JP2008198496A - Polymer electrolyte fuel cell and its characteristic recovery method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer electrolyte fuel cell and its characteristic recovery method capable of recovering characteristics deteriorated in order to increase durability. <P>SOLUTION: The polymer electrolyte fuel cell has a fuel cell stack 1; fuel gas piping G; air piping A; and cooling water piping P including a cooling water pump 11. The cooling water piping P has the cooling water pump 11; a cooling water tank 12; and a pressure control valve 13 on the inlet side of the fuel cell stack 1. The pressure control valve 13 is controlled by a cooling water pressure control means 14. The cooling water pressure control means 14 controls to decrease cooling water pressure of the cooling water piping P based on the judgement of whether cumulative power generation time exceeds or not a previously set time by a cumulative power generation time monitoring means 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polymer electrolyte fuel cell capable of recovering characteristics even when it deteriorates in order to improve durability, and a method for recovering the characteristics thereof.

  Fuel cells are classified into various types depending on the difference in electrolytes, etc., but solid polymer fuel cells using a solid polymer electrolyte membrane as the electrolyte are generally used because of their low-temperature operability and high output density. This fuel cell is suitable for use as a power source for small-sized cogeneration systems and electric vehicles with a view to home use, and is a fuel cell whose market scale will expand rapidly in the future.

  This solid polymer fuel cell is a reforming device that produces hydrogen-containing gas from hydrocarbon-based fuels typified by city gas, LPG, and the like, taking a small cogeneration system for stationary household use as an example. The fuel cell stack that generates electromotive force by supplying the hydrogen-containing gas and air in the atmosphere produced by the gas generator to the fuel electrode and the oxidant electrode, and the electricity that supplies the electric energy generated by the fuel cell stack to the external load It is composed of a control device and a heat utilization system that recovers heat generated by power generation.

  In this way, fuel operation is premised on the operation of the fuel cell power generation system. Therefore, the higher the power generation efficiency defined by the amount of power generated relative to the amount of fuel input, the lower the amount of fuel used and the higher the user merit. Become. Therefore, the power generation efficiency is an index indicating the performance of the fuel cell power generation system.

  Here, in the fuel cell power generation system, the fuel cell stack is actually responsible for the power generation function, and includes a plurality of stacked fuel cell stacks starting with a single cell. The decrease in power generation efficiency is mainly caused by the voltage of the fuel cell stack decreasing with time due to various factors associated with continuous operation. That is, the most important point in providing a fuel cell power generation system with high power generation efficiency is to suppress or recover the voltage drop of the fuel cell stack over time.

  In order to prevent the voltage drop of the fuel cell stack over time and maintain power generation with good characteristics, the fuel cell stack is continuously operated by adding a certain amount of humidification to the solid polymer electrolyte membrane of the fuel cell stack based on the principle of power generation. It is necessary to let As this humidification method, an external humidification method that humidifies from the outside of the stack and an internal humidification method are known, and among these, the internal humidification method is attracting attention as an effective means for uniformly humidifying the film. (See Patent Document 1).

  In this internal humidification system, a flow path of fuel gas or air is formed on the electrode side, and a flow path of water that allows cooling water to flow to the adjacent fuel cell side on the opposite side. For example, a carbon plate made of a formed porous material is used as a material. That is, humidification is performed using the water capillary phenomenon, which is a characteristic of the porous body.

In such a method, by setting a pressure higher than the cooling water side on the electrode side and applying a differential pressure by controlling this pressure below the pressure at which the capillary phenomenon can be applied, excess water generated even during power generation This is an efficient method for water management of polymer electrolyte fuel cells.
Japanese National Patent Publication No. 11-508726

  However, even when the method shown in Patent Document 1 is used, if power generation is continued for a long time under a predetermined operating condition, the function over time such as the moisture retention ability of the pores in the porous body may deteriorate. As a result, the uniform performance of water management between multiple stacked cells and in the cell plane is impaired against the sucking performance of the generated water from the electrode and the moisture retention to the electrode and the solid polymer membrane. Inhibition, so-called flooding or lack of moisture retention occurs.

  The deterioration phenomenon due to the uniformity of water management in the cell plane is accompanied by not only the normal deterioration phenomenon over time but also the characteristic deviation in the cell plane, and promotes the local generation of generated water. For this reason, an excessive amount of water is partially generated and exceeds the water treatment range of the porous body, resulting in flooding. The reaction is hindered by flooding, and the further in-cell characteristics are biased. As a result, the characteristics of the fuel cell characteristics themselves are lowered, and the durability is accelerated.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a fuel cell power generation system capable of recovering characteristics even when deteriorated and a recovery operation method thereof in order to improve durability. There is to do.

