JP2008034380A - Fuel cell system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system in which an abnormality of a water solusion supplying means can be judged without providing a new sensor for an abnormality judgement and provide its operation method. <P>SOLUTION: The fuel cell system 100 is provided with a cell stack 102 and a water solution supplying means to supply a methanol water solution to the cell stack 102. The water solution supplying means is composed to make possible a recycling supply of the methanol water solution to the cell stack 102 and includes a main passage to be connected with the cell stack 102, an auxiliary passage to be bifurcated and to be connected with a gas source, a water solution tank 116 to hold the methanol water solution and a water solution pump 136. The auxiliary passage is provided with an ultra-sonic sensor 154. The ultra-sonic sensor 154 is provided on a higher position than a liquid surface of the water solution tank 116 when the water solution pump 136 is not in operation. Based on a detection result of a concentration information from the ultra-sonic sensor 154, an abnormality of the water solution supplying means is judged. Furthermore, a detection result of a liquid volume inside the water soltion tank 116 can be taken into consideration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system and an operation method thereof, and more particularly to a fuel cell system having a protection function and an operation method thereof.

  In the fuel cell system, the aqueous fuel solution is supplied to the anode of the fuel cell by the aqueous solution pump, and the air containing oxygen is supplied to the cathode of the fuel cell by the air pump. The aqueous solution pump is driven by transmitting the rotational power of a motor driven by electric energy to the pump body via a rotating shaft. Here, when the rotating shaft breaks and the power of the motor is not transmitted to the pump body, the supply of the aqueous fuel solution stops, or the supply amount of the aqueous fuel solution decreases when the motor performance deteriorates due to deterioration of the motor. Is assumed.

  When such an abnormality occurs, fuel is unevenly distributed in the anode and the electrolyte membrane is deteriorated. Further, when the supply amount of the aqueous fuel solution decreases, there arises a problem that the output of the fuel cell decreases.

  Also, an abnormality such as a broken pipe as a flow path of the aqueous fuel solution or an abnormality such as a hole in the pipe is assumed. When such an abnormality occurs, the supply of the aqueous fuel solution stops or decreases, thereby causing the same problem as when the pump is abnormal.

It is conceivable to determine the abnormality based on the detection result of a flow sensor or a pressure sensor arranged in the flow path of the aqueous fuel solution. Patent Document 1 discloses a fuel cell system that detects an abnormality of a fuel cell cooling system based on a refrigerant flow rate and a refrigerant pressure.
JP 2002-184435 A

  However, if the technique disclosed in Patent Document 1 is used to determine abnormality of the aqueous solution supply means, a sensor for detecting a flow rate and a sensor for detecting pressure must be newly provided.

  SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a fuel cell system and its operating method capable of determining an abnormality of an aqueous solution supply means without providing a new sensor for determining an abnormality.

  In order to achieve the above object, the fuel cell, the aqueous solution supply means for supplying the aqueous fuel solution to the fuel cell, and the aqueous solution supply means are provided to detect the concentration information of the aqueous fuel solution based on the physical characteristics of the aqueous fuel solution. A fuel cell system is provided that includes a concentration detection unit and a determination unit that determines an abnormality of the aqueous solution supply unit based on a detection result of the concentration detection unit.

  A method for operating a fuel cell system comprising a fuel cell and an aqueous solution supply means for supplying an aqueous fuel solution to the fuel cell, wherein the concentration detection detects concentration information of the aqueous fuel solution based on physical characteristics of the aqueous fuel solution There is provided a method for operating a fuel cell system, comprising a determination step for determining an abnormality of the aqueous solution supply means based on the detection result in the step and the concentration detection step.

  In the above-described invention, when an abnormality occurs in the aqueous solution supply unit, for example, the flow path, air is mixed into the aqueous fuel solution from the outside, and gas is introduced into the concentration detection unit, the physical characteristics of the aqueous fuel solution are used. The density information cannot be detected. By utilizing this phenomenon, the abnormality of the aqueous solution supply means can be determined based on the detection result of the concentration information. In particular, an abnormality upstream of the concentration detection means (concentration detection location) in the aqueous solution supply means can be suitably detected. Further, since the detection result of the fuel concentration is used in this way, it is possible to determine the abnormality of the aqueous solution supply means without providing a new sensor for detecting the abnormality.

  Preferably, the aqueous solution supply means includes an aqueous solution pump, and the concentration detection means is provided in the aqueous solution supply means at a position where gas is present when the aqueous solution pump is stopped. In this case, if the aqueous solution pump stops due to an abnormality, the aqueous fuel solution cannot be supplied to the concentration detection means, or the supply amount decreases, and gas is introduced into the concentration detection means. As a result, it becomes impossible to detect the concentration information using the physical characteristics of the aqueous fuel solution. By utilizing this phenomenon, the abnormality of the aqueous solution supply means can be determined based on the detection result of the concentration information. In particular, an abnormality of the aqueous solution pump can be detected suitably.

  Preferably, the aqueous solution supply means includes an aqueous solution holding means for holding an aqueous fuel solution to be supplied to the fuel cell, a main flow path connected to the fuel cell, and a sub flow path branched from the main flow path and connected to a gas source, The detection means is provided at a position higher than the liquid level of the aqueous solution holding means when the aqueous solution pump is stopped. In this case, when the aqueous solution pump stops due to an abnormality, the gas from the gas source is introduced into the main channel via the sub-channel, and the liquid level of the main channel is lowered to the level of the aqueous solution holding means. Thereby, gas is introduced into the concentration detection means, and abnormality of the aqueous solution pump can be easily detected.

  More preferably, the concentration detection means is provided in the sub-flow channel. In this case, the concentration information can be detected by flowing the aqueous fuel solution into the sub-flow channel in a state where the flow rate of the aqueous fuel solution is reduced or by stopping the aqueous fuel solution. As a result, it is possible to accurately detect an abnormality of the aqueous solution pump without stopping the supply of the aqueous fuel solution to the fuel cell.

  Preferably, the fuel cell system further includes inflow control means for controlling inflow of the aqueous fuel solution into the sub-flow path. In this case, it is possible to easily control the amount of the aqueous fuel solution flowing from the main channel into the sub channel. For this reason, it is possible to smoothly detect an abnormality of the aqueous solution pump in the sub-channel while smoothly supplying the aqueous fuel solution in the main channel to the fuel cell.

