Flow field structure, polar plate and electric pile

Abstract

The invention relates to the technical field of fuel cells, and discloses a flow field structure, a pole plate and a galvanic pile, the flow field structure comprises a plurality of parallel equidistant linear flow channel ridges and a plurality of parallel equidistant broken-line-shaped flow channel ridges, the plurality of linear flow channel ridges and the plurality of broken-line-shaped flow channel ridges are arranged in a staggered manner, a flow channel is formed between the adjacent broken-line-shaped flow channel ridge and the linear flow channel ridge; a notch is formed in each break angle of the broken-line-shaped runner ridge, is positioned on one side of the broken-line-shaped runner ridge, and is positioned between two adjacent runners; when the gas is conveyed through the flow channel, the gas can be subjected to electrochemical reaction with the catalyst layer on the membrane electrode, and as the cross section of the flow channel is different in width, the flow rate of the gas is continuously changed, the electrochemical efficiency of the polar plate can be improved, the water accumulation phenomenon on the gas diffusion layer of the membrane electrode is relieved, and the water logging phenomenon is avoided.

Description

Technical Field

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

[0002] With the continuous development of the new energy industry, fuel cells are being used in more and more scenarios. Fuel cells are energy conversion devices that can directly convert chemical energy from hydrogen and other reaction fuels into electrical energy through electrochemical reactions. They have broad development and application prospects in the future due to their high power density, fast start-up speed, high conversion efficiency, low environmental pollution, easy access to raw materials, clean and efficient.

[0003] The fuel cell includes a membrane electrode and a bipolar plate. The bipolar plate is fixed on both sides of the membrane electrode to separate the oxidant, the reductant and the coolant. The membrane electrode includes a gas diffusion layer and a catalyst layer. The oxidant or the reductant passes through the gas diffusion layer and reacts in the catalyst layer.

[0004] Most of the existing plates adopt the form of straight flow channels or wavy flow channels. Water will be generated during the reaction process. The generated water is easy to accumulate in the gas diffusion layer, affecting the continued reaction of the fuel cell. Summary of the invention

[0005] The purpose of the present invention is to provide a flow field structure, a plate and a battery stack to solve the following technical problems:

[0006] How to prevent the water generated during the reaction of fuel cells from accumulating in the gas diffusion layer?

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] In the first aspect, the present invention discloses a flow field structure, comprising a plurality of parallel and equidistantly arranged straight flow channel ridges, a plurality of parallel and equidistantly arranged zigzag flow channel ridges, the plurality of straight flow channel ridges and the plurality of zigzag flow channel ridges being staggered, and flow channels being formed between adjacent zigzag flow channel ridges and straight flow channel ridges.

[0009] In a further embodiment of the present invention, a notch is provided at each corner of the zigzag flow channel ridge, and the notch is located on one side of the zigzag flow channel ridge and between two adjacent flow channels.

[0010] In a further embodiment of the present invention, two ends of a plurality of straight flow channel ridges are aligned with two ends of a plurality of folded-line flow channel ridges.

[0011] In a second aspect, the present invention discloses a polar plate, including a polar plate body, one side of the polar plate body is provided with the flow field structure as described above, and the notch in the flow field structure is located on a side away from the polar plate body.

[0012] In a further embodiment of the present invention, the electrode body is provided with an air inlet and an air outlet at both ends of a flow field structure, wherein an air inlet distribution area is provided between the air inlet and one end of the flow field structure, and an air outlet distribution area is provided between the air outlet and the other end of the flow field structure.

[0013] In a further embodiment of the present invention, the air inlet distribution area and the air outlet distribution area are both composed of a plurality of evenly distributed bosses.

[0014] In a third aspect, the present invention further discloses a fuel cell stack, comprising a core and combined plates installed at both ends of the core, wherein the core is composed of membrane electrodes and the pole plates as described above stacked alternately.

[0015] In a further embodiment of the present invention, the combined plate comprises a current collecting plate, an insulating plate and an end plate, and the current collecting plate, the insulating plate and the end plate are stacked in sequence from the inside to the outside on the end side of the core.

[0016] Beneficial effects of the present invention:

[0017] (1) In the flow channel structure of the present invention, when the gas is transported through the flow channel, it will undergo an electrochemical reaction with the catalyst layer on the membrane electrode. Since the cross-section of the flow channel varies in width, the gas flow rate constantly changes and turbulence occurs. The gas constantly collides with the catalyst layer, so the contact reaction between the gas and the catalyst layer is intensified, which is beneficial to promote the electrochemical reaction between the gas and the membrane electrode and improve the electrochemical efficiency of the electrode plate.

