JP2009016132A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the output performance of a fuel cell. <P>SOLUTION: The fuel cell 100 includes: a fuel gas introduction port 200 constituting an inlet of a fuel gas supply manifold; and a fuel gas exhaust port 201 constituting an outlet of a fuel gas exhaust manifold used for exhausting fuel gas from the fuel cell 100. An injector 24 is disposed in the vicinity of the fuel gas introduction port 200 of a fuel gas supply piping 32. The injector 25 is disposed in the vicinity of the fuel gas exhaust port 201 of the fuel gas exhaust piping 33. When the elapsed time from the stop of the fuel cell 100 to the next start is a predetermined time or more, a control unit 110 determines that fuel gas is less than the predetermined quantity in an anode 312 surface, and when the fuel cell 100 is started, the injectors 24, 25 are alternatively opened and closed, and the fuel gas is alternatively introduced into the fuel cell 100 from the fuel gas introduction port 200 and the fuel cell exhaust port 201, thereby improving diffusion efficiency of the fuel gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to control of introduction of a reaction gas into a fuel cell.

  When the fuel cell is stopped, the fuel gas supply valve is closed and the supply of the fuel gas to the fuel cell is stopped. After the fuel cell is stopped, the oxidizing gas remaining in the oxidizing gas flow channel passes through the electrolyte membrane and leaks to the anode electrode layer side. In the anode channel, the fuel gas remaining in the anode channel and the oxidizing gas that has permeated through the electrolyte membrane react with each other to consume the fuel gas, and the amount of oxidizing gas gradually increases. When starting the fuel cell, the fuel gas supply valve arranged in the fuel gas pipe is opened, the fuel gas is supplied from the fuel tank to the anode flow path, and the oxidant gas existing in the anode flow path is consumed, and the fuel Gas spreads in the anode surface.

JP 2003-317769 A JP 2005-302563 A JP 2006-120430 A JP 2005-637112 A

  However, when the fuel cell is started, oxidizing gas may remain in the fuel gas flow path. In this case, it takes time until the fuel gas is uniformly supplied into the fuel gas flow path after the fuel gas supply valve is opened and fuel gas is introduced into the fuel cell. Further, when the fuel cell is started up, the oxidizing gas is also present in the fuel gas manifold extending in the stacking direction of the fuel cells, so that it takes time for the fuel gas to uniformly reach the entire fuel cell. Therefore, there is a problem that the output of the fuel cell is limited for a predetermined time from the start of the fuel cell.

  The present invention has been made in view of the above problems, and aims to improve the output performance of a fuel cell.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the following aspects can be realized as application examples.

[Application Example 1]
A fuel cell system according to a first application example of the present invention includes:
A fuel gas tank for storing fuel gas to be supplied to the fuel cell;
A fuel gas pipe connected to each of the fuel gas tank and the plurality of fuel gas inlets;
A plurality of introduction control valves that are installed in the fuel gas pipes corresponding to the plurality of fuel gas inlets and that control the introduction of the fuel gas from the fuel gas pipes to the fuel cell;
Information acquisition means for acquiring operation information relating to the operation state of the fuel cell;
A fuel cell system comprising: valve control means for controlling at least two introduction control valves of the plurality of introduction control valves to open and close at different timings based on the operation information.

  According to the fuel cell system of Application Example 1 described above, different timing fuel gases can be introduced into the fuel cell from at least two introduction control valves. Accordingly, the fuel gas vibrates in the fuel cell, and the diffusion of the fuel gas is promoted. Therefore, compared with the case where the fuel gas is introduced while the introduction control valve is opened when the fuel cell system is started, the time for the fuel gas to reach the entire fuel cell can be shortened, and the output performance of the fuel cell can be improved.

[Application Example 2]
A fuel cell system according to a first application example,
The fuel cell system, wherein the valve control means opens the at least two introduction control valves alternately.

  According to the fuel cell system of the application example 2, since the fuel gas can be alternately introduced into the fuel cell from the two fuel gas introduction ports, the vibration of the fuel gas can be easily generated. Therefore, the diffusion efficiency of the fuel gas into the fuel cell can be improved.

[Application Example 3]
A fuel cell system according to a first application example,
The information acquisition means acquires information on the amount of the fuel gas at the anode of the fuel cell as the operation information,
The valve control means controls the opening and closing of the at least two introduction control valves when the fuel gas in the anode is less than a predetermined amount.

  According to the fuel cell system of Application Example 3, when the fuel gas in the anode is less than a predetermined amount, the opening / closing timing of the fuel gas supply valve can be controlled. Therefore, the fuel gas diffusion efficiency can be improved when rapid diffusion of the fuel gas at the anode is required.

[Application Example 4]
A fuel cell system according to Application Example 1,
The information acquisition means includes at least one of a timer that measures an elapsed time after the fuel cell system is stopped, a hydrogen concentration sensor that measures the concentration of fuel gas at the anode, and a voltage measurement means that measures the voltage of the fuel cell. Including a fuel cell system.

  According to Application Example 4 described above, information regarding the presence of fuel gas in the anode of the fuel cell can be acquired with a simple configuration.

[Application Example 5]
A fuel cell system according to Application Example 1,
The fuel cell has a fuel gas supply manifold for supplying fuel gas to an internal flow path of the fuel cell and a fuel gas discharge manifold for discharging fuel gas from the internal flow path of the fuel cell,
Of the at least two fuel gas inlets, a first fuel gas inlet and a second fuel gas inlet are an inlet of the fuel gas supply manifold and an outlet of the fuel gas discharge manifold,
The valve control means is arranged corresponding to the first introduction control valve arranged corresponding to the inlet of the fuel gas supply manifold and the outlet of the fuel gas discharge manifold among the plurality of introduction control valves. A fuel cell system for controlling the second introduction control valve.

