JP5330736B2 - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of suitably exhausting moisture. <P>SOLUTION: The fuel cell system includes an anode offgas exhausting path exhausting anode offgas from a fuel cell, a cathode offgas exhaust path exhausting cathode offgas from the fuel cell, a gas-liquid separator 13 installed in the anode offgas exhaust path and separating moisture contained in the anode offgas, and a drain exhaust path including a drain valve 30 which controls exhaust moisture separated at the gas-liquid separator 13. At least either the anode offgas exhaust path or the cathode offgas exhaust path is joined to the drain exhaust path, and the exhausted moisture from the drain valve 30 is discharged with assistance of flows of the anode offgas or the cathode offgas. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a fuel cell system.

In recent years, a polymer electrolyte fuel cell (Polymer Electrolyte Fuel Cell) that generates electricity by supplying hydrogen (fuel gas, reactive gas) to the anode and oxygen-containing air (oxidant gas, reactive gas) to the cathode, respectively. The development of fuel cells such as PEFC is active.
In such a system using a fuel cell, hydrogen (fuel gas) supplied to the anode electrode is hydrogen ionized in the catalyst layer and emits electrons. These electrons are taken out when flowing through an external circuit toward the cathode and are used as direct current electric energy. The hydrogen ions move to the cathode electrode through the solid polymer electrolyte membrane, and water is generated by combining oxygen (oxidant gas) supplied to the cathode electrode and electrons that have reached through the external circuit. The

  By the way, since the solid polymer electrolyte membrane needs an appropriate humidity to maintain its ion permeability, hydrogen and oxygen are supplied to the fuel cell in an appropriately humidified state. For this reason, the anode off-gas discharged from the anode of the fuel cell and the cathode off-gas discharged from the cathode contain a large amount of moisture that was not absorbed by the solid polymer electrolyte membrane and moisture as a reaction product.

  Therefore, conventionally, a gas-liquid separation device is provided in the anode off-gas discharge passage, and water is separated from the anode off-gas by the gas-liquid separation device, and the separated water is discharged through the drain discharge passage. Has been proposed (see Patent Documents 1 and 2). Here, a drain valve is installed in the drain discharge path.

  On the other hand, when water accumulates on the anode side, the supply of fuel gas is hindered, and power generation may become unstable. In addition, since nitrogen in the air supplied to the cathode passes through the electrolyte membrane to the anode side even though a small amount is mixed into the fuel gas, power generation may become unstable if the concentration of nitrogen increases due to recycling of the fuel gas. is there.

  Therefore, conventionally, a purge valve is provided in the fuel gas circulation passage, and water accumulated in the anode and nitrogen mixed in the fuel gas are discharged to recover the power generation state.

JP 2006-156093 A JP 2007-18910 A

In the fuel cell system of Patent Document 1, it has been desired to improve the moisture discharging property in order to further smoothly drain the water discharged from the drain discharge path.
By the way, it is not preferable to improve the discharge performance by opening the drain valve because the anode off gas is discharged more than necessary from the drain valve.

  Moreover, in the said patent document 2, what the drain discharge path merges with respect to the anode off-gas discharge path is described. However, the relationship between the water flowing through the drain discharge path and the anode off gas flowing through the anode off gas discharge path has not been clearly described.

  Then, this invention makes it a subject to provide the fuel cell system which can drain | emit water suitably.

In order to achieve the above object, a fuel cell system according to the present invention is a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas to generate power, and discharges anode off-gas from the fuel cell. Drain discharge including an off-gas discharge path, a gas-liquid separation device that is provided in the anode off-gas discharge path and separates water accompanying the anode off-gas, and a drain valve that controls discharge of water separated by the gas-liquid separation device A purge valve that discharges the remaining anode offgas from which moisture has been separated by the gas-liquid separator to the anode offgas discharge path, and joins the anode offgas discharge path and the drain discharge path, Utilizing the flow of the anode off gas discharged to the anode off gas discharge path by the purge valve, Serial is characterized in that so as to assist the discharge of water coming be discharged from the drain valve.

  According to this fuel cell system, the discharge of moisture discharged from the drain valve is assisted by using the flow of the anode off gas discharged to the anode off gas discharge passage by the purge valve, so that the water is smoothly discharged. It is possible to improve the moisture discharge performance.

  A circulation path for returning the remaining anode offgas from which water has been separated by the gas-liquid separator to the anode gas supply side of the fuel cell; and the purge valve is provided in the circulation path; It is good to do.

  According to this fuel cell system, the anode off gas is returned to the anode gas supply side of the fuel cell by the circulation path, and unused hydrogen can be effectively used. Further, since the remaining anode off gas that has not been used for purging is returned to the anode gas supply side of the fuel cell through the circulation path, it can be suitably prevented from staying in the flow path.

The purge valve may be configured to open after the drain valve is opened.
According to this fuel cell system, since the drain valve opens and the purge valve opens after moisture flows through the drain discharge path, for example, the merging position of the anode off-gas discharge path and the drain discharge path is determined. By setting the opening timing of the purge valve so that the anode off gas is supplied at the timing when moisture passes, moisture can be suitably discharged using the anode off gas flow effectively.

  Moreover, it is preferable that the downstream side of the combined flow path of the anode offgas discharge path and the drain discharge path is connected to a diluter that dilutes the anode offgas.

  According to this fuel cell system, hydrogen accompanying water can be diluted with a diluter, and water can be appropriately discharged out of the system through the diluter.

  The anode off-gas discharge path and the drain discharge path are merged on the downstream side of the drain valve, and an orifice is provided in the drain discharge path on the upstream side from the merge position. Good.

