CN212783523U

CN212783523U - Bipolar plate and fuel cell

Info

Publication number: CN212783523U
Application number: CN202021687725.XU
Authority: CN
Inventors: 张磊; 张威; 肖彪; 刘智亮
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2021-03-23
Anticipated expiration: 2030-08-13

Abstract

The present application provides a bipolar plate and a fuel cell. The bipolar plate comprises a cathode plate (1) and an anode plate (2), wherein the cathode plate (1) and the anode plate (2) are unipolar plates with the same structure, the cathode plate (1) comprises a first oxygen interface (3), a second oxygen interface (4), a first hydrogen interface (5), a second hydrogen interface (6), a first cooling liquid interface (7) and a second cooling liquid interface (8), the first cooling liquid interface (7) is symmetrical about a longitudinal middle plane of the cathode plate (1), the second cooling liquid interface (8) is centrosymmetric with the first cooling liquid interface (7), the first hydrogen interface (5) and the first oxygen interface (3) are symmetrical about a transverse middle plane of the cathode plate (1), and the second hydrogen interface (6) and the second oxygen interface (4) are symmetrical about a transverse middle plane of the cathode plate (1). According to the bipolar plate, the die opening cost can be reduced, the die replacement time during stamping is shortened, and the production efficiency of the bipolar plate is improved.

Description

Bipolar plate and fuel cell

Technical Field

The application relates to the technical field of fuel cells, in particular to a bipolar plate and a fuel cell.

Background

The fuel cell stack (hereinafter referred to as stack) mainly comprises the following components: end plates, bipolar plates (also called separators), membrane electrodes (comprising a carbon paper diffusion layer, an electrolyte membrane and a catalytic layer).

The main reactants (hydrogen and oxygen) are bipolar plates which are divided into a cathode plate (oxygen side) and an anode plate (hydrogen side), and the materials are divided into a metal plate, a graphite plate and a composite plate. Metal bipolar plates are the main direction of development because of their high strength, light weight and good electrical conductivity.

There are several applications for the design of bipolar plates at home and abroad. The most common forming method of the metal bipolar plate is stamping of an ultrathin metal plate, the stamping has the advantage of batch production, and the bipolar plate has good batch quality consistency.

However, in the actual production process, because the anode plate and the cathode plate have different structures, two sets of dies are required to form the anode plate and the cathode plate respectively, so that the die opening cost is increased, the die replacement time during stamping is shortened, and the production efficiency of the electrode plate is reduced.

SUMMERY OF THE UTILITY MODEL

Therefore, the present application provides a bipolar plate and a fuel cell, which can reduce the cost of die opening, shorten the time for die replacement during stamping, and improve the production efficiency of the bipolar plate.

In order to solve the above problems, the present application provides a bipolar plate including a cathode plate and an anode plate, the cathode plate and the anode plate being unipolar plates having the same structure, the cathode plate including a first oxygen port, a second oxygen port, a first hydrogen port, a second hydrogen port, a first coolant port, and a second coolant port, the first coolant port being symmetrical with respect to a longitudinal mid-plane of the cathode plate, the second coolant port being centrosymmetric with respect to the first coolant port, the first hydrogen port and the first oxygen port being symmetrical with respect to a transverse mid-plane of the cathode plate, and the second hydrogen port and the second oxygen port being symmetrical with respect to the transverse mid-plane of the cathode plate.

Preferably, the first hydrogen interface and the second oxygen interface are symmetrical with respect to the longitudinal mid-plane of the cathode plate.

Preferably, the cathode plate is provided with an oxygen flow channel, and the oxygen flow channel is symmetrical about the center of the cathode plate.

Preferably, the first end of the oxygen flow channel is communicated with the first oxygen interface, the second end of the oxygen flow channel is communicated with the second oxygen interface, and the oxygen flow channel is in a zigzag shape.

Preferably, the cathode plate comprises a reaction side and a cooling side, the reaction side is provided with a plurality of flow guide bulges, and an oxygen flow channel is formed between every two adjacent flow guide bulges.

Preferably, the plurality of flow guide protrusions include a first flow guide protrusion and a second flow guide protrusion, the first flow guide protrusion includes a first fold line segment, a second fold line segment and a third fold line segment, the second flow guide protrusion includes a first partition segment and a second partition segment, the first fold line segment is communicated with the first oxygen interface, the first partition segment is located between two adjacent second fold line segments, the oxygen flow channel between two adjacent second fold line segments is divided into two, the second partition segment is located between two adjacent third fold line segments, and the oxygen flow channel between two adjacent third fold line segments is divided into two.

