Fuel cell vehicle

Abstract

A fuel cell vehicle disclosed in the present specification is provided with a fuel cell, a storage battery capable of being recharged, and a controller that controls the fuel cell. The controller performs a reset process of charging the storage battery to a full voltage corresponding to a full charge by output power of the fuel cell outside a region decided in advance.

Description

Technical Field

[0001] The technology disclosed in this specification relates to fuel cell vehicles equipped with fuel cells and batteries. Background Technology

[0002] Fuel cell vehicles consist of a fuel cell and a battery that supply power to the motor used for driving. If the remaining capacity of the battery exceeds its full charge capacity but falls below a specified lower limit, degradation accelerates. Therefore, managing the remaining capacity is crucial when using a battery. The remaining capacity of a battery is also known as SOC (State of Charge). Remaining capacity (or SOC) can be expressed as the electrical capacity stored in the battery (measured in Ah), or it can be expressed as the ratio of the current capacity to the capacity at full charge (charge rate).

[0003] There are two known methods for estimating the remaining capacity of a battery. One is the method of estimating the remaining capacity based on the battery's open-circuit voltage (OCV method). The other is the method of accumulating the current flowing into and out of the battery (current accumulation method). The OCV method is used when the relationship between the battery's open-circuit voltage (OCV) and remaining capacity is roughly proportional, and when the remaining capacity changes relatively significantly with respect to changes in the open-circuit voltage. On the other hand, certain types of batteries, such as lithium iron phosphate batteries, have a remaining capacity range (also known as the plateau region) where the open-circuit voltage does not change much with respect to changes in remaining capacity. For the OCV method, the estimation error of the remaining capacity becomes larger. The current accumulation method is used for such batteries (e.g., International Publication No. 2018 / 181489).

[0004] If the current accumulation method is used for an extended period, accumulated errors will accumulate, thus increasing the error in estimating the remaining capacity. As a method to correct the estimation error of the current accumulation method, a known method is to charge the battery until its output voltage reaches a voltage equivalent to a full charge (International Publication No. 2018 / 181489). Hereinafter, for ease of explanation, the battery voltage equivalent to a full charge will be referred to as the full voltage. The battery capacity at full voltage (full capacity) is also known.

[0005] The battery is charged until its output voltage reaches full voltage, and this is taken as the initial value of the remaining capacity (or charging rate of 100%). Then, using a current accumulation method, the accumulated value of the current discharged from the battery is subtracted from the initial value of the remaining capacity (full capacity) to calculate the current remaining capacity. For ease of explanation, the process of charging the battery until its output voltage reaches full voltage (including setting the initial value of the remaining capacity (or charging rate of 100%)) will be referred to as the reset process. Furthermore, for ease of explanation, the process of "charging the battery until its output voltage reaches full voltage" may be simply expressed as "charging the battery to full voltage".

[0006] As described above, a fuel cell vehicle possesses a fuel cell and a battery. Therefore, the fuel cell can be used to charge and reset the battery. A corresponding electrical force is required to charge the battery to full voltage. If a large electrical force is generated in the fuel cell, a large amount of water (generated through the chemical reaction of hydrogen and oxygen) is also produced. Depending on the location of the fuel cell vehicle, there may be situations where drainage is undesirable. This specification provides a technique for avoiding large amounts of drainage in undesirable locations in a fuel cell vehicle that uses a fuel cell to reset the battery. Summary of the Invention

[0007] The fuel cell vehicle according to the first aspect of this disclosure includes a fuel cell, a rechargeable battery, and a controller for controlling the fuel cell. Outside a predetermined area, the controller performs a reset process to charge the battery to a full voltage equivalent to a full charge using the output power of the fuel cell. Whether the vehicle is in the predetermined area can be determined, for example, using GPS. In the fuel cell vehicle disclosed in this specification, the reset process is not performed in the predetermined area (an area where large amounts of drainage are not desired).

[0008] When the battery is charged to full voltage, the fuel cell generates a large amount of electricity, which may increase the noise of auxiliary equipment such as fans. Based on the fuel cell vehicle according to the first aspect of this disclosure, the controller can also disable reset processing when the speed is below a specified threshold. Furthermore, based on the fuel cell vehicle according to the first aspect of this disclosure, the controller can also disable reset processing when the vibration or noise of the fuel cell vehicle is below a specified noise threshold. Alternatively, reset processing may be performed only when the fuel cell vehicle speed is high, or when the vibration or noise of the fuel cell vehicle is high, thereby mixing the noise generated by the reset processing with the vehicle's noise.