  According to this fuel cell system, by providing the orifice, the amount of drainage is regulated to a constant amount, and the purge valve is opened so as to purge it. By providing such an orifice, it is possible to suitably avoid the possibility that not only the moisture but also the anode off-gas will be discharged together, and the moisture that has been squeezed by the orifice to become a small amount is preferably purged. Can be discharged. In particular, in an operating situation where the fuel cell has a small load and a small amount of anode off gas, it is possible to suitably avoid the anode off gas being discharged together with moisture.

  Moreover, it is preferable that the drain discharge path is joined to the anode off gas discharge path from above the anode off gas discharge path.

According to this fuel cell system, since the drain discharge path is joined to the anode off gas discharge path from the upper side of the anode off gas discharge path, the water flowing through the drain discharge path is caused by gravity to the anode off gas discharge path. It will flow down and will be suitably discharged by the anode offgas flowing through the anode offgas discharge path. Therefore, the discharge of moisture flowing through the drain discharge path is favorably assisted by the flow of the anode off gas, and the discharge performance is improved.
Further, since the drainage can be controlled by opening and closing the purge valve, the valve opening time of the drain valve can be set considering only the amount of drainage of moisture. Therefore, the valve opening time of the drain valve can be shortened, and in the case of a normally closed drain valve, power consumption can be suppressed accordingly.

  In addition, a configuration is provided in which a venturi portion that sucks out moisture in the drain discharge passage to the anode off gas discharge passage side using negative pressure is provided at a joining position of the anode off gas discharge passage with the drain discharge passage. It is good to do.

  According to this fuel cell system, the water in the drain discharge path is sucked out to the anode off-gas discharge path side by using the negative pressure by the venturi section, and the discharge performance is improved. In other words, it is possible to discharge water well without increasing the purge amount. Further, since the discharge performance can be improved by using the flow velocity, the drain valve opening time can be shortened as a result, and the power consumption can be suppressed accordingly.

  Further, the anode off-gas discharge path and the drain discharge path are preferably joined on the upstream side of the drain valve.

According to this fuel cell system, since the anode off-gas discharge path and the drain discharge path are merged on the upstream side of the drain valve, the discharge is controlled by the drain valve after the anode off-gas and moisture are merged. Thus, moisture can be discharged with the assist of the anode off-gas.
Further, since the moisture discharge control can be performed only by the drain valve opening / closing control, the control is simple, the management of the hydrogen discharge concentration is simplified, and the dilution by the diluter can be suitably performed.

  The fuel cell system of the present invention is a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas to generate power, the anode off-gas discharge path for discharging the anode off-gas from the fuel cell, A gas-liquid separation device that is provided in the anode off-gas discharge passage and separates the water accompanying the anode off-gas, a drain discharge passage that discharges water separated by the gas-liquid separation device, and a drain discharge passage provided in the drain discharge passage. An orifice, and a purge valve that discharges the remaining anode off-gas from which water has been separated by the gas-liquid separator to the anode off-gas discharge path, the anode off-gas discharge path and the drain discharge path being the orifice The anode is discharged to the anode off-gas discharge passage by the purge valve. Utilizing the flow of Doofugasu, characterized in that so as to assist the discharge of water to be discharged through said orifice.

  According to this fuel cell system, since the drain valve is eliminated from the drain discharge path by providing the orifice in the drain discharge path, the configuration is simplified and the cost can be reduced. Further, since the drain valve is eliminated, drainage control is simplified correspondingly, and power consumption can be suppressed.

The fuel cell system of the present invention is a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas to generate power, the anode off-gas discharge path for discharging the anode off-gas from the fuel cell, A cathode offgas discharge passage for discharging the cathode offgas from the fuel cell; a gas-liquid separation device provided in the anode offgas discharge passage for separating moisture accompanying the anode offgas; and water separated by the gas-liquid separation device. a drain discharge path including a drain valve for controlling the discharge, wherein a back pressure valve for controlling the pressure of the cathode off-gas from the fuel cell, is combined with said drainage path and the cathode off-gas discharge path, the downstream side of the combined channel And connected to the downstream side of the anode offgas discharge path, the anode offgas And a diluter for diluting the anode off gas discharged through the Detchi, by utilizing the flow of the cathode off-gas discharged to the cathode off-gas discharge passage by the back pressure valve, come discharged from the drain valve It is characterized by assisting the discharge of moisture toward the diluter .

According to this fuel cell system, the flow of the cathode off gas used in the fuel cell is used to assist the discharge of the water discharged from the drain valve, so that the water is discharged smoothly and the moisture is discharged. Emission can be improved.
Further, hydrogen accompanying water can be diluted with a diluter, and the water can be appropriately discharged out of the system through the diluter.

The back pressure valve may be configured to open after the drain valve is opened.
According to this fuel cell system, since the drain valve opens and the back pressure valve opens after moisture flows through the drain discharge passage, for example, the merging position of the cathode offgas discharge passage and the drain discharge passage is determined. By setting the valve opening timing of the back pressure valve so that the cathode off gas is supplied at the timing when moisture passes, it is possible to suitably discharge moisture using the cathode off gas flow effectively.

  The cathode offgas discharge path and the drain discharge path are merged on the downstream side of the drain valve, and an orifice is provided in the drain discharge path on the upstream side from the merge position. Good.

  According to this fuel cell system, by providing the orifice, the amount of drainage is regulated to a certain amount, and the back pressure valve is opened so as to purge it, and the orifice is throttled and discharged in a small amount. Moisture can be suitably discharged by the cathode off gas.

  The drain discharge path may be configured to merge with the cathode offgas discharge path from above the cathode offgas discharge path.

