Output control device

Abstract

The present invention provides an output control device that balances the degradation of batteries and fuel cells. [Solution] The output control device includes an acquisition unit that acquires information on the health status SOHf of the fuel cell stack (FCS) that outputs power to operate the motor that is the drive source of the vehicle, and information on the health status SOHb of the battery that outputs power to operate the motor, and further acquires information indicating the requested output Pr from the motor; and a control unit that controls the battery and fuel cell so that when the information on the battery health status is less than or equal to a preset target value Rf, the fuel cell outputs a predetermined first power regardless of the requested output, and the battery outputs a second power corresponding to the requested output, and when the information on the change rate Rb of the battery health is greater than the target value, the battery outputs a predetermined third power regardless of the requested output, and the fuel cell outputs a fourth power corresponding to the requested output.

Description

Technical Field

[0001] The present disclosure relates to an output control device.

Background Art

[0002] There is known a vehicle that has a fuel cell stack (FCS) that generates electric power using hydrogen and a battery (BAT), and drives a motor (electric motor) as a drive source using the electric power output from each to run. In the following description, such a vehicle may be referred to as a fuel cell vehicle (FCV).

[0003] In such a vehicle, electric power is output from the battery and the FCS according to the required output from the motor. The battery deteriorates over time depending on usage, and the amount of electric power (capacity) that can be charged and discharged decreases. On the other hand, the FCS shows deterioration as a decrease in the amount of electric power (voltage) that can be generated. When the deterioration of either the battery or the FCS progresses to a certain extent, it is necessary to stop the operation of the vehicle and replace the deteriorated battery or FCS.

[0004] For example, Patent Document 1 discloses a fuel cell system that varies the supply flow rate of fuel supplied to the FCS so that the voltage of the FCS increases and decreases across the target voltage within a range where the charge-discharge power of the battery does not exceed the allowable charge power while suppressing the current of the FCS to the target current.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, the FCS (Fire Control System) deteriorates and its output decreases as the amplitude of output fluctuations increases and the period shortens. The State of Health (SOH) of the FCS represents the rate of output reduction of the FCS. Also, the more charging and discharging a battery is performed, the more it deteriorates and its capacity decreases. The SOH (SOH) of a battery represents the rate of capacity reduction.

[0007] In the fuel cell system described in Patent Document 1, the State of Health (SOH) of the FCS and battery are monitored separately, and degradation is suppressed independently for each. This makes it difficult to balance the degradation of the FCS and battery, which may result in differences in the number of repairs and replacements required for the FCS and battery.

[0008] As a result, the fuel cell system described in Patent Document 1 would have difficulty maintaining the long-term durability required for commercial vehicles, for example.

[0009] The purpose of this disclosure is to provide an output control device capable of balancing the degradation of batteries and fuel cells. [Means for solving the problem]

[0010] To achieve the above objectives, the output control device in this disclosure is: An acquisition unit that acquires information regarding the health of a fuel cell that outputs power to operate a motor that serves as the drive source for a vehicle, and information regarding the health of a battery that outputs power to operate the motor, and further acquires information indicating the requested output from the motor, A control unit controls the battery and the fuel cell so that, if the information regarding the health of the battery is below a preset target value, the fuel cell outputs a predetermined first power regardless of the requested output, and the battery outputs a second power corresponding to the requested output; and if the information regarding the health of the battery is greater than the target value, the battery outputs a predetermined third power regardless of the requested output, and the fuel cell outputs a fourth power corresponding to the requested output. It is equipped with. [Effects of the Invention]

[0011] According to this disclosure, it is possible to balance the degradation of the battery and the fuel cell. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram showing a fuel cell vehicle equipped with an output control device according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a table showing the relationship between cruising range and SOH, and the relationship between cruising range and variability. [Figure 3] Figure 3 is a graph showing the relationship between cruising range and SOH, and the relationship between cruising range and variability. [Figure 4] Figure 4 is a block diagram showing the functions of the control unit. [Figure 5A] Figure 5A is a diagram illustrating an example of the control methods for the FCS and battery in this embodiment. [Figure 5B] Figure 5B is a diagram illustrating another example of the control methods for the FCS and battery in this embodiment. [Figure 6] Figure 6 is a flowchart showing an example of the operation of the control unit in an embodiment of this disclosure. [Figure 7A] Figure 7A is a diagram showing an example of the control methods for the FCS and battery in Modification Example 1. [Figure 7B] Figure 7B is a diagram illustrating another example of the control methods for the FCS and battery in Modification Example 1. [Figure 7C] Figure 7C is a diagram illustrating another example of the control methods for the FCS and battery in Modification Example 1. [Figure 8] Figure 8 is a flowchart showing an example of the operation of the control unit in Modification Example 1. [Figure 9A] Figure 9A is a diagram illustrating an example of the control methods for the FCS and battery in Modification Example 2. [Figure 9B] FIG. 9B is a diagram showing another example of each control method of the FCS and the battery in Modification 2. [Figure 9C] FIG. 9C is a diagram showing another example of each control method of the FCS and the battery in Modification 2. [Figure 10] FIG. 10 is a flowchart showing an example of the operation of the control unit in Modification 2.

