A fuel cell system

Abstract

The application discloses a fuel cell grid type gas-water separator and a fuel cell system. By arranging a flow direction reforming column, after the anode tail gas collides with the end face of the flow direction reforming column, the gas flow direction is reformed, and then the gas flow is evenly distributed into the gas-water separation flow channels between grids. The grid reforms the gas flow into laminar flow to avoid turbulent flow from rolling off the wall surface and scattering; meanwhile, the grid design greatly increases the contact area between the liquid droplets and the solid wall surface, and by using the liquid droplet adhesion principle, small liquid droplets are adhered to the wall surface and gathered into large liquid droplets; the wall surface temperature is lower than the gas temperature, so that water vapor is condensed on the wall surface; under the blowing of the gas flow, the small liquid droplets flow and gather into large liquid droplets on the wall surface, and under the action of the gas flow, the large liquid droplets are blown into the water storage cavity. By cooperation of the flow direction reforming column and the grid, the gas-water separation effect is greatly enhanced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cells, and particularly relates to a grid type gas-water separator for fuel cells and a fuel cell system. BACKGROUND

[0002] PEM fuel cells, i.e. proton exchange membrane fuel cells, are energy devices that directly convert chemical energy of hydrogen-oxygen reactions into electrical energy, and generate water directly without pollutant emissions and with high efficiency. At present, the main obstacles to the application of PEM fuel cells in road vehicles are high cost, short service life, few hydrogen refueling facilities, high cost of hydrogen storage and transportation, and environmental adaptability.

[0003] To ensure the reaction efficiency, the anode (hydrogen) is supplied with hydrogen in an over-proportioned ratio, for example, in the rated operating condition, the anode side is usually in a proportion of about 1.5, and the anode exhaust gas still contains a large amount of unreacted hydrogen. If it is directly discharged, it will cause great waste and high safety risk. Therefore, the anode exhaust gas is introduced into the inlet gas again through an ejector or a circulating pump for recycling. The anode exhaust gas is saturated gas, which contains not only 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 inlet gas, the liquid droplets will directly block the hydrogen inlet, causing the anode to be starved of gas, thereby causing performance degradation and service life attenuation.

[0004] To remove the liquid water droplets in the anode exhaust gas, the anode exhaust gas is introduced into the anode inlet gas after passing through a gas-water separator. 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, the gas-water separator for fuel cells mainly has three types of cyclone type, baffle type and combined type. The cyclone type gas-water separator has the characteristics of small volume and light weight, but the high-speed rotating liquid water is difficult to effectively remove, and the separation efficiency is low. The conventional baffle type gas-water separator separates the liquid water through baffles, filter screens and the like, has the characteristics of good space adaptability and low pressure drop, but also has the problem of low separation efficiency. The combined type water separator integrates the advantages of the cyclone type and the baffle type, but has a large volume which is not conducive to space arrangement. At present, the three types of water separators have been applied in fuel cells.

[0006] For example, the utility model discloses a kind of gas-water separators for hydrogen fuel cell, including: water segregator body, with cavity inside, gas inlet and gas outlet being provided with in water segregator body and being communicated with cavity;Water segregator top cover is connected in the upper surface of water segregator body;Water segregator water storage tank is connected in the lower surface of water segregator body, and the inside of water segregator water storage tank is communicated with cavity;Water segregator cyclone is connected in the lower surface of water segregator body, and water segregator cyclone is located in the inside of water segregator water storage tank;Nitrogen discharge solenoid valve is connected in the top of water segregator body and close to one side of water segregator top cover;Pressure sensor is connected in the top of water segregator body, for measuring the gas pressure of backflow hydrogen.

[0007] The utility model discloses a novel gas-water separator, including separator main valve body and the valve body cover plate being set to one side of separator main valve body and being cooperated with separator main valve body, separator main valve body is provided with hydrogen gas inlet and hydrogen gas outlet respectively, one side of separator main valve body is provided with exhaust valve body, the one end that exhaust valve body is away from separator main valve body is connected with exhaust solenoid valve, the bottom of separator main valve body is provided with water storage valve, the bottom of water storage valve is connected with drain valve body, one side of water storage valve is provided with electric heating drain solenoid valve.

