Bipolar plates for fuel cells

Abstract

The present invention discloses a bipolar plate for a fuel cell, which comprises a first metal plate and a second metal plate, both ends of which are provided with openings for a fuel channel, an opening for an oxidant channel and an opening for a coolant channel; the first metal plate and the second metal plate are arranged opposite to each other; sealing bosses are arranged around the opposite openings at both ends of the first metal plate and the second metal plate; a hollow cavity is formed between the openings at both ends of the first metal plate and the second metal plate and between the oppositely arranged sealing bosses, and a sealing interlayer is further arranged in the hollow cavity; along the port cross-section of the first metal plate, the sealing interlayer is wavy; the present invention increases the support of the sealing boss, improves the rigidity of the sealing boss, and prevents plastic deformation from occurring at the sealing boss by arranging a wavy sealing interlayer in the hollow cavity formed by the oppositely arranged sealing bosses of the first metal plate and the second metal plate.

Description

Technical Field

[0001] The invention relates to a bipolar plate of a fuel cell. Background Art

[0002] A fuel cell is a power generation system that converts chemical energy directly into electrical energy in a fuel cell stack using an electrochemical method, rather than converting the chemical energy of the fuel into heat through combustion. Fuel cells can be applied not only to industry, home appliances, and vehicles, but also to the power supply of small-scale electrical and electronic devices such as portable devices.

[0003] The main core components of fuel cells are membrane electrode and bipolar plate, where the membrane electrode is mainly composed of catalyst layer, diffusion layer, proton exchange membrane, etc., and the bipolar plate is composed of cathode plate and anode plate.

[0004] Sealing components are an important part of fuel cells, and their performance directly affects the power generation efficiency and life of the fuel cell.

[0005] Patents US20180226665A1, US20190097248A1 and CN113285086A all adopt the sealing boss solution to solve the problem of gas sealing and the entry of reaction gas into the plate reaction area. However, the issue of the bearing capacity of the sealing boss is not addressed.

[0006] Under the action of the stack assembly force, the sealing boss is deformed by force. Once the yield strength of the metal material is exceeded, plastic deformation will occur at the sealing boss and the pre-tightening force on the sealing material will relax, thereby increasing the risk of sealing failure. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the problem of possible plastic deformation of the sealing boss in the prior art, and to provide a bipolar plate for a fuel cell, which improves the rigidity of the sealing boss, prevents plastic deformation at the sealing boss, reduces the risk of sealing failure, has a simple structure, and is easy to implement.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The present invention provides a bipolar plate for a fuel cell, comprising a first metal plate and a second metal plate, both ends of the first metal plate and the second metal plate are provided with an opening of a fuel channel, an opening of an oxidant channel and an opening of a coolant channel; the first metal plate and the second metal plate are arranged opposite to each other; sealing bosses are provided around the opposite openings at both ends of the first metal plate and the second metal plate;

[0010] A hollow cavity is formed between the openings at both ends of the first metal plate and the second metal plate and between the oppositely arranged sealing bosses, and a sealing interlayer is also provided in the hollow cavity; along the port section of the first metal plate, the sealing interlayer is wavy.

[0011] In the technical solution, a wavy sealing interlayer is provided in the hollow cavity to enhance the rigidity of the sealing boss, prevent plastic deformation of the sealing boss, and reduce the risk of sealing failure.

[0012] Preferably, the surface of the first metal plate that is not in contact with the second metal plate is an outer surface, and a concave-convex groove is provided in the middle of the outer surface of the first metal plate, and the concave-convex groove is a gas flow channel.

[0013] In the present technical solution, the outer surface of the first metal plate is a reaction surface for providing fuel, oxidant and gas for chemical reaction.

[0014] Preferably, the openings at both ends of the gas flow channel are connected to the oxidant channel and the fuel channel respectively.

[0015] Preferably, the sealing boss is also provided around the side edges of the first metal plate and the second metal plate.

