sealing ring are interrupted every 35mm or so. The hydrogen in the second and third channels is mixed and redistributed here to flow into the next stage. The hydrogen inlet and outlet and the positioning hole 8 adopt the same structure as the cathode plate hydrogen inlet and outlet 3 to ensure a close fit. The sealing ring 6 on the anode plate is sealed around the entire hydrogen flow area.

[0039] The air-cooled proton exchange membrane fuel cell ultra-thin metal stamping bipolar plate 9 with corrugated plate heat dissipation ribs at both ends needs to be tightly welded at the hydrogen inlet and outlet 8 at both ends 10_1, and welded at the air inlet and outlet 10_2 to tightly connect the anode and cathode bipolar plates. This completes the welding and assembly process of the cathode plate and the anode plate.

[0040] When assembling a stack using the bipolar plates of the present invention, in addition to installing a fan at the cathode inlet, additional cooling fans can be installed at the cooling ribs of the corrugated plates at both ends to achieve the purpose of enhanced heat dissipation.

[0041] In another embodiment of the present invention, the heat dissipation ribs at both ends can be lengthened to 100 cm. In use, the proton exchange membrane fuel cell is used by connecting multiple single cells in series to form a stack. When a small number of single cells are assembled, the fans at the heat dissipation ribs at both ends are omitted, and the extended ribs can be used as a radiator to expand the heat dissipation area of ​​the bipolar plate, and enhance the heat dissipation with the natural convection of the air in a large space. When a large number of single cells are assembled in the stack, the stack will generally overheat in the middle part of the battery. The heat dissipation enhanced bipolar plate of the present invention can be used in the middle of the stack, and a metal stamping bipolar plate of the same size without heat dissipation ribs can be used near the end plate to achieve the purpose of uniform temperature distribution in the stack.

[0042] In one embodiment of the present invention, if the battery stack needs to be used in a standing position (i.e., the anode air inlet is positioned higher and the air outlet is positioned lower), the heat dissipation ribs at both ends can be omitted to only one end (the cathode plate heat dissipation ribs face upward when used in a standing position), which does not affect the standing use of the battery stack, while retaining the corrugated plate heat dissipation ribs to enhance heat dissipation.

[0043] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends, characterized in that: The metal bipolar plate comprises a cathode plate and an anode plate, wherein: The cathode plate is provided with a longitudinal corrugated flow channel, and hydrogen inlets / outlets are provided at both ends of the longitudinal corrugated flow channel, corresponding to the inlets / outlets on the anode plate. Corrugated heat dissipation ribs are provided on the outside of the hydrogen inlets / outlets, and the flow channel direction on the heat dissipation ribs is consistent with the direction of the longitudinal corrugated flow channel. Air enters the longitudinal corrugated flow channel and the heat dissipation ribs to take away the heat of the metal bipolar plate, thereby realizing air cooling; the depth of the longitudinal corrugated flow channel on the cathode plate is greater than the depth of the transverse corrugated flow channel on the anode plate; The anode plate is provided with a transverse corrugated flow channel, the hydrogen inlet / outlet is provided on both sides of the transverse flow channel, and hydrogen enters and flows out from the hydrogen inlet / outlet.

2. An air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends as claimed in claim 1, characterized in that: The width, depth and chamfer of the heat dissipation rib flow channel are consistent with the longitudinal corrugated flow channel on the cathode plate, and the heat dissipation rib is integrally formed with the cathode plate.

3. The air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends as claimed in claim 2, characterized in that: The transverse flow channels on the anode plate are interrupted and divided into multiple flow channel ridges, and the gases are mixed and distributed at the segments.

4. The air-cooled fuel cell metal bipolar plate with corrugated heat dissipation ribs at both ends as claimed in claim 3, characterized in that: The length of the flow channel ridge is 10 to 15 times the width of a single flow channel of the anode plate, and the width of the interruption interval is 1 to 2 times the width of a single flow channel of the anode plate.

5. An air-cooled fuel cell metal bipolar plate with corrugated plate heat dissipation ribs at both ends as claimed in claim 1 or 2, characterized in that: The cathode plate and the anode plate are connected by welding, and during welding, the hydrogen inlets / outlets on the cathode plate and the anode plate correspond to each other.

6. An air-cooled fuel cell metal bipolar plate with corrugated heat dissipation ribs at both ends as claimed in claim 1 or 2, characterized in that: Gas sealing rings are provided at the hydrogen inlet / outlet to prevent gas leakage.

7. An air-cooled fuel cell metal bipolar plate with corrugated heat dissipation ribs at both ends as claimed in claim 1 or 2, characterized in that: The hydrogen inlet / outlet are both provided with positioning holes for positioning.

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