Fuel cell system

Abstract

The invention provides a fuel cell system. In a fuel cell system which is provided with a plurality of fuel cells and a storage battery and does not have a DC-DC converter, deterioration of the plurality of fuel cells is suppressed, and deterioration of durability of the fuel cell system is suppressed. A fuel cell system (1) is provided with three FC stacks (11A-11C) connected in parallel, one battery (12) connected to all of the three FC stacks (11A-11C), and a control device (20), and is not provided with a DC-DC converter. The control device (20) is configured so as to simultaneously measure the FC currents of the three FC stacks (11A-11C). The control device (20) controls the power generation of the three FC stacks (11A-11C) on the basis of the difference between the simultaneously measured FC currents.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a fuel cell system having a fuel cell and a battery into which the electricity generated by the fuel cell is charged. Background Technology

[0002] Previously, for example, a "power generation device" described in Patent Document 1 is known. This device is configured to have multiple fuel cells connected in parallel, a secondary battery (storage battery) connected to all of the multiple fuel cells, a load, and a control device, and is a device without a DC-DC converter. The control device controls the start-up and shutdown of the multiple fuel cells and the storage battery in consideration of the load and the start-up time of the fuel cells.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-294190 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The power generation device described in Patent Document 1 is configured as a device without a DC-DC converter, thus simplifying the structure. However, there are sometimes differences in the degree of degradation among the multiple fuel cells. If the multiple fuel cells are operated without considering the differences in degradation, the durability of the fuel cell with greater degradation will decrease more rapidly, and the durability of the power generation device may be reduced.

[0008] This disclosure is made in view of the above circumstances, and its purpose is to suppress the degradation of multiple fuel cells and the reduction in the durability of the fuel cell system in a fuel cell system having multiple fuel cells and a storage battery but no DC-DC converter.

[0009] Solution for solving the problem

[0010] To achieve the above objectives, the technology described in the first invention is a fuel cell system comprising multiple fuel cells connected in parallel and a storage battery connected to all of the multiple fuel cells, and without a DC-DC converter. The main feature of the fuel cell system is that it also includes a control device for controlling the power generation of the multiple fuel cells. The control device is configured to simultaneously measure the current of the multiple fuel cells and control the power generation of the multiple fuel cells based on the differences in the measured current values ​​of each fuel cell.

[0011] According to the structure of the above technology, the control device simultaneously measures the current of multiple fuel cells and controls the power generation of the multiple fuel cells based on the differences in the measured current values ​​of each fuel cell. Therefore, it is possible to use fuel cells with high measured current values ​​and less degradation for power generation, while suppressing the use of fuel cells with low measured current values ​​and a risk of degradation for power generation. Thus, it is possible to suppress the individual degradation of multiple fuel cells and to suppress the decrease in the durability of the fuel cell system.

[0012] To achieve the above objectives, the main point of the technology described in the second invention is that, in the technology described in the first invention, the control device learns the simultaneously measured current measurement values, prioritizes the fuel cell with the higher current measurement value among the learned multiple current measurement values ​​to generate electricity, and makes the number of fuel cells generating electricity vary according to the output requirements of the fuel cell system.

[0013] According to the structure of the above-described technology, in addition to the effects of the technology described in the first invention, the control device prioritizes the generation of fuel cells with higher current measurement values ​​among the multiple learned current measurement values, and adjusts the number of fuel cells generating power according to the required output of the fuel cell system. Therefore, it is possible to generate power while suppressing fuel cells with low current measurement values ​​that pose a risk of degradation, and to generate power in accordance with the required output.

[0014] To achieve the above objectives, the main point of the third invention is that, in the second invention, the outputs of multiple fuel cells are set to be the same as each other, and the maximum required output of the fuel cell system is met by the power generation of N fuel cells. The total number of fuel cells is set to be more than N+1. The control device uses N fuel cells corresponding to the first N current measurement values ​​in descending order of the multiple current measurement values ​​learned to generate electricity.

[0015] According to the structure of the above technology, in addition to the function of the technology described in the second invention, the control device uses the N fuel cells corresponding to the first N current measurement values ​​in descending order of the (N+1) current measurement values ​​learned to generate electricity, so that one fuel cell not used for generating electricity can be set as a standby.

