Fuel cell vehicle state determination device, fuel cell vehicle, computer program, and recording medium

Abstract

To make it possible to more accurately determine a state such as deterioration of a fuel cell even during running of a vehicle.SOLUTION: According to one viewpoint of the present disclosure, a fuel cell vehicle state determination device includes one or more processors and one or more memories communicably connected to the one or more processors. The processors measure amplitudes of a current and a voltage obtained from a fuel cell only for a predetermined period of time, and detect if there is a specific frequency component corresponding to mass transport resistance of the fuel cell. When the specific frequency component is detected, the processors extract low frequency components for the respective current and voltage obtained from the fuel cell, and on the basis of, the extracted low frequency current signal and low frequency voltage signal, calculates an AC impedance corresponding to the mass transport resistance of the fuel cell, and determines a state of the fuel cell on the basis of, the calculated AC impedance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a state determination device capable of determining the state, such as deterioration, of a fuel cell mounted on a vehicle, a fuel cell vehicle equipped with the state determination device, a program capable of executing the state determination, and a recording medium for the program. [Background technology]

[0002] In modern society, transportation is essential, and various vehicles, including automobiles, travel on the roads in our daily lives. In recent years, fuel cells, which have a relatively low environmental impact, have been attracting attention as a new power source for supplying driving force to vehicles.

[0003] In such fuel cells, fuel gas (hydrogen) is supplied to one electrode (fuel electrode) and oxidant gas (oxygen) is supplied to the other electrode (air electrode), and electrical energy is generated through a chemical reaction between these. However, since fuel cells may deteriorate depending on their usage conditions, it is necessary to understand the state of the fuel cell, such as its deterioration, in order to continue to obtain appropriate electrical energy (generated power) from the fuel cell.

[0004] It is known that the degradation state of the fuel cell is correlated with the AC impedance characteristics. For example, as exemplified in the following patent documents, the degradation state is determined by calculating the AC impedance characteristics of the fuel cell using a known method such as a frequency response analyzer (FRA) or an FFT method. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-093120 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-267472 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-014284 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-018741 [Patent Document 5] Japanese Patent Application Laid-Open No. 2003-223918 [Patent Document 6] Japanese Patent Application Publication No. 2016-024852 Summary of the Invention [Problem to be solved by the invention]

[0006] Not limited to the above-mentioned patent documents, current technologies still do not meet market needs, and the following problems remain. That is, as shown in the above-mentioned patent documents, when determining the degradation state of a fuel cell, the AC impedance characteristics of the fuel cell are measured by superimposing a measurement signal on the driving current of the fuel cell. Therefore, a memory device for storing the measurement signal and a circuit for superimposing the measurement signal are required. Furthermore, for example, a method for measuring the AC impedance characteristics using the above-mentioned FFT method generally requires expensive equipment capable of high-speed calculations, which increases costs accordingly.

[0007] Furthermore, in the case of fuel cell vehicles equipped with fuel cells, in order to determine the deterioration state of the fuel cell installed in the vehicle while it is running, due to measurement issues, it is assumed that the measurement signal will be operated at around several hundred Hz. However, when operated at around several hundred Hz, current fluctuations while the vehicle is running have a significant effect as measurement errors, making it difficult to accurately measure the AC impedance characteristics described above. The present disclosure has been made in consideration of the above-mentioned problems as an example, and aims to provide a state determination device for a fuel cell vehicle that can more accurately determine the state of the fuel cell, such as deterioration, even while the vehicle is in motion, a fuel cell vehicle equipped with this state determination device, and a computer program and recording medium for determining the state. [Means for solving the problem]

[0008] In order to solve the above-described problems, according to one aspect of the present disclosure, there is provided a state determination device for a fuel cell vehicle including one or more processors and one or more storage devices communicably connected to the one or more processors, wherein the processor: During a period in which the output current and output voltage of the fuel cell fluctuate in response to fluctuations in the required load during driving, The current and voltage values ​​obtained from the fuel cell are measured for a predetermined period of time, and a resistance value corresponding to the material transport resistance of the fuel cell is calculated. Composed of low frequency bands The presence or absence of a specific frequency component is detected, and when the specific frequency component is detected, the current value and the voltage value obtained from the fuel cell are respectively Pass the low frequency components The specific frequency components are extracted via a bandpass filter, and an AC impedance corresponding to the material transport resistance of the fuel cell is calculated based on the current and voltage of the extracted specific frequencies, and the state of the fuel cell is determined based on the calculated AC impedance.

