JP2020194685A - Diluter of fuel cell unit - Google Patents

Abstract

To provide a diluter of fuel cell unit which can be mounted in a fuel cell vehicle while saving space, and can prevent infiltration of generated water into an exhaust tube.SOLUTION: A diluter of fuel cell unit includes an enclosure 461, a partition plate 463 for sectioning the inside of the enclosure 461 into a dilution chamber 465 and a vapor liquid separation chamber 467, an intake pipe 71 connected with the lateral wall 469 of the enclosure 461 from the horizontal direction, and taking the gas containing the generated water and air into the vapor liquid separation chamber 467, and an exhaust tube 73 connected with the lateral wall 469 of the enclosure 461 from the horizontal direction, and exhausting the gas containing hydrogen diluted in the dilution chamber 465 from the vapor liquid separation chamber 467. The lateral wall 469 of the enclosure 461 has an inner surface 471 facing the dilution chamber 465, and one end 73a of the exhaust tube 73 is placed in such a state as projecting from the inner surface 471 into the vapor liquid separation chamber 467 farther than one end 71a of the intake pipe 71.SELECTED DRAWING: Figure 2

Description

The present invention relates to a diluter for a fuel cell unit.

Fuel cells generate electricity through a chemical reaction between hydrogen and oxygen. Therefore, in the fuel cell unit including the fuel cell, hydrogen and air (including oxygen) are supplied to the fuel cell. At that time, not all of the hydrogen supplied to the fuel cell is consumed for power generation, and some hydrogen is discharged from the fuel cell as anode off gas. Since the concentration of hydrogen contained in the anode off-gas is too high to be discharged as it is, it is diluted to a predetermined concentration or less with a diluter of the fuel cell unit.

Patent Document 1 describes a water storage tank provided with a tank body for storing water generated by a chemical reaction between hydrogen and oxygen (hereinafter referred to as "produced water") and a dilution chamber provided inside the tank body. Is described. In this water storage tank, the dilution chamber is connected to an intake pipe for taking the cathode off gas into the dilution chamber and an exhaust pipe for exhausting the gas (diluted gas) diluted in the dilution chamber.

JP-A-2017-174665

Generally, in the diluter of the fuel cell unit, hydrogen contained in the anode off gas discharged from the anode of the fuel cell is diluted by the cathode off gas discharged from the cathode of the fuel cell, that is, air, and the diluted gas produced thereby. Is exhausted from the exhaust pipe. In that case, the intake pipe for taking the cathode off gas for dilution into the diluter and the exhaust pipe for exhausting the diluted gas make the fuel cell unit into a fuel cell vehicle (hereinafter, also simply referred to as "vehicle"). It is preferable to connect to the diluter from the horizontal direction for convenience of layout when mounting or for space saving.

However, in the technique described in Patent Document 1, since the intake pipe and the exhaust pipe are connected to the tank body from the vertical direction, the intake pipe and the exhaust pipe are connected when the water storage tank is mounted on the fuel cell vehicle. Extra space is required to convert the orientation of each from vertical to horizontal. Further, even if the intake pipe and the exhaust pipe are connected to the water storage tank from the horizontal direction, the following problems may occur.

The fluid taken into the water storage tank through the intake pipe includes produced water in addition to the cathode off gas. The cathode off gas taken into the water storage tank is air compressed by an air compressor. Therefore, the cathode off gas is vigorously blown from one end of the intake pipe toward the dilution chamber of the water storage tank. At that time, a part of the generated water taken in from the intake pipe together with the air moves from the connection part of the intake pipe to the connection part of the exhaust pipe along the inner surface of the water storage tank due to the influence of the pressure of the air and the surface tension. It may get into the exhaust pipe. In addition, the generated water taken in from the intake pipe may be diffused by the blowout of air and directly enter the exhaust pipe. As a result, the generated water is discharged to the outside of the fuel cell unit together with the diluent gas. When the generated water is discharged to the outside of the fuel cell unit together with the diluting gas in this way, if the fuel cell vehicle on which the fuel cell unit is mounted is an industrial vehicle such as a forklift, the generated water is under the vehicle. It will be washed away and wet the floor of the factory.