  Preferably, the gas source is a gas layer of the aqueous solution holding means. In this case, a gas source can be easily obtained simply by connecting the sub-flow channel to the gas layer of the aqueous solution holding means.

  More preferably, the aqueous solution supply means includes an aqueous solution holding means for holding an aqueous fuel solution to be supplied to the fuel cell, and is configured to be able to circulate and supply the aqueous fuel solution to the fuel cell. The present invention is suitably used for a fuel cell system capable of circulatingly supplying an aqueous fuel solution to the fuel cell in this way.

  In the case where the aqueous solution supply unit is configured to be able to circulate and supply the aqueous fuel solution as described above, “upstream of the concentration detection unit” means from the concentration detection unit to the anode outlet of the fuel cell via the aqueous solution holding unit. Say.

  Preferably, the apparatus further comprises a liquid amount detection means for detecting the liquid amount in the aqueous solution holding means, and the determination means determines an abnormality of the aqueous solution supply means based on the detection result of the concentration detection means and the detection result of the liquid amount detection means. To do. In this way, the abnormality of the aqueous solution supply means can be more accurately determined by taking into account the liquid amount detection result of the aqueous solution holding means. In particular, an abnormality between the aqueous solution holding means and the concentration detection means (concentration detection location) can be suitably detected.

  Preferably, the concentration detection means is an ultrasonic sensor including a transmission unit that transmits ultrasonic waves and a reception unit that receives ultrasonic waves. In this case, the concentration information of the aqueous fuel solution is detected based on the propagation time (propagation speed) of the ultrasonic wave obtained by receiving the ultrasonic wave from the transmission unit at the reception unit. However, if an abnormality occurs in the aqueous solution supply means, gas is introduced between the transmitter and the receiver, and concentration information cannot be detected. Therefore, the abnormality of the aqueous solution supply means can be easily and reliably determined by using the ultrasonic sensor.

  Preferably, air supply means for supplying air containing oxygen to the fuel cell, and air supply control means for controlling the operation of the air supply means based on the determination result of the determination means are further provided. If air is supplied in a state where the aqueous solution supplying means is abnormal and the aqueous fuel solution is not supplied or the supply amount is reduced, the aqueous fuel solution is insufficient in a part of the fuel cell, and the power generation reaction of the fuel cell is biased. This causes deterioration of the electrolyte membrane. For this reason, when it is determined that the aqueous solution supply means is abnormal, the deterioration of the electrolyte membrane can be prevented by stopping the air supply means. In addition, when the air supply unit is controlled to be driven after confirming that there is no abnormality in the aqueous solution supply unit based on the detection result of the concentration information at the time of start-up, the deterioration of the electrolyte membrane can be surely prevented. .

  Preferably, the information processing apparatus further includes notification means for notifying the determination result of the determination means. By notifying the abnormality of the aqueous solution supply means, the convenience of the fuel cell system is improved.

  When the fuel cell system is mounted on transportation equipment, it is desirable to reduce the number of components and the system. In this invention, it is possible to determine the abnormality of the aqueous solution supply means without providing a new sensor for abnormality determination, and it is possible to configure the system small without increasing the number of components. For this reason, this invention is used suitably for transportation equipment.

  According to the present invention, by using the detection result of the concentration information of the aqueous fuel solution, it is possible to determine the abnormality of the aqueous solution supply means without providing a new sensor for determining the abnormality.

Embodiments of the present invention will be described below with reference to the drawings. Here, a case where the fuel cell system 100 of the present invention is mounted on a motorcycle 10 which is an example of a transportation device will be described.
First, the motorcycle 10 will be described. Left and right, front and rear, and top and bottom in the embodiment of the present invention mean left and right, front and back, and top and bottom, based on the state where the driver is seated on the seat of the motorcycle 10 toward the handle 24 thereof.

  Referring to FIG. 1, a motorcycle 10 has a body frame 12. The vehicle body frame 12 includes a head pipe 14, a front frame 16 having an I-shaped longitudinal section extending obliquely downward from the head pipe 14, a rear frame 18 connected to a rear end portion of the front frame 16 and rising obliquely upward rearward, And a seat rail 20 attached to the upper end of the rear frame 18.

  The front frame 16 has a plate-like member 16a having a width in the vertical direction and extending obliquely downward to the rear and orthogonal to the left-right direction, and is formed at the upper and lower edges of the plate-like member 16a, respectively, and in the left-right direction. Are provided with flange portions 16b and 16c having a width and extending rearward and obliquely downward, and reinforcing ribs 16d projecting on both surfaces of the plate-like member 16a. The reinforcing rib 16d partitions both surfaces of the plate-like member 16a together with the flange portions 16b and 16c, and forms a storage space for storing components of the fuel cell system 100 described later.

  On the other hand, the rear frame 18 includes a pair of plate-like members each having a width in the front-rear direction, extending obliquely upward to the rear, and arranged on the left and right sides so as to sandwich the rear end portion of the front frame 16. In FIG. 1, the left plate member of the rear frame 18 is shown.

  A steering shaft 22 for changing the vehicle body direction is rotatably inserted into the head pipe 14. A handle support portion 26 to which a handle 24 is fixed is attached to the upper end of the steering shaft 22. A display operation unit 28 is disposed at the upper end of the handle support unit 26.

  Referring also to FIG. 3, the display operation unit 28 is a meter 28 a for measuring and displaying various data of an electric motor 44 (described later) for driving the motorcycle 10, for example, a liquid crystal display for providing various information such as a running state And the like, and an input unit 28c for inputting various instructions and various information are integrally provided. The input unit 28c has a start button 30a for connecting an external load such as the electric motor 44 and the cell stack 102 and a secondary battery 126 (described later) by switching the relay 176, and the power generation of the cell stack 102 after an operation stop instruction. A stop button 30b for instructing the stop and a backlight 30c for lighting the stop button 30b are provided.

  As shown in FIG. 1, a pair of left and right front forks 32 are attached to the lower end of the steering shaft 22, and a front wheel 34 is attached to the lower end of each front fork 32 via a front axle 36. . The front wheel 34 is rotatably supported by a front axle 36 while being buffered and suspended by a front fork 32.

  On the other hand, a frame-like seat rail 20 extending in the front-rear direction is fixed to the upper end portion of the rear frame 18 by, for example, welding. A seat (not shown) is provided on the seat rail 20 so as to be freely opened and closed.

