HYDROGEN SUPPLY METHOD FOR A FUEL CELL SYSTEM

Abstract

A hydrogen supply method for a fuel cell system to supply hydrogen according to a state of the fuel cell system when the fuel cell system is started, wherein the hydrogen supply method comprises the following steps: (a) measuring a stop time that elapses until the fuel cell system is restarted after the fuel cell system has been stopped; (b) determining whether a reaction time required to complete a reaction of residual hydrogen and residual oxygen located in a fuel cell stack (10) since the fuel cell system was stopped is not longer than the stop time;and (c) closing a purge valve capable of venting gases contained in an anode (12) from the anode (12) and simultaneously supplying hydrogen to the anode (12) such that an internal pressure of the anode (12) becomes a predetermined first setpoint pressure when, in step (b), it is determined that the stop time is shorter than the reaction time, the hydrogen supply method further comprising a step: prior to step (b), a step (d) comprising: (d) measuring the internal pressure of the anode (12); (e) determining whether the internal pressure of the anode (12) measured in step (d) is less than a predetermined abnormal pressure; (f) opening the purge valve and simultaneously supplying hydrogen to the anode (12) such that the internal pressure of the anode (12) becomes a predetermined maximum allowable pressure when, in step (e), it is determined that the internal pressure is not less than the predetermined abnormal pressure;(g) Determine whether a crossing time, for which residual gases contained in the fuel cell stack (10) cross through a polymer electrolyte membrane (11) and the anode (12) and the cathode (13) are in pressure equilibrium after the fuel cell system has been stopped, is not less than the stop time duration, if in step (e) it is found that the internal pressure of the anode (12) is less than the specified abnormal pressure; (h) Estimate the partial pressures of the remaining gases, excluding hydrogen, contained in the anode (12) with reference to the internal pressure of the anode (12) measured in (d), if in step (g) it is found that the stop time duration is less than the crossing time; and (i) Close the vent valve and simultaneously supply to the anode (12) an amount of hydrogen corresponding to the partial pressures of the remaining gases estimated in step (h).

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is based upon and claims the benefit of priority from Korean Patent Application No. 10-2017-0084349, filed on July 3, 2017, in the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present invention relates to a hydrogen supply method for a fuel cell system, in which hydrogen is supplied to a fuel cell system. BACKGROUND

[0003] Fuel cells are the main power source of a fuel cell system and generate electricity through an oxidation / reduction reaction of hydrogen and oxygen.

[0004] High-purity hydrogen is supplied from a hydrogen storage tank to an anode of a fuel cell stack (hereinafter referred to as a "stack"), and air in the atmosphere, supplied by an air compressor or other utilities, is introduced into a cathode of the stack.

[0005] At the anode, an oxidation reaction of hydrogen occurs to generate hydrogen ions (e.g., protons) and electrons. The hydrogen ions and electrons thus generated are transferred to the cathode via a polymer electrolyte membrane and a separator. Furthermore, a reduction reaction occurs at the cathode, involving the hydrogen ions and electrons that have moved away from the anode and the oxygen in the air supplied by an air supply device, thus generating water. At the same time, electrical energy is generated by the flow of electrons.

[0006] However, the hydrogen flowing through the anode is returned to the anode via a hydrogen return line, and nitrogen and other gases contained in the air flowing through the cathode cross the polymer electrolyte membrane and are introduced into the anode through the polymer electrolyte membrane. Accordingly, with the increasing operating time of the fuel cell system, the hydrogen concentration in the anode gradually decreases.

[0007] When the hydrogen concentration in the anode is 70% or more, maintaining the performance of the fuel cell system at peak levels is no problem. However, if the hydrogen concentration in the anode drops below 70%, the performance of the fuel cell system deteriorates. To solve this problem, existing fuel cell systems perform hydrogen purging, which involves passing hydrogen and other gases outside the fuel cell system via the hydrogen return line to adjust the hydrogen concentration in the anode.

[0008] Furthermore, when the fuel cell system is stopped, the hydrogen concentration in the anode changes according to the time elapsed since the fuel cell system was stopped due to the reaction of residual hydrogen and residual oxygen, the cross-pollination of nitrogen and other gases, and the introduction of outside air through a valve or other elements. However, when the fuel cell system is started up, existing fuel cell systems collectively perform hydrogen purging without considering the change in the hydrogen concentration in the anode corresponding to the stop period.Accordingly, in the existing fuel cell system, when excessive hydrogen purging is performed during the startup of the fuel cell system, a supply pressure of hydrogen increases and an amount of hydrogen discharged to the outside increases, which makes it difficult to meet regulations on the hydrogen concentration of exhaust gases. OVERVIEW

[0009] The present invention provides an improved hydrogen supply method for a fuel cell system that can reduce hydrogen purging performed at start-up of a fuel cell system.

[0010] The present invention also provides an improved hydrogen supply method for a fuel cell system that can reduce an amount of hydrogen released to the outside of the fuel cell system when the fuel cell system is started.

[0011] The present invention also provides an improved hydrogen supply method for a fuel cell system that can reduce the pressure of the supplied hydrogen when starting the fuel cell system.

[0012] The present invention also provides an improved hydrogen supply method for a fuel cell system that can reduce the hydrogen concentration of exhaust gases released during start-up of the fuel cell system.

[0013] The present invention also discloses an apparatus and method for controlling autonomous driving of a vehicle, with which an alarm can be issued when a predicted collision of a driver, which is calculated while driving a vehicle with reference to a permissible collision of the driver, exceeds the permissible collision of the driver, and a vehicle system.

[0014] The objects of the present invention are not limited to those mentioned above, and the other technical objects not mentioned will become apparent to those skilled in the art from the following description.

[0015] According to one aspect of the present disclosure, a hydrogen supply method for a fuel cell system is provided to supply hydrogen according to a state of the fuel cell system at startup of the fuel cell system.The hydrogen supply method includes the following steps: (a) measuring a stop time period that elapses until the fuel cell system is restarted after the fuel cell system is stopped, (b) determining whether a reaction time period required to complete a reaction of residual hydrogen and residual oxygen located in a fuel cell stack when the fuel system is stopped is not longer than the stop time period, and (c) closing a purge valve capable of discharging the gases accommodated in an anode from the anode and simultaneously supplying hydrogen to the anode so that an internal pressure of the anode becomes a predetermined first target pressure, if it is determined in step (b) that the stop time period is shorter than the reaction time period.

[0016] The predetermined first target pressure can be adjusted so that a concentration of hydrogen in the anode becomes a predetermined first target concentration.

[0017] The hydrogen supply method may further comprise a step (d) before step (b) which measures the internal pressure of the anode.