[0008] If the water separation efficiency of gas-water separator is low, the anode back gas contains a large amount of liquid water, and the liquid droplets will directly block the hydrogen gas inlet, causing anode gas shortage, and thus causing performance degradation and service life attenuation. SUMMARY

[0009] The present application provides a grid type gas-water separator for fuel cell and fuel cell system to solve the above problems in the prior art.

[0010] A grid type gas-water separator for fuel cell, comprising a gas-water separator body, the gas-water separator body has an inner cavity for gas-water separation, the gas-water separator body also has a gas inlet for anode tail gas into the inner cavity, and a hydrogen outlet for discharging separated hydrogen, the upper part of the inner cavity has a partition plate, the partition plate separates the upper space of the inner cavity into an inlet cavity and an outlet cavity, the lower part of the inner cavity is provided with a water storage cavity, and a connecting channel is left between the bottom end of the partition plate and the water storage cavity to communicate the inlet cavity and the outlet cavity.

[0011] The gas inlet is located in the inlet cavity, and the hydrogen outlet is located in the outlet cavity.

[0012] The air inlet is located on one side of the gas-water separator body and close to the isolation plate, and the inner cavity is provided with a flow direction reforming column at the air inlet, and an end face of the flow direction reforming column extends to the air inlet and covers the air inlet, and a gap for air flow is left between the end face of the flow direction reforming column and the inner side wall of the inner cavity.

[0013] The air inlet cavity is also provided with a plurality of gratings at the lower side and the side of the air inlet, and a gas-water separation flow channel for air flow is formed between adjacent gratings, and a flow convergence channel for air flow is left between the bottom surface of each grating 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, and the grating comprises a vertical section arranged vertically below the air inlet, and the grating away from the side of the air inlet further has a bending section extending upward and bending towards the direction of the air inlet.

[0015] More preferably, the spacing between adjacent gratings is 2-6 mm, and the wall thickness of the grating is greater than or equal to 1 mm.

[0016] More preferably, the flow distribution difference of each gas-water separation flow channel is less than or equal to 20%.

[0017] Preferably, the top surface of the water storage cavity has a baffle, and a water inlet for the separated liquid water to enter the water storage cavity is left, and the baffle is arranged downwardly inclined to 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 air outlet cavity, and the side wall of the air outlet cavity is provided with an open water retaining groove vertically downward or obliquely downward.

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

[0021] More preferably, each grating is fixed on a mounting plate located on one side of the cover plate, and the mounting plate has a positioning mounting column towards the side of the cover plate, and the cover plate is correspondingly 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 face towards the cover plate, and the cover plate is correspondingly provided with a threaded mounting blind hole for cooperating with the threaded mounting column.

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

[0024] The hydrogen gas re-enters the hydrogen inlet after the anode exhaust gas is separated by the grid type gas-water separator.

[0025] The grid type gas-water separator for fuel cell of the present application makes the anode exhaust gas from the gas inlet into the inner cavity collide with the end face of the flow direction reforming column, and the gas flow direction is reformed, and the gas flow direction is reformed from directly impacting the side wall of the inner cavity to flowing along the inner space of the inner cavity, and then evenly distributed into the gas-water separation flow channel between the grids. The grid re-forms the gas flow into laminar flow to avoid turbulent flow from rolling off the wall and scattering; meanwhile, the grid design greatly increases the contact area between the liquid droplets and the solid wall, and uses the liquid droplet adhesion principle to make small liquid droplets adhere to the wall and coalesce into large liquid droplets, and the wall temperature is lower than the gas temperature to make the water vapor condense on the wall, and the small liquid droplets flow and coalesce into large liquid droplets on the wall under the blowing of the gas flow, and the large liquid droplets are blown into the water storage cavity under the action of the gas flow. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 It is a perspective structural schematic diagram of the grid type gas-water separator of the present application.

[0027] Fig. 2 It is a perspective structural schematic diagram of the grid type gas-water separator of the present application.

