JP2016024924A - Method of starting fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery system starting method that enables short-time arrival at operation temperature when the system is started.SOLUTION: In a fuel battery system 1 having a battery stack 13 containing a film electrode assembly 131, fuel supply means 113 for supplying liquid fuel to an anode of the battery stack, oxidant supply means 117 for supplying oxidant to a cathode of the battery stack, temperature detecting means 126 for detecting the temperature of the battery stack, and a battery 14 for supplying power to the fuel supply means and the oxidant supply means. When the temperature of the battery stack is less than a predetermined temperature at the start time of the fuel battery system, the actual power generation voltage of the battery stack is controlled to a voltage lower than the rated power generation voltage until at least the temperature of the battery stack reaches the predetermined temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for starting a fuel cell system.

  A polymer electrolyte fuel cell (PEFC) generates electricity by supplying an oxidant such as air to the cathode and a reducing fuel such as hydrogen gas to the anode with an ion exchange membrane in between. In addition, when hydrogen remains in the fuel cell after power generation is stopped, freezing occurs. Therefore, when power generation is stopped, nitrogen gas is supplied to one or both of the anode and the cathode to purge water (Patent Document 1). ).

JP 2011-151043 A

  By the way, in a direct methanol fuel cell (DMFC) that generates power using methanol as fuel, the output power is low when the fuel cell temperature is low, so the fuel cell temperature (system operating temperature) is 60 to 85 ° C. Is preferred. However, if the operating temperature is not reached when the fuel cell temperature is low and the operating temperature is not reached, a warm-up operation is required due to the reaction waste heat of the fuel cell. There was a problem.

  The problem to be solved by the present invention is to provide a method for starting a fuel cell system that can reach an operating temperature in a short time when the fuel cell system is started.

The present invention provides a battery stack including a membrane electrode assembly, fuel supply means for supplying liquid fuel to the anode of the battery stack, oxidant supply means for supplying an oxidant to the cathode of the battery stack, and the battery stack. A fuel cell system comprising: temperature detection means for detecting the temperature of the battery; and a battery for supplying power to the fuel supply means and the oxidant supply means.
When the temperature of the battery stack is lower than a predetermined temperature when the fuel cell system is started up, the actual power generation voltage of the battery stack is a voltage lower than the rated power generation voltage until at least the temperature of the battery stack reaches the predetermined temperature. The above-mentioned problem is solved by controlling to the above.

The energy conversion efficiency η in the fuel cell is represented by the product of the voltage efficiency η _v and the current efficiency η _j . Since the voltage efficiency η _v is the ratio of the actual power generation voltage Vw to the theoretical power generation voltage Vt, the actual power generation voltage is The energy conversion efficiency approaches 100% as it approaches the theoretical power generation voltage. This means that the lower the actual power generation voltage is, the lower the energy conversion efficiency is and the amount of heat generated by the power generation reaction is increased. According to the present invention, when the battery stack is at a low temperature when the fuel cell system is started, the actual power generation voltage of the battery stack is maintained at a voltage lower than the rated power generation voltage until the temperature is raised to a predetermined temperature. Can be efficiently used to raise the temperature of the battery stack. As a result, the battery stack reaches the operating temperature in a short time. Thereby, the auxiliary | assistant battery used at the time of starting can be made into the thing of the minimum capacity | capacitance.

1 is a block diagram showing a fuel cell system according to an embodiment of the present invention. It is a flowchart which shows the process sequence in the control apparatus of FIG. It is a graph which shows the relationship of the power generation voltage and the power density with respect to the current density in 28 degreeC of a direct methanol fuel cell. It is a graph which shows the relationship between the starting time in Example 1 and its comparative example 1 of this invention, and generated electric power.

  Hereinafter, a fuel cell system 1 according to an embodiment of the present invention is a direct methanol fuel cell system that generates power using methanol as a liquid fuel. As shown in FIG. A device 12, a fuel cell 13, and a battery 14 are provided, and power is supplied to the power load 2. Hereinafter, each configuration will be described with reference to FIG.

