Metal bipolar plate capable of increasing trench depth

Abstract

The utility model relates to the technical field of fuel cells, in particular to a metal bipolar plate for increasing trench depth, which comprises a body and two gas diffusion layers respectively arranged at two ends of the body, a metal screen plate is arranged between the body and at least one gas diffusion layer, the body is provided with a plurality of ridges, and the ridges are arranged on the body. The metal mesh plate is provided with a plurality of first mesh strips, and the first mesh strips and the ridge strips are in one-to-one correspondence and coincide in a profiling mode or in a projection mode so that the groove depth between the adjacent ridge strips can be increased. According to the utility model, the metal screen plate is additionally arranged between the body and the gas diffusion layer, so that the corners of the ridges are changed from round corners to right angles (non-round corners) of the net strips, and the effective contact area with a membrane electrode is increased; according to the metal net plate, the depth of a groove (namely the position between the two ridge strips) is increased due to the first net strips, and the effect of increasing the depth of the groove is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to a metal bipolar plate with increased groove depth. Background Art

[0002] In a fuel cell, a bipolar plate is one of the core components. Classified according to materials, it is mainly divided into a metal-based bipolar plate and a carbon-based bipolar plate. Compared with the carbon-based bipolar plate, since the metal-based bipolar plate (hereinafter referred to as the metal bipolar plate) is made by an etching process or a stamping process, its thickness can be made smaller than that of the carbon-based bipolar plate.

[0003] However, compared with the carbon-based bipolar plate, the current metal bipolar plate has the following deficiencies:

[0004] 1. The corners of the flow channel ridges and grooves of the carbon-based bipolar plate do not form rounded corners. However, for the metal bipolar plate, especially the metal bipolar plate formed by stamping, the corners of the ridges and grooves after forming are more likely to form rounded corners. Under the same pitch, the side length of the rounded corner structure is smaller than that of the right-angle structure. This results in a smaller effective contact area between the flow field ridge and the membrane electrode compared to the right angle. A smaller contact area will cause an increase in the internal resistance of the fuel cell and a decrease in the output voltage under the same current density.

[0005] 2. With the continuous increase in power density, the requirement for the flow field pitch of the bipolar plate design is getting smaller and smaller. When the metal bipolar plate is formed, the depth of the flow field groove is limited by the elongation rate of the metal material and cannot achieve a deeper groove depth. Summary of the Utility Model

[0006] The utility model provides a metal bipolar plate with increased groove depth for the problems of the prior art, which can achieve rounded corners at the corners of the ridges and grooves, increased groove depth, and uniform oxygen concentration in the air in the flow field grooves.

[0007] To solve the above technical problems, the utility model adopts the following technical solutions:

[0008] A metal bipolar plate with increased groove depth provided by the utility model includes a body and two gas diffusion layers respectively arranged at both ends of the body. A metal mesh plate is arranged between the body and at least one gas diffusion layer. The body is provided with a plurality of ridge bars, and the metal mesh plate is provided with a plurality of first mesh bars. The first mesh bars and the ridge bars are in one-to-one correspondence and are in imitation coincidence or projection coincidence to increase the groove depth between adjacent ridge bars.

[0009] Furthermore, the body and the metal mesh plate are fixedly connected by any one of the following methods: bonding with conductive adhesive, soldering, laser welding, or resistance welding.

[0010] Further, the body includes an anode plate and a cathode plate. The anode plate and the cathode plate each have multiple ridge bars and several groove bars. The adjacent ridge bars are connected by the groove bars. The groove bars of the anode plate are connected to the groove bars of the cathode plate in a one-to-one correspondence, and the ridge bars of the anode plate and the ridge bars of the cathode plate are arranged back to back in a one-to-one correspondence.

[0011] The ridge bars of the anode plate and the ridge bars of the cathode plate respectively coincide with the first mesh bars of the two metal mesh plates in a one-to-one correspondence by profiling or projection.

[0012] Furthermore, the mesh plate is further provided with multiple second mesh bars. The second mesh bars are arranged parallel to the first mesh bars. The second mesh bars are located between two adjacent ridge bars and are spaced from the groove bars.

[0013] Furthermore, the connection part between the ridge bar and the groove bar is an arc structure.

[0014] Further, the number of the metal mesh plates is two, and the two metal mesh plates are respectively arranged on the upper surface and the lower surface of the body.

[0015] Further, the metal mesh plate is fixedly connected to the cathode plate.

[0016] Advantages of the present utility model:

[0017] 1. By adding a layer of metal mesh plate between the body and the gas diffusion layer, the present utility model changes the rounded corners at the edges and corners of the ridges into right angles (non-rounded corners) of the mesh plate, thereby increasing the effective contact area with the membrane electrode.

[0018] 2. By adding a layer of metal mesh plate between the body and the gas diffusion layer, the present utility model increases the depth of the groove (i.e., the position between two ridge bars) due to the first mesh bar, achieving the effect of increasing the groove depth. Description of the drawings

[0019] Figure 1 is a schematic structural diagram of the present utility model.

