A metal bipolar plate flow field system for a proton exchange membrane fuel cell

Abstract

A proton exchange membrane fuel cell metal bipolar plate flow field system belongs to the field of fuel cell technology. The bipolar plate is connected by an anode monopolar plate, a cathode monopolar plate and a middle partition to form a three-layer structure, which respectively forms a fuel flow field, an oxidant flow field, and a coolant flow field II and a coolant flow field I. The above-mentioned proton exchange membrane fuel cell metal bipolar plate flow field system has the advantages of small pressure drop of multi-channel serpentine flow channels and good gas diffusion of interdigital flow channels in the anode flow field; the cathode flow field retains the advantages of convenient exhaust and low pressure drop of multi-channel serpentine flow channels, and the convex hull makes the oxidant flowing in the flow channel diffuse to the diffusion layer to increase the battery power; the dual coolant flow fields with two groups of coolant flowing in opposite directions make the coolant cooling temperature more uniform, and the consistency of the working area of ​​the fuel cell is better, which greatly improves the thermal control ability of the fuel cell and provides a guarantee for the safety of the fuel cell.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells, and in particular to a metal bipolar plate flow field system for a proton exchange membrane fuel cell. Technical Background

[0002] At present, the battery industry, such as lithium batteries, lead-acid batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, have great hidden dangers in environmental protection and safety. With the development of science and technology, it is difficult to meet the requirements of green energy. It is urgent to develop new alternative products. Fuel cells are a power generation device that converts the chemical energy in fuel and oxygen into electrical energy directly through electrochemical reactions under isothermal conditions without combustion. It is considered to be the ultimate solution to the energy and environmental crisis.

[0003] Proton membrane fuel cells have become an ideal alternative to automobile power sources and energy storage power stations due to their excellent low temperature and environmental protection properties. Metal bipolar plates have become one of the important material applications for bipolar plates, the main component of proton membrane fuel cells, due to their unique excellent performance.

[0004] Currently, the proton membrane fuel cell bipolar plates on the market are mainly graphite bipolar plates, and the application of metal bipolar plates is still in the initial stage. Issues such as how to increase battery output power, improve drainage performance to prevent flooding, and improve system thermal management efficiency, thereby improving safety and stability, have put forward requirements for the flow field design of fuel cell metal bipolar plates. Summary of the invention

[0005] In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to design and provide a technical solution for a proton exchange membrane fuel cell metal bipolar plate flow field system, which significantly improves the battery output power. The dual coolant flow fields with two groups of coolant flow directions in opposite directions make the coolant cooling temperature more uniform and the consistency of the fuel cell working area better, which greatly improves the thermal control capability of the fuel cell and provides a guarantee for the safety of the fuel cell.

[0006] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that the bipolar plate is composed of an anode monopolar plate, a cathode monopolar plate and a middle partition, which form a fuel flow field, an oxidant flow field, and a coolant flow field II and a coolant flow field I respectively.

[0007] The metal bipolar plate flow field system for a proton exchange membrane fuel cell is characterized in that the front side of the anode monopolar plate is a fuel flow field, and a full-flow multi-channel serpentine-interdigitated flow channel or a multi-channel serpentine flow channel is adopted; at the same time, the full-flow flow channel forms a complete multi-channel serpentine coolant flow channel on the back side, which is a coolant flow field II.

[0008] The metal bipolar plate flow field system for a proton exchange membrane fuel cell is characterized in that the front side of the cathode monopolar plate is an oxidant flow field, with a multi-channel serpentine flow channel with a convex hull in the middle, and the first and last two channels are ordinary smooth serpentine flow channels; at the same time, a complete multi-channel serpentine coolant flow channel is formed on the back side, which is the coolant flow field I.

[0009] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that the middle partition is a flat plate with holes, and the two sides of the middle partition are respectively connected to the cathode monopolar plate and the anode monopolar plate, and coolant flow field I and coolant flow field II are formed on both sides of the middle partition; the flow channels of coolant flow field I and coolant flow field II are arranged in opposite directions.

