JP4415678B2 - Fuel cell - Google Patents

Description

  The present invention relates to a technology of a fuel cell system.

  In a fuel cell system using an ion exchange membrane as an electrolyte, appropriate water management is required for the entire fuel cell. This is because when the moisture content in the ion exchange membrane becomes excessively small, the membrane resistance increases. On the other hand, when the moisture content becomes excessively high, it becomes difficult to supply the reaction gas and the electrode reaction is hindered. A technique for effectively performing appropriate water management for such a problem is also disclosed. For example, as disclosed in Patent Document 1, it is a method of discharging excessively generated water from a reaction gas channel via a porous layer.

Japanese Patent Laid-Open No. 9-312166 Japanese National Patent Publication No. 11-508726

  However, in such a method, when the generated water passes through the porous layer, it is expected that impurities contained in the generated water are accumulated in the porous layer. The impurities accumulated in this way become a factor that obstructs the discharge of the produced water by closing the porous layer. Furthermore, such a problem is not limited to a fuel cell system using an ion exchange membrane, and may occur in a fuel cell that drains water from a reaction gas passage using a porous material.

  The present invention has been made to solve the above-described problems in the prior art, and provides a technique for reducing blockage of the porous material in a fuel cell that drains the reaction gas passage using the porous material. The purpose is to do.

The fuel cell of the present invention comprises
Electrolyte,
First and second electrodes having a catalyst layer, wherein the catalyst layer is joined to the electrolyte;
A first separator having at least a portion of a porous portion formed of a porous material and provided in contact with the first electrode;
With
In the fuel cell, at least a part of the reaction channel is formed at a position in contact with the porous portion and the first electrode, and at a position in contact with the porous portion and not in contact with the first electrode. It is configured to form a flow path for environmental control,
The fuel cell further includes a clogging reduction unit that reduces clogging of the porous part due to impurities entering the porous part from at least one of the reaction channel and the environment control channel. .

  Since the fuel cell of the present invention includes a clogging reduction part that reduces clogging of the porous part due to impurities entering the porous part, water generated excessively in the reaction channel can be smoothly passed through the porous part. It can be drained. As a result, it is possible to reduce the deterioration in the performance of the fuel cell due to flooding.

  Here, “flooding” is a phenomenon in which the liquid water generated excessively in the catalyst layer of the fuel cell prevents the reaction gas from spreading to the catalyst layer, thereby reducing the performance of the fuel cell. “Impurity” means a tangible substance other than the reaction gas, such as sand, dust, dust, etc. entering from the outside of the fuel cell system, or separator inside the fuel cell system such as carbon powder, metal powder, fiber scraps, etc. There are things that occur in

  In the fuel cell, the electrolyte may be an ion exchange membrane. A fuel cell using an ion exchange membrane as an electrolyte has a remarkable effect because its performance varies greatly depending on the suitability of water management.

  In the fuel cell, the clogging reduction unit may include a filter that filters a reaction gas supplied to at least one of the reaction channel and the environment control channel. This reduces the amount of impurities that flow into the reaction flow path and the environmental control flow path, thus reducing the amount of impurities that enter the porous portion from the reaction flow path and the environmental control flow path, and blocking them. Can be reduced.

  In the fuel cell, the filter may perform a filtration process including a filtration by an ion exchange process. In this way, impurities present as ions in the reaction gas can also be filtered. Furthermore, ions as impurities generated inside the fuel cell can also be reduced.

  In the fuel cell, the ion exchange treatment may include a cation exchange treatment. Since the cation impurities cause a decrease in the cation conductivity in the cation exchange membrane, this can also reduce the performance deterioration of the fuel cell due to the deposition of the cation impurities on the cation exchange membrane.

  The fuel cell may be configured such that an oxidizing gas is supplied to the reaction channel. Since the reaction flow channel to which the oxidizing gas is supplied generates more generated water than the flow channel to which the fuel gas is supplied, the effect of reducing the blockage of the porous portion is remarkably exhibited.

  In the fuel cell, the first separator may be configured such that a refrigerant flow path for flowing a refrigerant for cooling the fuel cell is formed.

  In the fuel cell, the fuel cell may be configured such that the environment control flow path is connected to the upstream side of the reaction flow path. In this way, the humidifier can be deleted from the air supply system, and the burden on the cooling system can be reduced.

