CN210379269U - Bipolar plate of fuel cell - Google Patents

Abstract

A fuel cell bipolar plate comprises a first polar plate and a second polar plate, wherein the first polar plate and the second polar plate have the same structure; the two polar plates comprise gas flow channels, ribs, a first plane, a second plane and a third plane; the first plane is a reference surface of the metal polar plate, the first plane comprises a gas transition area and a sealing ring plane, the second plane is a gas runner bottom plane, the second plane is higher than the first plane, and the entrance of gas entering the runner from the transition area is in a step shape; when the two polar plates are buckled, an interlayer is formed between the bottom planes of the two gas flow channels and provides a flow channel for cooling liquid; each gas flow passage of the polar plate further comprises a cylindrical recess and a hemispherical bulge, and the circle centers of the cylindrical recess and the hemispherical bulge are uniformly distributed on the central axis of the gas flow passage at intervals.

Description

Bipolar plate of fuel cell

Technical Field

The utility model belongs to the fuel cell field, concretely relates to metal bipolar plate structure in fuel cell pile and coolant passage field among this fuel cell.

Background

Starting from the industrial revolution, clean, inexpensive energy sources are increasingly the driving force for the world's increasingly lush and economic development. Traditional energy sources such as petroleum, coal and natural gas have increasingly remarkable influence on the environment in the use process, and the energy sources belong to limited energy sources, and the unlimited use can accelerate the exhaustion of earth energy sources. In the face of these problems, the development of fuel cell technology has been a breakthrough in recent years, the use of fuel cells in the world has also entered a new stage, and fuel cells are used for power supply in the fields of automobiles, aerospace, and the like.

The bipolar plate is one of the core components of a fuel cell, accounting for 80% of the mass of the stack and 45% of the cost. The bipolar plate has a plurality of important functions of conducting current, supporting a membrane electrode, uniformly conveying and isolating reaction gas, circulating cooling liquid, quickly dissipating heat and the like.

At present, the flow field forms of the bipolar plate also have various forms, including parallel flow channels, interdigital flow channels, serpentine flow channels, reticular flow fields, dot flow fields and the like. The proper flow channel structure in the bipolar plate is beneficial to discharging water so as to improve the flooding condition, so that the concentration of reactants in the whole flow field is uniformly distributed, the local overheating is avoided, and the performance of the fuel cell is improved.

The bipolar plate materials widely used in proton exchange membranes are divided into three types: graphite materials, metal materials, composite materials. The graphite bipolar plate has good electrical conductivity, thermal conductivity, stability and corrosion resistance, but has relatively poor mechanical properties, brittleness, difficult machining and high cost, and the graphite bipolar plate stack has heavy weight. The metal bipolar plate has good conductivity, light weight and low cost, but the complex structure of the metal bipolar plate affects the assembly quality and the battery performance and is limited by the forming process of the metal bipolar plate at present, although the bipolar plate with the complex structure can solve the problem of drainage and improve the battery efficiency, the processing difficulty is large, and meanwhile, the cost of the bipolar plate can be improved due to the higher precision requirement.

The utility model discloses a chinese utility model patent (application number 201910330023.1) discloses a fuel cell polar plate and fuel cell, fuel cell polar plate package rubbing board body, it is protruding including first strip in the first face of plate body, the bellied extending direction of first strip is cross arrangement with gas flow channel's extending direction for gas flow channel becomes concave-convex structure, and the vortex operation when reinforcing gas flow improves reaction efficiency, reduces polar plate length. The precondition for facilitating the drainage proposed by the patent is that the placing direction of the fuel cell is required (the flow direction of the reaction gas is vertical, the flow direction is from top to bottom, if the reaction gas is placed horizontally, flooding is easy to occur, and water generated in the flow channel is easy to gather at the bottom of the concave-convex flow channel); the patent requires that the metal plate is processed in two directions, and the punching processing of the intersection of the double flow channels can cause the radius of the chamfer to be larger, thereby affecting the flow channel structure and the strength of the whole fuel cell and further affecting the performance of the cell. The flow channel type cooling liquid is influenced by the size of a cooling liquid flow channel, the required flow speed is small, the cooling efficiency is low, the pressure can be increased if the flow speed is increased, the strength of the metal plate is high due to the fact that the internal structure is complex, otherwise, the metal plate can deform, and the performance of the battery is influenced.

