Fuel cell metal bipolar plate and fuel cell

Abstract

The present invention discloses a fuel cell metal bipolar plate and a fuel cell, wherein the fuel cell metal bipolar plate comprises a cathode plate (25), an anode plate (24), and a coolant flow field (28) formed between the cathode plate (25) and the anode plate (24), wherein a plurality of parallel wavy flow channels (23) are arranged in the middle of the cathode plate (25), and a plurality of parallel straight flow channels (22) are arranged in the middle of the anode plate (24). The fuel cell metal bipolar plate of the present invention can allow the reaction gas to flow evenly in the flow field, so that the reaction is sufficient, thereby improving the output performance of the fuel cell.

Description

Technical Field

[0001] The present invention relates to a fuel cell, and in particular to a metal bipolar plate for a fuel cell and a fuel cell comprising the bipolar plate. Background Art

[0002] As the core component of fuel cells, bipolar plates not only have the functions of collecting current and supporting membrane electrodes, but also play the role of evenly distributing the reaction gas. Metal bipolar plates are generally made of two metal plates through welding, and the metal plates are formed by stamping stainless steel metal sheets. There are flow areas formed by the combination of gas flow channels on them, and a coolant flow space is formed between the two plates.

[0003] The two plates are composed of an anode plate and a cathode plate. The anode plate is provided with a fuel flow area, and the fuel diffuses to the anode catalyst layer through the flow channel; the cathode plate is provided with an oxidant flow area, and the oxidant diffuses to the cathode catalyst layer through the flow channel.

[0004] The flow field structures of the cathode plate and anode plate of traditional fuel cells are the same, both consisting of multiple parallel direct current channels, which have the following problems:

[0005] In a hydrogen-oxygen fuel cell, oxygen flows in the cathode plate and hydrogen flows in the anode plate. Since the diffusion rate of hydrogen is much greater than that of oxygen (about 4 times that of oxygen) and the demand for hydrogen is less than that of oxygen, the rate at which hydrogen diffuses through the flow channel on the anode plate to the anode catalyst layer is faster than the rate at which oxygen diffuses through the flow channel on the cathode plate to the cathode catalyst layer. In addition, since the flow field structure of the cathode plate and the anode plate is the same, the supply rate of oxygen cannot match the supply rate of hydrogen, and as a result, some of the hydrogen that has entered fails to participate in the reaction, resulting in uneven gas distribution and insufficient reaction, which in turn reduces the output performance of the fuel cell. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a fuel cell metal bipolar plate, which can allow the reaction gas to flow evenly in the flow field, so that the reaction is sufficient, thereby improving the output performance of the fuel cell.

[0007] The present invention also provides a fuel cell comprising the above fuel cell metal bipolar plate, and the output performance of the fuel cell is stable.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A fuel cell metal bipolar plate comprises a cathode plate, an anode plate and a coolant flow field formed between the cathode plate and the anode plate, characterized in that a plurality of parallel wavy flow channels are arranged in the middle of the cathode plate, and a plurality of parallel straight flow channels are arranged in the middle of the anode plate.

[0010] The working principle of the above fuel cell metal bipolar plate is:

[0011] When the fuel cell is working, the hydrogen on the anode plate diffuses through the flow channel on the anode plate to

[0012] The anode catalyst layer decomposes into hydrogen ions and releases electrons. The oxygen on the cathode plate at the other end diffuses to the cathode catalyst layer through the flow channel on the cathode plate. At the same time, the hydrogen ions combine with the oxygen that has reached the cathode catalyst layer to generate water. In the whole process, the fuel and oxidant are supplied externally for reaction. As long as the reactants are continuously input and the products are continuously discharged, the fuel cell can continuously generate electricity.

[0013] Since the diffusion rate of hydrogen is much greater than that of oxygen, based on this principle, the present invention adopts a straight flow channel on the anode plate and a wavy flow channel on the cathode plate, wherein the introduced hydrogen flows on the straight flow channel, and the introduced oxygen flows on the wavy flow channel. Since the cathode plate is provided with a wavy flow channel, oxygen can form turbulence during the flow process, which is a multi-directional chaotic flow state, which is more conducive to increasing the rate of oxygen diffusion to the cathode catalyst layer, reacting with hydrogen ions, making the reaction sufficient, and improving the output performance of the fuel cell.

