Proton exchange membrane fuel bipolar plate and cell stack manufacturing method
By directly filling water into the cathode and anode of the proton exchange membrane fuel cell and cooling through evaporation, the problems of complex cooling systems and water state fluctuations in the prior art are solved, and stable control and performance improvement of battery temperature are achieved.
Patent Information
- Application Number
- CN202510153254.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2025-06-10
AI Technical Summary
Existing proton exchange membrane fuel cells require complex system control during cooling, resulting in high cost and fluctuations in liquid and vapor water will affect battery performance.
The direct water injection evaporation cooling battery method is adopted to directly inject water into the anode of the battery, and remove the reaction heat through the evaporation of the water, simplifying the cooling system and reducing the need for coolant.
It realizes stable control of battery temperature, simplifies system control, reduces cost, and avoids fluctuations in liquid and steam water, improving battery performance.
Smart Images
Figure CN120127165A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an improved technology of perfluorosulfonic acid resin proton exchange membrane fuel cell, which is suitable for manufacturing bipolar plates and proton exchange membrane fuel cells for direct water injection evaporative cooling. Background Art
[0002] The proton exchange membrane fuel cell is a power generation device that uses hydrogen as the anode, oxygen or air as the cathode, a proton exchange membrane as the electrolyte, and a bipolar plate as a reaction container and conductive component to convert chemical energy into electrical energy. While the battery is generating electricity, it also generates heat during the chemical energy conversion process due to electrochemical polarization and resistance. In order for the fuel cell to generate electricity stably and reliably, it is necessary to maintain the battery power generation state, including controlling the temperature, pressure, humidity and flow of the power generation device. This requires the design of a bipolar plate with input and output reactants, products, and electrical and thermal conductivity functions. The bipolar plate structure includes a cathode cavity, an anode cavity, and a cooling cavity. Reasonable flow fields are set in the three cavities to form reactant and product channels and coolant heat dissipation channels. The bipolar plate material includes conductive and thermal conductive materials such as graphite and metal. The heat dissipation of proton exchange membrane fuel cells is mainly achieved by the coolant on the bipolar plate contacting the bipolar plate surface. The coolant absorbs heat and carries heat to conduct the heat of the battery reaction out of the battery, controlling the battery reaction temperature and the water balance in the battery. The perfluorosulfonic acid resin proton exchange membrane must be in a hydrated state to achieve the proton conduction function, that is, the electrolyte function. This requires that the battery contains a certain amount of liquid water. The battery temperature is controlled by using a coolant to cool the battery. The water in the battery presents a fluctuating form of liquid and vapor. If there is too much liquid, the battery will be flooded, that is, the electrode is covered with water, and the diffusion of the reactants is hindered. If there is too much vapor, the battery will evaporate. The proton exchange membrane loses water, causing proton conduction obstacles. At the same time, the reactant partial pressure will also decrease, resulting in a low reactant concentration and reduced battery performance. Therefore, using a coolant to cool the battery requires complex system control capabilities to control the humidification degree of the reactants and the coolant temperature, thereby increasing the cost of this power generation device. Summary of the invention
[0003] The present invention is a bipolar plate and a battery manufactured by directly injecting water to evaporate and cool the battery. The direct water injection evaporative cooling battery method is a method of directly injecting water into the anode and cathode of the battery to remove the heat of reaction by evaporation of water. This method does not require additional humidification of the reactants, and humidification of the anode and cathode reactants is achieved by direct water injection. In addition, since it is evaporative heat dissipation, the liquid water is vaporized, and the liquid water volume is inevitably reduced from the battery inlet to the outlet, and there will be no fluctuation between the liquid and vapor states. Since the phase change process of water carries a large amount of heat, the amount of water injected is much less than the coolant used in conventional bipolar plate batteries with cooling chambers. Therefore, water recovery and temperature control are simple and reliable. Therefore, the battery control system is simple. The bipolar plate and battery of the present invention are implemented in this way.