The fuel cell system of the present invention comprises an ion exchange membrane, a first electrode having a catalyst layer and the catalyst layer joined to the ion exchange membrane, and a porous portion formed of a porous material. A fuel cell comprising: a first separator provided at least in part and in contact with the first electrode;
A reaction gas supply unit for supplying a reaction gas to the fuel cell;
With
In the fuel cell, at least a part of the reaction channel is formed at a position in contact with the porous portion and the first electrode, and at a position in contact with the porous portion and not in contact with the first electrode. It is configured to form a flow path for environmental control,
The fuel cell system operates the reaction gas supply unit so as to reduce clogging of the porous part due to impurities entering the porous part from at least one of the reaction flow path and the environmental control flow path. It has a specific operation mode.

  Since the fuel cell system of the present invention has a specific operation mode for reducing the blockage of the porous portion, it eliminates or reduces the use of parts that are premised on replacement, for example, a device for filtering impurities. be able to. As a result, it is possible to reduce a decrease in the performance of the fuel cell due to flooding caused by the blockage of the porous portion while suppressing an increase in the maintenance burden of the fuel cell system.

  In addition, you may comprise so that the above-mentioned blockage reduction part may be equipped with respect to this fuel cell system. In this way, the blockage of the porous portion can be suppressed in advance by the blockage reducing portion, and even if the blockage occurs, the blockage can be reduced by a specific operation mode. Deterioration can be suppressed more reliably.

  In the fuel cell system, the specific operation mode may be executed when power generation of the fuel cell is stopped. In this way, the clogging of the porous portion can be reduced without hindering the power generation of the fuel cell.

  In the fuel cell system, the specific operation mode requires a supply amount of a reaction gas from the reaction gas supply unit to at least one of the reaction channel and the environment control channel for power generation. You may make it be the mode which increases more than supply amount. By so doing, the impurities staying in the reaction gas channel can be discharged to the outside, so that the entry of impurities into the porous portion can be suppressed.

  In the fuel cell system, the fuel cell includes a first valve for controlling a flow rate downstream of one of the reaction flow path and the environment control flow path, and the specific operation mode is The reaction gas supply unit and the first valve are controlled so that the other flow from the flow path on the side where the first valve is provided out of the reaction flow path and the environmental control flow path. The mode may be a mode in which the reaction gas flows through the path via the porous portion. In this way, the pressure difference between the reaction flow path and the environmental control flow path can be controlled by the first valve, so that the flow path on the side where the valve of the first valve is equipped is changed to the other flow path. Impurities can be discharged more reliably into the flow path.

In the fuel cell system, the fuel cell may be configured such that the environmental control flow path is connected in series to the upstream side of the reaction flow path. In this configuration, the fuel cell further includes a second valve for controlling a flow rate between the environmental control flow path and the reaction flow path,
In the specific operation mode, the reaction gas supply unit and the second valve are controlled, and the reaction gas flows from the environment control channel to the reaction channel via the porous unit. You may make it be a mode to make it.

  Thus, if the reaction gas is caused to flow in the direction opposite to the direction of drainage of the porous portion during power generation of the fuel cell, impurities can be effectively discharged from the porous portion. The valves include a wide range of valves such as a shut-off valve and a flow rate control valve as long as they can control the flow rate and the pressure difference between the upstream side and the downstream side so as to generate a back flow in the porous portion.

The fuel cell system further includes a pressure difference measuring unit that measures a difference between the pressure of the reaction channel and the pressure of the environment control channel, and the measurement is performed when a predetermined amount of the reaction gas is supplied. The specific operation mode may be activated only when the pressure difference is greater than the first threshold,
Alternatively, in the fuel cell system, the specific operation mode is a mode that automatically stops when the measured pressure difference becomes smaller than a second threshold value when a predetermined amount of the reaction gas is supplied. Alternatively, it may be configured to start and stop under the above conditions. The first threshold value may be the same as the second threshold value.

  In this way, the pressure for reducing the clogging is applied to the environmental control channel only when the porous portion is clogged to some extent. Damage) can be suppressed. Furthermore, the energy required for operation can be reduced.

In the fuel cell system, the fuel cell system further includes a pressure difference measuring unit that measures a difference between the pressure of the reaction channel and the pressure of the environment control channel,
The specific operation mode may be a mode in which the second valve and the reaction gas supply unit are operated so that the measured pressure difference does not exceed a third threshold value.