In summary, there is a need for a multifunctional metal dual plate that can not only enhance the turbulent flow operation of the gas flow, but also avoid flooding, has no limitation on the placement of the dual plate, and provides a channel for the coolant, and has a simple structure and low processing difficulty.

SUMMERY OF THE UTILITY MODEL

Based on this, in order to solve the technical problem who exists among the background art, the utility model discloses an aim at improves the drainage performance of negative plate runner when taking into account fuel cell power density and promoting to and provide the process degree of difficulty that simplifies the polar plate structure and reduce the metal sheet processing when the coolant liquid intermediate layer in metal bipolar plate, improve bipolar plate self intensity, thereby reach and make the higher more stable of pile efficiency.

The utility model aims at designing a can improve the runner type of current density and be favorable to the discharge of product water at the negative plate, when not influencing the improvement of current density, design the runner and make two polar plates close to form the intermediate layer when bipolar plate and supply the coolant liquid to pass through, reduce the temperature of galvanic pile.

A fuel cell bipolar plate comprises a first polar plate and a second polar plate, wherein the first polar plate and the second polar plate have the same structure; the two polar plates comprise gas flow channels, ribs, a first plane, a second plane and a third plane; the first plane is a reference surface of the metal polar plate, the first plane comprises a gas transition area and a sealing ring plane, the second plane is a gas runner bottom plane, the second plane is higher than the first plane, and the entrance of gas entering the runner from the transition area is in a step shape; when the two polar plates are buckled, an interlayer is formed between the bottom planes of the two gas flow channels and provides a flow channel for cooling liquid; each gas flow channel of the polar plate also comprises a cylindrical recess and a hemispherical bulge, and the circle centers of the cylindrical recess and the hemispherical bulge are uniformly distributed on the central axis of the gas flow channel at intervals; the third plane is the top surface of the runner rib and is also the upper end surface of the polar plate, the third plane is higher than the upper vertex of the hemispherical bulge, and the spherical radius of the hemispherical bulge is smaller than the width of the gas runner, so that water generated in the cathode runner is discharged from two sides of the hemispherical bulge.

Preferably, the difference in height between the second plane and the first plane is set to 1/10 the total thickness of the plate.

Preferably, the height of the hemispherical protrusions in the gas flow channel is slightly lower than the height of the gas flow channel ribs.

Preferably, the third plane of the bottom end plane of the cylindrical depression in the gas channel is parallel to the first plane at the inlet.

Preferably, the centers of the hemispherical protrusions and the cylindrical depressions in the gas flow channel are located on the center line of the flow channel width.

Preferably, the cylindrical diameter of the cylindrical recess in the gas flow channel is less than 3/4 and greater than 1/2 of the flow channel width.

Preferably, the first polar plate and the second polar plate with the same structure are superposed and superposed with the second polar plate after rotating around the long edge, and the bottoms of the cylindrical concave structures of the two polar plates are mutually contacted and superposed.

Preferably, two adjacent air inlets are arranged at intervals, and two adjacent air outlets are arranged at intervals.

Preferably, the pole plate is made and formed by a metal or alloy sheet with the thickness of less than 0.5mm through a pressing method.