According to this fuel cell system, since the drain discharge path is joined to the cathode off gas discharge path from the upper side of the cathode off gas discharge path, the water flowing through the drain discharge path is caused by gravity to the cathode off gas discharge path. It flows down and is suitably discharged by the cathode offgas flowing through the cathode offgas discharge passage. Therefore, the discharge of moisture flowing through the drain discharge path is favorably assisted by the flow of the cathode off gas, and the discharge performance is improved.
Further, since the drainage can be controlled by opening and closing the back pressure valve, the opening time of the drain valve can be set considering only the amount of water drainage. Therefore, the valve opening time of the drain valve can be shortened, and power consumption can be suppressed accordingly.

  In the cathode offgas discharge path, a venturi section is provided at a position where the cathode offgas discharge path joins the drain discharge path, and draws moisture in the drain discharge path to the anode offgas discharge path side using negative pressure. Is good.

  According to this fuel cell system, moisture in the drain discharge path is sucked out to the cathode off-gas discharge path side by using the negative pressure by the venturi section, and the discharge performance is improved. That is, good drainage is possible without increasing the purge amount. Further, since the discharge performance can be improved by using the flow velocity, the drain valve opening time can be shortened as a result, and the power consumption can be suppressed accordingly.

  The cathode offgas discharge passage and the drain discharge passage may be joined on the upstream side of the drain valve.

According to this fuel cell system, since the cathode offgas discharge passage and the drain discharge passage are merged on the upstream side of the drain valve, the discharge is controlled by the drain valve after the cathode offgas and moisture are merged. Thus, moisture can be discharged with the assistance of the cathode off-gas.
In addition, since the moisture discharge control can be performed only by the open / close control of the drain valve, the control is simple, the management of the hydrogen discharge concentration is simplified, and the dilution by the diluter can be suitably performed.

  The fuel cell system of the present invention is a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas to generate power, the anode off-gas discharge path for discharging the anode off-gas from the fuel cell, A cathode offgas discharge passage for discharging the cathode offgas from the fuel cell; a gas-liquid separation device provided in the anode offgas discharge passage for separating moisture accompanying the anode offgas; and water separated by the gas-liquid separation device. A drain discharge path for discharging, an orifice provided in the drain discharge path, and a back pressure valve for controlling the pressure of the cathode off gas from the fuel cell, the cathode off gas discharge path and the drain discharge path Merged downstream of the orifice and discharged into the cathode offgas discharge passage by the back pressure valve. Wherein by utilizing the flow of the cathode off-gas, is characterized in that so as to assist the discharge of water to be discharged through said orifice.

  According to this fuel cell system, since the drain valve is eliminated from the drain discharge path by providing the orifice in the drain discharge path, the configuration is simplified and the cost can be reduced. Moreover, since the drain valve is eliminated, drainage control is simplified correspondingly, and power consumption can be suppressed.

  According to the present invention, a fuel cell system capable of suitably draining water can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. In the description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.
(First embodiment)
≪Configuration of fuel cell system≫
In FIG. 1, a fuel cell system 1 according to the present embodiment is mounted on a fuel cell vehicle (moving body) (not shown). The fuel cell system 1 includes a fuel cell stack 2, an anode system 4 that supplies and discharges hydrogen (fuel gas and reaction gas) to and from the anode of the fuel cell stack 2, and oxygen to the cathode of the fuel cell stack 2. And a cathode system 6 for supplying and discharging air (oxidant gas, reaction gas).

<Fuel cell stack>
The fuel cell stack 2 is a stack formed by stacking a plurality of (for example, 200 to 400) solid polymer type single cells, and the plurality of single cells are electrically connected in series. The single cell includes an MEA (Membrane Electrode Assembly) and two conductive anode separators and cathode separators sandwiching the MEA.

  The MEA includes an electrolyte membrane (solid polymer membrane) made of a monovalent cation exchange membrane (for example, perfluorosulfonic acid type), and an anode and a cathode sandwiching the electrolyte membrane. The anode and the cathode are mainly composed of a conductive porous material such as carbon paper, and contain a catalyst (Pt, Ru, etc.) for causing an electrode reaction in the anode and the cathode.

The anode separator is formed with a through-hole (called an internal manifold) extending in the stacking direction of the single cells and a groove extending in the surface direction of the single cells in order to supply and discharge hydrogen to the anode of each MEA. These through holes and grooves function as the anode flow path 2A (fuel gas flow path).
The cathode separator is formed with a through-hole (referred to as an internal manifold) extending in the stacking direction of the single cells and a groove extending in the surface direction of the single cells in order to supply and discharge air to and from the cathode of each MEA. These through holes and grooves function as the cathode channel 2B (oxidant gas channel).

When hydrogen is supplied to each anode via the anode flow path 2A, an electrode reaction of the following formula (1) occurs, and when air is supplied to each cathode via the cathode flow path 2B, An electrode reaction of the following formula (2) occurs, and a potential difference (OCV (Open Circuit Voltage), open circuit voltage) is generated in each single cell. When the fuel cell stack 2 and an external circuit such as a travel motor are electrically connected and current is taken out, the fuel cell stack 2 generates power.
2H ₂ → 4H ⁺ + 4e ⁻ (1)
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)

  When the fuel cell stack 2 generates power in this way, a part of the water (water vapor) generated at the cathode permeates the electrolyte membrane and moves to the anode. Therefore, both the cathode offgas discharged from the cathode and the anode offgas discharged from the anode are humid.

<Anode system>
The anode system is provided upstream of the fuel cell stack 2, and is provided downstream of the hydrogen tank 10 (fuel gas supply means), the normally closed shut-off valve 11, the ejector 12, and the fuel cell stack 2. A gas-liquid separator (gas-liquid separator) 13 and a normally closed purge valve 14 are provided.