[0018] The hydrogen supply method may further comprise the steps of: (e) determining whether the internal pressure of the anode measured in step (d) is less than a predetermined abnormal pressure, and a step of (f) opening the purge valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes a predetermined maximum allowable value if it is determined in step (e) that the internal pressure is not less than the predetermined abnormal pressure.

[0019] The hydrogen supply method may further comprise: a step (g) in the case where it is determined in step (e) that the internal pressure of the anode is less than the predetermined abnormal pressure, wherein for the residual gases present in the fuel cell stack and which pass through a polymer electrolyte membrane and the anode and the cathode in pressure equilibrium after the fuel cell system is stopped, it is determined whether a crossing time is not less than the stop time period; a step (h) of estimating the partial pressures of the remaining gases, excluding hydrogen, of the gases accommodated in the anode with reference to the internal pressure of the anode measured in step (d) in the case where it is determined in step (g) that the stop time period is less than the crossing time; and (i) closing the purge valve and simultaneously supplying an amount of hydrogen corresponding to the partial pressures of the remaining gases;which are estimated in step (d).

[0020] Step (i) may comprise: (i1) setting a second target pressure of the anode with respect to a predetermined second target concentration of the hydrogen accommodated in the anode and the partial pressures of the remaining gases estimated in step (h), and (i2) closing the purge valve and simultaneously supplying the hydrogen to the anode so that the internal pressure of the anode becomes the second target pressure.

[0021] The hydrogen supply method may further comprise: a step (j) if it is determined in step (g) that the stop time is equal to or greater than the crossing time, determining whether a condensation time consumed for completely condensing steam located in the anode when the fuel cell system is stopped is equal to or greater than the stop time, a step (k) of estimating the partial pressures of the remaining gases, except for hydrogen, of the gases accommodated in the anode in the case where it is determined in step (j) that the stop time is less than the condensation time, and a step ( 1 ) with closing the purge valve and simultaneously supplying to the anode an amount of hydrogen corresponding to the partial pressures of the remaining gases estimated in step (k).

[0022] Step (k) may comprise estimating the partial pressures of the remaining gases with respect to the internal pressure of the anode measured in step (d).

[0023] The hydrogen supply method may further include step (m) between step (j) and step (k) of estimating an amount of vapor accommodated in the anode that has been condensed during the stop period, and step (k) may further include estimating partial pressures of the remaining gases with respect to the internal pressure of the anode measured in step (d) and the amount of condensed vapor estimated in step (d).

[0024] Step (m) may comprise estimating the amount of condensed vapor with respect to the internal pressure of the anode.

[0025] The step ( 1 ) may include: ( 11) Setting a third target pressure of the anode in relation to a predetermined third target concentration of the hydrogen absorbed in the anode and the partial pressures of the remaining gases estimated in step (k), and ( 12 ) Closing the purge valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the third target pressure.

[0026] The hydrogen supply method may further comprise the step (n) of setting a fourth target pressure of the anode with respect to the internal pressure of the anode measured in the step (d) if it is determined in the step (j) that the stop time is longer than the condensation period, the step (o) of determining whether the fourth target pressure exceeds a predetermined maximum allowable pressure, and the step (p) of closing the vent valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the fourth target pressure if it is determined in the step (o) that the fourth target pressure is not higher than the maximum allowable pressure.

[0027] The fourth target pressure may be adjusted so that a concentration of the hydrogen of the anode becomes a predetermined fourth target concentration.

[0028] The hydrogen supply method may further include a step (q) between step (j) and step (n), in which it is determined whether the condensation of the vapor is completed if it is determined in step (j) that the stop period is longer than the condensation period. If it is determined in step (q) that the condensation of the vapor is completed, step (n) may be performed, and if it is determined in step (q) that the condensation of the vapor is being performed, step (k) may be performed.

[0029] Step (q) may include determining whether the internal pressure of the anode measured in step (d) equals or exceeds a predetermined final condensation pressure.

[0030] The hydrogen supply method may further comprise opening the vent valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the maximum allowable pressure when it is determined in step (o) that the fourth target pressure is below the maximum allowable pressure. Character list

[0031] The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings: Fig. 1 is an explanatory view showing a schematic configuration of a fuel cell system; Fig. 2 is a graph illustrating the circumstance of a change in the internal pressure of an anode after stopping the fuel cell system; Fig. 3 is a diagram showing the first to third sections of the diagram from Fig. 2 shows; Fig. 4 is a flowchart illustrating a hydrogen supply method for a fuel cell system according to an embodiment of the present invention; Fig. Figure 5 is a flowchart showing a second variant of the Fig. 4 shows; Fig. 6 is a flowchart showing a third variant of the Fig. 4 shows; and Fig. Figure 7 is a flowchart showing a fourth variant of the Fig. 4 shows. DETAILED DESCRIPTION

[0032] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that throughout the specification, the same or similar reference numerals designate the same or similar components even though they are shown in different drawings. Furthermore, in the following description of the present invention, a detailed description of the known functions and configurations contained herein is omitted if doing so would tend to obscure the subject matter of the present disclosure.

[0033] Furthermore, terms such as first, second, A, B, (a), (b), or the like may be used herein to describe components of the present invention. The terms are used only to distinguish the elements from other elements, and the principal points, sequences, orders, and numbers of the elements are not limited by these terms. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those commonly understood by those skilled in the art familiar with the field to which the present disclosure relates.The terms defined in commonly used dictionaries should be interpreted to have meanings consistent with the meanings of the contexts of related technologies and should not be interpreted as having ideal or overly formal meanings unless they are clearly defined in the description of the present invention.

[0034] Fig. 1 is an explanatory view showing a schematic configuration of a fuel cell system.

[0035] The present invention relates to a hydrogen supply method for a fuel cell system, which provides for the supply of hydrogen to an anode according to the state of a fuel cell system at the start of the fuel cell system. A schematic structure of a fuel cell system is described below with reference to Fig. 1 described.

[0036] The fuel cell system 1can produce a fuel cell stack 10 (hereinafter referred to as "stack 10 ' or 'Stack 10 “), a hydrogen supply device 20 , a hydrogen supply valve 30 , a hydrogen purge valve 40 , an air supply device 50 , an air supply valve 60 , a humidifier 70 and an air release valve 80 include.

[0037] First, the stack 10 a polymer electrolyte membrane 11 , an anode 12 which produces hydrogen ions and electrons through an oxidation reaction of hydrogen, as well as a cathode 13 which generates electrical energy and water through a reduction reaction involving 12 hydrogen ions and electrons moving away, and oxygen in the air coming from an air supply device 50 are involved in the supply.