  According to Application Example 5 described above, the inlet of the fuel gas supply manifold and the outlet of the fuel gas discharge manifold can be used as the inlet of the fuel gas. Accordingly, the diffusion efficiency of the fuel gas can be improved without newly forming a fuel gas inlet in the fuel cell.

[Application Example 6]
A fuel cell system according to Application Example 1,
The fuel cell has a configuration in which a plurality of power generation units composed of a membrane electrode assembly and a separator are stacked,
The first fuel gas inlet is formed at one end in the stacking direction of the fuel cell,
A third fuel gas inlet different from the first fuel gas inlet and the second fuel gas inlet is formed at the other end of the fuel cell in the stacking direction and communicates with the fuel gas supply manifold. And
The valve control means is a fuel cell system that further opens and closes the first fuel gas inlet and the third inlet at different timings.

  According to Application Example 6 described above, fuel gas can be introduced at different timings from both ends of the fuel gas supply manifold. Therefore, the diffusion efficiency of the fuel gas can be improved not only in the anode plane of the fuel cell but also in the stacking direction of the fuel cell.

[Application Example 7]
A fuel cell system according to Application Example 1,
The fuel cell has a configuration in which a plurality of power generation units composed of a membrane electrode assembly and a separator are stacked,
Of the at least two fuel gas inlets, the first fuel gas inlet is formed at one end in the stacking direction of the fuel cells, and the second fuel gas inlet is the other in the stacking direction of the fuel cells. Formed at the end,
The fuel cell system, wherein the valve control means controls a first introduction control valve and a second introduction control valve associated with the first fuel gas inlet and the second fuel gas inlet.

  According to Application Example 7 described above, vibration of the fuel gas can be generated in the stacking direction of the fuel cells. Therefore, the gas diffusion efficiency in the stacking direction of the fuel cell can be improved.

[Application Example 8]
A fuel cell system according to Application Example 1,
The fuel cell has a fuel gas supply manifold for supplying fuel gas to an internal flow path of the fuel cell and a fuel gas discharge manifold for discharging fuel gas from the internal flow path of the fuel cell,
The first fuel gas inlet is an inlet of the fuel gas supply manifold or an outlet of the fuel gas discharge manifold;
The fuel cell system, wherein the second fuel gas introduction port communicates with a manifold of the fuel gas supply manifold or the fuel gas discharge manifold in which the first fuel gas introduction port is used.

  According to Application Example 8 described above, fuel gas can be introduced from both ends of either the fuel gas supply manifold or the fuel gas discharge manifold. Therefore, the gas diffusion efficiency in the stacking direction of the fuel cells can be subtracted, and the uniform distribution of the fuel gas in the manifold can be promoted.

[Application Example 9]
A fuel cell system according to Application Example 1,
The fuel cell is configured such that the inlet of the fuel gas supply manifold and the outlet of the fuel gas discharge manifold are at the same end,
The first fuel gas inlet is an inlet of the fuel gas supply manifold;
The fuel cell system, wherein the second fuel gas introduction port communicates with the fuel gas discharge manifold.

  The fuel gas introduced from the first introduction port is less likely to diffuse as it moves away from the first introduction port in the stacking direction and away from the first introduction port toward the fuel gas discharge manifold. . Therefore, according to the application example 9 described above, the fuel gas can be introduced by forming the second introduction port in a portion where the fuel gas introduced from the first introduction port is difficult to reach. The spreading time can be shortened.

[Application Example 10]
A fuel cell system according to Application Example 1,
The information acquisition means acquires the operation information when the fuel cell system is activated.

  According to Application Example 10 described above, the operation information can be acquired at the time of starting the fuel cell in which the fuel gas in the fuel gas flow path may be replaced with the oxidizing gas. Therefore, since it is not necessary to acquire operation information during normal operation, the operating load of the fuel cell system can be reduced.

  In the present invention, the various aspects described above can be applied by appropriately combining or omitting some of them.

A. First embodiment:
A1. System Configuration FIG. 1 is an explanatory diagram showing the overall configuration of a fuel cell system as a first embodiment. The fuel cell system of the embodiment is mounted as a power source in an electric vehicle driven by a motor. The fuel cell system according to the embodiment does not need to be mounted on the vehicle, and can have various configurations such as a stationary type.

  The fuel cell system includes a high-pressure fuel gas tank 10, fuel gas supply pipes 31 to 37, a high-pressure fuel gas tank 10, shut valves 20, 28 and 29, a pressure reducing valve 23, a discharge valve 22, a check valve 21, a fuel gas discharge pipe 34, A filter 40, a compressor 41, a humidifier 42, a muffler 43, a diluter 44, a pump 46, a radiator 80, a fuel cell 100, and a control unit 110 are provided.

  The fuel cell 100 includes a stacked body 101 including a separator and a membrane electrode assembly, and a pair of end plates 105 and 106 disposed at both ends of the stacked body 101 in the stacking direction. One end plate 105 includes a fuel gas inlet 200 that forms an inlet of a fuel gas supply manifold used to supply fuel gas to the fuel cell 100, and a fuel gas used to discharge fuel gas from the fuel cell 100. A fuel gas discharge port 201 constituting the outlet of the discharge manifold is formed. In addition, the other end plate 106 is used to discharge an oxidizing gas from the fuel cell 100 and an oxidizing gas introduction port 210 that constitutes an inlet of an oxidizing gas supply manifold used for supplying the oxidizing gas to the fuel cell 100. An oxidizing gas discharge port 211 that constitutes an outlet of the oxidizing gas manifold is formed. For example, hydrogen gas is used as the fuel gas.

