CN116979081A - Conical multi-channel of fuel cell with blocking structure - Google Patents

Abstract

The invention provides a conical multi-channel fuel cell with a blocking structure. A number of parallel conical channels are provided between the total inlet of the reactant gas channel and the total outlet of the reactant gas channel. The flow area of the conical channel gradually increases along the flow direction. shrink; each of the tapered channels is provided with blocking components spaced apart on both sides, and the blocking components on both sides reduce the cross-sectional area of the upper part of the tapered channel. Each group of the blocking components includes a pair of blocking structures. , the blocking structure is a pit structure, and a pair of blocking structures with the same cross-section are provided on both sides of the tapered channel. One end of the blocking structure is connected to the upper part of the tapered channel, and the other end of the blocking structure is connected to the tapered channel. There is a gap between the lower parts of the channels. The invention effectively prevents spherical droplets from clogging the channel outlet, and the water film only moves on the side wall and top wall of the flow channel, thereby reducing the water content on the surface of the gas diffusion layer.

Description

A conical multi-channel fuel cell with blocking structure

Technical field

The invention relates to the technical field of proton exchange membrane fuel cells, and is a conical multi-channel fuel cell with a blocking structure.

Background technique

With the transformation and upgrading of energy, hydrogen energy has ushered in the peak of use due to its advantages of cleanliness, renewable and large reserves. In the field of power, proton exchange membrane fuel cells powered by hydrogen are considered to be an effective and reliable alternative to traditional energy sources due to their renewable energy, no carbon emissions, and high power density. Proton exchange membrane fuel cells use hydrogen and air as reactants to perform electrochemical reactions, converting the chemical energy produced into electrical energy to provide a source of power. Water is the only product of the reaction, and good management of it is an important means to improve the performance of proton exchange membrane fuel cells. Liquid water is the main product. It is generated in the catalytic layer and penetrates into the flow channel through the gas diffusion layer, and is discharged from the inside of the fuel cell through the purge effect of gas. Therefore, the flow channel is the final place for liquid water removal. When too much liquid water accumulates in the flow channel, a "flooding" phenomenon occurs, which blocks the transmission of reaction gases and prevents the battery from working properly. This is also a major problem that hinders the commercial application of proton exchange membrane fuel cells.

Although the removal of liquid water in the flow channel is affected by gas, the material, shape and structure of the flow channel will have a great impact on the movement of liquid water and determine the drainage performance of the entire flow field. Among them, the structure and shape design of flow channels are the most common research content in this technical field. Good flow channel design will greatly improve the performance of proton exchange membrane fuel cells in engineering applications and bring higher economic benefits. Among the current types of flow channels, straight flow channels, serpentine flow channels, bionic flow channels and grid flow channels are widely developed and used. Due to the cone angle, the tapered flow channel causes a sudden change in pressure drop at the outlet, which can increase the drainage speed of the flow channel, and has begun to become the focus of technical personnel.

But at the same time, the smaller cross-section at the outlet of the tapered flow channel will cause a sudden increase in pressure, causing uneven distribution of reaction gases in the channel, and will also adversely affect the performance of the fuel cell. In the existing technology, the structural design to improve the drainage speed in the conical channel is insufficient. At the same time, most research mainly focuses on the structural design of a single channel, which is not enough for the entire flow field of the fuel cell.

Contents of the invention

In view of the deficiencies in the prior art, the present invention provides a conical multi-channel fuel cell with a blocking structure. The present invention designs a blocking component on the tapered channel. The tapered channel can be composed of several channels connected in parallel, so The blocking structures on both sides of the tapered channel are spaced apart from the inlet. The blocking components on both sides reduce the cross-sectional area of the upper part of the tapered channel, allowing liquid water to form a columnar water film at the outlet of the channel and then flow into the flow channel. Movement on the top and side walls effectively prevents spherical droplets from clogging the channel outlet, and the water film only moves on the side and top walls of the flow channel, reducing the water content on the surface of the gas diffusion layer (GDL) and increasing the channel inlet. pressure, which reduces the pressure difference between the inlet and outlet of the tapered channel. Coupled with the existence of the liquid film, the reaction gas distribution is more uniform, and the structure is simply processed on the existing channel, without the need to add additional blocking blocks, reducing processing costs. .