  The fuel cell 13 includes a membrane-electrode assembly (MEA) 131, a plate-like anode separator 135 and a cathode separator 136 that sandwich the membrane-electrode assembly 131. The membrane electrode assembly 131 includes a substantially rectangular polymer electrolyte membrane 132 having hydrogen ion (cation) conductivity, a substantially rectangular anode catalyst layer 133, and a cathode catalyst layer 134, and further illustration is omitted. A substantially rectangular anode gas diffusion layer and cathode gas diffusion layer are included. The anode catalyst layer 133 and the anode gas diffusion layer constitute an anode (fuel electrode), and the cathode catalyst layer 134 and the cathode gas diffusion layer constitute a cathode (air electrode).

  The polymer electrolyte membrane 132 is not particularly limited, and a polymer electrolyte membrane mounted on a normal polymer electrolyte fuel cell can be used. For example, a polymer electrolyte membrane made of perfluorocarbon sulfonic acid (for example, Nafion (trade name) manufactured by DuPont, USA, Aciplex (trade name) manufactured by Asahi Kasei Co., Ltd., GSII manufactured by Japan Gore-Tex Co., Ltd., etc.) Can be used.

  The anode catalyst layer 133 and the cathode catalyst layer 134 are made of, for example, an electrode catalyst such as a platinum-based metal catalyst, conductive carbon particles (carbon powder) supporting the electrode catalyst, and a polymer electrolyte having hydrogen ion conductivity. It is configured.

  As the conductive carbon particles that are carriers in the anode catalyst layer 133 and the cathode catalyst layer 134, it is preferable to use a conductive carbon material having developed pores, such as carbon black, activated carbon, carbon fiber, and carbon tube. Can be used. Examples of carbon black include channel black, furnace black, thermal black, and acetylene black. Activated carbon can be obtained by carbonizing and activating materials containing various carbon atoms.

  As an electrode catalyst in the anode catalyst layer 133 and the cathode catalyst layer 134, it is preferable to use platinum or a platinum alloy. Platinum alloys include platinum group metals other than platinum (ruthenium, rhodium, palladium, osmium, iridium), iron, titanium, gold, silver, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, and tin. An alloy of platinum and one or more metals selected from the group is preferably used. The platinum alloy may contain an intermetallic compound of platinum and the metal. Furthermore, an electrode catalyst mixture obtained by mixing an electrode catalyst made of platinum and an electrode catalyst made of a platinum alloy may be used, or the same electrode catalyst may be used on the anode side and the cathode side, or different electrode catalysts may be used. .

  As the anode gas diffusion layer and the cathode gas diffusion layer (both not shown) disposed outside the anode catalyst layer 133 and the cathode catalyst layer 134, various gas diffusion layers known in the art can be used. . As the base material that constitutes these gas diffusion layers, in order to give gas permeability, the conductive material made using carbon fine powder, pore former, carbon paper or carbon cloth having a developed structure structure. A porous porous substrate can be used. In order to improve drainage, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetra A water-repellent material (polymer) typified by a fluororesin such as fluoroethylene / ethylene copolymer (ETFE) may be dispersed inside the base material, and the base material may be subjected to a water-repellent treatment. . Furthermore, in order to give electronic conductivity, you may comprise the said base material with electronic conductive materials, such as a carbon fiber, a metal fiber, or a carbon fine powder. The same gas diffusion layer or different gas diffusion layers may be used on the cathode side and the anode side.

  The pair of anode separator 135 and cathode separator 136 are members that are disposed outside the membrane electrode assembly 131 and mechanically fix the membrane electrode assembly 131. The surface of the anode separator 135 that is in contact with the membrane electrode assembly 131 is supplied with methanol, which is a liquid fuel, to the anode to carry away the electrode reaction products and substances including unreacted methanol from the reaction field to the outside. Similarly, the surface of the cathode separator 136 that is in contact with the membrane electrode assembly 131 is supplied with oxygen (air) as an oxidant to generate an electrode reaction. A cathode flow path (not shown) is formed for carrying away substances and substances including unreacted methanol from the reaction field to the outside.

  Although not shown, the anode channel and the cathode channel are formed by providing grooves on the surfaces of the anode separator 135 and the cathode separator 136, respectively, by a conventional method. Although not particularly limited, the anode channel and the cathode channel are, for example, a serpentine composed of a plurality of linear grooves and a plurality of turn-shaped grooves connecting the adjacent linear grooves from upstream to downstream. Has a shape.