Preferably, the plurality of flow guide protrusions further include a third flow guide protrusion, which is disposed between the third broken line segment and the second partition segment and divides the oxygen flow passage between the third broken line segment and the second partition segment into two.

Preferably, the oxygen flow passages between adjacent first fold sections, the oxygen flow passages between the first and second partition sections, and the oxygen flow passages between the third and second partition sections are the same in width.

Preferably, the width of the oxygen flow channel is the same as the width of the first guide protrusion, the second guide protrusion and the third guide protrusion.

Preferably, the end boundary of the first broken line segment forms an angle α with the end boundary of the first separating segment, where α ═ arccos 1/3.

Preferably, the first broken line segment, the third broken line segment, the second separation segment and the third diversion protrusion are parallel to each other, and the second broken line segment and the first separation segment are parallel to each other.

Preferably, on the reaction side of the cathode plate, sealing glue grooves are arranged on the peripheral sides of the first hydrogen interface, the second hydrogen interface, the first oxygen interface, the second oxygen interface, the first cooling liquid interface and the second cooling liquid interface.

Preferably, the oxygen flow channels between the second fold segments of the cooling side of the cathode plate are cross-fitted with the oxygen flow channels between the second fold segments of the cooling side of the anode plate.

According to another aspect of the present application, there is provided a fuel cell including a bipolar plate, which is the bipolar plate described above.

The bipolar plate comprises a cathode plate and an anode plate, wherein the cathode plate and the anode plate are unipolar plates with the same structure, the cathode plate comprises a first hydrogen interface, a second hydrogen interface, a first oxygen interface, a second oxygen interface, a first cooling liquid interface and a second cooling liquid interface, the first cooling liquid interface is symmetrical about a longitudinal middle plane of the cathode plate, the second cooling liquid interface is centrosymmetric with the first cooling liquid interface, the first hydrogen interface and the first oxygen interface are symmetrical about a transverse middle plane of the cathode plate, and the second hydrogen interface and the second oxygen interface are symmetrical about the transverse middle plane of the cathode plate. The first cooling liquid interface of the bipolar plate is symmetrical about the longitudinal middle plane of the cathode plate, the second cooling liquid interface is centrosymmetric with the first cooling liquid interface, the first hydrogen interface and the first oxygen interface are symmetrical about the transverse middle plane of the cathode plate, and the second hydrogen interface and the second oxygen interface are symmetrical about the transverse middle plane of the cathode plate, so that a special matching relation is formed between the structures of each gas interface and the cooling interface, thereby ensuring that when the same set of mold is used for molding the anode plate and the cathode plate with the same structure, the molded unipolar plate can be used as the anode plate and the cathode plate, and each interface of the anode plate and the cathode plate can realize good matching, thereby smoothly realizing a one-mold double-plate structure, saving one set of mold, reducing the mold manufacturing cost and shortening the mold replacement time during stamping, and the production efficiency of the polar plate is improved.

Drawings

FIG. 1 is a view showing the structure of a cathode plate of a bipolar plate according to an embodiment of the present invention;

fig. 2 is an exploded structural view of a bipolar plate according to an embodiment of the present application;

FIG. 3 is a partial cross-sectional structural view of a bipolar plate according to an embodiment of the present application;

FIG. 4 is a schematic view of a coolant flow channel structure of a bipolar plate according to an embodiment of the present application;

fig. 5 is a structural view of a cathode plate of a bipolar plate according to another embodiment of the present application.

The reference numerals are represented as:

1. a cathode plate; 2. an anode plate; 3. a first oxygen interface; 4. a second oxygen interface; 5. a first hydrogen interface; 6. a second hydrogen interface; 7. a first coolant port; 8. a second coolant port; 9. an oxygen flow channel; 10. a first broken line segment; 11. a second fold line segment; 12. a third broken line segment; 13. a first separation section; 14. a second divided section; 15. a third flow guide bulge; 16. sealing the glue groove; 17. a flow distribution protrusion; 18. and a cooling liquid flow passage.