[0014] Preferably, the cathode plate and the anode plate are rectangular structures, wherein the wavy flow channel on the cathode plate is arranged along the width direction of the cathode plate, and the straight flow channel on the anode plate is arranged along the length direction of the anode plate. The purpose is that the flow field structure of the cathode plate generates water during operation, and by arranging the wavy flow channel along the width direction of the cathode plate, the length of the wavy flow channel is shorter, which is conducive to the timely discharge of water and improves the output performance of the fuel cell.

[0015] Preferably, the cathode plate and the anode plate are connected together with their backs facing each other, the middle area of ​​the cathode plate facing outward forms a wavy flow channel, and the middle area of ​​the anode plate facing outward forms a straight flow channel. In this way, a plurality of bipolar plates of the present invention are connected in series, a membrane electrode is arranged between the bipolar plates, and the cathode plate, anode plate and membrane electrode between two adjacent bipolar plates constitute the basic power generation components of the fuel cell, thereby forming a fuel cell composed of a plurality of power generation components.

[0016] Preferably, the wavy flow channel on the cathode plate is formed by punching the back side of the cathode plate toward the front side along the width direction, and the concave area on the back side of the cathode plate forms a wavy cooling flow channel; the straight flow channel on the anode plate is formed by punching the back side of the anode plate toward the front side along the length direction, and the concave area on the back side of the anode plate forms a straight cooling flow channel; the wavy cooling flow channel and the straight cooling flow channel are combined to form the coolant flow field. With the above structure, the coolant flow field is formed while the wavy flow channel and the straight flow channel are formed by stamping, which makes the processing simpler and saves costs.

[0017] Preferably, of the two edges in the length direction of the cathode plate and the anode plate, one edge is provided with an air inlet, and the other edge is provided with an air outlet; of the two edges in the width direction of the cathode plate and the anode plate, one edge is provided with a hydrogen inlet and a coolant inlet, and the other edge is provided with a hydrogen outlet and a coolant outlet. The advantage of adopting the above structure is that, since the air intake volume is large, by arranging the air inlet and the air outlet in the length direction, there is enough setting space, which is conducive to the uniform delivery of air and adapts to the delivery volume of air; since the hydrogen intake volume is small, by arranging the hydrogen inlet and the hydrogen outlet in the width direction, the hydrogen delivery can be met; at the same time, the coolant inlet and

[0018] The coolant outlet is also arranged in the width direction, so that on the one hand, the overall flow direction of the coolant in the coolant flow field is along the length direction, which is consistent with the direction of the straight flow channel, which is beneficial to reducing the flow resistance of the coolant, thereby facilitating heat exchange with the reaction heat, so that the temperature distribution of each pole on the membrane electrode surface is uniform; on the other hand, since the coolant flow field is a grid-like space composed of a combination of wavy cooling channels and straight cooling channels, the cooling effect can also be improved.

[0019] Preferably, the air inlet, air outlet, hydrogen inlet, hydrogen outlet, coolant inlet and coolant outlet penetrate the cathode plate and anode plate connected together. In this way, the working fluid inlet of multiple bipolar plates combined together is shared, which is convenient for the transportation of working fluid.

[0020] Preferably, the hydrogen inlet is arranged in the middle, and the coolant inlets are arranged on both sides of the hydrogen inlet; the hydrogen outlet is arranged in the middle, and the coolant outlets are arranged on both sides of the hydrogen outlet.

[0021] Preferably, reinforcing ribs are provided at the coolant inlet and the coolant outlet to support the bipolar plates and make the distribution of the coolant more uniform.

[0022] Preferably, a gas guide area is provided between the hydrogen inlet and the hydrogen outlet and the direct flow channel, and the gas guide area is provided with a guide structure to ensure uniform gas distribution, thereby making the reaction more complete.

[0023] Preferably, the flow-guiding structure is composed of a plurality of protrusions uniformly arranged along a direction perpendicular to the flow direction of the hydrogen.

[0024] Preferably, positioning holes of the same size are provided at the four top corners of the cathode plate and the anode plate.

