CN106816611A - A kind of fuel cell fluids differential flow field plate - Google Patents

Abstract

The invention discloses a polar plate of a fuel cell fluid differential flow field. The polar plate is provided with a gas flow field and a cooling water flow field, wherein the gas flow field includes a gas inlet, a gas outlet, an intake main channel, an exhaust main channel, The air distribution channel, the exhaust distribution channel, the intake section, the diffusion section and the exhaust section, wherein the intake section, the diffusion section and the exhaust section form a diffusion unit. The intake main channel and the exhaust main channel are respectively connected with a plurality of intake sub-runners and exhaust sub-runners, and each intake sub-runner and exhaust sub-runner are respectively connected with two ends of a plurality of diffusion units, and the diffusion unit is in the whole The plates are evenly distributed in the plane, and the diffusion units do not affect each other. During the working process, the gas can be evenly distributed on the surface of the entire gas diffusion layer after two fluid differential actions, and the gas in each diffusion section diffuses to the gas diffusion layer at the same time, and the consumption of gas in each diffusion section will not affect other diffusion sections. It can solve the problem of uneven distribution of fuel cell current density.

Description

A fuel cell fluid differential flow field plate

technical field

The invention belongs to the field of fuel cells, in particular to a fluid differential flow field plate.

Background technique

A fuel cell is a device that directly converts the chemical energy in fuel into electrical energy, and can realize efficient and clean utilization of fuel, so it is one of the effective ways to alleviate the increasingly prominent energy and environmental problems. The battery plate is an important part of the fuel cell, which mainly plays the role of distributing fluid, conducting electricity and supporting the battery structure.

The fluid in the flow field mainly includes the reaction gas hydrogen, oxygen (or air) and the reaction product water (gas or liquid), which has an important impact on the performance of the fuel cell. Insufficient reaction gas will reduce the efficiency of the battery. Uneven distribution of the reaction gas will slow down the local electrochemical reaction rate or even fail. ; The accumulation of reaction product water in the flow field will affect the electrochemical reaction of the catalytic reaction interface and reduce the efficiency of the fuel cell.

The basic flow field forms include serpentine runners, parallel runners, parallel serpentine runners, interdigitated runners, spiral runners and grid runners. The serpentine flow channel has only one flow channel from the inlet to the outlet on the flow field plate, which can quickly discharge the liquid water generated by the fuel cell, but for a flow field plate with a large area, the reaction pressure drop will be too large due to the too long flow channel , Insufficient supply of reaction gas in the back section of the flow channel, etc.; the parallel flow channel has a large number of parallel flow channels, and the flow channel resistance is small, but due to the slow flow rate of the gas, the water is not easy to discharge, and it is easy to cause the electrode to be flooded; The design of the serpentine flow channel covers the design of the serpentine flow channel and the parallel flow channel, which has greater flexibility, and the length and number of the flow channels and the size of the flow channels can be adjusted; the interdigitated flow channels are discontinuous, and the fluid is Forced to pass through the diffusion layer to improve the utilization of the electrode, but the resistance of the diffusion layer is large, the pressure drop of the fluid is large, and the catalyst layer may be damaged; the spiral flow channel is similar to the serpentine flow channel, and the drainage capacity is better, but the pressure drop is lower Large, the flow is prone to short circuit; the grid flow field is a method of abandoning the flow channel, usually the barriers are regularly arranged between the fluid inlet and outlet, so that the fluid flows around the pores between the barriers, this flow The fluid flow rate in the channel is low, the drainage capacity is poor, the fluid flow uniformity is poor, and it is easy to flood at the corners.

The current plate flow field adopts a similar method. The entire flow channel is parallel to the plane of the plate. The reaction gas starts from the inlet and flows along the flow channel in the plate surface to the outlet. The fluid flow path is relatively long. This form of flow channel has obvious disadvantages. The fluid is continuously consumed during the flow process, causing the reaction gas near the exit to be thinner than the reaction gas at the entrance. The electrochemical reaction rate in the plane is different, and the current density distribution is uneven, which affects the performance of the battery. ; In addition, for the side of the plate where the reaction product water is generated, water molecules will enter the flow channel of the plate, the closer to the outlet, the higher the water molecule content, and the accumulation of water molecules in the flow field will affect the electric current of the catalytic reaction interface. The chemical reaction further increases the difference in the electrochemical reaction rate in the plane, affects the uniformity of the current density distribution, and reduces the efficiency of the fuel cell.