Detailed Description

Referring to fig. 1 to 5 in combination, according to an embodiment of the present application, the bipolar plate includes a cathode plate 1 and an anode plate 2, the cathode plate 1 and the anode plate 2 are unipolar plates having the same structure, the cathode plate 1 includes a first oxygen port 3, a second oxygen port 4, a first hydrogen port 5, a second hydrogen port 6, a first coolant port 7, and a second coolant port 8, the first coolant port 7 is symmetrical with respect to a longitudinal mid-plane of the cathode plate 1, the second coolant port 8 is centrosymmetrical with respect to the first coolant port 7, the first hydrogen port 5 and the first oxygen port 3 are symmetrical with respect to a transverse mid-plane of the cathode plate 1, and the second hydrogen port 6 and the second oxygen port 4 are symmetrical with respect to the transverse mid-plane of the cathode plate 1.

The first cooling liquid interface 7 of the bipolar plate is symmetrical about the longitudinal middle plane of the cathode plate 1, the second cooling liquid interface 8 is centrosymmetric with the first cooling liquid interface 7, the first hydrogen interface 5 and the first oxygen interface 3 are symmetrical about the transverse middle plane of the cathode plate 1, and the second hydrogen interface 6 and the second oxygen interface 4 are symmetrical about the transverse middle plane of the cathode plate 1, so that a special matching relation is formed between the structures of each gas interface and the cooling interface, thereby ensuring that when the anode plate 2 and the cathode plate 1 with the same mould forming structure are adopted, the formed single-pole plate can be used as the anode plate 2 and the cathode plate 1, and the interfaces of the anode plate 2 and the cathode plate 1 can be well matched, thereby smoothly realizing a one-mould double-plate structure, saving one set of mould and reducing the mould manufacturing cost, the time for replacing the die during stamping is shortened, and the production efficiency of the polar plate is improved.

Referring to fig. 1 in combination, the longitudinal median plane is a plane passing through the center of the short side of the cathode plate 1 and perpendicular to the plate surface of the cathode plate 1, and the transverse median plane is a plane passing through the center of the long side of the cathode plate 1 and perpendicular to the plate surface of the cathode plate 1.

Each unipolar plate of the bipolar plate in the application adopts a die and double-plate design, and the reaction side of the order polar plate of the fuel cell punched by the die can be used as an anode plate 2 for hydrogen reaction and can also be used as a cathode plate 1 for oxygen reaction. The two unipolar plates form a bipolar plate with two plates and three fields in a laser welding or gluing mode, the two plates and the three fields refer to that the reaction sides of the two polar plates are respectively used as reaction fields for respective reaction of oxygen and hydrogen, and a cavity formed by the measured cooling sides of the two polar plates is a cooling field for flowing of cooling water.

When carrying out bipolar plate's preparation, can regard as negative plate 1 one in the unipolar board that one set of mould was made, later earlier with the second unipolar board adopt with negative plate 1 the same structure of placing, rotate 180 around unipolar board center with the second unipolar board again, as anode plate 2, then to this second unipolar board around long limit upset 180, carry out the superpose equipment to two unipolar boards at last, make the cooling side laminating of two unipolar boards together, and fix together through sticky or welded mode, form bipolar plate.

The bipolar plate has the structural characteristics of one die and two plates, can save the die manufacturing cost of actual production and the die replacement time cost during stamping production outside the same fuel cell reaction function, and is suitable for mass production of the fuel cell bipolar plates.

The first hydrogen interface 5 and the second oxygen interface 4 are symmetrical about the longitudinal middle plane of the cathode plate 1, so that the four gas interface structures are consistent in shape, the consistency of the shapes of the gas interfaces can be improved, and the forming efficiency is improved.

The oxygen runner 9 is arranged on the negative plate 1, the oxygen runner 9 is symmetrical about the center of the negative plate 1, so that the design of a mold is facilitated, the design cost of the mold is reduced, and the design of the oxygen runner 9 and a cooling side runner is facilitated.

The first end of the oxygen flow channel 9 is communicated with the first oxygen interface 3, the second end of the oxygen flow channel 9 is communicated with the second oxygen interface 4, and the oxygen flow channel 9 is in a zigzag shape. In this embodiment, first oxygen interface 3, first hydrogen interface 5 and first coolant liquid interface 7 are located the first end on the long limit of negative plate 1, and for setting up side by side, second oxygen interface 4, second hydrogen interface 6 and second coolant liquid interface 8 are located the second end on the long limit of negative plate 1, and for setting up side by side, oxygen runner 9 is zigzag-shaped and sets up, be favorable to realizing first oxygen interface 3, second oxygen interface 4 and oxygen runner 9's being connected and overall arrangement more.

The cathode plate 1 comprises a reaction side and a cooling side, the reaction side is provided with a plurality of flow guide bulges, and an oxygen flow channel 9 is formed between every two adjacent flow guide bulges.

