A bipolar plate for use in a fuel cell

Abstract

The present invention discloses a bipolar plate for use in a fuel cell, comprising a main body substrate, wherein both upper and lower sides of the main body substrate are provided with shallow fluid grooves between the fuel medium flow holes, the shallow fluid grooves on the upper and lower sides are respectively connected with one of a pair of diagonal fuel medium flow holes, a plurality of deep foam placement grooves are provided between the shallow fluid grooves, the deep foam placement grooves are connected with the shallow fluid grooves on both sides, and a foam plate is provided in the deep foam placement grooves; a membrane layer patch is attached to one side of the main body substrate away from the shallow fluid grooves. The present invention adopts the arrangement of shallow fluid grooves and deep foam placement grooves, so that the gas transmission channel is more three-dimensional, the front fuel and oxidizing medium flow more evenly, and the contact with the intermediate membrane electrode is more sufficient, the thermal conductivity and heat dissipation performance is better, and through the siphon phenomenon, a comprehensive wetting phenomenon of the membrane electrode can be formed to prevent the membrane electrode from being partially dried out and overheated.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, in particular to a bipolar plate used in a fuel cell. Background Art

[0002] A fuel cell is a chemical device that converts the chemical energy of a fuel directly into electrical energy, also known as an electrochemical generator. It is the fourth power generation technology after hydroelectric power generation, thermal power generation, and atomic power generation. Since fuel cells convert the Gibbs free energy part of the chemical energy of the fuel into electrical energy through electrochemical reactions, they are not limited by the Carnot cycle effect, so they are highly efficient. In addition, fuel cells use fuel and oxygen as raw materials. At the same time, there are no mechanical transmission parts, so there is no noise pollution, and very few harmful gases are emitted. It can be seen that from the perspective of saving energy and protecting the ecological environment, fuel cells are the most promising power generation technology.

[0003] Bipolar plate, also known as current collector, is one of the important components of fuel cells. It has the following functions and properties: separation of fuel and oxidant, preventing gas from penetrating; collecting and conducting current, high conductivity; designed and processed flow channels, which can evenly distribute gas to the reaction layer of the electrode for electrode reaction; can discharge heat and keep the battery temperature field uniform; corrosion resistance; impact and vibration resistance; thin thickness; light weight; low cost, easy machining, suitable for batch manufacturing, etc.; bipolar plates need to be properly treated, bipolar plates need to have good conductivity, and not easily wetted by electrolytes, which can avoid electrolyte loss. The flexible contact of the bipolar plates outside the effective area of ​​the electrolyte diaphragm and the electrode can effectively prevent gas leakage, which is the so-called "wet seal". In order to reduce the corrosion of the bipolar plates in the "wet seal" area, the bipolar plates need to be protected.

[0004] Traditional bipolar plates are divided into graphite materials, metal materials and metal and graphite composite materials according to the processing materials. The front side of the bipolar plate is arranged with grooves for the flow of fuel or oxidant media, and the back side is arranged with grooves for cooling water. Especially on the front side, due to many requirements such as efficiency and fluidity, the surface grooves are densely distributed. The processing accuracy and processing volume of the processing scheme are very large. The use of compression molding to prepare the plate imposes certain restrictions on the mold and groove design. The back side of the bipolar plate is the cooling water side, which is usually prepared by machining or compression molding. Once any slight defect will cause the entire bipolar plate product to be scrapped, the scrap rate is high, so the preparation cost is high.