[0016] To achieve the above objectives, the main point of the fourth invention is that, in the technology described in the first invention, there is also an alarm device for notifying the fuel cell of deterioration. When the measured current value of the fuel cell is lower than a first current determination value, the control device considers that the fuel cell is at risk of deterioration and causes the alarm device to issue a warning notification. When the measured current value of the fuel cell is lower than a second current determination value that is lower than the first current determination value, the control device considers that the fuel cell has an abnormal deterioration and causes the alarm device to issue an abnormal notification.

[0017] Based on the structure of the above-described technology, in addition to the functions of the technology described in the first invention, when the measured current value of the fuel cell is lower than the first current determination value, the control device activates the alarm device to issue a warning notification, thus allowing the user to be aware in advance that the fuel cell is at risk of deterioration. Furthermore, when the measured current value of the fuel cell is lower than the second current determination value, the control device activates the alarm device to issue an abnormality notification, thus allowing the user to be aware in advance that the fuel cell is experiencing deterioration.

[0018] To achieve the above objective, the essence of the fifth invention is that, in the fourth invention, the control device is configured to measure the voltage of the storage battery, and to change the first current determination value and the second current determination value according to the measured voltage value.

[0019] According to the structure of the above-mentioned technology, in addition to the function of the technology described in the fourth invention, the first current determination value and the second current determination value used by the control device to determine the deterioration risk and deterioration abnormality of the fuel cell vary according to the voltage measurement value of the battery.

[0020] The effects of the invention

[0021] According to the technology described in the first invention, it is possible to suppress the individual degradation of multiple fuel cells and to suppress the reduction in the durability of the fuel cell system.

[0022] According to the technology described in the second invention, in addition to the effects of the technology described in the first invention, it is also possible to meet the required output while suppressing the widening of the degradation difference between multiple fuel cells.

[0023] According to the technology described in the third invention, in addition to the effects of the technology described in the second invention, the durability of the fuel cell system can be extended.

[0024] According to the technology described in the fourth invention, in addition to the effects of the technology described in the first invention, users can recognize the individual deterioration risks and abnormalities of multiple fuel cells in advance and can take preventive measures.

[0025] According to the technology described in the fifth invention, in addition to the effects of the technology described in the fourth invention, the degradation of the fuel cell can be accurately determined regardless of the difference in the voltage state of the battery. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the fuel cell system related to the first embodiment.

[0027] Figure 2 This is a schematic diagram showing the associated structure of the first FC stack in relation to the first embodiment.

[0028] Figure 3This is a graph illustrating, in relation to the first embodiment, an example of the relationship between (A) FC current and FC voltage and (B) battery current and battery voltage in the absence of power consumption in the motor.

[0029] Figure 4 This is a graph illustrating, in relation to the first embodiment, an example of the relationship between FC current and FC voltage for each FC stack, where (A) the degree of degradation differs, and (B) the relationship between battery current and battery voltage, in the absence of motor power consumption.

[0030] Figure 5 This is a flowchart illustrating an example of the power generation control of three FC stacks in relation to the first embodiment.

[0031] Figure 6 It specifies a judgment value mapping for warning judgment values ​​and abnormal judgment values ​​of FC current corresponding to the battery voltage, in relation to the first embodiment.

[0032] Figure 7 This is a flowchart illustrating an example of the power generation control of three FC stacks in relation to the second embodiment. Detailed Implementation

[0033] <First Implementation Method>

[0034] Hereinafter, a first embodiment of a fuel cell system embodied in an electric vehicle will be described in detail with reference to the accompanying drawings.

[0035] [Regarding the structure of fuel cell systems]

[0036] exist Figure 1 The fuel cell system 1 according to this embodiment is illustrated by a schematic structural diagram. Figure 1 As shown, the fuel cell system 1 of this embodiment is configured as a simple DC-DC converter-free system. This fuel cell system 1 includes three FC stacks, namely a first FC stack 11A, a second FC stack 11B, and a third FC stack 11C, a battery 12, and a motor 13. An inverter can also be installed instead of the motor 13.

[0037] Each FC stack 11A-11C has the same "2kW" power output. Each FC stack 11A-11C and motor 13 are connected in parallel with battery 12. Each FC stack 11A-11C has a diode 14A, 14B, or 14C connected in series. Each FC stack 11A-11C is equivalent to an example of a "fuel cell" of the present disclosure.

[0038] Here, a DC-DC converter is a device that converts DC to DC to convert the voltage used in the system to DC.