The utility model provides a fuel cell polar plate, the first plane of polar plate and the planar difference in height of second make two polar plates form intermediate layer behind the synthetic bipolar plate, and interbedded region supplies the coolant liquid to pass through, and the cylinder sunk structure in the runner provides the structural support for the intermediate layer, avoids the polar plate deformation that the intermediate layer space arouses. The hemispherical bulges in the flow channel increase the turbulence effect, so that the gas can react more fully in the flow channel, the power density is improved, meanwhile, product water generated on the side of the cathode plate can flow away from gaps on two sides of the hemispherical bulges, the discharge of the water is facilitated, and the flooding is avoided. The flow direction cross-section of coolant liquid to the runner is area type flow direction, with reaction gas runner and abundant contact, and area of contact is big, and the heat quantity that water flow was taken away greatly is high, and the cooling effect is excellent, and the cylinder is sunken to make the coolant liquid pressure in the intermediate layer more even, has played the effect of fluid disturbance to the coolant liquid in the coolant liquid passageway, and temperature distribution is more even simultaneously.

Drawings

Fig. 1 is a schematic perspective view of a fuel cell plate according to the present invention;

fig. 2 is a partially enlarged view of a portion a of fig. 1 of the fuel cell electrode plate of the present invention;

fig. 3 is an exploded view of the structure of a bipolar plate for a fuel cell according to the present invention;

figure 4 is a perspective cross-sectional view of a fuel cell bipolar plate of the present invention;

fig. 5 is a partially enlarged view of a portion B in fig. 4;

FIG. 6 is a front view of a fuel cell bipolar plate;

FIG. 7 is a cross-sectional view in the direction C-C of the bipolar plate of the fuel cell of FIG. 6;

fig. 8 is a partial enlarged view E of fig. 7;

FIG. 9 is a cross-sectional view in the direction D-D of the bipolar plate of the fuel cell of FIG. 6;

fig. 10 is a partial enlarged view F in fig. 8;

fig. 11 is a partial enlarged view G in fig. 8;

fig. 12 is a partial enlarged view H in fig. 8;

fig. 13 is a partial enlarged view I in fig. 6.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The utility model provides a bipolar plate, which comprises two unipolar plates, wherein one side of the unipolar plate is a flow field runner, the other side of the unipolar plate enables an interlayer to be arranged in the middle of the bipolar plate after the bipolar plate is synthesized by a stepped structure, and a cylinder is sunken to provide a supporting function for the middle area of the bipolar plate after the bipolar plate is synthesized by the two bipolar plates, thereby ensuring the strength of the bipolar plate and preventing the deformation of the bipolar plate; the hemispherical bulge is arranged in the middle of the flow channel of the polar plate, the turbulence effect of reaction gas is increased, the reaction efficiency is improved, and product water formed in the negative plate flows away from two sides of the hemispherical bulge, so that the water flooding is prevented, and the placement of a fuel cell stack is not limited.

The utility model provides a bipolar plate, one side of a single polar plate is a flow field runner, the other side of the single polar plate enables an interlayer to be arranged in the middle of the bipolar plate after the bipolar plate is synthesized by a ladder structure, and a cylinder is sunken to provide a supporting function for the middle area of the bipolar plate after the bipolar plate is synthesized by two polar plates, thereby ensuring the strength of the bipolar plate and preventing the deformation of the polar plate; the hemispherical bulge is arranged in the middle of the flow channel of the polar plate, the turbulence effect of reaction gas is increased, the reaction efficiency is improved, and product water formed in the negative plate flows away from two sides of the hemispherical bulge, so that the water flooding is prevented, and the placement of a fuel cell stack is not limited.