[0004] The bipolar plates are manufactured into A and B plates by stamping thin metal plates. The thin metal plates are stamped into bipolar plates with concave and convex flow fields. That is, the front and back sides of the A plate are the anode and cathode sides of the stack cells respectively, and the front and back sides of the B plate are the anode and cathode sides of another cell adjacent to the A plate in the stack. Additionally, the distribution plates are separately stamped and laser welded to the distribution areas on the anode and cathode surfaces of the A and B plates respectively. That is, the distribution plates are welded to the distribution areas of the A and B plates, with one side welded to the cathode surface and the other side welded to the anode surface. On the anode surface side, the A and B plates are directly welded to the distribution plates. On the cathode surface side, depressions are stamped in the corresponding distribution areas of the A and B plates, and the depth of the depression is the thickness dimension of the distribution plate. In this way, the flow fields in the distribution areas of the anode and cathode surfaces are of the same depth, without affecting the fluid state. The sealed cavity formed by the relative welding of the distribution plates and the A and B distribution areas is the water injection cavity. At the end of the flow field in the distribution area of the distribution plate, spaced micro flow fields are stamped, which are connected to the flow field in the distribution area, and the spaced flow fields are welded together. The A and B plates are stacked with the membrane electrode and the gasket, and the gasket seals the gas cavity of the bipolar plate to manufacture a proton exchange membrane fuel cell. That is, the A and B plates are attached with gaskets, and the battery cells are stacked in the form of "A + membrane electrode + B + membrane electrode + A + membrane electrode + B + membrane electrode". The battery features that the single plate realizes the function of the bipolar plate, without an external humidification system, and has a high power density of the stack and simple system control.
[0005] The structures of both the A and B bipolar plates include manifolds, channels, distribution area flow fields, flow fields, and sealing frames. The manifolds and channels are the inlets and outlets of the three - chamber fluid of the bipolar plate. The channels between the manifolds of the anode and cathode chambers of the bipolar plate and the distribution area flow fields are formed by the combination of stamping channels and narrow slots, and the channels between the water injection manifold and the water injection cavity are stamped.
[0006] On the distribution plate, manifolds, channels, and distribution area flow fields are stamped. The stamping direction of the concave and convex in the distribution area flow field is opposite to that of the distribution area flow fields of the A and B plates. At the end of the distribution area flow field, spaced micro flow fields are stamped or etched. The outlets of the micro flow fields are open, and the micro flow fields are welded to the A and B plates. The open micro flow fields correspond to the flow fields of the A and B plates, and the micro flow fields are connected to the water injection manifold of the water injection cavity to realize water injection into the flow field areas of the A and B plates. The channels between the manifolds of the anode and cathode chambers of the distribution plate and the distribution area flow fields are formed by the combination of stamping channels and narrow slots, and the channels between the water injection manifold and the water injection cavity are stamped.
[0007] The three - chamber manifolds of the distribution plate coincide with the manifolds of the A and B plates. The channels of the distribution plate between the three - chamber manifolds and their respective cavities correspond to the channels of the A and B plates. The narrow slots of the channels on one side (the anode or cathode side) are set on the distribution plate, and the narrow slots of the channels on the other side are respectively and correspondingly set on the A and B plates.
[0008] The flow field parts on the anode surfaces of the A and B plates are formed with concave and convex parts opposite to each other, being anti - symmetric structures. That is, the flow fields of the A and B plates are stamped with the same stamping parameters for the flow field and opposite flow field patterns. When the A and B plates are stacked, the flow fields support each other or cross each other to realize the conductive function of the bipolar plate.
[0009] On the anode side of the flow field in the A and B plate distribution areas, it is formed concave, and the distribution plate is welded to the anode distribution areas of the A and B plates. The flow field of the distribution plate is opposite to that of the A and B plate distribution areas, and the flow field of the distribution plate is convex. On the other side of the anode surface of the flow field in the A and B plate distribution areas, it is formed convex, and the distribution plate is welded to the cathode distribution areas of the A and B plates. The flow field of the distribution plate is opposite to that of the A and B plate distribution areas, and the flow field of the distribution plate is in the opposite direction.
[0010] The sealing frame is flat and can be processed with flanging patterns at the edges. A sealing gasket is attached to the sealing frame to isolate and seal the three cavities of the battery. The sealing gasket is processed by injection molding or compression molding processes, and the material is rubber, such as silicone rubber, ethylene propylene diene monomer rubber, etc.
[0011] The concave and convex parts of the upper and lower plates of the flow field of the A and B plates are in the middle of the plate surface of the sealing frame, that is, the protruding part of the flow field is higher than the sealing frame, and the concave part of the flow field is lower than the sealing frame.