[0009] In order to solve the above problem, according to another aspect of the present disclosure, a fuel cell state determination is performed. A computer program or a recording medium storing the program, which causes a processor to: During a period in which the output current and output voltage of the fuel cell fluctuate in response to fluctuations in the required load during driving, The current and voltage values ​​obtained from the fuel cell are measured for a predetermined period of time, and a resistance value corresponding to the material transport resistance of the fuel cell is calculated. Composed of low frequency bands Detecting the presence or absence of a specific frequency component, and when the specific frequency component is detected, respectively performing the current value and the voltage value obtained from the fuel cell. Pass the low frequency components The specific frequency is filtered through a bandpass filter. number The device executes a process including: extracting components; calculating an AC impedance corresponding to the material transport resistance of the fuel cell based on the current and voltage of the specific frequencies extracted; and determining the state of the fuel cell based on the calculated AC impedance. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to more accurately determine the state of a fuel cell, for example, even while a fuel cell vehicle is running. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a vehicle equipped with a control device according to an embodiment of the present invention; [Figure 2] 2 is a schematic diagram showing the connection relationship between the fuel cell system and a control device according to the embodiment of the present invention. FIG. [Figure 3] FIG. 2 is a block diagram showing an example of the configuration around the control device according to the present embodiment. [Figure 4] 1 is a graph showing, as an example, current fluctuations and voltage fluctuations in a fuel cell vehicle in an actual driving environment. [Figure 5] 4 is a graph showing an example of waveforms (one example) of current values ​​and voltage values ​​that have passed through a band-pass filter. [Figure 6] 3 is a graph showing an example of a Cole-Cole plot diagram of the fuel cell in this embodiment. [Figure 7] 3 is a flowchart showing a method for determining the state of a fuel cell according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, preferred embodiments of the present disclosure will be described. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted. Furthermore, configurations other than those described in detail below may be supplemented as appropriate with elemental technologies and configurations related to known fuel cell systems, methods for calculating AC impedance characteristics, or fuel cell vehicles, including the above-mentioned patent documents.

[0013] <Fuel cell vehicles 100> Fig. 1 is a schematic diagram showing an example of the configuration of a fuel cell vehicle 100 equipped with a fuel cell 1 and its control device 10 according to this embodiment. The fuel cell vehicle 100 shown in Fig. 1 is configured as a four-wheel drive vehicle in which drive torque output from a drive power source 21 that generates drive torque for the vehicle is transmitted to a left front wheel 3LF, a right front wheel 3RF, a left rear wheel 3LR, and a right rear wheel 3RR (hereinafter collectively referred to as "wheels 3" unless a distinction is required). In this embodiment, the drive power source 21 can be, for example, a known electric motor arranged on the front wheel side.

[0014] The electric motors serving as driving force source 21 in this embodiment may be arranged one on each of the front and rear wheels, or one electric motor may be arranged for each wheel 3. In addition to the electric motor described above, driving force source 21 may also include an internal combustion engine such as a gasoline engine, a diesel engine, or a gas turbine engine.

[0015] A power supply system that supplies desired electric power to such driving force source 21 includes fuel cell 1, a hydrogen gas supply unit including a known hydrogen tank 23 and piping, an air supply unit including a known compressor 31 and piping, a known secondary battery 50 such as a lithium ion secondary battery or a lead storage battery, a converter 22, and a control device 10 that controls these. In this power supply system, each of fuel cell 1 and secondary battery 50 can supply electric power to a load including the electric motor described above.

[0016] The fuel cell 1 has a stack structure in which a plurality of well-known unit cells are stacked. As an example, the fuel cell 1 of this embodiment can be a polymer electrolyte fuel cell (PEFC). Each unit cell constituting the fuel cell 1 has an anode flow path through which hydrogen flows to the anode side via a well-known electrolyte membrane, and a cathode flow path through which oxygen flows to the cathode side. As shown in FIG. 1, the fuel cell 1 is connected to a load including a driving force source 21 (electric motor) via a converter 22 and wiring.