The present invention has been made to solve the above problems, and an object of the present invention is a fuel cell unit that can be mounted on a fuel cell vehicle in a space-saving manner and can suppress the infiltration of generated water into an exhaust pipe. To provide a diluter for.

In the present invention, in the diluter of the fuel cell unit, the housing, the partition plate that divides the inside of the housing into the dilution chamber and the gas-liquid separation chamber, and the side wall of the housing are connected from the horizontal direction to generate water. It is provided with an intake pipe that takes in gas containing air into the gas-liquid separation chamber and an exhaust pipe that is connected to the side wall of the housing from the horizontal direction and discharges gas containing hydrogen diluted in the dilution chamber from the gas-liquid separation chamber. The side wall of the housing has an inner surface facing the dilution chamber, and one end of the exhaust pipe is arranged so as to protrude from the inner surface into the gas-liquid separation chamber from one end of the intake pipe.

In the diluter of the fuel cell unit according to the present invention, the partition plate is tilted with respect to the side wall of the housing so that the distance from the inner surface to the partition plate gradually increases from the intake pipe side to the exhaust pipe side. Have been placed.

In the diluter of the fuel cell unit according to the present invention, the gas-liquid separation chamber is provided with a separation hole for separating the generated water.
The separation hole is arranged at a position closer to the exhaust pipe than the intake pipe in the direction parallel to the side wall of the housing.

According to the present invention, it can be mounted on a fuel cell vehicle in a space-saving manner, and the infiltration of generated water into the exhaust pipe can be suppressed.

It is the schematic which shows the structure of the fuel cell system which concerns on embodiment of this invention. It is a schematic plan view which shows the structural example of the diluent which concerns on embodiment of this invention. It is a schematic perspective view which shows the positional relationship between the diluent and the water storage tank which concerns on embodiment of this invention. It is a schematic plan view for demonstrating the function of the diluent which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing a configuration of a fuel cell system according to an embodiment of the present invention.
As shown in FIG. 1, the fuel cell system includes a fuel cell unit 11 and a control unit 12 that controls the fuel cell unit 11.

(Fuel cell unit)
First, the configuration of the fuel cell unit 11 will be described.
The fuel cell unit 11 has a fuel cell 15. The fuel cell 15 has a stack structure in which a plurality of fuel cell cells (not shown) are stacked. A hydrogen supply flow path 16 and an air supply flow path 17 are connected to the fuel cell 15. The hydrogen supply flow path 16 is a flow path through which hydrogen flows when hydrogen stored in the hydrogen tank 30 is supplied to the fuel cell 15. The air supply flow path 17 is a flow path through which air flows when oxygen contained in air in the atmosphere is supplied to the fuel cell 15.

The hydrogen supply flow path 16 is provided with a first pressure sensor 20, an injector 21, and a second pressure sensor 22. In the flow direction of hydrogen flowing through the hydrogen supply flow path 16, the first pressure sensor 20 is arranged on the downstream side of the injector 21, and the second pressure sensor 22 is arranged on the upstream side of the injector 21. The first pressure sensor 20 is a sensor that detects the pressure of hydrogen in the hydrogen supply flow path 16 on the downstream side of the injector 21. The second pressure sensor 22 is a sensor that detects the pressure of hydrogen in the hydrogen supply flow path 16 on the upstream side of the injector 21.

The injector 21 supplies hydrogen to the fuel cell 15. The injector 21 has an injector valve (not shown) built-in, and hydrogen is supplied to the fuel cell 15 by opening and closing the injector valve. The injector 21 is electrically connected to the control unit 12.

Further, the hydrogen supply flow path 16 is provided with a filter 25, a regulator 26, a third pressure sensor 27, a main valve 28, and a temperature sensor 29. The filter 25 captures impurities such as dust. The regulator 26 reduces the pressure of hydrogen supplied from the hydrogen tank 30 via the main valve 28. The third pressure sensor 27 is a sensor that detects the pressure of hydrogen supplied from the hydrogen tank 30 via the main valve 28.

