CN112436163A

CN112436163A - Metal bipolar plate and cathode closed air-cooled electric pile of fuel cell

Info

Publication number: CN112436163A
Application number: CN202011460709.1A
Authority: CN
Inventors: 贾古寨; 孙毅; 张伟; 白清友; 李郭威; 杜玮
Original assignee: Aerospace Hydrogen Energy Shanghai Technology Co ltd; Shanghai Institute of Space Power Sources
Current assignee: Aerospace Hydrogen Energy Shanghai Technology Co ltd; Shanghai Institute of Space Power Sources
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2021-03-02

Abstract

The invention discloses a fuel cell metal bipolar plate and a cathode closed air-cooled stack, comprising an anode plate, an air cooling plate and a cathode plate which are connected in sequence, and also includes a sealing ring for preventing gas leakage, the anode plate is far away from One side of the air cooling plate is provided with a fuel gas flow channel, and the fuel gas flow channel is arranged along the length direction of the metal bipolar plate; the side of the cathode plate away from the air cooling plate is provided with reaction air a flow channel, the reaction air flow channel is arranged along the length direction of the metal bipolar plate; the two sides of the air cooling plate are respectively provided with cooling air flow channels, and the cooling air flow channel is arranged along the metal bipolar plate width direction setting. The invention provides a fuel cell metal bipolar plate and a cathode closed air-cooled stack, which separates the reaction air channel and the heat dissipation air channel, and on the premise of ensuring the heat exchange efficiency, the large flow of cooling air will not cause the battery Severe drying increases battery life.

Description

Metal bipolar plate and cathode closed air-cooled electric pile of fuel cell

Technical Field

The invention relates to the field of fuel cells, in particular to a fuel cell metal bipolar plate and a cathode closed air-cooling electric pile.

Background

The air-cooled fuel cell uses hydrogen as fuel, a small amount of oxygen in air as oxidant, and the excessive air forcibly convects and cools the electric pile to keep the electric pile at normal working temperature (below 80 ℃). Water management is important to keep the fuel cell operating properly. Excessive moisture easily causes flooding of the porous diffusion electrode and hinders diffusion of gas; insufficient water content easily causes dehydration of the proton exchange membrane, and the ion conductivity is reduced. Both conditions severely affect the performance of the fuel cell. The air-cooled fuel cell cathode is open, and air passing through the flow channel not only participates in the cathode oxidation reaction, but also takes away a large amount of reaction heat. To achieve effective heat removal, very large air flow rates are required and the reaction stoichiometry is greater than 100. The water produced by the reaction is insufficient to saturate these large volumes of air, causing severe drying of the cell, affecting cell performance and durability.

Disclosure of Invention

The invention aims to provide a metal bipolar plate and a cathode closed air-cooling pile of a fuel cell, which separate a reaction air channel from a heat dissipation air channel, ensure the heat exchange efficiency, avoid the serious drying of the cell by large-flow cooling air and prolong the service life of the cell.

In order to achieve the aim, the invention provides a fuel cell metal bipolar plate which comprises an anode plate, an air cooling plate and a cathode plate which are sequentially connected, and further comprises a sealing ring for preventing gas leakage, wherein a fuel gas flow channel is arranged on one side of the anode plate, which is far away from the air cooling plate, and the fuel gas flow channel is arranged along the length direction of the metal bipolar plate;

a reaction air flow channel is arranged on one side of the negative plate, which is far away from the air cooling plate, and the reaction air flow channel is arranged along the length direction of the metal bipolar plate;

cooling air flow channels are respectively arranged on two sides of the air cooling plate and are arranged along the width direction of the metal bipolar plate;

one end of the metal bipolar plate is provided with an inlet which comprises a fuel gas inlet and a reaction air inlet; the other end is provided with an outlet which comprises a fuel gas outlet and a reaction air outlet;

the sealing rings comprise an anode side sealing ring arranged on the periphery of the fuel gas flow channel, a cathode side sealing ring arranged on the periphery of the reaction air flow channel, and cooling side sealing rings arranged at the inlet and the outlet of the air cooling plate;

and after the anode plate and the air cooling plate are connected together, the anode plate and the air cooling plate are stacked together to form the metal bipolar plate.

Preferably, the fuel gas flow passage and the reaction gas flow passage are linear, zigzag, or serpentine.

Preferably, the cooling gas flow channel is a plurality of parallel linear flow channels.

Preferably, the fuel gas inlet and the fuel gas outlet are arranged in a central symmetry, and the reaction air inlet and the reaction air outlet are arranged in a central symmetry.