The hydrogen tank 10 is connected to the inlet side of the anode flow path 2A via a pipe 11a, a shutoff valve 11, a pipe 12a, an ejector 12, and a pipe 12b. The piping 11a is provided with a pressure reducing valve (not shown) for reducing hydrogen to a predetermined pressure. The pressure of the air toward the cathode flow path 2B is input to the pressure reducing valve as a signal pressure (pilot pressure). The pressure reducing valve corresponds to the pressure of the air and the pressure of hydrogen in the anode flow path 2A. Control is performed so as to fluctuate.
Then, when the ignition of the fuel cell vehicle is turned on, the start of the fuel cell stack 2 is requested, and the shutoff valve 11 is opened by the ECU (Electronic Control Unit) 20, the hydrogen in the hydrogen tank 10 passes through the pipe 11a and the like. It is supplied to the anode flow path 2A.

The outlet of the anode channel 2A is connected to the suction port of the ejector 12 through the pipe 13a, the gas-liquid separator 13, the pipe 13b, and the pipe 13c. The anode off gas containing unreacted hydrogen discharged from the anode channel 2A (anode) is separated from the liquid water accompanying the anode off gas in the gas-liquid separator 13 and then upstream of the fuel cell stack 2. This is returned to the ejector 12.
The anode off gas returned to the ejector 12 is mixed with hydrogen from the hydrogen tank 10 and then supplied again to the anode flow path 2A. That is, in this embodiment, the piping 13a, 13b and the piping 13c constitute a hydrogen circulation path for circulating and reusing hydrogen.
In addition, the part close to the gas-liquid separator 13 side of the pipe 13b is arranged in the vertical direction, and when moisture accompanying the anode off-gas is contained, it is returned to the gas-liquid separator 13 by its own weight. It has become.

  On the other hand, the water separated by the gas-liquid separator 13 is temporarily stored in the gas-liquid separator 13 and then opened normally by the pipe 30a and the ECU 20, and the normally closed drain valve 30, the pipe 30b, the pipe 31 is discharged to a diluter 43 which will be described later. In this example, the pipe 30a and the pipe 30b correspond to the drain discharge path referred to in the claims, and the drain valve 30 is provided in the drain discharge path. Moreover, the piping 31 is corresponded to the joint channel said to a claim.

[Purge valve]
The purge valve 14 is a normally-closed solenoid valve that discharges impurities (water vapor, nitrogen, etc.) contained in the anode off-gas (hydrogen) circulating through the pipe 13a and the pipe 13b during power generation of the fuel cell stack 2 (purge). The valve is opened by the ECU 20 when the water stored in the gas-liquid separator 13 is discharged through the drain valve 30 as will be described later. The upstream side of the purge valve 14 is connected to the pipe 13b via the pipe 14a, and the downstream side is connected to the pipe 30b via the pipe 14b and joins the drain discharge path (pipe 30b). In this example, the pipe 13a and the pipe 13b on the upstream side of the circulation path and the pipe 14a and the pipe 14b branched from the circulation path correspond to the anode off-gas discharge path referred to in the claims. A gas-liquid separator 13 and a purge valve 14 are provided in the path.

  The drain discharge path and the anode off-gas discharge path are merged on the downstream side of the drain valve 30. In this embodiment, as shown in FIG. 1B, the anode off-gas discharge path is connected to the pipe 30b forming the drain discharge path. The piping 14b which comprises is joining in the downward inclination shape toward the downstream direction (direction which follows the flow of a water | moisture content) from the upper side. As a result, the anode off gas from the anode off gas discharge passage smoothly flows into the pipe 31, and the drainage of moisture is suitably assisted by the flowing anode off gas. That is, as will be described later, the moisture discharged through the pipe 30b forming the drain discharge path smoothly flows into the pipe 31 from the joining position, and flows in the pipe 31 toward the downstream side. The moisture that has been discharged is suitably discharged to the diluter 43 on the downstream side by being pushed by the anode off-gas that has flowed.

  Here, the pipe 14b that forms the anode off-gas discharge path is larger in diameter than the pipe 30b that forms the drain discharge path, and the pipe 31 that is on the downstream side of the joining position has substantially the same diameter as the pipe 14b. That is, the pipe 31 has a large diameter along the pipe 14b on the downstream side of the joining position. This realizes a smooth flow of moisture and anode off-gas.

  Here, the ECU 20 calculates and monitors the volume of water stored in the gas-liquid separator 13 from the operating status of the fuel cell stack 2, and the moisture is, for example, a predetermined maximum volume set in advance. At that time, the drain valve 30 is controlled to open, and the purge valve 14 is controlled to open. In other words, the flow of the anode off-gas discharged from the purge valve 14 is used to control the discharge of moisture discharged from the drain valve 30.

In this embodiment, ON (open) / OFF (closed) control of the drain valve 30 and ON (open) / OFF (closed) control of the purge valve 14 are stored in the gas-liquid separator 13. Corresponding to the volume of moisture to be controlled, it is related and controlled as follows.
That is, as shown in FIG. 2, when the water volume obtained by the calculation of the ECU 20 reaches a predetermined maximum volume, the ECU 20 (see FIG. 1) first opens the drain valve 30. The valve opening control is performed first, and the purge valve 14 is controlled to open after a predetermined time has elapsed. That is, the ECU 20 performs control so that the purge valve 14 is opened after the drain valve 30 is opened first, and the valve opening control is performed with a delay time between the drain valve 30 and the purge valve 14. .

  Thus, when the drain valve 30 is opened first, the moisture is discharged to the pipe 30b through the drain valve 30, and the discharged moisture is joined before the anode off-gas from the purge valve 14. It reaches the position (or flows into the pipe 31 from the merging position). Then, when the purge valve 14 is opened at a timing at which such moisture reaches the merging position (a timing based on a preset delay time), the flow of the anode off-gas discharged through the purge valve 14 causes the merging position. Or the water | moisture content which flowed into the piping 31 from the confluence | merging position can be pushed downstream (diluter 43 side). Accordingly, the discharge of moisture discharged from the drain valve 30 is assisted using the flow of the anode off gas, and the moisture stored in the gas-liquid separator 13 is reduced to the minimum volume. Thereafter, the drain valve 30 and the purge valve 14 are closed, and the interlocking operation between the drain valve 30 and the purge valve 14 ends.