The main valve 28 is a valve that shuts off or allows the supply of hydrogen from the hydrogen tank 30. The main valve 28 shuts off the supply of hydrogen in the closed state and allows the supply of hydrogen in the open state. The opening / closing operation of the main valve 28 is controlled by the control unit 12. The temperature sensor 29 is a sensor that detects the temperature in the hydrogen supply flow path 16 between the main valve 28 and the hydrogen tank 30. The hydrogen tank 30 is a tank for storing hydrogen. A hydrogen supply flow path 31 is connected to the hydrogen tank 30. The hydrogen replenishment flow path 31 is a flow path through which hydrogen replenished from the receptacle 32 to the hydrogen tank 30 flows. Two check valves 33 and 34 are provided in the hydrogen supply flow path 31.

On the other hand, an air compressor 37 is provided in the air supply flow path 17. The air compressor 37 compresses the air sucked from the atmosphere and supplies the compressed air to the fuel cell 15 through the air supply flow path 17.

Further, the circulation flow path 41 and the discharge flow path 42 are connected to the fuel cell 15. The circulation flow path 41 is a flow path for returning hydrogen contained in the anode off gas discharged from the fuel cell 15 to the hydrogen supply flow path 16. The discharge flow path 42 is a flow path for discharging the cathode off gas discharged from the fuel cell 15.

A gas-liquid separator 43 and a hydrogen circulation pump 44 are provided in the circulation flow path 41. The gas-liquid separator 43 separates the anode-off gas discharged from the fuel cell 15 into a gas and a liquid. The hydrogen circulation pump 44 sends hydrogen, which is a gas separated by the gas-liquid separator 43, to the hydrogen supply flow path 16. The hydrogen circulation pump 44 is electrically connected to the control unit 12.

A diluter 46 is provided in the discharge flow path 42. Cathode-off gas discharged from the fuel cell 15 is supplied to the diluter 46. Further, the anode off gas separated by the gas-liquid separator 43 is supplied to the diluter 46 via the exhaust / drain valve 45. The diluter 46 dilutes the hydrogen contained in the anode off gas with the cathode off gas (air) and exhausts the diluted gas generated thereby. An exhaust flow path 47 extends from the diluter 46. The exhaust flow path 47 is a flow path through which the dilution gas exhausted from the diluter 46 flows, and the dilution gas is exhausted to the outside of the fuel cell unit 11 through the exhaust flow path 47.

The water storage tank 48 is connected to the diluter 46. The water storage tank 48 is a tank that receives and stores the generated water from the diluter 46. A water level sensor 49 is provided in the water storage tank 48. The water level sensor 49 is a sensor that detects that the liquid level height of the water stored in the water storage tank 48 has reached a predetermined height. The water in the water storage tank 48 is drained via the drainage coupler 50. The fuel cell unit 11 is configured as described above.

(Control unit)
Next, the configuration of the control unit 12 will be described.
The control unit 12 is composed of a computer including a CPU, RAM, ROM, an interface circuit, and the like. In addition to the injector 21 and the hydrogen circulation pump 44, the control unit 12 includes a first pressure sensor 20, a second pressure sensor 22, a third pressure sensor 27, a main valve 28, a temperature sensor 29, an air compressor 37, and an exhaust / drain valve. The 45 and the water level sensor 49 are electrically connected to each other (see reference numerals A, B, C, D, E, F, G, H in FIG. 1). As a result, the first pressure sensor 20, the second pressure sensor 22, the third pressure sensor 27, the temperature sensor 29, and the water level sensor 49 give their respective detection results to the control unit 12. Further, the injector 21, the hydrogen circulation pump 44, the main valve 28, the air compressor 37, and the exhaust / drain valve 45 operate based on the control commands given from the control unit 12, respectively.

In the fuel cell system having the above configuration, hydrogen supplied to the fuel cell 15 by driving the injector 21 and oxygen contained in the air supplied to the fuel cell 15 by driving the air compressor 37 are contained in the fuel cell 15. Is distributed and supplied to each fuel cell. At that time, hydrogen is supplied to the anode side of the fuel cell, and oxygen is supplied to the cathode side of the fuel cell. As a result, the fuel cell generates electricity by a chemical reaction between hydrogen and oxygen.

