阅读说明：本技术 一种双重强化对流的质子交换膜燃料电池流道 (Proton exchange membrane fuel cell flow channel with double enhanced convection ) 是由 袁伟 赵永豪 何洁雯 柯育智 林惠铖 李锦广 刘庆森 梁浩伟 李晋宇 于 2021-07-31 设计创作，主要内容包括：本发明公开的一种双重强化对流的质子交换膜燃料电池流道,包括置于流场板上的电池流道,所述电池流道两侧设有若干个弧形缺口单元阵列,每个弧形缺口单元的一侧为斜面,两侧相邻的两个弧形缺口单元通过斜面形成通道；在流道入口处,气体经过弧形缺口在横向上强化对流传递,同时在纵向的斜面通道强化向下层催化层的传递效应,使得催化层内氧气的分布更为充分,显著增强了流道中气体的速度,有利于气体的扩散传输和产物水的排出,从而提高了电池性能。(The invention discloses a dual-enhanced convection proton exchange membrane fuel cell flow channel, which comprises a cell flow channel arranged on a flow field plate, wherein a plurality of arc notch unit arrays are arranged on two sides of the cell flow channel, one side of each arc notch unit is an inclined plane, and two adjacent arc notch units on two sides form a channel through the inclined planes; at the entrance of the flow channel, the convection transfer of gas is strengthened transversely through the arc-shaped notch, and the transfer effect to the lower-layer catalyst layer is strengthened through the longitudinal inclined-plane channel, so that the distribution of oxygen in the catalyst layer is more sufficient, the speed of gas in the flow channel is obviously enhanced, the diffusion transfer of gas and the discharge of product water are facilitated, and the performance of the battery is improved.)

1. A proton exchange membrane fuel cell flow passage with double enhanced convection is characterized in that: the flow field plate comprises a battery flow channel arranged on the flow field plate, wherein a plurality of arc notch unit arrays are arranged on two sides of the battery flow channel, one side of each arc notch unit is an inclined plane, and two adjacent arc notch units on two sides form a channel through the inclined planes; at the inlet of the flow channel, the gas is subjected to transverse reinforced convection transfer through the arc-shaped gap, and meanwhile, the transfer effect to the lower-layer catalyst layer is reinforced through the longitudinal inclined-plane channel, so that the distribution of oxygen in the catalyst layer is more sufficient.

2. The dual enhanced convection pem fuel cell flow-channel of claim 1 wherein: the arc-shaped gap units on the two sides of the battery flow channel are distributed and arranged in a staggered manner.

3. The dual enhanced convection pem fuel cell flow-channel of claim 2 wherein: the arc-shaped notch of the arc-shaped notch unit is an elliptic arc-shaped notch.

4. The dual enhanced convection pem fuel cell flow-channel of claim 3, wherein: the semimajor axis of the elliptic arc is 0.1-0.5 mm in length, and the semimajor axis of the minor arc is 0.1-0.6 mm in length.

5. The dual enhanced convection pem fuel cell flow-channel of claim 4 wherein: the length of the line segment between the arc-shaped notch units is consistent with the semimajor axis of the elliptical arc.

6. The dual enhanced convection pem fuel cell flow-channel of claim 5, wherein: the channels are shaped in a sunken triangular array in the longitudinal direction.

7. The dual enhanced convection pem fuel cell flow-channel of claim 6, wherein: the width of the channel is 0.5-2 mm, and the height is 0.5-2 mm.

8. The dual enhanced convection pem fuel cell flow-channel of claim 7 wherein: the period of the sunken triangular array is consistent with that of the elliptical arc array.

9. The dual enhanced convection pem fuel cell flow-channel of claim 8, wherein: the channel is shaped in the longitudinal direction as a sunken rectangle.

10. The dual enhanced convection pem fuel cell flow-channel of claim 1 wherein: the arc-shaped notch of the arc-shaped notch unit is an arc-shaped notch.

Technical Field

The invention belongs to the technical field of proton exchange membrane fuel cells, and particularly relates to a double-convection-enhanced proton exchange membrane fuel cell flow channel.