  In this way, excessive pressurization of the environmental control flow path can be prevented, so that damage to the fuel cell due to excessive pressurization can be suppressed.

  The present invention can be realized in various modes. For example, a fuel cell control device, a hybrid power supply system and its control device and control method, a mobile body (for example, a fuel cell vehicle) including these systems, and Aspects of the control method, a computer program for realizing the functions of the system or method, a recording medium storing the computer program, a data signal including the computer program and embodied in a carrier wave, and a power supply method Can be realized.

Next, embodiments of the present invention will be described in the following order based on examples.
A. Configuration of a fuel cell system in an embodiment of the present invention:
B. Purification treatment of porous portion in the embodiment of the present invention:
C. Variations:

A. Configuration of a fuel cell system in an embodiment of the present invention:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system 10 in the first embodiment. The fuel cell system 10 includes a fuel cell 100, a hydrogen gas supply system for supplying hydrogen gas to the fuel cell, an air supply system for supplying air to the fuel cell, and a coolant for supplying fuel to the fuel cell. And a controller 600 for controlling them.

  The fuel cell 100 is a polymer electrolyte fuel cell having a plurality of stacked cells (described later), a fuel cell external pipe 434, and a shutoff valve 436. The plurality of stacked cells include three introduction paths 330in, 432in, 530in and three derivations for supplying fluid from the hydrogen gas supply system, the air supply system, and the coolant supply system to the internal flow path of each cell. The paths 330out, 430out, and 530out, and the introduction path 430in and the outlet path 432out connected to the fuel cell external pipe 434 are formed as holes that communicate with each other. In this embodiment, the shut-off valve 436 corresponds to a “second valve” in the claims.

  The hydrogen supply system includes a hydrogen tank 302, a pressure reducing valve 304, and a flow rate control valve 306. The hydrogen tank 302 stores hydrogen gas at a high pressure. The pressure reducing valve 304 reduces the hydrogen stored at high pressure to a predetermined pressure. The flow control valve 306 adjusts the flow rate of the decompressed hydrogen gas.

  The hydrogen supply system supplies hydrogen gas whose pressure and flow rate are adjusted to the hydrogen gas introduction path 330 in of the fuel cell 100 through the hydrogen gas supply pipe 310. The hydrogen gas introduced from the hydrogen gas introduction passage 330in is led out from the hydrogen gas lead-out passage 330out after being used for an electrochemical reaction in the hydrogen gas passage 330. The gas led out from the hydrogen gas lead-out path 330out is discharged to the outside via the shut-off valve 392 and the hydrogen gas discharge pipe 390.

  The air supply system includes an air blower 402 that sucks air, an air supply pipe 410 that supplies air to the fuel cell 100, and an air discharge pipe 490 that discharges reacted air from the fuel cell 100.

  The air supply system supplies air to the environment control air introduction path 432 in of the fuel cell 100 via the air supply pipe 410. The air introduced from the environment control air introduction path 432in is led out from the environment control air lead-out path 432out communicating after being humidified in the environment control air flow path 432. A method of humidification will be described later. A pressure gauge 620 is connected to the environment control air flow path 432.

  The air led out from the environment control air lead-out path 432out is supplied to the reaction air introduction path 430in communicating through the fuel cell external pipe 434. The fuel cell external pipe 434 includes a shutoff valve 436 for controlling the flow of air supplied to the reaction air introduction path 430in.

  The air introduced from the reaction air introduction passage 430in is led out from the reaction air lead-out passage 430out after being used for the electrochemical reaction in the reaction air passage 430. The reacted air led out from the reaction air lead-out path 430out is discharged to the outside through the air discharge pipe 490. A pressure gauge 610 is connected to the reaction air flow path 430.

  The coolant supply system includes a circulation pump 502, a heat exchanger 504, and a coolant supply pipe 510. The circulation pump 502 supplies the coolant cooled by the heat exchanger 504 to the coolant flow path 530 formed inside the fuel cell 100, and supplies the coolant discharged from the fuel cell 100 to the heat exchanger 504. Supply. This circulation is performed via the coolant supply pipe 510.

