Bipolar plate and fuel cell and electrolysis device thereof

Abstract

The bipolar plate comprises a plate body, the plate body comprises a first inlet and a first outlet which are distributed at intervals in the first direction of the plate body, and a second inlet and a second outlet which are distributed at intervals in the second direction of the plate body; wherein the second direction is perpendicular to the first direction, a plurality of first flow channels which are distributed in the second direction at intervals and serve as reaction areas are arranged on one surface of the plate body, and the inlet end of each first flow channel is directly communicated with the first inlet and is distributed in a right corresponding mode. The outlet end of the first air inlet is directly communicated with the first outlet and is correspondingly distributed with the first outlet; according to the utility model, the design of the flow field is optimized, the key defects in the prior art are overcome, and the performance and the applicability of the fuel cell are obviously improved.

Description

Technical Field

[0001] This utility model belongs to the field of fuel cells, specifically relating to a bipolar plate. This utility model also relates to fuel cells and electrolysis devices using the bipolar plate. Background Technology

[0002] A fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy; it is also known as an electrochemical generator. Because fuel cells convert the Gibbs free energy portion of the fuel's chemical energy into electrical energy through an electrochemical reaction, they are not limited by the Carnot cycle effect and have a high energy conversion rate. Furthermore, fuel cells using hydrogen as fuel produce water as a reaction product, making them environmentally friendly and theoretically capable of zero emissions. In addition, fuel cells have no mechanical transmission parts, few moving parts, and very low noise during operation. Moreover, fuel cells also have advantages such as high specific energy, high reliability, wide fuel range, short start-up time, and small size.

[0003] Its small size and portability make it a promising power generation technology, demonstrating its advantages in energy conservation and environmental protection.

[0004] Structurally, a fuel cell typically consists of a membrane electrode assembly (MEA) and a current collector. The MEA is the site of the electrochemical reactions where the reducing agent (usually methanol or hydrogen) undergoes oxidation and the oxidant (usually oxygen or air) undergoes reduction. A traditional MEA mainly comprises a proton exchange membrane (PEM) with a cathode and anode integrally mounted on either side, and gas diffusion layers (GDL) located on the upper and lower surfaces of the PEM. To promote the electrochemical reactions, a catalyst (usually located at the interface between the PEM and the GDL) is typically placed between the cathode, anode, and PEM. The current collector, often called a bipolar plate, distributes fuel and air to the anode and cathode surfaces and dissipates heat from the stack. It is also a key component connecting individual cells in series to form the fuel cell stack, primarily separating the oxidant, reducing agent, and coolant, and collecting current.

[0005] Since the flow field of a bipolar plate directly determines the uniformity of fluid distribution, parasitic power loss, and the smoothness of the transport of reaction products, the flow field design of a bipolar plate is a key factor in determining the core performance of the plate.

[0006] In existing typical bipolar plate flow field designs for fuel cells, the inlet and outlet positions of the reductant, oxidant, and coolant are usually located along the same length or width of the plate. This layout leads to coupling between the inlet and outlet positions and the reaction zone flow channel, which not only increases the design complexity but also requires a distribution zone (also known as a "transition zone") to distribute the fluid from the narrower manifold channel to the wider reaction zone channel, since all three chambers (reductant, oxidant, and coolant) need to introduce fluid into the reaction zone. This distribution transition structure increases the pressure drop in the fluid flow, resulting in greater parasitic power losses. Furthermore, the fluid states in the distribution zone and the reaction zone differ significantly. The uneven reaction in this region leads to a decline in overall reaction performance. This uneven reaction not only affects the efficiency of the battery but may also shorten its lifespan. At the same time, in order to achieve uniform fluid distribution and timely removal of reaction products, a relatively complex distribution zone flow channel needs to be designed, which further increases the complexity of flow field design and processing and poses a challenge to low-cost production. In addition, since the fluid channels in the distribution zone are usually irregularly shaped, if the membrane electrode assembly (MEA) needs to be matched with it, the carbon paper, frame, and CCM (catalyst coating membrane) of the MEA all need to be designed with irregular shapes. This not only increases the cost of the MEA but also significantly increases the processing difficulty.

[0007] Therefore, the applicant seeks technical solutions to address the above-mentioned technical problems. Summary of the Invention

[0008] In view of this, the purpose of this utility model is to propose a bipolar plate and its fuel cell and electrolysis device, which optimizes the flow field design, overcomes the key defects in the prior art, and significantly improves the performance and applicability of the fuel cell.