Contents of the invention

The purpose of the present invention is to solve the disadvantage of poor fluid distribution in the existing fuel cell polar plate flow channel, and provide a fluid differential flow field polar plate which can make the fluid distribution in each part of the polar plate plane uniform and has good drainage performance.

A fuel cell fluid differential flow field pole plate of the present invention is composed of a flow channel plate and a cover plate, and the flow channel plate is provided with a gas flow field and a cooling water flow field; the gas flow field includes a gas inlet, a gas outlet, an inlet The air main channel, the exhaust main channel, the intake runner, the exhaust runner, the intake section, the diffusion section and the exhaust section, wherein the intake section, the diffusion section and the exhaust section form a diffusion unit; the gas inlet and the gas The outlet is a cylindrical hole, which is perpendicular to the plane of the flow channel plate and arranged diagonally; the front and back of the flow channel plate are provided with parallel intake main channels and exhaust main channels, and the intake main channels and exhaust main channels Two grooves are formed, which are respectively connected to the gas inlet and the gas outlet; the back of the flow channel plate is provided with the same number of intake runners and exhaust runners parallel to each other and distributed at intervals, forming multiple grooves, The intake runners and exhaust runners are vertically arranged with the intake main runners and the exhaust main runners, and the intake runners are connected with the intake main runners, and the exhaust runners are connected with the exhaust main runners; The position between the air main channel and the exhaust main channel is provided with multi-row and multi-row diffusion sections parallel to the intake main channel and the exhaust main channel. The number of grooves formed by each row of diffusion sections is located between the projections of the corresponding intake runners and exhaust runners on the front of the plate, and its length is equal to that between the corresponding intake runners and exhaust runners distance; the two ends of each diffusion section communicate with the intake runner and the exhaust runner respectively through the inlet section and the exhaust section perpendicular to the plane of the runner plate; the cooling water flow field includes the cooling water inlet, the cooling Water outlet, water inlet main channel, drainage main channel and cooling water working channel; cooling water inlet and cooling water outlet are cylindrical holes, arranged diagonally perpendicular to the flow channel plate plane, and cooling water inlet and cooling water outlet Compared with the gas inlet and gas outlet, it is closer to the edge of the flow channel plate; the water inlet main channel and the discharge main channel are arranged on the back of the flow channel plate, parallel to the intake main channel and the exhaust main channel, and respectively connected to the cooling water The inlet is connected to the cooling water outlet; the cooling water working channel is set between the corresponding intake runners and exhaust runners on the back of the runner plate, parallel to the intake runners and exhaust runners and has the same number, each The two ends of the cooling water working flow channel are respectively connected with the main water inlet channel and the main drainage channel; the gas inlet, gas outlet, cooling water inlet and cooling water outlet are set at the corresponding positions of the cover plate and the flow channel plate, and the cover plate is set on the flow channel. the back of the board.

The present invention is a fuel cell fluid differential flow field polar plate, the cross-sectional area of each section of the diffusion unit is the same, and is smaller than the cross-sectional area of the intake flow channel and the exhaust flow channel, and the cross-sectional area of the intake flow channel and the exhaust flow channel. The area is smaller than the cross-sectional area of the intake main channel and the exhaust main channel.

The invention relates to a fuel cell fluid differential flow field plate, the diffusion section of the diffusion unit is a rectangular groove, the width and depth of the groove range from 0.3mm to 1mm, and the distance between adjacent diffusion sections in the same row is less than or equal to the groove The distance between two adjacent columns of diffusion segments is less than or equal to the width of the groove.

The invention relates to a fuel cell fluid differential flow field pole plate, the communication between the intake main channel and the intake sub-channel and the communication between the exhaust main channel and the exhaust sub-channel are in an overlapping manner, and the intake main channel and the exhaust The main channel is not in the same plane as the intake runner and the exhaust runner.

The invention relates to a fuel cell fluid differential flow field pole plate, wherein the groove edge of the diffusion section is rounded.

