Bipolar plate and application thereof, fuel cell stack and vehicle

Abstract

The bipolar plate comprises a cathode plate and an anode plate, the cathode plate is provided with a cooling flow field for guiding cooling liquid, the cooling flow field comprises a main cooling flow field area, the main cooling flow field area is provided with a plurality of cooling flow channels, the cooling flow channels are in a bent shape, and the flowing distances of the cooling liquid in the cooling flow channels are equal. According to the bipolar plate disclosed by the invention, the flow distances of the cooling liquid in the flow channels are equal in length through a forced guide mode, so that the pressure drop of each cooling flow channel is consistent, the flow uniformity is improved, the temperature of a reaction area of hydrogen and air is uniform, and the performance and reliability of electric pile power generation are improved. The invention also discloses a fuel cell stack, application of the bipolar plate in the fuel cell stack and a vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular, relates to a bipolar plate and application thereof, a fuel cell stack, and a vehicle. Background Art

[0002] The development and utilization of clean energy is an important means to solve the energy crisis and environmental pollution problems. The proton exchange membrane fuel cell is an environmentally friendly and efficient energy conversion device. It uses hydrogen and air to generate electricity under the action of a catalyst, and the only reaction product is water. Usually, hydrogen and air are transmitted through bipolar plates and chemically react at the three-phase interface of the membrane electrode. The bipolar plate plays the role of transporting gas, collecting current, conducting heat, and supporting structure, while the membrane electrode plays the role of catalytic reaction, conducting protons, etc., providing a place for the occurrence of chemical reactions. In order to improve the stability and durability of hydrogen fuel cells, the reaction of hydrogen and air requires a suitable temperature. The cooling methods of fuel cells mainly include air cooling and coolant cooling. Since the air cooling method is less efficient, coolant cooling is the preferred cooling method. This cooling method is to divide the bipolar plate into two monopolar plates, and set a cooling flow field between the monopolar plates to provide a flow channel for the coolant to control the temperature, discharge the heat generated in the chemical reaction, prevent the battery temperature from being too high, and make the temperature distribution uniform when the reaction occurs, thereby improving the reaction efficiency and increasing the durability and service life of the fuel cell.

[0003] In the prior art, the cooling flow field of the bipolar plate is mainly parallel flow channels, serpentine flow channels and bionic flow channels. These forms of cooling flow fields have different characteristics in terms of inlet and outlet temperature difference, temperature uniformity and pressure drop loss. The parallel flow field is composed of several parallel flow channels arranged in a specific direction. This design does not consider the influence of different flow channel structures and is prone to cause local flow dead zones, which in turn leads to local overheating of the flow field. The serpentine flow channel cooling flow field can increase the flow rate of the coolant and enhance the heat exchange effect to improve the cooling effect, but the pressure drop is higher than that of the parallel flow channel cooling flow field, and the requirements for the external drive coolant circulation device are higher, and the parasitic loss of the system increases. The bionic flow channel cooling flow field is based on the plant veins and animal heart and lung structures. The cooling flow channel based on the bionic structure is designed through the principle of bionic similarity. The cooling performance of the bionic flow channel is not only better than that of the serpentine cooling flow channel, but also has a lower pressure drop than that of the parallel cooling flow channel. It is a cooling flow channel with good comprehensive performance, but the processing and manufacturing of the bionic flow channel is relatively complicated and the cost is high, which is not conducive to industrial production and testing.

[0004] The Chinese patent application number 201210129676.1 discloses a bipolar plate, a cooling plate and a fuel cell stack: a coolant flow field is provided on one side of the bipolar plate, and the coolant flow field includes: a coolant inlet channel and a coolant outlet channel. The coolant flow field is composed of a plurality of spaced flow channel grooves and flow channel ridges extending in parallel between the coolant inlet channel and the coolant outlet channel. The cross-sectional area and / or perimeter of the flow channel groove located in the middle of the plurality of flow channel grooves is the largest, and the cross-sectional area and / or perimeter of the flow channel groove gradually decreases in the direction toward both sides. The invention can effectively solve the problem of temperature difference between the center and the edge of a single fuel cell under certain working conditions, but due to the characteristics of the parallel flow channels and the large number of parallel flow channels, local flow dead zones are very likely to occur under variable load conditions, and the heat generated by the reaction cannot be effectively extracted, affecting durability and service life.