Preferably, the reactant gas inlet is larger than the fuel gas inlet, and the reactant gas outlet is larger than the fuel gas outlet.

Preferably, the inlet and outlet of the anode and cathode plates are provided with corrugated gaskets.

Preferably, a pair of tabs are respectively arranged on two long sides of the anode plate and the cathode plate, the two tabs on the same pole plate are arranged in a centrosymmetric manner, and the tabs on the same side on different pole plates are arranged in the same position.

The invention also provides a cathode closed air-cooled pile which comprises an upper end plate, an upper current collecting plate, an electrode, a lower current collecting plate and a lower end plate which are sequentially arranged from top to bottom, wherein the metal bipolar plate of the electrode and the MEA membrane electrode are formed by staggered stacking.

Preferably, carbon paper is included between the upper and lower current collecting plates and the electrodes for reducing contact resistance.

Preferably, the reaction air and the cooling air are delivered by different air sources.

The invention has the beneficial effects that:

the air blower is adopted to provide reaction air for the galvanic pile, and the fan is adopted to force convection to supply air for the galvanic pile for air cooling, so that the reaction air and the cooling air are separated, a certain heat dissipation effect is ensured, meanwhile, the humidity in the battery is well maintained, and the durability of the galvanic pile is improved; the hydrogen inlet and the reaction air inlet are respectively positioned at two ends of the end plate, so that the crossing of hydrogen and reaction air is realized, and the hydrogen is humidified; the fan is positioned at the gas outlet side of the electric pile, so that the temperature of the outlet of the electric pile is relatively high, and part of water is taken out, so that the water heat distribution in the fuel cell is improved, and the performance of the electric pile is improved.

In the technical scheme provided by the invention, the metal bipolar plate can reduce the volume and weight of the galvanic pile, save the manufacturing cost and have good application prospect.

Drawings

Fig. 1a is a schematic structural view of a metal bipolar plate (anode plate facing upward) according to the present invention.

Fig. 1b is a schematic structural view of a metal bipolar plate (cathode plate facing upwards) provided by the invention.

Fig. 2 is a partial structural view of the metallic bipolar plate shown in fig. 1.

Fig. 3 is a schematic structural diagram of the anode plate shown in fig. 1.

Fig. 4 is a schematic structural view of the air-cooling panel shown in fig. 1.

Fig. 5 is a schematic view of the construction of the cathode plate shown in fig. 1.

FIG. 6 is a schematic view of the welded assembly of the anode plate and the air cooling plate of FIG. 1.

Fig. 7 is an exploded schematic view of a cathode closed air-cooled electric stack structure provided by the invention.

In the figure: 1-anode plate, 2-cathode plate, 3-air cooling plate, 4-anode side sealing ring, 5-cathode side sealing ring, 6-cooling side sealing ring, 7-anode corrugated gasket, 8-cathode corrugated gasket, 9-fuel gas flow channel, 10-sealing bulge, 11-cooling air flow channel, 12-reaction air flow channel, 13-nut, 14-upper end plate, 15-upper flow collecting plate, 16-carbon paper, 17-metal bipolar plate, 18-hard frame MEA membrane electrode, 19-fastening screw, 20-lower flow collecting plate, 21-lower end plate, 100 a-hydrogen inlet, 100 b-hydrogen outlet, 101 a-reaction air inlet, 101 b-reaction air outlet, 102-single voltage collecting tab, 141 a-end plate hydrogen inlet, 141 b-end plate hydrogen outlet, 142 a-end plate reaction air inlet, 142 b-end plate reaction air outlet, 210-mounting fixed threaded hole.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1a, 1b and 2, a metal bipolar plate 17 for a fuel cell according to the present invention includes an anode plate 1, an air-cooling plate 3 and a cathode plate 2 arranged in sequence. An anode side seal ring 4 is provided around the fuel gas flow channel 9 of the anode plate 1, a cathode side seal ring 5 is provided around the reaction air flow channel 12 of the cathode plate 2, and cooling side seal rings 6 are provided at the inlet and outlet of the air cooling plate 3.

As shown in fig. 2-5, a fuel gas channel 9 is provided on a side of the anode plate 1 away from the air cooling plate 3, and the fuel gas is hydrogen; one side of the negative plate 2, which is far away from the air cooling plate 3, is provided with a reaction air flow channel 12, two sides of the air cooling plate 3 are provided with cooling air flow channels 11, and the reaction air flow channel 12 and the cooling air flow channels 11 are completely separated by the negative plate 2, so that the reaction air and the cooling air are separated, and the humidity in the battery is well maintained while a certain heat dissipation effect is ensured.