[0017] As shown in FIGS. 1 and 2, the current value and voltage value of the fuel cell 1 are detected by a known current sensor SR1 and voltage sensor SR2, respectively. In addition, the fuel cell vehicle 100 of this embodiment is configured with a known bandpass filter 43 (in this example, a current-side bandpass filter 43a and a voltage-side bandpass filter 43b) that filters the current and voltage values ​​of the fuel cell 1 measured, for example, while driving. In the following, a bandpass filter will be used as a configuration for filtering the current and voltage values ​​of the fuel cell 1 described above, but this embodiment is not limited to filtering using such hardware, and this filtering process may also be realized by software.

[0018] 2, in the fuel cell vehicle 100 of this embodiment, by passing a bandpass filter 43a that passes a specific frequency component (for example, a relatively low frequency such as 1 to several Hz, hereinafter also referred to as the "specific frequency component") through the current value from the fuel cell 1, the control device 10 can obtain a current value from which only the low frequency component has been extracted. Similarly, by passing a bandpass filter 43b that passes the specific frequency component through the voltage value from the fuel cell 1, the control device 10 can obtain a voltage value from which only the low frequency component has been extracted. In this manner, in this embodiment, a specific frequency component corresponding to the mass transport resistance of the fuel cell is defined as a specific frequency component, and specifically, this specific frequency component is set to a low frequency band of 1 to several Hz.

[0019] The control device 10 then measures the AC impedance characteristics of the fuel cell 1 using, for example, a method using a known FRA (frequency response analyzer) based on the current and voltage values ​​of the specific frequency components that have passed through the bandpass filter 43. As mentioned above, in the prior art, due to measurement issues, it is assumed that measurement signals will be used at around several hundred Hz, but in this embodiment, the AC impedance characteristics are measured based on the specific frequency components that correspond to mass transport resistance among current values ​​that include AC components that are accidentally generated by accelerator operation while driving.

[0020] Therefore, according to this embodiment, there is no need to separately generate and store a measurement signal as in the prior art, and it is possible to measure the AC impedance characteristics of the fuel cell 1 using a known FRA based on the low-frequency signal generated by accelerator operation during actual driving. Note that in this embodiment, the AC impedance characteristics are calculated using the FRA based on the current and voltage values ​​obtained from the fuel cell, but this calculation method is not limited to this, and other known AC impedance calculation methods that use current and voltage values ​​may be used as long as they do not unnecessarily increase the circuit size.

[0021] Converter 22 includes a known AC / DC converter that converts DC current to AC current, and a known DC / DC converter that adjusts the voltage of DC current to a desired voltage. As an example, converter 22 of this embodiment has a function of receiving a control signal from control device 10 to set the output voltage generated and output by fuel cell 1, and a function of boosting the power generated by fuel cell 1 to a desired voltage when supplying it to a load.

[0022] The fuel cell vehicle 100 of this embodiment also includes the above-mentioned driving force source 21, electric steering device 8, and brake devices 4LF, 4RF, 4LR, and 4RR (hereinafter collectively referred to as "brake device 4" unless a distinction is required) as equipment used for driving control. The driving force source 21 outputs driving torque that is transmitted to the front drive shaft 2F and the rear drive shaft 2R via a known transmission (not shown) and a front wheel differential mechanism 5F and a rear wheel differential mechanism 5R, respectively. The driving of the driving force source 21 and the transmission is controlled by a vehicle control device 20 configured to include one or more electronic control units (ECUs: Electronic Control Units).

[0023] The front wheel drive shaft 2F is provided with an electric steering device 8. The electric steering device 8 includes an electric motor and a gear mechanism (not shown), and is controlled by a vehicle control device 20 to adjust the steering angles of the left front wheel 3LF and the right front wheel 3RF.

[0024] The vehicle control device 20 includes, for example, one or more known electronic control units (ECUs) that control the drive of a driving force source 21 that outputs driving torque for the fuel cell vehicle 100, an electric steering device 8 that controls the steering wheel 9 or the steering angle of the steering wheels, and a brake device 4 that controls the braking force of the fuel cell vehicle 100. The vehicle control device 20 may also have a function of controlling the drive of a transmission that changes the speed of the output output from the driving force source 21 and transmits it to the wheels 3.