[0009] After exploration, the applicant discovered that the main cause of significant pressure drop in the existing bipolar plate structure of fuel cells lies in the distribution area of ​​the oxidant chamber (in low-temperature fuel cells, the oxidant is usually air), which leads to a significant amount of parasitic power loss.

[0010] Therefore, the technical solution adopted by this utility model is as follows:

[0011] A bipolar plate includes a plate body, the plate body including a first inlet and a first outlet spaced apart in a first direction, and a second inlet and a second outlet spaced apart in a second direction; wherein the second direction is perpendicular to the first direction, and a plurality of first channels spaced apart in the second direction and serving as reaction zones are provided on one surface of the plate body, the inlet end of each first channel being directly connected to the first inlet and being positively corresponding to it, and the outlet end being directly connected to the first outlet and being positively corresponding to it.

[0012] Preferably, the first inlet extends from its first end to its second end in a second direction of the plate, and the distance between its first end and its second end is equal to or substantially equal to the distance between the inlet end of the first flow channel located at the first end in the second direction and the inlet end of the first flow channel located at the second end in the second direction; and / or the first outlet extends from its first end to its second end in a second direction of the plate, and the distance between its first end and its second end is equal to or substantially equal to the distance between the outlet end of the first flow channel located at the first end in the second direction and the outlet end of the first flow channel located at the second end in the second direction.

[0013] Preferably, the first inlet and the first outlet are symmetrically distributed with respect to the center line of the plate in a first direction; the second inlet and the second outlet are symmetrically or asymmetrically distributed with respect to the center line of the plate in a second direction.

[0014] Preferably, the first inlet is an oxidant inlet; each first flow channel is straight; the second inlet is a reducing agent inlet; and / or the first direction is the length direction, width direction, or side length direction of the plate.

[0015] Preferably, in order to further achieve the straight-through effect of the second flow channel (usually as a reducing agent flow channel) and reduce pressure drop loss, the other surface of the plate is provided with a second flow channel as a reaction zone. The inlet end of the second flow channel is directly connected to the second inlet and is distributed in a positive correspondence, and its outlet end is directly connected to the second outlet and is distributed in a positive correspondence.

[0016] Preferably, in order to achieve a good cooling and heat dissipation effect, the plate further includes a coolant inlet and a coolant outlet, which are spaced apart in the second direction of the plate; wherein, the second inlet and the second outlet are asymmetrically distributed with respect to the center line of the second direction of the plate, and the coolant inlet and the coolant outlet are asymmetrically distributed with respect to the center line of the second direction of the plate.

[0017] Preferably, the second flow channel includes a second flow channel inlet guide section that is directly connected to and correspondingly distributed with the second inlet, and a second flow channel outlet confluence section that is directly connected to and correspondingly distributed with the second outlet. The second flow channel inlet guide section and the second flow channel outlet confluence section are connected through a middle section of the second flow channel. The fluid direction of the second flow channel inlet guide section and the second flow channel outlet confluence section is the same and perpendicular to the fluid direction of the middle section of the second flow channel. Preferably, the fluid direction of the middle section of the second flow channel is the same as the fluid direction of the first flow channel.

[0018] Preferably, the plate body includes at least a first plate body unit and a second plate body unit stacked together, wherein,

[0019] Each plate unit is equipped with a first inlet, a first outlet, a second inlet, a second outlet, a coolant inlet, and a coolant outlet;

[0020] The outer surface of the first plate unit is provided with the first flow channel, and the outer surface of the second plate unit is provided with the second flow channel;

[0021] Meanwhile, a coolant flow channel is formed between the first plate unit and the second plate unit, which is connected to the coolant inlet and coolant outlet respectively.

[0022] Preferably, the plate is a silicon electrode plate, a graphite electrode plate, a metal electrode plate, a ceramic electrode plate, or a composite material electrode plate.

[0023] Preferably, a fuel cell includes a bipolar plate; wherein the bipolar plate is a bipolar plate according to the above description.

[0024] Preferably, an electrolysis apparatus includes a bipolar plate; wherein the bipolar plate is a bipolar plate according to the above description.

[0025] It should be noted that the term "basically equal to" in this application means that the distances described by the two are close, and the distance described by the former is approximately greater than the distance described by the latter, but the distance difference does not exceed 20%, preferably not more than 10%.