  FIG. 2 is an exploded perspective view illustrating the configuration of a single cell of the fuel cell in the first embodiment. The fuel cell of the present embodiment is a polymer electrolyte fuel cell, and is formed by stacking single cells 300. The unit cell 300 is configured by sandwiching an electrolyte membrane 311 between an anode 312 and a cathode 313 and sandwiching this sandwich structure between separators 320 and 330 from both sides.

  The electrolyte membrane 311 is a proton-conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, and exhibits good electrical conductivity in a wet state. A layer having platinum as a catalyst or an alloy made of platinum and other metals is provided on the surface of the electrolyte membrane 311.

  Both the anode 312 and the cathode 313 are gas diffusion electrodes having gas permeability. The anode 312 and the cathode 313 can be formed of, for example, a carbon cloth woven with carbon fiber yarns, carbon paper, carbon felt, or the like.

  The separator 320 can be formed of a gas-impermeable conductive member, for example, densely formed carbon that is compressed by gas and impermeable to gas, or a press-molded metal plate. As shown in the figure, the separator 320 has six through holes 321 to 326 near the outer periphery. These holes are formed in the same manner in all the separators, and when a plurality of cells are stacked and formed as a stack, they form a manifold used for supplying and discharging fuel gas, oxidizing gas, and cooling water. . The through-hole 321 is a hole that forms a manifold that supplies oxidizing gas, and the through-hole 322 is a hole that forms a manifold that discharges oxidizing gas, so that a fuel gas discharge hole 322, a fuel gas discharge hole 322, and Call. Similarly, the through holes 323 are referred to as fuel gas supply holes 323 and fuel gas discharge holes 324, respectively, and the through holes 325 and 326 are referred to as cooling water supply holes 325 and cooling water discharge holes 326, respectively. Each hole of the separator 330 has the same configuration as the separator 320.

  As shown in FIG. 2, a flow path forming portion 327 formed so as to connect the fuel gas discharge hole 322 and the fuel gas discharge hole 322 is provided on one surface of the separator 320. Further, on one surface of the separator 330, as shown in FIG. 2, a flow path forming portion 337 that connects the cooling water supply hole 335 and the cooling water discharge hole 336 is provided. On the other surface (not shown) of the separator 330, a flow path forming portion formed so as to connect the oxidizing gas supply hole 333 and the oxidizing gas discharge hole 334 is formed.

  In the separator 320, the fuel gas supplied from the fuel gas supply hole 321 flows along the flow path forming part 327 and is used in an electrochemical reaction at the anode 312 as indicated by a thick solid line arrow in FIG. The fuel gas that has not been used for the electrochemical reaction is discharged from the fuel gas discharge hole 322. On one side (not shown) of the separator 330, the oxidizing gas also flows in the same manner as the fuel gas.

  In the separator 330, the cooling water supplied from the cooling water supply hole 335 flows along the flow path forming portion 337 formed in the separator 330 and cools the single cell 300 as shown by the thick broken line arrows in the drawing. The water is discharged from the cooling water discharge hole 336.

  Returning to FIG. The high-pressure fuel gas tank 10 is connected to the fuel gas inlet 200 of the fuel cell 100 through the fuel gas supply pipe 32, the pressure reducing valve 23, the fuel gas supply pipe 31, and the shut valve 20.

  A fuel gas discharge pipe 33 is connected to the fuel gas discharge port 201 of the fuel cell 100. A fuel gas pump 45 is installed in the fuel gas discharge pipe 33. The fuel gas discharge pipe 33 is connected to the fuel gas supply pipe 32 via the check valve 21. The fuel gas discharge pipe 33 is connected to the fuel gas discharge pipe 34 between the check valve 21 and the fuel gas pump 45. A discharge valve 22 is installed in the fuel gas discharge pipe 34. The fuel gas discharge pipe 34 is connected to a diluter 44.

  The injector 24 is disposed corresponding to the fuel gas introduction port 200. Specifically, the injector 24 is disposed near the fuel gas inlet 200 of the fuel gas supply pipe 32. The injector 25 is disposed corresponding to the fuel gas discharge port 201. Specifically, the fuel gas discharge pipe 33 is disposed in the vicinity of the fuel gas discharge port 201. The injectors 24 and 25 are electronically controlled, and open and close valves provided in the interior by power supplied from the control unit 110 to supply fuel gas. The injector can be opened and closed in a very short time compared to a general valve.

  The filter 40 and the fuel cell 100 are connected via an oxidizing gas supply pipe 35. The oxidizing gas supply pipe 35 is provided with a compressor 41 and a humidifier 42 in order from the filter 40 side. The fuel cell 100 is connected to the outside through the oxidizing gas discharge pipe 35. A muffler 43 and a diluter 44 are installed in the oxidizing gas discharge pipe 35.

  Fuel gas is supplied from the high-pressure fuel gas tank 10 to the fuel cell 100 via the fuel gas supply pipe 31 and the fuel gas supply pipe 32. Hydrogen stored in the high-pressure fuel gas tank 10 at high pressure is supplied to the fuel cell 100 by a shut-off valve 20 provided at its outlet, a decompression valve 23 connecting the fuel gas supply pipe 31 and the fuel gas supply pipe 32. The pressure of is adjusted.