[0025] [Example of fuel cell system configuration] Next, with reference to FIG. 2, the configuration of the fuel cell and its surroundings in the fuel cell vehicle 100 of this embodiment will be described. The hydrogen gas supply unit capable of supplying hydrogen to the fuel cell 1 may include a pipe (hydrogen supply flow path FC1) connecting the hydrogen tank 23 to the fuel cell 1, a pipe (circulation flow path FC2) for circulating the anode off-gas discharged from the fuel cell 1 to the above-mentioned hydrogen supply flow path, and a pipe (hydrogen release flow path FC3) for releasing the anode off-gas to the atmosphere.

[0026] In this hydrogen gas supply section, hydrogen gas stored in hydrogen tank 23 is supplied to the anode-side flow path of fuel cell 1 via a hydrogen intake valve 32a, a pressure reducing valve, an injector (none of which are shown), and other components having known structures that are installed in hydrogen supply flow path FC1. The flow rate of hydrogen circulating through circulation flow path FC2 is adjusted by a known circulation pump 45. The amount of hydrogen supplied to fuel cell 1 by the injector and the drive rate of circulation pump 45 are adjusted by control device 10 in accordance with the load demand within fuel cell vehicle 100.

[0027] A portion of the hydrogen gas flowing through the circulation flow path FC2 is released (exhausted) to the atmosphere at a predetermined timing through the opening and closing operation of a hydrogen exhaust valve 32b installed in a hydrogen release flow path FC3 branching off from the circulation flow path FC2 under the control of the control device 10. This makes it possible to discharge impurities (such as water vapor and nitrogen) in the hydrogen gas circulating within the circulation flow path FC2 to the outside of the system.

[0028] On the other hand, the air supply unit capable of supplying air to the fuel cell 1 may include, in addition to the above-mentioned compressor 31, an air supply flow path FC4 in which this compressor 31 is installed and which is connected to the fuel cell 1, an oxygen intake valve 32c installed in this air supply flow path FC4 to adjust the amount of oxygen (air) supplied to the fuel cell 1, a flow dividing valve 44, an air release flow path FC5, an air branch flow path FC6, an air exhaust valve (back pressure valve) 32d, and a known flow sensor (not shown). The air supply flow path FC4 is composed of known piping that supplies the air taken in by the above-mentioned compressor 31 to the fuel cell 1.

[0029] The flow dividing valve 44 is a known valve mechanism installed in this air supply flow path FC4, and has the function of adjusting the amount of air that is not supplied to the fuel cell 1 but is supplied directly to the diluter 41 via the air branch flow path FC6. There are no particular restrictions on the structure of the diluter 41, and various known diluters that can be mounted on a vehicle may be used.

[0030] The air taken in by the compressor 31 is supplied to the cathode-side flow path in the fuel cell 1 via the oxygen intake valve 32c and a known humidifier 42. The air supplied to the fuel cell 1 is also supplied as cathode off-gas to a known diluter 41 via an air discharge flow path FC5 under the control of the oxygen discharge valve (back pressure valve) 32d by the control device 10.

[0031] The control device 10 can adjust the concentration of hydrogen gas supplied to the diluter 41 to a predetermined concentration or less (for example, 4% or less) by controlling the flow dividing valve 44. The humidifier 42 of this embodiment may be omitted as appropriate.

[0032] <Control device 10> Next, with reference to FIG. 3, the functions of the control device 10 according to this embodiment and the connection relationships between the various elements in the fuel cell vehicle 100 will be specifically described. As shown in the figure, the control device 10 of this embodiment is configured to include one or more processors (CPUs (Central Processing Units)) having a known structure, and one or more storage devices M communicably connected to the one or more processors. The control device 10 may be configured to be connectable to a known external network NET such as the Internet via various known communication devices 36, such as a smartphone. Note that while FIG. 3 illustrates a memory M1 as an example of the storage device M separate from the control device 10, the storage device M may also be built into the control device 10.

[0033] Such control device 10 is electrically connected, either directly or via communication means such as CAN (Controller Area Network) or LIN (Local Inter Net), to a compressor 31, a valve group 32 (hydrogen intake valve 32a, hydrogen exhaust valve 32b, oxygen intake valve 32c, and oxygen exhaust valve 32d), sensors 33, a publicly known navigation device 34 and notification device 35 (speaker SP and display DP), communication device 36, sensors SR, and memory device M.