The present invention achieves the above technical objectives through the following technical means.

A fuel cell cone-shaped multi-channel with a blocking structure. A number of parallel conical channels are provided between the total inlet of the reactant gas channel and the total outlet of the reactant gas channel. The flow area of the conical channel gradually shrinks along the flow direction; each The two sides of the tapered channel are provided with blocking components spaced apart, and the blocking components on both sides reduce the cross-sectional area of the upper part of the tapered channel, so that liquid water can exit from the tapered channel in a liquid film-like manner. outflow.

Further, each group of the blocking components includes a pair of blocking structures. The blocking structures are pit structures. A pair of blocking structures with the same cross-section are provided on both sides of the tapered channel. One end of the blocking structure is connected to the tapered channel. The upper part of the channel is connected, and there is a gap between the other end of the blocking structure and the lower part of the tapered channel.

Further, the distance between the first blocking component in each tapered channel and the entrance of the tapered channel is 10% to 20% of the length of the tapered channel; the distance between the last blocking component in each tapered channel and the exit of the tapered channel is 10% to 20% of the length of the tapered channel. 30% to 40% of the channel length.

Further, each tapered channel is divided into a first half tapered channel and a second half tapered channel through the midpoint position, and the number of blocking components of the first half tapered channel is greater than the number of blocking components of the second half tapered channel, The number of blocking components of the second half of the tapered channel is 60-70% of the number of blocking components of the first half of the tapered channel.

Further, the width of the blocking structure in the blocking assembly increases along the flow direction, and the depth of the blocking structure in the blocking assembly increases along the flow direction; the length of the blocking structure in the blocking assembly is 0.5 mm to 1 mm.

Further, the width of the blocking structure in the first blocking component in the tapered channel is 0.1mm~0.2mm; the width difference between the blocking structures in the adjacent blocking components is 0.05mm; the width of the blocking structure is not More than 70% of the tapered channel height.

Further, the depth of the pit structure in the first blocking component in the tapered channel is 0.1mm~0.12mm; the depth difference between the blocking structures in the adjacent blocking components is 0.01mm; the height of the blocking structure No more than 40% of the tapered channel width.

Further, the distance between adjacent blocking components is 1% to 10% of the length of the tapered channel.

Further, the cross-sectional shape of the blocking structure is rectangular, triangular, trapezoidal, or circular.

Further, the height of the outlet of the tapered channel is smaller than the height of the entrance of the tapered channel, and the height of the entrance of the tapered channel is 0.4~0.6mm; the height of the exit of the tapered channel is 0.2~0.4mm; between adjacent tapered channels The spacing is 0.75~1mm.

The beneficial effects of the present invention are:

1. The fuel cell conical multi-channel with a blocking structure according to the present invention, the tapered channel has a flow area that gradually shrinks along the flow direction; each of the tapered channels is provided with blocking components spaced apart on both sides, and both sides The blocking component of the present invention reduces the cross-sectional area of the upper part of the tapered channel. The existence of the blocking component of the present invention can increase the viscous force between the flow channel wall and the liquid water, causing the liquid water to form a liquid film in a film-like manner. Discharging from the channel outlet greatly reduces the water coverage at the bottom of the flow channel, that is, the surface of GDL, which is beneficial to improving battery performance. It also prevents larger spherical droplets from clogging the outlet of the tapered channel and preventing the flow channel from being able to drain water.

2. The fuel cell conical multi-channel with a blocking structure according to the present invention, the height of the pit structure in the blocking assembly increases along the flow direction, and the depth of the pit structure in the blocking assembly increases along the flow direction; because At the outlet of the channel, liquid water is also transported in the form of a film instead of a droplet, which reduces the blockage of gas by large droplets, makes the change of air flow velocity gentle, and improves the uniformity of gas distribution.

3. The fuel cell conical multi-channel with blocking structure according to the present invention, the conical channel has a tapered circulation area along the flow direction. Since the pressure is increased at the channel inlet, the inlet and outlet pressure difference is reduced, and the cone-shaped channel is relieved. The sudden change in air flow pressure at the outlet of the shaped channel is beneficial to improving the performance of the fuel cell.