  A swing arm (rear arm) 38 is swingably supported on the lower end portion of the rear frame 18 via a pivot shaft 40. A rear end portion 38a of the swing arm 38 incorporates, for example, an axial gap type electric motor 44 that is connected to the rear wheel 42 and drives the rear wheel 42 to rotate. Further, the swing arm 38 includes a drive unit 46 that is electrically connected to the electric motor 44. The drive unit 46 includes a controller 48 for controlling the rotational drive of the electric motor 44 and a storage amount detector 50 for detecting the storage amount of the secondary battery 126. The swing arm 38 and the rear wheel 42 are buffered and suspended with respect to the rear frame 18 by a rear cushion (not shown).

  In such a motorcycle 10, components of the fuel cell system 100 are arranged along the body frame 12. The fuel cell system 100 generates electric energy for driving the electric motor 44 and auxiliary machines.

Hereinafter, the fuel cell system 100 will be described with reference to FIGS. 1 and 2.
The fuel cell system 100 is a direct methanol fuel cell system that directly uses methanol (aqueous methanol solution) for generation (electric power generation) of electric energy without reforming.

  The fuel cell system 100 includes a fuel cell stack (hereinafter simply referred to as a cell stack) 102. As shown in FIG. 1, the cell stack 102 is suspended from the flange portion 16 c and disposed below the front frame 16.

  As shown in FIG. 2, the cell stack 102 is formed by stacking a plurality of fuel cells (fuel cell) 104 that can generate electricity by an electrochemical reaction between hydrogen ions based on methanol and oxygen. It is configured. Each fuel cell 104 constituting the cell stack 102 includes an electrolyte membrane 104a made of a solid polymer membrane or the like, and an anode (fuel electrode) 104b and a cathode (air electrode) 104c facing each other across the electrolyte membrane 104a. Including. Each of the anode 104b and the cathode 104c includes a platinum catalyst layer provided on the electrolyte membrane 104a side.

  Further, as shown in FIG. 1, a radiator unit 108 is disposed below the front frame 16 and above the cell stack 102. The front surface of the radiator unit 108 is disposed downward, and can sufficiently receive wind during traveling.

  As shown in FIG. 2, the radiator unit 108 is a unit in which an aqueous solution radiator 108 a and a gas-liquid separation radiator 108 b are integrally provided. On the back side of the radiator unit 108, a fan 110 for cooling the radiator 108a and a fan 112 (see FIG. 3) for cooling the radiator 108b are provided. In FIG. 1, it is assumed that the radiators 108a and 108b are arranged on the left and right, and a fan 110 for cooling the left radiator 108a is shown.

  Further, a fuel tank 114, an aqueous solution tank 116, and a water tank 118 are disposed between the pair of plate-like members of the rear frame 18 in order from above.

  The fuel tank 114 is disposed on the lower side of the seat rail 20 and is attached to the rear end portion of the seat rail 20. The fuel tank 114 accommodates a methanol fuel (high concentration aqueous methanol solution) with a high concentration (for example, containing about 50 wt% of methanol) that serves as a fuel for the electrochemical reaction of the cell stack 102. A level sensor 120 is attached to the fuel tank 114 to detect the height of the liquid level of the methanol fuel in the fuel tank 114 and the liquid amount.

  The aqueous solution tank 116 is disposed below the fuel tank 114 and attached to the rear frame 18. The aqueous solution tank 116 contains an aqueous methanol solution obtained by diluting the methanol fuel from the fuel tank 114 to a concentration suitable for the electrochemical reaction of the cell stack 102 (for example, containing about 3 wt% of methanol). A level sensor 122 is attached to the aqueous solution tank 116 to detect the height of the liquid surface of the aqueous methanol solution in the aqueous solution tank 116 and the amount of liquid.

  The water tank 118 is disposed on the rear side of the cell stack 102 and is attached to the rear frame 18. A level sensor 124 is attached to the water tank 118 to detect the height of the water surface in the water tank 118 and the amount of water.

  Further, a secondary battery 126 is disposed on the front side of the fuel tank 114 and on the upper side of the flange portion 16 b of the front frame 16. The secondary battery 126 stores electric power from the cell stack 102 and supplies electric power to an electric component in accordance with a command from a controller 142 (described later).

  A fuel pump 128 is disposed above the secondary battery 126 and below the seat rail 20. In addition, a catch tank 130 is disposed on the front side of the fuel tank 114 and on the diagonally upper side of the secondary battery 126.

  In a space surrounded by the front frame 16, the cell stack 102, and the radiator unit 108, an air filter 132 for removing foreign matters such as dust contained in the gas is disposed. An aqueous solution filter 134 is disposed.

  In the storage space on the left side of the front frame 16, an aqueous solution pump 136 and an air pump 138 are stored. An air chamber 140 is disposed on the left side of the air pump 138.

  In the storage space on the right side of the front frame 16, a controller 142, a rust prevention valve 144, and a water pump 146 are arranged.

  The front frame 16 is provided with a main switch 148 so as to penetrate the storage space of the front frame 16 from the right side to the left side. When the main switch 148 is turned on, an operation start instruction is given to the controller 142, and when the main switch 148 is turned off, an operation stop instruction is given to the controller 142.

  As shown in FIG. 2, the fuel tank 114 and the fuel pump 128 are communicated by a pipe P1, the fuel pump 128 and the aqueous solution tank 116 are communicated by a pipe P2, and the aqueous solution tank 116 and the aqueous solution pump 136 are communicated by a pipe P3. The aqueous solution pump 136 and the aqueous solution filter 134 are communicated with each other by a pipe P4, and the aqueous solution filter 134 and the cell stack 102 are communicated with each other by a pipe P5. The pipe P5 is connected to the anode inlet I1 of the cell stack 102, and an aqueous methanol solution is supplied to the cell stack 102 by driving the aqueous solution pump 136. Near the anode inlet I1 of the cell stack 102, a temperature sensor 150 for detecting the temperature of the aqueous methanol solution is provided. When the temperature sensor 150 detects the temperature of the aqueous methanol solution flowing in the cell stack 102, the temperature of the cell stack 102 can be detected.

The cell stack 102 and the aqueous solution radiator 108a are connected with each other by a pipe P6, and the radiator 108a and the aqueous solution tank 116 are connected with each other by a pipe P7. The pipe P6 is connected to the anode outlet I2 of the cell stack 102.
The pipes P1 to P7 described above mainly serve as fuel flow paths.