[0038] The anode12 can have a hydrogen inlet 14 which is equipped with a hydrogen supply line 90 and through which hydrogen is introduced, which is fed through the hydrogen supply line 90 and a hydrogen outlet 15 , which is equipped with a hydrogen return line 100 and through which the hydrogen passing through the anode 12 The hydrogen return line connects 100 the hydrogen outlet 15 and the hydrogen supply line 90 so that the voltage from the anode 12 via the hydrogen outlet 15 discharged hydrogen back to the hydrogen supply line 90 Accordingly, the hydrogen supply device can 20 supplied hydrogen and the hydrogen return line 100 returned hydrogen together via the hydrogen inlet14 be supplied.

[0039] The cathode 13 can have an air inlet 16 which is connected to an air supply line 110 and through which air is supplied, and a humid air outlet 17 , which is connected to a moist exhaust air duct 120 through which moist air, in which the air passing through the cathode 13 and that in the cathode 13 Here the supply air line can be 110 a first air supply line 112 that include atmospheric air and an air inlet 72 of the humidifier 70 connects each other, and a second air supply line 114 which has an air outlet 74 of the humidifier 70 and the air intake 16 the cathode 13 Furthermore, the moist exhaust air duct 120a first moist air discharge line 122 which allow the humid air outlet 17 the cathode 13 and a moist air inlet 76 of the humidifier 70 and a second humid air discharge line 124 which provides a moist air outlet 78 of the humidifier 70 and the outside. Accordingly, the air that the second air supply line 114 after humidification in the humidifier 70 happened, via the air intake 16 and the moist air can be discharged via the moist air outlet 17 into the first moist air discharge line 122 be discharged.

[0040] Furthermore, the hydrogen supply device 20 a hydrogen storage facility 22 in which hydrogen is stored. The hydrogen storage 22 is via the hydrogen supply line 90with the hydrogen inlet 14 the anode 12 and supplies hydrogen, which is used for electricity generation in the stack 10 The hydrogen supplied from the hydrogen storage is fed into the hydrogen inlet 14 the anode 12 introduced and flows along the hydrogen supply line 90 .

[0041] Next, the hydrogen supply valve 30 into the hydrogen supply line 90 installed and can be adjusted by setting the opening degree of the hydrogen supply valve 30 the amount of hydrogen that the anode 12 is supplied.

[0042] Furthermore, the hydrogen purge valve 40 designed to return the hydrogen via the hydrogen return line 100 to the outside. To solve this, the hydrogen return line 100 via the hydrogen purge line 130with the moist exhaust air duct 120 connected, and the hydrogen purge valve 40 is fed into the hydrogen purge line 130 installed to flush the hydrogen purge line 130 to open and close. The hydrogen purge valve 40 the hydrogen purge line 130 selectively open when a predefined hydrogen purge condition is met. The hydrogen purge condition is not specifically limited. For example, the hydrogen purge condition can be linked to whether the hydrogen concentration in the anode 12 corresponds to or falls below a specified reference concentration. If the hydrogen purge line 130 through the hydrogen purge valve 40 is opened, the hydrogen return line can 100 flowing hydrogen, and other gases via the moist exhaust air duct 120 be discharged to the outside after passing through the hydrogen purge line130 to the moist exhaust air duct 120 were submitted.

[0043] Furthermore, the air supply system 50 an air compressor 52 which is located in the first air supply line 112 installed and configured to pump and supply atmospheric air. The air supplied by the air compressor 52 supplied air can enter the air inlet 16 the cathode 13 while passing along the second air supply line 114 flows after being removed from the humidifier 70 was humidified while passing along the first air supply line 112 flowed.

[0044] Next, the air supply valve 60 into the first air supply line 112 installed and can control the amount of air that reaches the cathode 13 is supplied by setting an opening degree of the air supply valve 30 set.

[0045] Furthermore, the humidifier can 70 a hollow fiber humidifier 70 which can humidify air by placing moisture between the air compressor 52 supplied air and the cathode 13 The humidifier 70 can have an air inlet 72 which is connected to the first air supply line 112 connected, an air outlet 74 which is connected to the second air supply line 114 is connected, a moist air inlet 76 which is connected to the first wet discharge line 122 connected, and a moist air outlet 78 which is connected to the second wet discharge line 124 After the exchange of moisture between the air inlet and the 72 introduced air and the air inlet 76 introduced moist air and the air humidification, the humidifier discharges 70the air through the air outlet 74 and discharges the moist air through the air outlet 78 .

[0046] Next, the air release valve 80 in the second moist air outlet line 124 installed and can reduce the emissions of moist air coming from the moist air outlet 17 and the hydrogen and other gases coming from the hydrogen purge line 130 supplied by adjusting the degree of opening of the air release valve 80 regulate.

[0047] Fig. Figure 2 is a graph showing the change in the internal pressure of an anode after stopping the fuel cell system. Fig. 3 is a diagram showing the first to third sections of the diagram of Fig. 2. Here is Fig. 2 a view showing the fact of the change of an internal pressure p a the anode 12when a relatively long time passes after the fuel cell system has stopped. Furthermore, Fig. 3 a view showing the fact of the change of an internal pressure p a the anode 12 when a relatively short time passes after the fuel cell system has stopped.

[0048] If the fuel cell system 1 is stopped, the internal pressure of the anode changes 12 and the composition of the inside of the anode 12 accommodated gases corresponding to a total stop time T s which, after the fuel cell system has stopped 1 Accordingly, as in Fig. 2, the stop time T s be divided into sections one ① to four ④, depending on the internal pressure p a of the stack 10 and the composition of the inside of the stack 10 housed gases.

[0049] The first section ① can be, for example, as in Fig. 3, a section of the total stopping time T s of the fuel cell system 1 between a starting time T 0 , where the fuel cell system 1 is stopped, and an end time of a given reaction time T r The reaction time T r refers to a period of time consumed to complete a reaction of hydrogen stored in the anode 12 and oxygen, which in the cathode 13 contained in the fuel cell system (hereinafter referred to as “reaction of residual hydrogen and residual oxygen”) after the fuel cell system 1 was stopped.

[0050] The reaction of the residual hydrogen with the residual oxygen is completed in a relatively short time. Accordingly, as the reaction of the residual hydrogen and the residual oxygen progresses, phenomena such as the permeation of the gases through the polymer electrolyte membrane rarely occur. 11 , the condensation of steam and the introduction of outside air through the valves 60 and 80 and other components.