  As described above, each cell is provided with the hydrogen gas passage 330 through which hydrogen gas flows, the coolant passage 530 through which the coolant flows, and the air passage through which air flows. The air flow path includes an environment control air flow path 432, a fuel cell external pipe 434, a shutoff valve 436, and a reaction air flow path 430. The air flow path will be described in detail later.

  FIG. 2 is an exploded perspective view showing the configuration of the cell 110 of the fuel cell 100. The cell 110 includes an MEA (Membrane-Electrode Assembly) 120 and two separators 130 and 140. The MEA 120 is sandwiched between two separators 130 and 140. The cells 110 are stacked inside the fuel cell 100.

  The MEA 120 has an electrolyte membrane 122, a hydrogen electrode 126, and an oxygen electrode 124. The electrolyte membrane 122 is sandwiched between two electrodes 124 and 126. The two electrodes 124 and 126 include a gas diffusion layer for diffusing hydrogen gas or oxygen in the air.

  The hydrogen electrode side separator 130 and the oxygen electrode side separator 140 include a hydrogen gas introduction path 330in, a hydrogen gas extraction path 330out, an environment control air introduction path 432in, an environment control air extraction path 432out, and reaction air. An introduction path 430in, a reaction air outlet path 430out, a coolant introduction path 530in, and a coolant outlet path 530out are formed. These introduction paths 330in, 430in, 432in, and 530in and lead-out paths 330out, 430out, 432out, and 530out are formed at positions and sizes that communicate with each other when the plurality of cells 110 are stacked.

  In the hydrogen electrode side separator 130 and the oxygen electrode side separator 140, an environment control air flow path 432, a reaction air flow path 430, and a hydrogen gas flow path 330 are further formed. These flow paths 432, 430, and 330 are formed as a plurality of flow paths that are formed in parallel to the direction in which the fluid flows. The reason why the plurality of flow paths are formed is to allow the fluid to flow more uniformly over the hydrogen electrode 126, the oxygen electrode 124, and a porous portion described later.

  FIG. 3 is an explanatory diagram showing how air flows in each flow path formed in the oxygen electrode side separator 140. FIG. 3A is a view of the oxygen electrode side separator 140 viewed from the S1 direction (FIG. 2). FIG. 3B is a view of the oxygen electrode side separator 140 viewed from the S2 direction. A portion P surrounded by a dotted line in FIG. 3 is made of a porous material as compared with other portions of the oxygen electrode side separator 140 so that air and water can pass therethrough. In this specification, this portion is called a porous portion P, and the other portion is called a dense portion.

  The air supplied from the outside flows in the flow paths formed in the oxygen electrode side separator 140 as follows. The air is introduced from the environment control air introduction path 432in, and flows through the environment control air flow path 432 (FIG. 3A) formed at a position in contact with the porous portion P. The air that has passed through the environment control air flow path 432 is led out from the environment control air lead-out path 432out.

  The air led out from the environment control air lead-out path 432out is supplied to the reaction air introduction path 430in via the fuel cell external pipe 434. The air supplied to the reaction air introduction passage 430in flows through the reaction air passage 430 (FIG. 3B) and is supplied to the electrochemical reaction. The reacted air subjected to the electrochemical reaction is exhausted from the cell 110 through the reaction air lead-out path 430out.

  FIG. 4 is an explanatory view showing a state in which the reaction product water moves through the porous part P. This explanatory view is a view of a stack of two stacked cells 110 as viewed from the side. As can be seen from FIG. 4, the porous portion P is disposed between the reaction air flow path 430 and the environment control air flow path 432.

  The reaction air channel 430 is formed at a position in contact with the gas diffusion layer of the oxygen electrode 124 and the porous portion P. The environment control air flow path 432 is formed at a position in contact with the porous portion P and not in contact with the gas diffusion layer of the oxygen electrode 124.

  Reaction product water generated by MEA is discharged from the gas diffusion layer of the oxygen electrode 124. The reaction product water is absorbed by the porous portion P and discharged to the environment control air flow path 432 side. The reaction product water discharged to the environment control air flow path 432 side is vaporized in the air passing through the environment control air flow path 432. By this vaporization, the air passing through the environmental control air flow path 432 is humidified and the oxygen electrode side separator 140 is cooled.