[0034] Of these, the storage device M may be configured with at least one of a known memory M1 such as a RAM (Random Access Memory) or a ROM (Read Only Memory), and a known hard disk M2 such as a hard disk. However, the configuration of the storage device M is not limited to the above configuration, and the hard disk M2 may be omitted. The storage device M may store information such as computer programs executed by the control device 10, various parameters used in arithmetic processing, detection data, and arithmetic results.

[0035] The sensors SR are configured to include a known current sensor SR1 capable of measuring the current flowing through the fuel cell 1, and a known voltage sensor SR2 capable of measuring the voltage across the fuel cell 1. Note that the sensors SR of this embodiment are not limited to the above sensors, and may be configured to include one or more known sensors that detect, for example, the operating state and behavior of the fuel cell vehicle 100 (hereinafter collectively referred to as the "vehicle running state") and the environment around the vehicle. Examples of sensors that can detect such vehicle running states include known vehicle speed sensors and acceleration sensors. Examples of sensors that can detect the environment around the vehicle include known temperature sensors and humidity sensors.

[0036] 3, the control device 10 includes an FC driving unit 10a, an FC current acquiring unit 10b, an FC voltage acquiring unit 10c, a specific frequency detecting unit 10d, an AC impedance characteristics measuring unit 10e, a state determining unit 10f, and a notification control unit 10g. Note that part or all of the control device 10 may be configured with updatable firmware or the like, or may be a program module or the like executed by commands from a CPU or the like.

[0037] The FC drive unit 10a controls the drive of the fuel cell 1 through the control of the compressor 31 and the valve group 32, for example, in order to obtain the electric power required for the drive power source 21 in response to the accelerator work of the driver.

[0038] The FC current acquisition unit 10b measures the value of the current flowing through the fuel cell 1 via the current sensor SR1 described above. In addition to measuring the current flowing through the fuel cell 1 as is, the FC current acquisition unit 10b is also capable of acquiring a specific frequency component of the current flowing through the fuel cell 1 that has passed through a bandpass filter 43a, as shown in Fig. 2. More specifically, the FC current acquisition unit 10b has a function of extracting a specific frequency component from the AC component of the current value obtained from the fuel cell 1 when a specific frequency component, described below, is detected.

[0039] The FC voltage acquisition unit 10c measures the voltage value applied to the fuel cell 1 via the voltage sensor SR2 described above. In addition to measuring the voltage applied to the fuel cell 1 as is, the FC voltage acquisition unit 10c is also capable of acquiring a specific frequency component of the voltage applied to the fuel cell 1 that has passed through a bandpass filter 43b, as shown in Fig. 2. More specifically, the FC voltage acquisition unit 10c has a function of extracting the specific frequency component from the AC component of the voltage value applied to the fuel cell 1 when the specific frequency component, which will be described later, is detected.

[0040] The specific frequency detection unit 10d is capable of detecting whether or not the specific frequency components are included in the current and voltage values ​​of the fuel cell 1 by detecting whether or not there is a signal passing through the bandpass filters 43a and 43b.

[0041] The AC impedance characteristic measuring unit 10e has a function of calculating the AC impedance corresponding to the mass transport resistance of the fuel cell based on the extracted current signal and voltage signal of the specific frequency. As described above, in this embodiment, it is possible to measure the AC impedance characteristic based on the current value and voltage value obtained from the fuel cell according to a known FRA.

[0042] The state determination unit 10f has a function of determining the state of the fuel cell based on the calculated AC impedance characteristic. More specifically, for example, the state determination unit 10f compares the AC impedance characteristic (reference) in the initial state when the fuel cell 1 begins to be used with the AC impedance characteristic (measurement result) measured by the AC impedance characteristic measurement unit 10e while the vehicle is running. Then, as explained in the prior art of Patent Document 5, for example, the state determination unit 10f can determine whether the fuel cell 1 has deteriorated based on the state transition of the AC impedance characteristic in a known Cole-Cole plot.

[0043] The notification control unit 10g has a function of notifying the presence or absence of deterioration in the fuel cell determined by the state determination unit 10f via the above-mentioned notification device 35. The notification control unit 10g is not essential and may be omitted as appropriate.