[0018] (2) When the gas flows to the narrowest part of the flow channel, the flow velocity reaches the maximum and the pressure decreases. At this time, under the action of gas pressure, the gas in the adjacent flow channel will spread to the flow channel along the notch on the zigzag flow channel ridge. On the one hand, it can avoid the separation between the electrode plate and the membrane electrode caused by excessive pressure. On the other hand, when the gas flows from the adjacent flow channel to the narrow cross-section flow channel and passes through the notch, the gas will also contact the membrane electrode, thereby carrying the water generated by the electrochemical reaction on the gas diffusion layer of the membrane electrode to the narrow cross-section flow channel, and moving with the gas in the flow channel until it is discharged, thereby alleviating the accumulation of water on the gas diffusion layer of the membrane electrode and avoiding the occurrence of flooding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] Figure 1 is a schematic structural diagram of the flow field structure in Example 1 of the present invention;

[0021] Figure 2 yes Figure 1 A is a schematic diagram of the enlarged structure of the middle part;

[0022] Figure 3 is a schematic diagram of the structure of the electrode plate in Example 2 of the present invention;

[0023] Figure 4 is a schematic diagram of the three-dimensional structure of the electrode plate in Example 2 of the present invention;

[0024] Figure 5 yes Figure 4 A schematic diagram of the enlarged structure of B;

[0025] Figure 6 It is a schematic diagram of the structure of the battery stack in Example 3 of the present invention.

[0026] In the figure: 100, straight flow channel ridge; 200, zigzag flow channel ridge; 201, notch; 300, plate body; 301, air inlet; 302, air inlet distribution area; 303, air outlet; 304, air outlet distribution area; 400, core; 500, combined plate; 501, current collecting plate; 502, insulating plate; 503, end plate. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] See also Figure 1-2 As shown, this embodiment discloses a flow field structure, including a plurality of parallel and equidistantly arranged straight flow channel ridges 100 and a plurality of parallel and equidistantly arranged zigzag flow channel ridges 200, wherein the plurality of straight flow channel ridges 100 and the zigzag flow channel ridges 200 are staggered, and a flow channel is formed between adjacent zigzag flow channel ridges 200 and the straight flow channel ridges 100, and the gas flows in from one end of the flow channel, flows in the flow channel and flows out from the other end of the flow channel.

[0030] Since the zigzag flow channel ridges 200 are regularly arranged zigzag shapes, the width of the flow channel cross section formed between the zigzag flow channel ridges 200 and the straight flow channel ridges 100 varies in width, and the cross-sectional dimensions of adjacent flow channels at the same position are opposite; when the gas flows in the flow channel, the cross-sectional width of the flow channel changes continuously, showing a regular change of width and narrowness, so the flow rate of the gas also changes continuously in a staggered manner, thereby causing turbulence in the gas.

[0031] Furthermore, a notch 201 is provided at each corner of the zigzag flow channel ridge 200 . The notch 201 is located on one side of the zigzag flow channel ridge 200 and is connected between two adjacent flow channels.

[0032] When the gas flows in the flow channel, once the gas flows to the narrowest part of the flow channel cross section, the gas flow rate reaches the maximum and the pressure becomes smaller. Therefore, the gas in the adjacent flow channel will spread to the flow channel through the notch 201 at the corner of the zigzag flow channel ridge 200, and can continue to move forward with the flow channel gas.

[0033] Furthermore, two ends of the linear flow channel ridge 100 are respectively aligned with two ends of the folded-line flow channel ridge 200 to ensure that the air inlet position and the air outlet position of each flow channel are flush.

[0034] Example 2

[0035] See also Figure 3-5 This embodiment discloses a plate based on the embodiment 1, which includes a plate body 300, one side of the plate body 300 is provided with the flow field structure in the embodiment 1, and the notch 201 in the flow field structure is located on the side away from the plate body 300.

[0036] The plate body 300 is provided with an air inlet 301 and an air outlet 303 at both ends of one side of the flow field structure, wherein an air inlet distribution area 302 is provided between the air inlet 301 and one end of the flow field structure, and an air outlet distribution area 304 is provided between the air outlet 303 and the other end of the flow field structure. The air inlet distribution area 302 and the air outlet distribution area 304 are both composed of a number of evenly distributed bosses, and the shape structure of the bosses is not specifically limited, and may be triangular, rectangular, waist-shaped or other convex structures. In the present embodiment, the shape structure of the bosses is a circular convex structure.

