Fuel cell structure

Abstract

The utility model discloses a fuel cell structure and relates to a fuel cell. According to the utility model, a pure mechanical structure is adopted, the principle of airflow collision is utilized, the backflow of hydrogen is hindered, and because the hydrogen is very light and has strong diffusivity, the design of the countercurrent flow channel is adopted, the hydrogen is forced to stay in the specified flow channel, and the hydrogen is discharged into the atmosphere through a dilution method.

Description

Technical Field

[0001] The utility model relates to a fuel cell, in particular to a fuel cell structure. Background Art

[0002] In the fuel cell industry, box purge is a key link to ensure the safe and efficient operation of fuel cells. During the operation of the fuel cell, due to the permeation of the stack, a small amount of hydrogen and moisture will inevitably enter the box. If these accumulated hydrogen and moisture are not discharged in time, they may not only affect the performance of the fuel cell, but also bring safety hazards. Therefore, the design of the box purge system is very important.

[0003] At present, there are two common solutions for the box purge outlet in the fuel cell industry: increasing the airflow and adding a one-way valve. These two solutions have their own advantages and disadvantages, and the appropriate solution needs to be selected according to the actual application scenario and needs.

[0004] 1. Increase airflow plan

[0005] The core idea of ​​the increased airflow solution is to quickly dilute and discharge the hydrogen and moisture in the box by increasing the flow and speed of the purge airflow. The purge airflow usually uses hot air with a temperature of about 70°C, which helps to speed up the evaporation of moisture and the discharge of hydrogen. However, this solution also has some problems.

[0006] Increasing the airflow means that more energy is needed to generate and maintain the airflow, which undoubtedly increases the auxiliary consumption of the fuel cell system. In today's increasingly scarce energy, reducing auxiliary consumption is of great significance to improving the overall efficiency and competitiveness of the fuel cell system.

[0007] 2. Add a one-way valve solution

[0008] The solution of adding a one-way valve is to prevent the water in the tail drain from flowing back into the box by installing a one-way valve between the box and the tail drain manifold. The one-way valve usually uses a small spring-loaded check valve with an opening pressure of less than 2kpa. This solution can effectively prevent the problem of water backflow, but it also has some limitations.

[0009] The one-way valve is prone to freezing in low temperature environments. When the fuel cell system is in a low temperature state, the one-way valve freezes due to the low temperature, causing the one-way valve to be unable to open normally. This may cause the hydrogen and moisture inside the box to be unable to be discharged in time, thus affecting the performance and safety of the fuel cell.

[0010] In view of the limitations of the above prior art, a hydrogen dilution device for box purging is urgently needed. Utility Model Content

[0011] Based on the deficiencies in the prior art, the utility model provides a fuel cell structure, which adopts a purely mechanical structure and utilizes the principle of airflow collision to hinder the reflux of hydrogen.

[0012] The specific technical solutions are as follows:

[0013] The utility model provides a fuel cell structure, comprising a box body and a fuel cell stack arranged in the box body, the box body having a purge inlet and a purge outlet, the purge outlet being used to connect to a tail discharge manifold of the fuel cell, the fuel cell structure also comprising a mechanical one-way valve, the mechanical one-way valve comprising a valve body inlet and a valve body outlet, the valve body inlet being used to connect to the purge outlet of the fuel cell box body, the valve body outlet being used to connect to the tail discharge manifold of the fuel cell, when in use, the valve body inlet is at the top, the valve body outlet is at the bottom, a flow channel is provided between the valve body inlet and the valve body outlet, and the flow channel structure comprises a Tesla valve flow channel structure;

[0014] The Tesla valve flow channel structure includes a plurality of Tesla valve units connected in sequence, wherein the Tesla valve unit includes a main flow channel and an arc-shaped return flow channel, wherein one end of the arc-shaped return flow channel merges into the main flow channel, and the main flow channel merges into the other end of the arc-shaped return flow channel, and the other end of the arc-shaped return flow channel is connected to the main flow channel of another Tesla valve unit.

[0015] Preferably, the number of the Tesla valve units is at least 4.

[0016] Further preferably, the number of the Tesla valve units is 4.

[0017] Since the flow directions of hydrogen and mixed gas are different at the confluence point, the collision of fluids weakens the diffusion capacity of hydrogen and changes the flow direction of hydrogen, so that the refluxed hydrogen is discharged. After four rounds of dilution and discharge of hydrogen, it is completely avoided that the forward flow of hydrogen and the reverse flow of hydrogen converge at the layout position of the hydrogen concentration sensor.

[0018] Specifically, a hydrogen concentration sensor for detecting hydrogen concentration is also provided at the inlet of the valve body.

[0019] Specifically, the valve body outlet is connected to the tail exhaust manifold of the fuel cell using a hose, which can be a silicone hose, a fluoro rubber hose, or an EPDM hose.

