Grid type gas-water separator for fuel cell and fuel cell system

Abstract

The invention discloses a grating type gas-water separator for a fuel cell and a fuel cell system, through the arrangement of a flow direction reforming column, after an anode tail row collides with the end face of the flow direction reforming column, the gas flow direction is reformed and changed, and then the gas flow direction is uniformly distributed into gas-water separation flow channels among gratings. The air flow is secondarily reformed into laminar flow by the grating, so that liquid drops are prevented from being rolled away from the wall surface and scattered by turbulent flow; meanwhile, the grid design greatly increases the contact area of liquid drops and a solid wall surface, small liquid drops are adhered to the wall surface and are converged into large liquid drops by utilizing a liquid drop adhesion principle, the temperature of the wall surface is lower than that of gas, so that water vapor is condensed on the wall surface, and the small liquid drops flow and are converged into the large liquid drops on the wall surface under the blowing of gas flow; and the large liquid drops are blown into the water storage cavity under the action of airflow. And through the cooperative use of the flow direction reforming column and the grating, the gas-water separation effect is greatly enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells, and in particular relates to a grid-type gas-water separator for a fuel cell and a fuel cell system. Background Art

[0002] PEM fuel cell, or proton exchange membrane fuel cell, is an energy device that directly converts the chemical energy of hydrogen-oxygen reaction into electrical energy. The reaction directly generates water, has no pollutant emissions, and is highly efficient. At present, the main obstacles to the application of PEM fuel cells in road vehicles are high cost, short life, few hydrogen refueling facilities, high cost of hydrogen storage and transportation, and environmental adaptability.

[0003] To ensure the reaction efficiency, the anode (hydrogen) uses an over-stoichiometric ratio to supply hydrogen. For example, under rated conditions, the anode side stoichiometric ratio is usually around 1.5, and there is still a large amount of unreacted hydrogen in the anode outlet gas. If it is directly discharged, it will cause huge waste and high safety risks. Therefore, the anode outlet gas will be reintroduced into the air intake through an ejector or a circulation pump for recycling. The anode outlet gas is a saturated gas, which not only contains a large amount of water vapor, but also a large amount of liquid water droplets. If the liquid water is not removed and directly introduced into the anode air intake, the droplets will directly block the hydrogen inlet, causing the anode to be short of gas, thereby causing performance degradation and life attenuation.

[0004] In order to remove liquid water droplets in the anode outlet gas, the anode outlet gas will pass through the gas-water separator before being introduced into the anode inlet gas. The main function of the gas-water separator is to separate the liquid water in the gas and then discharge it, while minimizing the pressure drop of the gas passing through the water separator.

[0005] At present, there are three main types of gas-water separators for fuel cells: cyclone type, baffle type and combined type. Cyclone gas-water separators have the characteristics of small size and light weight, but it is difficult to effectively remove the high-speed rotating liquid water, and the separation efficiency is low. Conventional baffle type gas-water separators achieve separation effects through baffles, filters, etc., and have the characteristics of good spatial adaptability and low pressure drop, but also have the problem of low separation efficiency. The combined water separator integrates the advantages of cyclone and baffle types, but its large size is not conducive to spatial layout. At present, all three types of water separators are used in fuel cells.

[0006] For example, the utility model with authorization announcement number CN218867162U discloses a gas-water separator for a hydrogen fuel cell, comprising: a water separator body having a cavity therein, the water separator body being provided with a gas inlet and a gas outlet connected to the cavity; a water separator top cover connected to the upper surface of the water separator body; a water separator water storage tank connected to the lower surface of the water separator body, and the interior of the water separator water storage tank is connected to the cavity; a water separator cyclone, the top of which is connected to the lower surface of the water separator body, and the water separator cyclone is located inside the water separator water storage tank; a nitrogen exhaust solenoid valve connected to the top of the water separator body and close to one side of the water separator top cover; a pressure sensor connected to the top of the water separator body, for measuring the gas pressure of the reflux hydrogen.

[0007] The utility model with authorization announcement number CN219399345U discloses a novel gas-water separator, including a separator main valve body and a valve body cover plate arranged on one side of the separator main valve body and coordinated with the separator main valve body, the separator main valve body is respectively provided with a hydrogen inlet and a hydrogen outlet, an exhaust valve body is arranged on one side of the separator main valve body, an exhaust solenoid valve is connected to one end of the exhaust valve body away from the separator main valve body, a water storage valve is arranged at the bottom of the separator main valve body, a drain valve body is connected to the bottom of the water storage valve, and an electrically heated drain solenoid valve is arranged on one side of the water storage valve.