  Thus, this structure has the advantage that a humidifier can be deleted from an air supply system. Furthermore, since the oxygen electrode side separator 140 is also cooled by the latent heat of vaporization of generated water generated in the porous portion P, there is an advantage that the burden on the cooling system can be reduced.

  However, when the air supplied from the air supply system contains impurities, there is a possibility that impurities absorbed together with the reaction product water are accumulated in the porous portion P, and the porous portion P is clogged. . The present embodiment can solve this problem as follows.

B. Purification treatment of porous portion in the embodiment of the present invention:
FIG. 5 is a flowchart showing a flow of impurity discharge processing in the embodiment of the present invention. The impurity discharge process is started in response to the stop of power generation of the fuel cell (step S110). The reason for starting the processing after stopping the power generation of the fuel cell is to prevent the generation of the impurities from affecting the power generation of the fuel cell 100. Note that the supply of air and hydrogen gas to the fuel cell 100 is stopped along with the stoppage of power generation of the fuel cell.

  In step S120, the controller 600 starts measuring pressure by the two pressure gauges 610 and 620 (FIG. 1). The pressure gauge 610 and the pressure gauge 620 measure the pressure in the reaction air flow path 430 and the pressure in the environment control air flow path 432, respectively.

  In step S130, the controller 600 closes the shutoff valve 436. As a result, the air flow in the fuel cell external pipe 434 is cut off, so that the air supplied to the environment control air flow path 432 always flows to the reaction air flow path 430 via the porous portion P. become.

  In step S <b> 140, the controller 600 resumes the supply of air to the environment control air flow path 432. As a result, an air flow is formed from the environment control air flow path 432 to the reaction air flow path 430 through the porous portion P. This flow is a flow opposite to the flow of fluid during power generation by the fuel cell 100, that is, a reverse flow. The supply of air is controlled so that the air flow rate approaches a predetermined target value.

  FIG. 6 is an explanatory diagram showing a state in which impurities accumulated in the porous portion P are discharged in the embodiment of the present invention. As can be seen from FIGS. 4 and 6, the discharge of impurities is realized by the backflow formed in the porous portion P in this way. At this time, the controller 600 controls the air supply amount so that the pressure of the environment control air flow path 432 does not become excessive and the fuel cell 100 is damaged. Specifically, the air supply amount is controlled so that the pressure inside the environmental control air flow path 432 does not exceed a predetermined threshold (threshold for preventing damage).

  In this way, the air supply is controlled so that the air flow rate approaches the predetermined target value in a range where the pressure inside the environment control air flow path 432 does not exceed the threshold for preventing damage. The damage prevention threshold corresponds to the “third threshold” in the claims.

  The impurities discharged from the porous portion P are discharged from the cell 110 together with air through the reaction air lead-out path 430out. In this discharge process, when the air flow rate is sufficiently close to a predetermined target value, the difference between the pressure in the reaction air flow path 430 and the pressure in the environmental control air flow path 432 is a predetermined threshold value (stop determination). (Step S150).

  In this embodiment, the predetermined threshold value is determined to be a value that can determine that the blockage of the porous portion P has been sufficiently eliminated by the discharge of impurities. The stop determination threshold corresponds to the “second threshold” in the claims.

  In step S160, the controller 600 stops the fuel cell system 10. As a result, the fuel cell system 10 is stopped in a state where the impurities are discharged from the porous portion P, so that the impurities can be prevented from sticking to the porous portion P while the fuel cell system 10 is stopped. .

  Thus, in this embodiment, in the fuel cell 100 that drains the reaction air flow path 430 using the porous portion P, impurities can be discharged from the porous portion P. Blockage can be reduced.

  When the porous portion P is not clogged, the pressure difference does not reach the stop determination threshold value, the air flow rate approaches a predetermined target value, and the fuel cell system 10 is stopped. .

  Further, for example, even if the air flow rate approaches a predetermined target value, the fuel cell system 10 is immediately stopped if the pressure difference does not reach a threshold value (startup determination threshold value) larger than the stop determination threshold value. May be. In this way, if the porous portion is not clogged to some extent, the pressurization of the environmental control flow path is stopped. Therefore, the number of operations involving pressurization is reduced and the fuel cell is damaged by pressurization ( In particular, fatigue failure) can be suppressed. Furthermore, the energy required for operation can be reduced.