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a fuel cell vehicle equipped with an output control device in an embodiment of the present disclosure. <00xxxx95>

[0014] As shown in FIG. 1, a fuel cell vehicle (FCV) includes a fuel cell system 1, a battery system 2, an electric platform system 3 (electric PF system), and a control system 4 (corresponding to the "output control device" of the present disclosure). ]>

[0015] The fuel cell system 1 has a fuel cell stack 11 (FCS) and a fuel cell control unit 12 (Fuel Cell Stack Electronic Control Unit: FCS ECU). Hydrogen is supplied from a hydrogen tank 5 to the FCS 11. Also, oxygen is supplied to the FCS 11 via an air filter 6. The fuel control unit 12 controls the pressure and amount of hydrogen and oxygen supplied to the FCS 11. The FCS 11 supplies the electricity generated in the process of hydrogen and oxygen changing into water to the motor 31. The fuel cell control unit 12 estimates the current SOH of the FCS 11 and transmits the estimated SOH to the control system 4.

[0016] The battery system 2 includes a battery 21 and a battery management system 22 (BMS). The battery 21 is composed of multiple cells and outputs power to operate the motor 31. The BMS 22 is an electronic control circuit that monitors and controls the charging and discharging of the battery 21. For example, the BMS 22 measures the cell voltage, current, and temperature, and if the cell voltage, current, and temperature exceed a specified range, it controls the disconnection of the power output terminals. This prevents overcharging, over-discharging, overcurrent, etc., of the battery 21. The BMS 22 also estimates the remaining capacity (State of Charge: SOH) of the battery 21. The BMS 22 estimates the current SOH of the battery 21 and transmits the estimated SOH to the control system 4.

[0017] The electric PF system 3 comprises a motor 31, an inverter 32, and a gearbox 33. The motor 31 is the drive motor for the vehicle. The motor 31's rotational speed is controlled by the control system 4 to output the required torque according to the driver's request (accelerator pedal opening). The inverter 32 converts the direct current (DC) supplied to the motor 31 from the FCS 11 and the battery 21, respectively, to alternating current (AC). The gearbox 33 reduces the rotational speed of the motor 31 so that it outputs the required torque. The output torque is transmitted to the wheels 7 of the FCV.

[0018] In a fuel cell vehicle (FCV), which has an FCS11 and a battery21 and drives a motor31 using the power output from the FCS11 and battery21 respectively, if the State of Health (SOH) of the FCS11 and battery21 are monitored separately and degradation is suppressed for each individually, it becomes difficult to balance the degradation of the FCS11 and battery21. This may result in differences in the number of repairs and replacements required for the FCS11 and battery21.

[0019] The control system 4 is a VCU (Vehicle Control Unit) that controls the fuel cell system 1, the battery system 2, and the electric PF system 3, respectively. Specifically, the control system 4 controls the charging and discharging amount of the battery 21 based on the relationship between the requested output from the motor 31 and the output of the FCS 11. The control system 4 also controls the power absorbed during regeneration according to the State of Charge (SOC) of the battery 21. Furthermore, the control system 4 controls the amount of power generated by the FCS 11 according to the requested output from the motor 31. In addition, the control system 4 controls the on / off status of the FCS 11 according to environmental conditions, readiness status, and the vehicle's driving status.

[0020] In this embodiment, the degree of SOH degradation of the FCS11 and the battery 21 is converted into a fluctuation rate from 0 (%) to 100 (%) (corresponding to the "health information" in this disclosure).

[0021] The fuel cell control unit 12 estimates (calculates) the current State of Health (SOH) of the FCS 11. Known methods such as modeling (simulation), constant current / constant voltage testing, and internal resistance measurement are used to estimate the SOH of the FCS 11. In modeling (simulation), a mathematical model that reproduces the degradation mechanism is created to estimate the progress of SOH within the fuel cell control unit 12. In constant current / constant voltage testing, the FCS 11 is charged and discharged with a constant current, or the FCS 11 is operated with a constant voltage, and the SOH is estimated from the response. In the internal resistance measurement method, the internal resistance of the FCS 11 is monitored, and the SOH is estimated from the amount of change.

[0022] The State of Health (SOH) of FCS11 refers to the ratio of the current output P(W) of FCS11 to the output P(W) at the start of use, which is set to 100%. The rate of change of SOH of FCS11 refers to the ratio of the amount of change in SOH from the start of use to the present to the total amount of change in SOH from the start of use to the end of the lifespan of FCS11.

[0023] The BMS22 estimates (calculates) the current State of Health (SOH) of the battery 21. Known methods such as OCV testing, using data from the BMS22, or impedance or internal resistance testing are used to estimate the SOH of the battery 21. In OCV testing, the voltage is measured when the battery 21 is stable, and the SOH is estimated from the relationship ΔSOC (SOC increase) / ΔAh (current increase). Using data from the BMS22, for example, the SOH is estimated from the battery 21's charge / discharge cycles, maximum and minimum voltages, and temperature history. In impedance or internal resistance testing, the impedance or resistance is read, and the SOH is estimated from the change in that value.

[0024] The State of Health (SOH) of battery 21 refers to the current percentage of the battery's full charge capacity, with the battery's full charge capacity at the start of use being defined as 100%. The rate of change of the battery's SOH refers to the ratio of the amount of change in SOH from the start of use to the present to the total amount of change in SOH from the start of use until the end of the battery's lifespan. This makes it possible to relatively monitor the degree of deterioration of the SOH of FCS11 and battery 21 based on the rate of change of their respective SOHs.

[0025] The control system 4 controls the amount of power supplied from the FCS 11 to the motor 31 and from the battery 21 to the motor 31, based on the fluctuation rates of the respective SOH of the FCS 11 and battery 21, in order to balance the degradation of the FCS 11 and battery 21. In the following description, the FCS 11 and battery 21 are collectively referred to as "power sources". The SOH (state of health) of the power sources may also be simply referred to as "SOH" or "health". The fluctuation rate of the SOH of the power sources may also be simply referred to as "fluctuation rate".

