JP2009123518A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system without unnecessary residue water remaining inside, through promotion of drainage inside an ion-exchange filter fitted to a gas liquid separator. <P>SOLUTION: The fuel cell system 1 includes a fuel cell stack 10, a gas liquid separator 20, a dilution unit 16, a hydrogen supply valve 11, a pump 13 as well as a motor 12 for the pump, a drain valve controller 15, and a fuel cell control device 14. From the fuel cell stack 10, offgas including unreacted hydrogen gas and reaction water flows into an offgas flow channel 42 to be guided to the gas liquid separator 20. The gas liquid separator 20 includes an ion-exchange filter 30 equipped with a guide member on a bottom face for promoting drop of droplets, and the reaction water is guided from a drain flow channel 44 to the dilution unit 16 to be drained therefrom 16, and discharged into the air. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system mounted on a vehicle and having a gas-liquid separator in an exhaust gas passage through which off-gas from the fuel cell flows.

  Fuel cells are attracting attention as power sources for electric vehicles. In this fuel cell, an ion exchangeable electrolyte membrane, a hydrogen electrode disposed on one surface of the electrolyte membrane, an oxygen electrode disposed on the other surface, and hydrogen gas and air are supplied to each electrode. And a separator that forms the flow path, and a plurality of the cells are stacked to form a fuel cell stack.

  A fuel cell system including such a fuel cell stack generates power from hydrogen as fuel and oxygen in the air, and when hydrogen gas supplied to the hydrogen electrode of the fuel cell is hydrogen ionized by an electrochemical reaction. Electrons moving from the hydrogen electrode to the oxygen electrode can be taken out as a direct current by an external circuit. Since part of the hydrogen gas supplied to the hydrogen electrode is discharged from the fuel cell stack in an unreacted state, a circulation system is provided in which the unreacted off-gas is returned to the fuel cell stack again for effective use.

  The introduced off gas contains hydrogen gas and reaction water circulating in the fuel cell stack. The hydrogen gas and reaction water contain trace amounts of impurities that are dissolved from the fuel cell stack and piping components. Impurities may also enter from the air sucked from outside air and pass through the electrolyte membrane and enter the hydrogen gas circulation system. Therefore, an ion exchange filter is provided in the hydrogen gas circulation system, and an ion exchange filter that suppresses deterioration of the fuel cell stack due to reaction water, hydrogen gas, air, and the like is provided.

  Patent Document 1 discloses a gas-liquid separator that incorporates an ion exchange filter capable of reliably removing reaction water flying in particulate form and impurities mixed in the reaction water in an exhaust gas passage. It is shown.

  Patent Document 2 relates to an ion exchange filter that removes ions contained in reaction water generated or used in a fuel cell system outside the fuel cell stack, and enters the ion exchange filter in an environment of zero degrees or less. A technique for preventing reaction water from expanding due to freezing and damaging the ion exchange filter is disclosed.

JP 2005-285735 A JP 2006-286544 A

  In the above-mentioned patent documents, the ion exchange filter that can reliably remove impurities mixed in the reaction water in the exhaust gas passage, or the reaction water that has entered the ion exchange filter in an environment of zero degrees or less is frozen. It is intended to prevent the ion exchange filter from damaging due to expansion, but is not configured to encourage the active drainage of unnecessary residual water (reaction water) contained in the ion exchange filter. The amount of passage may be reduced.

  Then, an object of this invention is to provide the fuel cell system which accelerates | stimulates the waste_water | drain in an ion exchange filter and does not leave unnecessary residual water inside.

  In order to achieve the above object, a fuel cell system according to the present invention is mounted on a vehicle and has a gas-liquid separator in an exhaust gas passage through which off-gas from the fuel cell flows. The separator includes an upper chamber for separating liquid contained in the off-gas of the fuel cell, an ion exchanger provided in the upper chamber, and a lower chamber in which a drainage unit for collecting and draining the separated liquid is formed. , And a guide member that promotes the drop of the liquid droplets extends vertically downward on the bottom surface of the ion exchanger.

  In the fuel cell system according to the present invention, the guide member is a rod-shaped protrusion.

  In the fuel cell system according to the present invention, the guide member is a conical protrusion having a thick root portion and a thin tip portion.

  Furthermore, in the fuel cell system according to the present invention, the guide member has a horizontally long rectangular rib and a triangular rib, the rectangular rib is disposed along the flow of off-gas, and the triangular rib is a rectangular rib. It is characterized by being arranged orthogonally.