[0051] However, all the residual hydrogen is consumed by the reaction of the residual hydrogen and the residual oxygen and the residual oxygen remains, the residual oxygen can 10damage. To achieve this, the amount of residual hydrogen and residual oxygen remaining in the stack when the fuel cell system is stopped is usually adjusted so that all the residual oxygen is consumed and only the residual hydrogen remains when the residual hydrogen and the residual oxygen react.

[0052] As in the Fig. 3, since the reaction of the residual hydrogen and the residual oxygen dominates in the first section ①, the internal pressures p a the anode 12 and the cathode 13 rapidly. When the first stage ① is completed, part of the residual hydrogen, steam, etc. in the anode 12 housed and nitrogen and other existing gases are released when the fuel cell system is stopped in the cathode 13while all residual oxygen is consumed. Accordingly, at the end of the first section ①, the internal pressure p a the anode 12 the lowest in the entire stop time T s of the fuel cell system 1 .

[0053] For example, as in Fig. 3, the second section ② a section of the total stop time T s of the fuel cell system 1 between an end time of the reaction time T described above r and an end time of a given crossing time T o The crossing time T o refers to a period of time consumed to reduce the pressures of the anode 12 and the cathode 13 by balancing the anode 12 hydrogen is introduced without passing through the polymer electrolyte membrane 11 with oxygen in the cathode 13to react, and by nitrogen and other gases present in the cathode 13 contained, if the fuel cell system 1 in the anode 12 through the polymer electrolyte membrane 11 is stopped.

[0054] Generally, the crossing of hydrogen and nitrogen is completed before the condensation of steam and the introduction of outside air through the valves 60 and 80 and other components. Since the time required for the crossing of hydrogen and nitrogen is longer than the time required for the reaction of the residual hydrogen and the residual oxygen with each other, the crossing of hydrogen and nitrogen rarely occurs in the first section 1. Accordingly, as shown in Fig. 3, since in the second section ② the crossing of hydrogen and nitrogen dominates, the internal pressure p a the anode 12by the cathode 13 supplied nitrogen gradually. Since the second section ② is relatively long compared to the first section ①, the rate of increase of the internal pressure p a the anode 12 in the second section ② relatively slow compared to the rate of increase of the internal pressure p a the anode 12 in the first section ①. When the second section ② is completed, hydrogen, nitrogen and steam are mainly inside the anode 12 housed.

[0055] The third section ③ can be, for example, as in Fig. 3, a section of the total stop time T s of the fuel cell system 1 between an end time of the crossing period T described above o and an end time of a given condensation period T c The condensation time T crefers to a period of time required to change the voltage in the anode 12 to condense the vapor contained therein.

[0056] In general, the anode 12 to condense the steam after hydrogen and nitrogen cross each other. In this way, during the period when the steam condenses, a phenomenon may occur in which outside air and other elements are forced through the valves 60 and 80 in the stacks 10 However, the amount of outside air that enters the stack 10 introduced while the steam is condensed, significantly less than the amount of condensed steam S c Accordingly, as in Fig. 3, because the condensation of steam dominates in the third section 3, the internal pressure p a the anode 12gradually decreases according to the condensation of the steam. Since the third section 3 is relatively long compared to the second section 2, the rate of decrease of the internal pressure p a the anode 12 in the third section ③ relatively slow compared to the rate of increase of the internal pressure p a the anode 12 in the second section ( 2 ). When the third section 3 is completed, hydrogen and nitrogen are mainly inside the anode 12 housed.

[0057] For example, in Fig. 2, the fourth section ④ can be a section of the total stop time period T s of the fuel cell system 1 after the end of the specified condensation period T c be.

[0058] Basically, when the fuel cell system is shut down 1 the supply air line 110 and the moist air outlet line 120through the supply air valve 60 or the air release valve 80 closed. However, since the sealing performance of the supply air valve 60 and the air release valve 80 have a predetermined limit, the outside air that is released when the fuel cell system is stopped 1 through the supply air valve 60 and the air release valve 80 through the supply air duct 110 and the exhaust air duct 120 into the cathode 13 Furthermore, the nitrogen that is fed into the cathode 13 introduced outside air via the polymer electrolyte membrane 11 into the anode 12introduced. The introduction phenomenon of outside air occurs continuously throughout the first to fourth sections 1 to 4. However, since the reaction of residual hydrogen and residual oxygen, the crossing of hydrogen and nitrogen, the condensation of steam, and the like dominate in the first to third sections 1 to 3, the influence of outside air on the change of internal pressure p a the anode 12 and the change in the composition of the inside of the anode 12 Meanwhile, as the introduction of outside air dominates in the fourth section 4, the internal pressure p a the anode 12 through the outside through the valves 60 and 80 supplied nitrogen gradually. Accordingly, the internal pressure p a the anode 12 in the fourth section ④ higher than the internal pressure p a the anode 12in the third section ③, and the concentration C a of the hydrogen of the anode 12 in the fourth section ④ is lower than the concentration C a the anode 12 in the third section ③.

[0059] Fig. 4 is a flowchart showing a hydrogen supply process for a fuel cell system 1 illustrated according to an embodiment of the present invention;

[0060] The hydrogen supply method for a fuel cell system according to the embodiment of the present disclosure may include applying a start signal for starting the fuel cell system 1 ( S10 ), measuring a stop time T s , which takes time until the fuel cell system 1 after stopping the fuel cell system 1 is started ( S20 ), measuring an internal pressure p a an anode 12 ( S30), Determine whether a reaction time period T r, which during the completion of a reaction of residual hydrogen and residual oxygen, which in a stack 10 after stopping the fuel cell system 1 present, the stop time T s corresponds to that in step S20 ( S40 ) and supplying hydrogen to the anode 12 according to a predetermined first mode ( S50 ) if in step S40 it is determined that the stop time T s is smaller than the reaction time T r is.

[0061] First, in step S10 determine whether a fuel cell control system of the fuel cell system 1 A start signal is present. The start signal is not specifically limited. The start signal can be, for example, a touch signal, a brake pedal off signal, an accelerator pedal on signal, and the like.

[0062] Then in step S20 after a period of time that elapses until after the fuel cell system has stopped 1 a start signal is applied to the controller, the measured time period is reduced to a stop time period T s set.

[0063] Then in step S30 the internal pressure p a the anode 12 measured using a pressure sensor (not shown) which is located in the stack 10 is installed.

[0064] Next, in step S40 the reaction time T stored in advance in the control unit r and those in step S20 measured stop time T s be compared.

[0065] Afterwards, in step S50 , if in step S40 it is determined that the stop time T s smaller than the reaction time T r is hydrogen of the anode 12according to a first operating mode, which is controlled in the control unit of the fuel cell system 1 is stored in advance.