[0026] Next, an example of SOH and fluctuation rate will be explained with reference to Figures 2 and 3. Figure 2 is a table showing the relationship between cruising range (km) and SOH (%), and the relationship between cruising range (km) and fluctuation rate (%). In Figure 2, characters are masked with "***". Figure 3 is a graph showing the relationship between cruising range (km) and SOH (%), and the relationship between cruising range (km) and fluctuation rate (%). In Figure 3, the horizontal axis shows cruising range (km), and the vertical axis shows SOH and fluctuation rate (%). In Figures 2 and 3, the health of FCS11 is shown as "SOHf", and the fluctuation rate of the health of FCS11 is shown as "Rf". Also, the health of battery 21 is shown as "SOHb", and the fluctuation rate of the health of battery 21 is shown as "Rb". In Figure 3, SOHf is represented by a thin dashed line, and Rf is represented by a thin solid line. Furthermore, in Figure 3, SOHb is represented by a thick dashed line, and Rb is represented by a thick solid line.

[0027] As shown in Figures 2 and 3, SOHf decreases with the vehicle's range, while Rf increases with the range. Generally, the SOHf at the start of FCS11 use is 100%.

[0028] If we denote the SOHf at the start of FCS11 use as SOHfa, the SOHf at the end of its lifespan as SOHfb, and the current SOHf as SOHfc, then Rf can be calculated using the following formula (1). Rf=(SOHfa-SOHfc) / (SOHfa-SOHfb)*100…(1) Therefore, the Rf at the start of use of FCS11 is 0% (=0 / 100), and the Rf at the end of the lifespan of FCS11 is 100% (=100 / 100).

[0029] As shown in Figures 2 and 3, SOHb decreases with increasing range, while Rb increases with increasing range. Generally, the SOHb of battery 21 is 100% at the start of use.

[0030] If we denote the SOHb of battery 21 at the start of use as SOHba, the SOHb at the end of its lifespan as SOHbb, and the current SOHb as SOHbc, then Rb can be calculated using the following formula (2). Rb=(SOHba-SOHbc) / (SOHba-SOHbb)*100…(2) Therefore, Rb is 0% (=0 / 100) when battery 21 is first used, and Rb is 100% (=100 / 100) when battery 21 reaches the end of its lifespan.

[0031] The control system 4 comprises a control unit 100 and a memory unit 110 (see Figure 4). The memory unit 110 includes a ROM (Read Only Memory) for storing the computer program that implements the control system 4, and a RAM (Random Access Memory) which serves as the working area for the control unit 120. It also includes interfaces such as an AD converter, a DA converter, I / O ports, and CAN. The ROM may be a storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) that stores the OS (Operating System), application programs, and various information referenced when the application programs are executed.

[0032] The control unit 100 is a processor such as the CPU (Central Processing Unit) or GPU (Graphics Processing Unit) of the control system 4, and functions as follows by executing the program stored in the memory unit 110. Note that the control unit 100 is not limited to being composed of a single device. The control unit 100 may be realized by computing resources such as multiple processors and memory. In this case, each part constituting the control unit 100 is realized by at least one of the multiple different processors executing a program.

[0033] The memory unit 110 stores the cruising range (km). The memory unit 110 also pre-stores the SOHfa at the start of use of the FCS 11 and the SOHfb at the end of its lifespan. The memory unit 110 also pre-stores the SOHba at the start of use of the battery 21 and the SOHbb at the end of its lifespan.

[0034] Figure 4 is a block diagram showing the functions of the control unit 100. The control unit 100 functions as an acquisition unit 120, a calculation unit 130, and a determination unit 140.

[0035] The acquisition unit 120 acquires the SOHf of the FCS 11 from the fuel cell control unit 12. The acquisition unit 120 also acquires the SOHb of the battery 21 from the BMS 22.

[0036] The acquisition unit 120 acquires the requested output (W) from the motor 31.

[0037] The calculation unit 130 calculates Rf by referring to the above formula (1) based on the SOHfa at the start of use of the FCS 11, the SOHfb at the end of its life cycle, and the acquired current SOHfc, which are read from the storage unit 110.

[0038] The calculation unit 130 calculates Rb by referring to the above formula (2) based on the SOHba at the start of use of the battery 21, the SOHbb at the end of its lifespan, and the acquired current SOHbc, which are read from the storage unit 110.

[0039] The determination unit 140 determines whether Rb is less than or equal to a predetermined target value. In this embodiment, the target value is Rf. Note that the target value is sometimes called the "threshold." Therefore, the determination unit 140 determines whether Rb is less than or equal to Rf.

[0040] Figure 5A is a diagram illustrating an example of the control methods for the FCS and battery in this embodiment. Figure 5B is a diagram illustrating another example of the control methods for the FCS and battery in this embodiment. In both Figures 5A and 5B, the horizontal axis represents Time, and the vertical axis represents Power (output). Figures 5A and 5B also show the State of Charge (SOC) decreasing over time.