As shown in fig. 1-2, which is an embodiment of the present invention, the present invention provides a fuel cell bipolar plate, including a polar plate 1 and a polar plate 2, wherein the polar plate 1 and the polar plate 2 have the same structure; both the two plates comprise a gas flow channel 25, ribs 26, a first face 11, a second face 12 and a third face 13; the first surface 11 is a reference surface of the metal polar plate, the first surface 11 comprises a gas transition area 24 and a sealing ring plane 23, the second surface 12 is a bottom plane of a gas flow channel, the second surface 12 is higher than the first surface 11, the height difference between the second surface 12 and the first surface 11 is set to be 1/10 of the whole thickness of the polar plate 1, and the inlet of the gas entering the flow channel from the transition area 24 is in a step shape; when the two polar plates are buckled, an interlayer is formed between the bottom planes of the two gas flow channels, and the interlayer 27 provides a flow channel for cooling liquid; each gas flow channel 25 of the polar plate also comprises a cylindrical recess 15 and a hemispherical bulge 14, and the circle centers of the cylindrical recess 15 and the hemispherical bulge 14 are uniformly distributed on the central axis of the gas flow channel 25 at intervals; the third plane 13 is the top surface of the flow channel rib and is also the upper end surface of the polar plate, the third plane 13 is higher than the upper vertex of the hemispherical protrusion 14, the spherical radius of the hemispherical protrusion 14 is smaller than the width of the gas flow channel 25, so that the water generated in the cathode flow channel is discharged from the two sides of the hemispherical protrusion 14.

As shown in fig. 3, after one of the two identical plates 1 and 2 rotates 180 ° around the long side of the plate, the two plates are overlapped, and the inlets 18 of the two plates are staggered with each other, the inlet of the cathode plate is fed with oxygen, the inlet of the anode plate is fed with hydrogen, and the outlets 19 of the two plates are also staggered with each other; meanwhile, the cooling liquid channel structure between the two polar plates is matched to form a complete channel.

As shown in fig. 4, since the second plane 12 is higher than the first plane 11, when the two electrode plates are combined, a gap exists between the two electrode plates, the height of the gap is 2 times of the height difference between the second plane 12 and the first plane 11, and the height of the gap can be adjusted by the step height, and at the same time, the pressure of the cooling liquid passing through the cooling liquid channel can be reduced, and the metal plate is prevented from being deformed due to too high pressure.

As shown in fig. 5, after the two polar plates are combined, the cylindrical depressions 15 are overlapped and contacted with each other, so that the supporting force between the two polar plates is increased, the overall strength of the fuel cell and even the electric pile is enhanced, the metal bipolar plate is prevented from being deformed due to extrusion in the assembling process, the proton exchange membrane is prevented from being stressed unevenly, and the pulling force is increased to damage the proton exchange membrane; the cylindrical depressions 15 exert uniform stress on the fuel cell, protect the proton exchange membrane, and increase the overall structural strength of the fuel cell.

As shown in fig. 5, the cylindrical recesses 15 and the hemispherical protrusions 14 are distributed in a staggered manner, so that the gas concentration distribution is more uniform, the gas flow length is increased, and the reaction efficiency is increased.

As shown in fig. 6, the gas inlet 18 and the gas outlet 19 are arranged in a staggered manner, so that the path of the gas can be extended, the reaction efficiency can be increased, the gas moves in a vertical direction (shown in the way), and in the actual case, due to the special design of the flow channel, the flow channel is not limited to be placed, and can be placed vertically or horizontally.

As shown in fig. 6, coolant inlets 16 and coolant outlets 17 are provided at opposite ends of the bipolar plate across the gas flow channels, with the gas flow direction being perpendicular to the coolant flow direction.

As shown in fig. 7 and 8, the flow direction section 20 of the cooling liquid is in an area type flow direction, the flow channel is in full contact with the reaction gas flow channels 21 and 22, the contact area is large, the heat quantity taken away by the water flow is high, the cooling effect is excellent, the pressure of the cooling liquid in the interlayer is more uniform due to the cylindrical depression, the fluid disturbance effect is realized on the cooling liquid in the cooling liquid channel, and the temperature distribution is more uniform.

As shown in fig. 8, the height of the hemispherical protrusions 14 in the flow channel is slightly lower than the third plane 13 on the top surface of the flow channel rib, so as not to contact with the proton exchange membrane, and the reaction area of the fuel gas and the membrane is increased; the arrow moving direction is the local motion track of gas in the runner, and when meeting hemispherical bulge 14, the gas flow changes, and gas need cross hemispherical bulge 14 or flow from both sides, increases gaseous perturbance to improve reaction efficiency, strengthen the battery performance.