[0044] <Method for determining fuel cell status> Next, a method for determining the state of the fuel cell 1 that can be executed by the control device 10 of this embodiment will be described with reference to Figures 4 to 7. The following state determination method is executed by the control device 10 having the above-mentioned components (FC drive unit 10a, etc.). Below, we will explain a method for determining the state of a fuel cell that is executed in a fuel cell vehicle that has a current sensor SR1 that measures the current flowing through the fuel cell 1, a voltage sensor SR2 that measures the voltage applied to the fuel cell 1, and a control device 10 as a state determination device.

[0045] In this case, a computer program that executes an algorithm based on the state determination method may be installed in advance in a ROM (not shown) in the control device 10, or may be stored in the above-mentioned storage device M. Alternatively, the computer program that executes the algorithm based on the state determination method may be stored in a server (not shown) outside the vehicle, and the control device 10 may access it via the communication device 36. In addition, a recording medium (such as a publicly known optical disk or magnetic recording medium) on which a computer program that executes an algorithm based on this state determination method is recorded may be stored in the vehicle, and the above state determination method may be executed by playing this recording medium in the vehicle as appropriate.

[0046] In this embodiment, a computer program is provided that causes a processor to perform processing including measuring current and voltage values ​​obtained from a fuel cell for a predetermined period of time to detect the presence or absence of a specific frequency component corresponding to the material transport resistance of the fuel cell, and when the specific frequency component is detected, extracting the specific frequency component from the current and voltage values ​​obtained from the fuel cell via a bandpass filter, calculating an AC impedance corresponding to the material transport resistance of the fuel cell based on the current and voltage of the specific frequencies extracted, and performing a state determination of the fuel cell based on the calculated AC impedance.

[0047] In addition, in this embodiment, the present invention is also provided as a recording medium storing a computer program that causes a processor to execute processing including measuring current and voltage values ​​obtained from a fuel cell for a predetermined period of time to detect the presence or absence of a specific frequency component corresponding to the material transport resistance of the fuel cell, and when the specific frequency component is detected, extracting the specific frequency component from the current and voltage values ​​obtained from the fuel cell via a bandpass filter, calculating an AC impedance corresponding to the material transport resistance of the fuel cell based on the current and voltage of the specific frequency extracted, and performing a state determination of the fuel cell based on the calculated AC impedance.

[0048] That is, as shown in Fig. 7, in step 1, the FC drive unit 10a of the control device 10 determines whether or not to drive the fuel cell 1. As an example, when the system power supply of the fuel cell vehicle 100 is turned on and the driver steps on the accelerator, the FC drive unit 10a executes control to drive the fuel cell 1 and supply the necessary power to the driving force source 21 (electric motor) from the fuel cell 1. At this time, as shown in Fig. 4 as an example, the value of the current flowing through the fuel cell 1 and its voltage value change according to fluctuations in the required load, such as the driver's accelerator work.

[0049] When it is determined in step 1 that the fuel cell 1 is driven, in the following step 2, the FC current acquisition unit 10b and the FC voltage acquisition unit 10c of the control device 10 acquire the current value and the voltage value in the fuel cell 1, respectively, via the bandpass filter 43.

[0050] Next, in step 3, the specific frequency detection unit 10d of the control device 10 detects whether or not the above-mentioned specific frequency components are included in the current value and voltage value of the fuel cell 1. As described above, a fuel cell vehicle is accelerated and decelerated as needed depending on the accelerator operation of the driver, which causes fluctuations (AC components with various frequencies) in the current value and voltage value generated by the fuel cell 1. Therefore, in this embodiment, the specific frequency detection unit 10d detects whether or not the above-mentioned specific frequency components are included by detecting the presence or absence of a signal that passes through the above-mentioned bandpass filters 43a and 43b. In this embodiment, the specific frequency component is set to a band of 1 to several Hz as a signal that passes through the band-pass filters 43a and 43b.

[0051] When the specific frequency component is detected in step 3, the AC impedance characteristic measuring unit 10e of the control device 10 calculates the AC impedance of the fuel cell 1 based on the extracted current signal and voltage signal of the specific frequency in the following step 4. The extracted current and voltage values ​​are the signals that pass through the band-pass filters 43a and 43b among the current and voltage values ​​that fluctuate in accordance with fluctuations in the required load, as shown in Fig. 5.