[0016] In the present technical solution, the sealing boss arranged around the side edges of the first metal plate and the second metal plate will also surround the sealing boss and the gas flow channel arranged between the relative openings at both ends of the first metal plate and the second metal plate. By setting a plurality of sealing bosses, the sealing between the bipolar plates of the fuel cell can be further enhanced.

[0017] Preferably, the oxidant channels of the first metal plate and the second metal plate include oxidant feed channels.

[0018] Preferably, a plurality of first ridges are arranged side by side at both ends of the first metal plate, the first ridges are arranged near the end surface of the first metal plate and intersect with the sealing boss of the first metal plate; a plurality of second ridges are arranged side by side on the second metal plate and are opposite to the first ridges; the second ridges intersect with the sealing boss of the second metal plate; the first ridges and the second ridges form the oxidant feeding channel;

[0019] and / or, the height of the first protrusion does not exceed the height of the sealing boss of the first metal plate and the height of the second protrusion does not exceed the height of the sealing boss of the second metal plate;

[0020] And / or, the width of the oxidant feed channel is 0.5 mm-2 mm;

[0021] And / or, the intervals between the oxidant feed channels are 1 mm to 2.5 mm.

[0022] In the present technical solution, the oxidant enters the oxidant feed channel from the opening of the oxidant channel.

[0023] Preferably, the surface where the first metal plate and the second metal plate are in contact is the inner surface; the first protrusion terminates after intersecting with the sealing boss of the first metal plate; the second protrusion continues to extend toward the other end of the second metal plate after intersecting with the sealing boss of the second metal plate to form an extension portion; the extension portion does not exceed the central axis between the two end surfaces of the second metal plate; the extension portion and the inner surface of the first metal plate form a second cavity.

[0024] In the present technical solution, the oxidant feed channel, the wavy sealing interlayer and the second cavity are connected, and after the oxidant flows through the oxidant feed channel, it passes through the wavy sealing interlayer and enters the second cavity.

[0025] Preferably, the first metal plate is provided with at least one through hole, and the edge of the through hole does not exceed the projection of the termination point of the extension portion of the second protrusion on the first metal plate;

[0026] The oxidant feed channel, the wavy sealing interlayer, the second cavity and the through hole are connected to form the oxidant channel.

[0027] In the technical solution, the shape of the through hole is preferably circular, and the hole edge of the circular through hole is tangent to the projection of the end of the extension of the second protrusion on the first metal plate. The oxidant enters from the oxidant feed channel, passes through the wavy sealing interlayer, and then enters the second cavity, and finally flows out of the through hole to the outer surface of the first metal plate to participate in the chemical reaction; the hole edge of the through hole is tangent to the projection of the end of the extension of the second protrusion on the first metal plate, so that the oxidant will not accumulate inside the second cavity, and the circular through hole facilitates the outflow of the oxidant.

[0028] Preferably, the first metal plate and the second metal plate are connected by welding;

[0029] The welded welding line surrounds the sealing boss of the first metal plate and the sealing boss of the second metal plate; and the second protrusion stops at a first preset distance from the welding line.

[0030] In the present technical solution, preferably the through hole is a circular through hole, and the distance between the welding wire and the center of the through hole is the sum of the first distance and the radius of the through hole. This setting can ensure the sealing of the first metal plate and the second metal plate.

[0031] The welding lines are used to separate the fuel channel, the oxidant channel and the coolant channel into regions that are not interconnected.

[0032] In the present technical solution, the fuel channel, the oxidant channel and the coolant channel are separated by the welding wires and their interiors are not interconnected, thereby preventing the fuel, oxidant and coolant from mixing with each other before the fuel and oxidant enter the reaction surface, thereby affecting the performance of the fuel cell.

[0033] Preferably, the first metal plate is a cathode metal plate, and the second metal plate is an anode metal plate.