[0005] Therefore, how to prepare such fine grooves and the cooling water delivery grooves on the back to meet the flow of the medium, increase the contact with the bipolar plate membrane electrode while increasing the water absorption capacity, disperse the fluid, conduct energy, prepare separately, and reduce costs; to achieve the above purposes, the present invention discloses a bipolar plate for use in a fuel cell. Summary of the invention

[0006] An object of the present invention is to provide a bipolar plate for use in a fuel cell to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A bipolar plate for use in a fuel cell comprises a main body substrate, wherein four corners of the main body substrate are provided with fuel medium flow holes, the left and right sides of the main body substrate are provided with cooling water flow holes between the fuel medium flow holes, the upper and lower sides of the main body substrate are provided with fluid shallow grooves between the fuel medium flow holes, the fluid shallow grooves on the upper and lower sides are respectively connected with one pair of diagonal fuel medium flow holes, a plurality of foam placement deep grooves are provided between the fluid shallow grooves, the foam placement deep grooves are connected with the fluid shallow grooves on both sides, and foam plates are provided in the foam placement deep grooves;

[0009] A membrane layer patch is attached to the side of the main substrate away from the fluid shallow groove, and fuel medium membrane layer holes are opened through the four corners of the membrane layer patch corresponding to the fuel medium flow holes. Two cooling water membrane layer holes are opened through the membrane layer patch corresponding to the cooling water flow holes, and the two cooling water membrane layer holes are connected by a through-open flow channel group.

[0010] Preferably, the foam board is configured as a metal foam board.

[0011] Preferably, three deep grooves for placing foam are provided, and intervals are provided between the three deep grooves for placing foam.

[0012] Preferably, the main substrate is made of graphite or corrosion-resistant metal.

[0013] Preferably, the film layer patch is set to be a Teflon material patch or a metal patch, and the film layer patch is set to be 0.4 mm.

[0014] Preferably, the flow channel group includes a first flow channel, a second flow channel and a third flow channel leading out from the cooling water film layer hole on one side, and the first flow channel and the second flow channel are connected to the cooling water film layer hole on the other side through the main flow channel after being merged;

[0015] The third flow channel is sequentially divergently connected to a fourth flow channel, a fifth flow channel and a sixth flow channel, and the fourth flow channel, the fifth flow channel and the sixth flow channel are all connected to the main flow channel.

[0016] Preferably, the first flow channel, the second flow channel, the fourth flow channel, the fifth flow channel and the sixth flow channel are all distributed on the membrane layer patch in a bent shape.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention adopts the arrangement of shallow grooves for fluid and deep grooves for foam placement, so that the gas transmission channel is more three-dimensional, the front fuel and oxidizing medium flow more evenly, and the contact with the intermediate membrane electrode is more complete, the thermal conductivity and heat dissipation performance is better, and through the siphon phenomenon, the membrane electrode can be fully wetted to prevent the membrane electrode from local drying out and overheating.

[0019] The present invention adopts the use setting of the foam board. Since the foam usually has a certain thermal expansion capacity, when it expands, it can fully contact the membrane electrode of the fuel cell, thereby enhancing the thermal conductivity, electrical conductivity, and the water absorption capacity of the membrane electrode, so as not to produce a water film to prevent the gas from participating in the reaction; and when a metal foam board is used, the metal foam material itself has a certain conductive effect, which can further improve the conductive efficiency.

[0020] The main substrate of the present invention does not require any micro-groove processing, is easier to prepare, and has easier surface modification processes, such as corrosion-resistant treatment, hydrophobic treatment, wetting treatment, etc. on the surface. Moreover, since the main substrate and the foam board are processed separately, the processing difficulty is greatly reduced, and the production efficiency and the qualified rate are reduced.

[0021] The back side of the main substrate of the present invention adopts a film-sticking method to set the cooling water flow channel. The flow, corrosion and sealing requirements on this side are extremely low. The film-sticking method is easier to implement than the back grooving method, which reduces the processing of the main substrate and reduces the risk factor of quality damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the front structure of the main substrate of the present invention;

[0023] Figure 2 It is a schematic diagram of the back structure of the main substrate of the present invention;

[0024] Figure 3 For the present invention Figure 1 A section structural sectional view;

[0025] Figure 4 For the present invention Figure 1 Middle B section structural cutaway view;

[0026] Figure 5 It is a schematic diagram of the surface structure of the film patch of the present invention;

[0027] Figure 6 It is a schematic diagram of the connection between the main substrate and the film layer patch of the present invention.