[0052] The AC impedance characteristic measurement unit 10e calculates the AC impedance characteristics of the fuel cell 1 as illustrated in FIG. 6 using a known calculation method (a method using a known frequency characteristic analyzer in this embodiment). As shown in FIG. 6, in this embodiment, the AC impedance characteristics are calculated based on current and voltage values ​​in a relatively narrow band (e.g., low-frequency components of 1 to several Hz). Therefore, although the dashed line portion of the AC impedance characteristics in FIG. 6 is an unmeasured portion, this unmeasured portion is omitted from the calculation in this embodiment because the state determination is based on the AC impedance corresponding to the mass transport resistance of the fuel cell (see measurement section MS in FIG. 6). This allows for more accurate fuel cell state determination while minimizing the number of current and voltage measurement samples and reducing costs.

[0053] In the following step 5, the state determination unit 10f of the control device 10 determines the state (deterioration, etc.) of the fuel cell 1 based on the AC impedance characteristics calculated above. More specifically, the state determination unit 10f determines how the AC impedance characteristics illustrated in Fig. 6 have shifted from the characteristics (reference) of the initial state. Note that, as a degradation determination based on the AC impedance characteristics of the fuel cell, known methods such as those exemplified in Japanese Patent Application Laid-Open Nos. 2005-285614 and 2007-265894 can be applied.

[0054] If the state determination unit 10f determines in step 6 that there is degradation in the fuel cell 1, then in step 7 the notification control unit 10g of the control device 10 notifies the occupants that degradation has occurred in the fuel cell 1 via the notification device 35. As a form of this notification, for example, the degradation of the fuel cell may be presented to the occupants via the display DP inside the vehicle, or the occupants may be informed of the degradation of the fuel cell via the speaker SP.

[0055] Then, in the following step 8, the control device 10 determines whether the system of the fuel cell vehicle 100 has been turned off, for example, upon arrival at the destination. If the answer is Yes in step 8, the process is completed, whereas if the answer is No in step 8, the process returns to step 1 and continues as described above.

[0056] In this way, in conventional methods, regardless of whether FRA or FFT is used, the AC impedance is calculated by superimposing the frequency to be measured on the current or voltage. In contrast, in this embodiment, the AC impedance is calculated after passing the target frequency (the specific frequency component described above) through a bandpass filter from the waveforms of the current and voltage values ​​that are naturally obtained when the driver works on the accelerator while driving normally. As a result, the fuel cell state determination method of this embodiment makes it possible to appropriately determine the state of the fuel cell, such as whether it has deteriorated while driving, while keeping costs down, without using the large-scale and expensive circuit configuration required for FFT methods, etc.

[0057] <Variation 1> For example, the control device 10 may determine where the average AC impedance for the average current at the measured time is located relative to a reference load fluctuation of the AC impedance that has been calculated in advance, and evaluate the state (deterioration, etc.) of the fuel cell based on this determination. That is, as the value obtained from the fuel cell 1 via the band pass filter 43, depending on the above-mentioned accelerator work conditions, only the current value or only the voltage value may be extracted.

[0058] Therefore, the average current and voltage values ​​may be calculated from the currents and voltages where the amplitude of the current signal or voltage signal, obtained by passing the specific frequency component through band-pass filter 43, exceeds a predetermined threshold (e.g., a threshold previously set based on the actual driving pattern), and these values ​​may be grouped to calculate the average AC impedance characteristics. Note that the average current may be, for example, the value of 10 waveforms after the current amplitude exceeds the threshold. Furthermore, the grouping (the range of current values ​​when measuring) may be, for example, 100±5 A.

[0059] After measuring the AC impedance characteristics based on the average current and voltage values ​​in this way, deterioration can be determined based on the variation from a reference waveform (a standard reference load variation that can be calculated by experiment or simulation as a reference) in the Rmt (mass transport resistance) component in a Cole-Cole plot, for example. In other words, in this case, typical accelerator work when a general driver drives in an urban area or the like is statistically calculated, and by using this as a reference, the above variation can be determined by comparing it with the accelerator work by the driver of this fuel cell vehicle 100. The deterioration determination is not limited to this example, and may be performed, for example, in accordance with the state transition (how the AC impedance characteristic has shifted) from the initial state, as in the above-described embodiment.