[0034] In the present technical solution, the surface where the cathode metal plate is in contact with the anode metal plate is the inner surface, and the inner surface of the cathode metal plate is the cooling surface, which is used to pass the coolant for cooling; the surface where the cathode metal plate is not in contact with the anode metal plate is the outer surface, and the outer surface of the cathode metal plate is the reaction surface, and the oxidant, fuel and gas undergo a chemical reaction on the reaction surface of the cathode metal plate.

[0035] The positive progressive effect of the present invention is that: the present invention forms a hollow cavity by relatively arranged sealing bosses between the openings at both ends of the first metal plate and the second metal plate, and arranges a wavy sealing interlayer in the hollow cavity. On the basis of not hindering the circulation of fuel, oxidant and coolant, the support of the sealing boss is increased, the rigidity of the sealing boss is improved, plastic deformation is prevented at the sealing boss, the risk of sealing failure is reduced, the structure is simple, and implementation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the bipolar plate of Example 1 of the present invention.

[0037] Figure 2 for Figure 1 Schematic diagram of the structure at the AA cross section.

[0038] Figure 3 for Figure 1 A partial schematic diagram of point B in the middle.

[0039] Description of reference numerals: gas flow channel 1, fuel channel 2, oxidant channel 3, coolant channel 4, sealing boss 5, welding line 6, first ridge 7, second ridge 8, oxidant feed channel 9, sealing interlayer 10, second cavity 11, through hole 12, cathode metal plate 13, anode metal plate 14 DETAILED DESCRIPTION

[0040] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0041] Example 1

[0042] The structural schematic diagram of the bipolar plate provided in this embodiment is as follows Figure 1 As shown; the structural schematic diagram of the bipolar plate provided in this embodiment at the AA cross section is as shown Figure 2 As shown; the partial schematic diagram of the B portion of the bipolar plate provided in this embodiment is as shown Figure 3 shown.

[0043] The bipolar plate of the fuel cell provided in this embodiment comprises a first metal plate and a second metal plate, wherein the first metal plate is a cathode metal plate 13, and the second metal plate is an anode metal plate 14; both ends of the cathode metal plate 13 and the anode metal plate 14 are provided with an opening of a fuel channel 2, an opening of an oxidant channel 3, and an opening of a coolant channel 4; the cathode metal plate 13 and the anode metal plate 14 are arranged opposite to each other; and sealing bosses 5 are provided between the opposite openings at both ends of the cathode metal plate 13 and the anode metal plate 14;

[0044] A hollow cavity is formed between the opposite openings at both ends of the cathode metal plate 13 and the anode metal plate 14 and between the oppositely arranged sealing bosses 5, and a sealing interlayer 10 is also arranged in the hollow cavity; wherein the sealing interlayer 10 has a wavy cross section along the port of the cathode metal plate 13.

[0045] The wavy sealing interlayer 10 can enhance the rigidity of the sealing boss 5, prevent the sealing boss 5 from plastic deformation, and reduce the risk of sealing failure.

[0046] The surface where the cathode metal plate 13 and the anode metal plate 14 are connected is the inner surface, and the inner surface of the cathode metal plate 13 is the cooling surface, which is used to pass the coolant for cooling; the surface of the cathode metal plate 13 that is not connected to the anode metal plate 14 is the outer surface, that is, the reaction surface, and the oxidant, fuel and gas undergo chemical reactions on the reaction surface of the cathode metal plate 13.

[0047] A gas flow channel 1 formed by concave-convex grooves is provided in the middle of the outer surface of the cathode metal plate 13 .

[0048] The openings at both ends of the gas flow channel 1 are connected to the oxidant channel 3 and the fuel channel 2 respectively.

[0049] Preferably, a sealing boss 5 is also provided around the sides of the cathode metal plate 13 and the anode metal plate 14 .