  Exhaust gas from the anode (hereinafter referred to as anode off gas) is supplied to the fuel gas discharge pipe 33. The fuel gas discharge pipe 33 is branched into two on the way, one is connected to the fuel gas discharge pipe 34 for discharging the anode off gas to the outside, and the other is supplied with the fuel gas via the check valve 21. Connected to the pipe 32. While the discharge valve 22 provided in the fuel gas discharge pipe 34 is closed, the anode off gas is circulated again to the fuel cell 100 via the fuel gas supply pipe 32. By circulating the fuel gas through the fuel gas supply pipe 32, hydrogen remaining in the anode off gas without being consumed by power generation can be effectively used.

  A compressed oxidizing gas is supplied to the cathode of the fuel cell 100. The oxidizing gas is sucked from the filter 40, compressed by the compressor 41, humidified by the humidifier 42, and supplied to the fuel cell 100 from the oxidizing gas supply pipe 35. Exhaust gas from the cathode (hereinafter referred to as “cathode off gas”) is discharged to the outside through the oxidizing gas discharge pipe 35 and the muffler 43.

  The fuel cell 100 is formed with a cooling water circulation channel. The cooling water flows through the cooling pipe 37 by the pump 46, is cooled by the radiator 80, circulates through the fuel cell 100, and cools the fuel cell 100.

  The control unit 110 includes a timer (not shown) inside, and measures the elapsed time from the stop of the fuel cell 100 to the next start as operation information. The control unit 110 further controls opening and closing of the injectors 24 and 25 based on the acquired operation information. Specifically, when the elapsed time from the stop of the fuel cell 100 to the next activation is a predetermined time or more, the control unit 110 determines that the fuel gas is less than a predetermined amount in the surface of the anode 312 and When the battery 100 is started, the shut valve 28 is opened and the shut valve 29 is closed to allow the fuel gas to flow to the injector 25 and to prevent the fuel gas from leaking to the fuel gas discharge pipe 34. Are alternately opened and closed, and fuel gas is alternately introduced into the fuel cell 100 from the fuel gas inlet 200 and the fuel gas outlet 201.

  In the first embodiment, the control unit 110 determines the remaining amount of fuel gas in the surface of the anode 312 using a built-in timer. For example, the anode 312 is measured by a fuel gas concentration sensor, a voltage measurement of the fuel cell, or the like. The remaining amount of fuel gas in the surface may be determined.

  FIG. 3 is a cross-sectional view schematically showing a cross section of a single cell in the first embodiment. FIG. 3 shows an AA cross section in FIG. When the fuel cell 100 is stopped, the shut valve 20 is closed and the supply of fuel gas to the fuel cell is stopped. After the fuel cell 100 stops, the oxidizing gas remaining in the oxidizing gas channel 328 passes through the electrolyte membrane 311 and leaks to the anode 312 side. In the flow path forming portion 327, as shown in FIG. 3, the fuel gas remaining in the flow path forming portion 327 reacts with the oxidizing gas flowing through the electrolyte membrane 311 to consume the fuel gas, It is gradually replaced with oxidizing gas.

A2. Fuel gas diffusion:
FIG. 4 is a schematic diagram of the fuel cell in the first embodiment. The fuel cell 100 includes a fuel gas supply manifold 350 and a fuel gas discharge manifold 360 that extend in the stacking direction of the fuel cells.

  FIG. 4A shows the normal operation of the fuel cell 100. During the operation of the fuel cell 100, the control unit 110 maintains the injector 24 and the injector 25 in the opened state. As shown by an arrow AR1, the fuel gas flows from the fuel gas supply manifold 350 through the flow path forming portion 327 of each unit cell 300 and is supplied to the membrane electrode assembly and used for power generation. The fuel gas that has not been used for power generation flows into the fuel gas discharge manifold 360 from the fuel gas discharge hole 322, and is discharged outside the fuel cell 100 as indicated by an arrow AR2.

  On the other hand, FIG. 4B shows when the fuel cell 100 is activated. When the fuel cell 100 is activated, the control unit 110 alternately opens the injectors 24 and the injectors 25 at predetermined intervals. The fuel gas is alternately introduced into the fuel cell 100 from the fuel gas inlet 200 and the fuel gas outlet 201 as indicated by arrows AR3 and AR4.

  The introduction of the fuel gas when the fuel cell 100 is activated and the diffusion of the fuel gas in the anode surface will be described with reference to FIGS. FIG. 5 is a timing chart illustrating the injector opening / closing timing of the control unit 110 in the first embodiment. The horizontal axis of the timing chart 400 in FIG. 5 represents time t. Time t0 indicates when the fuel cell is activated. FIG. 6 is a schematic diagram for explaining the diffusion of the fuel gas in the first embodiment.

  Prior to the start of the fuel cell, the inside of the flow path forming unit 327 is replaced with the oxidizing gas from the fuel gas. That is, as shown in FIG. 6A, after a predetermined time has elapsed since the fuel cell 100 was stopped, the oxidizing gas (Air) 505 exists in the entire surface of the anode 312.

The control unit 110 opens the injector 24 at time t0. At time t0, the injector 25 is closed. When the injector 24 is opened, fuel gas is introduced from the fuel gas supply hole 321 into the flow path forming portion 327 as indicated by an arrow ar1. As a result, as shown in FIG. 6B, the oxidizing gas 505 is moved in the direction of the arrow P1 (downward in the drawing) by the fuel gas (H ₂ ) 501 within the surface of the anode 312.