  When the gas-liquid separator of the fuel cell system according to the present invention is used, positive drainage of unnecessary residual water contained in the ion exchange filter can be promoted, and the effect of preventing a decrease in the amount of off-gas passage can be prevented. There is.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

  FIG. 1 shows the configuration of the fuel cell system 1. The fuel cell system 1 includes a fuel cell stack 10, a gas-liquid separator 20, a diluter 16, a hydrogen supply valve 11, a pump 13 and a pump motor 12, a drain valve controller 15, and a fuel cell control device 14. And. The hydrogen gas flows into the hydrogen supply flow passage 41 and is introduced into the fuel cell stack 10 by opening the hydrogen supply valve 11. In the fuel cell stack 10, oxygen in the air is introduced in addition to hydrogen gas, an electric current is generated by an electrochemical reaction, and reaction water is generated. From the fuel cell stack 10, off-gas containing unreacted hydrogen gas and reaction water flows through the off-gas flow passage 42 and is introduced into the gas-liquid separator 20.

  The gas-liquid separator 20 includes an ion exchange filter 30 provided with a guide member that promotes the drop of droplets on the bottom surface. Is released. The hydrogen gas from which the reaction water has been separated is returned again to the hydrogen supply flow passage 41 by the pump 13.

  FIG. 2 shows a front view and a top view of the gas-liquid separator 20 in the fuel cell system. As shown in the figure, the length (W) of the gas-liquid separator 20 in the drain direction is set longer than the depth direction (D), and the gas-liquid separator 20 and the piping are combined. The gas-liquid separator 20 also includes an off-gas introduction pipe 21 for introducing off-gas, an upper chamber 22 into which the introduced off-gas first enters, a lower chamber 23 in which reaction water is temporarily stored, and reaction water. It has a drain valve 25 for discharging, a discharge pipe 26 connected to the drain valve 25, and a circulation discharge pipe 24 from which hydrogen gas from which reaction water has been separated is discharged.

  FIG. 3 shows the appearance of the ion exchange filter 30 built in the gas-liquid separator 20. For explanation, the bottom surface of the ion exchange filter 30 is shown as a front view, and the side surface of the ion exchange filter 30 is shown as a top view. In the ion exchange filter 30, a space formed by the filter case 32 and the nets 33 and 35 is filled with an ion exchange resin 34. On the bottom surface of the ion exchange filter 30, there are provided a net 33 for holding the ion exchange resin 34, and a rib 31 for supporting the net 33 and a guide member 36 having a tip formed of a spherical rod. The reaction water contained in the granular resin 37 itself and the reaction water flowing through the gaps between the granular resins 37 are transmitted to the outside of the ion exchange filter 30 by the guide member 36 that travels through the net 33 and the rib 31 and promotes the drop of the droplets. To be drained.

  FIG. 4 shows a cross section of the gas-liquid separator 20 different from the ion exchange filter 30 of FIG. 3 is different from FIG. 3 in that the drop of the droplet is promoted and the reaction water returning into the ion exchange filter 30 by the off-gas flow reverse to the direction of the drop of the droplet is reduced. It is replaced by a conical protrusion. This is because droplets are easily transmitted to the root of the conical protrusion, and the droplet once transmitted to the root is difficult to reverse.

  The off gas introduced from the off gas introduction pipe 21 to the gas-liquid separator 20 includes hydrogen gas and reaction water circulating in the fuel cell stack 10. Trace amounts of impurities contained in the hydrogen gas and reaction water enter from the bottom surface of the ion exchange filter 30 and are adsorbed and removed by the internal ion exchange resin 34. Further, the hydrogen gas from which impurities have been removed is discharged from the upper surface of the ion exchange filter 30 to the circulation discharge pipe 24. Similarly, the reaction water from which impurities have been removed proceeds in the opposite direction to the off-gas flow due to gravity, and the ion exchange filter. It is transmitted to the conical protrusion 39 provided on the bottom surface of 30 and dropped from the tip. Although not shown in FIG. 4, a hollow portion may be provided at the center of the conical protrusion 39 to form a pipe.