  In order to solve the above problems, the present invention provides a single cell having a fuel electrode and an oxidant electrode arranged with an electrolyte interposed therebetween, and a reaction for supplying a reactive gas to the single cell formed of a conductive porous body. A fuel cell stack including a gas circulation part and a cooling water circulation part for circulating the cooling water of the single cell formed of a conductive porous body; and cooling water in the cooling flow path of the fuel cell stack. A pressure difference adjusting means for adjusting a pressure difference between a reaction gas pressure in the reaction gas circulation part and a cooling water pressure in the cooling water circulation part in a polymer electrolyte fuel cell provided with a circulating cooling water system It is provided with. In addition, although the shape as a reactive gas distribution | circulation part and a cooling water distribution | circulation part is not prescribed | regulated, it is set as the shape provided with flow paths, such as a groove | channel, here as needed.

  In the fuel cell stack, flooding occurs due to deterioration over time after a predetermined cumulative power generation time has elapsed, and when the cumulative power generation time exceeds a predetermined time, a water removal function is required depending on the setting. According to the invention, the pressure difference between the reaction gas pressure in the reaction gas passage and the cooling water pressure in the cooling water passage is adjusted while maintaining the heat removal by the cooling water. Specifically, while controlling the flow rate of the cooling water to a constant level, the pressure of the cooling water is controlled to decrease, and the pressure difference between the oxidizer electrode and the fuel electrode and the porous separator is increased, so that the flooding phenomenon occurs. If so, it can be resolved. In addition, insufficient water retention inside the porous separator that causes insufficient moisture retention and voids generated by continuous operation cause water to penetrate into the separator due to an increase in the pressure difference, and this operation increases the pressure difference between the cooling water and the electrode. Thus, the water removal function can be enhanced.

  According to the present invention as described above, the characteristics of the fuel cell stack can be improved by adjusting the pressure difference between the reaction gas pressure in the reaction gas channel and the cooling water pressure in the cooling water channel to reduce the cooling water pressure. It is possible to provide a polymer electrolyte fuel cell that can be recovered and thereby extend the life of the fuel cell stack, and a method for recovering the characteristics thereof.

  Hereinafter, typical embodiments according to the present invention will be specifically described with reference to FIGS.

(1) First Embodiment FIG. 1 is a diagram showing a configuration of a polymer electrolyte fuel cell according to a first embodiment of the present invention, in which a broken line is a gas pipe, a solid line is cooling water, and an alternate long and short dash line Denotes voltage measurement circuits (the same applies to FIGS. 6 and 10).

(1-1) Configuration As shown in FIG. 1, the solid polymer fuel cell according to the present embodiment includes a fuel cell stack 1, a fuel gas pipe G, an air pipe A, and a cooling water pipe including a cooling water pump 11. P. In FIG. 1, the fuel cell stack 1 is expressed as a single cell for convenience of explanation, but actually, a plurality of the fuel cell stacks 1 are formed in series.

  The configuration of the fuel cell stack 1 of the present embodiment is the same as the conventional one, and is configured such that the electrolyte 4 is sandwiched between the fuel electrode 2 and the oxidant electrode 3. Further, separators 10 are provided at both electrodes of the fuel cell stack 1 so as to sandwich the fuel electrode 2, the oxidant electrode 3, and the electrolyte 4. As described above, in FIG. 1, the fuel cell stack is represented by a single cell. However, in the case where a plurality of fuel cell stacks are actually stacked, the separators are stacked one by one between the fuel electrode and the oxidant electrode. .

  A hydrogen rich gas is supplied to the fuel electrode 2 as a fuel gas from a reformer or the like through a fuel gas pipe G, and air is supplied to the oxidizer electrode 3 through an air pipe A, thereby generating electric power. In addition, the separator 10 includes a cooling water flow path that is circulated by the cooling water pump 11 for the purpose of cooling heat generated by power generation, absorbing generated water, and humidifying the solid polymer electrolyte membrane 4.