  Further, the air filter 132 and the air chamber 140 are communicated by a pipe P8, the air chamber 140 and the air pump 138 are communicated by a pipe P9, and the air pump 138 and the rust prevention valve 144 are communicated by a pipe P10 and are used for rust prevention. The valve 144 and the cell stack 102 are communicated with each other by a pipe P11. The pipe P11 is connected to the cathode inlet I3 of the cell stack 102. When the fuel cell system 100 generates power, the rust prevention valve 144 is opened, and the air pump 138 is driven in this state, whereby oxygen-containing air is sucked from the outside. The rust prevention valve 144 is closed when the fuel cell system 100 is stopped, and prevents the backflow of water vapor to the air pump 138 and prevents the air pump 138 from rusting. In the vicinity of the air filter 132, an outside air temperature sensor 152 that detects the outside air temperature is provided.

The cell stack 102 and the gas-liquid separating radiator 108b are communicated by a pipe P12, the radiator 108b and the water tank 118 are communicated by a pipe P13, and the water tank 118 is provided with a pipe (exhaust pipe) P14.
The pipes P8 to P14 described above mainly serve as an oxidant flow path.

Further, the water tank 118 and the water pump 146 are communicated by a pipe P15, and the water pump 146 and the aqueous solution tank 116 are communicated by a pipe P16.
The pipes P15 and P16 described above serve as a water flow path.

  Further, a pipe P17 is connected to the branch part A of the pipe P4 so that a part of the methanol aqueous solution flowing through the pipe P4 flows. An ultrasonic sensor 154 is attached to the pipe P17. The ultrasonic sensor 154 is used to detect the methanol concentration of the aqueous methanol solution (ratio of methanol in the aqueous methanol solution) using the fact that the propagation time (propagation speed) of the ultrasonic wave changes according to the methanol concentration. The ultrasonic sensor 154 includes a transmission unit 154a and a reception unit 154b. The ultrasonic wave transmitted from the transmission unit 154a is received by the reception unit 154b, and the ultrasonic propagation time in the pipe P17 is detected. The corresponding voltage value is used as physical concentration information. The controller 142 detects the methanol concentration of the aqueous methanol solution in the pipe P17 based on the concentration information. The ultrasonic sensor 154 is provided at a position where gas is introduced into the ultrasonic sensor 154 when the aqueous solution supply means is abnormal. In other words, the ultrasonic sensor 154 is provided at a position higher than the liquid level when the aqueous solution supply unit is abnormal. In the example shown in FIG. 2, for example, when the aqueous solution pump 136 is stopped during normal operation and the detection valve 156 is opened for concentration measurement, the gas in the aqueous solution tank 116 is introduced into the pipes P17 and P4 via the pipe P18. The As a result, the liquid level of the main flow path (pipe P3 to P5) is lowered to the liquid level of the aqueous solution tank 116. At this time, the ultrasonic sensor 154 is at a position higher than the liquid level of the main flow path and hence the liquid level of the aqueous solution tank 116, and gas exists in the ultrasonic sensor 154.

A detection valve 156 is connected to the pipe P17, and the detection valve 156 and the gas layer 116a of the aqueous solution tank 116 are communicated with each other by a pipe P18. When detecting the methanol concentration, the detection valve 156 is closed, and the flow of the aqueous methanol solution in the pipe P17 is stopped. After the measurement of the methanol concentration, the detection valve 156 is opened, and the methanol aqueous solution whose concentration has been detected is returned to the aqueous solution tank 116.
The pipes P17 and P18 described above mainly serve as a concentration detection flow path.

Further, the aqueous solution tank 116 and the catch tank 130 are communicated by pipes P19 and P20, and the catch tank 130 and the air chamber 140 are communicated by a pipe P21.
The pipes P19 to P21 described above mainly serve as fuel processing flow paths.

Next, the electrical configuration of the fuel cell system 100 will be described with reference to FIG.
The controller 142 of the fuel cell system 100 performs necessary calculations to control the operation of the fuel cell system 100, a clock circuit 160 that gives a clock to the CPU 158, a program and data for controlling the operation of the fuel cell system 100 And a memory 162 made of, for example, an EEPROM for storing operation data, a voltage detection circuit 166 for detecting a voltage in the electric circuit 164 for connecting the cell stack 102 to an external load, the fuel cell 104 and the cell stack 102 Current detection circuit 168 for detecting the current flowing through the circuit, ON / OFF circuit 170 for opening and closing the electric circuit 164, a diode 172 provided in the electric circuit 164, and a power source for supplying a predetermined voltage to the electric circuit 164 Circuit 174 No.

  Detection signals from the level sensors 120, 122, and 124 and detection signals from the temperature sensor 150, the outside air temperature sensor 152, and the ultrasonic sensor 154 are input to the CPU 158 of the controller 142. The CPU 158 receives an input signal from the main switch 148 for turning on / off the power and an input signal from the start button 30a and the stop button 30b of the input unit 28c. Further, the detection signal from the charged amount detector 50 is input to the CPU 158. The CPU 158 calculates the storage rate of the secondary battery 126 (the ratio of the stored amount to the capacity of the secondary battery 126) using the detection signal from the stored amount detector 50 and the information related to the capacity of the secondary battery 126. Further, the voltage detection value from the voltage detection circuit 166 and the current detection value from the current detection circuit 168 are input to the CPU 158. The CPU 158 calculates the output of the cell stack 102 using the voltage detection value and the current detection value.

  The CPU 158 controls auxiliary equipment such as the fuel pump 128, the aqueous solution pump 136, the air pump 138, the water pump 146, the fans 110 and 112, the antirust valve 144, and the detection valve 156. Further, the CPU 158 controls the display unit 28b for displaying various information and informing the driver of the motorcycle 10 of various information. Further, the CPU 158 controls turning on / off of the backlight 30c of the input unit 28c.

  A secondary battery 126 and a drive unit 46 are connected to the cell stack 102. The secondary battery 126 and the drive unit 46 are connected to an external load such as the electric motor 44 via the relay 176. The secondary battery 126 complements the output from the cell stack 102, is charged by the electric power from the cell stack 102, and supplies electric power to the electric motor 44, the drive unit 46, and auxiliary machines by the discharge.