In the fuel cell 13 configured as described above, methanol is supplied to the anode supply part 135A of the anode separator 135 via the first flow path 112, and the third flow path 116 is supplied to the cathode supply part 136A of the cathode separator 136. When supplying air through the anode,
[Equation 1]
CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻
The chemical reaction occurs, and at the cathode,
[Equation 2]
3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O
A chemical reaction occurs. As a result, a current flows between the anode and the cathode.

  The carbon dioxide gas generated at the anode and unreacted methanol that has not contributed to the reaction are returned to the first tank 111 from the anode discharge part 135B via the second flow path 114. Similarly, water generated at the cathode and unreacted methanol that has permeated (crossed over) the membrane electrode assembly 131 are returned to the third tank 120 from the cathode discharge portion 136B via the fourth flow path 118 and the condenser 119. It is.

  The fuel cell 13 shown in the figure is an example constituted by a single membrane electrode assembly 131, but a plurality of membrane electrode assemblies 131 are provided depending on the power required for the power load 2 and the rated power of the battery 14. A battery stack may be formed by stacking in series and / or in parallel. Hereinafter, a fuel cell including one or a plurality of membrane electrode assemblies 131 is collectively referred to as a cell stack 13.

  The fuel supply device 11 as fuel supply means includes a first tank 111, a second tank 123, and a third tank 120. The first tank 111 stores an aqueous methanol solution supplied to the fuel cell 13. The second tank 123 stores a methanol aqueous solution or a methanol stock solution whose concentration is higher than the concentration of the methanol aqueous solution stored in the first tank, and the third tank 120 is connected to the cathode of the fuel cell 13 as described above. Returned and liquefied water (partly containing methanol) is stored.

  The aqueous methanol solution stored in the first tank 111 is supplied to the anode supply part 135A of the fuel cell 13 by the first pump 113 provided in the first flow path 112 via the first flow path 112 such as a pipe. . The first pump 113 is operated by electric power supplied from the battery 14 or the fuel cell 13, and its operation and stop are controlled by a control signal from the control device 12. The two-dot chain line in FIG. 1 indicates a power supply line, and the dotted line indicates a signal line for a control signal. In addition, these flow paths 112, 114, 116, 118, 121, including a second flow path 114, a third flow path 116, a fourth flow path 118, a fifth flow path 121, and a sixth flow path 124, which will be described later. , 124 can adopt a specific structure such as a pipe or a passage according to the size or layout of the fuel cell system 1. In addition, unreacted methanol and carbon dioxide gas are returned to the first tank 111 from the anode discharge part 135B of the fuel cell 13 via the second flow path 114, but the gas phase carbon dioxide gas floats on the liquid surface. The first tank 111 substantially separates liquid phase methanol and gaseous phase carbon dioxide, and the carbon dioxide gas is discharged out of the fuel cell system 1 through an exhaust passage (not shown).

  A methanol stock solution or a high-concentration aqueous methanol solution (hereinafter also referred to as additional methanol) stored in the second tank 123 is a sixth flow path 124 such as a pipe provided between the second tank 123 and the first tank 111. Is supplied to the first tank 111 by the second pump 125 provided in the sixth flow path 124. The second pump 125 is operated by electric power supplied from the battery 14 or the fuel cell 13 (illustration of the power supply line is omitted), and its operation and stop are controlled by a control signal from the control device 12. The water stored in the third tank 120 (partly containing methanol) passes through the fifth channel 121 such as a pipe provided between the third tank 120 and the first tank 111. It is supplied to the first tank 111 by a third pump 122 provided in the five flow paths 121. The third pump 122 is operated by electric power supplied from the battery 14 or the fuel cell 13 (illustration of the power supply line is omitted), and its operation and stop are controlled by a control signal from the control device 12.

  The cathode supply portion 136A of the fuel cell 13 is provided with a third flow path 116 such as a pipe or a passage, and external air is provided by a blower 117 provided in the third flow path 116 via the third flow path 116. (Oxygen that becomes an oxidizing agent) is inhaled. The third channel 116 is provided with a filter 115 that removes dust and the like contained in the air. Therefore, the blower 117 and the filter 115 are oxidant supply means for supplying an oxidant to the cathode. The blower 117 is operated by electric power supplied from the battery 14 or the fuel cell 13, and its operation and stop are controlled by a control signal from the control device 12.