4. In the conical multi-channel fuel cell with blocking structure of the present invention, the blocking component is processed on the tapered channel, without the need to add additional blocking blocks, which reduces the processing cost.

Description of the drawings

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are of the present invention. For some embodiments, it is obvious to those of ordinary skill in the art that other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of a conical multi-channel fuel cell with a blocking structure according to the present invention.

Figure 2 is a top view of a conical multi-channel fuel cell with a blocking structure according to the present invention.

FIG. 3 is a cross-sectional view along line A-A of FIG. 2 .

Figure 4 is a comparison diagram of the transport behavior of liquid water in the embodiments of the present invention and the comparative examples.

Figure 5 is a velocity distribution cloud diagram of the reaction gas in the embodiments and comparative examples of the present invention.

Figure 6 is a comparison chart of GDL surface water coverage in the embodiments of the present invention and comparative examples.

Figure 7 is a comparison chart of inlet pressure between the embodiment of the present invention and the comparative example.

In the picture:

1-tapered channel; 2-blocking structure; L ₁ - tapered channel length; L ₂ - pit structure length; W ₁ - tapered channel width; W ₂ - pit structure width; S ₁ - tapered channel spacing ; S ₂ - pit structure spacing; D - pit structure depth; H ₁ - conical channel entrance height; H ₂ - conical channel exit height.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", The orientations or positional relationships indicated by "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships 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 operate in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrally connected; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

As shown in Figures 1, 2 and 3, the conical multi-channel fuel cell with blocking structure of the present invention has a number of parallel tapered channels between the main inlet of the reaction gas channel and the main outlet of the reaction gas channel. 1. The flow area of the tapered channel 1 gradually shrinks along the flow direction; blocking components are arranged at intervals on both sides of each tapered channel 1, and the blocking components on both sides make the cross section of the upper part of the tapered channel 1 The area becomes smaller, which is used to make the liquid water flow out from the outlet of the tapered channel 1 in a liquid film shape. The blocking component of the present invention can increase the viscous force between the wall surface of the flow channel and the liquid water, causing the liquid water to form a liquid film and be discharged from the channel outlet in a film-like manner, which greatly reduces the pressure at the bottom of the flow channel, that is, The water coverage on the GDL surface is beneficial to improving battery performance. It also prevents larger spherical droplets from clogging the outlet of the tapered channel and preventing the flow channel from being able to drain water.

Each group of the blocking components includes a pair of blocking structures 2. The blocking structures 2 are pit structures, and the cross-sectional shapes of the pit structures are rectangular, triangular, trapezoidal, circular, or other polygonal shapes. A pair of blocking structures 2 with the same cross-section are provided on both sides of the tapered channel 1. One end of the blocking structure 2 is connected to the upper part of the tapered channel 1, and the other end of the blocking structure 2 is connected to the lower part of the tapered channel 1. There is a gap, as shown in Figure 3. Such a structure enables liquid water to form a columnar water film at the channel outlet and then move on the top and side walls of the channel, effectively preventing spherical droplets from blocking the channel outlet, and the water film only moves on the side and top walls of the channel. , reduce the water content on the surface of the gas diffusion layer (GDL). The exit height of the tapered channel 1 is smaller than the entrance height of the tapered channel 1. The exit height _H2 of the tapered channel 1 is 0.2~0.4mm; the entrance height H1 of the tapered channel ₁ is 0.4~0.6mm; adjacent The tapered channel spacing S ₁ between the tapered channels 1 is 0.75 to 1 mm.

The distance between the first blocking component in each tapered channel 1 and the entrance of tapered channel 1 is 10% to 20% of the length of tapered channel 1; the distance between the last blocking component in each tapered channel 1 and the exit of tapered channel 1 It is 30% to 40% of the length of the tapered channel 1. Each tapered channel 1 is divided into a first half tapered channel and a second half tapered channel through the midpoint position. The number of blocking components of the first half tapered channel is greater than the number of blocking components of the second half tapered channel, so The number of blocking components in the second half of the tapered channel is 60 to 70% of the number of blocking components in the first half of the tapered channel.