[0025] A fuel cell comprises the fuel cell metal bipolar plate.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention sets a straight flow channel on the anode plate and a wavy flow channel on the cathode plate, so as to make an adaptive design of the flow channel according to the characteristics of oxygen and hydrogen, so that the diffusion rate of oxygen and hydrogen can reach a balance with the reaction between oxygen and hydrogen, making the chemical reaction more sufficient, thereby improving the power generation efficiency and output performance of the fuel cell.

[0028] 2. The present invention allows the chemical reaction of the fuel cell to be more complete, thereby preventing local overheating caused by incomplete reaction and improving the output performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 and Figure 2 Schematic diagram of the structure of the metal bipolar plate of the fuel cell according to the first embodiment of the present invention, wherein: Figure 1 This is the front view of the cathode plate side. Figure 2 It is a front view of one side of the anode plate;

[0030] Figure 3 and Figure 4 This is an exploded view of a fuel cell metal bipolar plate according to Example 1 of the present invention;

[0031] Figure 5 for Figure 1 A partial enlarged view of

[0032] Figure 6 for Figure 2 A partial enlarged view of

[0033] Figure 7 for Figure 3 A partial enlarged view of the middle cathode plate;

[0034] Figure 8 for Figure 3 A partial enlarged view of the middle anode plate;

[0035] Fig. 9 for Figure 4 A partial enlarged view of the middle cathode plate;

[0036] Fig.10 for Figure 4 A partial enlarged view of the middle anode plate;

[0037] In the figure: 1, coolant outlet; 2, positioning hole; 3, air inlet; 4, air inlet; 5, air inlet; 6, air inlet; 7, positioning hole; 8, coolant inlet; 9, hydrogen inlet; 10, coolant inlet; 11, positioning hole; 12, air outlet; 13, air outlet; 14, air outlet; 15, air outlet; 16, reinforcing rib; 17, positioning hole; 18, coolant outlet; 19, guide area; 20, guide structure; 21, hydrogen outlet; 22, straight channel; 23, wavy channel; 24, anode plate; 25, cathode plate; 26, straight cooling channel;

[0038] 27. Wave-shaped cooling channel; 28. Coolant flow field. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0040] Example 1

[0041] See also Figure 1-4 As shown, the metal bipolar plate of the fuel cell of the present invention comprises a cathode plate 25, an anode plate 24 and a coolant flow field 28 formed between the cathode plate 25 and the anode plate 24. Among them, a plurality of parallel wavy flow channels 23 are arranged in the middle of the cathode plate 25, and a plurality of parallel straight flow channels 22 are arranged in the middle of the anode plate 24.

[0042] See also Figure 1 and Figure 2 As shown, the cathode plate 25 and the anode plate 24 are both rectangular structures, wherein the wavy flow channel 23 on the cathode plate 25 is arranged along the width direction of the cathode plate 25, and the straight flow channel 22 on the anode plate 24 is arranged along the length direction of the anode plate 24. The purpose is that the flow field structure of the cathode plate 25 generates water during operation, and by arranging the wavy flow channel 23 along the width direction of the cathode plate 25, the length of the wavy flow channel 23 is shorter, which is conducive to the timely discharge of water and improves the performance of the fuel cell.

[0043] See also Figure 3 and Figure 4As shown, the cathode plate 25 and the anode plate 24 are connected together with their backs facing each other, for example, fixedly connected by welding, the middle area of ​​the cathode plate 25 facing outward forms a wavy flow channel 23, and the middle area of ​​the anode plate 24 facing outward forms a straight flow channel 22. In this way, a plurality of bipolar plates of the present invention are connected in series, a membrane electrode is arranged between the bipolar plates, and the cathode plate 25, the anode plate 24 and the membrane electrode in the middle between two adjacent bipolar plates constitute the basic power generation components of the fuel cell, thereby constituting a fuel cell composed of a plurality of power generation components.

[0044] See also Figure 3-4 and Figure 7-10 As shown, the wavy flow channel 23 on the cathode plate 25 is formed by punching the back side of the cathode plate 25 toward the front side along the width direction, and the concave area on the back side of the cathode plate 25 forms a wavy cooling flow channel 27; the straight flow channel 22 on the anode plate 24 is formed by punching the back side of the anode plate 24 toward the front side along the length direction, and the concave area on the back side of the anode plate 24 forms a straight cooling flow channel 26; the wavy cooling flow channel 27 and the straight cooling flow channel 26 are combined to form the coolant flow field 28. With the above structure, the coolant flow field 28 is also formed while the wavy flow channel 23 and the straight flow channel 22 are formed by stamping, making the processing simpler and saving costs.