[0039] [Regarding the associated structures of the FC heap]

[0040] exist Figure 2 The diagram below illustrates the associated structure of the first FC stack 11A. Figure 2 As shown, the first FC stack 11A is configured as an open cathode system. That is, a hydrogen system 21 and an air and cooling system 22 are provided in the first FC stack 11A. The first FC stack 11A receives a supply of hydrogen from the hydrogen system 21 and a supply of air from the air and cooling system 22 to generate electricity.

[0041] The power generated by the first FC stack 11A is fed into the battery 12 via wiring. The power fed into the battery 12 is supplied to the motor 13 via wiring. The motor 13 is driven by receiving power from the first FC stack 11A and / or the battery 12 via wiring.

[0042] The hydrogen system 21 is located on the anode side of the first FC stack 11A. The hydrogen system 21 includes a hydrogen supply passage 31, an exhaust and drainage passage 32, and a filling passage 33.

[0043] Hydrogen supply passage 31 is a passage for supplying hydrogen from hydrogen tank 41 containing hydrogen to the first FC stack 11A. Exhaust and drainage passage 32 is a passage for discharging hydrogen (i.e., hydrogen exhaust gas) and wastewater discharged from the first FC stack 11A.

[0044] Additionally, the hydrogen system 21 includes, in the hydrogen supply passage 31, a hydrogen valve 51, a hydrogen pressure reducing valve 52, and an injector 53, sequentially arranged from the hydrogen tank 41 side. The filling passage 33 is a passage for filling hydrogen into the hydrogen tank 41 from the filling port 42.

[0045] Hydrogen valve 51 is a solenoid valve used to switch the supply and cut-off of hydrogen from hydrogen tank 41 to hydrogen supply passage 31. Hydrogen pressure reducing valve 52 is a pressure regulating valve used to reduce the pressure of hydrogen, and is, for example, composed of a solenoid valve. Injector 53 is a solenoid valve that injects hydrogen discharged from hydrogen tank 41 downstream. Injector 53 is configured, for example, to adjust the opening of the injection port by moving a needle valve, thereby adjusting the hydrogen injection pressure (hydrogen pressure).

[0046] An exhaust drain valve 54 is installed in the exhaust drain passage 32. The exhaust drain valve 54 is a solenoid valve used to switch the discharge and shut-off of hydrogen waste gas and moisture.

[0047] In the hydrogen system 21, a pressure sensor 16 is provided in the hydrogen supply passage 31 between the injector 53 and the first FC stack 11A. The pressure sensor 16 is used to measure the pressure of the hydrogen ejected from the injector 53, that is, the pressure of the hydrogen supplied to the first FC stack 11A.

[0048] On the other hand, an air and cooling system 22 is separately provided on the cathode side of each FC stack 11A-11C. Each air and cooling system 22 corresponding to each FC stack 11A-11C includes an air passage 61 for circulating air and an electrically powered air supply fan 62 for supplying air flowing in the passage 61 to each FC stack 11A-11C. In this embodiment, the air system is configured as a cathode-open system that also serves as a cooling system.

[0049] In the above-described structure associated with the first FC stack 11A, the hydrogen supplied to the FC stack 11A from the hydrogen supply passage 31 is used for power generation in the FC stack 11A and is then discharged to the outside as hydrogen exhaust gas from the FC stack 11A via the exhaust and drainage passage 32. Additionally, the air supplied to the first FC stack 11A from the air passage 61 is used for power generation in the FC stack 11A and is then discharged to the outside as air exhaust gas from the FC stack 11A.

[0050] The power generated by the first FC stack 11A is used to charge the battery 12 or to drive the motor 13.

[0051] Furthermore, the second and third FC stacks 11B and 11C also possess the same associated structure as described above and operate in the same manner. Their descriptions are omitted here.

[0052] like Figure 1 As shown, the fuel cell system 1 also includes a control device 20 for controlling the system 1. The control device 20 includes, for example, a processing unit such as a CPU, a storage unit, and an input / output interface unit. The storage unit includes a ROM storing control programs and control data processed by the CPU, and RAM used for various operating areas of the control processing. The control device 20 executes various controls of the fuel cell system 1 according to the control programs stored in the storage unit. In particular, in this embodiment, the control device 20 controls various devices of the hydrogen system 21 and the air and cooling system 22 in order to control the fuel cell system 1.

