Fuel cell cathode flow field plate, cathode plate and fuel cell

Abstract

The invention discloses a fuel cell cathode flow field plate, a cathode plate and a fuel cell, the cathode flow field plate comprises a bottom plate, a hollow flow channel plate and a snake-shaped flow channel, the hollow flow channel plate is stacked and fixed on the bottom plate, and the snake-shaped flow channel comprises a steering section; wherein the hollowed-out runner plate comprises a plurality of runner ridges arranged on the bottom surface of the hollowed-out runner plate, an S-shaped hollowed-out part and at least one blade rotating assembly. The snakelike hollow part is arranged around the runner ridge; the runner ridge comprises a second end adjacent to the steering section of the snakelike runner; the blade rotating assembly comprises a fixed shaft, a rotating part and a plurality of blades, the blade rotating assembly is mounted at the second end of the runner ridge, and the blades drive the rotating part to axially rotate around the fixed shaft under the pushing of the reaction gas flow. The blade rotating assembly can effectively disperse liquid water accumulated at the corner of the flow channel, can improve the gas flow speed, and is beneficial to enhancing gas transmission and improving the water logging phenomenon.

Description

Technical Field

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

[0002] As an efficient and clean energy conversion technology, fuel cells have broad application prospects in the fields of automobiles, aerospace and industry. In the fuel cell system, the flow field plate is one of the core components. Its main function is to transfer the reaction gas and discharge liquid water, which plays a vital role in the battery performance and stability.

[0003] Traditional flow field plate designs generally adopt a serpentine flow channel structure, which improves the reaction efficiency by increasing the reaction area. However, this design has some inherent defects. When the fluid (reactant gas and liquid water) passes through the flow channel corner (the turning section of the flow channel), the fluid velocity decreases due to the change in flow direction. Therefore, the liquid water generated on the cathode side of the battery tends to accumulate at the flow channel corner to form larger water droplets or water films. The presence of these water droplets or water films will hinder the flow of the reactant gas, increase the pressure drop in the fuel cell flow field, and may cause "flooding" in some electrode reaction areas, thereby reducing the transmission efficiency of the reactant gas and affecting the overall performance of the proton exchange membrane fuel cell. In addition, the "flooding" problem may also cause physical damage to the electrode and shorten the service life of the fuel cell. Summary of the invention

[0004] The purpose of the present invention is to effectively solve the problem of accumulation of liquid water at the corners of the flow channel in the fuel cell, enhance the water management ability of the fuel cell, and thus improve the reaction gas transmission efficiency.

[0005] In order to achieve the above-mentioned object, the present invention provides a fuel cell cathode flow field plate, comprising a bottom plate, a hollow flow channel plate, and a serpentine flow channel, wherein the hollow flow channel plate is stacked and fixed on the bottom plate, and the serpentine flow channel comprises a straight flow section and a turning section; wherein the hollow flow channel plate comprises: a plurality of flow channel ridges, a serpentine hollow portion, and at least one blade rotating assembly arranged on the bottom surface of the hollow flow channel plate,

[0006] The serpentine hollow portion is arranged around the flow channel ridge;

[0007] The flow channel ridge includes a straight portion, and a first end and a second end located at both ends of the straight portion, the first end of the flow channel ridge is alternately arranged on the opposite side walls of the hollow flow channel plate, and the straight portion of the flow channel ridge extends from one side wall of the hollow flow channel plate to the other opposite side wall; the straight portions of adjacent flow channel ridges are arranged in parallel, and the first hollow structures on both sides of the straight portions of the flow channel ridge and the upper surface of the bottom plate constitute the straight flow section of the serpentine flow channel; the second hollow structure between the second end of the flow channel ridge and the side wall of the hollow flow channel plate and the upper surface of the bottom plate constitute the turning section of the serpentine flow channel; the lower surface of the second end of the flow channel ridge is provided with a recessed structure, and the recessed structure is used to install the blade rotation assembly;

[0008] The blade rotation assembly includes a fixed shaft, a rotating member, and a plurality of blades. The two ends of the fixed shaft are respectively fixed to the top surface of the recessed structure and the upper surface of the corresponding bottom plate. The fixed shaft is perpendicular to the flow direction of the reaction gas. The rotating member is sleeved on the fixed shaft. The blades are connected to the rotating member. The blades extend into the turning section of the serpentine flow channel along the radial direction of the rotating member. Under the impetus of the reaction gas flow, the blades drive the rotating member to rotate axially around the fixed shaft.