[0008] If the water separation efficiency of the gas-water separator is low, the return gas from the anode will contain a large amount of liquid water, and the droplets will directly block the hydrogen inlet, causing the anode to be short of gas, thereby causing performance degradation and life reduction. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the present invention provides a grid-type gas-water separator for a fuel cell and a fuel cell system.

[0010] A grid-type gas-water separator for a fuel cell, comprising a gas-water separator body, the gas-water separator body having an inner cavity for gas-water separation, the gas-water separator body also having an air inlet for anode tail discharge into the inner cavity, and a hydrogen outlet for discharging separated hydrogen, an isolation plate being provided at the upper part of the inner cavity, the isolation plate dividing the upper space of the inner cavity into an air inlet cavity and an air outlet cavity, a water storage cavity being provided at the lower part of the inner cavity, and a connecting channel for connecting the air inlet cavity and the air outlet cavity being left between the bottom end of the isolation plate and the water storage cavity;

[0011] The air inlet is located in the air inlet cavity, and the hydrogen outlet is located in the air outlet cavity;

[0012] The air inlet is located on one of the side surfaces of the air-water separator body and is close to the isolation plate. The inner cavity is provided with a flow reforming column at the air inlet. One end surface of the flow reforming column extends toward the air inlet and covers the air inlet. A gap for airflow to enter is left between the end surface of the flow reforming column and the inner wall of the inner cavity.

[0013] The air inlet cavity is also provided with a plurality of grilles at intervals below and to the sides of the air inlet, and an air-water separation flow channel for airflow is formed between adjacent grilles, and a converging channel for airflow is reserved between the bottom of each grille and the bottom surface of the inner cavity.

[0014] Preferably, the air inlet is located at the upper part of the air inlet cavity and close to the isolation plate, the grille includes vertical sections located below the air inlet and arranged vertically in parallel, and the grille on the side away from the air inlet also has a bent section extending upward and bending toward the direction of the air inlet.

[0015] More preferably, the spacing between adjacent grids is 2-6 mm; and the wall thickness of the grid is ≥1 mm.

[0016] More preferably, the flow distribution difference of each gas-water separation flow channel is ≤20%.

[0017] Preferably, the top surface of the water storage chamber has a baffle, and a water inlet is reserved for the separated liquid water to enter the water storage chamber, and the baffle is arranged to be inclined downward toward the water inlet.

[0018] More preferably, the water inlet is located below the isolation plate.

[0019] Preferably, the hydrogen outlet is located at the top of the gas outlet cavity, and the side wall of the gas outlet cavity is provided with a water retaining groove opening vertically downward or obliquely downward.

[0020] Preferably, one side of the gas-water separator body is opened and cooperated with a cover plate, and the air inlet is located on the other side opposite to the cover plate.

[0021] More preferably, each grille is fixed on a mounting plate located on one side of the cover plate, the mounting plate has a positioning mounting column on the side facing the cover plate, and the cover plate is provided with a positioning blind hole for cooperating with the positioning mounting column;

[0022] The flow direction reforming column is provided with a threaded mounting column on the end surface facing the cover plate, and the cover plate is correspondingly provided with a threaded mounting blind hole matched with the threaded mounting column.

[0023] The present invention further provides a fuel cell system, comprising a fuel cell stack and the grid-type gas-water separator, wherein the fuel cell stack has a hydrogen inlet and a hydrogen tail outlet, and the inlet of the grid-type gas-water separator is connected to the hydrogen tail outlet.

[0024] After the anode tail row passes through the grid-type gas-water separator to separate gas and water, the hydrogen re-enters the hydrogen inlet for reuse.

[0025] The grid-type gas-water separator for the fuel cell of the present invention is provided with a flow-direction reforming column, so that the anode tail row entering the inner cavity from the air inlet is reformed and changed in direction after colliding with the end face of the flow-direction reforming column, and the gas flow direction is reformed from directly impacting the side wall of the inner cavity when entering to flowing along the internal space of the inner cavity, and then evenly distributed into the gas-water separation flow channel between the grids. The grid reforms the gas flow into laminar flow for the second time to prevent turbulence from rolling the droplets away from the wall and breaking them up; at the same time, the grid design greatly increases the contact area between the droplets and the solid wall, and uses the droplet adhesion principle to make small droplets adhere to the wall and gather into large droplets, and the wall temperature is lower than the gas temperature to make water vapor condense on the wall, and the small droplets flow and gather into large droplets on the wall under the blowing of the air flow, and the large droplets are blown into the water storage cavity under the action of the air flow. The coordinated use of the flow-direction reforming column and the grid greatly enhances the effect of gas-water separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the three-dimensional structure of the grid type gas-water separator of the present invention.