[0037] Specifically, when in use, the side of the electrode body 300 provided with the flow field structure is attached to the membrane electrode, then, the gas enters from the air inlet 301, enters the flow channel inlet through the air inlet distribution area 302, is transported through the flow channel, flows from the flow channel outlet through the air outlet distribution area 304 to the air outlet 303, and is finally discharged from the air outlet 303.

[0038] When the gas is transported through the flow channel, it will undergo an electrochemical reaction with the catalyst layer on the membrane electrode. Since the cross-section of the flow channel varies in width, the gas flow rate constantly changes, thereby generating turbulence. The gas constantly collides with the catalyst layer, so the contact reaction between the gas and the catalyst layer intensifies, which is beneficial to promote the electrochemical reaction between the gas and the membrane electrode and improve the electrochemical efficiency of the electrode plate.

[0039] At the same time, when the gas flows to the narrowest part of the flow channel cross-section, the flow velocity reaches the maximum and the pressure becomes smaller. At this time, under the action of air pressure, the gas in the adjacent flow channel will spread to the flow channel along the notch 201 on the zigzag flow channel ridge 200. On the one hand, it can avoid the separation between the electrode plate and the membrane electrode caused by excessive pressure. On the other hand, when the gas flows from the adjacent flow channel to the narrow-section flow channel and passes through the notch 201, the gas will also contact the membrane electrode, thereby carrying the water generated by the electrochemical reaction on the gas diffusion layer of the membrane electrode to the narrow-section flow channel, and moving with the gas in the flow channel until it is discharged, thereby alleviating the accumulation of water on the gas diffusion layer of the membrane electrode and avoiding the occurrence of flooding.

[0040] Example 3

[0041] See also Figure 6 This embodiment discloses a fuel cell stack based on the embodiment 2, including a core 400 and a combination plate 500 installed at both ends of the core, wherein the core 400 is composed of membrane electrodes and the plates in the embodiment 2 stacked alternately, and has the functions of fast electrochemical efficiency and anti-flooding.

[0042] Furthermore, the combined plate 500 includes a current collecting plate 501, an insulating plate 502 and an end plate 503, which are stacked in sequence from the inside to the outside on the end side of the core 400 to form a complete battery stack that can be used in fuel cells.

[0043] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying 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 direction and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present invention. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. 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 or an electrical connection; it can be a direct connection, or it can be an indirect connection 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.

[0045] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A flow field structure, characterized in that: The invention comprises a plurality of linear flow channel ridges (100) arranged in parallel and equidistantly, and a plurality of zigzag flow channel ridges (200) arranged in parallel and equidistantly. The plurality of linear flow channel ridges (100) and the plurality of zigzag flow channel ridges (200) are arranged in a staggered manner, and flow channels are formed between adjacent zigzag flow channel ridges (200) and linear flow channel ridges (100).

2. The flow field structure according to claim 1, characterized in that: A notch (201) is provided at each corner of the folded-line flow channel ridge (200), and the notch (201) is located on one side of the folded-line flow channel ridge (200) and between two adjacent flow channels.

3. The flow field structure according to claim 1, characterized in that: Two ends of the plurality of straight-line flow channel ridges (100) are respectively aligned with two ends of the plurality of folded-line flow channel ridges (200).

4. A plate, comprising a plate body (300), characterized in that: A flow field structure as claimed in any one of claims 1 to 3 is arranged on one side of the electrode plate body (300), and the notch (201) in the flow field structure is located on the side away from the electrode plate body (300).

5. The electrode plate according to claim 4, characterized in that: The electrode plate body (300) is provided with an air inlet (301) and an air outlet (303) at both ends of a flow field structure, wherein an air inlet distribution area (302) is provided between the air inlet (301) and one end of the flow field structure, and an air outlet distribution area (304) is provided between the air outlet (303) and the other end of the flow field structure.

6. The electrode plate according to claim 5, characterized in that: The air inlet distribution area (302) and the air outlet distribution area (304) are both composed of a number of evenly distributed bosses.

7. A fuel cell stack, comprising a core (400) and assembly plates (500) mounted at both ends of the core, characterized in that: The core (400) is composed of membrane electrodes and electrode plates described in any one of Examples 4-6 stacked alternately.

8. The battery stack according to claim 7, characterized in that: The combined plate (500) comprises a current collecting plate (501), an insulating plate (502) and an end plate (503), and the current collecting plate (501), the insulating plate (502) and the end plate (503) are stacked in sequence from the inside to the outside on the end side of the core (400).

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