  A meter 28 a for measuring various data of the electric motor 44 is connected to the electric motor 44, and the data measured by the meter 28 a and the state of the electric motor 44 are given to the CPU 158 via the interface circuit 178.

  In addition, a charger 200 can be connected to the interface circuit 178, and the charger 200 can be connected to an external power source (commercial power source) 202. When the external power supply 202 is connected to the interface circuit 178 via the charger 200, an external power supply connection signal is given to the CPU 158 via the interface circuit 178. The switch 200a of the charger 200 can be turned on / off by the CPU 158.

  The memory 162 stores a program for executing the operations shown in FIGS. Further, the memory 162 stores the number of NG times, a predetermined number of times serving as a threshold of the number of NG times, a liquid amount recovery processing flag, first predetermined time and second predetermined time serving as a threshold, calculation data, and ultrasonic waves as shown in FIG. Table data indicating the correspondence between the propagation time (concentration information), liquid temperature, and fuel concentration is stored.

  FIG. 4 shows only the correspondence relationship (curve) between the propagation time and the liquid temperature at four concentrations (0 wt%, 1.9 wt%, 2.9 wt% and 4.6 wt%). Table data corresponding to five or more curves is used so that the fuel concentration corresponding to the propagation time and the liquid temperature can be determined.

  That is, when the concentration information and the liquid temperature are obtained, the CPU 158 detects the concentration of the aqueous methanol solution with reference to the table data.

  In this embodiment, the aqueous solution supply means includes pipes P3 to P7, P17 and P18, an aqueous solution tank 116, an aqueous solution pump 136, an aqueous solution filter 134, and an aqueous solution radiator 108a, and is configured to be able to circulate and supply an aqueous methanol solution to the cell stack 102. Is done. The aqueous solution tank 116 corresponds to the aqueous solution holding means. The ultrasonic sensor 154 corresponds to a concentration detection unit. The level sensor 122 corresponds to the liquid amount detection means. Pipes P3 to P5 correspond to the main flow path, and pipes P17 and P18 correspond to the sub flow path. The detection valve 156 and the CPU 158 correspond to the inflow control means. The air supply means includes an air pump 138. The CPU 158 corresponds to determination means and air supply control means. The gas layer 116a of the aqueous solution tank 116 corresponds to a gas source. The display unit 28b corresponds to notification means.

Next, main operations during operation of the fuel cell system 100 will be described.
The fuel cell system 100 starts the operation by starting the controller 142 when the main switch 148 is turned on. Then, when the start button 30 a is pressed after the controller 142 is activated, the relay 176 is switched, and an external load such as the electric motor 44 is connected to the cell stack 102 and the secondary battery 126. Further, when the storage rate of the secondary battery 126 becomes equal to or lower than a predetermined value, auxiliary equipment such as the aqueous solution pump 136 and the air pump 138 is driven by the electric power from the secondary battery 126, and the power generation of the cell stack 102 is started.

  The external load refers to a load that consumes electric power excluding electric power necessary for maintaining the power generation of the cell stack 102. Specifically, in this embodiment, the electric motor 44, the headlight of the motorcycle 10, and the like are listed as external loads.

  Referring to FIG. 2, the aqueous methanol solution in aqueous solution tank 116 is supplied to aqueous solution filter 134 via pipes P3 and P4 by driving aqueous solution pump 136. The methanol aqueous solution from which impurities and the like have been removed by the aqueous solution filter 134 is directly supplied to the anode 104b of each fuel cell 104 constituting the cell stack 102 via the pipe P5 and the anode inlet I1.

  Further, the gas (mainly carbon dioxide, vaporized methanol and water vapor) in the aqueous solution tank 116 is given to the catch tank 130 via the pipe P19. In the catch tank 130, the vaporized methanol and water vapor are cooled. Then, the aqueous methanol solution obtained in the catch tank 130 is returned to the aqueous solution tank 116 through the pipe P20. Further, the gas (carbon dioxide, unliquefied methanol and water vapor) in the catch tank 130 is given to the air chamber 140 through the pipe P21.

  On the other hand, air (air) sucked from the air filter 132 by driving the air pump 138 is silenced by flowing into the air chamber 140 through the pipe P8. The air supplied to the air chamber 140 and the gas from the catch tank 130 flow into the air pump 138 through the pipe P9, and further through the pipe P10, the rust prevention valve 144, the pipe P11, and the cathode inlet I3. This is supplied to the cathode 104 c of each fuel cell 104 constituting the cell stack 102.

  In the anode 104b of each fuel cell 104, methanol and water in the supplied aqueous methanol solution chemically react to generate carbon dioxide and hydrogen ions. The generated hydrogen ions flow into the cathode 104c through the electrolyte membrane 104a, and electrochemically react with oxygen in the air supplied to the cathode 104c side to generate water (water vapor) and electric energy. That is, power generation is performed in the cell stack 102. The electric power from the cell stack 102 is used for charging the secondary battery 126, driving the motorcycle 10, and the like. The cell stack 102 rises in temperature due to heat generated by the electrochemical reaction. The output of the cell stack 102 increases as the temperature rises, and the cell stack 102 can generate power constantly at about 60 ° C. That is, the fuel cell system 100 shifts to steady operation when the temperature of the cell stack 102 is about 60 ° C.

  The carbon dioxide and unreacted methanol aqueous solution generated at the anode 104b of each fuel cell 104 are heated by the heat generated by the electrochemical reaction (for example, about 65 ° C. to 70 ° C.), and the unreacted methanol aqueous solution Part of it is vaporized. The carbon dioxide and the unreacted methanol aqueous solution are supplied to the aqueous solution radiator 108a via the anode outlet I2 and the pipe P6 of the cell stack 102, and cooled by the radiator 108a (for example, about 40 ° C.). The cooling operation of carbon dioxide and unreacted methanol by the radiator 108 a is performed by operating the fan 110. The cooled carbon dioxide and the unreacted methanol aqueous solution are returned to the aqueous solution tank 116 through the pipe P7.

  On the other hand, most of the water vapor generated at the cathode 104c of each fuel cell 104 is liquefied and becomes water, and is discharged from the cathode outlet I4 of the cell stack 102, but the saturated water vapor is discharged in a gas state. A part of the water vapor discharged from the cathode outlet I4 is supplied to the radiator 108b through the pipe P12, and is cooled by the radiator 108b to be liquefied by being below the dew point. The water vapor liquefaction operation by the radiator 108b is performed by operating the fan 112. Exhaust gas from the cathode outlet I4 containing moisture (water and water vapor), carbon dioxide and unreacted air is supplied to the water tank 118 through the pipe P12, the radiator 108b and the pipe P13, and water is collected in the water tank 118. After that, it is discharged to the outside through the pipe P14.