[0009] Furthermore, the blade rotation assembly includes at least 3 blades.

[0010] Furthermore, the blade rotation assembly is arranged at the second end of each of the flow channel ridges.

[0011] Furthermore, the surface of the blade is coated with a hydrophilic material.

[0012] Furthermore, the blades include any one of planar straight blades, airfoil blades, spiral blades, and beveled blades.

[0013] Furthermore, the flow channel ridge has a width of 0.5 mm to 2.5 mm, a thickness of 0.5 mm to 2.5 mm, and a length along the flow channel of 30 mm to 60 mm.

[0014] Furthermore, the serpentine flow channel has a width of 0.5 mm to 2.5 mm, a thickness of 0.5 mm to 2.5 mm, and a length along the flow path of 30 mm to 60 mm.

[0015] Furthermore, the blade has a length of 1 mm to 3 mm, a width of 0.2 mm to 0.8 mm, and a thickness of 0.25 mm to 1.25 mm.

[0016] The present invention also provides a fuel cell cathode plate, comprising the fuel cell cathode flow field plate mentioned above.

[0017] The present invention also provides a fuel cell, comprising the above-mentioned fuel cell cathode plate.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] (1) The present invention provides a rotatable blade rotating assembly at the second end of the flow channel ridge (i.e., the flow channel corner) in the cathode flow field plate of the fuel cell. On the one hand, when the reaction gas flows in the flow channel, the blades are pushed by the reaction gas flow and rotate accordingly, generating centrifugal force from the center of the blade rotating assembly to the outside and lift along the axial direction of the blade rotating assembly, effectively dispersing the accumulated liquid water, promoting the flow of liquid water accumulated at the corners of the flow channel, and preventing the occurrence of "flooding"; on the other hand, the rotatable blade rotating assembly can disturb and remove the liquid water accumulated in the flow channel, thereby effectively reducing the resistance during the flow of the reaction gas, so that the reaction gas can flow evenly in the entire flow channel, thereby reducing the pressure drop in the flow field plate; on the other hand, when the reaction gas flow rate is constant, the blades in the rotatable blade rotating assembly reduce the gas flow cross-sectional area at the corner of the flow channel, which is beneficial to increase the reaction gas flow rate, and form a certain pressure along the gas flow direction at the corner of the flow channel, which promotes the discharge of the accumulated liquid water, and to a certain extent offsets the slowing effect of the flow channel corner on the gas flow rate, thereby promoting the effective transmission of the reaction gas and improving the working efficiency of the fuel cell.

[0020] (2) Furthermore, the blades of the present invention are coated with a hydrophilic coating on the surface so that the accumulated liquid water can be drained away, thereby allowing the accumulated liquid water to be effectively dispersed through the blade rotating assembly, thereby enhancing the water management capability of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a top view of the structure of the cathode flow field plate of the fuel cell provided by the present invention.

[0022] Figure 2 A schematic structural plane diagram of a cathode flow field plate for a fuel cell provided by the present invention; wherein the shaded area represents the flow channel ridge, the blank portions on both sides of the flow channel ridge represent the serpentine hollow portions, and the black arrows represent the flow direction of the fluid.

[0023] Figure 3 for Figure 2 A partial enlarged view of the flow channel ridge and blade rotating assembly in area A; wherein a represents the front view and b represents the side view.