[0009] It can also be configured such that, based on the fuel cell vehicle according to the first aspect of this disclosure, the controller begins reset processing if certain conditions are met. For example, it can also be configured such that, if at least one of the following conditions is met: (1) after the main switch of the fuel cell vehicle is turned on; (2) after the main switch is turned on again after a predetermined placement time has elapsed during the period when the main switch is off; (3) the time for calculating the remaining capacity of the battery based on the cumulative current value relative to the current flowing in and out of the battery exceeds a predetermined duration, the controller begins reset processing. Reset processing can be performed before the error of the cumulative current value becomes large.

[0010] The fuel cell vehicle according to the first aspect of this disclosure may also have a driving motor that receives power from at least one of the fuel cell and the battery, and the battery may also store the regenerative power of the motor. During the reset process, there is a concern that charging the battery to full voltage may result in insufficient capacity to store regenerative power. This specification also provides a technique that achieves both reset processing and regenerative power storage.

[0011] The fuel cell vehicle according to the first aspect of this disclosure may also include a driving motor that receives power from at least one of the aforementioned fuel cell and the aforementioned battery. The battery may also include a first battery and a second battery capable of storing regenerated power, and the fuel cell may also include a first fuel cell and a second fuel cell. It may also be configured such that, when the remaining capacity of the second battery is lower than a predetermined remaining capacity threshold, the controller connects the second battery and the second fuel cell to the motor, disconnects the first battery and the first fuel cell from the motor, and uses the first fuel cell to perform a reset process on the first battery. During the reset process of the first battery using the first fuel cell, regenerated power can be stored in the second battery.

[0012] The controller can also perform a reset of the second battery following the reset of the first battery. Alternatively, based on the fuel cell vehicle according to the first aspect of this disclosure, after completing the reset of the first battery, the controller connects the first battery and the first fuel cell to the motor, and disconnects the second battery and the second fuel cell from the motor. If the remaining capacity of the first battery is lower than a predetermined remaining capacity threshold, the second fuel cell is used to perform a reset of the second battery. In this way, regenerated power can be accumulated in the first battery during the reset of the second battery. Furthermore, the controller can also be configured to connect the first battery and the first fuel cell to the motor after completing the reset of the first battery, and disconnect the second battery and the second fuel cell from the motor, using the motor (or other electrical equipment) to consume the remaining capacity of the first battery.

[0013] The fuel cell vehicle according to the first aspect of this disclosure may also include a first relay and a second relay. The first battery and the first fuel cell may also be connected to the motor via the first relay, and the second battery and the second fuel cell may also be connected to the motor via the second relay. The controller may also control the opening and closing of the first relay and the second relay.

[0014] The fuel cell vehicle according to the first aspect of this disclosure may also have a switch that disables the aforementioned reset process. The switch may also be connected to the controller, and when the switch is turned off, the controller may not perform the aforementioned reset process.

[0015] Furthermore, the remaining capacity threshold can be adjusted based on the region. For example, in areas where brakes are frequently used, a larger amount of regenerative power can be expected. In such cases, the remaining capacity threshold can be set lower, allowing for the accumulation of more regenerative power. Conversely, in areas with fewer traffic lights, a larger amount of regenerative power cannot be expected, so the remaining capacity threshold can be set higher.

[0016] The detailed description of the technology disclosed in this specification and further improvements are described in the following "Detailed Description".

[0017] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements. Attached Figure Description

[0018] Figure 1 This is a block diagram of the fuel cell vehicle of the first embodiment.

[0019] Figure 2 This is a flowchart for determining whether to perform a reset process.

[0020] Figure 3 This is a flowchart of the reset process.

[0021] Figure 4 It continues Figure 3 The flowchart shows the reset process and the processes performed after the reset process.

[0022] Figure 5 This is a block diagram of the fuel cell vehicle of the second embodiment.

[0023] Figure 6 This is a block diagram of a modified example of the fuel cell vehicle of the second embodiment. Detailed Implementation

[0024] (First Embodiment) In Figure 1The diagram shows a block diagram of a fuel cell vehicle 2 according to the first embodiment. The fuel cell vehicle 2 drives the wheels 6 by an electric motor (motor 4) for driving. The output shaft of the motor 4 is connected to the wheels 6 via a differential gear 5.