[0010] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that an anode plate fuel air inlet channel, an anode plate coolant inlet channel, an anode plate oxidant air inlet channel, an anode plate oxidant air outlet channel, an anode plate coolant outlet channel, an anode plate fuel outlet channel, an anode plate fuel inlet channel small hole, and an anode plate fuel outlet channel small hole are arranged on the anode monopolar plate body; an anode plate fuel flow channel is arranged on the front side of the anode monopolar plate, and a section of an anode plate fuel flow field transition channel is arranged at the beginning and end of the anode plate fuel flow channel, and an anode plate sealing position is arranged on the outer plate body of the anode plate fuel flow channel; a coolant flow field II coolant flow channel, an anode plate fuel air inlet cavity, an anode plate coolant inlet cavity, and an anode plate fuel outlet cavity are arranged on the back side of the anode monopolar plate, and an anode plate welding / bonding position is arranged on the outer periphery of the coolant flow field II coolant flow channel, and the anode plate fuel air inlet cavity and the anode plate fuel outlet cavity are respectively connected to the anode plate fuel flow field transition channel through the anode plate fuel inlet channel small hole and the anode plate fuel outlet channel small hole.

[0011] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that a cathode plate oxidant air inlet channel, a cathode plate coolant inlet channel, a cathode plate fuel air inlet channel, a cathode plate fuel air outlet channel, a cathode plate coolant outlet channel, a cathode plate oxidant air outlet channel, a cathode plate oxidant air inlet channel small hole, and a cathode plate oxidant air outlet channel small hole are arranged on the plate body of the cathode monopolar plate; a cathode plate oxidant flow channel is arranged on the front side of the cathode monopolar plate, a section of cathode plate oxidant flow field transition channel is arranged at the beginning and end of the cathode plate oxidant flow channel, and a cathode plate sealing position is arranged on the periphery of the cathode plate oxidant flow channel; a coolant flow field I coolant flow channel, a cathode plate oxidant air inlet cavity, a coolant outlet cavity, and a cathode plate oxidant air cavity are arranged on the back side of the cathode monopolar plate, a cathode plate welding / bonding position is arranged on the periphery of the coolant flow field I coolant flow channel, and the cathode plate oxidant air inlet cavity, the cathode plate oxidant air cavity and the cathode plate oxidant flow field transition channel are connected through the cathode plate oxidant inlet channel small hole and the cathode plate oxidant outlet channel small hole respectively.

[0012] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that an oxidant air inlet channel, a coolant inlet channel, a fuel air inlet channel, a coolant flow field I inlet channel rectangular hole, a coolant inlet channel I, a coolant inlet channel II, and a coolant flow field II inlet channel rectangular hole are arranged on the coolant flow field inlet end plate of the middle partition, and a fuel air outlet channel, a coolant outlet channel, an oxidant air outlet channel, a coolant flow field II outlet channel rectangular hole, a coolant outlet channel II, a coolant outlet channel I, and a coolant flow field I outlet channel rectangular hole are arranged on the coolant flow field outlet end plate of the middle partition.

[0013] The metal bipolar plate flow field system for a proton exchange membrane fuel cell is characterized in that the thickness of the anode monopolar plate, the cathode monopolar plate and the intermediate partition are all 0.05-0.5 mm, preferably 0.08-0.12 mm.

[0014] The metal bipolar plate flow field system of a proton exchange membrane fuel cell is characterized in that the anode plate fuel flow channel and the cathode plate oxidant flow channel have a flow channel depth of 0.1-2.5 mm, a flow channel width of 0.5-2.5 mm, and a ridge width of 0.5-2.5 mm.