[0027] Figure 2 It is a three-dimensional structural schematic diagram of the grid type gas-water separator of the present invention from another perspective.

[0028] Figure 3 It is a schematic diagram of the internal structure of the grid type gas-water separator of the present invention.

[0029] Figure 4 for Figure 3 Cross-sectional view along AA direction.

[0030] Figure 5 It is a schematic diagram of the three-dimensional structure of the grid type gas-water separator of the present invention after removing the cover plate.

[0031] Figure numerals: gas-water separator body 1, cover plate 2, air inlet 3, hydrogen outlet 4, isolation plate 5, air inlet chamber 6, air outlet chamber 7, water storage chamber 8, flow to reforming column 9, gap 10, grille 11, baffle 12, water inlet 13, water outlet 14, water retaining groove 15, mounting plate 16, positioning mounting column 17, positioning blind hole 18, threaded mounting column 19, threaded mounting blind hole 20. DETAILED DESCRIPTION

[0032] like Figures 1 to 5As shown, a grid-type gas-water separator for a fuel cell includes a gas-water separator body 1, the gas-water separator body 1 has an inner cavity for gas-water separation, an air inlet 3 for anode tail discharge into the inner cavity, and a hydrogen outlet 4 for discharging separated hydrogen. One side of the gas-water separator body 1 is opened and matched with a cover plate 2, which is fixed to the gas-water separator body 1 by bolts. The air inlet 3 is located on the other side opposite to the cover plate 2.

[0033] The upper part of the inner cavity of the gas-water separator body 1 is provided with a partition plate 5, which divides the upper space of the inner cavity into an air inlet cavity 6 and an air outlet cavity 7. The partition plate 5 is basically arranged to extend in the up-down direction, thereby dividing the upper part of the inner cavity into two left and right chambers, wherein the air inlet cavity 6 occupies a wider width as the main area of ​​gas-water separation, and the air outlet cavity 7 is narrower as an auxiliary area of ​​gas-water separation. Preferably, the volume of the air inlet cavity 6 accounts for ≥70%, and the volume of the air outlet cavity 7 accounts for ≤30%. The air inlet 3 is located in the air inlet cavity 6, and the hydrogen outlet 4 is located in the air outlet cavity 7.

[0034] A water storage chamber 8 is provided at the lower part of the inner cavity of the gas-water separator body 1, and a connecting channel connecting the air inlet chamber 6 and the air outlet chamber 7 is left between the bottom end of the isolation plate 5 and the water storage chamber 8. After the anode tail discharge enters the inner cavity through the air inlet 3, the air and water are separated in the air inlet chamber 6, and then the airflow enters the air outlet chamber 7 from the connecting channel at the bottom of the isolation plate 5.

[0035] The air inlet 3 is located on one of the side surfaces of the gas-water separator body 1 and is close to the isolation plate 5. The inner cavity of the gas-water separator body 1 is provided with a flow-direction reforming column 9 at the air inlet 3. The end surface of one end of the flow-direction reforming column 9 extends toward the air inlet 3 and covers the air inlet 3. A gap 10 for airflow to enter is left between the end surface of one end of the flow-direction reforming column 9 and the inner side wall of the inner cavity. The arrangement of the flow-direction reforming column 9 enables the anode tail row entering the inner cavity from the air inlet 3 to be reformed and changed in direction after colliding with the end surface of the flow-direction reforming column 9, and the airflow direction is reformed from directly impacting the side wall of the inner cavity when entering to flowing along the inner space of the inner cavity.

[0036] The air inlet cavity 6 is also provided with a plurality of grilles 11 below and to the side of the air inlet 3, and an air-water separation flow channel for airflow is formed between adjacent grilles 11, and a converging channel for airflow is left between the bottom of each grille 11 and the bottom surface of the inner cavity.

[0037] The air inlet 3 is located at the upper part of the air inlet cavity 6 and close to the isolation plate 5. The grille 11 includes a vertical section located below the air inlet 3 and arranged vertically in parallel. The grille 11 on the side away from the air inlet 3 also has a bending section extending upward and bending toward the direction of the air inlet 3. Through this design, the airflow rectified to the reforming column 9 is distributed as evenly as possible in the air-water separation flow channel between the grilles 11. The flow distribution difference of each air-water separation flow channel is ≤20%.