[0066] The way in which the first mode is executed is not specifically limited. For example, the first mode can be executed by opening the flush valve 40 , which contains the anode 12 accommodated gases from the anode 12 and the anode 12 Hydrogen can be supplied, is closed so that the internal pressure p a the anode 12 to a predetermined first target pressure P 1 becomes.

[0067] The first target pressure P 1 can be adjusted so that the concentration C a of the hydrogen of the anode 12 by supplying hydrogen to a predetermined first target concentration. Preferably, the first target concentration is a concentration that determines the performance of the fuel cell system1 can be optimally maintained. The initial target concentration can be, for example, 70%.

[0068] Since the first mode is executed when the stop time period T s smaller than the reaction time T r is, the internal pressure p a the anode 12 and the composition of the inside of the anode 12 gases accommodated in the first mode equal to the internal pressure p a the anode 12 and the composition of the inside of the anode 12 accommodated gases in the first section ①. Accordingly, in the first operating mode (the first mode), hydrogen and steam are mainly stored inside the anode 12 Then the amount of the electrolyte in the anode 12 stored hydrogen according to the reaction of the hydrogen and the after stopping the fuel cell system 1oxygen produced. Accordingly, the amount of hydrogen produced in the anode 12 is housed, corresponding to the stop time T s and decreases when the stop time T s and the reaction time T r approach each other.

[0069] Since the crossing of hydrogen and nitrogen and the introduction of outside air in the first mode of operation rarely occur, the interior of the anode is dominated by 12 only the consumption phenomenon of hydrogen through the reaction of hydrogen and oxygen. Although the anode 12 Hydrogen is supplied while the purge valve 40 is closed, there is therefore the possibility that the internal pressure p a the anode 12 a specified maximum permissible pressure P max the anode 12exceeds, during the execution of the first mode. Accordingly, the first mode can be executed in a state in which the vent valve 40 is closed.

[0070] In this context, the control unit estimates, while the flush valve 40 is closed, the amount of hydrogen loss due to the reaction of hydrogen and oxygen, which after the fuel cell system has been terminated 1 is generated, and the concentration C a of the hydrogen of the anode 12 in relation to the internal pressure p a the anode 12 , measured in crotch S20 . Furthermore, after setting a first target pressure P 1 in terms of the amount of hydrogen lost and the concentration of hydrogen at the anode 12 , which were estimated in this way, the concentration C a of the hydrogen of the anode 12to the first target concentration by adding the anode 12 hydrogen so that the internal pressure p a the anode 12 to the first target pressure P1.

[0071] Fig. 5 is a flowchart showing a second mode of operation of the Fig. 4 illustrates this.

[0072] Meanwhile, the hydrogen supply method for a fuel cell vehicle, when in step S40 is determined, further include that the stop time period T s the reaction time T r or exceeds, and determine whether the internal pressure p a the anode 12 , measured in step S20 , a given abnormal pressure P u equals or exceeds ( S60 ) if in step S60 it is determined that the internal pressure p a the anode 12 less than an unusual pressure P uis, determining whether a crossing period T o , which disappears when residual gases that accumulate in the stack 10 by a polymer electrolyte membrane 11 to cross so that the pressures of the anode 12 and the cathode 13 be in an equilibrium state after the fuel cell system 1 was stopped, is not less than the value in step S20 ( S70 ) measured stop time T s , and executing a predetermined second mode ( S80 ) if in step S70 it is determined that the stop time T s is smaller than the crossing time T o .

[0073] First, in step S60 the step S30 measured internal pressure p a the anode 12 and the abnormal pressure P stored in advance in the control unit u The unusual pressure P urefers to a reference pressure to determine whether the supply air valve 60 and the air release valve 80 are normally sealed. If the S30 measured internal pressure p a the anode 12 smaller than the unusual pressure P u can be determined whether the sealing effect of the supply air valve 60 and the air release valve 80 are normal.

[0074] Next, in step S70 , if in step S60 it is determined that the internal pressure p a the anode 12 smaller than the unusual pressure P u is in step S20 measured stop time T s and the crossing time T o be compared.

[0075] Afterwards, in step S80 , if in step S70 it is determined that the stop time T s is smaller than the crossing time T o, the second mode, which is stored in advance in the control unit, can be executed.

[0076] Since the second mode is executed when the stop time period T s the reaction time T r does not fall below and is less than the crossing time T o is, the internal pressure p a the anode 12 and the composition of the inside of the anode 12 gases accommodated in the second mode are identical to the internal pressure p a the anode 12 in the second section ② and the composition of the inside of the anode 12 Accordingly, when performing the second mode, hydrogen, steam and nitrogen are mainly stored inside the anode 12 housed.

[0077] Since the second mode is executed while predominantly the crossing of hydrogen and nitrogen inside the stack 10is carried out, the amount of the gas inside the anode 12 nitrogen is greater when the stop time T s and the crossing time T o approach each other and the concentration C a of the hydrogen of the anode 12 becomes smaller when the stop time T s and the crossing time T o approach each other. Accordingly, it can be estimated that the partial pressures P p the remaining gases of the anode gases 12 with the exception of hydrogen, and at the same time the concentration of hydrogen in the anode 12 becomes lower when the stop time T s and the crossing time T o approach each other. As the hydrogen and nitrogen cross over, the internal pressure p a the anode 12according to the degree of progress of the crossing of hydrogen and nitrogen. In this context, in the second mode, after the partial pressures P p the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen, with reference to the gas in step S30 measured internal pressure p a the anode 12 were estimated, hydrogen of the anode 12 so that the concentration C a the anode 12 to a concentration that is suitable for increasing the performance of the fuel cell system 1 to maintain.

[0078] The step S80 can, for example, include a step to estimate the partial pressures P p the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen, with reference to the internal pressure p a the anode 12 , which in step S30 ( S82) was measured, and to close the purge valve 40 and to supply hydrogen, the amount of which corresponds to the partial pressures P p the step S82 estimated residual gases.

[0079] In step S82 As shown in equation 1, the concentrations of the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen, using the internal pressure p a the anode 12 , measured in crotch S30 , and the concentration C a of the hydrogen of the anode 12 The concentration C a the anode 12 can be achieved by using the anode 12 and the cathode 13 hydrogen and air quantities contained when the fuel cell system is at a standstill 1 , the stop time T s and the speed of crossing of hydrogen and nitrogen. P p = P a − 0.01 C a [ Pa ]

[0080] The step S84 can be a step to set a second target pressure P2 the anode 12 with respect to a predetermined second target concentration of the anode 12 absorbed hydrogen and the partial pressures P p of the remaining gases released in step S82 ( S86 ) and a step to close the purge valve 40 and supply the anode 12 with hydrogen, so that the internal pressure p a the anode 12 to the second target pressure P 2 which is in the anode 12 is set.