In addition to the function of assisting the drainage of moisture, the purge valve 14 is configured so that when the voltage of the single cell (cell voltage) constituting the fuel cell stack 2 becomes equal to or lower than a predetermined cell voltage, the ECU 20 It is determined that it is necessary to discharge and the ECU 20 opens the valve. The cell voltage is detected, for example, via a voltage sensor (cell voltage monitor) that detects the voltage of a single cell, and is input to the ECU 20. The purge valve 14 is opened in accordance with a command from the ECU 20, and the anode off gas sent from the anode flow path 2 </ b> A of the fuel cell stack 2 is discharged to the subsequent-stage diluter 43 through the pipe 14 b and the pipe 31. In addition, even if the anode off gas flowing at this time has moisture remaining in the pipe 31, it is suitably discharged.
Further, the opening operation of the purge valve 14 and the drain valve 30 is not limited to the interlocking operation, and may be performed independently. In this case, it is possible to assist the discharge of moisture while adjusting the hydrogen state by purging.

  In addition, an orifice (not shown) is provided in the drain discharge path upstream from the joining position of the anode off-gas discharge path and the drain discharge path. By providing such an orifice, the amount of drainage is regulated to a constant amount, and the purge valve 14 is opened so as to purge it. By providing such an orifice, it is possible to suitably avoid the possibility that not only the moisture but also the anode off-gas is discharged together, and the purged water that is squeezed by the orifice and is discharged in a small amount is suitable. Can be discharged. In particular, in an operating situation where the fuel cell has a small load and a small amount of anode off gas, it is possible to suitably avoid the anode off gas being discharged together with moisture.

<Cathode system>
Returning to FIG. 1, the description will be continued.
The cathode system 6 includes a compressor 40 (oxidant gas supply means), a humidifier 41, a back pressure valve 42, and a diluter 43 (gas treatment device).

The compressor 40 is connected to the inlet of the cathode flow path 2B via a pipe 41a, a humidifier 41, and a pipe 41b. And if it act | operates according to the instruction | command of ECU20, the compressor 40 will take in the air containing oxygen, and will supply air to the cathode flow path 2B. Further, the compressor 40 functions as a scavenging means for scavenging the fuel cell stack 2 during scavenging.
The compressor 40 operates using a fuel cell stack 2 and / or a high-voltage battery (not shown) that charges and discharges the power generated by the fuel cell stack 2 as a power source.

The outlet of the cathode channel 2B is connected to the diluter 43 via a pipe 42a, a back pressure valve 42, and a pipe 42b. The humid cathode off gas discharged from the cathode channel 2B is supplied to the diluter 43 via the pipe 42a and the like.
The back pressure valve 42 is a valve that controls the pressure of air in the cathode flow path 2B, and includes a butterfly valve or the like.

<Humidifier>
The humidifier 41 includes a hollow fiber membrane (not shown) that exchanges moisture between the air that travels from the compressor 40 toward the cathode flow path 2B and the air that travels toward the cathode flow path 2B and the humid cathode offgas.

<Diluter>
The diluter 43 is a container that mixes the anode off-gas introduced from the purge valve 14 and the cathode off-gas (dilution gas) introduced from the pipe 42b, and dilutes hydrogen in the anode off-gas with the cathode off-gas, It has a dilution space inside. The gas diluted by the diluter 43 is discharged outside the vehicle.

  According to the fuel cell system of the present embodiment described above, the flow of the anode off gas used in the fuel cell stack 2 is used to assist the discharge of the water discharged from the drain valve 30. The discharging is performed smoothly, and the moisture discharging property can be improved.

  In addition, since the anode offgas discharged to the anode offgas discharge path by the purge valve 14 assists the discharge of moisture discharged from the drain valve 30, the anode offgas discharged by the purge is effectively used. In other words, moisture can be discharged.

  Further, since the circulation path is provided, the anode off gas is returned to the anode gas supply side of the fuel cell stack 2 by this circulation path, and unused hydrogen can be effectively used. Further, the remaining anode off gas that has not been used for purging is also returned to the anode gas supply side of the fuel cell stack 2 through the circulation path, so that it can be suitably prevented from staying in the flow path. .

  Further, during the interlocking operation, the purge valve 14 is opened after the drain valve 30 is opened. Therefore, after the drain valve 30 is opened and moisture flows through the drain discharge passage, the purge valve 14 is opened. For example, by setting the valve opening timing of the purge valve 14 so that the anode off gas is supplied at the timing when moisture passes through the joining position of the anode off gas discharge path and the drain discharge path, It is possible to suitably discharge moisture by effectively using the off-gas flow.

  Moreover, since the downstream side of the pipe 31 serving as a combined flow path of the anode off-gas discharge path and the drain discharge path is connected to the diluter 43, the hydrogen accompanying the moisture can be diluted by the diluter 43. Water can be appropriately discharged out of the system through the diluter 43.

(Second Embodiment)
FIG. 3A is a configuration diagram showing a fuel cell system according to a second embodiment of the present invention, and FIG. 3B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 3A and 3B, the pipe 30b that forms the drain discharge path on the downstream side of the drain valve 30 is connected to the pipe 14b from the upper side of the pipe 14b that forms the anode off-gas discharge path. It is different in the point of joining.
As shown in FIG. 3B, the drain valve 30 is located above the pipe 14b, and the drain discharge path joins the pipe 14b through the communication hole 33 provided at the lower end of the drain valve 30. It has become. In this example, since the drain discharge path is joined to the pipe 14b through the communication hole 33, the pipe 30b forming the drain discharge path is omitted.
The drain valve 30 includes a solenoid (not shown), a valve body 32 driven by the solenoid and the like, and a communication hole 33, and a valve seat (not shown) provided on the upper side of the communication hole 33. The drain valve 30 is closed by being seated on the valve body, and the valve body 32 is separated and opened by being driven upward by a solenoid or the like.