[0060] <Variation 2> In the fuel cell vehicle 100 of the above embodiment, the specific frequency components passed by the bandpass filter 43 are, for example, in a band of 1 to several Hz. However, the present disclosure is not limited to the above embodiment, and for example, only a predetermined frequency (such as 1 Hz or 2 Hz) may be passed through the bandpass filter. In this case, the fuel cell vehicle 100 may be configured to use multiple bandpass filters to pass at least two of the specific frequency components (for example, 1 Hz and 2 Hz).

[0061] For example, a relatively low frequency such as 1 Hz is frequently used in normal accelerator work by a driver. Therefore, by including such a 1 Hz bandpass filter 43, the fuel cell vehicle 100 can acquire a large amount of data suitable for measuring AC impedance characteristics, but since the period is relatively slow, calculations take time and the vehicle is susceptible to the effects of noise.

[0062] On the other hand, a frequency of, for example, 2 Hz corresponds to the small vibrations that occur when a driver places his or her foot on the accelerator pedal, etc. Therefore, by having such a 2 Hz bandpass filter 43, the fuel cell vehicle 100 has the advantage that, although data acquisition is not so frequent, the waveform is stable and the vehicle is less susceptible to the effects of noise. This makes it possible to compensate for the small number of measurement samples with the average value, thereby improving the accuracy of determining the state (deterioration, etc.) of the fuel cell.

[0063] The above-described embodiment and its modified examples are preferred examples of the present disclosure, and new structures and controls may be realized by appropriately combining the elements of the embodiments as long as they do not deviate from the spirit of the present disclosure. [Explanation of symbols]

[0064] 10 Control device 10a FC drive unit 10b FC current acquisition section 10c FC voltage acquisition unit 10d Specific frequency detection section 10f Status determination section 10g Notification control section 31 Compressor 32 Valve group 100 vehicles

Claims

1. one or more processors; one or more storage devices communicatively coupled to the one or more processors; A state determination device for a fuel cell vehicle, comprising: The processor: During a period in which the output current and output voltage of the fuel cell fluctuate in response to fluctuations in the required load while the vehicle is running, the current and voltage values ​​obtained from the fuel cell are measured for a predetermined period of time, and the presence or absence of a specific frequency component constituted by a low frequency band corresponding to the material transport resistance of the fuel cell is detected; When the specific frequency component is detected, the specific frequency component is extracted from the current value and the voltage value obtained from the fuel cell through a band pass filter that passes the low frequency component, calculating an AC impedance corresponding to a mass transport resistance of the fuel cell based on the current and voltage of each of the extracted specific frequencies; determining a state of the fuel cell based on the calculated AC impedance; Fuel cell vehicle status determination device.

2. The processor: Determine where the average AC impedance for the average current during the measured time is located relative to the reference load fluctuation of the AC impedance calculated in advance; evaluating the state of the fuel cell based on the determination; The state determination device for a fuel cell vehicle according to claim 1.

3. a current sensor that measures the current flowing through the fuel cell; a voltage sensor that measures the voltage applied to the fuel cell; The state determination device according to claim 1 ; A fuel cell vehicle with

4. The processor During a period in which the output current and output voltage of the fuel cell fluctuate in accordance with fluctuations in the required load while the vehicle is running, the current and voltage values ​​obtained from the fuel cell are measured for a predetermined period of time, and the presence or absence of a specific frequency component constituted by a low frequency band corresponding to the material transport resistance of the fuel cell is detected; When the specific frequency component is detected, extracting the specific frequency component from the current value and the voltage value obtained from the fuel cell through a band pass filter that passes the low frequency component; calculating an AC impedance corresponding to a mass transport resistance of the fuel cell based on the current and voltage of each of the extracted specific frequencies; determining a state of the fuel cell based on the calculated AC impedance; A computer program that causes a process including the steps of:

5. The processor During a period in which the output current and output voltage of the fuel cell fluctuate in accordance with fluctuations in the required load while the vehicle is running, the current and voltage values ​​obtained from the fuel cell are measured for a predetermined period of time, and the presence or absence of a specific frequency component constituted by a low frequency band corresponding to the material transport resistance of the fuel cell is detected; When the specific frequency component is detected, extracting the specific frequency component from the current value and the voltage value obtained from the fuel cell through a band pass filter that passes the low frequency component; calculating an AC impedance corresponding to a mass transport resistance of the fuel cell based on the current and voltage of each of the extracted specific frequencies; determining a state of the fuel cell based on the calculated AC impedance; A recording medium storing a computer program for executing a process including the steps of:

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