[0020] Figure 2 is a schematic diagram of another embodiment of the present utility model.

[0021] Reference numerals: 1 - body, 2 - gas diffusion layer, 3 - metal mesh plate, 4 - ridge bar, 5 - first mesh bar, 6 - anode plate, 7 - cathode plate, 8 - groove bar, 9 - second mesh bar. Detailed implementation manners

[0022] For the convenience of understanding by those skilled in the art, the present utility model will be further described below in conjunction with embodiments and the drawings. The content mentioned in the embodiments does not limit the present utility model. The present utility model will be described in detail below with reference to the drawings.

[0023] As shown Figure 1 in the figure, a metal bipolar plate with a high groove depth-width ratio provided by the present utility model includes a body 1 and two gas diffusion layers 2 respectively arranged at both ends of the body 1. A metal mesh plate 3 is arranged between the body 1 and at least one gas diffusion layer 2. The body 1 is provided with a plurality of ridges 4, and the metal mesh plate 3 is provided with a plurality of first mesh strips 5. The first mesh strips 5 and the ridges 4 are in one-to-one correspondence and are in imitation coincidence or projection coincidence to increase the groove depth between adjacent ridges 4.

[0024] The preparation process of the metal bipolar plate is as follows:

[0025] A. Form the body 1 with ridges 4 by etching or stamping processes;

[0026] B. Prepare the metal mesh plate 3 with mesh strips, where the shapes of the mesh strips correspond to the shapes of the ridges 4 one by one;

[0027] C. Arrange the metal mesh plate 3 on at least one surface of the body 1, and make the mesh strips of the metal mesh plate 3 and the ridges 4 of the body 1 in one-to-one correspondence and in imitation coincidence or projection coincidence;

[0028] D. Fix the body 1 and the metal mesh plate 3;

[0029] E. Arrange the gas diffusion layer 2.

[0030] During actual production, according to needs, a metal mesh plate 3 with a suitable thickness can be selected, and it can be decided to arrange the metal mesh plate 3 on one surface or both the upper and lower surfaces of the body 1. Due to problems such as the ductility and strength of the metal material, the groove depth of the metal is limited; while the present utility model overcomes the metal material problem and increases the groove depth by additionally installing the metal mesh plate 3 and making the first mesh strips 5 of the metal mesh plate 3 in imitation coincidence or projection coincidence with the ridges 4 of the body 1, which is equivalent to stacking the first mesh strips 5 on the ridges 4.

[0031] The metal mesh plate 3 is preferably made by at least one of laser cutting, etching, blanking, and weaving processes. For the metal mesh plate 3 made in the above way, the side edges of its first mesh strips 5 are necessarily non-rounded corners and are usually right angles. Therefore, for the groove formed after the first mesh strips 5 are stacked, in addition to the increased depth, the corner positions of the groove change from the rounded corner positions of the ridges 4 to the right angle positions of the mesh strips, achieving an increase in the effective contact area with the membrane electrode.

[0032] In this embodiment, the body 1 and the metal mesh plate 3 are fixedly connected by any one of conductive adhesive bonding, soldering, laser welding, and resistance welding. That is, after the body 1 and the metal mesh are installed in alignment, they must be fixed to form an integral flow field structure. In addition to improving stability, it can effectively prevent misalignment caused by insecure connection between the two, which may affect the actual effect.

[0033] In this embodiment, the body 1 includes an anode plate 6 and a cathode plate 7. The anode plate 6 and the cathode plate 7 each have a plurality of ridge strips 4 and a number of groove strips 8. Adjacent ridge strips 4 are connected by groove strips 8. The groove strips 8 of the anode plate 6 are connected to the groove strips 8 of the cathode plate 7 in a one-to-one correspondence. The ridge strips 4 of the anode plate 6 and the ridge strips 4 of the cathode plate 7 are arranged back-to-back in a one-to-one correspondence.

[0034] The ridge strips 4 of the anode plate 6 and the ridge strips 4 of the cathode plate 7 respectively coincide with the first mesh strips 5 of the two metal mesh plates 3 in a one-to-one correspondence in a profiling or projection manner.

[0035] Specifically, a groove-like structure is formed between two adjacent ridge strips 4 and the groove strips 8 between the two ridge strips 4. The present invention aims to increase the depth of the groove-like structure.

[0036] That is, preferably, metal mesh plates 3 are respectively arranged on the two surfaces of the body 1. This method can ensure that the groove depth of the cathode plate 7 is basically the same as that of the anode plate 6, thereby ensuring the actual performance of the present invention.

[0037] In this embodiment, the metal mesh plate 3 is preferably fixedly connected to the cathode plate 7 because in practical applications, generally, the anode plate 6 requires a relatively shallow groove depth and the structure of the metal mesh plate 3 may not be necessary; while the cathode plate 7 requires a deeper groove depth, and adding the metal mesh plate 3 is beneficial to obtaining a deeper groove depth.