[0012] The membrane electrode assembly (MEA) is formed by laminating the FRAME and GDL (CCM). The corresponding functional parts include the battery active area, the distribution area, and the sealing frame, which respectively correspond to the functional areas of the electrode plates. The battery active area is opposite to the flow field area of the electrode plate, the GDL is in contact with the flow field area, the distribution area is opposite to the distribution area of the electrode plate, and the frame is in contact with the flow field of the distribution area. Since there is no GDL layer in the anode and cathode distribution areas, while there is a GDL layer padded in the flow field area of the electrode plate, the thickness of the GDL layer can be used as a supplement to the increased part of the depth of the flow field in the distribution area. At the junction position between the distribution area and the flow field area, the GDL layer is biased towards the flow field side, that is, there is an appropriate distance between the GDL and the flow field of the distribution area, leaving a space for gas to enter the flow field and reducing the fluid resistance. Description of the Drawings
[0013] The following will further illustrate the above characteristics, technical features, advantages and their implementation manners of the present invention in a clear and understandable manner in combination with the drawings.
[0014] Figure 1 Exploded front view of the A plate
[0015] Figure 2 Exploded front view of the B plate
[0016] Figure 3 Exploded front view of the bipolar plate sealing structure
[0017] Figure 4 Exploded front view of the battery structure
[0018] Figure 5 Stacked cross-sectional schematic diagram of the battery structure
[0019] Figure 6 Cross-sectional view of a single cell with water injection
[0020] Figure 7Cross-sectional view of the reaction gas entering a single cell Detailed implementation manners
[0021] The bipolar plates are manufactured in two parts, namely Plate A and Plate B, by stamping thin metal plates.
[0022] Figure 1 It is a front view explosion diagram of the structure of Plate A, Figure 2 and it is a front view explosion diagram of the structure of Plate B.
[0023] The thin metal plates are stamped into bipolar plates with concave-convex flow fields. That is, the front and back of Plate A are the anode and cathode sides of the fuel cell stack respectively, and the front and back of Plate B are the anode and cathode sides of another fuel cell adjacent to Plate A in the stack. In addition, the distribution plates are separately stamped and laser welded to the distribution areas on one side of the anode surface of Plate A and the distribution areas on the cathode surface of the other side of the back respectively. The sealed cavity formed by the relative welding of the distribution plate and the distribution areas of Plate A and Plate B is the water injection cavity. Figure 1 (1) is the distribution plate, and the distribution plates are located at the distribution areas on the upper and lower sides of the plate respectively. (2) is Plate A or Plate B. Plate A and Plate B are stacked with the membrane electrode assembly (MEA) and gaskets to manufacture a proton exchange membrane fuel cell, as shown in Figure (5). That is, Plate A and Plate B are attached with gaskets, and "A + membrane electrode + B + membrane electrode" is used as the battery unit for stacking. The characteristics of the battery are that the single plate realizes the function of the bipolar plate, there is no external humidification system, the power density of the fuel cell stack is high, and the system control is simple.
[0024] Such as Figure 1 、 2 In it are the front view stamping diagrams of Plate A and Plate B. The structures of both Plate A and Plate B bipolar plates include manifolds (21, 22, 23), channels (210, 220, 230), distribution area flow fields (24), flow fields (25), and sealing frames. In the front view, the front is the anode surface. On one side, the periphery of the manifold is stamped and flanged towards the cathode side (2300), that is Figure 1 , and on the other side, the periphery of the manifold is stamped and flanged towards the anode surface. The manifolds and channels are the three-fluid inlets and outlets of the bipolar plate. The manifolds of the anode and cathode chambers of the bipolar plate and the channels of the distribution area flow fields are formed by the combination of stamping channels (210) and narrow slits (2300). The water injection channels are stamped and formed Figure 1 (220). The distribution area flow field (24) with the periphery of the manifold stamped and flanged towards the anode surface side is stamped concave, and the water injection channel (220) is convex dot matrix. The distribution area flow field with the periphery of the manifold stamped and flanged towards the cathode surface side is stamped convex, and the water injection channel is stamped concave. The manifolds (11, 12, 13), channels (110, 120, 130), and distribution area flow fields (14) are stamped on the distribution plate. The periphery of the manifold on the anode surface side of the distribution plate is stamped and flanged towards the anode side (1300), that is Figure 1, the periphery of the manifold is flanged and stamped upwards, and the periphery of the manifold on the cathode side of the distribution plate is stamped and flanged towards the cathode side. The manifold and the channels are the three-fluid inlets and outlets of the bipolar plate. The manifold of the cathode and anode chambers of the distribution plate and the flow field channels in the distribution area are formed by the combination of the stamping channel (110) and the narrow slit (1300). The water injection channel is formed by stamping. Figure 1 (220), the flow field (24) in the distribution area is stamped convex, and the bottom surface is in the same plane as the sealing frame of the distribution plate. The water injection channel (120) is a convex dot matrix, and the upper plane of the convex dots is in the same plane as the sealing frame.