In one embodiment, the plurality of flow guide protrusions include a first flow guide protrusion and a second flow guide protrusion, the first flow guide protrusion includes a first fold line segment 10, a second fold line segment 11 and a third fold line segment 12, the second flow guide protrusion includes a first partition segment 13 and a second partition segment 14, the first fold line segment 10 is communicated with the first oxygen interface 3, the first partition segment 13 is located between two adjacent second fold line segments 11 to divide the oxygen flow channel 9 between the two adjacent second fold line segments 11 into two, the second partition segment 14 is located between two adjacent third fold line segments 12 to divide the oxygen flow channel 9 between the two adjacent third fold line segments 12 into two, so that the number of the oxygen flow channels 9 is gradually increased along the direction from the edge to the middle, the oxygen is in full contact reaction with the hydrogen in the central area, and the reaction efficiency of the gas is improved.

In one embodiment, the plurality of flow guide protrusions further includes a third flow guide protrusion 15, and the third flow guide protrusion 15 is disposed between the third folding line segment 12 and the second separation segment 14 and divides the oxygen flow channel 9 between the third folding line segment 12 and the second separation segment 14 into two.

The utility model provides a runner structure, utilize the characteristics of the runner width widen that the bending becomes in runner kink department, protruding through increasing new water conservancy diversion, realize separating once more to the runner after buckling, thereby can conveniently increase runner quantity, use first oxygen interface 3 as the initiating terminal, from first broken line section 10 to the in-process of second broken line section 11, the quantity of single oxygen runner 9 is divided into 2 runners from 1 runner, from the in-process of second broken line section 11 to third broken line section 12, the single runner is divided into 2 runners again, make oxygen runner 9 in the in-process from first broken line section 10 to third broken line section 12, the direct current way region from 1 runner of initiating terminal to middle zone divides into 4 runners, with this save the area that polar plate air inlet or gas outlet arranged, make the polar plate structure compacter.

In one embodiment, the unipolar plate is a metal plate, and the metal unipolar plate with the above-mentioned flow channel structure may be formed by pressing the metal plate with a thickness of 0.1mm by stamping. Wherein the unipolar plate is provided with an oxygen inlet and outlet, a hydrogen inlet and outlet and a cooling water inlet and outlet. Wherein the oxygen inlet and outlet and the hydrogen inlet and outlet are respectively arranged at two sides of the cooling water inlet and outlet, and the periphery of the unipolar plate is provided with 4 positioning holes. The unipolar plates may also be graphite plates.

On the side of the anode plate 2, hydrogen flows into the flow field area of the anode plate 2 through the hydrogen inlet on the anode plate 2, then diffuses to the straight flow channel part of the middle area of the whole anode plate 2 through the flow channel, and the reacted hydrogen tail gas is converged to the hydrogen outlet again through the hydrogen flow channel to flow out.

In one embodiment, the widths of the oxygen flow channel 9 between the adjacent first folding line segments 10, the oxygen flow channel 9 between the first separating segment 13 and the second folding line segment 11, and the oxygen flow channel 9 between the third folding line segment 12 and the second separating segment 14 are the same, so that the width of a single flow channel can be kept unchanged basically during the splitting process of the gas flow channel, and therefore, the sudden change in the gas flow flowing process can be reduced, and the uniformity and the stability of the gas flow can be improved.

The width of the oxygen channel 9 is the same as the width of the first flow guide protrusion, the second flow guide protrusion and the third flow guide protrusion 15.

The end boundary of the first fold line segment 10 forms an angle α with the end boundary of the first separating segment 13, where α is arccos1/3, the second fold line segment 11 and the first separating segment 13 are perpendicular to the end boundary of the first fold line segment 10, and the third fold line segment 12, the second separating segment 14 and the third guide projection 15 are perpendicular to the end boundary of the first separating segment 13.

As for the width of the oxygen flow channel 9 is the same as the width of the first flow guiding protrusion, the second flow guiding protrusion and the third flow guiding protrusion 15, and the width of each flow channel is the same as the width of the protrusion, therefore, the width of the oxygen flow channel 9 can be increased from L in the region where the first broken line 10 is located to 3L in the region where the second broken line 11 is located by setting the included angle α between the terminal boundary of the first broken line 10 and the terminal boundary of the first partition section 13, because the first partition section 13 with the width L is added in the middle of the oxygen flow channel 9 in the region where the second broken line 11 is located, the remaining 2L of the oxygen flow channel 9 can be divided into two by the first partition section 13, so that the width of the oxygen flow channel 9 between the first partition section 13 and the second broken line 11 is also L, thereby the width of a single oxygen flow channel 9 is constant as L, the flow stability of the fluid in the flow channel is improved.