The height of the pit structure in the blocking assembly increases along the flow direction, and the depth of the pit structure in the blocking assembly increases along the flow direction; the length L ₂ of the pit structure in the blocking assembly is 0.5 mm to 1 mm. The width W ₂ of the pit structure in the first blocking component in the tapered channel 1 is 0.1mm to 0.2mm; the width difference between the pit structures in the adjacent blocking components is 0.05mm; the pit The width of the structure shall not exceed 70% of the entrance height H ₁ of the tapered channel 1. The depth D of the pit structure in the first blocking component in the tapered channel 1 is 0.1mm to 0.12mm; the depth difference between the pit structures in the adjacent blocking components is 0.01mm; the pit structure The height does not exceed 40% of the width W ₁ of the tapered channel 1. The pit structure spacing S ₂ between adjacent blocking components is 1% to 10% of the length of the tapered channel 1 .

Example 1

This embodiment provides a cone-shaped multi-channel fuel cell with a blocking structure. Its partial three-dimensional schematic diagram is shown in Figure 1, and its partial top view and side view are shown in Figure 2. The fuel cell flow channel is made of 304 stainless steel. The length L ₁ of the tapered channel 1 is 13 mm, the width W ₁ of the tapered channel 1 is 4.5 mm, and it is composed of three tapered single channels connected in parallel. Among them, the three single channels have the same structure and size parameters. The cross-sectional area of the tapered channel 1 at the entrance is 0.6mm×0.6mm, the exit height _H2 of the tapered channel 1 is 0.4mm, the height difference between the entrance and the exit is 0.2mm, and the tapered channel spacing _S1 is 0.8mm.

On both sides of the tapered channel 1, blocking assemblies are evenly spaced. Each group of the blocking components includes a pair of blocking structures 2. The blocking structures are rectangular in shape and are arranged starting from the entrance of the tapered channel 1. The first blocking structure is 1.5mm away from the entrance. A pair of blocking structures 2 are arranged at intervals of 1mm. It ends 5mm from the exit of tapered channel 1. At the same time, when more than half of the tapered channel is exceeded, the number of blocking structures is reduced to 2, the number in the first half is 3, and the number in the second half is 2. Among them, the first blocking structure has a height of 0.2mm and a depth of 0.12mm; the third blocking structure has a height of 0.3mm and a depth of 0.13mm; the fifth blocking structure has a height of 0.4mm and a depth of 0.14mm. The lengths of all blocking structures are 0.6mm.

In addition, a fuel cell cone-shaped multi-channel without the cross-section gradually expanding blocking structure is used as a comparative example, and has the same size parameters as Example 1.

Compared with the comparative example, Embodiment 1 of the present invention has the following obvious advantages:

Compared with the conical multi-channel fuel cell without the gradually expanding cross-section blocking structure, the present invention greatly promotes the water management performance. As shown in Figure 4, the liquid water at the channel outlet is in the form of a film flow in the embodiment, but in the form of a droplet flow in the comparative example. It shows that the gradually expanding cross-section blocking structure changes the movement mode of liquid water, allowing liquid water to emerge from the channel in the form of a thin film and discharge from the channel, preventing larger droplets from blocking the channel.

It can be found from Figure 5 that the blocking structure of the present invention is beneficial to the uniformity of air flow distribution in the tapered channel. At the outlet, the air flow velocity changes obviously abruptly in the comparative example, but this is improved in this embodiment. In the comparative example, due to the presence of larger droplets at the channel outlet, the gas was blocked and the change in gas flow velocity was intensified. In this embodiment, the liquid film at the channel outlet causes the gas flow velocity to change more slowly, which makes the reaction gas more uniformly distributed in the tapered channel. And it is found from the figure that the blocking structure has a certain effect on increasing the air flow speed of the conical multi-channel of the fuel cell.

It can be seen from Figure 6 that the surface water coverage of GDL in the embodiment of the present invention is obviously smaller than that in the comparative example. It shows that the tapered multi-channel with blocking structure of the present invention can reduce the content of liquid water adhering to the GDL surface. This is because the liquid water mainly moves on the flow channel wall in the form of film flow in the embodiment and does not reach The bottom of the flow channel, which is the GDL surface, is beneficial to the transportation of reaction gas and liquid water.