[0053] In this embodiment, the control device 20 measures the voltage of the battery 12 (battery voltage) using a voltage measuring circuit installed inside it. Additionally, the control device 20 measures the power generation current (FC current) of each FC stack 11A-11C using a current measuring circuit installed inside it. The control device 20 controls the power generation of each FC stack 11A-11C based on the measured battery voltage and FC current.

[0054] [Regarding systems without DC-DC converters]

[0055] The fuel cell system 1 of this embodiment is configured as a system without a DC-DC converter. Therefore, in the fuel cell system 1, the FC voltage of each FC stack 11A-11C is equal to (or approximately equal to) the battery voltage of the storage battery 12. As a result, the FC current depends on the battery voltage. In other words, the fuel cell system 1 can supply the power generated by the FC stacks 11A-11C to the storage battery 12 and the motor 13 without converting the FC voltage.

[0056] In this fuel cell system 1, the FC voltage is equal to the battery voltage, so each FC stack 11A~11C generates electricity on demand, corresponding to the battery voltage. Furthermore, when the charging rate of the battery 12 increases, the air supply fan 62 stops, causing the FC voltage to fall below the battery voltage and intermittently stopping the power generation of each FC stack 11A~11C, thus achieving low-current power generation. This allows for an increase in fuel efficiency.

[0057] exist Figure 3 The diagram illustrates an example of the relationship between (A) FC current and FC voltage, and (B) battery current and battery voltage, in the case where there is no power consumption in the motor 13 of the fuel cell system 1. Figure 3 As shown, if the battery voltage is set to "49V" when there is no power consumption in motor 13, the FC voltage is equal to the battery voltage, which is "49V". Therefore, the FC current is "30A". Thus, "FC output = 49V × 30A = 1.5kW" and "battery output = 49V × -30A = -1.5kW" become "FC output = 49V × -30A = -1.5kW".

[0058] Here, the fuel cell system 1 has three FC stacks 11A to 11C, therefore, the degree of degradation sometimes differs among the FC stacks 11A to 11C. Figure 4 The diagram illustrates, in the absence of power consumption in motor 13, an example of the relationship between FC current and FC voltage for each FC stack 11A~11C with varying degrees of degradation (A) and the relationship between battery current and battery voltage.

[0059] exist Figure 4 Regarding the degree of degradation of each FC stack 11A~11C, the third FC stack 11C has the largest FC current at "28A". The first FC stack 11A has the second largest FC current at "30A". The second FC stack 11B has the smallest FC current at "32A". The degradation of each FC stack 11A~11C is trending towards... Figure 4The degradation intensifies in the direction indicated by the thick arrow Y1 in (A). If the three FC stacks 11A to 11C are operated without considering such differences in degradation, the durability of the third FC stack 11C and the first FC stack 11A, which have greater degradation than the other FC stacks, will decrease more rapidly, potentially reducing the durability of the fuel cell system 1. Therefore, in this embodiment, the power generation control of the three FC stacks 11A to 11C is performed as follows.

[0060] [Regarding the power generation control of the three FC reactors]

[0061] exist Figure 5 In this embodiment, a flowchart illustrates an example of the power generation control of the three FC stacks 11A to 11C. The control program described in this flowchart is stored in the storage unit of the control device 20.

[0062] When processing is transferred Figure 5 In the illustrated routine, the control device 20 determines in step 100 whether the "required output" for the fuel cell system 1 is "4 (kW)" or higher. In this embodiment, each FC stack 11A-11C is set to generate the same "2 (kW)" of electricity. This "4 (kW)" is the power output that can be satisfied by the power generation of two of the three FC stacks 11A-11C. Furthermore, the "required output" reflects the acceleration operation of the electric vehicle driver. If the control device 20 determines the result is positive, it proceeds to step 110; if the result is negative, it proceeds to step 140.

[0063] In step 110, control device 20 causes the three FC stacks 11A-11C to generate electricity on demand. Therefore, control device 20 activates the air supply fan 62 of the air and cooling system.

[0064] Next, in step 120, the control device 20 simultaneously measures the FC current of all FC stacks 11A to 11C.

[0065] Next, in step 130, the control device 20 learns the FC current of each FC stack 11A~11C, and learns the number (identification number) of FC stack 11A~11C in descending order of FC current, and temporarily ends the subsequent processing.

[0066] On the other hand, in step 140, the control device 20 determines whether the "required output" is "2~4 (kW)". If the control device 20 determines the result is yes, the process is transferred to step 150; if the result is no, the process is transferred to step 160.