  The cooling water pipe P includes a cooling water pump 11, a cooling water tank 12, and a pressure control valve 13 on the inlet side of the fuel cell stack 1. The cooling water pipe P is branched into two on the downstream side of the pressure control valve 13 and is connected to the flow paths of the two separators 10 provided on both pole sides of the fuel cell stack 1. The two branched pipes merge on the downstream side of the separator 10, pass through the cooling water pump 11, and are piped to the cooling water tank 12.

  The pressure control valve 13 is controlled by the cooling water pressure control means 14. In the control by the cooling water pressure control means 14, the cumulative power generation time monitoring means 15 determines whether or not the cumulative power generation time exceeds a preset time, and based on this, the cooling water pressure of the cooling water pipe P is set. Control to reduce is performed. In addition, the flow rate is controlled by changing the number of rotations of the cooling water pump 11 with respect to the flow rate variation caused by the cooling water pressure drop.

(1-2) Operational Effects Next, normal operations relating to the improvement of flooding according to the present embodiment configured as described above will be described.

In general, in the power generation of a fuel cell, protons (H ⁺ ) obtained from the fuel electrode move to the oxidant electrode, and the oxidant electrode continues the power generation while water is generated by combining the proton and oxygen. . Accordingly, as a moisture management for the fuel electrode 2, the oxidant electrode 3, and the electrolyte membrane 4, the water generated in the oxidant electrode 3 becomes capillary action of the porous separator 10 circulated by the cooling water pump. While the excess water is absorbed into the cooling water, the fuel electrode 2 causes a slight reverse movement of water due to permeation from the oxidizer electrode 3, but it is insufficient for supplying moisture to the fuel electrode 2 side. Contrary to the function of the porous separator 10 to the oxidant electrode 3, moisture is supplied by capillary action. However, even if water management is performed on such an electrode, in the long-time power generation, as the function of the porous separator 10 decreases, the water suction performance decreases as it is, so-called flooding phenomenon or Insufficient moisture retention occurs.

  Therefore, in the present embodiment, the cooling water pump 11 is operated to circulate the cooling water in order to ensure the flow rate in the cooling water system through which the porous separator passes. Further, by adjusting the pressure at the inlet portion of the fuel cell stack 1 by the pressure control valve 13 disposed at the inlet of the fuel cell stack 1, an electrode composed of the fuel electrode 2 and the oxidant electrode 3, the separator 10, Adjust the pressure difference.

  More specifically, as shown in the flowchart of FIG. 2, the cumulative power generation time monitoring means 15 monitors whether or not the cumulative power generation time of the fuel cell stack 1 exceeds the set value (S201), and exceeds it. (YES), the cooling water pressure control means 14 controls the pressure control valve 13 to reduce the pressure of the cooling water (S202). Thereby, the pressure difference between the electrode constituted by the fuel electrode 2 and the oxidant electrode 3 and the separator 10 is adjusted.

  If the gas supply system of the fuel cell stack 1 is at normal pressure, the cooling water system including the porous separator 10 also has a feature that the cooling water system has a negative pressure rather than atmospheric pressure.

  Water management is performed by the pressure difference between the oxidant electrode 3 and the fuel electrode 2 and the porous separator 10 that have been operated so far, but at least one of the porous separator 10 or the oxidant electrode 3 and the fuel electrode 2 is Then, flooding occurs due to deterioration over time after a predetermined cumulative power generation time has elapsed. Therefore, when the accumulated power generation time exceeds a predetermined time, a water removal function is required depending on the setting. Therefore, in such a case, the pressure control valve 13 reduces the inlet pressure of the fuel cell stack 1 while maintaining the heat removal by the cooling water.

  By reducing the pressure and increasing the pressure difference between the oxidant electrode 3 and the fuel electrode 2 and the porous separator 10, if a flooding phenomenon occurs, it can be eliminated, and the porous separator 10. Water penetrates to the inside of the separator 10 due to an increase in pressure difference in the voids caused by insufficient internal hydrophilicity or continuous operation. By this operation, the water removal function can be enhanced by increasing the pressure difference between the cooling water and the electrode. However, not only the setting based on the accumulated power generation time, but also the variation control of the pressure difference is performed as shown in FIG. 3, for example, the pressure difference is changed by the elapsed time at each start-up or the fuel cell stack 1 battery voltage drop. The same effect can be obtained by a method of gradually changing the pressure over time.