[0028] Fig. 3 It is a perspective structural schematic diagram of the grid type gas-water separator of the present application.

[0029] Fig. 4 It is a perspective structural schematic diagram of the grid type gas-water separator of the present application. Fig. 3 It is a sectional view along the A-A direction.

[0030] Fig. 5 It is a perspective structural schematic diagram of the grid type gas-water separator of the present application.

[0031] The grid type gas-water separator of the present application makes the anode exhaust gas from the gas inlet into the inner cavity collide with the end face of the flow direction reforming column, and the gas flow direction is reformed, and the gas flow direction is reformed from directly impacting the side wall of the inner cavity to flowing along the inner space of the inner cavity, and then evenly distributed into the gas-water separation flow channel between the grids. The grid re-forms the gas flow into laminar flow to avoid turbulent flow from rolling off the wall and scattering; meanwhile, the grid design greatly increases the contact area between the liquid droplets and the solid wall, and uses the liquid droplet adhesion principle to make small liquid droplets adhere to the wall and coalesce into large liquid droplets, and the wall temperature is lower than the gas temperature to make the water vapor condense on the wall, and the small liquid droplets flow and coalesce into large liquid droplets on the wall under the blowing of the gas flow, and the large liquid droplets are blown into the water storage cavity under the action of the gas flow. DETAILED DESCRIPTION

[0032] The grid type gas-water separator of the present application makes the anode exhaust gas from the gas inlet into the inner cavity collide with the end face of the flow direction reforming column, and the gas flow direction is reformed, and the gas flow direction is reformed from directly impacting the side wall of the inner cavity to flowing along the inner space of the inner cavity, and then evenly distributed into the gas-water separation flow channel between the grids. Figs. 1-5As shown, a grid type gas-water separator for fuel cell includes a gas-water separator body 1, which has an inner cavity for gas-water separation, and has an inlet 3 for anode tail gas into the inner cavity, and a hydrogen outlet 4 for discharging separated hydrogen. One side of the gas-water separator body 1 is provided with and matched with a cover plate 2, which is fixed to the gas-water separator body 1 by bolts. The 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 separates the upper space of the inner cavity into an inlet cavity 6 and an outlet cavity 7. The partition plate 5 extends in the up-down direction, thereby separating the upper part of the inner cavity into two chambers, wherein the inlet cavity 6 occupies a wider width and serves as a main area for gas-water separation, and the outlet cavity 7 is narrower and serves as an auxiliary area for gas-water separation. Preferably, the volume ratio of the inlet cavity 6 is ≥70%, and the volume ratio of the outlet cavity 7 is ≤30%. The inlet 3 is located in the inlet cavity 6, and the hydrogen outlet 4 is located in the outlet cavity 7.

[0034] The lower part of the inner cavity of the gas-water separator body 1 is provided with a water storage cavity 8. A connecting channel is left between the bottom end of the partition plate 5 and the water storage cavity 8, which connects the inlet cavity 6 and the outlet cavity 7. After the anode tail gas enters the inner cavity through the inlet 3 and is subjected to gas-water separation in the inlet cavity 6, the gas flow enters the outlet cavity 7 through the connecting channel at the bottom of the partition plate 5.

[0035] The inlet 3 is located on one side of the gas-water separator body 1 and close to the partition plate 5. The inner cavity of the gas-water separator body 1 is provided with a flow direction reforming column 9 at the inlet 3. One end face of the flow direction reforming column 9 extends to the inlet 3 and covers the inlet 3. A gap 10 is left between the one end face of the flow direction reforming column 9 and the inner side wall of the inner cavity for the gas flow to enter. The arrangement of the flow direction reforming column 9 makes the anode tail gas entering the inner cavity from the inlet 3 change its flow direction after colliding with the end face of the flow direction reforming column 9, and the gas flow direction is reformed from directly impacting the side wall of the inner cavity to flowing along the inner space of the inner cavity.

[0036] A plurality of grids 11 are further arranged in the inlet cavity 6 below and on the side of the inlet 3. The adjacent grids 11 form gas-water separation flow channels for the gas flow to pass through. A flow converging channel is left between the bottom of each grid 11 and the bottom surface of the inner cavity for the gas flow to pass through.