Background

A Proton Exchange Membrane Fuel Cell (PEMFC) is an energy conversion device that is highly efficient and energy-saving, and converts chemical energy stored therein into electrical energy using hydrogen and air (oxygen) as fuel.

The basic reaction principle of proton exchange membrane fuel cells: hydrogen diffuses from the flow channel to the catalyst layer through the diffusion layer at the anode, and is catalytically dissociated into protons and electrons in the catalyst layer, the protons reach the cathode through the proton exchange membrane, and the electrons reach the cathode through an external circuit; air or oxygen of the cathode reaches the catalytic layer from the flow channel through the diffusion layer, and reacts with protons and electrons on the surface of the catalytic layer under the action of the catalyst to generate water and heat.

In a pem fuel cell, when the anode is hydrogen and the cathode is air, the hydrogen set at the stoichiometric ratio is generally sufficient, and therefore the performance of the pem fuel cell depends to a large extent on the oxygen concentration distribution of the catalytic layer of the cathode. At high current densities, the catalytic layer near the cell exit end tends to suffer from insufficient gas supply with large consumption of oxygen, affecting cell performance. The quality of the battery performance can be judged to a certain extent by detecting the oxygen distribution of the catalyst layer.

The most common flow field type is a straight flow channel, which has many flow field channels parallel to each other, short flow distance, and simple straight flow channel structure. However, the flow field of the direct current channel is easy to be short of oxygen supply at high current density, and the performance of the battery is limited to be further improved. By improving the cell flow channel structure, the oxygen distribution in the cathode catalyst layer can be improved, thereby improving the cell performance.

The invention discloses a proton exchange membrane fuel cell flow passage (CN108550875A), which is characterized in that different numbers of blocks are arranged in a cathode flow passage at intervals, so that the sectional area of the flow passage at the blocks is increased, the speed of gas passing through the flow passage is increased, the effect of easier transfer of the gas to a diffusion layer is achieved, the utilization rate of the gas is improved, and the overall performance level of the cell is improved. But do not show specific improvements to battery performance and lack support for performance data. The invention designs a double-reinforced convection flow channel aiming at the transverse direction and the longitudinal direction of the flow channel, analyzes the concentration and the velocity distribution of gas, is matched with relevant performance comparison, and provides powerful support for effectively improving the battery performance.

Disclosure of Invention

The invention provides a double-convection-enhanced proton exchange membrane fuel cell flow channel, which is designed aiming at the transverse direction and the longitudinal direction of the flow channel, analyzes the concentration and the velocity distribution of gas, is matched with relevant performance comparison, and provides powerful support for effectively improving the cell performance.

The invention is realized by at least one of the following technical schemes.

A proton exchange membrane fuel cell flow channel with double enhanced convection comprises a cell flow channel arranged on a flow field plate, wherein a plurality of arc notch unit arrays are arranged on two sides of the cell flow channel, one side of each arc notch unit is an inclined plane, and two adjacent arc notch units on two sides form a channel through the inclined planes; at the inlet of the flow channel, the gas is subjected to transverse reinforced convection transfer through the arc-shaped gap, and meanwhile, the transfer effect to the lower-layer catalyst layer is reinforced through the longitudinal inclined-plane channel, so that the distribution of oxygen in the catalyst layer is more sufficient.

Preferably, the arc-shaped notch units on two sides of the battery flow channel are arranged in a staggered manner.

Preferably, the arc-shaped notch of the arc-shaped notch unit is an elliptical arc-shaped notch.

Preferably, the semimajor axis of the elliptical arc is 0.1-0.5 mm in length, and the semimajor axis of the elliptical arc is 0.1-0.6 mm in length.

Preferably, the length of the line segment between the arc-shaped notch units is consistent with the semi-major axis of the elliptic arc.

Preferably, the channels are shaped in a sunken triangular array in the longitudinal direction.

Preferably, the width of the channel is 0.5-2 mm, and the height of the channel is 0.5-2 mm.

Preferably, the sunken triangular array period is consistent with the elliptical arc array period.

Preferably, the channel has a shape which is a sunken rectangle in the longitudinal direction.

Preferably, the arc notch of the arc notch unit is an arc notch.