According to the fuel cell system 1, since the drain discharge path is joined to the anode off gas discharge path from the upper side of the anode off gas discharge path, the moisture flowing through the drain discharge path is caused by gravity due to gravity. It will flow down to (pipe 14b) and will be suitably discharged by the anode off gas flowing through the anode off gas discharge path. Therefore, the discharge of moisture flowing through the drain discharge path is favorably assisted by the flow of the anode off gas, and the discharge performance is improved.
Further, since the drainage can be controlled by opening and closing the purge valve 14, the opening time of the drain valve 30 can be set considering only the amount of drainage of moisture. Therefore, the valve opening time of the drain valve 30 can be shortened, and the power consumption can be suppressed accordingly.

(Third embodiment)
FIG. 4A is a configuration diagram showing a fuel cell system according to a third embodiment of the present invention, and FIG. 4B is a schematic enlarged view showing a merging position.
In the present embodiment, as shown in FIGS. 4A and 4B, the upstream side of the drain valve 30 is that the pipe 14b forming the anode off-gas discharge path and the pipe 30a forming the drain discharge path are merged. Is different.
As shown in FIG. 4B, the anode off-gas discharged from the purge valve 14 to the anode off-gas discharge path is introduced upstream of the valve body 32 of the drain valve 30, and the drain valve 30 By opening the valve in conjunction with the purge valve 14 as described above, moisture can be discharged with the assistance of the anode off gas.

According to this fuel cell system 1, the anode offgas discharge path and the drain discharge path are merged on the upstream side of the drain valve 30. Therefore, after the anode offgas and moisture are merged, the drain valve 30 discharges. By controlling, moisture can be suitably discharged.
Further, since the moisture discharge control can be performed only by the open / close control of the drain valve 30, the control is simple, the management of the hydrogen discharge concentration is simplified, and the dilution by the diluter 43 is also suitably performed. be able to.

(Fourth embodiment)
FIG. 5A is a configuration diagram showing a fuel cell system according to a fourth embodiment of the present invention, and FIG. 5B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 5 (a) and 5 (b), an orifice 50 is provided in the drain discharge passage, and the drain valve 30 (see FIG. 1, etc., the same applies hereinafter) is eliminated from the drain discharge passage. It is.
In this example, as shown in FIG. 5B, the pipe 14b forming the anode off-gas discharge path is inclined downward from the upper side to the downstream (direction along the flow of moisture) as shown in FIG. Have joined. As a result, the anode off-gas from the anode off-gas discharge passage smoothly flows into the pipe 31, and the drain off-path side is negatively assisted by this flowing-in anode off-gas so that moisture drainage is favorably assisted. Yes.

  According to the fuel cell system 1, since the drain valve 30 is eliminated, the configuration is simplified and the cost can be reduced. Further, since the drain valve 30 is eliminated, drainage control is simplified correspondingly, and power consumption can be suppressed.

ON (opening) / OFF (closing) control of the purge valve 14 is controlled in association with the volume of water stored in the gas-liquid separator 13 as follows.
That is, as shown in FIG. 6, when the volume of water determined by the calculation of the ECU 20 (see FIG. 5A, the same applies hereinafter) or the like becomes a predetermined volume set in advance, the ECU 20 The valve 14 is controlled to open. In other words, when the volume of moisture stored in the gas-liquid separator 13 reaches a predetermined volume, the moisture that has been discharged through the orifice 50 by a specified amount until then is obtained using the anode off gas from the purge valve 14. It can be discharged at once in a short time.

  Further, by providing the orifice 50, it is possible to suitably avoid the possibility that not only the moisture but also the anode off-gas is discharged together, and the water that has been squeezed by the orifice 50 and discharged in a small amount is purged. It can discharge suitably. In particular, in an operating situation where the fuel cell stack 2 is lightly loaded and has a small amount of anode offgas, it is possible to suitably drain moisture while avoiding the anode offgas being discharged together with moisture.

(Fifth embodiment)
FIG. 7A is a configuration diagram showing a fuel cell system according to a fifth embodiment of the present invention, and FIG. 7B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 7A and 7B, the pipe 42b forming the cathode off-gas discharge path merges with the pipe 30b forming the drain discharge path, and the cathode off-gas used in the fuel cell stack 2 The difference is that the flow is used to assist the discharge of moisture discharged from the drain valve 30.

In this example, as shown in FIG. 7B, the pipe 42b forming the cathode off-gas discharge path is inclined downward from the upper side to the downstream (direction along the flow of moisture). Have joined. As a result, the cathode offgas from the cathode offgas discharge passage smoothly flows into the pipe 31, and the drainage of moisture is suitably assisted by the flowing cathode offgas.
The back pressure valve 42 is opened after the drain valve 30 is opened.

According to the fuel cell system 1, the flow of the cathode off gas used in the fuel cell stack 2 is used to assist the discharge of the water discharged from the drain valve 30, so that the water can be discharged smoothly. It is possible to improve the drainage of moisture.
In addition, since the back pressure valve 42 is opened after the drain valve 30 is opened and moisture flows into the pipe 30b forming the drain discharge path, for example, moisture passes through the joining position of the pipe 42b and the pipe 30b. By setting the valve opening timing of the back pressure valve 42 so that the cathode off gas is supplied at the timing, it is possible to suitably discharge the moisture using the cathode off gas flow effectively.