[0024] Description of the accompanying drawings:

[0025] Hollow channel plate 10, channel ridge 11, first end 1101 of channel ridge, second end 1102 of channel ridge, blade rotating assembly 12, serpentine hollow portion 13,

[0026] The recessed structure 111, the fixed shaft 121, the rotating member 122, the blade 123,

[0027] Bottom plate 20, reaction gas inlet 21, reaction gas outlet 22,

[0028] Serpentine flow channel 30. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The “flow channel corner” described in this article refers to the turning section of the serpentine flow channel.

[0033] In order to solve the problem of deceleration or accumulation of fluid (reactant gas and liquid water) at the corner of the flow channel (the turning section of the flow channel), the present invention proposes a design of a cathode flow field plate for a fuel cell, wherein a rotatable blade rotating assembly is arranged at the end of the flow channel ridge adjacent to the flow channel corner of the cathode flow field plate, and the blades in the blade rotating assembly can rotate under the impetus of the flow of the reactant gas. Through the rotation of the blades, the liquid water at the flow channel corner is effectively dispersed and is not easy to accumulate, thereby improving the water management capability of the fuel cell.

[0034] The present invention is described in detail below with reference to the embodiments.

[0035] like Figure 1 to Figure 2As shown, the present invention provides a fuel cell cathode flow field plate, including a bottom plate 20, a hollow flow channel plate 10, and a serpentine flow channel 30.

[0036] The hollow channel plate 10 includes: a plurality of channel ridges 11, a serpentine hollow portion 13, and at least one blade rotating assembly 12, which are arranged on the bottom surface of the hollow channel plate 10. The serpentine hollow portion 13 is arranged around the channel ridge 11, and the serpentine hollow portion 13 includes a first hollow structure and a second hollow structure that are connected. Figure 2 The blank parts on both sides of the flow channel ridge 11.

[0037] The hollow channel plate 10 is stacked and fixed on the bottom plate 20, so that the upper surface of the bottom plate 20 and the serpentine hollow portion 13 constitute the serpentine channel 30, wherein the upper surface of the bottom plate 20 constitutes the top surface of the serpentine channel 30, and the side wall of the serpentine hollow portion 13 of the hollow channel plate 10 constitutes the side wall of the serpentine channel 30. The serpentine channel 30 includes a straight flow section and a turning section, which are used to transmit reaction gas and liquid water. Wherein:

[0038] The bottom plate 20 has the same length and width as the hollow channel plate 10 and is made of the same material. The bottom plate 20 includes a reaction gas inlet 21 and a reaction gas outlet 22, and the reaction gas inlet 21 and the reaction gas outlet 22 are respectively connected to the two ends of the serpentine channel 30.

[0039] Specifically, in this embodiment, the hollow channel plate 10 is provided with 12 channel ridges 11, see Figure 2 The shaded area. The flow channel ridge 11 includes a straight portion, and a first end 1101 and a second end 1102 located at both ends of the straight portion. The first end 1101 of the flow channel ridge 11 is alternately arranged on the opposite side walls of the hollow flow channel plate 10, and the straight portion of the flow channel ridge 11 extends from one side wall of the hollow flow channel plate 10 to the other opposite side wall. The straight portions of adjacent flow channel ridges 11 are arranged in parallel, and the first hollow structures on both sides of the straight portions of the flow channel ridge 11 and the upper surface of the bottom plate 20 constitute the direct flow section of the serpentine flow channel 30. The second hollow structure between the second end 1102 of the flow channel ridge 11 and the side wall of the hollow flow channel plate 10 and the upper surface of the bottom plate 20 constitute the turning section (flow channel corner) of the serpentine flow channel 30. The cross-section of the second end of the flow channel ridge 11 is U-shaped, and the second hollow structure is U-shaped.

[0040] The present invention comprises at least one blade rotating assembly 12, see Figure 1 and Figure 2 .