[0015] The above-mentioned proton exchange membrane fuel cell metal bipolar plate flow field system includes a three-layer structure of a cathode monopolar plate, an anode monopolar plate and an intermediate partition. Its anode fuel flow field is a full-process multi-channel serpentine-interdigital flow channel or a multi-channel serpentine flow channel, the cathode oxidant flow field is a multi-channel serpentine flow channel with a convex hull, and the intermediate coolant flow field is composed of two layers of dual coolant flow fields with opposite coolant flows. Its anode flow field retains the advantages of low pressure drop of multi-channel serpentine flow channels and good gas diffusion of interdigital flow channels; the cathode flow field retains the advantages of convenient exhaust and low pressure drop of multi-channel serpentine flow channels, and the convex hull makes the oxidant flowing in the flow channel facilitate diffusion to the diffusion layer to increase the battery power; the dual coolant flow field with two groups of coolant flows in opposite directions makes the coolant cooling temperature more uniform, and the consistency of the fuel cell working area is better, which greatly improves the thermal control ability of the fuel cell and provides a guarantee for the safety of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the split structure of the bipolar plate of the present invention;

[0017] Figure 2 It is a schematic diagram of the front structure of the anode plate surface of the bipolar plate of the present invention;

[0018] Figure 3 Schematic diagram of the side structure of the bipolar plate of the present invention;

[0019] Figure 4 It is a schematic diagram of the front structure of the cathode plate surface of the bipolar plate of the present invention;

[0020] Figure 5 It is a schematic diagram of the structure of the middle partition of the present invention;

[0021] Figure 6 It is a schematic diagram of the reverse structure of the anode monopolar plate of the present invention;

[0022] Figure 7 for Figure 6 AA cross-sectional structural diagram;

[0023] Figure 8 It is a schematic diagram of the front structure of the anode monopolar plate of the present invention;

[0024] Fig. 9 for Figure 7 Schematic diagram of the local structure of B;

[0025] Fig.10 Schematic diagram of the cross-sectional structure of the cathode monopolar plate of the present invention;

[0026] Fig.11 It is a schematic diagram of the reverse structure of the cathode monopolar plate of the present invention;

[0027] Fig.12 FIG. 1 is a schematic diagram of the partial structure of the cathode monopolar plate of the present invention;

[0028] In the figure: 1-anode monopolar plate, 2-cathode monopolar plate, 3-middle partition, S1-anode plate fuel inlet channel, S2-anode plate coolant inlet channel, S3-anode plate oxidant inlet channel, S4-anode plate oxidant outlet channel, S5-anode plate coolant outlet channel, S6-anode plate fuel outlet channel, S7-anode plate sealing position, S8-anode plate fuel flow channel, S9-anode plate fuel flow field transition channel, S10-anode plate fuel outlet channel small hole, S1 1-anode plate fuel inlet channel small hole, S12-anode plate welding / bonding position, S13-coolant flow field II coolant flow channel, S14-anode plate fuel inlet cavity, S15-anode plate coolant inlet cavity, S16-anode plate fuel outlet cavity; H1-cathode plate oxidant inlet channel, H2-cathode plate coolant inlet channel, H3-cathode plate fuel inlet channel, H4-cathode plate fuel outlet channel, H5-cathode plate coolant outlet channel, H6-cathode plate oxidant outlet Air channel, H7-cathode plate sealing position, H8-cathode plate oxidant flow channel, H9-cathode plate oxidant flow field transition channel, H10-cathode plate oxidant outlet channel small hole, H11-cathode plate oxidant inlet channel small hole, H12-cathode plate welding / bonding position, H13-coolant flow field I coolant flow channel, H14-cathode plate oxidant air inlet cavity, H15-coolant outlet cavity, H16-cathode plate oxidant air cavity; K1-oxidant air inlet channel, K2-coolant inlet Channel, K3-fuel inlet channel, K4-fuel outlet channel, K5-coolant outlet channel, K6-oxidant outlet channel, K7-coolant flow field I inlet channel rectangular hole, K8-coolant inlet channel I, K9-coolant inlet channel II, K10-coolant flow field II inlet channel rectangular hole, K11-coolant flow field II outlet channel rectangular hole, K12-coolant outlet channel II, K13-coolant outlet channel I, K14-coolant flow field I outlet channel rectangular hole. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] As shown in the figure, the proton exchange membrane fuel cell metal bipolar plate flow field system, the bipolar plate is formed by laser welding or gluing an anode monopolar plate 1, a cathode monopolar plate 2 and a middle partition plate 3, which respectively form a fuel flow field, an oxidant flow field and a coolant flow field II and a coolant flow field I.