In the present embodiment, the first fold line segment 10, the third fold line segment 12, the second partition segment 14 and the third guide protrusion 15 are parallel to each other, and the second fold line segment 11 and the first partition segment 13 are parallel to each other. The first fold line segment 10 and the third fold line segment 12 are both parallel to the longitudinal middle plane of the unipolar plate, so that the fluid flow channels of the areas where the first fold line segment 10 and the third fold line segment 12 are both straight flow channels, and the flow is smoother.

On the reaction side of the cathode plate 1, the first hydrogen interface 5, the second hydrogen interface 6, the first oxygen interface 3, the second oxygen interface 4, the first cooling liquid interface 7 and the second cooling liquid interface 8 are all provided with a sealant groove 16, and a sealant ring is arranged in the sealant groove 16 to seal and isolate the gas interface and the cooling liquid interface. The cooling liquid cavity is sealed by gluing or laser welding to form the bipolar plate by the two unipolar plates, and only the cooling water inlet and the cooling water outlet are left; seal gas inlet and coolant flow cavity, prevent that gas and coolant from revealing. And sealing the assembled bipolar plate by the sealing rubber ring to seal the gas.

The oxygen flow channels 9 between the second fold segments 11 on the cooling side of the cathode plate 1 are in cross fit with the oxygen flow channels 9 between the second fold segments 11 on the cooling side of the anode plate 2.

The cooling side of the unipolar plate in this embodiment is provided with a cooling liquid channel 18, and the cooling liquid channel 18 is recessed on the cooling side of the unipolar plate to form a flow guide protrusion on the reaction side of the unipolar plate.

The cooling liquid forms a cooling liquid circulation port similar to a bridge opening structure through the sealing rubber grooves of the cathode plate and the anode plate and the flow distribution bulge 17 supporting the sealing rubber grooves, the cooling liquid flows into the staggered flow field area of the cathode plate and the anode plate through the bridge opening structures on the left side and then flows into a cavity formed by two polar plates in the straight flow channel area, heat dissipation of chemical reaction heat is carried out, and the cooling liquid after heat dissipation flows out of the bipolar plate through the staggered area on the right side.

The flow dividing protrusion 17 in this embodiment is disposed between the first coolant connection 7 and the coolant flow channel 18, and between the second coolant connection 8 and the coolant flow channel 18, for dividing the coolant and supporting the bipolar plate.

The minimum distance between the edge of the flow dividing protrusion 17 between the first cooling liquid interface 7 and the cooling liquid flow channel 18 and the edge of the first cooling liquid interface 7 is L1, the minimum distance between the edge of the flow dividing protrusion 17 between the second cooling liquid interface 8 and the cooling liquid flow channel 18 and the edge of the second cooling liquid interface 8 close to the cooling liquid flow channel 18 is L2, wherein L1 is greater than L2, so that after the bipolar plate is formed by two unipolar plates, the flow dividing protrusion 17 on the cathode plate 1 can be staggered with the flow dividing protrusion 17 on the anode plate 2, and the bipolar plate can play both effective supporting and flow guiding roles.

In one embodiment, the first oxygen port 3 is an oxygen inlet, the second oxygen port 4 is an oxygen outlet, the first hydrogen port 5 is a hydrogen inlet, the second hydrogen port 6 is a hydrogen outlet, the first coolant port 7 is a coolant inlet, and the second coolant port 8 is a coolant outlet.

In one embodiment, the oxygen inlet is a special-shaped structure, particularly, the rectangular interface is trimmed at the corner positions of the outer edge to form a trimming structure, the trimming structure can reduce the area of the rectangular interface, and positioning holes located at four corners are arranged to be closer to the edge of the bipolar plate, so that the peripheral size of the bipolar plate is smaller, and the reduction of the overall volume and the area of the bipolar plate is facilitated.

In another embodiment, the oxygen inlet is of a rectangular structure, so that the structure of the oxygen inlet is regular, only one direction of mechanical movement needs to be controlled during welding, welding laser light is stable in light emitting, shaking is not easy to generate, and therefore welding yield can be improved.

The structures of the hydrogen inlet and the hydrogen outlet are similar and will not be described in detail here.