  The off gas introduced into the upper chamber 22 from the off gas introduction pipe 21 in FIG. 4 is separated into hydrogen gas and reaction water, and is discharged from the circulation discharge pipe 24. In addition, the reaction water passes along the side surface and the inclined bottom surface of the upper chamber 22, passes through the communication hole 27, and is temporarily stored in the lower chamber 23 (reaction water 32). The drainage of the stored reaction water 32 is controlled by the fuel cell control device and the drain valve controller, and the reaction water 32 is discharged by a synergistic effect of the pressure of the hydrogen gas and the flow rate of the hydrogen gas flowing through the communication hole 27. Perform flush drainage that blows off instantaneously.

  FIG. 5 shows the appearance of the gas-liquid separator 20 having the ion exchange filter 30 that promotes the drop dropping using the off-gas flow. Note that the description of the same part is omitted.

  The off-gas introduction pipe 21 and the circulation discharge pipe 24 of the gas-liquid separator 20 of FIG. 5 are desirably separated to improve ion exchange efficiency, but the circulation discharge pipe 24 is off-gas in order to shorten the off-gas flow path. It is approaching the introduction pipe 21. Therefore, in the present embodiment, a wind guide triangular rib 38 that guides off gas is provided as a guide member, and the off gas flow is efficiently guided to the back of the ion exchange filter 30.

  The air guide triangular rib 38 has a horizontally long rectangular rib and a triangular rib. The rectangular rib is arranged along the flow of off-gas, and the triangular rib is arranged orthogonal to the rectangular rib. In addition, the rectangular rib is set such that the height of the guide portion is low in the vicinity of the off-gas inlet, and the height of the guide portion is set higher toward the back. For this reason, the off gas near the off gas introduction port is guided to the back side while maintaining the ejection speed, and is guided to the bottom corners of the ion exchange filter 30.

  As described above, by using the gas-liquid separator according to the present embodiment, aggressive drainage of unnecessary residual water contained in the ion exchange filter can be promoted, and a decrease in the amount of off-gas passage is prevented. It becomes possible. In addition, since the height of the protrusion provided as a guide member, thickness, and the number differ in every fuel cell system, it cannot be overemphasized that it is necessary to set the optimal value for every fuel cell system.

It is a block diagram which shows the structure of the fuel cell system which concerns on embodiment of this invention. It is explanatory drawing explaining the external appearance of the gas-liquid separator provided in the fuel cell system of this embodiment. It is explanatory drawing explaining the external appearance of the ion exchange filter incorporated in the gas-liquid separator of this embodiment. It is explanatory drawing explaining the ion exchange filter of another form incorporated in the gas-liquid separator of this embodiment. It is explanatory drawing explaining the ion exchange filter of another form incorporated in the gas-liquid separator of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel cell system, 10 Fuel cell stack, 11 Hydrogen supply valve, 12 Pump motor, 13 Pump, 14 Fuel cell control apparatus, 15 Drain valve controller, 16 Diluter, 20 Gas-liquid separator, 21 Off-gas introduction pipe, 22 Upper chamber, 23 Lower chamber, 24 Circulation discharge pipe, 25 Drain valve, 26 Drain pipe, 27 Communication hole, 30 Ion exchange filter, 31 Rib, 32 Filter case, 32 Reaction water, 33, 35 Net, 34 Ion exchange resin , 36 guide member, 37 granular resin, 38 air guide triangular rib, 39 conical protrusion, 41 hydrogen supply flow passage, 42 off-gas flow passage, 44 drainage flow passage.

Claims (4)

In a fuel cell system that is mounted on a vehicle and has a gas-liquid separator in an exhaust gas passage through which off-gas from the fuel cell flows,
The gas-liquid separator
An upper chamber for separating liquid contained in the off-gas of the fuel cell;
An ion exchanger provided in the upper chamber;
A lower chamber in which a drainage part for collecting and draining the separated liquid is formed;
Have
A fuel cell system, characterized in that a guide member that prompts the drop of a droplet extends vertically downward on the bottom surface of the ion exchanger. The fuel cell system according to claim 1,
The fuel cell system, wherein the guide member is a rod-shaped protrusion. The fuel cell system according to claim 1,
The fuel cell system, wherein the guide member is a conical protrusion having a thick root portion and a thin tip portion. The fuel cell system according to claim 1,
The guide member has a horizontally long rectangular rib and a triangular rib, the rectangular rib is disposed along the flow of off-gas, and the triangular rib is disposed orthogonal to the rectangular rib. Fuel cell system.

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