  According to the present embodiment as described above, the life of the fuel cell stack 1 can be extended. In this regard, FIG. 4 shows a change in the voltage of the fuel cell stack 1 when the pressure control valve 13 is controlled by the cooling water pressure control means 14 and the cooling water pressure at the inlet of the fuel cell stack 1 is reduced. According to this, as the cooling water pressure decreases, a voltage increase is seen, and it can be seen that the characteristics of the fuel cell stack 1 are recovered.

  FIG. 5 shows the voltage distribution of the fuel cell stack 1 in which a plurality of cells are stacked when the coolant pressure at the inlet of the fuel cell stack 1 is reduced by the pressure control valve 13 and further increased from a predetermined differential pressure. It shows the relative value of standard deviation and cell average voltage. This shows that the standard deviation is improved by 10% or more. This indicates that the voltage of the fuel cell having particularly deteriorated characteristics is increasing in the fuel cell stack 1, and it can be seen that the life of the fuel cell stack 1 can be extended by this embodiment.

(2) Second Embodiment (2-1) Configuration A polymer electrolyte fuel cell according to a second embodiment of the present invention will be described. The polymer electrolyte fuel cell of the present embodiment is characterized by performing an operation for confirming flooding or lack of moisture retention and detecting whether at least one of flooding or lack of moisture retention has occurred. Specifically, as shown in FIG. 6, a voltmeter 20 for a fuel cell stack is provided, and the voltmeter 20 is used to confirm whether a fuel cell stack deterioration state due to flooding has occurred. In addition, about the other structure and operating method in the polymer electrolyte fuel cell of this embodiment, it is the same as that of 1st Embodiment.

  This embodiment is characterized by detecting whether flooding has occurred by periodically performing a pressure fluctuation operation. Here, in the polymer electrolyte fuel cell, it is usually easy to detect the deterioration of the water management function by using, for example, a test apparatus for quality inspection at the manufacturing site. However, in practice, it is not practical to perform the confirmation operation with such a test apparatus. Therefore, in the present embodiment, as one of effective and simple methods for the detection, whether or not the fuel cell stack has deteriorated due to flooding is normally provided for operating the fuel cell stack. Measurement is performed by a voltmeter 20 for the battery stack.

  More specifically, as shown in FIG. 6, the polymer electrolyte fuel cell of the present embodiment has a current in addition to the cooling water pressure control means 14 and the accumulated power generation time monitoring means 15 shown in the first embodiment. Control means 16 and voltage determination means 17 are provided.

(2-2) Operational Effect Next, the operation of the present embodiment will be described with reference to the flowchart of FIG. In performing the operation, a predetermined period is provided during power generation, and the state is periodically changed to a state in which the deterioration state of the fuel cell is inspected (START). The accumulated power generation time monitoring means 15 monitors whether or not the accumulated power generation time of the fuel cell stack 1 exceeds the set value (S601), and if it exceeds (YES), the current control means for setting the inspection state. 16 starts control to make the current constant (S602), and maintains the stable state of the fuel cell stack 1 (S603). Then, the cooling water pressure control means 14 controls the pressure control valve 13 to reduce the pressure of the cooling water (S604). Thereby, it changes so that the pressure difference of the electrode which consists of the fuel electrode 2 and the oxidizing agent electrode 3 and the separator 10 may rise.

  Next, the voltage determination means 17 measures the voltage fluctuation (S605). If the voltage transition exceeds the voltage before the fluctuation (YES), it is determined that the deterioration has occurred, and the cooling water The pressure control means 14 changes the pressure difference again so as to return to the original value (S606). On the other hand, in step S605, if the voltage remains unchanged at the measured voltage, it is determined that no flooding has occurred (NO), and this determination is repeated periodically at a predetermined time.

  Subsequently, the voltage of the fuel cell stack 1 at this time is measured by the voltage determination means 17 (S607). If this voltage does not increase and does not increase, that is, if it does not return (YES), flooding has occurred. The cooling water pressure control means 14 controls the pressure control valve 13 to reduce the pressure of the cooling water (S608). At this time, as shown in FIG. 8, the voltage of the fuel cell stack 1 decreases over time.

  On the other hand, when the voltage rises without decreasing, that is, when the voltage returns to the original value (NO), the process is terminated (END).

  Then, the voltage determination means 17 measures the voltage of the fuel cell stack 1 again (S609). If the voltage rises (YES), it is determined that the deterioration has occurred, and the cooling water pressure control means 14 Thus, the pressure control valve 13 is controlled to reduce the pressure of the cooling water (S610), and the process is terminated (END). On the other hand, when the voltage decreases (NO), the process returns to S606 and the subsequent processing is periodically repeated at a predetermined time.