As shown in FIGS. 1a and 1b, the active area of the metal bipolar plate of the fuel cell in this embodiment is 140cm²The shape is a long strip, and the size in the width direction is 50-70mm in order to prevent the temperature difference of the electric pile along the width direction from being too large. Two ends of the metal bipolar plate 17 are respectively provided with a hydrogen inlet and

outlet

100a and 100b and a reaction air inlet and

outlet

101a and 101b which are used as channels for gas to enter the bipolar plate; since the supply flow rate of hydrogen is smaller than the supply flow rate of air when the battery is in operation, the sizes of the hydrogen inlet and

outlet

100a and 100b are smaller than the sizes of the reaction air inlet and

outlet

101a and 101 b.

In this embodiment, an anode corrugated gasket 7 and a cathode corrugated gasket 8 are respectively welded at gas inlet and outlet positions of an anode plate 1 and a cathode plate 2, as shown in fig. 1a and 1b, the anode corrugated gasket 7 and the cathode corrugated gasket 8 have the function of supporting a hard frame MEA membrane electrode 18, so as to prevent the MEA membrane electrode from collapsing under the extrusion of a sealing ring at a relative position during the assembly or long-term operation of a stack, so as to block the gas flow, and the corrugated gaskets also have a flow guiding function; the height of the corrugated gasket is smaller than that of the gas flow channel, the corrugation period is larger than or equal to that of the flow channel, and corrugated bulges can be aligned to the flow channel ridges or staggered from the flow channel ridges when being welded and placed.

The metal bipolar plate is respectively provided with 2 single-voltage collecting lugs 102 on two long sides of an anode plate 1 and a cathode plate 2, and is used for monitoring the running condition of a single battery; the two single-voltage collecting lugs 102 on the same polar plate are distributed in central symmetry, and the single-voltage collecting lugs 102 on the same side of different polar plates are in the same position so as to be suitable for different discharge type placement of the galvanic pile.

In this embodiment, the unipolar plates such as the anode plate 1, the cathode plate 2, the air cooling plate 3 and the like are formed by single or multiple stamping of a metal plate with a thickness of 0.05-0.1mm to form a flow channel, and the flow channel is formed into a final plate shape by punching or laser cutting. As shown in fig. 3 and 5, the surfaces of the anode plate 1 and the cathode plate 2, which are far away from the air cooling plate, are provided with multi-channel folded straight channels or multi-channel serpentine channels. The groove depth of the fuel gas flow passage 9 and the reaction air flow passage 12 is 0.2-1mm, the groove width of the flow passage is 0.6-1.5mm, the ridge width of the flow passage is 0.6-1.5mm, and the ridge-groove ratio is set to be 1 for reducing the contact resistance and the flow resistance; the ridges and grooves of the fuel gas flow channel 9 and the reaction air flow channel 12 have the same width, but the groove depth of the fuel gas flow channel 9 is shallower than that of the reaction air flow channel 12, so that the flow rate of hydrogen is improved, the content of liquid water below the ridge of the anode plate 1 is reduced, the flow resistance of reaction air can be reduced, and a proper blower can be selected conveniently. The air cooling plate 3 is provided with a plurality of parallel direct current channels along the width direction, the cross sections of the channels are periodically changed, the width of the ridges and the grooves is 1.5-2mm, and the height of the ridges is 1.5-2.5 mm. Sealing bulges 10 are arranged on the peripheries of the anode plate 1 and the cathode plate 2, and the height of each sealing bulge 10 is smaller than that of the flow channel ridge. The air cooling plate 3 is provided with a sealing bulge 10, the sealing bulge 10 at the gas inlet and outlet position is tightly close to the edge of the gas inlet and outlet to prevent the sealing ring from sliding and dislocating and sinking into the inlet and outlet, and the sealing bulge 10 close to the edge of the flow channel has larger width, as shown in figure 4, has the function of strengthening support and prevents the gas leakage caused by the fact that the sealing ring 4 at the anode side or the sealing ring 5 at the cathode side at the corresponding position is not pressed.

As shown in fig. 2 and fig. 6, the anode plate 1 and the air cooling plate 3 of the present invention are welded by laser to form a whole, the welding is line welding and sealing at the two ends of the plate, the middle flow field area is spot welding and fixing, and the plate thus formed can be used in a cathode open air-cooled pile, and the air flowing through the cooling air channel of the air cooling plate 3 is used as the reaction gas and the cooling gas. The cathode plate 2 is directly stacked on the air cooling plate 3, and the formed electrode plate can be used in a cathode closed type air cooling electric pile, so that the invention gives consideration to two modes of cathode closed type and cathode open type air cooling electric piles.