The control unit 110 closes the injector 24 and opens the injector 25 at time t1 after a predetermined time has elapsed from time t0. When the injector 25 is opened, fuel gas is introduced from the fuel gas supply hole 323 into the flow path forming portion 327 as indicated by an arrow ar2. That is, the fuel gas flows in the direction opposite to the flow direction of the fuel gas during normal operation. As a result, as shown in FIG. 6C, the fuel gas 501 and the oxidizing gas 505 are moved in the direction of the arrow P2 (upward in the figure) by the fuel gas (H ₂ ) 502.

  The control unit 110 closes the injector 25 and opens the injector 24 at time t2 after a predetermined time has elapsed from time t1. In this manner, the control unit 110 alternately opens and closes the injectors 24 and the injectors 25 every predetermined time. By alternately opening and closing the two injectors 24 and 25, as shown in FIG. 6D, the fuel gas introduced into the surface of the anode 312 repeatedly moves in the directions of arrows P1 and P2. By repeating the movement of the fuel gas, the fuel gas is vibrated in the directions of arrows P1 and P2, and is uniformly diffused into the anode surface.

  The oxidizing gas present in the flow path forming unit 327 reacts with the introduced fuel gas and is consumed, and the surface of the anode 312 is replaced with the oxidizing gas from the oxidizing gas.

  FIG. 7 is a graph illustrating the pressure of the fuel gas to the fuel cell in the first embodiment. In the graph 600, the horizontal axis represents time t, and the vertical axis represents fuel gas pressure in the fuel cell. In FIG. 7, a graph 601 represents the fluctuation of the pressure of the fuel gas in the fuel cell, and the graph 602 represents the fluctuation center of the pressure of the fuel gas in the fuel cell.

  As shown in the graph 601, when the injector 24 is opened at time t0, the fuel gas is supplied into the fuel cell 100. Therefore, the pressure of the fuel gas rises to P1, and a part of the introduced fuel gas is It reacts with the oxidizing gas remaining in the fuel gas flow path forming part 327. Therefore, the pressure of the fuel gas decreases from P1 to P2.

  When the injector 24 is closed and the injector 25 is opened at time t1, the fuel gas is supplied into the fuel cell 100, so that the pressure of the fuel gas increases from P2 to P3. Similarly, a part of the introduced fuel gas reacts with the oxidizing gas remaining in the fuel gas flow path forming portion 327. Therefore, the pressure of the fuel gas decreases from P3 to P4. In this way, the fuel gas is repeatedly increased and decreased in pressure. As a result, as shown in the graph 602, the pressure of the fuel gas in the fuel cell 100 increases.

A3. Fuel gas diffusion effect:
FIG. 8 is a graph illustrating the effect of fuel gas diffusion in the first embodiment. In the graph 700, the horizontal axis represents the distance from the fuel gas inlet 200 to the fuel gas outlet 201, and the vertical axis represents the fuel gas concentration. A graph 701 shows the diffusion state of the fuel gas after a predetermined time has elapsed from the start in the fuel cell system of the first embodiment. A graph 702 shows the diffusion state of the fuel gas after a predetermined time has elapsed since the start in the conventional fuel cell system.

  As the graph 702 shows, in the conventional fuel cell system, the fuel gas is introduced from one introduction port. Therefore, in the vicinity of the fuel gas inlet 200, the concentration of the fuel gas is almost 100%. However, since no vibration of the fuel gas occurs, the diffusion of the fuel gas in the fuel cell 100 is not promoted, and the fuel gas does not flow at the boundary X between the existing oxidizing gas and the fuel gas introduced into the flow path forming unit 327. Concentration drops rapidly. That is, local fuel gas deficiency occurs in the surface of the anode 312. Local depletion of fuel gas in the surface of the anode 312 is not preferable because it causes damage to the anode and the electrolyte membrane and decreases the power generation efficiency of the fuel cell.

  On the other hand, in the first embodiment, as shown by the graph 701, the fuel gas is introduced from the two inlets (the fuel gas inlet 200 and the fuel gas outlet 201). Therefore, as shown in the graph 701, the fuel gas concentrations at the fuel gas inlet 200 and the fuel gas outlet 201 are approximately the same. Further, in the first embodiment, since the fuel gas is alternately introduced from the fuel gas inlet 200 and the fuel gas outlet 201, the vibration of the fuel gas occurs in the fuel cell 100 as described above, and the diffusion occurs. Promoted. Therefore, as shown in the graph 701, the fuel gas spreads also in the intermediate portion between the fuel gas inlet 200 and the fuel gas outlet 201. Therefore, local fuel gas deficiency is suppressed in the surface of the anode 312.

  According to the fuel cell system of the first embodiment described above, the introduction timing of the fuel gas from the two fuel gas introduction ports to the fuel cell can be controlled. Thereby, the vibration of the fuel gas can be generated in the fuel cell, and the diffusion of the fuel gas can be promoted. Therefore, local deficiency of the fuel gas in the anode surface at the start of the fuel cell can be reduced, damage to the anode and electrolyte membrane can be suppressed, and the power generation efficiency of the fuel cell can be improved.

  In the first embodiment, since the fuel gas can be alternately introduced from the two fuel gas inlets, the vibration of the fuel gas can be generated easily and quickly. Therefore, the fuel gas diffusion efficiency can be further improved.

  In the first embodiment, the control unit measures the elapsed time from the stop to the start of the fuel cell, and can determine the remaining amount of anode in the anode surface based on the elapsed time. Therefore, with a simple configuration, various controls relating to the opening and closing of the valve based on the remaining amount of the anode, for example, highly accurate control such as the introduction time of the fuel gas from the plurality of fuel gas inlets can be performed.