  Further, in the cathode 104c of each fuel cell 104, the vaporized methanol from the catch tank 130 and the methanol moved to the cathode 104c due to crossover react with oxygen in the platinum catalyst layer to be decomposed into harmless moisture and carbon dioxide. . Moisture and carbon dioxide decomposed from methanol are discharged from the cathode outlet I4 and supplied to the water tank 118 via the radiator 108b. Further, the water moved to the cathode 104c of each fuel cell 104 due to the water crossover is discharged from the cathode outlet I4 and supplied to the water tank 118 via the radiator 108b. The water collected in the water tank 118 is appropriately returned to the aqueous solution tank 116 via the pipes P15 and P16 by driving the water pump 146, and used as water of the methanol aqueous solution.

  In addition, in the fuel cell system 100 during power generation, a concentration detection process for an aqueous methanol solution is periodically executed in order to cause each fuel cell 104 to generate power efficiently while preventing deterioration of each fuel cell 104. Based on the detection result, the methanol concentration of the aqueous methanol solution in the aqueous solution tank 116 to be supplied to the cell stack 102 is adjusted to about 3 wt%, for example. Specifically, the fuel pump 128 is driven based on the detection result of the methanol concentration, and the methanol fuel in the fuel tank 114 is supplied to the aqueous solution tank 116 via the pipes P1 and P2. Further, the water pump 146 is driven based on the detection result of the methanol concentration, and the water in the water tank 118 is returned to the aqueous solution tank 116.

Next, the abnormality determination operation of the aqueous solution supply unit in the fuel cell system 100 will be described with reference to FIG.
This operation is performed during power generation of the fuel cell system 100.

  First, the detection valve 156 is opened based on an instruction from the CPU 158 (step S1), and a predetermined time (in this embodiment, for example, 3 seconds is sufficient as a time during which the aqueous methanol solution is sufficiently supplied to the ultrasonic sensor 154). Is determined (step S3). The process waits until a predetermined time elapses, and when the predetermined time elapses, the detection valve 156 is closed (step S5). In this manner, the aqueous methanol solution is introduced into the ultrasonic sensor 154, or the aqueous methanol solution in the ultrasonic sensor 154 is replaced.

  Then, the propagation time until the ultrasonic wave from the transmitting unit 154a propagates to the receiving unit 154b, that is, the concentration information of the methanol aqueous solution is detected by the ultrasonic sensor 154 (step S7). Based on the detection result, it is determined whether or not the concentration information of the aqueous methanol solution has been detected, that is, whether or not the ultrasonic wave has been propagated from the transmitting unit 154a to the receiving unit 154b (step S9).

  If the concentration information of the aqueous methanol solution cannot be detected, it is determined that gas is introduced between the transmitter 154a and the receiver 154b, and that there is an abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means. That is, between the branching part A and the receiving part 154b in the pipe P17, upstream of the branching part A in the pipe P4, any of the aqueous solution pump 136, the pipe P3, the aqueous solution tank 116, the pipe P7, the aqueous solution radiator 108a, and the pipe P6 As a result, it is determined that the aqueous methanol solution cannot be supplied normally.

  If the density information cannot be detected in step S9, the NG count indicating the number of times the density information cannot be detected is incremented and stored in the memory 162 (step S11). Then, it is determined whether or not the number of NG times exceeds a predetermined number (for example, 10 times) (step S13). If the NG count does not exceed the predetermined count, the process returns to step S1. As described above, even when it is determined in step S9 that the concentration information cannot be detected, it is not determined that the aqueous solution supply unit is abnormal if the number of NG times is one. The processes in steps S1 to S11 are repeated until the number of NG times reaches a predetermined number.

  In this embodiment, if the predetermined time in step S3 is 3 seconds and the predetermined number of times in step S13 is 10, the step S13 is YES when the density information cannot be detected continuously for 30 (= 3 × 10) seconds or more. become.

  Here, even after the aqueous solution pump 136 is stopped and the fuel supply to the cell stack 102 is cut off, it is possible to generate power for about 1 minute using only the fuel in the cell stack 102. In other words, the electrolyte membrane 104a may be damaged if it exceeds 1 minute after the fuel supply is stopped. Therefore, if the predetermined number of times in step S13 is set to 10 and the time for determining that there is an abnormality is set to be within 1 minute, it is possible to detect whether or not an abnormality has occurred without damaging the electrolyte membrane 104a.

  If the number of NG times exceeds the predetermined number in step S13, the CPU 158 determines that there is an abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means including the aqueous solution pump 136 and the like, and the determination result is displayed on the display unit 28b. (Step S15). Then, error processing including stopping of the air pump 138 and the like is performed (step S17), the stored NG count is cleared (step S19), and the process is terminated.

  On the other hand, if the concentration information can be detected in step S9, it is determined that there is no abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means, the stored NG count is cleared (step S19), and the process ends.

  According to the fuel cell system 100 operating in this way, if an abnormality occurs in the aqueous solution supply means, for example, the rotating shaft of the aqueous solution pump 136 is broken and the aqueous methanol solution cannot be supplied, the aqueous methanol solution cannot be supplied to the ultrasonic sensor 154 or The supply amount decreases and gas is introduced into the ultrasonic sensor 154. As a result, it becomes impossible to detect the concentration information using the physical characteristics of the methanol aqueous solution. By utilizing this phenomenon, it is possible to determine (detect) an abnormality upstream of the ultrasonic sensor 154 (concentration detection location) in the aqueous solution supply means based on the detection result of the concentration information. Further, since the detection result of the fuel concentration is used in this way, it is possible to determine the abnormality of the aqueous solution supply means without providing a new sensor for determining the abnormality.

  When the aqueous solution pump 136 is stopped due to an abnormality, the gas from the gas layer 116a of the aqueous solution tank 116, which is a gas source, is introduced into the main flow path via pipes P18, P17, which are sub flow paths. As a result, the liquid level of the main flow path is lowered to the liquid level of the aqueous solution tank 116. Thereby, gas is introduced into the ultrasonic sensor 154 and abnormality of the aqueous solution pump 136 can be easily detected.