  In this case, the activation determination threshold corresponds to the “first threshold” in the claims, and the pressure difference reaches the activation determination threshold and pressurization is continued. Corresponds to “activation of a specific operation mode”.

C. Variations:
As mentioned above, although several embodiment of this invention was described, this invention is not limited to such embodiment at all, and implementation in various aspects is possible within the range which does not deviate from the summary. It is. For example, the following modifications are possible.

C-1. In the above embodiment, the environmental control flow path is disposed in the downstream portion of the reaction flow path and the refrigerant flow path is disposed in the downstream portion of the reaction flow path. You may comprise so that the flow path for environmental control may be arrange | positioned.

C-2. In the above embodiment, the clogging is eliminated by closing the shutoff valve installed upstream of the reaction channel and flowing the reaction gas from the environmental control channel to the reaction channel in the porous part. The clogging can be easily reduced by simply increasing the supply amount of the reaction gas without providing a shut-off valve. This is because the impurities staying in the reaction gas channel can be discharged to the outside, so that the intrusion of impurities into the porous portion can be suppressed. However, the above embodiment has an advantage that a more remarkable effect can be obtained.

  Further, the fuel cell is configured to include a valve for controlling the flow rate on the downstream side of one of the reaction flow path and the environment control flow path, and the reaction gas supply unit and the valve are controlled to react. The reaction gas may be caused to flow from the flow path on the side where the valve is provided to the other flow path of the main flow path and the environmental control flow path via the porous portion.

C-3. In the above embodiment, the reaction channel is connected in series downstream of the environmental control channel, but humidified air is supplied independently without connecting the reaction channel and the environmental control channel. It may be configured as described above.

  Specifically, for example, a humidifier (not shown) may supply the humidified air to the reaction flow path and supply unhumidified air to the environmental control flow path. As described above, the configuration in which air is supplied independently without connecting the reaction flow path and the environment control flow path has an advantage that fine control can be realized. This is because the humidity and flow rate of air supplied to the reaction channel and the environment control channel can be controlled independently. In the configuration in which air is supplied independently, the blockage is eliminated not only by flowing the reaction gas from the environment control channel to the reaction channel but also by flowing the reaction gas from the reaction channel to the environment control channel. There is also an advantage of being able to.

  On the other hand, the structure of the said Example has the advantage that the humidifier can be deleted from an air supply system as mentioned above, and the burden of a cooling system can be reduced.

C-4. In the above embodiment, the separator has a groove to form a reaction channel and an environment control channel. For example, a groove is provided on the electrode side to provide a reaction channel and an environment control channel. You may comprise so that it may form. In the present invention, the method of forming the groove in the separator is not limited to the electrode, and the reaction flow path is formed at a position in contact with the porous portion and the electrode, and the environment control flow is in a position in contact with the porous portion and not in contact with the electrode. It suffices if the fuel cell is configured so that the path is formed.

C-5. In the above embodiment, the fuel cell is configured to have the reaction channel and the environmental control channel on the oxygen electrode side. However, the fuel cell may be configured to have it on the hydrogen electrode side. . However, since excessive water is likely to be generated in the oxygen electrode, the present invention can achieve a remarkable effect in a configuration in which the reaction channel and the environmental control channel are provided on the oxygen electrode side.

C-6. In the above embodiment, the porous portion is cleaned in a specific operation mode of the fuel cell system. However, the porous portion is supplied to the reaction channel as in the fuel cell system 10a disclosed in the first modification, for example. The fuel cell may be equipped with a filter 439 for filtering the reaction gas, or may be combined. In this case, since impurities flowing into the reaction channel can be reduced, the amount of impurities entering the porous portion from the reaction channel can be reduced, and the blockage can be reduced.

  Here, the reason why the filter 439 is provided on the downstream side of the environment control flow path 432 is to filter impurities such as carbon powder, metal powder, and fiber waste generated inside the separator. You may make it equip in the upstream of the flow path 432 for use. Thus, the filter 439 should just be equipped in the position which can filter the reaction gas supplied to the flow path for reaction.

  Note that the filter may be filtered using a filter 431 that performs ion exchange as in the fuel cell system 10b disclosed in the second modification, for example. This is because impurities present as ions in the reaction gas can also be filtered. Further, there is an advantage that ions as impurities generated inside the fuel cell can be reduced.