[0041] The control unit 100 controls the FCS 11 and battery 21 so that when Rb is less than or equal to Rf, the FCS 11 outputs a predetermined first power P1 (W) regardless of the requested output (W), and the battery 21 outputs a second power P2 (W) corresponding to the requested output. When Rb is less than or equal to Rf, as shown in Figure 5A, the FCS 11 outputs a first power P1 which is a predetermined power lower than the power corresponding to the requested output. Note that the first power P1 of the FCS 11 may increase as the SOC of the battery 21 decreases. On the other hand, the battery 21 outputs a second power P2 which is the difference between the requested output and the first power P1. This suppresses the degradation of the FCS 11, which has a larger fluctuation rate (FCS degradation suppression).

[0042] In suppressing FCS degradation, it is desirable to control the output of FCS11 in a region where the power generation efficiency is above a certain level. This is because, when FCS11 is used in a region of high power generation efficiency, less heat is generated by FCS11, thus suppressing degradation due to heat, and also because FCS11 has the characteristic of having maximum power generation efficiency at low output levels. Thus, the first power P1 described above is the power when FCS11 is operating under conditions where its power generation efficiency is higher than a predetermined efficiency (low output power shown by the dashed line in Figure 5A).

[0043] Furthermore, the second power P2 output by the battery 21 is set to a power level corresponding to the difference between the requested output and the first power P1. This makes it possible to cover the difference between the low output of the FCS 11 and the requested output with the output of the battery 21.

[0044] Furthermore, when the State of Charge (SOC) of battery 21 is lower than a predetermined amount, the first power P1 is set higher than the first power P1 in other cases. Figure 5A shows the first power P1' set higher. As the SOC of battery 21 decreases, it is necessary to suppress the output of the second power P2 in order to prevent the SOC of battery 21 from being depleted. Therefore, by setting the first power P1 when the SOC of battery 21 is lower than a predetermined amount higher than the first power P1 in other cases, it becomes possible to cover the difference between the second power P2, which is lower than the power corresponding to the requested output, and the requested output with the output of FCS 11.

[0045] The control unit 100 controls the FCS11 and battery 21 so that when Rb is greater than Rf, the battery 21 outputs a predetermined third power P3 (W) regardless of the requested output, and the FCS11 outputs a fourth power P4 (W) corresponding to the requested output. When Rb is greater than Rf, as shown in Figure 5B, the battery 21 outputs a third power P3, which is a predetermined power lower than the power corresponding to the requested output. Note that the third power P3 of the battery 21 may decrease as the State of Charge (SOC) of the battery 21 decreases. Figure 5B shows the third power P3' that decreases as the SOC decreases. On the other hand, the FCS11 outputs a fourth power P4, which is the difference between the requested output and the third power P3. This suppresses the degradation of the battery 21 with the larger fluctuation rate (battery degradation suppression).

[0046] In suppressing battery degradation, as the State of Charge (SOC) of battery 21 decreases, there is a risk that the output of battery 21 will not be able to cover the difference between the initial output of FCS 11 and the requested output. Therefore, when the SOC of battery 21 decreases, it is possible to suppress the output of battery 21 by increasing the output of FCS 11, thereby preventing the depletion of the SOC of battery 21. As a result, as shown by the thick solid line in Figure 5B, when battery 21 outputs a third power P3 which is a predetermined power lower than the power corresponding to the requested output, the fourth power P4 output by FCS 11 will be the power that is the difference between the requested output and the third power P3, as shown by the dashed line in Figure 5B.

[0047] Next, an example of the operation of the control unit 100 in the embodiment of this disclosure will be described with reference to Figure 6. Figure 6 is a flowchart showing an example of the operation of the control unit 100 in the embodiment of this disclosure. This flow is started by turning on the power switch of the FCV. This flow is repeated at predetermined time intervals.

[0048] First, in step S100, the acquisition unit 120 acquires SOHf from the fuel cell control unit 12. The acquisition unit 120 also acquires SOHb from the BMS 22.

[0049] Next, in step S110, the acquisition unit 120 acquires the output request Pr from the motor 31.

[0050] Next, in step S120, the calculation unit 130 calculates Rf. The calculation unit 130 also calculates Rb.

[0051] Next, in step S130, the determination unit 140 determines whether Rb is less than or equal to Rf. If Rb is less than or equal to Rf (step S130: YES), the process proceeds to step S140. If Rb is greater than Rf (step S130: NO), the process proceeds to step S150.

[0052] In step S140, the control unit 100 controls the FCS 11 and battery 21 so that the FCS 11 outputs a predetermined first power P1 regardless of the requested output, and the battery 21 outputs a second power P2 according to the requested output (FCS degradation suppression). After that, this flow ends.

[0053] In step S150, the control unit 100 controls the FCS11 and battery 21 so that the battery 21 outputs a predetermined third power P3 regardless of the requested output, and the FCS11 outputs a fourth power P4 according to the requested output (battery degradation suppression). After that, this flow ends.

[0054] The output control device (control system 4) in the above embodiment includes an acquisition unit 120 that acquires the Rf (fluctuation rate) of the SOHf of the FCS 11, which outputs power to operate the motor 31 that is the drive source of the vehicle, and the Rb (fluctuation rate) of the SOHb of the battery 21, which outputs power to operate the motor 31, and further acquires information indicating the requested output from the motor 31; and a control unit 100 that controls the battery 21 and FCS 11 so that when Rb is less than or equal to a preset target value (here, Rf), the FCS 11 outputs a predetermined first power P1 regardless of the requested output, and the battery 21 outputs a second power P2 corresponding to the requested output; and when Rb is greater than Rf, the battery 21 outputs a predetermined third power P3 regardless of the requested output, and the FCS 11 outputs a fourth power P4 corresponding to the requested output.