[0025] Figure 1 , Figure 2 In [description], the three-chamber manifold of the distribution plate coincides with the manifolds of plates A and B, the channels of the distribution plate match the channels of plates A and B, the narrow slits of the channels on one side of the cathode and anode are arranged on the distribution plate, and the narrow slits of the channels on the other side are respectively arranged on plates A and B correspondingly.
[0026] Figure 3 In [description], the distribution plate stamps or etches spaced micro-protrusion flow fields (16) at the end of the flow field in the distribution area, corresponding to the flow fields of plates A and B. The laser welding lines between the protrusion flow fields separate the micro-flow fields (104) from each other. The outlets of the micro-protrusion flow fields are open. The cross-sectional scale of the micro-flow fields is controlled within 10 - 200 μm, and is selected according to the hydrophilicity and hydrophobicity of the materials of plates A, B and the distribution plate and the characteristics of the cathode and anode (the size of the micro-flow field stamping channel is determined according to the test results, and the theoretical calculation is not yet perfect), generally within 25 - 150 μm, which serves as the water injection holes of the present invention. The size design of the water injection holes has a certain wall-blocking effect on water. The water injection flow rate of the pore diameter formed by micro-flow field stamping or etching is controlled by the water injection pressure. The water injection pressure needs to overcome the gas pressure in the cathode and anode chambers and the resistance of the microporous solid wall to achieve water injection on the cathode and anode sides of the bipolar plate respectively.
[0027] Figure 1 , Figure 2 In [description], the flow fields on the anode surfaces of plates A and B are formed with concave and convex parts opposite to each other (25), which are anti-symmetric structures. That is, the flow fields of plates A and B are stamped with the same flow field stamping parameters and opposite flow field patterns. When plates A and B are stacked, the flow fields support or cross each other to achieve the conductive function of the bipolar plate.
[0028] Stamping is performed on the distribution areas of plates A and B. On one side of the anode surface, the anode distribution plate is welded. On the other side of the anode surface and on the cathode surface, the cathode distribution plate is welded. On the other side of the anode surface and on the cathode surface, at the position where the cathode distribution plate is welded, a protrusion (26) protruding from the anode surface towards the cathode and with the thickness of the cathode distribution plate is stamped. The cathode distribution plate is welded in the protrusion area. The flow fields in the anode distribution areas of plates A and B are recessed towards the cathode by stamping, serving as the cathode partition flow fields; the flow fields in the distribution areas of the distribution plates welded in the anode distribution areas are convex by stamping, serving as the anode distribution areas; the flow fields in the other distribution areas on the anode surfaces of plates A and B are convex by stamping, serving as the anode distribution area flow fields, and the flow fields in the distribution areas of the cathode distribution plates on the back are convex towards the cathode side by stamping, serving as the cathode distribution areas. The forming parameters of the flow fields in the anode and cathode distribution areas are the same. The distribution plates are welded on the distribution areas of plates A and B. See Figure 3 (103), the flow field of the distribution plate is opposite to the flow field of the distribution areas of plates A and B, and the flow field of the distribution plate is set to be convex.
[0029] Figure 3 、 4 In, the sealing frame is flat and can be processed with flanging patterns at the edges. A sealing gasket is attached to the sealing frame to isolate and seal the three cavities of the battery. The structure of the sealing gasket is divided into two types, one is the anode side and the other is the cathode side. The sealing gasket on the anode side has two thicknesses. One is around the periphery of the three-cavity manifold (101) on the distribution plate, and its thickness is thinner than that of the flow field sealing gasket (102). The thickness of the sealing gasket (202) on the cathode side is consistent. During battery assembly, the compression rate of the sealing gasket is the same.
[0030] The concave and convex parts of the flow field parts (25) of plates A and B are between the upper and lower plate surfaces of the sealing frame board surface, that is, the protruding parts of the flow field are higher than the sealing frame, and the recessed parts of the flow field are lower than the sealing frame.