[0038] The spacing between adjacent grids 11 is 2-6 mm; the wall thickness of the grid 11 is ≥1 mm. The wall thickness of the grid 11 needs to ensure sufficient strength.

[0039] The water storage chamber 8 is arranged at the bottom of the inner cavity of the entire gas-water separator body 1. In the structure shown in the figure, the water storage chamber 8 is arranged at a corner of the inner cavity. The top surface of the water storage chamber 8 has a baffle 12, and a water inlet 13 is reserved for the separated liquid water to enter the water storage chamber 8. The baffle 12 is arranged to be inclined downward toward the water inlet 13, so as to play a role in guiding the flow. The inclination angle of the baffle 12 should be ≥5° to ensure that the liquid water can flow back to the water storage chamber 8.

[0040] The water inlet 13 is located below the isolation plate 5 and is roughly aligned with the isolation plate 5, so as to conveniently receive the liquid water separated from the air inlet cavity 6 and the air outlet cavity 7. A water outlet 14 is provided at the bottom of the water storage cavity 8 for discharging the separated liquid water.

[0041] The baffle 12 is provided to form an isolated structure in the entire water storage chamber 8, thereby reducing the pressure fluctuation in the gas-water separator caused by drainage. The separated liquid water is blown into the water storage chamber 8 under the action of the airflow and accumulated. The volume of the water storage chamber 8 should be ≥ 2 times the water production per second.

[0042] The hydrogen outlet 4 is located at the top of the outlet cavity 7, and the side wall of the outlet cavity 7 is provided with a water retaining groove 15 with an opening vertically or obliquely downward. In the structure shown in the figure, a vertically downward water retaining groove 15 is respectively provided on the inner cavity side wall on one side and the opposite side of the isolation plate 5.

[0043] The liquid droplets brought up by the airflow usually hang on the wall surface. The water retaining groove 15 blocks the liquid droplets brought by the airflow and gathers them in the water retaining groove 15. After accumulating to a certain extent, they flow back to the water storage chamber 8 under the action of gravity.

[0044] Each grid 11 is fixed on a mounting plate 16 located on one side of the cover plate 2. The mounting plate 16 has a positioning mounting column 17 on the side facing the cover plate 2. In the structure shown in the figure, there are two positioning mounting columns 17. The cover plate 2 is provided with a positioning blind hole 18 for cooperating with the positioning mounting column 17. The flow direction reforming column 9 is provided with a threaded mounting column 19 on the end face facing the cover plate 2, and the cover plate 2 is provided with a threaded mounting blind hole 20 for cooperating with the threaded mounting column 19. During installation, the flow direction reforming column 9 is fixedly installed on the cover plate 2 through the cooperation of the threaded mounting column 19 and the threaded mounting blind hole 20, and the structure of the grid 11 and the mounting plate 16 as a whole is fixed together through the plug-in cooperation of the positioning mounting column 17 and the threaded mounting column 19, and then the whole is installed and the cover plate 2 is covered. The above design method greatly reduces the difficulty of preparing the outer shell of the gas-water separator body, and it is relatively simple to prepare the grid 11 and the flow direction reforming column 9 separately, and the specifications and dimensions can be replaced, and the entire installation process is also relatively simple.

[0045] The present invention further provides a fuel cell system, including a fuel cell stack and the above-mentioned grid-type gas-water separator, the fuel cell stack having a hydrogen inlet and a hydrogen tail outlet, the gas inlet 3 of the grid-type gas-water separator being connected to the hydrogen tail outlet, after the anode tail is separated from the gas and water by the grid-type gas-water separator, the hydrogen re-enters the hydrogen inlet for reuse.