The invention relates to a fuel cell fluid differential flow field pole plate. The bottom surface of the groove of the diffusion section can be set as an arc surface, which is convenient for processing and cleaning.

The invention relates to a fuel cell fluid differential flow field pole plate. The material of the flow channel plate and the cover plate is conductive material, and the solid part of the cover plate and the back of the flow channel plate is fixed and sealed by bonding and sealing material.

The present invention is a fuel cell fluid differential flow field pole plate. During the working process, the reaction gas enters the intake main channel from the gas inlet. Due to the overlapping communication mode between the intake main channel and the intake branch channel, the gas preferentially fills the entire intake air channel. The main channel makes the gas flow into each intake sub-channel similar after fluid differentiation; the gas entering each intake sub-channel enters the parallel diffusion units after fluid differentiation again, and there is no mutual influence between different diffusion units, ensuring flow The reactant gas flows through different diffusion units are similar. The gas in the diffusion unit enters the diffusion section through the intake section, part of the gas enters the gas diffusion layer of the fuel cell in the diffusion section, and the remaining gas enters the exhaust sub-channel through the exhaust section. The channels are collected and discharged from the gas outlet.

As can be seen from the above technical solutions, the beneficial effects of the present invention are:

1. After two times of fluid differentiation, the gas can be evenly distributed on the surface of the entire gas diffusion layer. The gas in each diffusion section diffuses to the gas diffusion layer at the same time, and the consumption of gas in each diffusion section will not affect other diffusion sections. , can fundamentally solve the problem of uneven distribution of fuel cell current density.

2. For the plate with water generation, the water mainly enters each diffusion section from the gas diffusion layer. Since the diffusion section is very short, the generated water will not accumulate, and will quickly enter the exhaust section from the diffusion section, and pass through the exhaust flow channel And the exhaust main channel is finally discharged to the outlet, and the drainage effect is better for the curved diffusion section. Since the generated moisture will not flow through other diffusion sections and will not accumulate in the diffusion section, it will not affect the electrochemical reaction at the catalytic reaction interface and improve battery performance.

Description of drawings

Fig. 1 is a schematic structural diagram of a fuel cell fluid differential flow field plate of the present invention;

Fig. 2 is a schematic cross-sectional view of Fig. 1;

Fig. 3 is a schematic diagram of the front structure of the flow channel plate of a fuel cell fluid differential flow field plate of the present invention;

Fig. 4 is a schematic diagram of the back structure of the flow channel plate of a fuel cell fluid differential flow field plate of the present invention;

Fig. 5 is a flow field structure schematic diagram of a fuel cell fluid differential flow field plate of the present invention;

Fig. 6 is a flow field projection view of a fuel cell fluid differential flow field plate of the present invention;

Fig. 7 is a schematic diagram of the cooling water flow field structure of a fuel cell fluid differential flow field plate of the present invention;

Fig. 8 is a structural schematic diagram of a cover plate of a fuel cell fluid differential flow field plate according to the present invention;

Fig. 9 is a schematic cross-sectional view of a polar plate of an arc-shaped diffusion section of a fuel cell fluid differential flow field polar plate according to the present invention.

In the figure: 1. polar plate, 2. gas inlet, 3. gas outlet, 4. intake main channel, 5. exhaust main channel, 6. intake sub-runner, 7. exhaust sub-runner, 8. diffusion unit , 9. Cooling water inlet, 10. Cooling water outlet, 11. Water inlet main channel, 12. Drain main channel, 13. Cooling water working channel, 81. Air intake section, 82. Diffusion section, 83. Exhaust section , 84. curved surface, 101. runner plate, 102. cover plate.

detailed description:

A fuel cell fluid differential flow field plate of the present invention is composed of a flow channel plate 101 and a cover plate 102, as shown in Figures 1 and 2, the flow channel plate 101 is provided with a gas flow field and a cooling water flow field; The gas flow field includes a gas inlet 2, a gas outlet 3, an intake main channel 4, an exhaust main channel 5, an intake sub-channel 6, an exhaust sub-channel 7, an intake section 81, a diffusion section 82 and an exhaust section 83 , wherein the air inlet section 81, the diffuser section 82 and the exhaust section 83 constitute the diffuser unit 8; the gas inlet 2 and the gas outlet 3 are circular holes, which are perpendicular to the plane of the flow channel plate 101 and arranged diagonally, as shown in the figure 3; the front sides of the flow channel plate 101 are provided with parallel intake main channels 4 and exhaust main channels 5, and the intake main channels 4 and exhaust main channels 5 form two grooves, which are connected to the gas inlet respectively. 2 communicates with the gas outlet 3; the back of the flow channel plate 101 is provided with a plurality of intake runners 6 and exhaust runners 7 of the same number parallel to each other and distributed at intervals, forming a plurality of grooves, the intake runners 6 and the exhaust runners 7 The exhaust sub-runner 7 is vertically arranged with the intake main channel 4 and the exhaust main channel 5, and the intake sub-runner 6 communicates with the intake main channel 4, and the exhaust sub-runner 7 communicates with the exhaust main channel 5; as shown in Fig. 4 - Figure 6. The position between the intake main channel 4 and the exhaust main channel 5 on the front of the runner plate 101 is provided with multi-row multi-column diffusion sections 82 parallel to the intake main channel 4 and the exhaust main channel 5, and the number of columns of the diffusion sections 82 is Equal to the number of intake runners 6 and exhaust runners 7, the plurality of grooves formed by each diffuser section 82 are located between the projections of the corresponding intake runners 6 and exhaust runners 7 on the front of the pole plate 1 , and its length is equal to the distance between the corresponding intake runners 6 and exhaust runners 7; the two ends of each diffusion section 82 respectively pass through the intake section 81 and the exhaust section 83 perpendicular to the plane of the runner plate 101 It communicates with the intake sub-channel 6 and the exhaust sub-channel 7; the cooling water flow field includes a cooling water inlet 9, a cooling water outlet 10, an inlet main channel 11, a drainage main channel 12 and a cooling water working channel 13; The cooling water inlet 9 and the cooling water outlet 10 are circular holes, arranged diagonally perpendicular to the plane of the flow channel plate 101, and the cooling water inlet 9 and the cooling water outlet 10 are closer to the flow channel than the gas inlet 2 and the gas outlet 3 The edge of the channel plate 101; the water inlet main channel 11 and the discharge main channel 12 are arranged on the back side of the channel plate 101, and are parallel to the intake main channel 4 and the exhaust main channel 5, and are respectively connected to the cooling water inlet 9 and the cooling water The outlet 10 is connected; the cooling water working flow channel 13 is arranged between the corresponding inlet runner 6 and the exhaust runner 7 on the back of the runner plate 101, and is parallel to the intake runner 6 and the exhaust runner 7 and has the same number , the two ends of each cooling water working channel 13 communicate with the main water inlet channel 11 and the main drainage channel 12 respectively, as shown in Figure 7; the corresponding positions of the cover plate 102 and the channel plate 101 are provided with gas inlet 2, gas The outlet 3 , the cooling water inlet 9 and the cooling water outlet 10 , as shown in FIG. 8 , the cover plate 102 is arranged on the back of the flow channel plate 101 .

The fuel cell fluid differential flow field polar plate of the present invention, the cross-sectional area of each section of the diffusion unit 8 is the same, and is smaller than the cross-sectional area of the intake sub-channel 6 and the exhaust sub-channel 7, the intake sub-channel 6 and the exhaust sub-channel The cross-sectional area of the sub-runner 7 is smaller than the cross-sectional areas of the intake main passage 4 and the exhaust main passage 5 .

A fuel cell fluid differential flow field plate of the present invention, the diffusion section 82 of the diffusion unit 8 is a rectangular groove, the width and depth of the groove range from 0.3mm to 1mm, and the distance between the adjacent diffusion sections 82 in the same row is less than or is equal to the width of the groove, and the distance between two adjacent columns of diffusion segments 82 is less than or equal to the width of the groove.

The fuel cell fluid differential flow field pole plate of the present invention, the communication between the intake main channel 4 and the intake sub-channel 6 and the communication between the exhaust main channel 5 and the exhaust sub-channel 7 are in an overlapping manner, and the intake main channel Channel 4 and exhaust main channel 5 are not in the same plane as intake sub-channel 6 and exhaust sub-channel 7 .

In the fuel cell fluid differential flow field plate of the present invention, the groove edge of the diffusion section 82 is rounded.