[0031] Furthermore, the front side of the anode monopolar plate 1 is a fuel flow field, which adopts a full-process multi-channel serpentine-interdigitated flow channel or a multi-channel serpentine flow channel; at the same time, the full-process flow channel forms a complete multi-channel serpentine coolant flow channel on the back side, which is a coolant flow field II.

[0032] Furthermore, the front side of the cathode monopolar plate 2 is an oxidant flow field, which adopts a multi-channel serpentine flow channel with a convex hull in the middle, and the first and last two are ordinary smooth serpentine flow channels; at the same time, a complete multi-channel serpentine coolant flow channel is formed on the back side, which is the coolant flow field I.

[0033] Furthermore, the middle partition 3 is a flat plate with holes, and the two sides of the middle partition 3 are respectively connected to the cathode monopolar plate 2 and the anode monopolar plate 1, and the two sides of the middle partition 3 form a coolant flow field I and a coolant flow field II respectively; the flow channels of the coolant flow field I and the coolant flow field II are arranged in opposite directions.

[0034] Furthermore, the anode plate monopolar plate 1 is provided with an anode plate fuel inlet channel S1, an anode plate coolant inlet channel S2, an anode plate oxidant inlet channel S3, an anode plate oxidant outlet channel S4, an anode plate coolant outlet channel S5, an anode plate fuel outlet channel S6, an anode plate fuel inlet channel small hole S11, and an anode plate fuel outlet channel small hole S10; an anode plate fuel flow channel S8 is provided on the front side of the anode monopolar plate 1, and a section of an anode plate fuel flow field transition channel S9 is provided at the beginning and end of the anode plate fuel flow channel S8, and the anode plate fuel flow channel S 8 The outer plate body is provided with an anode plate sealing position S7; the back side of the anode monopolar plate 1 is provided with a coolant flow field II coolant flow channel S13, an anode plate fuel air inlet cavity S14, an anode plate coolant liquid inlet cavity S15, and an anode plate fuel outlet cavity S16; the outer side of the coolant flow field II coolant flow channel S13 is provided with an anode plate welding / bonding position S12; the anode plate fuel air inlet cavity S14 and the anode plate fuel outlet cavity S16 are respectively connected to the anode plate fuel flow field transition channel S9 through the anode plate fuel inlet channel small hole S11 and the anode plate fuel outlet channel small hole S10. One side of the anode monopolar plate is a fuel flow field. If a full-process multi-channel serpentine-interdigital flow channel is adopted, the advantages of small pressure drop of the multi-channel serpentine flow channel and good gas diffusion of the interdigital flow channel are retained, and at the same time, the full-process flow channel forms a complete multi-channel serpentine coolant flow channel on the other side. A section of anode plate fuel flow field transition channel S9 is set at the beginning and end of the anode plate full-process multi-channel serpentine-interdigital flow channel or multi-channel serpentine flow channel. The anode plate inlet and outlet air cavity S14 is connected to the anode plate fuel flow field transition channel S9 through the anode plate fuel inlet channel small hole S11 or the anode plate fuel outlet channel small hole S10. There are sealing grooves around all the inlet and outlet air and inlet and outlet cooling liquid cavities, and the reverse side of the sealing groove is a laser welding / bonding surface to form an anode plate welding / bonding line S12. This structure not only ensures that the fuel flow field fuel does not leak out, but also blocks the infiltration of the back cooling liquid flow field fuel.