  A condenser for controlling the water vapor generated at the cathode to be liquefied and returned to the third tank 120 is provided in the fourth flow path 118 provided between the cathode discharge part 136B of the fuel cell 13 and the third tank 120. 119 is provided.

  Each membrane electrode assembly 131 of the battery stack 13 is provided with a temperature sensor 126 as temperature detection means, detects the temperature of each membrane electrode assembly 131, and outputs a detection signal to the control device 12. The control device 12 calculates the average value or the minimum temperature of each membrane electrode assembly 131 based on the read detection signal. Note that the temperature sensors 126 may not be provided in all the membrane electrode assemblies 131 but may be provided only in the main membrane electrode assemblies 131 or may be provided in the membrane electrode assemblies 131 at a predetermined interval.

  The battery 14 is, for example, a secondary battery, and supplies power to the first pump 113 and the blower 117 when the fuel cell system 1 is started as described later, and generates power from the fuel cell 13 during start-up and during steady operation. It manages the function to compensate for the power shortage. The battery 14 may supply power to the second pump 125 and the third pump 122. The battery 14 is charged by supplying surplus power from the fuel cell 13 when there is surplus power when the fuel cell 13 is in steady operation.

  The power load 2 is a load driven by the power from the fuel cell 13 and the battery 14 connected in parallel, and power is supplied to the power load 2 so that the fuel cell 13 is a main power source and the battery 14 is a subordinate power source. A power selector switch may be provided on the line, and the controller 12 may control the selector switch.

  The control device 12 includes a start and stop switch for the fuel cell 13 as an input unit, and outputs a control signal for operating the first pump 113 and the blower 117 when the start switch is turned ON (the stop switch is OFF). . When the stop switch is turned on (the start switch is turned off), a control signal for stopping the first pump 113 and the blower 117 is output to each. The control device 12 is operated by a power source such as a battery (not shown). The specific control procedure is as follows.

  FIG. 2 is a flowchart showing a control procedure executed by the control device 12 of the fuel cell system 1 of this example, and a series of processing is repeated at a preset time interval. It should be noted that the illustrated control procedure shows only the procedure for starting and stopping the fuel cell system 1 of the present example, and omits the concentration management and other control procedures during steady operation.

  First, in step ST1, when the ON signal of the start switch is input to the control device 12, the process proceeds to step ST2, the detection signal from the temperature sensor 126 is read, and the detected temperature of the battery stack 13 is the lower limit value of the operating temperature 60. Judge whether it is less than ℃. In the fuel cell system 1 of this example, the steady operation temperature is set to 60 ° C. to 85 ° C., but the present invention is not limited to this. When the detected temperature of the battery stack 13 is 60 ° C. or higher in step ST2, the process proceeds to step ST5 without performing the operation under the start condition in step ST3. This is because if the temperature drop of the battery stack 13 is not large and the steady operation condition is satisfied, such as when the fuel cell system 1 is restarted shortly after stopping, it is not meaningful to apply the start condition with low energy conversion efficiency. Although illustration is omitted, there may be provided a step of prohibiting activation of the fuel cell system 1 by judging that there is some abnormality when the detected temperature exceeds 85 ° C. which is the upper limit value of the steady operating temperature. Good.

  On the other hand, when the detected temperature of the battery stack 13 is lower than 60 ° C. in step ST2, the process proceeds to step ST3, and an operation signal based on the start condition is output to the first pump 113 and the blower 117. Here, the starting condition and the steady operating condition of this example will be described.

The energy conversion efficiency η in the fuel cell is represented by the product of the voltage efficiency η _v and the current efficiency η _j .
[Equation 3]
η = η _v × η _j
Since the voltage efficiency η _v is a ratio of the actual power generation voltage Vw to the theoretical power generation voltage Vt (η _v = Vw / Vt), when the energy conversion efficiency η is expressed using the actual power generation voltage Vw,
[Equation 4]
η = (Vw / Vt) × η _j

  That is, the energy conversion efficiency η approaches 100% as the actual power generation voltage Vw is closer to the theoretical power generation voltage Vt. This means that the lower the actual power generation voltage Vw, the lower the energy conversion efficiency η, and the greater the amount of heat generated by the power generation reactions of Equations 1 and 2 above. That is, in the fuel cell system 1 of this example, when the temperature of the battery stack 13 is less than 60 ° C., the fuel cell system 1 is intentionally started under the condition that the energy conversion efficiency is low, and the heat generated by the power generation reaction is This is effectively utilized as the temperature rising energy during the warm-up operation of the stack 13.