In the fuel cell fluid differential flow field plate of the present invention, the groove bottom surface of the diffusion section 82 can be set as an arc-shaped surface 84, as shown in FIG. 9 .

The fuel cell fluid differential flow field plate of the present invention, the material of the flow channel plate 101 and the cover plate 102 is conductive material, and the solid part of the cover plate 102 and the back of the flow channel plate 101 is fixed and sealed by bonding and sealing material.

The present invention will be described below by taking a fuel cell fluid differential flow field plate of the present invention as an example:

For a fuel cell with a cross-sectional size of the gas diffusion layer of 20 mm×20 mm, the cross-sectional size of the flow channel plate 101 and the cover plate 102 constituting the pole plate 1 is designed to be 30 mm×30 mm, the thickness of the cover plate 102 is 0.7 mm, and the thickness of the flow channel plate 101 is 1.8 mm . The grooves of the diffusion sections 82 located on the front of the flow channel plate 101 are 0.5mm deep, and are evenly arranged in a square position of 20mm×20mm. The width of each diffusion section 82 is 0.5mm, and the interval between adjacent diffusion sections 82 in the same row is 0.5mm, and the number of diffusion sections 82 in each row of diffusion sections 82 is 20; the length of the diffusion section 82 is 3mm, adjacent The distance between two columns of diffusion segments 82 is 0.5mm, and the number of columns of diffusion segments 82 is 6; the diffusion segments 82 located at the peripheral edges of the square may partially exceed the edge of the square. The slot width of the intake runner 6 and the exhaust runner 7 located on the back of the flow channel plate 101 is 0.5 mm, the slot depth is 0.8 mm, and passes through the intake section 81 and the exhaust section with a cross-sectional size of 0.5 mm×0.5 mm. 83 communicates with the diffuser section 82; the intake sub-channel 6 extends to the intake main channel 4 along the length direction to one side, and the exhaust sub-channel 7 extends to the exhaust main channel 5 along the length direction to the other side. The intake main channel 4 and the exhaust main channel 5 located on the front of the runner plate 101 have a groove depth of 1 mm and a groove width of 1.2 mm, which overlap and communicate with the intake sub-runner 6 and the exhaust sub-runner 7 respectively. The gas inlet 2 and the gas outlet 3 communicate with the intake main channel 4 and the exhaust main channel 5 respectively, and have a cross-sectional diameter of 2 mm. The cooling water flow field located on the back of the flow channel plate 101 has a depth of 0.5 mm for each channel groove, wherein the cooling water working channel 13 has a groove width of 1 mm, and the groove width of the water inlet main channel 11 and the drainage main channel 12 is 2 mm; the cooling water The cross-sectional diameter of the inlet 9 and the cooling water outlet 10 is 3 mm.

During the working process, the reaction gas enters the intake main channel 4 from the gas inlet 2. Due to the overlapping connection between the intake main channel 4 and the intake sub-channel 6, the gas fills the entire intake main channel 4 first, so that the fluid enters after differentiation. The gas flow rate of each intake sub-channel 6 is similar; the gas entering each intake sub-channel 6 enters the parallel diffusion units 8 after fluid differentiation again, and there is no mutual influence between different diffusion units 8, ensuring that the gas flows through different diffusion units The reaction gas flow rate in 8 is similar. The gas in the diffusion unit 8 enters the diffusion section 82 through the intake section 81, part of the gas enters the gas diffusion layer of the fuel cell at the diffusion section 82, and the remaining gas enters the exhaust sub-channel 7 through the exhaust section 83, and each exhaust sub-channel 7 The exhausted gas is collected in the main exhaust channel 5 and discharged from the gas outlet 3. It can be seen that this structural design allows the gas to be evenly distributed on the entire surface of the gas diffusion layer after two fluid differential actions, and the gas in each diffusion section 82 diffuses to the gas diffusion layer at the same time, and the gas in each diffusion section 82 The consumption will not affect other diffusion sections 82, which can fundamentally solve the problem of uneven distribution of the current density of the fuel cell.