[0035] Furthermore, the cathode plate oxidant inlet channel H1, the cathode plate coolant inlet channel H2, the cathode plate fuel inlet channel H3, the cathode plate fuel outlet channel H4, the cathode plate coolant outlet channel H5, the cathode plate oxidant outlet channel H6, the cathode plate oxidant inlet channel small hole H11, and the cathode plate oxidant outlet channel small hole H10 are arranged on the plate body of the cathode monopolar plate 2; the cathode plate oxidant flow channel H8 is arranged on the front side of the cathode monopolar plate 2, and a cathode plate oxidant flow field transition channel H9 is arranged at the beginning and end of the cathode plate oxidant flow channel H8, and the cathode plate oxidant flow field transition channel H9 is arranged at the beginning and end of the cathode plate oxidant flow channel H8. A cathode plate sealing position H7 is arranged around the cathode monopolar plate 2; a coolant flow field I coolant flow channel H13, a cathode plate oxidant air inlet cavity H14, a coolant outlet cavity H15, and a cathode plate oxidant air cavity H16 are arranged on the reverse side of the cathode monopolar plate 2; a cathode plate welding / bonding position H12 is arranged around the coolant flow field I coolant flow channel H13; the cathode plate oxidant air inlet cavity H14, the cathode plate oxidant air cavity H16 and the cathode plate oxidant flow field transition channel H9 are connected through the cathode plate oxidant inlet channel small hole H11 and the cathode plate oxidant outlet channel small hole H10 respectively. One side of the cathode monopolar plate 2 is an oxidant flow field. In order to facilitate drainage and improve the output power of the fuel cell at the same time, a multi-channel serpentine flow channel with a convex hull is adopted. This flow channel retains the multi-channel serpentine flow channel exhaust convenience pressure drop, and the convex hull makes the oxidant flowing in the flow channel facilitate diffusion to the diffusion layer, and at the same time forms a complete multi-channel serpentine coolant flow channel on the other side. Similarly, a cathode plate oxidant flow field transition channel H9 is also provided at the beginning and end of the multi-channel serpentine flow channel with a convex hull, and the cathode plate inlet and outlet air cavity H14 is connected to the cathode plate oxidant flow field transition channel H9 through the cathode plate oxidant inlet channel small hole H11 or the cathode plate oxidant outlet channel small hole H10. There are sealing grooves around all the inlet and outlet air and inlet and outlet cooling liquid cavities, and the reverse side of the sealing groove is a laser welding / bonding surface. This structure not only ensures that the oxidant in the oxidant flow field does not leak out, but also blocks the infiltration of the oxidant in the back cooling liquid flow field.

[0036] Furthermore, the upper plate of the coolant flow field of the middle partition 3 is provided with an oxidant inlet channel K1, a coolant inlet channel K2, a fuel inlet channel K3, a coolant flow field I inlet channel rectangular hole K7, a coolant inlet channel I K8, a coolant inlet channel II K9, and a coolant flow field II inlet channel rectangular hole K10, and the lower plate of the coolant flow field of the middle partition 3 is provided with a fuel outlet channel K4, a coolant outlet channel K5, an oxidant outlet channel K6, a coolant flow field II outlet channel rectangular hole K11, a coolant outlet channel II K12, a coolant outlet channel I K13, and a coolant flow field I outlet channel rectangular hole K14. The corresponding positions of the middle partition 3 have fuel, oxidant and coolant inlet and outlet channels, and at the same time, the relative positions of the start and end of the flow channels of the cathode monopolar plate and the anode monopolar plate and the appropriate positions outside the coolant sealing groove have coolant circulation and inlet and outlet channel rectangular holes. The two sides of the middle partition are connected to the cathode monopolar plate 2 and the anode monopolar plate 1 respectively. A layer of coolant flow field is formed on each side of the middle partition. The flow channels of the two coolant flow fields are arranged in opposite directions. The beginning and end of the flow channel are the rectangular holes of the inlet and outlet channels of the middle partition 3. The coolant enters the flow channel through the rectangular holes of the inlet and outlet channels from the other side of the middle partition, and flows out from the other side of the middle partition 3 through the rectangular holes of the inlet and outlet channels on the middle partition 3 after passing through the flow field. Since the coolant flow field is composed of two groups of flow fields with opposite coolant flow directions, the coolant cooling temperature is more uniform, the consistency of the fuel cell working area is better, and the thermal control ability of the fuel cell is greatly improved. Excellent thermal control ability is the basis for the stable operation of the fuel cell and provides a guarantee for the safety of the fuel cell.