B. Second embodiment:
In the second embodiment, a fuel cell in which an inlet of a fuel gas manifold as a fuel gas inlet is formed at one end in the stacking direction of the fuel cell and a fuel gas inlet connected to the fuel gas manifold is formed at the other end. The system will be described. In the second embodiment, each component having the same reference numeral as that in the first embodiment has the same configuration and function as each component described in the first embodiment.

B1. About fuel gas diffusion:
FIG. 9 is a schematic diagram of a fuel cell in the second embodiment. The fuel cell 101a of the second embodiment includes a stacked body 101 in which a plurality of single cells are stacked, an end plate 105, and an end plate 106a. In the laminate 101, a fuel gas supply manifold 350 and a fuel gas discharge manifold 360 are configured by the through holes formed in each single cell and the fuel gas introduction port 200 and the fuel gas discharge port 201 formed in the end plate 105. ing.

  A through hole 202 is formed in the end plate 106 a so as to be connected to the fuel gas supply manifold 350. A fuel gas pipe connected to the high-pressure fuel gas tank 10 is connected to the through hole 202. The through hole 202 is used as a fuel gas inlet for introducing fuel gas into the fuel gas supply manifold. Hereinafter, the through hole 202 is referred to as a fuel gas inlet 202.

  An injector 26 is disposed near the fuel gas inlet 202 of the fuel gas pipe connected to the fuel gas inlet 202.

  In the second embodiment, when the fuel cell is started, the control unit 110 alternately opens the injectors 24 and the injectors 26 at predetermined intervals. The fuel gas is alternately introduced into the fuel gas supply manifold 350 from the fuel gas inlet 200 and the fuel gas inlet 202.

  In the fuel gas supply manifold 350 as well, the fuel gas is replaced with the oxidizing gas, similarly to the flow path forming portion 327. Therefore, by alternately introducing the fuel gas from the fuel gas inlets 200 and 202 formed at both ends of the fuel gas supply manifold 350, the fuel gas can be vibrated in the fuel gas supply manifold 350.

  According to the fuel cell system of the second embodiment described above, the fuel gas can be vibrated by alternately introducing the fuel gas from both ends in the fuel gas supply manifold 350. Therefore, local deficiency of the fuel gas in the fuel gas supply manifold 350 can be reduced, and the fuel gas can be uniformly diffused in the stacking direction.

C. Third embodiment:
In the third embodiment, an inlet of a fuel gas supply manifold as a fuel gas inlet is formed at one end in the stacking direction of the fuel cells, and a fuel gas discharge manifold 360 is formed at the other end separately from the outlet of the fuel gas discharge manifold. A fuel cell system in which a fuel gas inlet connected to is formed will be described. In the third embodiment, each component having the same reference numeral as that in the first embodiment has the same configuration and function as each component described in the first embodiment.

C1. About fuel gas diffusion:
FIG. 10 is a schematic diagram of a fuel cell according to the third embodiment. The fuel cell 101b of the third embodiment includes a stacked body 101 in which a plurality of single cells are stacked, an end plate 105, and an end plate 106b. In the laminate 101, a fuel gas supply manifold 350 and a fuel gas discharge manifold 360 are configured by the through holes formed in each single cell and the fuel gas introduction port 200 and the fuel gas discharge port 201 formed in the end plate 105. ing.

  A through hole 203 is formed in the end plate 106 b so as to be connected to the fuel gas discharge manifold 360. A fuel gas pipe connected to the high-pressure fuel gas tank 10 is connected to the through hole 203. The through hole 203 is used as a fuel gas inlet for introducing fuel gas into the fuel gas discharge manifold. Hereinafter, the through hole 203 is referred to as a fuel gas introduction port 203.

  An injector 27 is disposed near the fuel gas inlet 203 of the fuel gas pipe connected to the fuel gas inlet 203.

  In the third embodiment, when the fuel cell is activated, the control unit 110 alternately opens the injectors 24 and the injectors 27 at predetermined intervals. The fuel gas is supplied from the fuel gas inlet 200 to the fuel gas supply manifold 350 and is alternately introduced from the fuel gas inlet 203 to the fuel gas discharge manifold 360.

  Since the vicinity of the end plate 106b of the fuel gas discharge manifold is separated from the fuel gas inlet 200, the fuel gas introduced from the fuel gas inlet 200 is difficult to reach. Accordingly, fuel gas diffusion is assisted by introducing the fuel gas from the end plate 106b side in the vicinity of the end plate 106b of the fuel gas discharge manifold 360 where the fuel gas is difficult to reach.

  According to the fuel cell system of the third embodiment described above, the fuel gas can be introduced from the portion where the fuel gas introduced from the fuel gas inlet 200 of the fuel gas supply manifold 350 is difficult to reach. Therefore, the diffusion of the fuel gas can be assisted and the local fuel gas deficiency can be reduced.

D. Fourth embodiment:
In the fourth embodiment, a fuel cell system capable of introducing fuel gas from the fuel gas inlet 200, the fuel gas outlet 201, and the fuel gas inlet 202 will be described.

D1. About fuel gas diffusion:
FIG. 11 is a schematic diagram of a fuel cell in the fourth embodiment. The fuel cell 101a of the second embodiment includes a stacked body 101 in which a plurality of single cells are stacked, an end plate 105, and an end plate 106a. In the laminate 101, a fuel gas supply manifold 350 and a fuel gas discharge manifold 360 are configured by the through holes formed in each single cell and the fuel gas introduction port 200 and the fuel gas discharge port 201 formed in the end plate 105. ing.