[0055] With the above configuration, the degree of deterioration of the SOH of the FCS11 and battery 21 can be easily compared based on the fluctuation rate of the SOH of the FCS11 and battery 21, making it possible to balance the degradation of the FCS11 and battery 21.

[0056] Furthermore, in the control system 4 of the above embodiment, Rf, which is the rate of change of SOHf of FCS11, is used as information regarding the health of FCS11, and Rf is set as the target value. As a result, it is possible to control the battery 21 and FCS11 respectively based on the determination result of whether Rb is less than or equal to Rf, so that the determination can be made quickly. In turn, it becomes possible to control the battery 21 and FCS11 respectively quickly.

[0057] Furthermore, in the output control device according to the embodiment of this disclosure, information regarding the health of the FCS11 is Rf of the SOHf of the FCS11. Information regarding the health of the battery 21 is Rb of the SOHb of the battery 21. Moreover, Rf and Rb are the ratio of the amount of change in SOH from the start of use to the present time to the total amount of change in SOH that occurs from the start of use to the end of use when the use of the power source ends due to the lifespan of the FCS11 and battery 21, respectively.

[0058] Generally, there is a difference between the total fluctuation amount of the SOH of the FCS11 and the total fluctuation amount of the SOH of the battery 21. Therefore, a difference arises between the rate of degradation of the FCS11 and the rate of degradation of the battery 21. This makes it difficult to relatively monitor the degree of SOH degradation of the FCS11 and the battery 21. In the embodiment of this disclosure, by comparing Rb (rate of change) with Rf (rate of change), it becomes possible to relatively monitor the degree of SOH degradation of the FCS11 and the battery 21, making it easy to balance the degradation of the FCS11 and the battery 21.

[0059] (Variation 1) Next, a modified example 1 of the embodiment of the present disclosure will be described. In the above embodiment, the control unit 100 uses Rf as a target value, compares Rf with Rb, and controls the FCS 11 and battery 21 based on the comparison result. Rf is a value that increases according to the vehicle's driving range. However, the target value in this disclosure is not limited to Rf.

[0060] In Modification 1, the target value is a value that is pre-set to increase according to the cruising range (km), similar to Rf and Rb shown in Figure 3. The relationship between the cruising range and the target value is set based on durability test results, simulations using degradation models, and empirical rules. The target value set in this way is sometimes called the "SOH degradation model line." For example, the target value at the start of power source use is set to 0 (%), and the target value at the end of power source use is set to 100 (%). The memory unit 110 has a table TBL (see Figure 4) that shows the relationship between the cruising range (km) and the target value (%).

[0061] If the target value is fixed without increasing according to the cruising range, a low target value would cause the fluctuation rate Rb of the battery 21's SOHb to remain above the target value, leading to continued operation in the FCS degradation control mode and accelerating the degradation of the battery 21. Conversely, if the target value is high, before reaching a certain cruising range, the fluctuation rates of both the FCS 11 and the battery 21 will be smaller than the target value, making it difficult to switch to an appropriate degradation suppression control mode. In either case, it becomes difficult to solve the problem of balancing the degradation of the FCS 11 and the battery 21 as described above. As described above, by pre-setting the target value to increase according to the cruising range, it becomes possible to balance the degradation of the FCS 11 and the battery 21 along the model line of SOH degradation with respect to cruising range. Furthermore, by setting the target value as a predicted value based on empirical rules, for example, it becomes possible to control both the FCS 11 and the battery 21 so that they reach the predicted lifespan.

[0062] In the modified example 1, the calculation unit 130 calculates a target value based on the cruising range read from the storage unit 110 and the table TBL. The calculation unit 130 calculates Rdf, which is the difference between Rf and the target value. The calculation unit 130 also calculates Rdb, which is the difference between Rb and the target value.

[0063] In the modified example 1, the determination unit 140 determines whether Rdb is greater than 0. It also determines whether Rdf is greater than 0. Furthermore, the determination unit 140 determines whether Rdb is less than Rdf.

[0064] Figure 7A is a diagram showing an example of the control methods for the FCS and battery in Modification Example 1. Figure 7B is a diagram showing another example of the control methods for the FCS and battery in Modification Example 1. Figure 7C is a diagram showing yet another example of the control methods for the FCS and battery in Modification Example 1. In Figures 7A, 7B, and 7C, the horizontal axis represents Time, and the vertical axis represents Power (output). Figures 7A, 7B, and 7C also show the State of Charge (SOC) decreasing over time.

[0065] In Modification 1, the control unit 100 controls the FCS 11 and battery 21 such that when Rdf is greater than 0 and Rdb is greater than 0, the FCS 11 outputs a fifth power P5 (W), which is half the requested output, and the battery 21 outputs a sixth power P6, which is the difference between the requested output and the fifth power P5. In this case, as shown in Figure 7A, the control of the FCS 11 becomes a steady-state output control with a rough load fluctuation period. The control of the battery 21 becomes load-following control. As a result, if the respective fluctuation rates Rf and Rb of the FCS 11 and battery 21 both exceed the target value, neither the degradation of the FCS nor the battery 21 is suppressed (no degradation suppression). The fifth power P5 may increase as the SOC of the battery 21 decreases. In other words, the fifth power P5 may be set higher when the SOC of the battery 21 is lower than a predetermined amount than when it is not.