[0081] In step S86 As shown in equation 2, a second target pressure P 2 the anode 12 can be adjusted by adjusting the partial pressure P p of the remaining gases released in step S82estimated, and the second target concentration stored in advance in the control unit is used. Preferably, the second target concentration is a hydrogen concentration that determines the performance of the fuel cell system 1 can be optimally maintained. The second target concentration can be, for example, 70%. P 2 = P p 1 − 0.01 C 2 [ Pa ]

[0082] In step S88 the vent valve 40 can be closed and hydrogen from the anode 12 so that the internal pressure p a the anode 12 secondly in step S86 set pressure P2. Since the outside air rarely passes through the valves 60 and 80 and other elements in the stack 10 introduced when the second mode is executed, there is a possibility that the internal pressure p a the anode 12 the maximum permissible pressure P max the anode 12exceeds, although the anode 12 Hydrogen is supplied while the purge valve 40 closed, is small. Accordingly, the step S88 be carried out in a state in which the vent valve 40 is closed. According to step S88 the internal pressure p a the anode 12 a second target pressure P 2 which is less than the maximum permissible pressure, and the hydrogen concentration of the anode 12 can be a second target concentration that affects the performance of the fuel cell system 1 can be optimally maintained.

[0083] Fig. Figure 6 shows a flowchart illustrating a third mode of operation of the Fig. 4 represents.

[0084] Meanwhile, the hydrogen supply method for a fuel cell system, when in step S70 it is determined that the stop time T s the crossing time T onot fall below, include the step of determining whether the concentration period T c which is required to condense the in the anode 12 steam contained in the steam chamber is not less than the steam S20 ( S90 ) measured stop time T s , and executing a predefined third mode of operation ( S100 ), if the step S70 it is determined that the stop time T s is less than the crossing time T o is.

[0085] First, in step S90 which in step S20 measured stop time T s and the condensation time period T stored in advance in the control unit c be compared if in step S70 it is determined that the stopping time Ts is not shorter than the crossing time T o .

[0086] Then in step S90the third operating mode stored in advance in the controller is executed if it is determined in step S100 that the stop time period T s shorter than the condensation period T c is,

[0087] Since the third operation mode is performed when the stop time period T s both the crossing time T o as well as the condensation time period T c does not fall below, the internal pressure p a the anode 12 and the composition of the inside of the anode 12 in the third step mode, the gases are equal to the internal pressure p a the anode 12 in the third section ③ and the composition of the gases inside the anode.

[0088] Since the third mode is executed while the condensation of steam inside the stack 10 predominates, the amount of nitrogen stored inside the anode 12and the amount of steam that is inside the anode 12 becomes smaller when the stop time T s and the condensation time period T c approach each other. Accordingly, it can be estimated that the partial pressures P p the remaining gases of the anode gases 12 , except for hydrogen, decrease and the concentration of hydrogen of the anode 12 simultaneously increases when the stop time T s the condensation period T c In this way, as the condensation of the steam progresses, the internal pressure p a the anode 12 according to the degree of steam condensation. In this regard, in the third operating mode of the anode 12 Hydrogen is supplied in such a way that the concentration C a the anode 12to a concentration that is necessary to maintain the performance of the fuel cell system 1 is suitable after in step S30 the internal pressure p a the anode 12 measured and in step S20 during the stop time T s the set S c of the steam was condensed.

[0089] For example, the step S100 a step to estimate the quantity S c of the stop time T s condensed steam, which in the step S20 ( S101 ) was measured, a step to estimate the partial pressures P p the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen, with reference to the internal pressure p a the anode 12 , measured in crotch S30 and the amount Sc of condensed vapor produced in step S101 ( S103) and a step to supply hydrogen, the amount of which corresponds to the partial pressures P p of the remaining gases that were released in step S103 ( S105 ) were estimated.

[0090] In step S101 can the set S c of the condensed vapor with respect to the internal temperature of the anode 12 be estimated, which is determined by the stack 10 installed temperature sensor (not shown). In general, the amount S c of the condensed vapor with respect to the internal temperature of the anode 12 be estimated if the quantity S c of the steam increases with decreasing atmospheric pressure.

[0091] In step S103 As shown in equation 3, the partial pressures P p the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen, using the method described in step S30measured internal pressure p a the anode 12 and the concentration C a of the hydrogen of the anode 12 The concentration C a the anode 12 can be achieved using the hydrogen and air quantities that are in the anode 12 and the cathode 13 when the fuel cell system 1 is stopped, the stop time T s and the set S c of the condensed steam, which in step S101 is appreciated, be appreciated. P p = P a − 0.01 C a [ Pa ]

[0092] The step S105 can be a step for setting a third target pressure P3 of the anode 12 with respect to a predetermined third target concentration of the anode 12 absorbed hydrogen and the partial pressures P p of the remaining gases released in the step S103 ( S107) and a step to close the purge valve 40 and supply the anode 12 with hydrogen, so that the internal pressure p a the anode 12 thirdly, in step S107 ( S109 ) set target pressure.

[0093] In step S107 As shown in equation 4, a third target pressure P 3 the anode 12 can be adjusted by adjusting the partial pressure P p of the remaining gases released in step S103 estimated, and the third target concentration stored in advance in the control unit is used. Preferably, the third target concentration is a hydrogen concentration that improves the performance of the fuel cell system 1 can be optimally maintained. The third target concentration can be, for example, 70%. P 3 = P p 1 − 0.01 C 3 [ Pa ]

[0094] In step S109the vent valve 40 can be closed and hydrogen from the anode 12 so that the internal pressure p a the anode 12 thirdly in step S107 set pressure P3. Since the outside air rarely passes through the valves 60 and 80 and other components in the stack 10 introduced when the third mode is executed, there is a possibility that the internal pressure p a the anode 12 the maximum permissible pressure P max the anode 12 exceeds, although the anode 12 Hydrogen is supplied while the purge valve 40 closed, is small. Accordingly, the step S109 be carried out in a state in which the vent valve 40 is closed. After the step S109 the internal pressure p a the anode 12 a third target pressure P 3which is less than the maximum permissible pressure, and the hydrogen concentration of the anode 12 can be a third target concentration that affects the performance of the fuel cell system 1 can be optimally maintained.

[0095] Fig. Figure 7 shows a flowchart illustrating a fourth mode of operation from the Fig. 4 explained.

[0096] Meanwhile, the hydrogen supply method for a fuel cell system may also include a step of controlling a predetermined fourth mode ( S110 ) is performed if in step S90 it is determined that the stop time T s the condensation period T c does not fall below.