[0050] In one possible implementation scheme, the sealing boss 5 arranged around the sides of the cathode metal plate 13 and the anode metal plate 14 will also surround the sealing boss 5 and the gas flow channel 1 arranged between the oxidant channel 3, the fuel channel 2, the coolant channel 4. By arranging multiple sealing bosses 5, the sealing between the bipolar plates of the fuel cell can be further enhanced.

[0051] In one possible implementation, the oxidant channel 3 includes an oxidant feed channel 9. A plurality of first ridges 7 are arranged side by side at both ends of the cathode metal plate 13, the first ridges 7 are arranged near the end surface of the cathode metal plate 13 and intersect with the sealing boss 5 of the cathode metal plate 13; a plurality of second ridges 8 are arranged side by side on the anode metal plate 14 and are opposite to the first ridges 7; the second ridges 8 intersect with the sealing boss 5 of the anode metal plate 14; the first ridges 7 and the second ridges 8 form an oxidant feed channel 9; the oxidant enters the oxidant feed channel 9 from the opening of the oxidant channel 3;

[0052] The height of the first protrusion 7 does not exceed the height of the sealing boss 5 of the cathode metal plate 13 and the height of the second protrusion 8 does not exceed the height of the sealing boss 5 of the anode metal plate 14;

[0053] Preferably, the width of the oxidant feed channel 9 is 0.5 mm-2 mm;

[0054] Preferably, the intervals between the oxidant feeding channels 9 are 1 mm to 2.5 mm.

[0055] In an implementable scheme, the first protrusion 7 terminates after intersecting with the sealing boss 5 of the cathode metal plate 13; the second protrusion 8 continues to extend toward the other end of the anode metal plate 14 after intersecting with the sealing boss 5 of the anode metal plate 14 to form an extension portion; the extension portion does not exceed the central axis between the two end surfaces of the anode metal plate 14; the extension portion and the inner surface of the cathode metal plate 13 form a second cavity 11.

[0056] In one possible implementation, the cathode metal plate 13 is provided with at least one through hole 12, and the edge of the through hole 12 does not exceed the projection of the end of the extension of the second ridge 8 on the cathode metal plate 13;

[0057] The oxidant feed channel 9 , the corrugated sealing interlayer 10 , the second cavity 11 and the through hole 12 are connected to form the oxidant channel 3 .

[0058] Preferably, the through hole 12 is circular, and the hole edge of the circular through hole 12 is tangent to the projection of the cathode metal plate 13 at the end of the extension of the second protrusion 8. The oxidant enters from the oxidant feed channel 9, passes through the wavy sealing interlayer 10, and then enters the second cavity 11, and finally flows out from the through hole 12 to the outer surface of the cathode metal plate 13 to participate in the chemical reaction;

[0059] like Figure 2As shown, the hole edge of the through hole 12 is tangent to the projection of the end of the extension of the second protrusion 8 on the cathode metal plate 13 so as not to cause the oxidant to accumulate inside the second cavity 11, and the circular through hole 12 facilitates the outflow of the oxidant.

[0060] In one feasible solution, the cathode metal plate 13 and the anode metal plate 14 are connected by welding;

[0061] The welded welding line 6 surrounds the sealing boss 5 of the cathode metal plate 13 and the sealing boss 5 of the anode metal plate 14; the second protrusion 8 stops at a first preset distance from the welding line 6. It should be noted that the first preset distance can be selected according to the actual size of the bipolar plate.

[0062] The through hole 12 is preferably circular, and the distance between the welding wire 6 and the center of the through hole 12 is the sum of the first preset distance and the radius of the through hole 12 . This arrangement can ensure the sealing of the cathode metal plate 13 and the anode metal plate 14 .

[0063] The welding line 6 is also used to separate the fuel channel 2, the oxidant channel 3 and the coolant channel 4 into three areas.

[0064] After being separated by the welding line 6, the interiors of the fuel channel 2, the oxidant channel 3 and the coolant channel 4 are not interconnected, which can prevent the fuel, the oxidant and the coolant from mixing with each other before the fuel and the oxidant enter the reaction surface, thereby affecting the performance of the fuel cell.