[0025] For ease of explanation, "fuel cell" may be referred to as "FC" in the following text. "Fuel cell 12" is referred to as "FC12". In the diagram, "BT", "FC", "INV", and "M" refer to the battery, fuel cell, inverter, and motor, respectively.

[0026] The fuel cell vehicle 2 is equipped with a battery 11 and an FC12 as power sources. The output terminals of the battery 11 and the FC12 are connected to an inverter 3. The inverter 3 converts the DC power supplied from at least one of the battery 11 and the FC12 into AC power suitable for driving the motor 4.

[0027] An auxiliary unit 13 is attached to the FC12 to drive it. The auxiliary unit 13 is a collective term for the group of equipment required for the FC12 to generate electricity, including fans, pumps, valves, converters, coolers, etc.

[0028] The fuel cell vehicle 2 is a truck equipped with a refrigeration unit 40, capable of transporting large quantities of refrigerated goods. The power to operate the refrigeration unit 40 is also supplied from either the battery 11 or the FC12. Since the refrigeration unit 40 consumes a large amount of power, the battery 11 is of high capacity, and the FC12 is of high output.

[0029] Figure 1 The dashed lines represent signal lines. FC12 and auxiliary unit 13 are controlled by controller 30. Motor 4 is controlled by controller 30 via inverter 3. Refrigeration unit 40 is also controlled by controller 30.

[0030] A temperature sensor 41 is provided in the refrigerator 40, and the measured value of the temperature sensor 41 is sent to the controller 30. The temperature sensor 41 measures the temperature in the refrigerator 40. The controller 30 controls the refrigerator 40 so that the measured value of the temperature sensor 41 (i.e., the temperature in the refrigerator 40) is maintained at a predetermined temperature below the freezing point.

[0031] A voltage sensor 14 and a current sensor 16 are provided at the output terminal of the battery 11. The voltage sensor 14 measures the output voltage of the battery 11, and the current sensor 16 measures the current flowing into and out of the battery 11. A voltage sensor 15 and a current sensor 17 are provided at the output terminal of the FC12. The voltage sensor 15 measures the output voltage of the FC12, and the current sensor 17 measures the current output from the FC12. The measured values ​​of the voltage sensors 14 and 15, and the current sensors 16 and 17 are sent to the controller 30.

[0032] The controller 30 uses measurements from voltage sensor 15 and current sensor 17 to control FC12 and auxiliary unit 13, so that the output of FC12 follows the target output. Additionally, the controller 30 uses measurements from voltage sensor 14 and current sensor 16 to monitor the state of battery 11.

[0033] The fuel cell vehicle 2 is equipped with a vehicle speed sensor 7 that measures vehicle speed, and the measurement value of the vehicle speed sensor 7 is also sent to the controller 30. The fuel cell vehicle 2 is equipped with an accelerator sensor 31 that measures the opening of the accelerator pedal and a brake sensor 32 that measures the opening of the brake pedal. The controller 30 determines the output requested to the motor 4 (requested output) based on the vehicle speed and the accelerator pedal opening. The controller 30 controls the FC12, auxiliary motor 13, and inverter 3 so that the output of the motor 4 follows the requested output. In addition, the controller 30 determines the target output of the FC12 based on the requested output and the state of the battery 11.

[0034] After the brake pedal is depressed, the controller 30 determines the target braking force based on the vehicle speed and brake pedal opening. A portion of the target braking force is supplied by the reverse drive of the motor 4. The remaining portion of the target braking force is supplied by the mechanical brake 8. The controller 30 controls the inverter 3 to ensure that the motor 4 exerts the prescribed braking force. Electricity is generated through the reverse drive of the motor 4. In other words, the motor 4 generates electricity using the vehicle's inertial energy while applying braking force to the vehicle. The electricity obtained through the reverse drive of the driving motor 4 is called regenerative electricity. The regenerative electricity (AC) generated by the motor 4 is converted to DC power by the inverter 3 and then supplied to the battery 11. That is, the regenerative electricity is stored in the battery 11. The controller 30 controls the mechanical brake 8 so that the sum of the braking force generated by the reverse drive of the motor 4 and the braking force generated by the mechanical brake 8 matches the target braking force.