  A through hole 202 is formed in the end plate 106 a so as to be connected to the fuel gas supply manifold 350. A fuel gas pipe connected to the high-pressure fuel gas tank 10 is connected to the through hole 202. The through hole 202 is used as a fuel gas inlet for introducing fuel gas into the fuel gas supply manifold. Hereinafter, the through hole 202 is referred to as a fuel gas inlet 202.

  An injector 24 is disposed corresponding to the fuel gas inlet 200, an injector 25 is disposed corresponding to the fuel gas outlet 201, and an injector 26 is disposed corresponding to the fuel gas inlet 202.

  In the fourth embodiment, when the fuel cell is started, the control unit 110 alternately opens the injectors 24 and the injectors 25 at a predetermined interval. The injector 26 opens and closes simultaneously with the injector 25. The fuel gas is alternately introduced into the surface of the anode 312 from the fuel gas inlet 200 and the fuel gas outlet 201 and is alternately supplied to the fuel gas supply manifold 350 from the fuel gas inlet 200 and the fuel gas inlet 202. be introduced.

  According to the fuel cell system of the fourth embodiment described above, the fuel gas can be vibrated in the fuel cell supply manifold extending in the anode plane and in the stacking direction, and the diffusion efficiency of the fuel gas can be improved.

E. Variations:
(1) In each of the above-described embodiments, the fuel gas is alternately introduced into the fuel cell from the two fuel gas inlets by opening and closing the injector. For example, the fuel gas pump disposed on the fuel gas pipe The fuel gas may be vibrated by alternately rotating the rotation direction in the forward direction and the reverse direction.

  FIG. 12 is an explanatory diagram illustrating a fuel cell system according to a modification. The fuel gas pump 45 sends fuel gas into the fuel cell through the fuel gas supply pipe 32 and the fuel gas inlet 200 while rotating in the forward direction, as indicated by the thick arrow AR10, and rotates in the reverse direction. During this time, the fuel gas is sent into the fuel cell via the fuel gas discharge pipe 33 and the fuel gas discharge port 201.

  According to the above-described modification, the fuel gas can be alternately introduced into the fuel cell 100 from the fuel gas inlet 200 and the fuel gas outlet 201. Therefore, vibration of the fuel gas can be generated in the fuel cell without disposing the injector.

(2) In the first embodiment described above, the injector 24 and the injector 25 are alternately opened and closed, and the fuel gas is alternately introduced from the inlet of the fuel gas supply manifold 350 and the outlet of the fuel gas discharge manifold. For example, without providing the injector, the shut valve 20 and the discharge valve 22 may be alternately opened and closed to cause vibration of the fuel gas in the fuel cell.

(3) In the fourth embodiment described above, it is formed at the inlet of the fuel gas supply manifold 350 formed at one end in the stacking direction of the fuel cells and at the other end in the stacking direction of the fuel cells and connected to the fuel gas discharge manifold. Although the fuel gas is introduced from the fuel gas introduction port, for example, in addition to this, the fuel gas may be introduced from the outlet of the fuel gas discharge manifold.

(4) In the first to third embodiments, two fuel gas inlets are used, and in the fourth embodiment, three fuel gas inlets are used. For example, four or more fuel gas inlets are introduced. I get sick even if I introduce fuel gas through my mouth.

(5) In the first to fourth embodiments, the fuel gas is alternately introduced from the plurality of fuel gas inlets. However, the fuel gas may not be alternately introduced. The timing of fuel gas introduction from each fuel gas inlet may be shifted.

(6) In the above-described embodiment, the fuel cell is configured by stacking a plurality of single cells each having a membrane electrode assembly sandwiched by a pair of separators. A power generation unit having an electrode assembly and a three-layer stacked separator may be alternately stacked.

(7) In the fuel cell system, when three or more fuel gas introduction ports are formed, the fuel gas introduction timing from each fuel gas introduction port may be shifted.

Although various embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to these embodiments and can take various configurations without departing from the spirit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the whole structure of the fuel cell system as 1st Example. The disassembled perspective view which illustrates the structure of the single cell of the fuel cell in 1st Example. Sectional drawing which shows typically the cross section of the single cell in 1st Example. The schematic diagram of the fuel cell in 1st Example. The timing chart which illustrates the injector opening-and-closing timing in 1st Example. The schematic diagram explaining the spreading | diffusion of the fuel gas in 1st Example. The graph which illustrates about the pressure of the fuel gas to the fuel cell in 1st Example. The graph which illustrates the effect of diffusion of fuel gas in the 1st example. The schematic diagram of the fuel cell in 2nd Example. The schematic diagram of the fuel cell in 3rd Example. The schematic diagram of the fuel cell in 4th Example. Explanatory drawing which illustrates the fuel cell system in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... High pressure fuel gas tank 20 ... Shut valve 21 ... Check valve 22 ... Fuel gas discharge hole 22 ... Discharge valve 23 ... Pressure-reducing valve 24, 25, 26, 27 ... Injector 28, 29 ... Shut valve 31, 32 ... Fuel gas supply Pipe 33 ... Fuel gas discharge pipe 34 ... Fuel gas discharge pipe 35 ... Oxidation gas supply pipe 35 ... Oxidation gas discharge pipe 37 ... Pipe 40 ... Filter 41 ... Compressor 42 ... Humidifier 43 ... Muffler 44 ... Diluter 45 ... Fuel gas pump 46 ... Pump 80 ... Radiator 100 ... Fuel cell 101 ... Laminated body 101a ... Fuel cell 101b ... Fuel cell 105, 106, 106a, 106b ... End plate 110 ... Control unit 200 ... Fuel gas inlet 201 ... Fuel gas outlet 202 ... Fuel Gas inlet 203 ... Fuel gas inlet 210 ... Acid Gas inlet 211 ... Oxidizing gas outlet 300 ... Single cell 311 ... Electrolyte membrane 312 ... Anode 313 ... Cathode 320 ... Separator 321 ... Fuel gas supply hole 321 ... Fuel gas discharge hole 322 ... Fuel gas discharge hole 323 ... Fuel gas supply hole 324 ... Fuel gas discharge hole 325 ... Cooling water supply hole 326 ... Cooling water discharge hole 327 ... Flow path forming part 328 ... Oxidation gas flow path 330 ... Separator 333 ... Oxidation gas supply hole 334 ... Oxidation gas discharge hole 335 ... Cooling water supply Hole 336 ... Cooling water discharge hole 337 ... Flow path forming part 350 ... Fuel gas supply manifold 360 ... Fuel gas discharge manifold 400 ... Timing chart 501 ... Fuel gas 505 ... Oxidation gas 600 ... Graph 601 ... Graph 602 ... Graph 700 ... Graph 701 ... graph 702 ... graph