(Sixth embodiment)
FIG. 8A is a configuration diagram showing a fuel cell system according to a sixth embodiment of the present invention, and FIG. 8B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 8A and 8B, the pipe 30b forming the drain discharge path on the downstream side of the drain valve 30 is connected to the pipe 42b from the upper side of the pipe 42b forming the cathode offgas discharge path. It is different in the point of joining.
As shown in FIG. 8B, the drain valve 30 is positioned above the pipe 42b, and the drain discharge path joins the pipe 42b through the communication hole 33 provided at the lower end of the drain valve 30. It has become. In this example, since the drain discharge path is joined to the pipe 42b through the communication hole 33, the pipe 30b forming the drain discharge path is omitted.

According to the fuel cell system 1, the same effects as those of the second embodiment described above can be obtained. That is, since the drain discharge path is joined to the cathode off gas discharge path from the upper side of the cathode off gas discharge path, moisture flowing through the drain discharge path flows down to the cathode off gas discharge path (pipe 42b) by gravity. Thus, the cathode offgas flowing through the cathode offgas discharge passage is suitably discharged. Therefore, the discharge of moisture flowing through the drain discharge path is favorably assisted by the flow of the cathode off gas, and the discharge performance is improved.
Further, since the drainage can be controlled by opening and closing the drain valve 30, the opening time of the drain valve 30 can be set considering only the amount of drainage of moisture. Therefore, the valve opening time of the drain valve 30 can be shortened, and the power consumption can be suppressed accordingly.

(Seventh embodiment)
FIG. 9A is a configuration diagram showing a fuel cell system according to a seventh embodiment of the present invention, and FIG. 9B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 9A and 9B, the upstream side of the drain valve 30 is that the pipe 42 b forming the cathode offgas discharge path and the pipe 30 a forming the drain discharge path are merged. Is different.

According to the fuel cell system 1, the same effects as those of the third embodiment described above can be obtained. That is, since the cathode offgas discharge path and the drain discharge path are merged on the upstream side of the drain valve 30, after the cathode offgas and the moisture are merged, the drain valve 30 controls the discharge to thereby remove the moisture. It can discharge suitably.
Further, since the moisture discharge control can be performed only by the open / close control of the drain valve 30, the control is simple, the management of the hydrogen discharge concentration is simplified, and the dilution by the diluter 43 is also suitably performed. be able to.

(Eighth embodiment)
FIG. 10A is a configuration diagram showing a fuel cell system according to an eighth embodiment of the present invention, and FIG. 10B is a schematic enlarged view showing a merging position.
In this embodiment, as shown in FIGS. 10A and 10B, an orifice 50 is provided in the drain discharge passage, and the drain valve 30 (see FIG. 1 and the like, the same applies hereinafter) is eliminated from the drain discharge passage. It is.
Further, in this example, as shown in FIG. 10B, the pipe 42b forming the cathode off-gas discharge path descends from the upper side to the downstream direction (the direction along the flow of moisture) from the pipe 30b forming the drain discharge path. It joins in an inclined manner. As a result, the cathode offgas from the cathode offgas discharge path smoothly flows into the pipe 31, and the cathode offgas flowing into the drain discharge path side has a negative pressure to favorably assist the drainage of moisture. Yes.

  According to the fuel cell system 1, the same effects as those of the fourth embodiment described above can be obtained. That is, since the drain valve 30 is eliminated, the configuration is simplified and the cost can be reduced. Further, since the drain valve 30 is eliminated, drainage control is simplified correspondingly, and power consumption can be suppressed.

In each of the above-described embodiments, the water in the drain discharge path is sucked out by using negative pressure at the joining position of the anode off-gas discharge path and the drain discharge path or the joining position of the cathode gas discharge path and the drain discharge path. A venturi portion may be provided.
By providing such a venturi part, using the negative pressure by the venturi part, moisture in the drain discharge path can be suitably sucked out to the discharge path side (anode offgas discharge path side or cathode gas discharge path side), Emission is improved. That is, good drainage is possible without increasing the purge amount. Further, since the discharge performance can be improved by using the flow velocity, the opening time of the drain valve 30 can be shortened as a result, and the power consumption can be suppressed correspondingly.

  Moreover, in each above-mentioned embodiment, the piping dimension of a joining position, the joining angle of piping, etc. can be set arbitrarily.

  Further, in each of the above-described embodiments, the case where the fuel cell system 1 is mounted on a fuel cell vehicle has been exemplified. However, for example, a fuel cell system mounted on a motorcycle, a train, or a ship may be used. Further, it may be a fuel cell system for use in stores, offices and the like.

(A) is a block diagram which shows the fuel cell system of 1st Embodiment of this invention, (b) is a model enlarged view which shows a merge position. It is a time chart which shows the operation example of the fuel cell system which concerns on 1st Embodiment. (A) is a block diagram which shows the fuel cell system of 2nd Embodiment of this invention, (b) is a model enlarged view which shows a merge position. (A) is a block diagram which shows the fuel cell system of 3rd Embodiment of this invention, (b) is a model (a) which shows a joining position, and is an enlarged view. (A) is a block diagram which shows the fuel cell system of 4th Embodiment of this invention, (b) is a model enlarged view which shows a merge position. It is a time chart which shows the example of 1 operation of the fuel cell system concerning a 4th embodiment. (A) is a block diagram which shows the fuel cell system of 5th Embodiment of this invention, (b) is a model enlarged view which shows a merge position. (A) is a block diagram which shows the fuel cell system of 6th Embodiment of this invention, (b) is a model enlarged view which shows a merge position. (A) is a block diagram which shows the fuel cell system of 7th Embodiment of this invention, (b) is a model enlarged view which shows a merge position. (A) is a block diagram which shows the fuel cell system of 8th Embodiment of this invention, (b) is a model enlarged view which shows a merge position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell stack 13 Gas-liquid separator 13a, 13b, 14a, 14b Piping (anode off-gas discharge path)
13c Piping (circulation path)
14 Purge valve 20 ECU
30 Drain valve 30a, 30b Piping (drain discharge passage)
31 Piping (joint flow path)
42 Back pressure valve 42a, 42b Piping (cathode off-gas discharge passage)
43 Diluter 50 Orifice