[0026] For fuel cells, this invention proposes to set the oxidant inlet and outlet and the reductant inlet and outlet inlet in different directions of the electrode plate. Specifically, the inlet end of each first flow channel (preferably as the oxidant flow channel) is directly connected to the first inlet and is distributed in a positive correspondence, and its outlet end is directly connected to the first outlet and is distributed in a positive correspondence. Only the specific property requirements of the oxidant and reductant need to be considered, without worrying about the coupling effect between the two, which simplifies the flow field layout and improves the design flexibility and adjustability. At the same time, there is no need to set up a distribution area or transition area, which greatly reduces the pressure drop of the oxidant path (in actual implementation applications, this design can reduce the fluid pressure drop by up to about 20%), significantly reduces parasitic power loss, and thus expands the applicability of the fuel cell BOP (Balance of Plant, battery pack peripheral equipment). It can not only use traditional air compressors and blowers, but also other types of gas supply equipment.

[0027] It should also be noted that since using the first flow channel as the oxidant flow channel can significantly reduce problems such as parasitic power loss in fuel cells, in specific implementation, the second flow channel and coolant flow channel in this application can adopt the preferred scheme proposed in this application, or conventional flow channel schemes can also be adopted, all of which are within the scope of protection of this application.

[0028] Because the first flow channel of this application adopts a straight-through design, directly connecting with the inlet and outlet, its structure is very simple and completely uniform, effectively ensuring the uniform distribution of fluid in the reaction zone, while also ensuring the rapid removal of reactants, further improving the reaction efficiency and overall performance of the fuel cell. In addition, since the first flow channel proposed in this application no longer requires a special distribution zone or transition zone, it not only expands the effective utilization rate of the electrode plates, but also maximizes the matching with the production characteristics of the membrane electrode roll, providing a basis for cost optimization of bipolar plates and membrane electrodes, further reducing the production cost of fuel cells and enhancing market competitiveness.

[0029] It should be noted that those skilled in the art can apply the bipolar plate provided in this application as a bipolar plate in an electrolysis device according to actual needs. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the bipolar plate in Embodiment 1 of this application (showing the surface of the bipolar plate with a first flow channel, and the arrows in the figure represent the flow direction of the oxidant).

[0031] Figure 2 This is a schematic diagram of the bipolar plate in Embodiment 2 of this application (showing the surface of the bipolar plate with a first flow channel, and the arrows in the figure represent the flow direction of the oxidant).

[0032] Figure 3 This is a schematic diagram of the bipolar plate in Embodiment 3 of this application (showing the surface of the bipolar plate with a first flow channel, and the arrows in the figure represent the flow direction of the oxidant).

[0033] Figure 4 This is a schematic diagram of the bipolar plate in Embodiment 4 of this application (showing the surface of the bipolar plate with a first flow channel).

[0034] Figure 5 This is a schematic diagram of the bipolar plate in Embodiment 4 of this application (showing the surface of the bipolar plate with a second flow channel). Detailed Implementation

[0035] This utility model discloses a bipolar plate, including a plate body, the plate body including a first inlet and a first outlet spaced apart in a first direction, and a second inlet and a second outlet spaced apart in a second direction; wherein, the second direction is perpendicular to the first direction, and a plurality of first channels spaced apart in the second direction and serving as reaction zones are provided on one surface of the plate body, the inlet end of each first channel being directly connected to the first inlet and being positively corresponding, and the outlet end being directly connected to the first outlet and being positively corresponding.

[0036] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Example 1: Please refer to Figure 1 As shown, a bipolar plate includes a plate body 10. The plate body 10 includes a first inlet 11 (used to transport an oxidant, specifically air is used as the oxidant in this embodiment, but other known oxidants can be used in other embodiments) and a first outlet 12, and a second inlet 13 (used to transport a reducing agent, specifically hydrogen is used as the reducing agent in this embodiment, but other known reducing agents can be used in other embodiments) and a second outlet 14, which are respectively distributed at intervals in a second direction. The second direction is perpendicular to the first direction. A surface of the plate body 10 is provided with a plurality of first channels (not shown in the figure) that are distributed at intervals in the second direction and serve as reaction zones. The inlet end of each first channel is directly connected to the first inlet 11 and is distributed in a positive correspondence, and its outlet end is directly connected to the first outlet 12 and is distributed in a positive correspondence.