[0037] Furthermore, the thickness of the raw material plates of the anode monopolar plate 1, the cathode monopolar plate 2, and the intermediate partition plate 3 is 0.05-0.5 mm, preferably 0.08-0.12 mm. In order to improve the specific power and price advantage of the fuel cell, the thickness of the raw material plate of the present invention is preferably the above-defined parameters when the strength and formability are appropriate.

[0038] Furthermore, the channel depth of the anode plate fuel channel S8 and the cathode plate oxidant channel H8 is 0.1-2.5 mm, the channel width is 0.5-2.5 mm, and the ridge width is 0.5-2.5 mm.

[0039] The working process of the present invention is as follows:

[0040] Cooling liquid flow field I: The cooling liquid enters the anode plate coolant inlet cavity S15 on the anode plate side from the cooling liquid inlet channel K2, passes through the cooling liquid inlet channel IK8 of the middle partition and enters the cavity in front of the flow channel on the cathode plate side. At this time, the cooling liquid is divided into two parts, wherein the first part of the cooling liquid passes through the middle partition from the cooling liquid inlet channel IIK9 back to the cavity in front of the flow channel on the anode side, and then passes through the middle partition from the cooling liquid flow field I inlet channel rectangular hole K7 to enter the cathode side cooling liquid flow field I. After passing through the cooling liquid flow field I, it flows out of the flow field from the outlet end of the cooling liquid flow field I through the cooling liquid flow field I outlet channel rectangular hole K14 of the middle partition to the cavity behind the flow channel on the cathode side, and after merging with the other part of the cooling liquid, it passes through the cooling liquid outlet channel IK13 on the middle partition and flows back to the cathode side, enters the cathode plate cooling liquid outlet cavity H15, and then flows out of the bipolar plate from the cooling liquid outlet channel K5.

[0041] Coolant flow field II: The coolant enters the anode plate coolant inlet cavity S15 on the anode plate side from the coolant inlet channel K2, passes through the coolant inlet channel IK8 of the middle partition and enters the cavity in front of the flow channel on the cathode plate side. At this time, the coolant is divided into two parts, of which the second part of the coolant passes through the middle partition from the coolant flow field II inlet channel rectangular hole K10 to enter the coolant flow field II on the anode side. After passing through the coolant flow field II, it passes through the coolant flow field II outlet channel rectangular hole K11 of the middle partition from the outlet end of the coolant flow field II to the cavity behind the flow channel of the cathode, passes through the coolant outlet channel IIK12 of the middle partition and flows back to the anode plate side. After merging with the other part of the coolant, it passes through the coolant outlet channel IK13 on the middle partition and flows back to the cathode side, enters the cathode plate coolant outlet cavity H15, and then flows out of the bipolar plate from the coolant outlet channel K5.

[0042] Fuel flow field: The fuel enters the fuel inlet cavity S14 on the anode side from the fuel inlet channel S1, enters the fuel flow field transition channel S9 through the anode plate fuel inlet channel hole S11, enters the fuel flow field flow channel S8, and the fuel flows out of the flow field into the fuel flow field transition channel S9 and the fuel outlet channel hole S10 to reach the fuel outlet cavity S16, and then is discharged from the fuel outlet channel S6.