[0031] Figure 4 In, the membrane electrode assembly MEA is composed of FRAME and GDL laminated. The corresponding functional parts include the battery active area, the distribution area, and the sealing frame, which correspond to the electrode plates respectively. The battery active area is opposite to the flow field of the electrode plate, GDL contacts the flow field, the distribution area is opposite to the distribution area of the electrode plate, and the frame contacts the flow field of the distribution area.
[0032] Figure 5 In, the battery stack is formed by stacking single cells "plate A + membrane electrode" and single cells "plate B + membrane electrode" in sequence into an electric stack. In the illustration, the upper and lower surfaces of the flow field parts of plate A or B are respectively higher and lower than the sealing frame. The sealing gaskets (201, 202) are located on the upper and lower sides of the electrode plate frame and correspond to the membrane electrode frame (FRAME) to seal the anode and cathode cavities of the battery.
[0033] There is no GDL layer in the distribution area of the A or B plate, while the GDL layer is padded in the flow field area of the electrode plate. The thickness of the GDL layer can be used as the increased part of the flow field depth in the distribution area. Therefore, the flow field depth in the distribution area is associated with the GDL thickness. Deepening the flow field is beneficial to reducing the fluid resistance of gas transportation; at the junction position between the distribution area and the flow field area, the GDL layer biases towards the flow field side, that is, there is a proper distance between the GDL and the flow field in the distribution area, leaving space for gas to enter the flow field and reducing the fluid resistance.
[0034] Figure 6 It is a schematic diagram of direct water injection into the battery. The water injection cavity channel is stamped on the side of the distribution plate and the water injection cavity manifold of the A or B plate close to the flow field in the distribution area. Multiple concave strip channels (120) are stamped on the flanged manifold of the distribution plate water injection cavity, and multiple convex strip channels (220) are stamped on the A or B plate. Deionized water is pumped from the water cavity manifold (12, 22), shown as path ① in the figure, through channels (120) and (220), shown as path ② in the figure, through the distribution area (14, 24) of the distribution plate and the A or B plate. The distribution flow fields of the distribution plate and the A or B plate cross each other to form a water flow channel, shown as path ③ in the figure, and then is injected into the anode flow field (25) through the micro-opening flow channel (16) in the distribution area, shown as path ④ in the figure. Through the purging of the reaction gas, liquid water is directly sprayed from the anode side to the GDL layer of the MEA. The water injection on the cathode side is similar to that on the anode side, and is injected into the cathode flow field (27) through the micro-opening flow channel (16) at the end of the distribution area flow field of the A or B plate, achieving the purpose of the present invention.
[0035] Figure 7 It is a schematic diagram of the gas cavity channel. Multiple convex dot strip channels (210) are stamped on the side of the anode manifold of the A or B plate close to the flow field in the distribution area. At the end of the flanged manifold of the distribution plate manifold (110), a narrow slit (1100) for the channel is punched on the side close to the flow field in the distribution area. Similarly, multiple concave dot strip channels (130) are stamped on the side of the cathode manifold of the distribution plate close to the flow field in the distribution area. At the end of the flanged manifold on the cathode side of the A or B plate, a side slit (2300) for the channel is punched on the side close to the flow field in the distribution area ( Figure 6 not shown). As Figure 6 , the anode gas is introduced from the anode manifold (11, 22) ①, passes through channels (110, 210) and the narrow slit (1100) on the distribution plate ②, and enters the anode flow field ③. The anode gas is mixed with the water sprayed into the distribution flow channel (16) and enters the anode reaction area, achieving the purpose of the present invention. Similarly, the cathode gas is mixed with the water sprayed into the distribution flow channel (16) and enters the cathode reaction area. The purpose of the water injection bipolar plate fuel cell of the present invention is achieved.
[0036] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the specific embodiments of the present invention.