[0067] In step 150, control device 20 causes the two FC stacks 11A-11C with high FC current to generate electricity on demand. Therefore, control device 20 activates air supply fan 62, temporarily suspending subsequent processing.

[0068] On the other hand, in step 160, the control device 20 determines whether the "required output" is "0.5~2 (kW)". If the control device 20 determines the result is yes, the process is transferred to step 170; if the result is no, the process is transferred to step 180.

[0069] In step 170, control device 20 causes the FC stacks 11A-11C with the high FC current to "generate power on demand". Therefore, control device 20 activates air supply fan 62, temporarily suspending subsequent processing.

[0070] On the other hand, in step 180, the control device 20 causes all FC stacks 11A-11C to "intermittently stop". Therefore, the control device 20 stops the air supply fan 62, temporarily terminating the subsequent processing.

[0071] According to the power generation control described above, the control device 20 is configured to simultaneously measure the FC current of the three FC stacks 11A to 11C. Furthermore, the control device 20 controls the power generation of the three FC stacks 11A to 11C based on the differences in the simultaneously measured FC currents of each FC stack 11A to 11C.

[0072] According to the power generation control described above, the control device 20 learns the FC current of each FC stack 11A~11C measured simultaneously. In addition, the control device 20 prioritizes the FC stack 11A~11C with the highest FC current among the three learned FC currents to generate electricity, and the number of FC stacks 11A~11C generating electricity varies according to the output requirements of the fuel cell system 1.

[0073] Based on the power generation control described above, the maximum required output of the fuel cell system 1 is met by power generation from "4 (kW)," that is, "2 (N=2)" FC stacks 11A to 11C. Furthermore, the total number of FC stacks 11A to 11C is set to "3," that is, "N+1" or more. Then, the control device 20 uses the "2 (N=2)" FC stacks 11A to 11C corresponding to the first two FC currents in descending order of the three learned FC currents for power generation.

[0074] [Diagnosis of degradation anomalies in FC heaps]

[0075] like Figure 1As shown, in this embodiment, the control device 20 is configured to diagnose deterioration anomalies in each FC stack 11A to 11C. Additionally, an alarm device 70 is provided to notify the diagnostic results. The control device 20 controls the alarm device 70 based on the diagnostic results.

[0076] In this embodiment, for each FC stack 11A~11C, the degradation anomaly of each FC stack 11A~11C is diagnosed based on the difference in FC current corresponding to the battery voltage. Figure 6 The table shows the mapping of "warning judgment values" and "abnormal judgment values" for the FC current corresponding to the "battery voltage". Figure 6 In the case where the "battery voltage" is "48V, 49V, 50V, 51V, 52V", the "warning judgment value" related to the FC current is "29A, 28A, 27A, 26A, 25A". Here, the "warning judgment value" is equivalent to an example of the "first judgment value" of the present disclosure. In addition, the "abnormal judgment value" is equivalent to an example of the "second judgment value" of the present disclosure.

[0077] exist Figure 6 In the event that the FC current is at a "warning threshold" relative to the "battery voltage," the control device 20 activates the alarm device 70 to issue a warning notification. This warning notification is used to notify at least one of the FC stacks 11A to 11C that there is a risk of deterioration. For example, when the "battery voltage" is "48V" and the FC current is "29A," the control device 20 activates the alarm device 70 to issue a warning notification.

[0078] On the other hand, Figure 6 In the event that the FC current is an "abnormal judgment value" relative to the "battery voltage", the control device 20 activates the alarm device 70 to notify that at least one of the FC stacks 11A to 11C has deteriorated. For example, when the "battery voltage" is "48V" and the FC current is "26A", the control device 20 activates the alarm device 70 to notify that an abnormality has occurred.

[0079] In this embodiment, for example, the alarm device 70 is configured to sound and flash. In this case, the "warning notification action" and the "abnormality notification action" can be distinguished by making the alarm device 70 sound and flash in different modes. Furthermore, the control device 20 stores diagnostic results related to the deterioration of each FC stack 11A-11C in a storage device. These diagnostic results can be confirmed by reading them from the storage unit during regular vehicle inspections. Alternatively, the alarm device 70 can be configured to have a communication device. In this case, it can be configured to communicate with a server via the communication device, sending commands to the control device 20 to urge the replacement of the corresponding electric vehicle's FC stack or to disable the operation of the corresponding FC stack.