Compared with the prior art, the invention has the following beneficial effects:

compared with the traditional direct current channel, the invention carries out structural design on the flow channel in two layers of the transverse direction and the longitudinal direction. At the inlet of the flow channel, the gas is transversely strengthened by the design of the arc-shaped notch, so that the transverse convection transfer of the gas is strengthened, and the distribution of oxygen in the catalytic layer is more sufficient; in addition, the diffusion and transfer effects of gas to the lower catalyst layer are enhanced under the action of the triangular sinking design in the longitudinal direction, and meanwhile, the speed in the flow channel is increased due to the combined design, so that the gas diffusion and the discharge of product water are facilitated, and the performance of the battery is effectively improved.

Drawings

The features and effects of the present invention are clearly reflected by the detailed description of the following drawings:

FIG. 1 is a schematic structural diagram of a conventional direct flow path PEM fuel cell;

FIG. 2 is a schematic structural diagram of a dual enhanced PEM fuel cell in accordance with example 1 of the present invention;

FIG. 3 is a structural diagram of a dual enhanced PEM fuel cell in accordance with example 2 of the present invention;

FIG. 4 is a structural diagram of a dual enhanced PEM fuel cell in accordance with example 3 of the present invention;

FIG. 5 is a structural diagram of a dual enhanced PEM fuel cell in accordance with example 4 of the present invention;

FIG. 6 is a flow channel velocity profile of a dual enhanced PEM fuel cell structure according to an embodiment of the present invention;

FIG. 7 is a flow velocity profile of a conventional flow channel PEM fuel cell structure;

FIG. 8 is a velocity profile of a flow channel according to example 4 of the present invention;

FIG. 9 is a graph of polarization curves and power densities for a dual enhanced PEM fuel cell structure of an embodiment of the present invention versus a conventional DC path PEM fuel cell structure;

FIG. 10 is a top view of a dual enhanced PEM fuel cell in accordance with an embodiment of the present invention;

FIG. 11 is a front view of a dual enhanced PEM fuel cell according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described in detail and completely with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The components and relative arrangements, numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following examples are given to assist those skilled in the art to understand the present invention in depth, but are not intended to limit the invention in any way. It should be noted that, for those skilled in the art, any variations and modifications can be made without departing from the design concept of the present invention.

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

The flow field of the common direct flow channel has short flow distance and simple structure of the direct flow channel. However, the problem of insufficient oxygen supply is easily caused in the direct-current channel flow field at high current density, and the performance of the battery is further improved. By improving the structure of the cell flow channel, the distribution of oxygen in the cathode catalyst layer can be improved, the electrochemical reaction is promoted, and the performance of the cell is improved.

The proton exchange membrane fuel cell flow channel with double enhanced convection as shown in fig. 11 comprises a cell flow channel arranged on a flow field plate, wherein the upper surface and the lower surface of the cell flow channel are provided with symmetrical notch arrays, two sides of each notch array are provided with a plurality of arc notch unit arrays, the arc notches of the arc notch units are elliptical arc notches, the length of the semimajor axis of the elliptical arc is 0.1-0.5 mm, and the length of the semiminor axis is 0.1-0.6 mm; the arc breach unit dislocation distribution of battery runner both sides is arranged, and one side of every arc breach unit is the inclined plane, and two adjacent arc breach units in both sides pass through the inclined plane and form the passageway, the shape of passageway is sunken triangle-shaped, and the width of passageway is 0.5 ~ 2mm, and the height is 0.5 ~ 2mm, the shape of passageway is not limited to above-mentioned form only.

As shown in fig. 10, the battery flow channel is a wave-like array of arc-shaped notch units (elliptical or arc-shaped notches, etc.) in the transverse direction, one side of each arc-shaped notch unit is an inclined plane, and the arc-shaped notch units are distributed in a triangular (or rectangular, etc.) sinking array in the longitudinal direction, and are designed in a transverse and longitudinal combination manner. At the inlet of the flow channel, the convection transfer of gas is strengthened transversely through the arc-shaped notch unit, and meanwhile, the transfer effect to the lower catalyst layer is strengthened under the action of the triangular sinking design in the longitudinal direction, so that the distribution of oxygen in the catalyst layer is more sufficient, and the performance of the battery is improved.