[0038] Specifically, as Figure 2 shown, as another embodiment of the present invention, the mesh plate is further provided with a plurality of second mesh strips 9. The second mesh strips 9 are arranged in parallel with the first mesh strips 5. The second mesh strips 9 are located between two adjacent ridge strips 4 and are spaced apart from the groove strips 8.

[0039] That is, in step B, the mesh strips include the first mesh strips 5 and the second mesh strips 9, and the second mesh strips 9 are located between two adjacent first mesh strips 5; after step C, the second mesh strips 9 are located between two adjacent ridge strips 4 of the body 1 and are spaced apart from the groove strips 8 of the body 1.

[0040] The total number of mesh bars of the mesh plate is larger than the number of ridge bars 4. Those connected to the ridge bars 4 become the first mesh bars 5, while those corresponding to the groove bars 8 are the second mesh bars 9. In fact, they can have the same shape. Through the arrangement of the second mesh bars 9, the width of the position where the groove faces the gas diffusion layer 2 is reduced, so as to disturb the gas flow passing through this position, that is, increase the gas flow inside the groove, thus avoiding the oxygen concentration at the position close to the gas diffusion layer 2 being lower than that at the bottom of the groove due to the participation of air in the reduction reaction near the gas diffusion layer 2, and further avoiding the reduction of the power output of the fuel cell caused by the above phenomenon.

[0041] Preferably, the mesh bars included in the metal mesh plate 3 are usually cross-shaped, that is, in addition to the first mesh bars 5 and the second mesh bars 9, the metal mesh plate 3 necessarily has third mesh bars (not shown in the figure) that cross the first mesh bars and the second mesh bars 9. There is a part of the third mesh bars located directly above the groove-shaped structure, and this part of the structure plays a blocking role for the gas: that is, when the gas flows in the groove-shaped structure and is blocked by the third mesh bars, the gas necessarily needs to change the flow direction, so as to collide with other gases, achieving a flow disturbance effect.

[0042] Through this flow disturbance, the gas flow near the gas diffusion layer 2 can be effectively made more frequent, so that the gas with reduced oxygen content due to the reaction with the gas diffusion layer 2 can flow faster, so as to ensure the oxygen-containing concentration around the gas diffusion layer 2, thus ensuring the power of the battery.

[0043] Specifically, the connection part of the ridge bar 4 and the groove bar 8 is an arc-shaped structure, that is, the above-mentioned corner position is a rounded corner. Compared with the etched forming body 1, the present invention focuses on using stamping forming with lower cost but forming a rounded corner structure. Cooperating with the metal mesh plate 3, a metal bipolar plate can be obtained at low cost, which is beneficial to promotion and use.

[0044] Furthermore, the ratio of the thickness of the body 1 to the thickness of the metal mesh plate 3 is greater than 2:1. Usually, the metal mesh plate 3 only plays the role of increasing the width, so the thickness of the metal mesh plate 3 should not exceed the thickness of the anode plate 6 and the cathode plate 7.

[0045] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention is disclosed above in a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, when making some changes or modifications using the above-disclosed technical content as equivalent change equivalent embodiments, but as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical means of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A metal bipolar plate for increasing groove depth, comprising a body and two gas diffusion layers respectively arranged at both ends of the body, characterized in that: A metal mesh plate is disposed between the body and at least one gas diffusion layer. The body is provided with a plurality of ridges, and the metal mesh plate is provided with a plurality of first mesh strips. The first mesh strips and the ridges are in one-to-one correspondence and projection coincidence to increase the groove depth between adjacent ridges.

2. The metal bipolar plate for increasing groove depth according to claim 1, wherein: The body and the metal mesh plate are fixedly connected by any one of the methods of bonding with conductive adhesive, soldering, laser welding, and resistance welding.

3. The metal bipolar plate for increasing groove depth according to claim 1, characterized in that: The body includes an anode plate and a cathode plate. The anode plate and the cathode plate respectively have a plurality of ridges and a plurality of groove strips. The adjacent ridges are connected by the groove strips. The groove strips of the anode plate and the groove strips of the cathode plate are connected in one-to-one correspondence. The ridges of the anode plate and the ridges of the cathode plate are arranged back to back in one-to-one correspondence. The ridges of the anode plate and the ridges of the cathode plate respectively coincide with the first mesh strips of the two metal mesh plates in one-to-one correspondence in profile or projection.

4. The metal bipolar plate for increasing groove depth according to claim 3, wherein: The mesh plate is further provided with a plurality of second mesh strips. The second mesh strips are arranged parallel to the first mesh strips. The second mesh strips are located between two adjacent ridges and are arranged at intervals with the groove strips.

5. The metal bipolar plate for increasing groove depth according to claim 3, wherein: The connection part of the ridge and the groove strip is an arc structure.

6. The metal bipolar plate for increasing groove depth according to claim 1, characterized in that: The number of the metal mesh plates is two, and the two metal mesh plates are respectively disposed on the upper surface and the lower surface of the body.

7. The metal bipolar plate for increasing the groove depth according to claim 3, characterized in that: The metal mesh plate is fixedly connected with the cathode plate.

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