According to an embodiment of the present application, a fuel cell includes a bipolar plate, which is the bipolar plate described above.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed. The foregoing is only a preferred embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present application, and these modifications and variations should also be considered as the protection scope of the present application.

Claims

1. A bipolar plate is characterized by comprising a cathode plate (1) and an anode plate (2), the cathode plate (1) and the anode plate (2) are unipolar plates with the same structure, the cathode plate (1) comprises a first oxygen interface (3), a second oxygen interface (4), a first hydrogen interface (5), a second hydrogen interface (6), a first cooling liquid interface (7) and a second cooling liquid interface (8), the first coolant connection (7) is symmetrical with respect to the longitudinal mid-plane of the cathode plate (1), the second cooling liquid port (8) is centrosymmetric with the first cooling liquid port (7), the first hydrogen port (5) and the first oxygen port (3) are symmetrical with respect to the transverse mid-plane of the cathode plate (1), the second hydrogen interface (6) and the second oxygen interface (4) are symmetrical with respect to the transverse mid-plane of the cathode plate (1); and on the reaction side of the cathode plate (1), sealing rubber grooves (16) are formed in the peripheral sides of the first hydrogen interface (5), the second hydrogen interface (6), the first oxygen interface (3), the second oxygen interface (4), the first cooling liquid interface (7) and the second cooling liquid interface (8).

2. A bipolar plate according to claim 1, characterised in that the first hydrogen interface (5) and the second oxygen interface (4) are symmetrical with respect to the longitudinal mid-plane of the cathode plate (1).

3. A bipolar plate according to claim 1, characterised in that oxygen flow channels (9) are provided in the cathode plate (1), the oxygen flow channels (9) being symmetrical with respect to the centre of the cathode plate (1).

4. A bipolar plate according to claim 3, wherein a first end of the oxygen flow channel (9) communicates with the first oxygen port (3), a second end of the oxygen flow channel (9) communicates with the second oxygen port (4), and the oxygen flow channel (9) has a zigzag shape.

5. A bipolar plate according to claim 4, characterised in that the cathode plate (1) comprises a reaction side and a cooling side, the reaction side being provided with a plurality of flow-guiding bulges, the oxygen flow channels (9) being formed between adjacent flow-guiding bulges.

6. The bipolar plate of claim 5, wherein the plurality of flow-directing protrusions comprise first flow-directing protrusions and second flow-directing protrusions, the first flow guide bulge comprises a first broken line segment (10), a second broken line segment (11) and a third broken line segment (12), the second flow guide bulge comprises a first separation section (13) and a second separation section (14), the first fold line segment (10) is communicated with the first oxygen interface (3), the first separation segment (13) is positioned between two adjacent second fold line segments (11) to separate the oxygen flow channel (9) between the two adjacent second fold line segments (11) into two, the second separation section (14) is positioned between two adjacent third broken line sections (12) and divides the oxygen flow channel (9) between the two adjacent third broken line sections (12) into two parts.

7. A bipolar plate as claimed in claim 6, wherein the plurality of flow-guiding projections further comprises a third flow-guiding projection (15), the third flow-guiding projection (15) being arranged between the third fold line segment (12) and the second separator segment (14) and dividing the oxygen flow channel (9) between the third fold line segment (12) and the second separator segment (14) into two.

8. A bipolar plate as claimed in claim 7, wherein the oxygen gas flow channels (9) between adjacent first fold sections (10), the oxygen gas flow channels (9) between the first and second partition sections (13, 11) and the oxygen gas flow channels (9) between the third fold sections (12, 14) are of the same width.

9. A bipolar plate as claimed in claim 8, wherein the width of the oxygen flow channels (9) is the same as the width of the first, second and third flow-guiding projections (15).

10. A bipolar plate according to claim 9, wherein the end boundary of the first folding line segment (10) and the end boundary of the first separator segment (13) form an angle α, wherein α = arccos 1/3.

11. A bipolar plate as claimed in claim 10, wherein the first fold line segment (10), the third fold line segment (12), the second separator segment (14) and the third guide projection (15) are parallel to each other, and the second fold line segment (11) and the first separator segment (13) are parallel to each other.

12. A bipolar plate according to claim 6, characterised in that the oxygen flow channels (9) between the second fold sections (11) of the cooling side of the cathode plate (1) cross-fit with the oxygen flow channels (9) between the second fold sections (11) of the cooling side of the anode plate (2).

13. A fuel cell comprising a bipolar plate, said bipolar plate being the bipolar plate of any one of claims 1 to 12.