[0066] The control method described above, which does not suppress degradation, is a control method used when both the FCS11 and the battery 21 have already undergone significant degradation. If the output of one of the power sources of the FCS11 or the battery 21 is suppressed and the output of the other power source of the FCS11 or the battery 21 is actively increased, the degradation of the other power source will progress more rapidly than that of the other power source, making it difficult to balance the degradation of the FCS11 and the battery 21. Therefore, when both the FCS11 and the battery 21 have already undergone significant degradation, the control method without degradation suppression is adopted.

[0067] Furthermore, in the control method without degradation suppression described above, if the State of Charge (SOC) of battery 21 decreases, the output of battery 21 may be suppressed to prevent SOC depletion. This will cause the sixth power P6 to decrease. The fifth power P5 may be increased to cover the difference between the decreasing sixth power P6 and the required output with the output of FCS 11. In other words, the fifth power P5 may increase in accordance with the decrease in the SOC of battery 21.

[0068] The above describes the case where a control method without degradation suppression is performed when Rdb is greater than 0 and Rdf is greater than 0, that is, when both Rb and Rf exceed the target value. Next, we will describe the control method when Rdb is not greater than 0, or when Rdf is not greater than 0, that is, when at least one of Rb or Rf does not exceed the target value.

[0069] In Modification 1, the control unit 100 controls the FCS 11 and battery 21 so that, when at least one of Rb and Rf does not exceed the target value and Rdb is less than or equal to Rdf, the FCS 11 outputs a predetermined first power P1 (W) regardless of the requested output, and the battery 21 outputs a second power P2 (W) corresponding to the requested output. When Rdb is less than or equal to Rdf, as shown in Figure 7B, the FCS 11 outputs a first power P1 which is a predetermined power lower than the power corresponding to the requested output. Note that the first power P1 of the FCS 11 may increase as the SOC of the battery 21 decreases. On the other hand, the battery 21 outputs a second power P2 which is the difference between the requested output and the first power P1. As a result, the fluctuation rates Rf and Rb of the FCS 11 and battery 21 are compared with the target values, and the degradation of the FCS 11 with the smaller margin relative to the target values ​​of fluctuation rates Rf and Rb is suppressed (FCS degradation suppression).

[0070] As described above, in the FCS degradation suppression in Modification 1, the determination method (control conditions) differs from that of the FCS degradation suppression in the above embodiment. However, the control method may be the same as that of the FCS degradation suppression in the above embodiment.

[0071] In Modification 1, the control unit 100 controls the FCS 11 and the battery 21 so that when Rdb is greater than Rdf, the battery 21 outputs a predetermined third power P3 (W) regardless of the requested output, and the FCS 11 outputs a fourth power P4 (W) corresponding to the requested output. When Rdb is greater than Rdf, as shown in Figure 7C, the battery 21 outputs a third power P3, which is a predetermined power lower than the power corresponding to the requested output. Note that the third power P3 may decrease as the SOC of the battery 21 decreases. On the other hand, the FCS 11 outputs a fourth power P4, which is the difference between the requested output and the third power P3. This suppresses the degradation of the battery 21 with less margin (battery degradation suppression).

[0072] As described above, in the battery degradation suppression in Modification 1, the determination method (control conditions) differs from that of the battery degradation control in the above embodiment. However, the control method may be the same as that of the battery degradation suppression in the above embodiment.

[0073] Next, an example of the operation of the control unit 100 in Modification Example 1 will be described with reference to Figure 8. Figure 8 is a flowchart showing an example of the operation of the control unit 100 in Modification Example 1. This flow is started by turning on the power switch of the FCV. This flow is repeated at predetermined time intervals.

[0074] First, in step S200, the acquisition unit 120 acquires SOHf from the fuel cell control unit 12. The acquisition unit 120 also acquires SOHb from the BMS 22.

[0075] Next, in step S210, the acquisition unit 120 acquires the output request Pr from the motor 31.

[0076] Next, in step S220, the calculation unit 130 calculates Rf. The calculation unit 130 also calculates Rb.

[0077] Next, in step S230, the calculation unit 130 calculates a target value based on the cruising range and table TBL read from the storage unit 110.

[0078] Next, in step S240, the calculation unit 130 calculates Rdf, which is the difference between Rf and the target value. The calculation unit 130 also calculates Rdb, which is the difference between Rb and the target value.

[0079] Next, in step S250, the determination unit 140 determines whether Rdb is greater than 0 and Rdf is greater than 0. If Rdb is greater than 0 and Rdf is greater than 0 (step S270: YES), the process proceeds to step S260. If Rdb is not greater than 0, or Rdf is not greater than 0 (step S250: NO), the process proceeds to step S270.

[0080] In step S260, the control unit 100 controls the FCS 11 and battery 21 so that the FCS 11 outputs a fifth power P5 (W) which is half the requested output, and the battery 21 outputs a sixth power P6 which is the difference between the requested output and the fifth power P5 (without degradation suppression). After that, this flow ends.

[0081] In step S270, the determination unit 140 determines whether Rdb is less than or equal to Rdf. If Rdb is less than or equal to Rdf (step S270: YES), the process proceeds to step S280. If Rdb is not less than or equal to Rdf (step S270: NO), the process proceeds to step S290.

[0082] In step S280, the control unit 100 controls the FCS 11 and battery 21 so that the FCS 11 outputs a predetermined first power P1 regardless of the requested output, and the battery 21 outputs a second power P2 according to the requested output (FCS degradation suppression). After that, this flow ends.

[0083] In step S290, the control unit 100 controls the FCS11 and battery 21 so that the battery 21 outputs a predetermined third power P3 regardless of the requested output, and the FCS11 outputs a fourth power P4 according to the requested output (battery degradation suppression). After that, this flow ends.