[0038] Specifically, in this embodiment, each first flow channel is in a straight line shape; the plate 10 is specifically a silicon electrode plate, which is square in shape, and the first direction is the side length direction of the plate 10; in other embodiments, graphite electrode plates, metal electrode plates, ceramic electrode plates, or composite material electrode plates can also be used, and other shapes of plates can also be used. This application does not impose a unique limitation on its implementation.

[0039] Preferably, in this embodiment, the first inlet 11 extends from its first end 10a to its second end 10b in the second direction of the plate 10, and the distance between its first end 10a and its second end 10b is equal to (or slightly greater than in other embodiments, with the difference ratio preferably not exceeding 15%, more preferably not exceeding 10%) the distance between the inlet end of the first flow channel located at the first end in the second direction and the inlet end of the first flow channel located at the second end in the second direction; the first inlet 11 and the first outlet 12 are symmetrically distributed with respect to the center line of the first direction of the plate 10; the second inlet 13 and the second outlet 14 are asymmetrically distributed with respect to the center line of the second direction of the plate 10.

[0040] Preferably, in this embodiment, the other surface of the plate 10 is provided with a second flow channel (not shown in the figure) serving as a reaction zone. The inlet end of the second flow channel is directly connected to the second inlet 13 and is distributed in a positive correspondence, and its outlet end is directly connected to the second outlet 14 and is distributed in a positive correspondence. The second flow channel is in a bent shape. The specific design of the second flow channel can be found in the relevant content of Embodiment 4.

[0041] Example 2: The remaining technical solutions of Example 2 are the same as those of Example 1, except that: Please refer to... Figure 2 As shown, this embodiment 2 provides a bipolar plate, including a plate body 20, a second inlet 23 and a second outlet 24 which are symmetrically distributed with respect to the second direction centerline of the plate body 20, a second flow channel which is straight and the flow direction of the second flow channel is perpendicular to the flow direction of the first flow channel.

[0042] Example 3: The remaining technical solutions of Example 3 are the same as those of Example 1, except that: Please refer to... Figure 3 As shown, this embodiment 2 provides a bipolar plate, including a plate body 30. The plate body 30 also includes a coolant inlet 35 and a coolant outlet 36, which are spaced apart in the second direction of the plate body 30. The second inlet 33 and the second outlet 34 are asymmetrically distributed with respect to the center line of the second direction of the plate body 30, and the coolant inlet 35 and the coolant outlet 36 are asymmetrically distributed with respect to the center line of the second direction of the plate body 30. The specific design of the second flow channel and the coolant flow channel can be found in the relevant content of embodiment 4.

[0043] Example 4: The remaining technical solutions of Example 4 are the same as those of Example 1, except that: please refer to... Figure 4 and Figure 5 As shown, the plate 40 is specifically a silicon electrode plate, which is rectangular in shape. The first direction is the width direction of the plate 40, and the second direction is the length direction of the plate 40. The plate 40 also includes a coolant inlet 45 and a coolant outlet 46, which are spaced apart in the second direction of the plate 40. The second inlet 43 and the second outlet 44 are asymmetrically distributed with respect to the center line of the second direction of the plate 40, and the coolant inlet 45 and the coolant outlet 46 are asymmetrically distributed with respect to the center line of the second direction of the plate 40.

[0044] Preferably, in this embodiment, the plate 40 includes a first plate unit and a second plate unit stacked together, wherein each plate unit is provided with a first inlet 41, a first outlet 42, a second inlet 43, a second outlet 44, a coolant inlet 45, and a coolant outlet 46; the outer surface of the first plate unit is provided with a first flow channel 47, and the outer surface of the second plate unit is provided with a second flow channel 48; at the same time, a coolant flow channel (not shown) is formed between the first plate unit and the second plate unit, which is connected to the coolant inlet and the coolant outlet respectively; the first flow channel 47 is in a straight line shape;

[0045] More preferably, in this embodiment, the second flow channel 48 includes a second flow channel inlet guide section 48a that is directly connected to and correspondingly distributed with the second inlet 43, and a second flow channel outlet confluence section 48b that is directly connected to and correspondingly distributed with the second outlet 44. The second flow channel inlet guide section 48a and the second flow channel outlet confluence section 48b are connected through a second flow channel intermediate section 48c. The fluid direction of the second flow channel inlet guide section 48a and the second flow channel outlet confluence section 48b is the same and perpendicular to the fluid direction of the second flow channel intermediate section 48c. The fluid direction of the second flow channel intermediate section 48c is the same as the fluid direction of the first flow channel 47.