Fig. 2 to 5 are structural views of a double reinforced flow channel battery according to an embodiment of the present invention (with a hidden cathode plate), and fig. 1 is a structural view of a conventional direct flow channel battery according to a comparative example (with a hidden cathode plate). The flow channel structures of the two poles are the same.

As an embodiment 1, as shown in fig. 2, the arc-shaped notch unit array is two rows of elliptical arc trap arrays, and the elliptical arc units of the two rows of elliptical arc trap arrays are distributed in a staggered manner. The semimajor axis of each elliptical arc unit ellipse is 0.2mm, the semiminor axis is 0.5mm, the length of the bottom edge of the triangle sinking is 0.4mm, the height is 0.8mm, the number of arrays is 36, and the upper and lower elliptical arcs of each arc notch unit are distributed in a staggered manner.

As an embodiment 2, as shown in fig. 3, the arc-shaped notch unit array is two rows of elliptical arc trap arrays, and the elliptical arc units of the two rows of elliptical arc trap arrays are distributed in a staggered manner. The semimajor axis of each elliptical arc unit ellipse is 0.1mm, the semiminor axis is 0.5mm, the length of the bottom edge of the triangle sinking is 0.4mm, the height is 0.6mm, the number of the arrays is 72, and the upper and lower elliptical arcs of each arc notch unit are distributed in a staggered manner.

As embodiment 3, as shown in fig. 4, the arc-shaped notch unit array is two rows of elliptical arc trap arrays, and the elliptical arc units of the two rows of elliptical arc trap arrays are distributed in a staggered manner. The semimajor axis of each elliptical arc unit ellipse is 0.1mm, the semiminor axis is 0.5mm, the length of the bottom edge of the triangle sinking is 0.4mm, the height is 0.9mm, the number of the arrays is 72, and the upper and lower elliptical arcs of each arc notch unit are distributed in a staggered manner.

As a preferred embodiment 4, as shown in fig. 5, the arc-shaped notch unit array is two rows of elliptical arc trap arrays, and the elliptical arc units of the two rows of elliptical arc trap arrays are distributed in a staggered manner. The semimajor axis of each elliptical arc unit ellipse is 0.1mm, the semiminor axis is 0.5mm, the length of the sunken bottom side of the triangle is 0.4mm, the height is 0.8mm, the number of the arrays is 72, and the upper elliptical arc and the lower elliptical arc are distributed in a staggered manner.

The invention adopts a finite element analysis method to carry out numerical simulation analysis on the performances of the embodiment and the comparative example, thereby making evaluation. The software used for finite element analysis was COMSOL. The simulation parameters of the examples and comparative examples were kept in agreement.

As shown in FIG. 6, the oxygen distribution in the catalyst layers in examples 1 to 4 and comparative example was observed. It can be seen that the overall concentration of oxygen in the catalytic layer is greater and the distribution is more uniform in the embodiment 4 of the dual enhanced convection pem fuel cell flow channel of the present invention. The conditions of insufficient gas supply and uneven distribution of reaction gas of the cell catalyst layer are improved, more oxygen promotes the electrochemical reaction process, and the cell performance is improved, in example 3, although the concentration of the oxygen in the catalyst layer at the inlet end is higher, the whole distribution is uneven, so the improvement on the cell performance is not as good as that in example 4.

As shown in fig. 7 and 8, the velocity distributions in the flow channel are shown for example 4 and the comparative example. It can be seen that example 4 of a dual enhanced convection pem fuel cell flow channel of the present invention achieves a significant increase in flow velocity, which helps to promote gas diffusion and product water removal, thereby contributing to improved cell performance,

FIG. 9 is a graph showing the polarization curves and power densities of examples 1 to 4 and comparative example, and it can be seen from the graph thatUnder the same conditions, the power density of the dual reinforced runner in the embodiment 4 can reach 0.58W/cm²Comparison with a proportional straight flow channel (0.47W/cm)²) And the improvement is 23.5%. Thus proving the effectiveness of the flow channel structure of the invention in improving the performance of the battery.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.