  If the predetermined effect of voltage increase due to differential pressure fluctuation is obtained by the above diagnosis, the set value is changed so that the differential pressure is obtained, and the battery current constant control is canceled to return to the normal state, or the differential pressure is If there is no effect of voltage increase due to the increase, the differential pressure is restored to the normal state.

  In addition, as shown in FIG. 9, there is a characteristic that the amplitude of the voltage is large and the period is fast even if the pressure is not changed during the occurrence of flooding. Can be judged.

  According to the present embodiment as described above, whether or not the fuel cell stack has deteriorated due to at least one of flooding or insufficient moisture retention is measured by a voltmeter and determined by a transition of a voltage higher than the measured voltage. On the other hand, if the voltage does not indicate a voltage higher than the measured voltage, it can be determined that the separator function has not deteriorated. Thereby, it becomes easy to recognize a decrease in separator function of the fuel cell.

(3) Third Embodiment A polymer electrolyte fuel cell according to a third embodiment of the present invention will be described. The polymer electrolyte fuel cell of the present embodiment detects flooding or insufficient moisture retention due to separator function deterioration based on the function deterioration information shown in the second embodiment, and performs the operation shown in the first embodiment. That's what it meant.

  That is, whether or not at least one of flooding due to deterioration of the separator function or insufficient moisture retention occurs is measured by the voltmeter 20, and when the voltage determination means 17 shows a transition of a voltage higher than the measured voltage. Determines that such deterioration has occurred. Then, the cooling water pressure control means 14 controls the pressure control valve 13 to reduce the pressure of the cooling water. Thereby, the pressure difference between the electrode constituted by the fuel electrode 2 and the oxidant electrode 3 and the separator 10 is adjusted.

  On the other hand, if the voltage determination means 17 does not determine that the voltage is higher than the measured voltage, it is determined that the separator function has not deteriorated, and the pump rotational speed increases or the pressure increases the auxiliary power. Since it is not necessary to change the control valve, an operation for returning to the original state is performed.

  As a result, it is possible to know a state in which the separator function of the fuel cell has been lowered, and to minimize the deterioration state.

(4) Other Embodiments The present invention is not limited to the embodiment as described above, and can be implemented, for example, in the following manner. For example, in the first embodiment, the pressure of the cooling water is realized by controlling with the pressure control valve 13, but it is characterized by controlling the pressure difference, but such pressure control is performed. In order to do this, a control valve is not necessarily required. For example, it is also possible to increase the cooling water flow rate by increasing the output of the cooling water pump 11. In addition, as shown in FIG. 10, the pressure difference between the electrode and the cooling water can be increased by providing the pressure control valves 21a and 21b in at least one of the oxidant or the fuel on the electrode side while keeping the pressure of the cooling water system as it is. Is possible.

The figure which shows the whole structure of the 1st Embodiment of this invention. The flowchart which shows the effect | action of the 1st Embodiment of this invention. The graph which shows the characteristic recovery state of the fuel cell stack of the 1st Embodiment of this invention. The graph which shows the characteristic recovery state of the fuel cell stack of other embodiment of this invention. The graph which shows the effect of the 1st Embodiment of this invention. The figure which shows the whole structure of the 2nd Embodiment of this invention. The flowchart which shows the effect | action of the 2nd Embodiment of this invention. The graph which shows the characteristic recovery state of the fuel cell stack of the 2nd Embodiment of this invention. The graph which shows the characteristic recovery state of the fuel cell stack of the 2nd Embodiment of this invention. The figure which shows the whole structure of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell stack 2 ... Fuel electrode 3 ... Oxidant electrode 4 ... Solid polymer electrolyte membrane 4 ... Electrolyte membrane 4 ... Electrolyte 10 ... Porous separator 11 ... Cooling water pump 12 ... Cooling water tanks 13, 21a, 21b ... Pressure Control valve 14 ... Cooling water pressure control means 15 ... Cumulative power generation time monitoring means 16 ... Current control means 17 ... Voltage determination means 20 ... Voltmeter A ... Air pipe G ... Fuel gas pipe P ... Cooling water pipe

Claims (10)