FIG. 2 is a schematic plan view showing a configuration example of the diluent according to the embodiment of the present invention. Further, FIG. 3 is a schematic perspective view showing the positional relationship between the diluent and the water storage tank according to the embodiment of the present invention.

As shown in FIGS. 2 and 3, the diluter 46 includes a housing 461. The housing 461 has a rectangular parallelepiped hollow structure. A partition plate 463 is provided inside the housing 461. The partition plate 463 divides the inside of the housing 461 into a dilution chamber 465 and a gas-liquid separation chamber 467. However, the dilution chamber 465 and the gas-liquid separation chamber 467 communicate with each other via a communication portion 466 that forms a predetermined gap. An intake pipe 71 and an exhaust pipe 73 are connected to one side wall 469 of the housing 461. The side wall 469 partitions the gas-liquid separation chamber 467 from the partition plate 463 and has an inner surface 471 facing the gas-liquid separation chamber 467.

Each of the intake pipe 71 and the exhaust pipe 73 is connected to the side wall 469 of the housing 461 from the horizontal direction. That is, the intake pipe 71 and the exhaust pipe 73 are connected to the same side wall 469 in a side-by-side arrangement from the horizontal direction. The intake pipe 71 is a pipe for taking in a gas (cathode-off gas) containing generated water and air into the gas-liquid separation chamber 467. The discharge flow path 42 shown in FIG. 1 is formed by the intake pipe 71. The exhaust pipe 73 is a pipe for discharging the hydrogen-containing gas diluted in the dilution chamber 465, that is, the diluted gas from the gas-liquid separation chamber 467. The exhaust flow path 47 shown in FIG. 1 is formed by the exhaust pipe 73.

One end 71a of the intake pipe 71 opens toward the inside of the gas-liquid separation chamber 467, and one end 73a of the exhaust pipe 73 also opens toward the inside of the gas-liquid separation chamber 467. Further, one end 71a of the intake pipe 71 is arranged at the same position as the inner surface 471 of the side wall 469 without protruding from the inner surface 471. On the other hand, one end 73a of the exhaust pipe 73 is arranged so as to project from the inner surface 471 of the side wall 469 into the gas-liquid separation chamber 467 from the one end 71a of the intake pipe 71. That is, the exhaust pipe 73 penetrates the side wall 469, and one end 73a thereof is arranged in the gas-liquid separation chamber 467. The protruding dimension of the exhaust pipe 73 with reference to the inner surface 471 of the side wall 469 is preferably set to 15 mm or more and 20 mm or less in order to effectively suppress the infiltration of generated water into the exhaust pipe 73.

The partition plate 463 is arranged so as to be inclined with respect to the side wall 469 of the housing 461. Here, if the distance L between the inner surface 471 of the side wall 469 and the partition plate 463 is defined in the X direction (see FIG. 2) orthogonal to the side wall 469, the inclination of the partition plate 463 is such that the distance L is the intake pipe 71. It is set so as to gradually increase from the side toward the exhaust pipe 73 side. Further, a separation hole 75 is formed at the bottom of the gas-liquid separation chamber 467. The separation hole 75 is a hole for separating the generated water taken into the gas-liquid separation chamber 467 through the intake pipe 71 from the cathode off gas. The separation hole 75 is arranged at a position closer to the exhaust pipe 73 than the intake pipe 71 in the Y direction parallel to the side wall 469 of the housing 461.

On the other hand, the gas introduction pipe 77 is connected to the upper wall 473 of the housing 461. The gas introduction pipe 77 is connected to the upper wall 473 of the housing 461 from above in the vertical direction. The gas introduction pipe 77 is a pipe for introducing an anode off gas containing hydrogen into the dilution chamber 465.