And a cooling side sealing ring 6 is stuck in a sealing groove formed by the sealing bulge of the air cooling plate 3, and the elastic modulus of the material elastic model of the cooling side sealing ring 6 is larger than that of the anode side sealing ring 4 and the cathode side sealing ring 5.

The metal bipolar plate can be made of stainless steel, aluminum alloy, titanium alloy and the like, and is coated with an anticorrosive coating, such as a gold coating, a carbon coating, a composite coating and the like, so that the electric conductivity and the corrosion resistance are improved; the surface coating can adopt single-sided coating or double-sided coating.

As shown in fig. 1a, fig. 1b, and fig. 6, the anode side seal ring 4, the cathode side seal ring 5, and the cooling side seal ring 6 may be integrally formed by using seal ring patches cut by a cutting die or produced by a mold or by injection molding, and may be made of silicon rubber, ethylene propylene diene monomer, nitrile rubber, chloroprene rubber, natural rubber, or the like.

The invention also provides a cathode closed air-cooled pile which is composed of a plurality of fuel cell metal bipolar plates, hard frame MEA (membrane electrode assembly) membrane electrodes 18, an upper end plate 14, a lower end plate 21, an upper current collecting plate 15 and a lower current collecting plate 20, as shown in figure 7. A plurality of fastening screws 19 are mounted between the upper end plate 14 and the lower end plate 21 through mounting holes and fastened through nuts 13.

The upper end plate 14 and the lower end plate 21 are made of insulating materials, and the insulating materials are made of epoxy resin, engineering plastics and the like. The corresponding positions of the two ends of the upper end plate 14 and the lower end plate 21 are provided with end plate hydrogen inlets and

outlets

141a and 141b and end plate reaction air inlets and

outlets

142a and 142b which are opposite to the fuel metal bipolar plate hydrogen inlets and

outlets

100a and 100b and the reaction air inlets and

outlets

101a and 101b, the end plate hydrogen inlets and

outlets

141a and 141b and the end plate reaction air inlets and

outlets

142a and 142b can be tube threaded holes or through holes, the through holes are rectangular holes, and the peripheries of the holes are provided with mounting threaded holes which can be externally connected with manifolds. The gas inlet and outlet of the upper end plate 14 or the lower end plate 21 can be used independently, the other opposite end plate is used as a blind plate, the gas inlet and outlet on the blind plate is blocked and is not used, and the gas is distributed in a U shape in the battery; the gas inlet and outlet of the upper end plate 14 or the lower end plate 21 may be used simultaneously, and the gas may be distributed in a Z-shape or an S-shape in the battery. The hydrogen inlet and the reaction air inlet are respectively positioned at two ends of the end plate to realize the intersection of hydrogen and reaction air and humidify the hydrogen. The side walls of the peripheries of the upper end plate 14 and the lower end plate 21 are provided with mounting and fixing threaded holes 210, the mounting and fixing threaded holes 210 are embedded with steel sleeves, and the mounting and fixing threaded holes 210 can be used as external positioning fixing holes during electric pile assembly and can also be used as electric pile fan cover mounting fixing holes.

The upper current collecting plate 15 and the lower current collecting plate 20 can be pure copper plates, carbon paper 16 is pasted on the front faces of the upper current collecting plate and the lower current collecting plate, contact resistance between the current collecting plates and the bipolar plates is reduced, and the carbon paper is located in the anode side sealing ring 4 or the cathode side sealing ring 5; the upper current collecting plate 15 and the lower current collecting plate 20 can adopt an electricity collecting discharge type through a single-output or multi-output electricity collecting lug on the side surface or a central threaded electricity collecting mother column.

The hard frame MEA membrane electrode 18 adopts glass fiber cloth as a frame material, so that the edge of the electrode has certain strength, and gas leakage caused by deformation in the assembling or using process is prevented; the glass fiber cloth and the MEA membrane electrode form a whole through hot melt adhesive, and the hot melt adhesive is heated to a certain temperature through a flat vulcanizing machine to bond the glass fiber plate and the MEA membrane electrode together. The hard frame MEA membrane electrode 18, the anode plate 1 and the anode side sealing ring 4 form an anode hydrogen reaction area; the hard frame MEA membrane electrode 18, the cathode plate 2 and the cathode side sealing ring 5 form a cathode air reaction area.