[0080] In the aforementioned degradation anomaly diagnosis, if the FC current is lower than the "warning judgment value," the control device 20 considers that the FC stacks 11A-11C are at risk of degradation and triggers the alarm device 70 to issue a warning notification. Conversely, if the FC current is lower than the "abnormal judgment value," which is lower than the "warning judgment value," the control device 20 considers that the FC stacks 11A-11C are experiencing a degradation anomaly and triggers the alarm device 70 to issue an abnormality notification.

[0081] In the aforementioned deterioration and abnormality diagnosis, the control device 20 is configured to measure the voltage of the battery 12. Furthermore, the control device 20 causes the "warning judgment value" and "abnormality judgment value" to change according to the battery voltage.

[0082] [Regarding the role and effects of fuel cell systems]

[0083] According to the structure of the fuel cell system 1 of this embodiment described above, the control device 20 simultaneously measures the current of the three FC stacks 11A to 11C, and controls the power generation of the three FC stacks 11A to 11C based on the difference in the FC current of each FC stack 11A to 11C measured simultaneously. Therefore, it is possible to use the FC stacks 11A to 11C with high FC current and less degradation for power generation, and to suppress the use of the FC stacks 11A to 11C with low FC current and a risk of degradation for power generation. Therefore, it is possible to suppress the degradation of each of the three FC stacks 11A to 11C, and to suppress the decrease in the durability of the fuel cell system 1.

[0084] According to the structure of this embodiment, the control device 20 prioritizes the generation of FC stacks 11A-11C with the highest learned FC current value, and the number of FC stacks 11A-11C generating power varies according to the required output of the fuel cell system 1. Therefore, it is possible to generate power corresponding to the required output while suppressing the use of FC stacks 11A-11C with low FC current that are at risk of degradation. Thus, it is possible to meet the required output while suppressing the widening of the degradation difference among the three FC stacks 11A-11C.

[0085] According to the structure of this embodiment, the control device 20 uses the two FC stacks 11A-11C corresponding to the first two values ​​in descending order of the learned (2+1) FC currents for power generation, and thus can set the one FC stack 11A-11C that is not used for power generation as a standby. Therefore, the endurance of the fuel cell system 1 can be extended.

[0086] According to the structure of this embodiment, when the FC current is lower than the warning threshold (first current threshold), the control device 20 activates the alarm device 70 to issue a warning notification, thus allowing the user to be aware in advance that there is a risk of degradation in the FC stacks 11A to 11C. Furthermore, when the FC current is lower than the anomaly threshold (second current threshold), the control device 20 activates the alarm device 70 to issue an anomaly notification, thus allowing the user to be aware in advance that there is an anomaly in the FC stacks 11A to 11C. Therefore, the user can recognize the individual degradation risks and anomalies of the three FC stacks 11A to 11C in advance and take preventative measures.

[0087] According to the structure of this embodiment, the control device 20 changes the warning judgment value and the abnormal judgment value used to determine the deterioration danger and deterioration abnormality of the FC stacks 11A to 11C based on the value of the battery voltage. Therefore, the deterioration of the FC stacks 11A to 11C can be accurately determined regardless of the difference in the state of the battery voltage.

[0088] <Second Implementation Method>

[0089] Next, a second embodiment of the fuel cell system, specifically a fuel cell system mounted on an electric vehicle, will be described with reference to the accompanying drawings. Furthermore, in the following description, structural elements equivalent to those in the first embodiment will be labeled with the same reference numerals and their descriptions will be omitted; the description will focus on the differences.

[0090] [Regarding the power generation control of the three FC reactors]

[0091] The difference between this embodiment and the first embodiment lies in the power generation control of the three FC stacks 11A~11C. Figure 7 In this embodiment, a flowchart illustrates an example of other aspects of the power generation control of the three FC stacks 11A to 11C. The control program described in this flowchart is stored in the storage unit of the control device 20.

[0092] When processing is transferred Figure 7 In the illustrated routine, in step 200, the control device 20 actively (e.g., once per cycle) causes the three FC stacks 11A-11C to generate power on demand. Therefore, the control device 20 activates the air supply fan 62 of the air and cooling system.

[0093] Next, in step 210, the control device 20 simultaneously measures the FC current of all FC stacks 11A to 11C.