[0043] Oxidant flow field: The oxidant enters the oxidant inlet cavity H14 on the cathode side from the oxidant inlet channel H1, enters the oxidant flow field transition channel H9 through the cathode plate oxidant inlet channel hole H11, enters the oxidant flow field flow channel H8, and the oxidant flows out of the flow field into the oxidant flow field transition channel H9 and the oxidant outlet channel hole H10 to reach the oxidant outlet cavity H16, and then is discharged from the oxidant outlet channel H6.

[0044] The above technical solutions describe the present invention in detail, but are not intended to limit the scope of the present invention. It should be understood that any obvious changes or substitutions of the present invention by those skilled in the art based on the teachings of the present invention should also be considered as the protection scope of the present invention.

Claims

1. A proton exchange membrane fuel cell metal bipolar plate flow field system, characterized in that The bipolar plate is composed of an anode monopolar plate (1), a cathode monopolar plate (2) and a middle partition plate (3) connected to form a fuel flow field, an oxidant flow field, and a coolant flow field II and a coolant flow field I respectively; The front side of the anode monopolar plate (1) is a fuel flow field, which adopts a full-flow multi-channel serpentine-interdigitated flow channel; at the same time, the full-flow flow channel forms a complete multi-channel serpentine coolant flow channel on the back side, which is a coolant flow field II; The front side of the cathode monopolar plate (2) is an oxidant flow field, which adopts a multi-channel serpentine flow channel with a convex hull in the middle, and the first and last two channels are ordinary smooth serpentine flow channels; at the same time, a complete multi-channel serpentine coolant flow channel is formed on the back side, which is a coolant flow field I; The middle partition (3) is a flat plate with holes. The two sides of the middle partition (3) are connected to the cathode monopolar plate (2) and the anode monopolar plate (1) respectively. The two sides of the middle partition (3) form a coolant flow field I and a coolant flow field II respectively. The flow channels of the coolant flow field I and the coolant flow field II are arranged in opposite directions. A section of anode plate fuel flow field transition channel (S9) is provided at the beginning and end of the anode plate full-process multi-channel serpentine-interdigitated flow channel, and the anode plate fuel air inlet cavity (S14) is connected to the anode plate fuel flow field transition channel (S9) through the anode plate fuel inlet channel small hole (S11) or the anode plate fuel outlet channel small hole (S10); all air inlet and outlet, inlet and outlet cooling liquid cavities are surrounded by sealing grooves, and the reverse side of the sealing groove is a laser welding / bonding surface to form an anode plate welding / bonding position (S12); A cathode plate oxidant flow field transition channel (H9) is also provided at the beginning and end of the cathode plate multi-channel serpentine flow channel with a convex hull. The cathode plate inlet and outlet air cavity (H14) is connected to the cathode plate oxidant flow field transition channel (H9) through the cathode plate oxidant inlet channel small hole (H11) or the cathode plate oxidant outlet channel small hole (H10). There are sealing grooves around all the inlet and outlet air and inlet and outlet cooling liquid cavities, and the reverse side of the sealing groove is a laser welding / bonding position (H12). An oxidant air inlet channel (K1), a coolant inlet channel (K2), a fuel air inlet channel (K3), a coolant flow field I inlet channel rectangular hole (K7), a coolant inlet channel I (K8), a coolant inlet channel II (K9), and a coolant flow field II inlet channel rectangular hole (K10) are arranged on the coolant flow field inlet end plate body of the middle partition (3), and a fuel air outlet channel (K4), a coolant outlet channel (K5), an oxidant air outlet channel (K6), a coolant flow field II outlet channel rectangular hole (K11), a coolant outlet channel II (K12), a coolant outlet channel I (K13), and a coolant flow field I outlet channel rectangular hole (K14) are arranged on the coolant flow field outlet end plate body of the middle partition (3).