[0046] When the grid-type gas-water separator of the present application is used, the anode tail discharge from the hydrogen tail discharge port of the battery stack enters the gas inlet chamber 6 from the gas inlet 3. After the anode tail discharge from the gas inlet 3 enters the gas inlet chamber 6 and collides with the end face of the reforming column 9, the airflow direction is reformed and changed. It is reformed from directly impacting the side wall of the inner cavity when entering to flowing along the internal space of the inner cavity, and then evenly distributed to enter the gas-water separation flow channel between the grids 11. The grid 11 reforms the airflow into laminar flow for the second time to prevent turbulence from rolling the droplets away from the wall and breaking them up; at the same time, the design of the grid 11 greatly increases the contact area between the droplets and the solid wall surface, and uses the droplet adhesion principle to make small droplets adhere to the wall surface and gather into large droplets, and the wall surface temperature is lower than the gas temperature to make water vapor condense on the wall surface, and the small droplets flow and gather into large droplets under the blowing of the airflow on the wall surface, and the large droplets are blown into the water storage chamber 8 under the action of the airflow. After the anode tail discharge is separated from the gas and water in the air inlet chamber 6, the airflow enters the air outlet chamber 7. After further separation, the airflow is discharged from the upper hydrogen outlet 4. The discharged gas is a hydrogen mixture after separation to remove most of the water, and is reused to enter the fuel cell stack for the second time.

Claims

1. A grid-type gas-water separator for a fuel cell, comprising a gas-water separator body, the gas-water separator body having an inner cavity for gas-water separation, the gas-water separator body also having an air inlet for anode tail discharge into the inner cavity, and a hydrogen outlet for discharging separated hydrogen, characterized in that: The upper part of the inner cavity is provided with an isolation plate, and the isolation plate divides the upper space of the inner cavity into an air inlet cavity and an air outlet cavity. The lower part of the inner cavity is provided with a water storage cavity, and a connecting channel connecting the air inlet cavity and the air outlet cavity is left between the bottom end of the isolation plate and the water storage cavity; The air inlet is located in the air inlet cavity, and the hydrogen outlet is located in the air outlet cavity; The air inlet is located on one of the side surfaces of the air-water separator body and is close to the isolation plate. The inner cavity is provided with a flow reforming column at the air inlet. One end surface of the flow reforming column extends toward the air inlet and covers the air inlet. A gap for airflow to enter is left between the end surface of the flow reforming column and the inner wall of the inner cavity. The air inlet cavity is also provided with a plurality of grilles at intervals below and to the sides of the air inlet, and an air-water separation flow channel for airflow is formed between adjacent grilles, and a converging channel for airflow is reserved between the bottom of each grille and the bottom surface of the inner cavity.

2. The grid-type gas-water separator for a fuel cell according to claim 1, characterized in that: The air inlet is located at the upper part of the air inlet cavity and close to the isolation plate. The grille includes vertical sections located below the air inlet and arranged vertically in parallel. The grille on the side away from the air inlet also has a bent section extending upward and bending toward the direction of the air inlet.

3. The grid type gas-water separator for a fuel cell according to claim 2, characterized in that: The spacing between adjacent grids is 2-6 mm; the wall thickness of the grid is ≥1 mm.

4. The grid-type gas-water separator for a fuel cell according to claim 2, characterized in that: The flow distribution difference of each gas-water separation flow channel is ≤20%.

5. The grid type gas-water separator for a fuel cell according to claim 1, characterized in that: The top surface of the water storage chamber is provided with a baffle plate, and a water inlet is reserved for the separated liquid water to enter the water storage chamber, and the baffle plate is arranged to be inclined downward toward the water inlet.

6. The grid-type gas-water separator for a fuel cell according to claim 5, characterized in that: The water inlet is located below the isolation plate.

7. The grid-type gas-water separator for a fuel cell according to claim 1, characterized in that: The hydrogen outlet is located at the top of the gas outlet cavity, and the side wall of the gas outlet cavity is provided with a water retaining groove with an opening vertically downward or inclined downward.

8. The grid-type gas-water separator for a fuel cell according to claim 1, characterized in that: One side of the gas-water separator body is opened and matched with a cover plate, and the air inlet is located on the other side opposite to the cover plate.

9. The grid-type gas-water separator for a fuel cell according to claim 8, characterized in that: Each grille is fixed on a mounting plate located on one side of the cover plate, the mounting plate has a positioning mounting column on the side facing the cover plate, and the cover plate is provided with a positioning blind hole correspondingly used to cooperate with the positioning mounting column; The flow direction reforming column is provided with a threaded mounting column on the end surface facing the cover plate, and the cover plate is correspondingly provided with a threaded mounting blind hole matched with the threaded mounting column.

10. A fuel cell system, characterized in that: It comprises a battery stack and the grid-type gas-water separator according to any one of claims 1 to 9, wherein the battery stack has a hydrogen inlet and a hydrogen tail outlet, and the inlet of the grid-type gas-water separator is connected to the hydrogen tail outlet. After the anode tail row passes through the grid-type gas-water separator to separate gas and water, the hydrogen re-enters the hydrogen inlet for reuse.

Images