[0037] The inlet 3 is located in the upper part of the inlet cavity 6 and close to the partition plate 5. The grid 11 includes a vertical section arranged vertically below the inlet 3. The grid 11 away from the side of the inlet 3 further has a bent section extending upward and bending towards the direction of the inlet 3. This design makes the gas flow reformed by the flow direction reforming column 9 as evenly distributed as possible in the gas-water separation flow channels between the grids 11. The flow distribution difference of each gas-water separation flow channel is ≤20%.

[0038] The distance between the adjacent grids 11 is 2-6 mm; the wall thickness of the grid 11 is greater than or equal to 1 mm. The wall thickness of the grid 11 needs to ensure sufficient strength.

[0039] The water storage cavity 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 cavity 8 is arranged at a corner of the inner cavity. The top surface of the water storage cavity 8 has a baffle 12 and is provided with a water inlet 13 for the separated liquid water to enter the water storage cavity 8. The baffle 12 is inclined downward to the water inlet 13, thereby playing a role of flow guide. The inclination angle of the baffle 12 is greater than or equal to 5°, so as to ensure that the liquid water can flow back to the water storage cavity 8.

[0040] The water inlet 13 is located below the isolation plate 5 and is generally aligned with the isolation plate 5, thereby facilitating the reception of the liquid water separated from the air inlet cavity 6 and the air outlet cavity 7. The bottom of the water storage cavity 8 is provided with a water outlet 14 for discharging the separated liquid water.

[0041] The arrangement of the baffle 12 forms an isolated structure for the entire water storage cavity 8, thereby reducing the pressure fluctuation in the gas-water separator caused by water drainage. The separated liquid water is blown into the water storage cavity 8 under the action of the airflow and accumulates in the water storage cavity 8. The volume of the water storage cavity 8 is greater than or equal to twice the amount of water produced per second.

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

[0043] The liquid droplets carried by the airflow are usually hung on the wall surface, the water retaining groove 15 blocks the liquid droplets carried by the airflow and accumulates in the water retaining groove 15. When the accumulation reaches a certain degree, the liquid droplets flow back to the water storage cavity 8 under the action of gravity.

[0044] Each grid 11 is fixed on the mounting plate 16 located on one side of the cover plate 2. The mounting plate 16 has positioning mounting columns 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 correspondingly provided with positioning blind holes 18 for cooperating with the positioning mounting columns 17. The flow direction reforming column 9 is provided with a threaded mounting column 19 on the end surface facing the cover plate 2, and the cover plate 2 is correspondingly 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 fixed and 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 is fixed together through the insertion 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 makes the preparation of the outer shell of the gas-water separator body greatly reduced, while the grid 11 and the flow direction reforming column 9 are separately prepared, which is relatively simple, and the specifications and sizes can be replaced, and the entire installation process is relatively simple.

[0045] The application also provides a fuel cell system, which comprises a stack and the above-mentioned grid gas-water separator, the stack has a hydrogen inlet and a hydrogen tail outlet, the hydrogen tail outlet is connected to the gas inlet 3 of the grid gas-water separator, and the hydrogen tail gas is separated from water by the grid gas-water separator, and then the hydrogen is reused by re-entering the hydrogen inlet.

[0046] When the grid gas-water separator is used, the anode tail gas from the hydrogen tail outlet of the stack enters the gas inlet 3 and then enters the gas inlet cavity 6, and after colliding with the end face of the reforming column 9, the flow direction of the anode tail gas is changed, and the anode tail gas that directly impacts the side wall of the inner cavity when entering is changed to flow along the inner space of the inner cavity, and then is evenly distributed into the gas-water separation flow channels between the grids 11. The grid 11 changes the flow direction of the gas stream for the second time to form a laminar flow to avoid turbulent flow from rolling off the wall and being scattered; meanwhile, the grid 11 is designed to greatly increase the contact area between the liquid droplets and the solid wall, and by using the liquid droplet adhesion principle, small liquid droplets are adhered to the wall and gathered into large liquid droplets, and the wall temperature is lower than the gas temperature, so that the water vapor condenses on the wall, and the small liquid droplets flow and gather into large liquid droplets on the wall under the blowing of the gas stream, and the large liquid droplets are blown into the water storage cavity 8 under the action of the gas stream. After the anode tail gas is separated from water by the gas inlet cavity 6, the gas stream enters the gas outlet cavity 7, is further separated, and then is discharged from the upper hydrogen outlet 4, and the discharged gas is hydrogen mixed gas after most of the water is removed by separation, and the hydrogen mixed gas is reused by re-entering the stack.