The invention adopts the plurality of metal bipolar plates and the plurality of hard frame MEA18 to assemble the cathode closed air-cooling electric pile; the air blower is connected with the end plate reaction air inlet and

outlet

142a and 142b to provide reaction air for the galvanic pile, and the fan is adopted to force convection to supply air for the galvanic pile for air cooling, so that the separation of the reaction air and the cooling air is realized, a certain heat dissipation effect is ensured, the humidity in the battery is well maintained, and the durability of the galvanic pile is improved; the hydrogen inlet and the reaction air inlet are respectively positioned at two ends of the end plate, so that the cross flow of hydrogen and reaction air is realized, and the hydrogen is humidified; the fan is positioned at the gas outlet side of the electric pile, so that the temperature of the outlet of the electric pile is relatively high, and part of water is taken out, so that the water heat distribution in the fuel cell is improved, and the performance of the electric pile is improved.

In conclusion, the invention discloses a metal bipolar plate of a fuel cell, which comprises an anode plate, a cathode plate and an air cooling plate, wherein the anode plate and the air cooling plate are welded into a whole and combined with the cathode plate to separate reaction air from cooling air, so that the humidity in the cell is well maintained while a certain heat dissipation effect is ensured, and the service life of the cell is prolonged. The welded whole of the anode plate and the air cooling plate can be used as a bipolar plate of the cathode open type air cooling galvanic pile, and has better compatibility. The invention also provides a cathode closed air-cooled electric pile comprising the metal bipolar plate and the hard frame MEA membrane electrode, hydrogen and reaction air are crossed to realize self-humidification, and the cathode closed air-cooled electric pile is combined with a cooling fan to improve the water heat distribution in a fuel cell and improve the electric pile performance. The cathode closed type air cooling electric pile has the characteristics of light weight and small volume, and has strong practicability and economy.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. a metal bipolar plate of a fuel cell, comprising an anode plate, an air cooling plate and a cathode plate arranged in sequence, also comprising a sealing ring for preventing gas leakage, it is characterized in that,

A fuel gas flow channel is arranged on the side of the anode plate away from the air cooling plate, and the fuel gas flow channel is arranged along the length direction of the metal bipolar plate;

The side of the cathode plate away from the air cooling plate is provided with a reaction air flow channel, and the reaction air flow channel is arranged along the length direction of the metal bipolar plate;

Two sides of the air cooling plate are respectively provided with cooling air flow channels, and the cooling air flow channels are arranged along the width direction of the metal bipolar plate;

One end of the metal bipolar plate is provided with an inlet, including a fuel gas inlet and a reaction air inlet; the other end is provided with an outlet, including a fuel gas outlet and a reaction air outlet;

The sealing ring includes an anode side sealing ring arranged around the fuel gas flow channel, a cathode side sealing ring arranged around the reaction air flow channel, and a cooling side sealing ring arranged at the inlet and outlet of the air cooling plate. sealing ring;

After the anode plate and the air cooling plate are connected together, they are stacked with the cathode plate to form the metal bipolar plate.

2 . The metal bipolar plate according to claim 1 , wherein the fuel gas flow channel and the reaction gas flow channel are linear, zigzag or serpentine. 3 .

3 . The metal bipolar plate of claim 1 , wherein the cooling gas flow channel is a plurality of parallel linear flow channels. 4 .

4 . The metal bipolar plate of claim 1 , wherein the fuel gas inlet and the fuel gas outlet are centrally arranged symmetrically, and the reaction air inlet and the reaction air outlet are arranged centrally symmetrically. 5 .

5 . The metal bipolar plate of claim 1 , wherein the reaction gas inlet is larger than the fuel gas inlet, and the reaction gas outlet is larger than the fuel gas outlet. 6 .

6 . The metal bipolar plate according to claim 1 , wherein the inlet and the outlet of the anode plate and the cathode plate are provided with corrugated gaskets. 7 .

7. The metal bipolar plate according to claim 1, wherein a pair of pole lugs are respectively provided on the two long sides of the anode plate and the cathode plate, and the two pole lugs located on the same pole plate are centrally symmetric Set, the same side tabs on different plates are in the same position.

8. A cathode closed-type air-cooled stack, characterized in that it comprises an upper end plate, an upper current collecting plate, an electrode, a lower current collecting plate and a lower end plate placed in sequence from top to bottom, and the electrode is composed of the upper end plate as claimed in claim 1- 7. The metal bipolar plate described in any one of the items and the MEA membrane electrode are alternately stacked.

9 . The cathode closed air-cooled stack according to claim 8 , wherein carbon paper is included between the upper current collecting plate and the lower current collecting plate and the electrodes to reduce contact resistance. 10 .

10. The cathode closed air-cooled stack of claim 8, wherein the reaction air and the cooling air are delivered by different air sources.