[0005] The Chinese patent application number 202410305991.8 discloses a bionic structure flow field of a fuel cell bipolar plate: the flow field inlet is arranged at the center of one side of the bipolar plate body; the main inlet flow channel is arranged on the bipolar plate body and arranged along the center line of the bipolar plate body, one end of the main inlet flow channel is connected to the flow field inlet, and multiple N-level (N≥2, N is an integer) branch inlet flow channels are symmetrically arranged on both sides of the main inlet flow channel, and multiple branch inlet flow channels of the next level are arranged along the length direction of the branch inlet flow channel of the previous level, and one end of each branch inlet flow channel of the next level is connected to the branch inlet flow channel of the previous level. The invention has multiple N-level structures along the center line of the bipolar plate body. On the one hand, the structure is relatively complex and costly to manufacture, and on the other hand, it is also difficult to detect, which is not conducive to engineering and batch use.

[0006] It is desirable to provide an improved bipolar plate, particularly with regard to how to improve the uniformity of coolant flow and enhance the performance and reliability of the fuel cell stack. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a bipolar plate, the purpose of which is to improve the uniformity of coolant flow.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a bipolar plate, including a cathode plate and an anode plate, a cooling flow field for guiding the coolant is arranged on the cathode plate, the cooling flow field includes a main cooling flow field area, and a plurality of cooling channels are arranged in the main cooling flow field area. The cooling channels are bent in shape, and the flow distance of the coolant in each cooling channel is of equal length.

[0009] The cooling flow field also includes a cooling flow field inlet manifold and a coolant inflow guide area. The cooling flow field inlet manifold is connected to the coolant inflow guide area, and the coolant inflow guide area is connected to the cooling flow channel set in the main cooling flow field area.

[0010] A plurality of coolant inflow guide areas are provided.

[0011] The cooling flow field also includes a coolant outflow guide area and a cooling flow field outlet manifold. The cooling flow field outlet manifold is connected to the coolant outflow guide area, and the coolant outflow guide area is connected to the cooling flow channel arranged in the main cooling flow field area.

[0012] A plurality of coolant outflow guide areas are provided.

[0013] The number of cooling channels is 25.

[0014] The cooling channel has a uniform cross-section.

[0015] The present invention also provides a fuel cell stack, comprising the bipolar plate.

[0016] The present invention also provides an application of the bipolar plate in a fuel cell stack.

[0017] The present invention also provides a vehicle, comprising the fuel cell stack.

[0018] The bipolar plate of the present invention, through forced guidance, makes the flow distance of the coolant in the flow channel equal, so that the pressure drop of each cooling flow channel is consistent, the flow uniformity is improved, so that the temperature of the reaction zone of hydrogen and air is uniform, and the performance and reliability of the power generation of the fuel cell stack are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the position of the cooling flow field in the bipolar plate;

[0020] Figure 2 It is a schematic diagram of the cooling flow field structure;

[0021] Figure 3 is a schematic diagram of coolant flow;

[0022] Figure 4 is the flow uniformity diagram of the cooling flow field;

[0023] The markings in the above figures are: 1, bipolar plate; 11, cathode plate; 12, anode plate; 112, main cooling flow field area; 111, cooling flow field inlet manifold; 113, cooling flow field outlet manifold; 1121, coolant inflow guide area; 1122, coolant flow route in the flow field area; 1123, coolant outflow guide area. DETAILED DESCRIPTION

[0024] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] like Figures 1 to 3 As shown, the present invention provides a bipolar plate, including a cathode plate 11 and an anode plate 12, wherein a cooling flow field for guiding a coolant is arranged on the cathode plate 11, and the cooling flow field includes a main cooling flow field area 112, wherein the main cooling flow field area 112 is provided with a plurality of cooling channels, the cooling channels are in a bent shape, and the flow distance of the coolant in each cooling channel is of equal length.

[0027] The cooling flow field further includes a cooling flow field inlet manifold 111 and a coolant inflow guide area 1121 . The cooling flow field inlet manifold 111 is connected to the coolant inflow guide area 1121 . The coolant inflow guide area 1121 is connected to the cooling flow channel provided in the main cooling flow field area 112 .

[0028] A plurality of coolant inflow guide areas 1121 are provided.

[0029] The cooling flow field further includes a coolant outflow guide area 1123 and a cooling flow field outlet manifold 113 . The cooling flow field outlet manifold 113 is connected to the coolant outflow guide area 1123 . The coolant outflow guide area 1123 is connected to the cooling flow channel provided in the main cooling flow field area 112 .

[0030] A plurality of coolant outflow guide areas 1123 are provided.

[0031] The number of cooling channels is 25.

[0032] The cooling channel has a uniform cross-section.

[0033] The present invention also provides a fuel cell stack, comprising the bipolar plate.

[0034] The present invention also provides an application of the bipolar plate in a fuel cell stack.

[0035] The present invention also provides a vehicle, comprising the fuel cell stack.