[0041] Specifically, Figure 3As shown in a, the blade rotation assembly 12 includes a fixed shaft 121, a rotating member 122, and a plurality of blades 123. Among them, the fixed shaft 121 is perpendicular to the flow direction of the reaction gas, and the rotating member 122 is sleeved on the fixed shaft 121, and the rotating member 122 can rotate axially along the fixed shaft 121. The blades 123 are connected to the rotating member 122, and are evenly spaced circumferentially on the rotating member 122. The blades 123 extend into the turning section of the serpentine flow channel 30 along the radial direction of the rotating member 122. The blades 123 include but are not limited to any one of a flat straight blade, an airfoil blade, a spiral blade, and a beveled blade. In this embodiment, the fixed shaft 121 is perpendicular to the upper surface of the hollow flow channel plate 10 and the bottom plate 20. The lower surface of the second end of the flow channel ridge 11 is provided with a recessed structure 111, the center of the top surface of the recessed structure 111 is provided with a first axial hole (not shown in the figure), the corresponding position of the upper surface of the bottom plate 20 is provided with a second axial hole (not shown in the figure), and the two ends of the fixed shaft 121 are respectively fixed in the first axial hole and the second axial hole. In this embodiment, the blade rotating assembly 12 includes three blades 123, and the blades 123 are flat straight blades.

[0042] The blades 123 of the blade rotating assembly 12 can drive the rotating member 122 to rotate axially around the fixed shaft 121 under the impetus of the reaction gas flow. On the one hand, when the reaction gas flows in the serpentine flow channel 30, the blades 123 are pushed by the airflow and rotate according to the direction and speed of the reaction gas flow, generating centrifugal force from the center of the blade rotating assembly 12 to the outside, and lift along the axial direction of the blade rotating assembly 12, effectively dispersing the accumulated liquid water, promoting the flow of liquid water accumulated in the turning section (corner of the flow channel) of the serpentine flow channel 30, accelerating the discharge of liquid water, and preventing the occurrence of "flooding". On the other hand, the rotatable blade rotating assembly 12 can also reduce the pressure drop in the flow field plate while disturbing and removing the liquid water accumulated in the serpentine flow channel 30. The pressure drop refers to the pressure drop caused by friction and other flow resistance when the reaction gas flows through the flow channel. A higher pressure drop increases the energy required to pump the fluid, reducing the overall efficiency of the battery system. The blade rotating assembly 12 of the present invention effectively disperses liquid water, thereby helping to reduce resistance during the flow of the reaction gas, allowing the reaction gas to flow evenly throughout the serpentine flow channel 30, thereby reducing the pressure drop in the flow field plate and further improving the overall efficiency of the battery system.

[0043] In addition, according to the continuity equation in fluid mechanics: flow rate (Q) = flow velocity (v) × cross-sectional area (A), when the flow rate of the reactant gas introduced is constant, the flow velocity is inversely proportional to the cross-sectional area. Most of the rotatable blades 123 in the present invention extend into the flow channel, so that the gas flow cross-section at the corner of the flow channel is correspondingly reduced, thereby increasing the flow rate of the reactant gas, forming a certain pressure along the gas flow direction at the corner of the flow channel, promoting the discharge of the accumulated liquid water, and to a certain extent offsetting the slowing effect of the flow channel corner on the gas flow rate, promoting the effective transmission of the reactant gas, and further improving the working efficiency of the fuel cell.

[0044] In this embodiment, Figure 3 for Figure 2 A partial enlarged schematic diagram of the flow channel ridge 11 and the blade rotation component 12 in the A area, wherein a represents a front view and b represents a side view, in order to show the details of the blade rotation component 12 and the positional relationship between the blade rotation component 12 and the flow channel ridge 11. Specifically, to ensure that the blade 123 can rotate without hindrance, first, there is a certain gap between the edge of the blade 123 and the inner wall of the recessed structure 111, that is, the width of the blade 123 is less than the depth of the recessed structure 111, and the length of the blade is less than the distance between the first shaft hole and the side wall of the recessed structure 111, see Figure 3 b; second, there is a certain gap between the surface of the serpentine flow channel 30 and the edge of the blade 123, that is, the length of the blade 123 extending into the serpentine flow channel 30 is less than the width of the serpentine flow channel 30. In this embodiment, the width of a single flow channel ridge 11 is 2mm, the thickness is 2mm, the length along the way is 46mm, and the distance between adjacent flow channel ridges 11 is 2mm, that is, the width of the single serpentine flow channel 30 formed is 2mm, and the depth of a single serpentine structure 13 is equal to the thickness of the single flow channel ridge 11, which is 2mm. The length of a single blade 123 is 2mm, the width is 0.5mm, and the thickness is 1mm.