[0028] In the figure: 1 main substrate, 2 membrane patch, 3 fuel medium flow hole, 4 cooling water flow hole, 5 fluid shallow groove, 6 foam placement deep groove, 7 foam plate, 8 fuel medium membrane layer hole, 9 cooling water membrane layer hole, 101 first flow channel, 102 second flow channel, 103 third flow channel, 104 main flow channel, 105 fourth flow channel, 106 fifth flow channel, 107 sixth flow channel. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-6 , the present invention provides a technical solution:

[0031] A bipolar plate for use in a fuel cell comprises a main substrate 1, wherein the main substrate 1 is configured to be made of graphite or a corrosion-resistant metal, which can function as the main material of the bipolar plate. The four corners of the main substrate 1 are all provided with fuel medium flow holes 3, and there are four fuel medium flow holes 3, which are distributed at the four corners and all pass through the main substrate 1. The left and right sides of the main substrate 1 are provided with cooling water flow holes 4 between the fuel medium flow holes 3, and the cooling water flow holes 4 are used for cooling water flow, and there are two cooling water flow holes 4, which pass through the main substrate 1. The upper and lower sides of the main substrate 1 are provided with fluid shallow grooves 5 between the fuel medium flow holes 3, and there are two upper and lower fluid shallow grooves 5, and the fluid shallow grooves 5 on the upper and lower sides are respectively connected with one pair of diagonal fuel medium flow holes 3. In this embodiment, the fuel medium flow hole 3 at the upper right corner is connected to the upper fluid shallow groove 5, and the fuel medium flow hole 3 at the lower left corner is connected to the lower fluid shallow groove 5, and a plurality of foam placement deep grooves 6 are provided between the fluid shallow grooves 5, as shown in the attached manual. Figure 1 As shown, three foam placement deep grooves 6 are provided, and intervals are provided between the three foam placement deep grooves 6. The foam placement deep grooves 6 are connected to the fluid shallow grooves 5 on both sides. The groove depth of the foam placement deep grooves 6 is greater than the groove depth of the fluid shallow grooves 5. A foam plate 7 is provided in the foam placement deep grooves 6. The material of the foam plate 7 can be a metal foam plate or a foam plate of other materials. The flow transmission function through the fluid shallow grooves 5 and the foam placement deep grooves 6 is carried out according to the attached Figure 1 The arrows in the figure indicate the flow direction of the positive fuel or oxidant.

[0032] The main substrate 1 is provided with a film patch 2 on one side away from the fluid shallow groove 5. The film patch 2 is set as a Teflon material patch or a metal patch, and the film patch 2 is set to 0.4 mm. The surfaces on both sides of the structure are completely the same. The structure is as shown in the attached manual. Figure 5 As shown, fuel medium membrane holes 8 are provided at the four corners of the membrane patch 2 corresponding to the fuel medium flow holes 3, and two cooling water membrane holes 9 are provided on the membrane patch 2 corresponding to the cooling water flow holes 4. All the holes on the membrane patch 2 are arranged in a hollow manner and are pasted on the back of the main substrate 1 in a manner similar to a sticker, that is, the membrane patch 2 is connected in the form of a film, and is connected to the back of the main substrate 1. It is first fixed with tape and then the tape is torn off. The process technology is very mature and efficient. After all the membrane patches 2 are pasted and fixed on the back of the main substrate 1 of the bipolar plate, they will form a flow channel space with the back of the main substrate 1, so that the hollow flow channels of the flow channel group can realize the flow of cooling water.