[0084] (Modification 2) Next, we will explain the second modified example. In the above modified example 1, the SOH degradation model line is used as the target value, the difference Rdb between Rd and the target value and the difference Rdf between Rf and the target value are calculated, Rdb and Rdf are compared, and the FCS11 and battery21 are controlled based on the comparison result.

[0085] On the other hand, in Modification 2, the use of the SOH degradation model line as the target value is the same as in Modification 1, and the target value is a value that is pre-set to increase according to the cruising range (km), similar to Rf and Rb shown in Figure 3. However, in Modification 2, the FCS11 and battery21 are controlled based on the results of comparing Rd with the target value and the results of comparing Rf with the target value.

[0086] As described above, the SOH degradation model line is used as the target value in the modified example 2. The memory unit 110 has a table TBL (see Figure 4) that shows the relationship between the cruising range (km) and the target value (%).

[0087] In the modified example 2, the calculation unit 130 calculates a target value based on the cruising range read from the storage unit 110 and the table TBL (see Figure 4).

[0088] In the modified example 2, the determination unit 140 determines whether Rb is greater than the target value. The determination unit 140 also determines whether Rf is greater than the target value.

[0089] Figure 9A shows an example of the control methods for the FCS and battery in Modification Example 2. Figure 9B shows another example of the control methods for the FCS and battery in Modification Example 2. Figure 9C shows yet another example of the control methods for the FCS and battery in Modification Example 2. In Figures 9A, 9B, and 9C, the horizontal axis represents Time, and the vertical axis represents Power (output). Figures 9A, 9B, and 9C also show the State of Charge (SOC) decreasing over time.

[0090] In Modified Example 2, the control unit 100 controls the FCS 11 and battery 21 so that when Rb is below the target value, the FCS 11 outputs a predetermined first power P1 (W) regardless of the requested output, and the battery 21 outputs a second power P2 (W) corresponding to the requested output. In this case, as shown in Figure 9A, the FCS 11 outputs a first power P1 which is a predetermined power lower than the power corresponding to the requested output. Note that the first power P1 of the FCS 11 may increase as the SOC of the battery 21 decreases. On the other hand, the battery 21 outputs a second power P2 which is the difference between the requested output and the first power P1. This suppresses the degradation of the FCS 11 (FCS degradation suppression). In the FCS degradation suppression in Modified Example 2, the determination method (control conditions) is different from the FCS degradation suppression in Modified Example 1. Note that the control method may be the same as the FCS degradation suppression in Modified Example 1.

[0091] In Modification 2, the control unit 100 controls the battery 21 and the battery 21 so that when Rb is greater than the target value and Rf is less than or equal to the target value, the battery 21 outputs a predetermined third power P3 (W) regardless of the requested output, and the FCS 11 outputs a fourth power P4 (W) corresponding to the requested output. In this case, as shown in Figure 9B, the battery 21 outputs a third power P3, which is a predetermined power lower than the power corresponding to the requested output. Note that the third power P3 may decrease as the SOC of the battery 21 decreases. On the other hand, the FCS 11 outputs a fourth power P4, which is the difference between the requested output and the third power P3. This suppresses the degradation of the battery 21 (battery degradation suppression). In the battery degradation suppression in Modification 2, the determination method (control conditions) is different from the battery degradation suppression in Modification 1. Note that the control method may be the same as the battery degradation suppression in Modification 1.

[0092] In Modification 2, the control unit 100 controls the FCS 11 and battery 21 such that when Rb is greater than the target value and Rf is greater than the target value, the FCS 11 outputs a fifth power P5 which is half the output of the requested output, and the battery 21 outputs a sixth power P6 corresponding to the difference between the requested output and the fifth power P5. In this case, as shown in Figure 9C, the control of the FCS 11 becomes a steady-state output control with a rough load fluctuation period. The fifth power P5 may increase as the SOC of the battery 21 decreases. The control of the battery 21 becomes load-following control. As a result, degradation of neither the FCS nor the battery 21 is suppressed (no degradation suppression). In Modification 2 without degradation control, the determination method (control conditions) is different from that in Modification 1 without degradation control. The control method may be the same as in Modification 1 without degradation control.

[0093] Next, an example of the operation of the control unit 100 in Modification 2 will be described with reference to Figure 10. Figure 10 is a flowchart showing an example of the operation of the control unit 100 in Modification 2. This flow is started by turning on the power switch of the FCV. This flow is repeated at predetermined time intervals.

[0094] First, in step S300, the acquisition unit 120 acquires SOHf from the fuel cell control unit 12. The acquisition unit 120 also acquires SOHb from the BMS 22.

[0095] Next, in step S310, the acquisition unit 120 acquires the output request Pr from the motor 31.

[0096] Next, in step S320, the calculation unit 130 calculates Rf. The calculation unit 130 also calculates Rb.

[0097] Next, in step S330, the calculation unit 130 calculates a target value based on the cruising range and table TBL read from the storage unit 110.

[0098] Next, in step S340, the determination unit 140 determines whether Rb is less than or equal to the target value. If Rb is less than or equal to the target value (step S340: YES), the process proceeds to step S350. If Rb is greater than the target value (step S340: NO), the process proceeds to step S360.

[0099] Next, in step S350, the control unit 100 controls the FCS 11 and the battery 21 so that the FCS 11 outputs a predetermined first power P1 regardless of the requested output, and the battery 21 outputs a second power P2 according to the requested output (FCS degradation suppression).