[0097] Since the fourth mode is executed when the stop time period T s not less than the condensation time T c is, the internal pressure p a the anode 12and the composition of the inside of the anode 12 gases accommodated in the fourth mode are identical to the internal pressure p a the anode 12 and the composition of the inside of the anode 12 accommodated gases in the fourth section ④.

[0098] Since the fourth mode is executed while the outside air supply is controlled by the valves 60 and 80 and other elements predominate, the internal pressure p a the anode 12 with increasing stop time T s and the concentration C a the anode 12 decreases with increasing stop time T s . In this context, the fourth mode can be achieved by adjusting the opening / closing of the vent valve 40 and the amount of the anode 12 supplied hydrogen corresponding to an increase in the internal pressure p a the anode as a result of the supply of outside air.

[0099] For example, the step S110 include a step to determine whether the condensation of the steam is complete ( S111 ), setting a fourth target pressure P 4 in relation to the step S30 ( S112 ) estimated internal pressure p a , if in step S111 it is determined that the condensation of the steam is complete, a step in which it is determined whether the fourth target pressure P 4 , which in step S112 is set, the maximum permissible pressure P max the anode 12 ( S113 ), closing the vent valve 40 and supplying hydrogen to the anode 12 , so that the internal pressure p a the anode 12 to the fourth target pressure P 4 is when in step S112 it is determined that the fourth target pressure P 4 not greater than the maximum permissible pressure Pmax and closing the vent valve 40 and supplying hydrogen to the anode 12 , so that the internal pressure p a the anode 12 to the maximum permissible pressure P max ( S114 ) if in step S113 it is determined that the fourth target pressure P 4 greater than the maximum permissible pressure P max is.

[0100] In step S111 can be determined whether the S30 measured internal pressure p a not less than a specified final condensation pressure P c the anode 12 Here, the final condensation pressure P c an internal pressure p a the anode 12 , when the condensation of the in the anode 12 accommodated steam is completed, and preferably the final condensation pressure P c an internal pressure p a the anode 12 when the third section ③ is completed.

[0101] Even if in step S90 it is determined that the stop time T s the condensation period T c does not fall below, the condensation of the steam in the anode predominates 12 until the condensation of the steam is completed, if the condensation of the steam is not yet completed. If in step S111 it is determined that the internal pressure p a the anode 12 is lower than the final condensation pressure P c , the third operating mode described above ( S100 ) based on the finding that the condensation of the steam is not yet complete.

[0102] If in step S112 it is determined that the internal pressure p a the anode 12 not less than the final condensation pressure P c can be done in step S111 a fourth target pressure P 4 related to the internal pressure pa the anode 12 , measured in crotch S30 , can be set. Using the internal pressure p a the anode 12 the partial pressures P p the remaining gases in the anode 12 accommodated gases, with the exception of hydrogen. The fourth target pressure P 4 can be related to the partial pressures P p of the remaining gases are adjusted so that the concentration C a of the hydrogen of the anode 12 by supplying hydrogen to the anode 12 to a predetermined fourth target concentration. Preferably, the fourth target concentration is a hydrogen concentration that improves the performance of the fuel cell system 1 can be optimally maintained. For example, the fourth target concentration can be 70%.

[0103] In step S113 the fourth target pressure P 4 the step S112adjusted anode 12 with the maximum permissible pressure P max the anode 12 be compared.

[0104] In step S114 can the anode 12 Hydrogen is supplied while the vent valve 40 is closed so that the internal pressure p a the anode 12 fourth in step S112 set target pressure P 4 If the fourth target pressure P 4 the anode 12 not more than the maximum permissible pressure P max the anode 12 the durability of the anode 12 not weakened, although the hydrogen of the anode 12 is supplied in such a way that the concentration C a of the hydrogen of the anode 12 high enough to ensure the performance of the fuel cell system 1 Accordingly, the step S114be carried out in a state in which the vent valve 40 is closed. After the step S114 the internal pressure p a the anode 12 a fourth target pressure P 4 which is lower than the maximum permissible pressure P max and the hydrogen concentration of the anode 12 can be a fourth target concentration that affects the performance of the fuel cell system 1 can be optimally maintained.

[0105] In step S115 can the anode 12 Hydrogen is supplied while the purge valve 40 is opened so that the internal pressure p a the anode 12 to the maximum permissible pressure P max If the fourth target pressure P 4 the anode 12 the maximum permissible pressure P max the anode 12 exceeds the life of the anode 12 be weakened if the hydrogen of the anode12 is supplied in such a way that the internal pressure p a the anode 12 to the fourth target pressure P 4 Accordingly, the step S114 be carried out in a state in which the internal pressure p a the anode 12 to the maximum permissible pressure P max increases and the concentration C a of the hydrogen of the anode 12 with the flush valve open 40 maximum. After the step S115 the internal pressure p a and the concentration C a of the hydrogen of the anode 12 be optimally adjusted without affecting the durability of the anode 12 to impair.

[0106] Meanwhile, the hydrogen supply method for a fuel cell system may further comprise a step in which, when in the step S60 it is determined that the internal pressure p a the anode 12a predetermined abnormal pressure P u exceeds, the flush valve 40 is opened and the anode 12 Hydrogen is added so that the internal pressure p a the anode 12 to the maximum permissible pressure P max ( S120 ) becomes.

[0107] If in step S60 it is determined that the internal pressure p a the anode 12 not less than the abnormal pressure P u the sealing effect of at least one of the valves 60 and 80 become abnormal, so there is a high probability that the outside air is being forced through at least one of the valves 60 and 80 quickly into the anode 12 Accordingly, the step S120 be carried out in a state in which the internal pressure p a the anode 12 to the maximum permissible pressure P maxincreases and the concentration C a of the hydrogen of the anode 12 with the flush valve 40 open. After step S120 the internal pressure p a the anode 12 and the concentration C a of the hydrogen of the anode 12 be optimally adjusted without affecting the durability of the anode 12 to affect:

[0108] In the hydrogen supply method for a fuel cell system, a frequency of hydrogen purging at the start of the fuel cell system 1 be minimized, since hydrogen is only selectively purged when the internal pressure of the anode 12 the maximum permissible pressure P max while hydrogen is released from the anode 12 when starting the fuel cell system 1According to the hydrogen supply method for a fuel cell system, the amount of hydrogen discharged to the outside by purging the hydrogen can be minimized when the fuel cell system 1 is started, the pressure of the hydrogen applied to the anode 12 when starting the fuel cell system 1 can be minimized, and the concentration of hydrogen that is present at the start of the fuel cell system 1 Exhaust gases discharged to the outside can be minimized.