[0046] Example 5: A fuel cell, including a bipolar plate; wherein the bipolar plate adopts any of the bipolar plates described in Examples 1-4; preferably, the specific application implementation scheme of the fuel cell can be found in the applicant's prior application 201810577211.X.

[0047] Example 6: An electrolysis device, including a bipolar plate; wherein the bipolar plate is any of the bipolar plates described in Examples 1-4; preferably, the specific application implementation scheme of the electrolysis device can be found in the applicant's prior application 2023110128956.

[0048] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bipolar plate comprising a plate body, characterized in that The plate body comprises first inlets and first outlets spaced apart in a first direction thereof, and second inlets and second outlets spaced apart in a second direction thereof; wherein the second direction is perpendicular to the first direction, and one surface of the plate body is provided with a plurality of first flow channels as reaction zones and spaced apart in the second direction, and the inlet end of each first flow channel is in direct communication with and in positive correspondence with the first inlet, and the outlet end of each first flow channel is in direct communication with and in positive correspondence with the first outlet.

2. The bipolar plate of claim 1, wherein The first inlet extends from a first end to a second end in the second direction of the plate body, and the distance between the first end and the second end is equal to or substantially equal to the distance between the inlet end of the first flow channel at the first end in the second direction and the inlet end of the first flow channel at the second end in the second direction; and / or the first outlet extends from a first end to a second end in the second direction of the plate body, and the distance between the first end and the second end is equal to or substantially equal to the distance between the outlet end of the first flow channel at the first end in the second direction and the outlet end of the first flow channel at the second end in the second direction.

3. The bipolar plate of claim 1, wherein The first inlet and the first outlet are symmetrically distributed with respect to the center line of the plate body in the first direction; and the second inlet and the second outlet are symmetrically or asymmetrically distributed with respect to the center line of the plate body in the second direction.

4. The bipolar plate of claim 1, wherein The first inlet is an oxidant inlet; each first flow channel has a linear shape; the second inlet is a reducing agent inlet; and / or the first direction is the length direction, the width direction or the side length direction of the plate body.

5. The bipolar plate of claim 1, wherein The other surface of the plate body is provided with second flow channels as reaction zones, and the inlet end of each second flow channel is in direct communication with and in positive correspondence with the second inlet, and the outlet end of each second flow channel is in direct communication with and in positive correspondence with the second outlet.

6. The bipolar plate of claim 5, wherein The plate body further comprises a coolant inlet and a coolant outlet, and the coolant inlet and the coolant outlet are spaced apart in the second direction of the plate body; wherein the second inlet and the second outlet are asymmetrically distributed with respect to the center line of the plate body in the second direction, and the coolant inlet and the coolant outlet are asymmetrically distributed with respect to the center line of the plate body in the second direction.

7. The bipolar plate of claim 6, wherein The second flow channel comprises a second flow channel inlet guide section in direct communication with and in positive correspondence with the second inlet, and a second flow channel outlet converging section in direct communication with and in positive correspondence with the second outlet, and the second flow channel inlet guide section and the second flow channel outlet converging section are in communication through a second flow channel intermediate section; wherein the fluid direction of the second flow channel inlet guide section and the second flow channel outlet converging section is the same, and perpendicular to the fluid direction of the second flow channel intermediate section.

8. The bipolar plate of claim 7, wherein The fluid direction of the second flow channel intermediate section is the same as the fluid direction of the first flow channel.

9. Bipolar plate according to one of claims 1-8, characterized in that The plate body comprises at least a first plate body unit and a second plate body unit stacked together, Each plate body unit is provided with a first inlet, a first outlet, a second inlet, a second outlet, a coolant inlet and a coolant outlet; The outer surface of the first plate body unit is provided with the first flow channels, and the outer surface of the second plate body unit is provided with the second flow channels; and The first plate body unit and the second plate body unit are connected by a plurality of connecting channels. Meanwhile, a coolant flow channel is formed between the first plate unit and the second plate unit, and is communicated with the coolant inlet and the coolant outlet respectively.

10. The bipolar plate of claim 1, wherein The plate body is a silicon plate, a graphite plate, a metal plate, a ceramic plate or a composite material plate.

11. A fuel cell comprising a bipolar plate; characterized by, The bipolar plate is according to any one of claims 1-10.

12. An electrolytic device comprising a bipolar plate; characterized by, The bipolar plate is according to any one of claims 1-3 or any one of claims 5-10.

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