[0035] Battery 11 is rechargeable and is typically a lithium iron phosphate battery. Battery 11 and FC12 are connected in parallel to the DC terminal of inverter 3. The response frequency of FC12 is lower than the response frequency requested by motor 4. The output response frequency of battery 11 is higher than the response frequencies of FC12 and motor 4. When the requested output of motor 4 increases sharply, the insufficient portion of the requested output is supplemented by the output of battery 11 during the period until the output of FC12 increases. In addition, when the requested output of motor 4 decreases sharply, the excess power of FC12 is stored in battery 11. As described above, regenerated power is also stored in battery 11. The excess and insufficient portions of FC12's output are borne by battery 11 relative to the sharp changes in power consumption accompanying the start and stop of refrigerator 40.

[0036] For battery 11, overcharging and an extreme decrease in remaining capacity will exacerbate its degradation. Therefore, it is necessary to maintain the remaining capacity of battery 11 within an appropriate range (suitable range). Controller 30 accumulates the current flowing into and out of battery 11 and uses the accumulated current value to determine the increase or decrease in the remaining capacity of battery 11. The method of inferring the remaining capacity of the battery based on the accumulated current value is called the current accumulation method. In order to use the current accumulation method, an initial value of remaining capacity as a reference is required. Generally, when the battery's output voltage is equal to the voltage equivalent to a full charge (full voltage), a known relationship between voltage and remaining capacity (full capacity) holds. Therefore, controller 30 charges battery 11 until the output voltage of battery 11 reaches full voltage and sets the full capacity as the remaining capacity of battery 11 at this time (initial value of remaining capacity). This process is called reset process. After the reset process, controller 30 accumulates the current flowing into and out of battery 11 and subtracts the accumulated current value from the initial value of remaining capacity (full capacity) set at the time of reset to infer the constantly changing remaining capacity. Here, the current output from battery 11 is set to a positive value, and the current supplied to battery 11 is set to a negative value. If current is supplied to battery 11, the estimated value of the remaining capacity increases.

[0037] Furthermore, as described above, there are cases where "charging battery 11 until its output voltage reaches full voltage" is simply expressed as "charging battery 11 to full voltage." Full voltage is equivalent to the voltage at which battery 11 is fully charged, and it is predetermined.

[0038] If the remaining capacity approaches the lower limit of the suitable range, the controller 30 increases the output of FC12 to charge the battery 11, thereby increasing the remaining capacity. Conversely, if the remaining capacity approaches the upper limit of the suitable range, the controller 30 decreases the output of FC12, supplying power to the motor 4 and the refrigerator 40 via the battery 11. As a result, the remaining capacity of the battery 11 decreases.

[0039] If the current accumulation method is used continuously for a long time, accumulated errors will accumulate, and the accuracy of the remaining capacity estimation will decrease. Therefore, the controller 30 periodically performs a reset process to eliminate accumulated errors.

[0040] The following conditions are used as the trigger (starting condition) for initiating the reset process: (1) Immediately after the main switch of the fuel cell vehicle 2 is turned on. (2) Immediately after the main switch is turned on again after a predetermined placement time has elapsed during the period when the main switch is off. (3) When the time for processing the remaining capacity estimation based on the current accumulation value exceeds a predetermined duration. (4) When the driving distance of the fuel cell vehicle 2 exceeds a predetermined distance threshold. All of the above starting conditions (1) to (4) may be used, or only any one of the above starting conditions may be used. The controller 30 uses at least one of the above starting conditions (1) to (4) as the trigger for the reset process.

[0041] Furthermore, the fuel cell vehicle 2 does not perform a reset process in a specific area. That is, outside of a predetermined area, the controller 30 performs a reset process to charge the battery 11 to a full voltage equivalent to a full charge using the output power of the FC12. For ease of explanation, the predetermined area is referred to as a prohibited area. A prohibited area is, for example, a place where goods are loaded and unloaded. During the reset process, the battery 11 is charged to a full voltage using the output of the FC12. This charging requires a corresponding amount of electricity, and if the FC12 generates the corresponding amount of electricity, a large amount of water (water produced through the reaction of oxygen and hydrogen) is generated. In particular, the fuel cell vehicle 2 is equipped with a refrigeration unit 40, and therefore carries a large battery 11. If the large battery 11 is charged to a full voltage, a large amount of water is generated.