[0020] Specifically, the flow channel structure also includes a connecting flow channel structure.

[0021] The connecting flow channel structure includes a first connecting flow channel and a second connecting flow channel;

[0022] One end of the first connecting flow channel is connected to the valve body inlet, and the other end of the first connecting flow channel is connected to the main flow channel in the Tesla valve flow channel structure.

[0023] One end of the second connecting flow channel is connected to the arc-shaped return flow channel in the Tesla valve flow channel structure, and the other end of the second connecting flow channel is connected to the valve body outlet.

[0024] Specifically, the valve body inlet, the first connecting flow channel, the Tesla valve flow channel structure, the second connecting flow channel and the valve body outlet are integrated together.

[0025] Beneficial effects of the utility model:

[0026] The utility model adopts a purely mechanical structure and utilizes the principle of airflow collision to hinder the backflow of hydrogen. Since hydrogen is very light and has a strong diffusion ability, a countercurrent flow channel design is adopted to force the hydrogen to stay in a specified flow channel and discharge the hydrogen into the atmosphere by dilution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the mechanical one-way valve of the utility model;

[0028] Figure 2 It is a rear view of the mechanical one-way valve of the utility model;

[0029] Figure 3 It is a side view of the mechanical one-way valve of the utility model;

[0030] Figure 4 for Figure 3 Middle AA section;

[0031] Figure 5 It is a schematic diagram of the air flow direction in the mechanical one-way valve of the utility model;

[0032] Figure 6 Schematic diagram of the airflow direction in the Tesla valve unit of the present invention;

[0033] Markings in the figure: 1-valve body inlet, 2-valve body outlet, 3-flow channel, 31-Tesla valve flow channel structure, 311-Tesla valve unit, 3111-main flow channel, 3112-arc return flow channel, 32-first connecting flow channel, 33-second connecting flow channel, 4-hydrogen concentration sensor, 5-process plug, 6-mixed gas flow direction, 7-hydrogen diffusion direction, 8-hydrogen gathering point, 9-mixed gas and hydrogen collision point. DETAILED DESCRIPTION

[0034] Example 1

[0035] like Figure 1-4As shown, the utility model provides a fuel cell structure, including a box body and a fuel cell stack arranged in the box body, the box body has a purge inlet and a purge outlet, the purge outlet is used to connect to the tail discharge collector of the fuel cell, the fuel cell structure also includes a mechanical one-way valve, the mechanical one-way valve includes a valve body inlet 1 and a valve body outlet 2, the valve body inlet 1 is used to connect to the purge outlet of the fuel cell box body, the valve body outlet 2 is used to connect to the tail discharge collector of the fuel cell, when in use, the valve body inlet 1 is on the top, the valve body outlet 2 is on the bottom, there is a flow channel 3 between the valve body inlet 1 and the valve body outlet 2, and the flow channel 3 structure includes a Tesla valve flow channel structure 31;

[0036] The Tesla valve channel 31 structure includes a plurality of Tesla valve units 311 connected in sequence, the Tesla valve unit 311 includes a main channel 3111 and an arcuate return channel 3112, one end of the arcuate return channel 3112 merges into the main channel 3111, the main channel 3111 merges into the other end of the arcuate return channel 3112, and the other end of the arcuate return channel 3112 is connected to the main channel 3111 of another Tesla valve unit 311.

[0037] Since the flow directions of hydrogen and mixed gas are different at the confluence, the collision of fluids weakens the diffusion capacity of hydrogen and changes the flow direction of hydrogen, so that the refluxed hydrogen is discharged. After four rounds of dilution and discharge of hydrogen, it is completely avoided that the forward flow of hydrogen and the reverse flow of hydrogen converge at the arrangement position of the hydrogen concentration sensor. Therefore, the number of Tesla valve units 311 is at least 4. Figure 4 In the embodiment, the number of Tesla valve units 311 is 4.

[0038] Specifically, a hydrogen concentration sensor 4 for detecting hydrogen concentration is also provided at the valve body inlet 1 .

[0039] Specifically, the valve body outlet 2 is connected to the tail exhaust manifold of the fuel cell using a hose, which can be a silicone hose, a fluorine hose or an EPDM hose.

[0040] Specifically, the flow channel 3 structure also includes a connecting flow channel structure.

[0041] The connecting channel structure includes a first connecting channel 32 and a second connecting channel 33;

[0042] One end of the first connecting flow channel 32 is connected to the valve body inlet 1, and the other end of the first connecting flow channel 32 is connected to the main flow channel 3111 in the Tesla valve flow channel structure 31.

[0043] One end of the second connecting flow channel 33 is connected to the arc-shaped return flow channel 3112 in the Tesla valve flow channel structure 31 , and the other end of the second connecting flow channel 33 is connected to the valve body outlet 2 .