[0045] In this embodiment, the surface of the blade 123 is coated with a hydrophilic coating, preferably, the hydrophilic coating is polyethylene glycol (PEG), so that the surface of the blade 123 is hydrophilic, thereby having a drainage effect on the accumulated liquid water. After the liquid water is attracted to the surface of the blade 123 by the hydrophilic coating of the blade 123, the blade 123 can rotate under the impetus of the flow of the reaction gas, generating a centrifugal force outward from the center of the blade rotating component 12 and a lift along the axial direction of the blade rotating component 12, so that the liquid water can be dispersed by force and is not easy to accumulate at the corners of the flow channel, so that it is easy to be discharged from the fuel cell through the serpentine flow channel 30.

[0046] In this embodiment, preferably, see Figure 1 The blade rotating assembly 12 is disposed at the second end of each of the flow channel ridges 11, so that the liquid water at the corner of each serpentine flow channel 30 can be effectively dispersed, thereby maximizing the water management capability of the fuel cell.

[0047] In this embodiment, the reaction gas enters from the reaction gas inlet 21 of the flow field plate, passes through the serpentine flow channel 30 and the blade rotating assembly 12 at the flow channel corner, and then flows out from the reaction gas outlet 22 of the serpentine flow channel 30 together with the liquid water generated in the reaction. Figure 2 When the reaction gas flows in the serpentine flow channel 30 , the airflow passes through the blade rotating assembly 12 , and the blades 123 are pushed by the airflow and rotate accordingly, thereby dispersing the liquid water accumulated at the corners of the serpentine flow channel 30 .

[0048] In this embodiment, the method for manufacturing the cathode flow field plate comprises:

[0049] Step 1, using laser etching, first, 13 rectangular hollow structures (i.e., the first hollow structure) are sequentially and parallelly etched on the bottom surface of the hollow channel plate 10, and the straight portion of the channel ridge 11 is formed between adjacent rectangular hollow structures, and the rectangular hollow structure can constitute the direct flow section of the serpentine channel 30 with the upper surface of the bottom plate 20. Secondly, one end of the straight portion of the channel ridge 11 is alternately etched, so that a U-shaped hollow structure (i.e., the second hollow structure) is formed between one end of the straight portion of the channel ridge 11 and the side wall of the hollow channel plate 10 opposite to it, and one end of the channel ridge 11 adjacent to the U-shaped hollow structure is the second end of the channel ridge 11, and the U-shaped hollow structure can constitute the turning section of the serpentine channel 30 with the upper surface of the bottom plate 20.

[0050] In step 2, a recessed structure 111 and a first axial hole located at the center of the top surface of the recessed structure 111 are etched on the lower surface of the second end of the flow channel ridge 11, and one end of the fixed shaft 121 of the blade rotation assembly 12 is aligning and inserted into the first axial hole to install the blade rotation assembly 12 on the hollow flow channel plate 10.

[0051] Step 3, etching a second axial hole on the upper surface of the base plate 20 at a position relative to the first axial hole, aligning the other end of the fixed shaft 121 of the blade rotation assembly 12 with the second axial hole, and installing the hollow flow channel plate 10 on the upper surface of the base plate 20, so that the hollow flow channel plate 10 is stacked and fixed with the base plate 20.