As shown in fig. 8, the hemispherical protrusions 14 in the flow channel are symmetrically positioned with the cylindrical recesses 15, the cylindrical recesses 15 are overlapped and contacted with each other, and the supporting surface of the middle region of the two polar plates is the circular bottom surface of the cylindrical recess 15.

As shown in fig. 9, the direction of the arrows is the flow direction of the coolant D-D, and the coolant enters the interlayer of the bipolar plate from the coolant inlet 16, flows in the interlayer of the bipolar plate in the direction of the arrows, and finally is discharged from the outlet 17; in particular, the direction of the cooling liquid entering the inlet and the direction of the cooling liquid discharging the outlet can be the same direction or different directions.

As shown in fig. 10, the direction of the arrow is the flow direction of the cooling liquid at the inlet portion.

As shown in fig. 11, the direction of the arrows is the direction of coolant flow in the bipolar plate sandwich.

As shown in fig. 12, the direction of the arrow is the flow direction of the cooling liquid at the outlet portion.

As shown in fig. 13, the water generated in the cathode plate is discharged by flowing in the direction indicated by the arrow, the product horizontally passes through the cylindrical recess 15 and then passes through both sides of the hemispherical protrusion 14, which facilitates the discharge of the product water while increasing turbulence, and if water is generated on the surface of the hemispherical protrusion 14, the water also slides down the bottom of the flow channel from the hemispherical arc surface due to the hemispherical arc structure, thus flowing out.

The utility model provides a pair of fuel cell bipolar plate is verified through professional simulation software, is favorable to fuel cell's performance to promote, compares and promotes nearly 10% in traditional direct current way performance to from the polar plate distribution condition of product water, water concentration global distribution also is less than traditional direct current, and temperature distribution is more even for traditional direct current way.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (7)

1. A fuel cell bipolar plate, comprising: the structure of the first pole plate and the second pole plate is the same; the two polar plates comprise gas flow channels, ribs, a first plane, a second plane and a third plane; the first plane is a reference surface of the metal polar plate, the first plane comprises a gas transition area and a sealing ring plane, the second plane is a gas runner bottom plane, the second plane is higher than the first plane, and the entrance of gas entering the runner from the transition area is in a step shape; when the two polar plates are buckled, an interlayer is formed between the bottom planes of the two gas flow channels and provides a flow channel for cooling liquid; each gas flow channel of the polar plate also comprises a cylindrical recess and a hemispherical bulge, and the circle centers of the cylindrical recess and the hemispherical bulge are uniformly distributed on the central axis of the gas flow channel at intervals; the third plane is the top surface of the runner rib and is also the upper end surface of the polar plate, the third plane is higher than the upper vertex of the hemispherical bulge, and the spherical radius of the hemispherical bulge is smaller than the width of the gas runner, so that water generated in the cathode runner is discharged from two sides of the hemispherical bulge.

2. A fuel cell bipolar plate as in claim 1, wherein the difference in height between the second plane and the first plane is set to 1/10 the total thickness of the plate.

3. A fuel cell bipolar plate as in claim 2 wherein the hemispherical protrusions in said gas flow channels are slightly lower in height than the height of said gas flow channel ribs.

4. A fuel cell bipolar plate as in claim 2, wherein said hemispherical protrusions and cylindrical depressions in said gas flow channels are centered on the centerline of the width of the flow channels.

5. A fuel cell bipolar plate as in claim 2 wherein the cylindrical diameter of said cylindrical depressions in said gas flow channels is less than 3/4 and greater than 1/2 of the channel width.

6. The bipolar plate of claim 1, wherein the first and second plates have the same structure, and the first plate rotates around the long side and overlaps with the second plate, and the bottoms of the cylindrical recesses of the two plates contact with each other and overlap with each other.

7. A fuel cell bipolar plate as in claim 1, wherein said plate is formed by pressing a metal or alloy sheet having a thickness of less than 0.5 mm.

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