  Specifically, when the actual power generation voltage Vw during steady operation (steady operation conditions) is controlled at 0.4 V to 0.5 V, the actual power generation voltage Vw as a starting condition during warm-up operation is lower than this. 0.2V to 0.4V, preferably 0.25V to 0.35V.

FIG. 3 is a graph showing the relationship between the power generation voltage (V) and the power density (mW / cm ² ) with respect to the current density (A / cm ² ) at 28 ° C. of the direct methanol fuel cell. Table 1 below shows the power generation voltage at room temperature. It is a table | surface which shows the example of a relationship between (V) and power density (mW / cm < ² >).

  As shown in FIG. 3 and Table 1, when the current density increases, the generated voltage decreases and the power density increases. However, when the generated voltage decreases as shown in the relational expression 4 above, the energy conversion efficiency also decreases. In setting the steady operation condition of the fuel cell system 1, it is necessary to consider the balance between the energy conversion efficiency and the power density. Therefore, as the steady operation condition of this example, the actual power generation voltage Vw is set to 0. It is set to 4V to 0.5V. For this reason, the actual power generation voltage Vw of the starting condition is set to 0.2 V to 0.4 V, preferably 0.25 V to 0.35 V, lower than the steady operating condition. If the voltage is lower than 0.2 V, the catalyst may be deteriorated. On the other hand, if the voltage exceeds 0.4 V, the warm-up speed becomes slow.

  In order to operate the fuel cell system 1 under a starting condition in which the actual power generation voltage Vw is 0.2V to 0.4V lower than the steady operating condition, for example, the flow rate of the aqueous methanol solution by the first pump 113 and / or the air flow by the blower 117 What is necessary is just to reduce a flow volume from those of steady operation conditions. As a result, the aqueous methanol solution stored in the first tank 111 is supplied to the anode of the fuel cell 13 via the first flow path 112, and external air is supplied to the fuel cell via the third flow path 116 and the filter 115. 13 is supplied to the cathode 13 and power generation by the fuel cell 13 is started. However, since the fuel cell system 1 operates under a condition where the energy conversion efficiency is low, as described above, the heat generation amount of the power generation reaction in the membrane electrode assembly 131 is increased as compared with that in the steady operation, thereby the cell stack (fuel cell) 13. The temperature rise time can be shortened.

  Returning to FIG. 2, in step ST <b> 4, the detection signal from the temperature sensor 126 is read again, and it is determined whether or not the detected temperature of the battery stack 13 is less than 60 ° C., which is the lower limit value of the operating temperature. Then, the operation under the start condition in step 3 and the temperature confirmation in step ST4 are repeated until the detected temperature of the battery stack 13 becomes 60 ° C. or higher. Although illustration is omitted, there may be provided a step of prohibiting activation of the fuel cell system 1 by judging that there is some abnormality when the detected temperature exceeds 85 ° C. which is the upper limit value of the steady operating temperature. Good.

  In step ST4, when the detected temperature of the battery stack 13 reaches 60 ° C. or higher, the process proceeds to step ST5, and the operation of the fuel cell system 1 under steady operating conditions is performed. Specifically, for example, the flow rate of the methanol aqueous solution by the first pump 113 and / or the flow rate of the air by the blower 117 may be increased from those of the start condition. As a result, the fuel cell system 1 operates in a state where the energy conversion efficiency and the power density are balanced.

  In step ST6 in which the fuel cell system 1 is operating, when a stop switch ON signal is input to the control device 12, the process proceeds to step ST7, and a stop signal is output to the first pump 113 and the blower 117. Thereby, the supply of further methanol aqueous solution to the anode is stopped and the supply of further air to the cathode is stopped.