The water storage tank 48 is arranged below the diluter 46 as shown in FIG. The water storage tank 48 is a tank for storing generated water. The separation hole 75 described above opens not only at the bottom of the diluter 46 but also at the upper wall of the water storage tank 48. As a result, the generated water taken into the gas-liquid separation chamber 467 is stored in the water storage tank 48 through the separation hole 75. A drainage pipe (not shown) is connected to the water storage tank 48, and a drainage coupler 50 (see FIG. 1) is provided in the drainage pipe. Therefore, when the drainage coupler 50 (see FIG. 1) is opened, the generated water in the water storage tank 48 is drained through the drainage pipe.

Subsequently, the function of the diluter 46 according to the embodiment of the present invention will be described.
First, the anode off gas discharged from the fuel cell 15 is taken into the dilution chamber 465 of the diluter 46 through the gas introduction pipe 77. Further, the cathode off gas and the generated water discharged from the fuel cell 15 are taken into the gas-liquid separation chamber 467 of the diluter 46 through the intake pipe 71. The alternate long and short dash line arrow in FIG. 4 indicates the flow of cathode off gas taken into the gas-liquid separation chamber 467 and the dilution chamber 465 through the intake pipe 71, and the two-dot chain arrow indicates the anode taken into the dilution chamber 465 through the gas introduction pipe 77. The off-gas flow is shown, and the solid arrow indicates the flow of the diluent gas exhausted through the exhaust pipe 73.

The cathode off gas and the generated water taken into the gas-liquid separation chamber 467 are blown out toward the partition plate 463 by the pressure of air, which is the main gas of the cathode off gas. Since the partition plate 463 is inclined with respect to the side wall 469 of the housing 461, the cathode off gas and the generated water diffuse and flow in the gas-liquid separation chamber 467 in the direction indicated by the arrow of the alternate long and short dash line in FIG. At this time, if the separation hole 75 is arranged closer to the intake pipe 71 than the exhaust pipe 73 in the Y direction, most of the generated water is scattered when the generated water scatters due to the momentum of the cathode off gas. It passes above. On the other hand, when the separation hole 75 is arranged closer to the exhaust pipe 73 than the intake pipe 71 in the Y direction, most of the generated water is separated when the generated water scatters due to the momentum of the cathode off gas. It falls near 75 by its own weight. Therefore, the generated water can be efficiently guided to the separation hole 75.

Further, the cathode off gas taken into the gas-liquid separation chamber 467 circulates in the gas-liquid separation chamber 467, and a part of the cathode off gas flows into the dilution chamber 465 through the communication portion 466. Further, in the gas-liquid separation chamber 467, a part of the cathode off gas flows in the direction along the inclination of the partition plate 463 as shown by the arrow of the alternate long and short dash line in FIG. 4, that is, in the direction away from one end 73a of the exhaust pipe 73. As a result, even if the water droplets of the generated water that hit the partition plate 463 and bounce off are scattered toward one end 73a of the exhaust pipe 73, the flow of the cathode off gas flowing in the direction away from one end 73a of the exhaust pipe 73 is in the exhaust pipe 73. It exerts the effect of preventing the infiltration of generated water into the air curtain, that is, the effect of the air curtain. Therefore, the infiltration of generated water into the exhaust pipe 73 due to the bounce of the partition plate 463 is suppressed.

On the other hand, the hydrogen in the anode off-gas taken into the dilution chamber 465 is diluted by the cathode off-gas (air) flowing into the dilution chamber 465 via the communication portion 466 as described above. Further, the anode off-gas flows from the dilution chamber 465 into the gas-liquid separation chamber 467 via the communication portion 466. At this time, by appropriately setting the gap between the communication portions 466, the anode off-gas flows into the gas-liquid separation chamber 467 little by little. The hydrogen in the anode off-gas flowing into the gas-liquid separation chamber 467 in this way is also diluted by the cathode-off gas circulating in the gas-liquid separation chamber 467 as described above, and the diluted gas produced thereby is diluted through the exhaust pipe 73 through the diluter 46. It is discharged to the outside of.