[0100] Next, in step S360, the determination unit 140 determines whether Rf is less than or equal to the target value. If Rf is less than or equal to the target value (step S360: YES), the process proceeds to step S370. If Rf is not less than or equal to the target value (step S360: NO), the process proceeds to step S380.

[0101] Next, in step S370, the control unit 100 controls the FCS11 and the battery 21 so that the battery 21 outputs a predetermined third power P3 regardless of the requested output, and the FCS11 outputs a fourth power P4 according to the requested output (battery degradation suppression).

[0102] Next, in step S380, the control unit 100 controls the FCS 11 and the battery 21 so that the FCS 11 outputs a fifth power P5 (W) which is half the output of the requested output, and the battery 21 outputs a sixth power P6 which is the difference between the requested output and the fifth power P5.

[0103] In the control system 4 (output control device) in the above embodiment, the target value was set to Rf (the rate of change of SOH of the FCS11), and it was determined whether Rf was greater than or equal to Rb. Based on the determination result, the outputs of the FCS11 and the battery 21 were controlled. In the modified examples 1 and 2, the target value was set to a value that increases according to the cruising range (a value based on the SOH degradation model), and the outputs of the FCS11 and the battery 21 were controlled based on Rf, Rb, and the target value.

[0104] However, the target value in this disclosure may be Rb. In this case, it may be determined whether Rf is less than or equal to Rb, and the outputs of the FCS11 and battery21 may be controlled based on the determination result.

[0105] In the above modified example 2, a value based on one SOH degradation model was shown as the target value, but the target value in this disclosure is not limited to one. In particular, as a control condition (determination method) without degradation suppression, two or more different target values ​​may be set, for example, a first target value compared with Rb and a second target value compared with Rf. Alternatively, for example, two or more models selected by the user from among a plurality of SOH degradation models set according to the usage of the FCV may be used as the target values.

[0106] Furthermore, the embodiments described above are merely examples of how the Disclosure may be implemented, and the technical scope of the Disclosure should not be limited by them. In other words, the Disclosure can be implemented in various ways without departing from its essence or its main features. [Industrial applicability]

[0107] This disclosure is particularly useful for FCVs equipped with an output control device that is required to balance the degradation of the battery and the fuel cell. [Explanation of Symbols]

[0108] 1. Fuel cell system 2 Battery System 3. Electric PF System 4. Control System (Output Control Device) 5 Hydrogen tanks 6. Air filter 7 wheels 11. FCS (Fuel Cell Stack) 12 Fuel cell control unit 21 batteries 22 BMS 31 Motor 32 Inverters 33 Gearbox 100 Control Unit 110 Storage section 120 Acquisition Department 130 Calculation Unit 140 Judgment section

Claims

1. An acquisition unit that acquires information regarding the health of a fuel cell that outputs power to operate a motor that serves as the drive source for a vehicle, and information regarding the health of a battery that outputs power to operate the motor, and further acquires information indicating the requested output from the motor, A control unit controls the battery and the fuel cell so that, if the information regarding the health of the battery is below a preset target value, the fuel cell outputs a predetermined first power regardless of the requested output, and the battery outputs a second power corresponding to the requested output; and if the information regarding the health of the battery is greater than the target value, the battery outputs a predetermined third power regardless of the requested output, and the fuel cell outputs a fourth power corresponding to the requested output. Equipped with, Output control device.

2. The aforementioned target value is information regarding the health of the fuel cell. The output control device according to claim 1.

3. The aforementioned target value is a value that is set in advance to increase according to the cruising range of the vehicle. The output control device according to claim 1.

4. The first power is the power generated when the fuel cell operates under conditions where its power generation efficiency is higher than a predetermined efficiency. The output control device according to claim 1.

5. When the remaining capacity of the battery is lower than a predetermined amount, the first power is higher than the first power when it is not lower. The output control device according to claim 1.

6. The second power is power corresponding to the difference between the requested output and the first power. The output control device according to claim 1.

7. The third power when the remaining capacity of the battery is lower than a predetermined amount is lower than the third power when it is not lower. The output control device according to claim 1.

8. The fourth power is the power corresponding to the difference between the requested output and the third power. The output control device according to claim 1.

9. If the information regarding the health of the battery exceeds a predetermined first target value, and the information regarding the health of the fuel cell exceeds a predetermined second target value, the battery and the fuel cell are controlled such that the fuel cell outputs a fifth power corresponding to the requested output, and the battery outputs a sixth power corresponding to the difference between the requested output and the fifth power. The output control device according to claim 1.

10. The fifth power when the remaining capacity of the battery is lower than a predetermined amount is higher than the fifth power when it is not lower. The output control device according to claim 9.

11. An acquisition unit that acquires information regarding the health of a fuel cell that outputs power to operate a motor that serves as the drive source for a vehicle, and information regarding the health of a battery that outputs power to operate the motor, and further acquires information indicating the requested output from the motor, A control unit that controls the power output from the battery and the fuel cell, respectively, based on information regarding the health of the fuel cell, information regarding the health of the battery, and the requested output. Equipped with, Output control device.

12. The information relating to the health of the fuel cell is the rate of change in the health of the fuel cell as a power source. The information relating to the health of the battery is the rate of change in the health of the battery as a power source. The rate of change in the soundness is the ratio of the amount of change in soundness from the start of use to the present to the total amount of change in soundness from the start of use to the end of use when the use of the power source ends due to the end of its lifespan. The output control device according to claim 1 or 11.

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