Claims (16)

A fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An anode offgas discharge path for discharging anode offgas from the fuel cell;
A gas-liquid separation device that is provided in the anode off-gas discharge path and separates water accompanying the anode off-gas;
A drain discharge path including a drain valve for controlling discharge of water separated by the gas-liquid separator;
A purge valve that discharges the remaining anode offgas from which moisture has been separated by the gas-liquid separator to the anode offgas discharge path,
Merging the anode off-gas discharge passage and the drain discharge passage;
A fuel cell system, wherein the discharge of moisture discharged from the drain valve is assisted using the flow of the anode off gas discharged to the anode off gas discharge path by the purge valve. A circulation path for returning the remaining anode offgas from which moisture has been separated by the gas-liquid separator to the anode gas supply side of the fuel cell;
The fuel cell system according to claim 1 , wherein the purge valve is provided in the circulation path. The fuel cell system according to claim 1 or 2 , wherein the purge valve is opened after the drain valve is opened. Combined channel and the drainage channel and the anode off-gas discharge path, the downstream side, any one of claims 1 to 3, characterized in that it is connected to a diluter for diluting the anode off-gas The fuel cell system described in 1. The anode off gas discharge path and the drain discharge path are joined downstream of the drain valve,
The said drainage passage upstream from the merging position, the fuel cell system according to any one of claims 1 to 4, characterized in that the orifice is provided. The drain discharge passage, the fuel cell system according to any one of claims 1 to 5, characterized in that from the upper side of the anode off-gas discharge path are joined to the anode off-gas discharge path. A venturi section is provided at the joining position of the anode off-gas discharge passage with the drain discharge passage to suck moisture in the drain discharge passage to the anode off-gas discharge passage side using negative pressure. The fuel cell system according to claim 6 . Wherein the anode off-gas discharge path and the drainage path, the fuel cell system according to any one of claims 1 to 4, characterized in that they are joined at the upstream side of the drain valve. A fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An anode offgas discharge path for discharging anode offgas from the fuel cell;
A gas-liquid separation device that is provided in the anode off-gas discharge path and separates water accompanying the anode off-gas;
A drain discharge path for discharging water separated by the gas-liquid separator;
An orifice provided in the drain discharge path;
A purge valve that discharges the remaining anode offgas from which moisture has been separated by the gas-liquid separator to the anode offgas discharge path,
The anode offgas discharge path and the drain discharge path are merged downstream of the orifice;
A fuel cell system, wherein the discharge of moisture discharged through the orifice is assisted by using the flow of the anode off gas discharged to the anode off gas discharge path by the purge valve. A fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An anode offgas discharge path for discharging anode offgas from the fuel cell;
A cathode offgas discharge passage for discharging the cathode offgas from the fuel cell;
A gas-liquid separation device that is provided in the anode off-gas discharge path and separates water accompanying the anode off-gas;
A drain discharge path including a drain valve for controlling discharge of water separated by the gas-liquid separator;
A back pressure valve that controls the pressure of the cathode offgas from the fuel cell ;
The cathode offgas discharge path and the drain discharge path are merged , connected to the downstream side of the combined flow path, connected to the downstream side of the anode offgas discharge path, and discharged through the anode offgas discharge path. A diluter for diluting the anode off gas,
The discharge of water discharged from the drain valve toward the diluter is assisted by using the flow of the cathode off gas discharged to the cathode off gas discharge path by the back pressure valve. Fuel cell system. The back pressure valve, the fuel cell system of claim 1 0, characterized in that the valve opening after the drain valve is opened. The cathode offgas discharge path and the drain discharge path are joined downstream of the drain valve,
The said drainage passage upstream from the merging position, the fuel cell system according to claim 1 0 or Claim 1 1, characterized in that the orifice is provided. The drain discharge passage, the fuel cell according to claims 1 0 to any one of claims 1 2, characterized in that from the upper side of the cathode off-gas discharge path are joined to the cathode off-gas discharge path system. A venturi section is provided at a position where the cathode offgas discharge path joins with the drain discharge path, and draws moisture in the drain discharge path to the anode offgas discharge path side using negative pressure. the fuel cell system according to claims 1 to 3. Wherein the cathode off-gas discharge path and the drainage path, the fuel cell system according to claim 1 0 or Claim 1 1, characterized in that they are joined at the upstream side of the drain valve. A fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An anode offgas discharge path for discharging anode offgas from the fuel cell;
A cathode offgas discharge passage for discharging the cathode offgas from the fuel cell;
A gas-liquid separation device that is provided in the anode off-gas discharge path and separates water accompanying the anode off-gas;
A drain discharge path for discharging water separated by the gas-liquid separator;
An orifice provided in the drain discharge path;
A back pressure valve that controls the pressure of the cathode offgas from the fuel cell ;
The cathode offgas discharge path and the drain discharge path are merged on the downstream side of the orifice , connected to the downstream side of the combined flow path, connected to the downstream side of the anode offgas discharge path, and the anode offgas discharge path A diluter for diluting the anode off gas discharged through
A fuel that assists the discharge of moisture discharged through the orifice toward the diluter by using the flow of the cathode offgas discharged to the cathode offgas discharge passage by the back pressure valve. Battery system.

Images