Claims
1. The bipolar plate is made by thin metal plate stamping process, and is divided into A and B plates. The thin metal plate is stamped to form a bipolar plate with a concave and convex flow field, that is, the front and back of the A plate are the positive and cathode sides of the battery stack, respectively, and the front and back of the B plate are the positive and cathode sides of the other battery stack adjacent to the A plate. In addition, the distribution plate is stamped separately and laser welded on the distribution areas of the positive and cathode surfaces of the A and B plates, respectively, that is, the distribution plate is welded in the distribution areas of the A and B plates, one side is welded on the cathode surface, and the other side is welded on the anode surface. The distribution plate is directly welded to the A and B plates on the anode side, and the cathode side is stamped with a depression in the corresponding welded distribution area of the A and B plates. The depth of the depression is the thickness of the distribution plate. In this way, the flow fields of the distribution areas of the positive and negative poles are the same depth, which does not affect the fluid state. The sealed cavity formed by the relative welding of the distribution plate and the A and B distribution areas is a water injection cavity. The interval micro-flow field is stamped at the end of the flow field of the distribution area of the distribution plate, which is connected to the flow field of the distribution area, and the interval flow fields are welded. A and B plates are stacked with membrane electrode and sealing gaskets, and the sealing gaskets seal the air cavity of the bipolar plate to manufacture proton exchange membrane fuel cells. That is, the A and B plates are attached with sealing gaskets, and "A+membrane electrode+B+membrane electrode+A+membrane electrode+B+membrane electrode" is a battery unit for stacking and manufacturing. The battery features a single-pole plate that realizes the function of a bipolar plate, no external humidification system, high stack power density, and simple system control.
2. The structures of A and B bipolar plates include manifolds, channels, distribution area flow fields, flow fields and sealing frames. The manifolds and channels are the inlet and outlet of the three-chamber fluid of the bipolar plate. The manifolds of the anode and cathode chambers of the bipolar plate and the flow field channels of the distribution area are formed by combining stamping channels and narrow slits, and the channels between the water injection manifold and the water injection chamber are stamped.
3. The distribution plate is stamped with manifolds, channels, and distribution area flow fields. The stamping direction of the distribution area flow field is opposite to that of the distribution area flow field of the A and B plates. The end of the distribution area flow field is stamped or etched with a spacer micro-flow field. The outlet of the micro-flow field is open. The micro-flow fields are welded to the A and B plates. The open micro-flow fields correspond to the flow fields of the A and B plates. The micro-flow fields are connected to the water injection chamber manifold to realize water injection into the flow field area of the A and B plates. The distribution plate anode and cathode chamber manifolds and the distribution area flow field channels are formed by combining stamping channels and narrow slits, and the channels between the water injection manifold and the water injection chamber are stamped. The three-chamber manifold of the distribution plate coincides with the manifolds of the A and B plates, and the distribution plate channels of the three-chamber manifold and their respective cavities correspond to the channels of the A and B plates. The narrow slits of the channels on one side of the anode and cathode are arranged on the distribution plate, and the narrow slits of the channels on the other side are arranged on the A and B plates respectively.
4. The flow field parts of the anode surfaces of the A and B plates are formed with opposite concave and convex shapes, which are anti-symmetrical structures. That is, the flow fields of the A and B plates are punched with the same flow field punching parameters and opposite flow field patterns. When the A and B plates are overlapped, the flow fields support or cross each other to realize the conductive function of the bipolar plate.
5. One side of the anode surface of the flow field in the distribution area of the A and B plates is formed into a concave direction. The distribution plate is welded on the anode distribution area of the A and B plates. The flow field of the distribution plate is opposite to the flow field of the distribution area of the A and B plates, and the flow field of the distribution plate is convex. The other side of the anode surface of the flow field in the distribution area of the A and B plates is formed into a convex direction. The distribution plate is welded on the cathode distribution area of the A and B plates. The flow field of the distribution plate is opposite to the flow field of the distribution area of the A and B plates, and the flow field of the distribution plate is opposite to it.
6. The concave and convex upper and lower plate surfaces of the flow field parts of plates A and B are in the middle of the sealing frame plate surface, that is, the convex part of the flow field is higher than the sealing frame, and the concave part of the flow field is lower than the sealing frame.
7. The membrane electrode structure (MEA) is a superposition of FRAME and GDL (CCM), and the corresponding functional parts include the battery active area, distribution area and sealing frame, which correspond to the functional areas of the plate respectively. The battery active area is opposite to the plate flow field area, the GDL is in contact with the flow field area, the distribution area is opposite to the plate distribution area, and the frame is in contact with the distribution area flow field. Since there is no GDL layer in the anode and cathode distribution areas, and the plate flow field area is padded with a GDL layer, the GDL layer thickness can be used as a supplement to increase the depth of the distribution area flow field. At the junction of the distribution area and the flow field area, the GDL layer is biased to one side of the flow field, that is, the GDL is separated from the distribution area flow field by a suitable distance, leaving space for gas to enter the flow field and reduce fluid resistance.