[0033] The two cooling water film layer holes 9 are connected by a flow channel group that is opened through, and the flow channel group includes a first flow channel 101, a second flow channel 102 and a third flow channel 103 that are led out from the cooling water film layer hole 9 on one side. The first flow channel 101 and the second flow channel 102 are connected to the cooling water film layer hole 9 on the other side through the main flow channel 104 after being converged. The third flow channel 103 is sequentially connected with a fourth flow channel 105, a fifth flow channel 106 and a sixth flow channel 107. The fourth flow channel 105, the fifth flow channel 106 and the sixth flow channel 107 are connected in sequence. The first flow channel 101, the second flow channel 102, the third flow channel 103, the main flow channel 104, the fourth flow channel 105, the fifth flow channel 106 and the sixth flow channel 107 formed with the main substrate 1 are used to realize the function of cooling water, wherein the first flow channel 101, the second flow channel 102, the fourth flow channel 105, the fifth flow channel 106 and the sixth flow channel 107 are all bent and distributed on the film layer patch 2, and the cooling water passes through the film layer patch 2 as shown in the attached manual. Figure 5 The water flows in the direction of the arrow shown, and the cooling effect can be improved by the bent structural distribution. Moreover, the back side of the main substrate 1 of the bipolar plate is the cooling water side. In the prior art, it is prepared by machining or compression molding. Once any slight defect occurs, the entire main substrate 1 will be scrapped, so the scrap rate is high and the preparation cost is high. However, in the present invention, the film pasting method is adopted, and there is no need to perform grooving on the back side of the main substrate 1, thereby reducing the scrap rate.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A bipolar plate for use in a fuel cell, comprising a main substrate (1), characterized in that: The four corners of the main substrate (1) are provided with fuel medium flow holes (3), the left and right sides of the main substrate (1) are provided with cooling water flow holes (4) between the fuel medium flow holes (3), the upper and lower sides of the main substrate (1) are provided with fluid shallow grooves (5) between the fuel medium flow holes (3), the fluid shallow grooves (5) on the upper and lower sides are respectively connected to one of the diagonal fuel medium flow holes (3), a plurality of foam placement deep grooves (6) are provided between the fluid shallow grooves (5), the foam placement deep grooves (6) are connected to the fluid shallow grooves (5) on both sides, and foam plates (7) are provided in the foam placement deep grooves (6); The main substrate (1) is provided with a membrane patch (2) on one side away from the fluid shallow groove (5), and the four corners of the membrane patch (2) are provided with fuel medium membrane holes (8) corresponding to the fuel medium flow holes (3), and the membrane patch (2) is provided with two cooling water membrane holes (9) corresponding to the cooling water flow holes (4), and the two cooling water membrane holes (9) are connected by a through-flow channel group.

2. A bipolar plate for use in a fuel cell according to claim 1, characterized in that: The foam plate (7) is configured as a metal foam plate.

3. A bipolar plate for use in a fuel cell according to claim 1, characterized in that: The three deep foam placement grooves (6) are provided, and intervals are provided between the three deep foam placement grooves (6).

4. A bipolar plate for use in a fuel cell according to claim 1, characterized in that: The main substrate (1) is made of graphite or corrosion-resistant metal.

5. A bipolar plate for use in a fuel cell according to claim 1, characterized in that: The film layer patch (2) is configured as a Teflon material patch or a metal patch, and the film layer patch (2) is configured to be 0.4 mm.

6. A bipolar plate for use in a fuel cell according to claim 1, characterized in that: The flow channel group comprises a first flow channel (101), a second flow channel (102) and a third flow channel (103) which are led out from the cooling water film layer hole (9) on one side, and the first flow channel (101) and the second flow channel (102) are connected to the cooling water film layer hole (9) on the other side through the main flow channel (104) after being merged. The third flow channel (103) is sequentially connected to a fourth flow channel (105), a fifth flow channel (106) and a sixth flow channel (107), and the fourth flow channel (105), the fifth flow channel (106) and the sixth flow channel (107) are all connected to the main flow channel (104).

7. A bipolar plate for use in a fuel cell according to claim 6, characterized in that: The first flow channel (101), the second flow channel (102), the fourth flow channel (105), the fifth flow channel (106) and the sixth flow channel (107) are all distributed in a bent shape on the membrane layer patch (2).

Images