[0045] See also Figure 1 and Figure 2As shown, at two edges in the length direction of the cathode plate 25 and the anode plate 24, a plurality of air inlets 3, 4, 5, 6 are arranged on one edge, and a plurality of air outlets 12, 13, 14, 15 are arranged on the other edge; at two edges in the width direction of the cathode plate 25 and the anode plate 24, a hydrogen inlet 9 and a coolant inlet 8, 10 are arranged on one edge, wherein the hydrogen inlet 9 is arranged in the middle, and the coolant inlets 8, 10 are arranged on both sides of the hydrogen inlet 9; the hydrogen outlet 21 is arranged in the middle, and the coolant outlets 1, 18 are arranged on both sides of the hydrogen outlet 21. Since the air intake volume is large, multiple air inlets 3, 4, 5, 6 and multiple air outlets 12, 13, 14, 15 are respectively arranged in the length direction so as to have sufficient setting space, and it is beneficial to uniformly transport the air and adapt to the air transport volume; since the hydrogen intake volume is small, the hydrogen inlet 9 and the hydrogen outlet 21 are respectively arranged in the width direction to meet the hydrogen transport; at the same time, the coolant inlet 8, 10 and the coolant outlet 1, 18 are also respectively arranged in the width direction, so that on the one hand, the overall flow direction of the coolant in the coolant flow field 28 is along the length direction, and the length direction is consistent with the direction of the straight channel 22, which is beneficial to reduce the flow resistance of the coolant, and on the other hand, since the coolant flow field 28 is a grid-like space composed of a wave-shaped cooling channel 27 and a straight cooling channel 26, the cooling effect can also be improved.

[0046] See also Figure 1-10 As shown, the air inlet 3, 4, 5, 6, air outlet 12, 13, 14, 15, hydrogen inlet 9, hydrogen outlet 21, coolant inlet 8, 10 and coolant outlet 1, 18 penetrate the cathode plate 25 and the anode plate 24 connected together in the thickness direction, and are connected to the corresponding channels at the corresponding positions in the thickness direction. For example, the air inlet 3, 4, 5, 6 and air outlet 12, 13, 14, 15 are connected to the wavy flow channel 23 at the thickness position corresponding to the wavy flow channel 23 of the cathode plate 25, the hydrogen inlet 9 and the hydrogen outlet 21 are connected to the straight flow channel 22 at the thickness position corresponding to the straight flow channel 22 of the anode plate 24, and the coolant inlet 8, 10 and the coolant outlet 1, 18 are connected to the coolant flow field 28 at the position connected between the cathode plate 25 and the anode plate 24. In this way, the working medium inlet of the multiple bipolar plates combined together are all shared, which is convenient for the transportation of the working medium.

[0047] See also Figure 1-2 As shown, the coolant inlets 8, 10 and the coolant outlets 1, 18 are provided with reinforcing ribs 16 for supporting the bipolar plates and making the distribution of the coolant more uniform. The reinforcing ribs 16 can be formed on the cathode plate 25 and / or the anode plate 24 by stamping.

[0048] See also Figure 2 , Figure 6 , Figure 8 as well as Fig. 9 As shown, a gas guide area 19 is provided between the hydrogen inlet 9 and the hydrogen outlet 21 and the direct current channel 22, and the gas guide area 19 is provided with a guide structure 20, so that the gas is evenly distributed, thereby achieving sufficient reaction. The guide structure 20 is composed of a plurality of protrusions evenly arranged along a direction perpendicular to the flow of hydrogen. When hydrogen flows through the protrusions, it is evenly dispersed and then enters the direct current channel 22.

[0049] See also Figure 1-2 As shown, the four corners of the cathode plate 25 and the anode plate 24 are respectively provided with positioning holes 2, 7, 11, 17 of the same size. This makes the cathode plate 25 and the anode plate 24 more firm and more accurately positioned.