[0036] Example

[0037] First, as Figures 1 to 3 As shown, an embodiment of the present invention provides a bipolar plate, including a cathode plate 11 and an anode plate 12. A cooling flow field for guiding the coolant is arranged on the cathode plate 11. The cooling flow field includes a main cooling flow field area 112. The main cooling flow field area 112 is provided with a plurality of cooling channels. The cooling channels are bent in shape, and the flow distance of the coolant in each cooling channel is of equal length.

[0038] Specifically, in the prior art, the parallel flow field is composed of parallel flow channels arranged along a specific direction. This design does not take into account the influence of different flow channel structures and is prone to cause local flow dead zones, which in turn leads to local overheating of the flow field; the pressure drop of the serpentine flow channel cooling flow field is higher than that of the parallel flow channel cooling flow field, and the requirements for the external device driving the coolant circulation are higher, and the parasitic loss of the system is increased; the processing and manufacturing of the bionic flow channel is relatively complex and costly, which is not conducive to industrial production and testing.

[0039] In an embodiment of the present invention, a forced guided graphite bipolar plate cooling flow field is provided. The cooling flow field is arranged on the cathode plate 11. When the cathode plate 11 and the anode plate 12 are sealed to form the bipolar plate 1, a closed cooling flow field is formed between the two plates, which is used for cooling the fuel cell during power generation and providing a suitable temperature required for the reaction.

[0040] like Figures 1 to 3 As shown, in an embodiment of the present invention, the cooling flow field also includes a cooling flow field inlet manifold 111 and a coolant inlet guide area 1121. The cooling flow field inlet manifold 111 is connected to the coolant inlet guide area 1121, and the coolant inlet guide area 1121 is connected to the cooling flow channel set in the main cooling flow field area 112.

[0041] like Figures 1 to 3 As shown, in the embodiment of the present invention, a plurality of coolant inlet guide areas 1121 are provided, and one cooling flow field inlet manifold 111 is provided, and the cooling flow field inlet manifold 111 is connected to all the coolant inlet guide areas 1121 .

[0042] like Figures 1 to 3 As shown, in an embodiment of the present invention, the cooling flow field also includes a cooling liquid outflow guide area 1123 and a cooling flow field outlet manifold 113, the cooling flow field outlet manifold 113 is connected to the cooling liquid outflow guide area 1123, the cooling liquid outflow guide area 1123 is connected to the cooling flow channel set in the main cooling flow field area 112, and the cooling flow field outlet manifold 113 and the cooling flow field inlet manifold 111 are respectively located at the two ends of the cathode plate 11.

[0043] like Figures 1 to 3As shown, in the embodiment of the present invention, a plurality of coolant outflow guide areas 1123 are provided, and one cooling flow field outlet manifold 113 is provided, and the cooling flow field outlet manifold 113 is connected to all the coolant outflow guide areas 1123 .

[0044] like Figures 1 to 3 As shown, in the embodiment of the present invention, 25 cooling channels are provided. The cooling channels are bent in shape, and are specifically composed of a plurality of straight channels connected in sequence, and two adjacent straight channels are perpendicular to each other. The bent cooling channels can increase the flow path length of the coolant in the channels, thereby extending the contact time between the coolant and the surrounding heat source.

[0045] In the embodiment of the present invention, the entire cooling flow field is composed of a cooling flow field inlet manifold 111, a coolant inflow guide area 1121, a main cooling flow field area 112, a coolant outflow guide area 1123, and a cooling flow field outlet manifold 113. The basic form of the flow field is a double-channel serpentine flow field form. Through the forced guidance form, the coolant enters the coolant inflow guide area 1121 from the cooling flow field inlet manifold 111, and enters the main cooling flow field area 112 after distribution. The coolant inflow guide area 1121 can ensure that the coolant is evenly distributed to each cooling channel of the main cooling flow field area 112, avoiding congestion and uneven distribution of the coolant at the inlet, thereby improving the cooling efficiency. The main cooling flow field area 112 has a total of 25 cooling channels, and each cooling channel has the same length after bending, so that the flow distance of the coolant in the cooling channel is equal, so that the pressure drop of each cooling channel is consistent, reducing the flow unevenness caused by the pressure drop difference, and improving the flow uniformity. Since the flow distance and pressure drop of each cooling channel are consistent, the flow of the coolant is more uniform, thereby improving the uniformity of the temperature in the reaction zone between hydrogen and air, and thus improving the performance and reliability of the fuel cell stack power generation.

[0046] In order to reduce the impact of the cooling channel bend on the channel resistance and taking into account the strength of the channel structure, a ridge along the coolant flow direction is set between two adjacent cooling channels to improve the strength of the cooling flow field without affecting the channel resistance, thus forming a dual-channel structure. The ridge serves as an additional structural support to increase the overall strength and rigidity of the cooling channel, especially in stress concentration areas such as bends. This helps prevent channel deformation or rupture caused by coolant pressure or external loads, and improves the reliability and durability of the system.