  Further, the concentration information can be detected by flowing the methanol aqueous solution into the sub-flow passage composed of the pipes P17 and P18 while the flow rate of the methanol aqueous solution is reduced or the methanol aqueous solution is stopped. As a result, the abnormality of the aqueous solution pump 136 can be accurately detected without stopping the supply of the aqueous methanol solution to the cell stack 102.

  In addition, since the amount of aqueous methanol solution flowing from the main channel into the sub-channel can be easily controlled using the detection valve 156, the sub-channel can be supplied while smoothly supplying the methanol aqueous solution in the main channel to the cell stack 102. Thus, the abnormality of the aqueous solution pump 136 can be detected smoothly.

  Furthermore, a gas source can be easily obtained simply by connecting the sub-flow channel to the gas layer 116 a of the aqueous solution tank 116.

  The present invention is suitably used for a fuel cell system that can circulate and supply an aqueous methanol solution to the cell stack 102 as in the fuel cell system 100.

  Furthermore, by using the ultrasonic sensor 154, the abnormality of the aqueous solution supply means can be determined easily and reliably.

  In addition, when the aqueous solution supply unit is determined to be abnormal, the deterioration of the electrolyte membrane 104a can be prevented by stopping the air pump 138. Furthermore, when starting the air pump 138 after confirming that there is no abnormality in the aqueous solution supply means based on the detection result of the concentration information at the time of startup, the deterioration of the electrolyte membrane 104a can be reliably prevented. .

  Furthermore, the convenience of the fuel cell system 100 is improved by notifying the abnormality of the aqueous solution supply means.

  Further, in the present invention, the abnormality of the aqueous solution supply means can be determined without providing a new sensor for abnormality determination, and the fuel cell system 100 can be made smaller without increasing the number of components. Therefore, the present invention is suitable for the motorcycle 10. Used for

  Next, another abnormality determination operation of the fuel cell system 100 will be described with reference to FIGS. 6 and 7. In this example, the operations of FIGS. 6 and 7 are performed in parallel during power generation of the fuel cell system 100.

First, the operation of FIG. 6 will be described.
The amount of liquid in the aqueous solution tank 116 is detected by the level sensor 122 (step S101), and the CPU 158 determines whether or not the amount of liquid in the aqueous solution tank 116 is equal to or greater than a predetermined amount (step S103). If the liquid amount in the aqueous solution tank 116 is less than the predetermined amount, the fuel pump 128 and / or the water pump 146 are driven to perform the liquid amount recovery process (step S105), and the liquid amount recovery process flag is set (step S107). ).

  Here, the liquid amount recovery process is an operation of driving the water pump 146 to return the liquid level of the aqueous solution tank 116 to the standard, and then driving the fuel pump 128 to adjust the concentration to a predetermined range.

  Then, it is determined whether or not a first predetermined time (for example, 20 seconds) has elapsed since the liquid amount recovery processing flag was set (after the flag was switched from 0 to 1) (step S109). If the first predetermined time has not elapsed, the process returns to step S101. On the other hand, when the first predetermined time elapses, the CPU 158 determines that there is an abnormality in the aqueous solution system, that is, the means for supplying fuel and water to the aqueous solution tank 116 such as the fuel pump 128 and the water pump 146, and the determination result is It is notified by being displayed on the display unit 28b (step S111). Then, after the aqueous solution type error processing is performed (step S113), the liquid amount recovery processing flag is cleared (step S115), and the process is terminated.

  On the other hand, if the liquid amount in the aqueous solution tank 116 is equal to or greater than the predetermined amount in step S103, the liquid amount recovery processing flag is cleared (step S115), and the process ends.

Next, the operation of FIG. 7 will be described.
First, the detection valve 156 is opened based on an instruction from the CPU 158 (step S121), and a second predetermined time (in this embodiment, for example, 3 seconds is a time for which the aqueous methanol solution is sufficiently supplied to the ultrasonic sensor 154). It is determined whether or not it has elapsed (step S123). The process waits until a predetermined time elapses, and when the predetermined time elapses, the detection valve 156 is closed (step S125). In this manner, the aqueous methanol solution is introduced into the ultrasonic sensor 154, or the aqueous methanol solution in the ultrasonic sensor 154 is replaced.

Then, the concentration information of the aqueous methanol solution is detected by the ultrasonic sensor 154 (step S127), and whether or not the concentration information of the aqueous methanol solution has been detected, that is, whether or not the ultrasonic wave has been propagated from the transmitting unit 154a to the receiving unit 154b. Judgment is made (step S129).
If the concentration information of the aqueous methanol solution cannot be detected, a gas is introduced between the transmitter 154a and the receiver 154b, and there is an abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means. Is determined to be unable to be supplied normally.

  If the density cannot be detected in step S129, the NG count indicating the number of times that the density information cannot be detected is incremented and stored in the memory 162 (step S131). Then, it is determined whether or not the number of NG times exceeds a predetermined number (for example, 10 times) (step S133). If the NG count does not exceed the predetermined count, the process returns to step S121. Thus, even if it is determined in step S129 that concentration information cannot be detected, it is not determined that the aqueous solution supply unit is abnormal if the number of NG times is one. The processes in steps S121 to S131 are repeated until the number of NG times reaches a predetermined number.

  On the other hand, if the number of NG times exceeds the predetermined number in step S133, it is determined whether or not a liquid amount recovery processing flag is set (step S135). If the liquid amount recovery processing flag is not set, it is determined that there is an abnormality between the aqueous solution supply means upstream of the ultrasonic sensor 154 and up to the aqueous solution tank 116. That is, there is an abnormality in the pipe P17 between the branching part A and the receiving part 154b and in the pipe P4 upstream of the branching part A, either the aqueous solution pump 136 or the pipe P3. As a result, the aqueous methanol solution is normally supplied. It is determined that it is not completed. Then, the determination result is notified by being displayed on the display unit 28b (step S137), error processing including stop of the air pump 138 and the like is performed (step S139), and the stored NG count is cleared (step S141). ),finish.

  If the liquid amount recovery process flag is set in step S135, the stored NG count is cleared (step S143), and the process returns to step S121. When the liquid amount recovery processing flag is set as described above, it is not known whether there is an abnormality between the aqueous solution supply means upstream of the ultrasonic sensor 154 and up to the aqueous solution tank 116. Is cleared and the process returns to step S121.