[0094] Next, in step 220, the control device 20 learns the FC current of each FC stack 11A~11C, and learns the number (identification number) of FC stack 11A~11C in descending order of FC current.

[0095] Next, in step 230, the control device 20 determines whether the "required output" is "2 (kW)" or higher. If the control device 20 determines the result is yes, it transfers the processing to step 240; if the result is no, it transfers the processing to step 250.

[0096] In step 240, control device 20 causes the two FC stacks 11A-11C with high FC current to generate electricity on demand. Therefore, control device 20 activates air supply fan 62, temporarily suspending subsequent processing.

[0097] On the other hand, in step 250, the control device 20 determines whether the "required output" is "0.5~2 (kW)". If the control device 20 determines the result is yes, the process is transferred to step 260; if the result is no, the process is transferred to step 270.

[0098] In step 260, control device 20 causes the FC stacks 11A-11C with the highest FC current to generate electricity on demand. Therefore, control device 20 activates air supply fan 62, temporarily terminating the subsequent processing.

[0099] On the other hand, in step 270, the control device 20 causes all FC stacks 11A-11C to "intermittently stop". Therefore, the control device 20 stops the air supply fan 62, temporarily terminating the subsequent processing.

[0100] [Regarding the role and effects of fuel cell systems]

[0101] The structure of the fuel cell system 1 in this embodiment described above differs from that in the first embodiment in terms of the power generation control of the three FC stacks 11A to 11C, but it can achieve the same function and effect as the first embodiment.

[0102] <Other Implementation Methods>

[0103] Furthermore, the present disclosure is not limited to the above-described embodiments, and can also be implemented by appropriately modifying a part of the structure without departing from the spirit of the disclosure.

[0104] (1) In the above embodiment, three FC stacks 11A to 11C are provided as multiple fuel cells, but the number of FC stacks is not limited to three.

[0105] (2) In the above embodiments, the fuel cell system 1 is specifically installed in an electric vehicle, but it can also be specifically installed in a place other than an electric vehicle.

[0106] (3) In the above embodiments, an open cathode system that allows the air system and cooling system to be shared is used in each FC stack 11A~11C, but a closed cathode system that separates the air system and cooling system can also be used.

[0107] Industrial availability

[0108] The technology disclosed herein can be used, for example, in fuel cell systems installed in electric vehicles.

[0109] Explanation of reference numerals in the attached figures

[0110] 1. Fuel Cell System

[0111] 11A First FC Stack (Fuel Cell)

[0112] 11B Second FC Stack (Fuel Cell)

[0113] 11C Third FC Stack (Fuel Cell)

[0114] 12 Storage batteries

[0115] 20 Control devices

[0116] 70 Alarm Device

Claims

1. A fuel cell system comprising a plurality of fuel cells connected in parallel and a single battery connected to all of the plurality of fuel cells, and without a DC-DC converter, characterized in that, It also includes a control device for controlling the power generation of the multiple fuel cells. The control device is configured to simultaneously measure the current of multiple fuel cells and control the power generation of the multiple fuel cells based on the differences in the measured current values ​​of each fuel cell.

2. The fuel cell system according to claim 1, characterized in that, The control device learns the simultaneously measured current values, prioritizes the fuel cell with the highest current value among the learned current values ​​to generate electricity, and adjusts the number of fuel cells generating electricity according to the output requirements of the fuel cell system.

3. The fuel cell system according to claim 2, characterized in that, The outputs of the multiple fuel cells are set to be the same as each other. The configuration is such that the maximum required output of the fuel cell system is met by the power generation of N fuel cells, and the total number of fuel cells is set to be N+1 or more. The control device will use the N fuel cells corresponding to the first N current measurements in descending order of the learned current measurements to generate electricity.

4. The fuel cell system according to claim 1, characterized in that, It also includes an alarm device for notifying the fuel cell of deterioration. If the measured current value of the fuel cell is lower than the first current determination value, the control device considers the fuel cell to be in danger of deterioration and causes the alarm device to issue a warning notification. If the measured current value of the fuel cell is lower than the second current determination value, which is lower than the first current determination value, the control device considers the fuel cell to be in abnormal deterioration and causes the alarm device to issue an abnormal notification.

5. The fuel cell system according to claim 4, characterized in that, The control device is configured to measure the voltage of the battery, and to change the first current determination value and the second current determination value according to the measured voltage value.

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