[0047] The dual-channel structure can reduce the flow resistance of the coolant in the flow channel, allowing the coolant to flow more smoothly along the predetermined path, reducing unnecessary energy loss, and reducing the demand for external auxiliary components of the system for cooling, thereby increasing the power density of the fuel cell and improving the overall performance of the fuel cell.

[0048] After the coolant absorbs a certain amount of heat through heat conduction, it flows from the main cooling flow field area 112 to the coolant outflow guide area 1123, and finally flows out of the bipolar plate 1 through the cooling flow field outlet manifold 113. The coolant is cooled by an external cooling device and pumped into the bipolar plate 1 again, completing a heat exchange cycle.

[0049] like Figures 1 to 3 As shown, in the embodiment of the present invention, the cooling channel has a uniform cross-sectional shape, which has the advantages of simple processing and manufacturing, convenient quality inspection, and is conducive to engineering applications.

[0050] The bipolar plate of the above structure has a dual-channel serpentine flow field as the basic form of the cooling flow field. Through forced guidance, the flow distance of the coolant in the flow channel is equal, so that the pressure drop of each cooling flow channel is consistent, the flow uniformity is improved, and the temperature of the reaction zone of hydrogen and air is uniform, which improves the performance and reliability of the power generation of the fuel cell stack. The dual-channel structure can reduce the flow resistance of the coolant in the flow channel and reduce the demand for external auxiliary parts of the system for cooling, thereby improving the power density of the fuel cell. In addition, the flow channels in this cooling flow field are of equal cross-sectional shape, which has the advantages of simple processing and manufacturing, convenient quality inspection, and is conducive to engineering application. The bipolar plate cooling flow field obtained in the above manner has the characteristics of low flow resistance, uniform flow, simplicity and reliability, and can efficiently provide cooling for the fuel cell and improve the performance and reliability of the fuel cell stack.

[0051] In a second aspect, an embodiment of the present invention provides a fuel cell stack, including a bipolar plate of the above structure. The specific structure of the bipolar plate can be referred to Figures 1 to 4 Since the fuel cell stack of the present invention includes the bipolar plate in the above embodiment, it has all the advantages of the above bipolar plate.

[0052] In a third aspect, an embodiment of the present invention provides an application of a bipolar plate in a fuel cell stack.

[0053] In a fourth aspect, an embodiment of the present invention provides a vehicle, comprising a fuel cell stack of the above structure, wherein the fuel cell stack comprises a bipolar plate of the above structure. The specific structure of the bipolar plate can be referred to Figures 1 to 4 Since the vehicle of the present invention includes the bipolar plate in the above embodiment, it has all the advantages of the above bipolar plate.

[0054] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A bipolar plate, comprising a cathode plate and an anode plate, characterized in that: The cathode plate is provided with a cooling flow field for guiding the cooling liquid, the cooling flow field includes a main cooling flow field area, the main cooling flow field area is provided with a plurality of cooling channels, the cooling channels are in a bent shape, and the flow distance of the cooling liquid in each cooling channel is of equal length.

2. The bipolar plate according to claim 1, comprising a cathode plate and an anode plate, characterized in that: The cooling flow field also includes a cooling flow field inlet manifold and a coolant inflow guide area. The cooling flow field inlet manifold is connected to the coolant inflow guide area, and the coolant inflow guide area is connected to the cooling flow channel set in the main cooling flow field area.

3. The bipolar plate according to claim 2, comprising a cathode plate and an anode plate, characterized in that: A plurality of coolant inflow guide areas are provided.

4. The bipolar plate according to claim 2, comprising a cathode plate and an anode plate, characterized in that: The cooling flow field also includes a coolant outflow guide area and a cooling flow field outlet manifold. The cooling flow field outlet manifold is connected to the coolant outflow guide area, and the coolant outflow guide area is connected to the cooling flow channel arranged in the main cooling flow field area.

5. The bipolar plate according to claim 4, comprising a cathode plate and an anode plate, characterized in that: A plurality of coolant outflow guide areas are provided.

6. The bipolar plate according to any one of claims 1 to 5, comprising a cathode plate and an anode plate, characterized in that: The number of cooling channels is 25.

7. The bipolar plate according to any one of claims 1 to 5, comprising a cathode plate and an anode plate, characterized in that: The cooling channel has a uniform cross-section.

8. A fuel cell stack, characterized in that: Comprising the bipolar plate according to any one of claims 1 to 7.

9. Use of the bipolar plate according to any one of claims 1 to 7 in a fuel cell stack.

10. A vehicle, characterized in that: Comprising the fuel cell stack as described in claim 8.

Images