[0050] Example 2

[0051] The difference between this embodiment and embodiment 1 is that, in this embodiment, the positions of the air inlets 3, 4, 5, 6 and the air outlets 12, 13, 14, 15 in embodiment 1 are interchanged, the positions of the hydrogen inlet 9 and the hydrogen outlet 21 are interchanged, and the positions of the coolant inlets 8, 10 and the coolant outlets 1, 18 are interchanged.

[0052] Other implementations of this embodiment other than those described above may be carried out with reference to Embodiment 1.

[0053] Example 3

[0054] The difference between this embodiment and the first embodiment is that, in this embodiment, the wavy flow channel and the straight flow channel are both arranged along the length direction of the cathode plate and the anode plate.

[0055] Other implementations of this embodiment other than those described above may be carried out with reference to Embodiment 1.

[0056] Example 4

[0057] This embodiment provides a fuel cell, which includes the fuel cell metal bipolar plate of the present invention.

[0058] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A fuel cell metal bipolar plate, comprising a cathode plate (25), an anode plate (24) and a coolant flow field (28) formed between the cathode plate (25) and the anode plate (24), characterized in that: A plurality of parallel wavy flow channels (23) are arranged in the middle of the cathode plate (25), and a plurality of parallel straight flow channels (22) are arranged in the middle of the anode plate (24); the cathode plate (25) and the anode plate (24) are rectangular structures, wherein the wavy flow channels (23) on the cathode plate (25) are arranged along the width direction of the cathode plate (25), and the straight flow channels (22) on the anode plate (24) are arranged along the length direction of the anode plate (24); The wavy flow channel (23) on the cathode plate (25) is formed by punching the back side of the cathode plate (25) toward the front side along the width direction, and the recessed area on the back side of the cathode plate (25) forms a wavy cooling flow channel (27); the straight flow channel (22) on the anode plate (24) is formed by punching the back side of the anode plate (24) toward the front side along the length direction, and the recessed area on the back side of the anode plate (24) forms a straight cooling flow channel (26); the wavy cooling flow channel (27) and the straight cooling flow channel (26) are combined together to form the coolant flow field (28); Of the two edges in the length direction of the cathode plate (25) and the anode plate (24), one edge is provided with an air inlet (3, 4, 5, 6), and the other edge is provided with an air outlet (12, 13, 14, 15); of the two edges in the width direction of the cathode plate (25) and the anode plate (24), one edge is provided with a hydrogen inlet (9) and a coolant inlet (8, 10), and the other edge is provided with a hydrogen outlet (21) and a coolant outlet (1, 18).

2. The fuel cell metal bipolar plate according to claim 1, characterized in that: The cathode plate (25) and the anode plate (24) are connected together with their backs facing each other, the middle area of ​​the cathode plate (25) facing outward forms a wavy flow channel (23), and the middle area of ​​the anode plate (24) facing outward forms a straight flow channel (22).

3. The fuel cell metal bipolar plate according to claim 1, characterized in that: The hydrogen inlet (9) is arranged in the middle, and the coolant inlets (8, 10) are arranged on both sides of the hydrogen inlet (9); the hydrogen outlet (21) is arranged in the middle, and the coolant outlets (1, 18) are arranged on both sides of the hydrogen outlet (21).

4. The fuel cell metal bipolar plate according to claim 1, characterized in that: Reinforcing ribs (16) are provided at the coolant inlet (8, 10) and the coolant outlet (1, 18).

5. The fuel cell metal bipolar plate according to claim 1, characterized in that: A gas guide area (19) is provided between the hydrogen inlet (9), the hydrogen outlet (21) and the direct flow channel (22), and the gas guide area (19) is provided with a guide structure (20).

6. The fuel cell metal bipolar plate according to claim 5, characterized in that: The flow-guiding structure (20) is composed of a plurality of protrusions uniformly arranged along a direction perpendicular to the flow direction of the hydrogen.

7. The fuel cell metal bipolar plate according to any one of claims 1, 5-6, characterized in that: Positioning holes (2, 7, 11, 17) of the same size are arranged at the four top corners of the cathode plate (25) and the anode plate (24).

8. A fuel cell, characterized in that: A fuel cell metal bipolar plate comprising any one of claims 1 to 7.

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