2. A proton exchange membrane fuel cell metal bipolar plate flow field system as claimed in claim 1, characterized in that The anode monopolar plate (1) is provided with an anode plate fuel inlet channel (S1), an anode plate coolant inlet channel (S2), an anode plate oxidant inlet channel (S3), an anode plate oxidant outlet channel (S4), an anode plate coolant outlet channel (S5), an anode plate fuel outlet channel (S6), an anode plate fuel inlet channel small hole (S11), and an anode plate fuel outlet channel small hole (S10); an anode plate fuel flow channel (S8) is provided on the front side of the anode monopolar plate (1), and a section of an anode plate fuel flow field transition channel (S9) is provided at the beginning and end of the anode plate fuel flow channel (S8). The anode plate fuel flow channel (S8) An anode plate sealing position (S7) is provided on the outer plate body; a coolant flow field II coolant flow channel (S13), an anode plate fuel air inlet cavity (S14), an anode plate coolant liquid inlet cavity (S15), and an anode plate fuel air outlet cavity (S16) are provided on the back side of the anode monopolar plate (1); an anode plate welding / bonding position (S12) is provided on the outer periphery of the coolant flow field II coolant flow channel (S13); the anode plate fuel air inlet cavity (S14) and the anode plate fuel air outlet cavity (S16) are respectively connected to the anode plate fuel flow field transition channel (S9) through the anode plate fuel inlet channel small hole (S11) and the anode plate fuel outlet channel small hole (S10).

3. A proton exchange membrane fuel cell metal bipolar plate flow field system as claimed in claim 1, characterized in that The cathode plate oxidant inlet channel (H1), the cathode plate coolant inlet channel (H2), the cathode plate fuel inlet channel (H3), the cathode plate fuel outlet channel (H4), the cathode plate coolant outlet channel (H5), the cathode plate oxidant outlet channel (H6), the cathode plate oxidant inlet channel small hole (H11), and the cathode plate oxidant outlet channel small hole (H10) are arranged on the plate body of the cathode unipolar plate (2); the cathode plate oxidant flow channel (H8) is arranged on the front side of the cathode unipolar plate (2); a cathode plate oxidant flow field transition channel (H9) is arranged at the beginning and end of the cathode plate oxidant flow channel (H8); and the cathode plate oxidant flow channel (H8) is provided with a plurality of cathode plate oxidant flow field transition channels (H9). A cathode plate sealing position (H7) is arranged on the periphery of the cathode plate (H8); a coolant flow field I coolant flow channel (H13), a cathode plate oxidant air inlet cavity (H14), a coolant outlet cavity (H15), and a cathode plate oxidant air cavity (H16) are arranged on the reverse side of the cathode monopolar plate (2); a cathode plate welding / bonding position (H12) is arranged on the periphery of the coolant flow field I coolant flow channel (H13); the cathode plate oxidant air inlet cavity (H14), the cathode plate oxidant air cavity (H16) and the cathode plate oxidant flow field transition channel (H9) are connected through the cathode plate oxidant inlet channel small hole (H11) and the cathode plate oxidant outlet channel small hole (H10), respectively.

4. A proton exchange membrane fuel cell metal bipolar plate flow field system as claimed in claim 2 or 3, characterized in that The thickness of the anode monopolar plate (1), the cathode monopolar plate (2), and the intermediate partition plate (3) are all 0.05-0.5 mm.

5. A proton exchange membrane fuel cell metal bipolar plate flow field system as claimed in claim 2 or 3, characterized in that The channel depth of the anode plate fuel channel (S8) and the cathode plate oxidant channel (H8) is 0.1-2.5 mm, the channel width is 0.5-2.5 mm, and the ridge width is 0.5-2.5 mm.

6. A proton exchange membrane fuel cell metal bipolar plate flow field system as claimed in claim 4, characterized in that The thickness of the anode monopolar plate (1), the cathode monopolar plate (2), and the intermediate partition plate (3) are all 0.08-0.12 mm.

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