It can be seen from Figure 7 that the pressure at the channel inlet in the embodiment of the present invention is significantly greater than that in the comparative example. It shows that the conical multi-channel of the blocking structure of the present invention can increase the pressure in the inlet section, reduce the pressure difference between the inlet and the outlet, and alleviate the sudden pressure change phenomenon at the outlet of the tapered channel.

It should be understood that although this specification is described in terms of various embodiments, not each embodiment only contains an independent technical solution. This description of the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole. , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the protection scope of the present invention. Any equivalent embodiments or embodiments that do not deviate from the technical spirit of the present invention are not intended to limit the protection scope of the present invention. All changes should be included in the protection scope of the present invention.

Claims (10)

1. The conical multi-channel fuel cell with the blocking structure is characterized in that a plurality of parallel conical channels (1) are arranged between a total inlet of the reaction gas channel and a total outlet of the reaction gas channel, and the conical channels (1) are gradually reduced in flow direction and flow area; blocking assemblies are arranged on two sides of each conical channel (1) at intervals, the cross-sectional area of the upper part of each conical channel (1) is reduced by the blocking assemblies on two sides, and liquid water flows out of the outlet of each conical channel (1) in a liquid film mode.

2. The tapered multi-channel with blocking structure for fuel cells according to claim 1, wherein each group of the blocking assemblies comprises a pair of blocking structures (2), the blocking structures (2) are pit structures, a pair of blocking structures (2) with the same cross section are correspondingly arranged at two sides of the tapered channel (1), one end of each blocking structure (2) is connected with the upper part of the tapered channel (1), and a gap is arranged between the other end of each blocking structure (2) and the lower part of the tapered channel (1).

3. The tapered multiple channel with blocking structure for fuel cells according to claim 2, characterized in that the first blocking component in each tapered channel (1) is at a distance of 10% to 20% of the length of the tapered channel (1) from the entrance of the tapered channel (1); the distance between the last blocking component in each conical channel (1) and the outlet of the conical channel (1) is 30-40% of the length of the conical channel (1).

4. The tapered multiple channels with blocking structure for fuel cells according to claim 2, wherein each tapered channel (1) is divided into a front half tapered channel and a rear half tapered channel by a midpoint position, the number of blocking elements of the front half tapered channel is greater than the number of blocking elements of the rear half tapered channel, and the number of blocking elements of the rear half tapered channel is 60 to 70% of the number of blocking elements of the front half tapered channel.

5. The fuel cell tapered multichannel with blocking structure according to claim 2, characterized in that the width of the blocking structure (2) in the blocking assembly increases in the flow direction and the depth of the blocking structure (2) in the blocking assembly increases in the flow direction; the length of the blocking structure (2) in the blocking assembly is 0.5 mm-1 mm.

6. The fuel cell conical multi-channel with blocking structure according to claim 5, characterized in that the width of the blocking structure (2) in the first blocking assembly in the conical channel (1) is 0.1 mm-0.2 mm; the width difference of the blocking structures (2) in adjacent blocking assemblies is 0.05mm; the width of the blocking structure (2) does not exceed 70% of the height of the tapered channel (1).

7. The fuel cell conical multi-channel with blocking structure according to claim 5, characterized in that the depth of the blocking structure (2) in the first blocking assembly in the conical channel (1) is 0.1 mm-0.12 mm; the depth difference of the blocking structures (2) in adjacent blocking assemblies is 0.01mm; the height of the blocking structure (2) does not exceed 40% of the width of the tapered channel (1).

8. The tapered multiple channel with blocking structure for fuel cells of claim 5, wherein the spacing between adjacent blocking assemblies is 1% to 10% of the length of the tapered channel (1).

9. The fuel cell conical multi-channel with blocking structure according to claim 2, characterized in that the cross-sectional shape of the blocking structure (2) is rectangular or triangular or trapezoidal or circular.

10. The tapered multi-channel with blocking structure for fuel cells according to any one of claims 1 to 9, wherein the outlet height of the tapered channel (1) is smaller than the inlet height of the tapered channel (1), and the inlet height of the tapered channel (1) is 0.4 to 0.6mm; the height of the outlet of the conical channel (1) is 0.2-0.4 mm; the distance between the adjacent conical channels (1) is 0.75-1 mm.