Claims (10)

A fuel cell system,
A fuel cell having a plurality of fuel gas inlets used for introducing fuel gas;
A fuel gas source for storing fuel gas to be supplied to the fuel cell;
A fuel gas pipe connected to each of the fuel gas source and the plurality of fuel gas inlets;
A plurality of introduction control valves that are installed in the fuel gas pipes corresponding to the plurality of fuel gas inlets and that control the introduction of the fuel gas from the fuel gas pipes to the fuel cell;
Information acquisition means for acquiring operation information relating to the operation state of the fuel cell;
A fuel cell system comprising: valve control means for controlling at least two introduction control valves of the plurality of introduction control valves to open and close at different timings based on the operation information. The fuel cell system according to claim 1, wherein
The fuel cell system, wherein the valve control means opens the at least two introduction control valves alternately. The fuel cell system according to claim 1 or 2, wherein
The information acquisition means acquires information on the amount of the fuel gas at the anode of the fuel cell as the operation information,
The valve control means controls the opening and closing of the at least two introduction control valves when the fuel gas in the anode is less than a predetermined amount. The fuel cell system according to claim 3, wherein
The information acquisition means includes at least one of a timer that measures an elapsed time after the fuel cell system is stopped, a hydrogen concentration sensor that measures the concentration of fuel gas at the anode, and a voltage measurement means that measures the voltage of the fuel cell. Including a fuel cell system. A fuel cell system according to any one of claims 1 to 4, wherein
The fuel cell has a fuel gas supply manifold for supplying fuel gas to an internal flow path of the fuel cell and a fuel gas discharge manifold for discharging fuel gas from the internal flow path of the fuel cell,
Of the at least two fuel gas inlets, a first fuel gas inlet and a second fuel gas inlet are an inlet of the fuel gas supply manifold and an outlet of the fuel gas discharge manifold,
The valve control means is arranged corresponding to the first introduction control valve arranged corresponding to the inlet of the fuel gas supply manifold and the outlet of the fuel gas discharge manifold among the plurality of introduction control valves. A fuel cell system for controlling the second introduction control valve. The fuel cell system according to claim 5, wherein
The fuel cell has a configuration in which a plurality of power generation units composed of a membrane electrode assembly and a separator are stacked,
The first fuel gas inlet is formed at one end in the stacking direction of the fuel cell,
A third fuel gas inlet different from the first fuel gas inlet and the second fuel gas inlet is formed at the other end of the fuel cell in the stacking direction and communicates with the fuel gas supply manifold. And
The valve control means is a fuel cell system that further opens and closes the first fuel gas inlet and the third inlet at different timings. A fuel cell system according to any one of claims 1 to 4, wherein
The fuel cell has a configuration in which a plurality of power generation units composed of a membrane electrode assembly and a separator are stacked,
Of the at least two fuel gas inlets, the first fuel gas inlet is formed at one end in the stacking direction of the fuel cells, and the second fuel gas inlet is the other in the stacking direction of the fuel cells. Formed at the end,
The fuel cell system, wherein the valve control means controls a first introduction control valve and a second introduction control valve associated with the first fuel gas inlet and the second fuel gas inlet. The fuel cell system according to claim 7, wherein
The fuel cell has a fuel gas supply manifold for supplying fuel gas to an internal flow path of the fuel cell and a fuel gas discharge manifold for discharging fuel gas from the internal flow path of the fuel cell,
The first fuel gas inlet is an inlet of the fuel gas supply manifold or an outlet of the fuel gas discharge manifold;
The fuel cell system, wherein the second fuel gas introduction port communicates with a manifold of the fuel gas supply manifold or the fuel gas discharge manifold in which the first fuel gas introduction port is used. The fuel cell system according to claim 7, wherein
The fuel cell is configured such that the inlet of the fuel gas supply manifold and the outlet of the fuel gas discharge manifold are at the same end,
The first fuel gas inlet is an inlet of the fuel gas supply manifold;
The fuel cell system, wherein the second fuel gas introduction port communicates with the fuel gas discharge manifold. A fuel cell system according to any one of claims 1 to 9,
The information acquisition means acquires the operation information when the fuel cell system is activated.

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