[0044] There is also a process hole at the connection between the second connecting flow channel 33 and the valve body outlet 2, which is blocked by a process plug 5.

[0045] Specifically, the valve body inlet 1, the first connecting flow channel 32, the Tesla valve flow channel structure 31, the second connecting flow channel 33 and the valve body outlet 2 are integrated together.

[0046] When the utility model is in use, the mixed gas (air, a small amount of hydrogen and water vapor) is blown out of the box purge outlet, enters the mechanical one-way valve through the valve body inlet 1, enters the Tesla valve flow channel structure 31 through the first connecting flow channel 32, and flows in the mechanical one-way valve in the flow direction 6, such as Figure 5 As shown by the solid arrow, the hydrogen discharged from the tail manifold is light and easy to diffuse. The hydrogen floating in the flow channel diffuses upward due to the buoyancy force (hydrogen diffusion direction 7), as shown in Figure 5 As indicated by the dotted arrow;

[0047] The hydrogen returning from the tail discharge manifold diffuses to the mixed gas and hydrogen collision point 9 through the valve body outlet 2 and the second connecting flow channel 33, and then merges and collides with the mixed gas coming out of the main flow channel 3111, which weakens the diffusion capacity of the returning hydrogen and changes the flow direction of the returning hydrogen, forcing the hydrogen to flow downward with the mixed gas, diluting the concentration of the returning hydrogen. Part of the hydrogen is discharged from the flow channel and enters the atmosphere, and part of the hydrogen that is not discharged from the atmosphere floats to 8. Since the structure at 8 is in an arched state, it cannot rise any more and can only change the diffusion mode from the original buoyancy diffusion to diffusion by inertia and concentration gradient, which greatly reduces the diffusion capacity ( Figure 6 ). The diffused hydrogen then merges and collides with the mixed gas, which again weakens the diffusion rate of the hydrogen and changes the flow direction of the hydrogen, forcing the hydrogen to flow downward with the mixed gas. Most of the hydrogen is diluted and discharged from the flow channel into the atmosphere. Only a small part continues to float upward and enters the arc-shaped return channel of another Tesla valve unit. The same principle is used to dilute and discharge the hydrogen. There is almost no reflux hydrogen in the arc-shaped return channel of the top Tesla valve unit. The forward flow of hydrogen and the reverse flow of hydrogen are completely avoided from merging at the arrangement position of the hydrogen concentration sensor 4, thereby avoiding the reverse flow of hydrogen into the box, causing the hydrogen concentration to rise, and causing the hydrogen concentration sensor 4 to alarm or false alarm.

Claims

1. A fuel cell structure, comprising a box and a fuel cell stack arranged in the box, wherein the box has a purge inlet and a purge outlet, and the purge outlet is used to connect to the tail exhaust manifold of the fuel cell, characterized in that: The fuel cell structure further includes a mechanical one-way valve, the mechanical one-way valve includes a valve body inlet and a valve body outlet, the valve body inlet is used to connect to the purge outlet of the fuel cell box, the valve body outlet is used to connect to the tail discharge manifold of the fuel cell, when in use, the valve body inlet is at the top, the valve body outlet is at the bottom, there is a flow channel between the valve body inlet and the valve body outlet, and the flow channel structure includes a Tesla valve flow channel structure; The Tesla valve flow channel structure includes a plurality of Tesla valve units connected in sequence, wherein the Tesla valve unit includes a main flow channel and an arc-shaped return flow channel, wherein one end of the arc-shaped return flow channel merges into the main flow channel, and the main flow channel merges into the other end of the arc-shaped return flow channel, and the other end of the arc-shaped return flow channel is connected to the main flow channel of another Tesla valve unit.

2. The fuel cell structure according to claim 1, characterized in that: The number of the Tesla valve units is at least 4.

3. The fuel cell structure according to claim 2, characterized in that: The number of the Tesla valve units is 4.

4. The fuel cell structure according to claim 1, characterized in that: A hydrogen concentration sensor for detecting hydrogen concentration is also provided at the inlet of the valve body.

5. The fuel cell structure according to claim 1, characterized in that: The valve body outlet is connected to the tail exhaust manifold of the fuel cell by using a hose.

6. The fuel cell structure according to claim 1, characterized in that: The flow channel structure also includes a connecting flow channel structure, The connecting flow channel structure includes a first connecting flow channel and a second connecting flow channel; One end of the first connecting flow channel is connected to the valve body inlet, and the other end of the first connecting flow channel is connected to the main flow channel in the Tesla valve flow channel structure. One end of the second connecting flow channel is connected to the arc-shaped return flow channel in the Tesla valve flow channel structure, and the other end of the second connecting flow channel is connected to the valve body outlet.

7. The fuel cell structure according to claim 6, characterized in that: The valve body inlet, the first connecting flow channel, the Tesla valve flow channel structure, the second connecting flow channel and the valve body outlet are integrated together.

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