[0052] In summary, the present invention provides a fuel cell cathode flow field plate, cathode plate and fuel cell with a rotatable blade rotating assembly, which enhances the liquid water management and gas transmission optimization in the fuel cell system. The blades of the blade rotating assembly can rotate axially around a fixed axis under the impetus of the reaction gas flow, generating centrifugal force and lift, causing the liquid water accumulated at the corners of the flow channel to be dispersed, thereby promoting the discharge of liquid water and helping the reaction gas to flow evenly in the flow channel. In addition, the structure reduces the cross-sectional area of ​​the gas flow at the corners of the flow channel, which is conducive to increasing the flow velocity of the reaction gas and enhancing the transmission of the reaction gas, thereby improving the working efficiency of the fuel cell.

[0053] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A fuel cell cathode flow field plate, characterized in that: It includes a bottom plate, a hollow channel plate, and a serpentine channel. The hollow channel plate is stacked and fixed on the bottom plate. The serpentine channel includes a straight section and a turning section. The hollow channel plate includes: a plurality of channel ridges, a serpentine hollow portion, and at least one blade rotating component arranged on the bottom surface of the hollow channel plate. The serpentine hollow portion is arranged around the flow channel ridge; The flow channel ridge includes a straight portion, and a first end and a second end located at both ends of the straight portion, the first end of the flow channel ridge is alternately arranged on the opposite side walls of the hollow flow channel plate, and the straight portion of the flow channel ridge extends from one side wall of the hollow flow channel plate to the other opposite side wall; the straight portions of adjacent flow channel ridges are arranged in parallel, and the first hollow structures on both sides of the straight portions of the flow channel ridge and the upper surface of the bottom plate constitute the straight flow section of the serpentine flow channel; the second hollow structure between the second end of the flow channel ridge and the side wall of the hollow flow channel plate and the upper surface of the bottom plate constitute the turning section of the serpentine flow channel; the lower surface of the second end of the flow channel ridge is provided with a recessed structure, and the recessed structure is used to install the blade rotation assembly; The blade rotation assembly includes a fixed shaft, a rotating member, and a plurality of blades. The two ends of the fixed shaft are respectively fixed to the top surface of the recessed structure and the upper surface of the corresponding bottom plate. The fixed shaft is perpendicular to the flow direction of the reaction gas. The rotating member is sleeved on the fixed shaft. The blades are connected to the rotating member. The blades extend into the turning section of the serpentine flow channel along the radial direction of the rotating member. Under the impetus of the reaction gas flow, the blades drive the rotating member to rotate axially around the fixed shaft.

2. The fuel cell cathode flow field plate according to claim 1, characterized in that: The blade rotating assembly includes at least three blades.

3. The fuel cell cathode flow field plate according to claim 1, characterized in that: The blade rotation assembly is disposed at the second end of each of the flow channel ridges.

4. The fuel cell cathode flow field plate according to claim 1, characterized in that: The surface of the blade is coated with a hydrophilic material.

5. The fuel cell cathode flow field plate according to claim 1, characterized in that: The blades include any one of a flat straight blade, an airfoil blade, a spiral blade, and a beveled blade.

6. The fuel cell cathode flow field plate according to claim 1, characterized in that: The flow channel ridge has a width of 0.5 mm to 2.5 mm, a thickness of 0.5 mm to 2.5 mm, and a length along the flow channel of 30 mm to 60 mm.

7. The fuel cell cathode flow field plate according to claim 6, characterized in that: The serpentine flow channel has a width of 0.5 mm to 2.5 mm, a thickness of 0.5 mm to 2.5 mm, and a length along the way of 30 mm to 60 mm.

8. The fuel cell cathode flow field plate according to claim 7, characterized in that: The blade has a length of 1 mm to 3 mm, a width of 0.2 mm to 0.8 mm, and a thickness of 0.25 mm to 1.25 mm.

9. A fuel cell cathode plate, characterized in that: A fuel cell cathode flow field plate comprising any one of claims 1-8.

10. A fuel cell, characterized in that: The fuel cell cathode plate comprises the fuel cell cathode plate as claimed in claim 9.

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