Here, a part of the generated water taken into the gas-liquid separation chamber 467 through the intake pipe 71 is transmitted through the inner surface 471 of the side wall 469 due to the pressure of the air which is the main gas of the anode off gas and the surface tension acting on the generated water itself. It moves from the intake pipe 71 side to the exhaust pipe 73 side. In the present embodiment, one end 73a of the exhaust pipe 73 protrudes from the inner surface 471 of the side wall 469 into the gas-liquid separation chamber 467 from one end 71a of the intake pipe 71. Therefore, the generated water that moves to the exhaust pipe 73 side along the inner surface 471 of the side wall 469 is hindered from moving at the protruding portion of the exhaust pipe 73 by the so-called rat guard principle. Therefore, the infiltration of generated water into the exhaust pipe 73 is suppressed.

As described above, in the diluter 46 according to the embodiment of the present invention, since the intake pipe 71 and the exhaust pipe 73 are connected to the side wall 469 of the housing 461 from the horizontal direction, the fuel cell unit 11 is used as fuel. It facilitates layout when mounted on a battery vehicle. Therefore, the fuel cell unit 11 can be mounted on the fuel cell vehicle in a space-saving manner. Further, since one end 73a of the exhaust pipe 73 is arranged so as to project from the inner surface 471 of the side wall 469 into the gas-liquid separation chamber 467 from the one end 71a of the intake pipe 71, the generated water can enter the exhaust pipe 73. It can be suppressed.

Further, in the embodiment of the present invention, since the partition plate 463 is arranged at an inclination in a predetermined direction with respect to the side wall 469 of the housing 461, hydrogen in the anode off-gas is efficiently distributed in the gas-liquid separation chamber 467. Can be diluted. Further, the exhaust pipe is guided by the partition plate 463 to guide the flow of the cathode off gas (air) taken from the intake pipe 71 into the gas-liquid separation chamber 467 in a predetermined direction, that is, in a direction away from one end (opening) 73a of the exhaust pipe 73. It is possible to more reliably suppress the infiltration of generated water into 73.

Further, in the embodiment of the present invention, since the separation hole 75 is arranged at a position closer to the exhaust pipe 73 than the intake pipe 71 when viewed in the Y direction, the intake pipe 71 is connected to the gas-liquid separation chamber 467. The generated water taken in can be efficiently guided to the separation hole 75.

The technical scope of the present invention is not limited to the above-described embodiment, but also includes a form in which various changes and improvements are made within a range in which a specific effect obtained by the constituent requirements of the invention or a combination thereof can be derived. ..

For example, in the above embodiment, the gas introduction pipe 77 is connected to the housing 461 of the diluter 46 from the vertical direction, but the present invention is not limited to this, and the gas introduction pipe 77 may be connected from the horizontal direction. ..

11 Fuel cell unit, 46 diluter, 71 intake pipe, 71a one end, 73 exhaust pipe, 73a one end, 75 separation hole, 461 housing, 463 partition plate, 465 dilution chamber, 467 gas-liquid separation chamber, 469 side wall, 471 inner surface ..

Claims (3)

In the diluter of the fuel cell unit
With the housing
A partition plate that divides the inside of the housing into a dilution chamber and a gas-liquid separation chamber,
An intake pipe that is connected to the side wall of the housing from the horizontal direction and takes in gas containing generated water and air into the gas-liquid separation chamber.
An exhaust pipe which is connected to the side wall of the housing from the horizontal direction and discharges a gas containing hydrogen diluted in the dilution chamber from the gas-liquid separation chamber is provided.
The side wall of the housing has an inner surface facing the dilution chamber.
A fuel cell unit diluter characterized in that one end of the exhaust pipe is arranged so as to project from the inner surface of the intake pipe into the gas-liquid separation chamber. The partition plate is arranged so as to be inclined with respect to the side wall of the housing so that the distance from the inner surface to the partition plate gradually increases from the intake pipe side to the exhaust pipe side. The diluter for the fuel cell unit according to 1. The gas-liquid separation chamber is provided with a separation hole for separating the generated water.
The diluter for a fuel cell unit according to claim 1 or 2, wherein the separation hole is arranged at a position closer to the exhaust pipe than the intake pipe in a direction parallel to the side wall of the housing.

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