  The ion exchange treatment preferably includes a cation exchange treatment. Since cation impurities cause a decrease in cation conductivity in the cation exchange membrane, this can also reduce fuel cell performance degradation due to the deposition of cation impurities on the cation exchange membrane. This is because there are advantages.

  Further, for example, a material configured to supply a fluid that dissolves or neutralizes impurities accumulated in the porous portion may be used. In general, the fuel cell of the present invention may be configured to include a clogging reduction portion that reduces clogging of the porous portion due to impurities entering the porous portion from the reaction channel.

C-7. In the above embodiment, the MEA uses a cation exchange membrane (proton exchange membrane) as an ion exchange membrane, but the present invention is widely applicable to fuel cells using an ion exchange membrane and has a remarkable effect. Play. Examples of the ion exchange membrane include a hydrocarbon ion exchange membrane and a fluorine ion exchange membrane. The present invention is not limited to fuel cells that use ion exchange membranes, and can be widely applied to fuel ionization that uses other electrolytes.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows schematic structure of the fuel cell system in the Example of this invention. FIG. 3 is an exploded perspective view showing a configuration of a cell of the fuel cell 100. Explanatory drawing which shows a mode that a reactive gas and a cooling fluid flow through the flow path formed in the separator. Explanatory drawing which shows a mode that produced | generated water moves via the porous part P. FIG. Explanatory drawing which shows a mode that the impurity accumulate | stored in the porous part P is discharged | emitted in a present Example. Explanatory drawing which shows a mode that the impurity accumulate | stored in the porous part P in the Example of this invention is discharged | emitted. Explanatory drawing which shows schematic structure of the fuel cell system in the 1st modification of this invention. Explanatory drawing which shows schematic structure of the fuel cell system in the 2nd modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 100 ... Fuel cell 110 ... Cell 120 ... MEA
122 ... Electrolyte membrane 124 ... Oxygen electrode 126 ... Hydrogen electrode 130 ... Hydrogen electrode side separator 140 ... Oxygen electrode side separator 302 ... Hydrogen tank 304 ... Pressure reducing valve 306 ... Flow control valve 310 ... Hydrogen gas supply pipe 330 ... Hydrogen gas flow path 330in ... Hydrogen gas introduction path 330out ... Hydrogen gas lead-out path 390 ... Hydrogen gas discharge pipe 392 ... Shut-off valve 402 ... Air blower 410 ... Air supply pipe 430 ... Reaction air flow path 430in ... Reaction air introduction path 430out ... Reaction air lead-out Path 432 ... Environment control air flow path 432 in ... Environment control air introduction path 432 out ... Environment control air lead-out path 434 ... Fuel cell external pipe 436 ... Shut-off valve 490 ... Air discharge pipe 502 ... Circulation pump 504 ... Heat exchanger 510 ... Coolant supply pipe 530 ... Coolant flow channel 530in ... Coolant guide Road 530Out ... coolant outlet passage 600 ... controller 610 ... pressure gauge

Claims (5)

A fuel cell,
Electrolyte,
First and second electrodes having a catalyst layer, wherein the catalyst layer is joined to the electrolyte;
A first separator having at least a portion of a porous portion formed of a porous material and provided in contact with the first electrode;
With
In the fuel cell, at least a part of the reaction channel is formed at a position in contact with the porous portion and the first electrode, and at a position in contact with the porous portion and not in contact with the first electrode. It is configured to form a flow path for environmental control,
The fuel cell further includes a clogging reduction unit that reduces clogging of the porous part due to impurities entering the porous part from at least one of the reaction channel and the environment control channel,
The clogging reduction unit includes a filter that filters the reaction gas supplied to at least one of the reaction channel and the environment control channel,
The fuel cell according to claim 1, wherein the filter performs a filtration process including a filtration by an ion exchange process. The fuel cell according to claim 1, wherein
The ion exchange treatment includes a cation exchange treatment. The fuel cell according to claim 1, wherein
An oxidation gas is supplied to the reaction flow path. A fuel cell according to any one of claims 1 to 3,
The fuel cell, wherein the first separator is formed with a refrigerant flow path for flowing a refrigerant for cooling the fuel cell. A fuel cell according to any one of claims 1 to 4,
The fuel cell is configured so that the environmental control flow path is connected in series upstream of the reaction flow path.

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