  As described above, according to the fuel cell system 1 of the present example, when the fuel cell system 1 is started, the operation is controlled so that the actual power generation voltage Vw of the battery stack 13 is lower than the generated power during steady operation. Further, the amount of heat generated by the membrane electrode assembly 131 is increased from that during steady operation, and the temperature can be raised to the temperature during steady operation in a short time. As a result, the capacity of the battery 14 for supplementing the total power to be supplied to the power load 2 can be minimized.

  Next, a more specific example and a comparative example for the example will be described that the startup procedure of the fuel cell system 1 of the present invention contributes to shortening of the startup time of the fuel cell system 1. However, various conditions such as numerical values and materials in the following examples are merely examples of the present invention and do not limit the present invention.

Example 1
As the polymer electrolyte membrane 132, a polymer electrolyte membrane made of perfluorocarbon sulfonic acid having a thickness of 125 μm (Nafion (trade name, registered trademark) manufactured by DuPont, USA) is used, and a platinum-ruthenium catalyst ( A paste having a platinum / ruthenium loading amount of 50% by weight was printed to form an anode catalyst layer 133 having an area of 180 cm ² and a thickness of 40 μm. On the other main surface, a platinum catalyst having an area of 180 cm ² and a thickness of 20 μm (platinum supported amount is 70% by weight) is used as the cathode catalyst layer 134, and the anode gas diffusion layer and the cathode gas diffusion layer have a thickness. A 235 μm graphite fiber non-woven fabric (carbon fiber paper SIGRACET GDL25BC manufactured by MFC Technology) was used.

  A cell stack (fuel cell) 13 is assembled using 70 membrane electrode assemblies 131 laminated in series, and the temperature of the cell stack (fuel cell) 13 is set to room temperature in the assembled cell stack (fuel cell). From the state, when 2.5 to 3 wt% aqueous methanol solution and air were supplied so that the actual power generation voltage was fixed at 0.3 V, the time until the generated power reached 1200 W was measured. It was 36 hours. The result is shown in FIG.

<< Comparative Example 1 >>
As a comparative example of Example 1, the same fuel cell system 1 as in Example 1 was used, and the actual power generation voltage was fixed to 0.45 V when the fuel cell system 1 was started up, under the same conditions as in Example 1. It was 0.5 hour when the time until the fuel cell system 1 was started and the generated power reached 1200 W was measured. The result is shown in FIG.

<Discussion>
From the result of FIG. 4, in the starting method of the fuel cell system of Comparative Example 1, it takes 0.5 hours to reach the target generated power 1200 W, and the amount of power shortage during this time is 278 Wh. On the other hand, in the starting method of the fuel cell system of Example 1, the target generated power 1200 W is reached in 0.36 hours, and the amount of power shortage during this period is 162 Wh, a 42% decrease compared to Comparative Example 1. I was able to confirm.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 11 ... Fuel supply apparatus 111 ... 1st tank 112 ... 1st flow path 114 ... 2nd flow path 116 ... 3rd flow path 118 ... 4th flow path 121 ... 5th flow path 124 ... 6th flow Path 113 ... first pump 115 ... filter 117 ... blower 119 ... condenser 120 ... third tank 122 ... third pump 123 ... second tank 125 ... second pump 126 ... temperature sensor 12 ... control device 13 ... fuel cell (battery) stack)
131 ... membrane electrode assembly 132 ... polymer electrolyte membrane 133 ... anode catalyst layer 134 ... cathode catalyst layer 135 ... anode separator 135A ... anode supply part 135B ... anode discharge part 136 ... cathode separator 136A ... cathode supply part 136B ... cathode discharge part 14 ... Battery 2 ... Power load

Claims (1)

A battery stack including a membrane electrode assembly;
Fuel supply means for supplying liquid fuel to the anode of the cell stack;
An oxidant supply means for supplying an oxidant to the cathode of the battery stack;
Temperature detecting means for detecting the temperature of the battery stack;
A battery for supplying electric power to the fuel supply means and the oxidant supply means, and a fuel cell system comprising:
When the temperature of the battery stack is lower than a predetermined temperature at the time of starting the fuel cell system, at least until the temperature of the battery stack reaches the predetermined temperature,
A starting method of a fuel cell system, wherein an actual power generation voltage of the battery stack is controlled to a voltage lower than a rated power generation voltage.

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