Conductivity in which a reaction gas distribution part for supplying a reaction gas and a cooling water distribution part for circulating cooling water are arranged on the back side of a single cell in which a fuel electrode and an oxidant electrode are arranged with an electrolyte in between. In a polymer electrolyte fuel cell comprising: a fuel cell stack formed by laminating via a porous separator; and a cooling water system that circulates and supplies cooling water to the cooling water circulation part of the fuel cell stack.
A solid polymer fuel cell comprising pressure difference adjusting means for adjusting a pressure difference between a reaction gas pressure in the reaction gas circulation part and a cooling water pressure in the cooling water circulation part.   2. The solid polymer type according to claim 1, wherein the pressure difference adjusting means adjusts the cooling water pressure by controlling at least one of a pressure adjusting valve or a pump provided in the cooling water system. Fuel cell.   The pressure difference adjusting means controls a pressure adjusting valve provided in a fuel gas circulation part or an oxidant circulation part that supplies fuel gas and air to the fuel electrode and the oxidant electrode, respectively, to control the fuel gas and the air. 2. The polymer electrolyte fuel cell according to claim 1, wherein the pressure is adjusted. A cumulative power generation time monitoring means for monitoring the cumulative power generation time of the fuel cell stack;
When the accumulated power generation time detected by the accumulated power generation time monitoring unit exceeds a predetermined time, the pressure difference adjustment unit is configured to reduce a reaction gas pressure of the reaction gas circulation unit and a cooling water pressure of the cooling water circulation unit. The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein a pressure difference is adjusted. A voltmeter for measuring the voltage of the fuel cell stack is provided,
Voltage determination means for determining a variation in voltage detected by the voltmeter;
The pressure difference adjusting means adjusts the pressure difference between the reaction gas pressure in the reaction gas flow path and the cooling water pressure in the cooling water circulation part when the voltage of the fuel cell stack decreases, and the fuel 5. The solid polymer according to claim 4, wherein when the voltage of the battery stack returns to the original value or increases, the process of canceling the adjustment of the pressure difference is repeated at a predetermined time interval. Fuel cell. A voltmeter for measuring the voltage of the fuel cell stack is provided,
Voltage determination means for determining a variation in voltage detected by the voltmeter;
The pressure difference adjusting means is configured such that when the voltage of the fuel cell stack decreases after the accumulated power generation time exceeds a predetermined time, the reaction gas pressure of the reaction gas circulation part and the cooling water pressure of the cooling water circulation part 6. The polymer electrolyte fuel cell according to claim 4, wherein a pressure difference between the solid polymer fuel cell and the fuel cell is adjusted. Current control means for controlling operation of the fuel cell stack at a constant current for a predetermined time;
When the voltage of the fuel cell stack decreases while the fuel cell stack is being controlled to operate at a constant current by the current control unit for a predetermined time, the pressure difference adjusting unit 7. The polymer electrolyte fuel cell according to claim 6, wherein a pressure difference between the reaction gas pressure of the cooling water and the cooling water pressure of the cooling water circulation part is adjusted.   The pressure difference adjusting means, when the voltage determination means determines that the fluctuation increase width of the voltage of the fuel cell stack exceeds a predetermined value, the reaction gas pressure of the reaction gas circulation section and the cooling water circulation section 8. The polymer electrolyte fuel cell according to claim 7, wherein a pressure difference from the cooling water pressure is adjusted. Power generation time monitoring means for monitoring the time from the start of power generation of the fuel cell stack in one activation of the apparatus,
When the time from the start of power generation detected by the power generation time monitoring unit exceeds a predetermined time, the pressure difference adjusting unit is configured to change a reaction gas pressure in the reaction gas circulation unit and a cooling water pressure in the cooling water circulation unit. The solid polymer fuel cell according to any one of claims 1 to 3, wherein the pressure difference between the two is adjusted. Conductive porous material in which the reaction gas circulation part for supplying the reaction gas and the cooling water circulation part for circulating the cooling water are arranged on the back surface of the single cell in which the fuel electrode and the oxidant electrode are arranged with the electrolyte in between. A fuel cell stack formed by stacking through a porous separator, and a cooling water system for circulating and supplying cooling water to the cooling water circulation part of the fuel cell stack, and a method for recovering characteristics of a polymer electrolyte fuel cell In
A method for recovering characteristics of a polymer electrolyte fuel cell, comprising performing a pressure difference adjustment process for adjusting a pressure difference between a reaction gas pressure in the reaction gas channel and a cooling water pressure in the cooling water channel.

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