  On the other hand, if the concentration information can be detected in step S129, it is determined that there is no abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means, the stored NG count is cleared (step S141), and the process ends.

  According to the fuel cell system 100 operating in this way, it is possible to more accurately determine the abnormality of the aqueous solution supply means by taking into consideration the liquid amount detection result of the aqueous solution tank 116. In particular, an abnormality between the aqueous solution tank 116 and the ultrasonic sensor 154 (concentration detection location) can be detected suitably.

  Moreover, the same effect as the case of operating as shown in FIG. 5 can be obtained.

  The detection valve 156 may be provided at the branching portion A to which the pipes P4 and P17 are connected.

  Further, the notification means is not limited to the display unit 28b, and may be notified by sound using a speaker or the like.

  The temperature detection of the aqueous methanol solution is not limited to the case where it is detected by the temperature sensor 150, and a temperature sensor may be provided in the vicinity of the ultrasonic sensor 154 to detect the temperature of the aqueous methanol solution in the pipe P17.

  The position of the ultrasonic sensor 154 is not limited to the pipe P17, and may be provided in any of the pipes P3 to P5. In this case, an abnormality upstream of the ultrasonic sensor 154 in the aqueous solution supply means can be detected. When the ultrasonic sensor 154 is provided on the pipe P3 (upstream side of the aqueous solution pump 136), an abnormality of the aqueous solution pump 136 can be further detected.

  In the above-described embodiment, the ultrasonic sensor 154 is used as the concentration detection unit that detects the concentration of the aqueous methanol solution based on the physical characteristics of the aqueous methanol solution, but is not limited thereto. As the concentration detection means, any sensor that physically detects the concentration based on the refractive index, dielectric constant, infrared absorption rate, viscosity, freezing point, and the like can be used. These sensors are provided at positions where gas is introduced into the sensor when the aqueous solution supply means is abnormal.

  The gas source is not limited to the gas layer 116 a of the aqueous solution tank 116, and may be the outside air of the fuel cell system 100.

  The fuel cell system of the present invention can be suitably used not only for motorcycles but also for any transportation equipment such as automobiles and ships.

  In the above embodiment, methanol is used as the fuel, and methanol aqueous solution is used as the fuel aqueous solution. However, the present invention is not limited to this. Good.

  The present invention can be applied to a reformer-equipped fuel cell system and a stationary fuel cell system as long as liquid fuel is used. Further, the present invention can be applied to personal computers, portable devices, small electronic devices, etc. It can also be applied to a fuel cell system.

  Although the invention has been described and illustrated in detail, it is clear that the invention has been used merely as an illustration and example and should not be construed as limiting, the spirit and scope of the invention being claimed. Limited only by the wording of the scope.

1 is a left side view showing a motorcycle according to an embodiment of the present invention. It is a system diagram which shows piping of a fuel cell system. It is a block diagram which shows the electric constitution of a fuel cell system. It is a graph which shows the relationship between ultrasonic propagation time, liquid temperature, and fuel concentration. It is a flowchart which shows an example of operation | movement of this invention. It is a flowchart which shows the other example of operation | movement of this invention. It is a flowchart which shows the other example of operation | movement of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motorcycle 28b Display part 100 Fuel cell system 102 Fuel cell stack 104 Fuel cell (fuel cell)
108a Aqueous solution radiator 116 Aqueous solution tank 116a Gas layer 120, 122, 124 Level sensor 134 Aqueous solution filter 136 Aqueous solution pump 138 Air pump 142 Controller 154 Ultrasonic sensor 154a Transmitting unit 154b Receiving unit 156 Detection valve 158 CPU
162 Memory P1-P21 Pipe

Claims (13)

Fuel cell,
An aqueous solution supply means for supplying an aqueous fuel solution to the fuel cell;
Concentration detection means provided in the aqueous solution supply means for detecting concentration information of the aqueous fuel solution based on physical characteristics of the aqueous fuel solution, and determining abnormality of the aqueous solution supply means based on a detection result of the concentration detection means A fuel cell system comprising determination means for performing. The aqueous solution supply means includes an aqueous solution pump,
2. The fuel cell system according to claim 1, wherein the concentration detection unit is provided at a position where gas exists when the aqueous solution pump is stopped in the aqueous solution supply unit. The aqueous solution supply means includes an aqueous solution holding means for holding the aqueous fuel solution to be supplied to the fuel cell, a main flow path connected to the fuel cell, and a sub flow path branched from the main flow path and connected to a gas source,
The fuel cell system according to claim 2, wherein the concentration detection means is provided at a position higher than the liquid level of the aqueous solution holding means when the aqueous solution pump is stopped.   The fuel cell system according to claim 3, wherein the concentration detection means is provided in the sub-flow channel.   The fuel cell system according to claim 4, further comprising an inflow control unit that controls inflow of the aqueous fuel solution into the sub-flow channel.   The fuel cell system according to claim 3, wherein the gas source is a gas layer of the aqueous solution holding means.   2. The fuel cell system according to claim 1, wherein the aqueous solution supply unit includes an aqueous solution holding unit that holds an aqueous fuel solution to be supplied to the fuel cell, and is configured to be able to circulate and supply the aqueous fuel solution to the fuel cell. A liquid amount detecting means for detecting the amount of liquid in the aqueous solution holding means;
The fuel cell system according to claim 7, wherein the determination unit determines an abnormality of the aqueous solution supply unit based on a detection result of the concentration detection unit and a detection result of the liquid amount detection unit.   2. The fuel cell system according to claim 1, wherein the concentration detection unit is an ultrasonic sensor including a transmission unit that transmits ultrasonic waves and a reception unit that receives the ultrasonic waves. 2. The fuel cell according to claim 1, further comprising: an air supply unit that supplies air containing oxygen to the fuel cell; and an air supply control unit that controls an operation of the air supply unit based on a determination result of the determination unit. system.   The fuel cell system according to claim 1, further comprising notification means for notifying a determination result of the determination means.   A transportation device comprising the fuel cell system according to claim 1. A method for operating a fuel cell system comprising a fuel cell and an aqueous solution supply means for supplying an aqueous fuel solution to the fuel cell,
A concentration detection step of detecting concentration information of the aqueous fuel solution based on physical characteristics of the aqueous fuel solution, and a determination step of determining abnormality of the aqueous solution supply means based on a detection result in the concentration detection step Battery system operation method.

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