[0065] The bipolar plate of the fuel cell provided in this embodiment forms a hollow cavity by relatively arranged sealing bosses 5 between the openings at both ends of the cathode metal plate 13 and the anode metal plate 14, and a wavy sealing interlayer 10 is arranged in the hollow cavity. On the basis of not hindering the circulation of fuel, oxidant and coolant, the support of the sealing boss is increased, the rigidity of the sealing boss is improved, plastic deformation is prevented at the sealing boss, and the risk of sealing failure is reduced. The structure is simple and easy to implement.

[0066] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A bipolar plate for a fuel cell, characterized in that: It comprises a first metal plate and a second metal plate, both ends of which are provided with openings for a fuel channel, an opening for an oxidant channel and an opening for a coolant channel; the first metal plate and the second metal plate are arranged opposite to each other; Sealing bosses are provided around the first metal plate and the second metal plate between the opposite openings at both ends; A hollow cavity is formed between the openings at both ends of the first metal plate and the second metal plate and between the oppositely arranged sealing bosses, and a sealing interlayer is also provided in the hollow cavity; along the port section of the first metal plate, the sealing interlayer is wavy.

2. The bipolar plate according to claim 1, characterized in that: The sealing boss is also provided around the side edges of the first metal plate and the second metal plate.

3. The bipolar plate according to claim 1, characterized in that: The oxidant channels of the first metal plate and the second metal plate include oxidant feed channels.

4. The bipolar plate according to claim 3, characterized in that: A plurality of first ridges are arranged side by side at both ends of the first metal plate, the first ridges are arranged near the end surface of the first metal plate and intersect with the sealing boss of the first metal plate; a plurality of second ridges are arranged side by side on the second metal plate and are opposite to the first ridges; the second ridges intersect with the sealing boss of the second metal plate; the first ridges and the second ridges form the oxidant feeding channel; and / or, the height of the first protrusion does not exceed the height of the sealing boss of the first metal plate and the height of the second protrusion does not exceed the height of the sealing boss of the second metal plate; And / or, the width of the oxidant feed channel is 0.5 mm-2 mm; And / or, the intervals between the oxidant feed channels are 1 mm to 2.5 mm.

5. The bipolar plate according to claim 4, characterized in that: The surface where the first metal plate and the second metal plate are bonded is the inner surface; the first ridge terminates after intersecting with the sealing boss of the first metal plate; the second ridge continues to extend toward the other end of the second metal plate after intersecting with the sealing boss of the second metal plate to form an extension portion; the extension portion does not exceed the central axis between the two end surfaces of the second metal plate; the extension portion and the inner surface of the first metal plate form a second cavity.

6. The bipolar plate according to claim 5, characterized in that: The first metal plate is provided with at least one through hole, and the edge of the through hole does not exceed the projection of the termination point of the extension portion of the second protrusion on the first metal plate; The oxidant feed channel, the wavy sealing interlayer, the second cavity and the through hole are connected to form the oxidant channel.

7. The bipolar plate according to claim 5, characterized in that: The first metal plate and the second metal plate are connected by welding; The welded welding line surrounds the sealing boss of the first metal plate and the sealing boss of the second metal plate; the second protrusion stops at a first preset distance from the welding line; The welding lines are used to separate the fuel channel, the oxidant channel and the coolant channel into regions that are not interconnected.

8. The bipolar plate according to claim 7, characterized in that: The surface of the first metal plate that is not in contact with the second metal plate is an outer surface, and a concave-convex groove is provided in the middle of the outer surface of the first metal plate, and the concave-convex groove is a gas flow channel.

9. The bipolar plate according to claim 8, characterized in that: The openings at both ends of the gas flow channel are communicated with the oxidant channel and the fuel channel respectively.

10. The bipolar plate according to claim 1, characterized in that: The first metal plate is a cathode metal plate, and the second metal plate is an anode metal plate.

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