Claims

1. A grid-type gas-water separator for a fuel cell, comprising a gas-water separator body having an inner chamber for gas-water separation, the gas-water separator body further having a gas inlet for feeding an anode tail gas to the inner chamber, and a hydrogen outlet for discharging separated hydrogen, characterized in that, The upper part of the inner cavity has a partition plate, which separates the upper space of the inner cavity into an air inlet cavity and an air outlet cavity, and the lower part of the inner cavity is provided with a water storage cavity, and a connecting channel is left between the bottom end of the partition plate and the water storage cavity to connect the air inlet cavity and the air outlet 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 side of the gas-water separator body and close to the partition plate, and the inner cavity is provided with a flow-to-reforming column at the air inlet, and the end face of the flow-to-reforming column extends to the air inlet and covers the air inlet, and a gap is left between the end face of the flow-to-reforming column and the inner side wall of the inner cavity for gas flow to enter; The air inlet cavity is also provided with a plurality of gratings spaced apart below and on the side of the air inlet, and the adjacent gratings form a gas-water separation flow channel for gas flow, and a flow convergence channel is left between the bottom of each grating and the bottom surface of the inner cavity for gas flow. The air inlet is located in the upper part of the air inlet cavity and close to the partition plate, and the grating includes a vertical segment located below the air inlet and arranged vertically in parallel, and the grating away from the side of the air inlet also has a bending segment extending upward and bending towards the direction of the air inlet.

2. The grid-type gas-water separator for fuel cells according to claim 1, wherein The spacing between adjacent gratings is 2-6 mm, and the wall thickness of the grating is ≥1 mm.

3. The grid-type gas-water separator for fuel cells according to claim 1, wherein The flow distribution difference of each gas-water separation flow channel is ≤20%.

4. The grid-type gas-water separator for fuel cells according to claim 1, wherein The top surface of the water storage cavity has a baffle, and a water inlet is left for the separated liquid water to enter the water storage cavity, and the baffle is inclined downward to the water inlet.

5. The grid-type gas-water separator for fuel cells according to claim 4, wherein The water inlet is located below the partition plate.

6. The grid-type gas-water separator for fuel cells according to claim 1, wherein The hydrogen outlet is located at the top of the air outlet cavity, and the side wall of the air outlet cavity is provided with an open water retaining groove vertically downward or obliquely downward.

7. The grid-type gas-water separator for fuel cells according to claim 1, wherein One side of the gas-water separator body is open and cooperatively provided with a cover plate, and the air inlet is located on the other side opposite to the cover plate.

8. The grid-type gas-water separator for fuel cells according to claim 7, wherein Each grating is fixed on a mounting plate located on one side of the cover plate, and the mounting plate has a positioning mounting column on the side facing the cover plate, and the cover plate is correspondingly provided with a positioning blind hole for cooperating with the positioning mounting column; The flow-to-reforming column is provided with a threaded mounting column on the end face facing the cover plate, and the cover plate is correspondingly provided with a threaded mounting blind hole for cooperating with the threaded mounting column.

9. A fuel cell system characterized by comprising: The grid type gas-water separator includes a stack and the grid type gas-water separator of any one of claims 1-8, the stack has a hydrogen inlet and a hydrogen tail discharge port, the air inlet of the grid type gas-water separator is connected to the hydrogen tail discharge port, After the anode tail discharge passes through the grid type gas-water separator for gas-water separation, hydrogen is reused by re-entering the hydrogen inlet.

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