In addition, for the pole plate 1 with water generated, the water mainly enters the diffusion section 82 of each diffusion unit 8 from the gas diffusion layer. Since the diffusion section 82 is very short, the generated water will not accumulate and will quickly enter the exhaust from the diffusion section 82. The gas section 83 is finally discharged to the outlet through the exhaust sub-flow channel 7 and the main exhaust channel 5. For the arc-shaped diffuser section 82, the drainage effect is better. Since the generated moisture will not flow through other diffusion sections 82 and will not accumulate in the diffusion section 82, it will not affect the electrochemical reaction at the catalytic reaction interface and improve battery performance.

Claims (7)

1. a kind of fuel cell fluids differential flow field plate, it is characterised in that：It is made up of runner plate and cover plate, is set on runner plate There are gas flowfield and cooling water flow；The gas flowfield includes gas access, gas vent, air inlet sprue, exhaust main flow Road, air inlet runner, bypassing exhaust road, air inlet section, diffuser and exhaust section, wherein air inlet section, diffuser and exhaust section composition Diffusion unit；Gas access is cylindrical hole with gas vent, is each perpendicular to runner plate plane and is arranged in diagonal；Runner The front and back of plate is provided with parallel air inlet sprue and exhaust sprue, and air inlet sprue and exhaust sprue form two Bar groove, and respectively with gas access and gas outlet；The back side of runner plate is provided with the phase for being parallel to each other, being spaced apart With a plurality of air inlet runner and bypassing exhaust road of quantity, a plurality of groove, air inlet runner and bypassing exhaust road and air inlet are formed Sprue and exhaust sprue are arranged vertically, and air inlet runner connect with air inlet sprue, bypassing exhaust road and are vented main flow Road is connected；Position between runner plate frontal inlet sprue and exhaust sprue is provided with parallel to air inlet sprue and exhaust Multiple rows of multiple row diffuser of sprue, the columns of diffuser is equal to the number in air inlet runner and bypassing exhaust road, each column diffusion The a plurality of groove that section is formed is located at corresponding air inlet runner and bypassing exhaust road between the positive projection of pole plate, and its length Equal to the distance between corresponding air inlet runner and bypassing exhaust road；Every two ends of diffuser are respectively by perpendicular to runner The air inlet section and exhaust section of plate plane are connected with air inlet runner and bypassing exhaust road；The cooling water flow enters including cooling water Mouth, coolant outlet, water inlet sprue, draining sprue and cooling water platform flow channel；Cooling water inlet and coolant outlet are Cylindrical hole, arranges perpendicular to runner plate plane in diagonal, and cooling water inlet and coolant outlet are gentle with gas access Body outlet is compared closer to the edge of runner plate；Water inlet sprue and draining sprue are arranged at the back side of runner plate, and parallel In air inlet sprue and exhaust sprue, and connect with cooling water inlet and coolant outlet respectively；Cooling water platform flow channel sets Position between the corresponding air inlet runner of runner back and bypassing exhaust road is placed in, it is flat with air inlet runner and bypassing exhaust road Go and quantity is identical, every two ends of cooling water platform flow channel connect with water inlet sprue and draining sprue respectively；Cover plate with The corresponding position of runner plate sets gas access, gas vent, cooling water inlet and coolant outlet, and cover plate is arranged at runner The back side of plate.

2. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：The diffusion unit Each section of sectional area is identical, and less than air inlet runner and the sectional area in bypassing exhaust road, air inlet runner and bypassing exhaust road Sectional area less than air inlet sprue and exhaust sprue sectional area.

3. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：The diffusion unit Diffuser be rectangular channel, the width and depth bounds of groove are all 0.3mm to 1mm, and the distance between adjacent diffuser of same column is small In or equal to groove width, the width of the distance between adjacent two row diffuser less than or equal to groove.

4. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：The air inlet main flow Road is overlapping mode, air inlet sprue and row with the connection of air inlet runner and exhaust sprue and the connection in bypassing exhaust road Gas sprue and air inlet runner and bypassing exhaust road are not in the same plane.

5. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：The diffuser Groove edge carries out rounding treatment.

6. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：The diffuser Groove bottom could be arranged to arcwall face.

7. a kind of fuel cell fluids differential flow field plate according to claim 1, it is characterised in that：Runner plate and cover plate Material be conductive material, the entity part of the cover plate and runner back is fixed sealing by adhering and sealing material.