[0109] The hydrogen supply method for a fuel cell system according to the present invention has the following effects.

[0110] First, according to the present invention, a frequency of hydrogen purging at the start of the fuel cell system can be minimized because hydrogen is selectively purged only when the internal pressure of the anode may exceed the maximum allowable pressure while hydrogen is supplied to the anode at the start of the fuel cell system.

[0111] Secondly, the amount of hydrogen discharged to the outside during the start-up of the fuel cell system can be minimized by purging the hydrogen.

[0112] Third, the pressure of the hydrogen supplied to the anode during start-up of the fuel cell system can be minimized.

[0113] Fourthly, the concentration of hydrogen in the exhaust gases discharged to the outside during the start-up of the fuel cell system can be minimized.

[0114] The above description is a simple example of the inventive idea of ​​the present invention, and the present invention can be variously corrected and modified by those skilled in the technical field to which the present disclosure relates without departing from the essential features of the present invention.

[0115] Therefore, the disclosed embodiments of the present invention do not limit the inventive idea, but are illustrative, and the scope of the invention is not limited by the embodiments of the present disclosure. The scope of the present invention is to be interpreted by the claims, and all technical ideas within the range of equivalence are considered to fall within the scope of the present invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] KR 1020170084349

[0001]

Claims

[1] A hydrogen supply method for a fuel cell system for supplying hydrogen according to a state of the fuel cell system when the fuel cell system is started, the hydrogen supply method comprising the following steps: a) measuring a stop time period that elapses until the fuel cell system is restarted after the fuel cell system has been stopped; (b) determining whether a reaction time required to complete a reaction of residual hydrogen and residual oxygen contained in a fuel cell stack since the fuel cell system is stopped is not longer than the stop time; and (c) closing a purge valve capable of discharging gases accommodated in an anode from the anode and simultaneously supplying hydrogen to the anode so that an internal pressure of the anode becomes a predetermined first target pressure when it is determined in step (b) that the stop period is shorter than the reaction period. [2] The hydrogen supply method according to claim 1, wherein the predetermined first target pressure is set so that a concentration of hydrogen in the anode becomes a predetermined first target pressure concentration. [3] A hydrogen supply method according to claim 1, further comprising, prior to step (b), a step (d) comprising: (d) Measuring the internal pressure of the anode. [4] A method for supplying hydrogen according to claim 3, further comprising the steps of: (e) determining whether the internal pressure of the anode measured in step (d) is less than a predetermined abnormal pressure; and (f) opening the purge valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes a predetermined maximum allowable pressure when it is determined in step (e) that the internal pressure is not less than the predetermined abnormal pressure. [5] The hydrogen supply method according to claim 3, further comprising: (g) determining whether a crossing time for which residual gases present in the fuel cell stack cross through a polymer electrolyte membrane and the anode and the cathode are in pressure equilibrium after stopping the fuel cell system is not less than the stopping time period when it is determined in step (e) that the internal pressure of the anode is less than the predetermined abnormal pressure; (h) estimating the partial pressures of the remaining gases, excluding hydrogen, accommodated in the anode by reference to the internal pressure of the anode measured in (d), if it is determined in step (g) that the stopping time is less than the crossing time; and (i) closing the vent valve and simultaneously supplying to the anode a quantity of hydrogen corresponding to the partial pressures of the other gases estimated in step (h). [6] A hydrogen supply method according to claim 5, wherein step (i) comprises: (i1) setting a second target pressure of the anode in relation to a predetermined second target concentration of the hydrogen absorbed in the anode and the partial pressures of the remaining gases estimated in step (h); and (i2) Closing the vent valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the second target pressure. [7] The hydrogen supply method according to claim 6, further comprising: (j) determining whether a condensation period required to complete the condensation of vapor present in the anode when the fuel cell system is stopped is equal to or longer than the stop period if it is determined in step (g) that the stop period is equal to or longer than the crossing time; (k) estimating the partial pressures of the remaining gases, excluding hydrogen, of the gases accommodated in the anode if it is determined in step (j) that the stop period is shorter than the condensation period; and (1) Closing the vent valve and simultaneously supplying to the anode a quantity of hydrogen corresponding to the partial pressures of the other gases estimated in step (k). [8] A hydrogen supply method according to claim 7, wherein step (k) comprises: Estimation of the partial pressures of the remaining gases with respect to the internal pressure of the anode measured in step (d). [9] A hydrogen supply method according to claim 8, further comprising: (m) estimating an amount of the vapor accommodated in the anode which has been condensed during the stop period between step (j) and step (k), wherein step (k) further comprises: Estimation of the partial pressures of the remaining gases with respect to the internal pressure of the anode measured in step (d) and the amount of condensed vapor estimated in step (m). [10] A hydrogen supply method according to claim 9, wherein step (m) comprises: Estimation of the amount of condensed vapor in relation to the internal pressure of the anode. [11] A hydrogen supply method according to claim 7, wherein step (1) comprises: (11) setting a third target pressure of the anode in relation to a predetermined third target concentration of the hydrogen accommodated in the anode and the partial pressures of the remaining gases estimated in step (h); and (12) Close the vent valve and simultaneously supply the hydrogen to the anode so that the internal pressure of the anode becomes the third target pressure. [12] The hydrogen supply method according to claim 7, further comprising: (n) setting a fourth target pressure of the anode with respect to the internal pressure of the anode measured in step (d) if it is determined in step (j) that the stop period is longer than the condensation period; (o) determining whether the fourth target pressure exceeds a predetermined maximum allowable pressure; and (p) closing the purge valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the fourth target pressure if it is determined in step (o) that the fourth target pressure does not exceed the maximum allowable pressure. [13] The hydrogen supply method according to claim 12, wherein the fourth target pressure is adjusted so that the hydrogen concentration of the anode assumes the preset fourth target concentration. [14] The hydrogen supply method according to claim 12, further comprising: (q) determining whether the condensation of the vapor is completed between step (j) and step (n) if it is determined in step (j) that the stop time period is longer than the condensation period, wherein if it is determined in step (q) that the condensation of the vapor is completed, step (n) is performed, and wherein, if it is determined in step (q) that the condensation of the vapor is continuing, step (k) is carried out. [15] A hydrogen supply method according to claim 14, wherein step (q) comprises: Determine whether the internal pressure of the anode measured in step (d) equals or exceeds a specified final condensation pressure. [16] The hydrogen supply method according to claim 12, further comprising: Opening the vent valve and simultaneously supplying hydrogen to the anode so that the internal pressure of the anode becomes the maximum allowable pressure if it is determined in step (o) that the fourth target pressure is lower than the maximum allowable pressure.

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