[0042] Fuel cell vehicle 2 does not perform reset procedures in areas where significant drainage is undesirable. The flowchart for determining whether to perform a reset procedure is as follows: Figure 2 As shown. If the start condition adopted by controller 30 is met, then start. Figure 2 The processing.

[0043] The prohibited area is defined as a zone where excessive drainage is not desired. A storage device 34 is connected to the controller 30, and the storage device 34 stores information about the prohibited area (prohibited area map). Additionally, the fuel cell vehicle 2 is equipped with a GPS receiver 33, which can determine the current location of the fuel cell vehicle 2. Figure 2 (Step S2). The controller 30 compares the current position obtained from the GPS receiver 33 with the prohibited area map stored in the storage device 34 to determine whether the current position of the fuel cell vehicle 2 is within the prohibited area (steps S3, S4). If the above-mentioned starting conditions are met and the current position of the fuel cell vehicle 2 is outside the prohibited area (step S4: Yes), the controller 30 checks other conditions for starting the reset process (steps S5, S6).

[0044] The controller 30 may also disable the reset process when the vehicle speed is below a specified threshold (step S5: No). Alternatively, the controller 30 may also disable the reset process when the vibration or noise of the fuel cell vehicle 2 is below a specified noise threshold (step S6: No). The vehicle speed can be obtained from the vehicle speed sensor 7. In addition, the fuel cell vehicle 2 is equipped with a noise sensor 35, which measures the magnitude of the noise or vibration of the fuel cell vehicle 2. The controller 30 compares the measured value of the noise sensor 35 with the noise threshold, and disables the reset process when the measured value is below the noise threshold (step S6: No). Furthermore, the noise of the fuel cell vehicle 2 may also include radio noise.

[0045] If the vehicle is outside the prohibited area (step S4: Yes), the vehicle speed exceeds the vehicle speed threshold (step S5: Yes), and the noise or vibration of the fuel cell vehicle 2 exceeds the noise threshold (step S6: Yes), the controller 30 performs a reset process (step S7). If any one of the conditions is not met, the controller 30 does not perform a reset process. Furthermore, the branch judgment processes in steps S5 and S6 are optional, preferably present in the fuel cell vehicle 2, but may not be present.

[0046] Furthermore, during the period from the trigger of the reset process to the start of the reset process, the controller 30 treats the target output of FC12 as the requested output of the motor 4. That is, by supplying the requested power to the motor 4 through FC12 as much as possible, the decrease in the remaining capacity of the battery 11 is suppressed. However, in cases such as when the requested output of the motor 4 increases sharply, power is supplied from the battery 11 to the motor 4.

[0047] Outside of the period from the generation of the trigger to the end of the reset process, the controller 30 sets the target output of FC12 to the value obtained by adding the remaining capacity adjustment amount of the battery 11 to the requested output of the motor 4. The remaining capacity adjustment amount is set to the power required to maintain the remaining capacity of the battery 11 near the target capacity. The target capacity (the target value of the remaining capacity of the battery 11) is set, for example, to the middle value of a suitable range of the remaining capacity of the battery 11. Furthermore, if expressed in terms of charging rate, an example of a suitable range is between 40% and 60%.

[0048] exist Figure 3 The flowchart of the reset process is shown in the figure. Figure 4 The flowchart shows the reset process and subsequent processing. Furthermore, Figure 4 The flowchart is Figure 3The following is a continuation of the flowchart. Controller 30 increases the output of FC12 to charge battery 11 to full voltage. Controller 30 sets the target output of FC12 in the reset process to the value obtained by adding the maximum allowed battery power to the requested output of motor 4 (step S12). The maximum allowed battery power refers to the maximum allowable power that can be supplied to battery 11. By setting the power supplied to battery 11 to the maximum allowed battery power, battery 11 can be charged as early as possible in the reset process.

[0049] However, when the requested output of motor 4 increases sharply, a portion of the predetermined power used for charging battery 11 is supplied to motor 4. When the output of FC12 is less than the requested output, power is output from battery 11. In other words, fulfilling the requested output of motor 4 takes priority over charging battery 11.

[0050] Additionally, when regenerative power is generated during the reset process, the controller 30 sets the target output of FC12 to the value obtained by subtracting the regenerative power from the maximum allowable battery power. The regenerative power is also used to charge the battery 11 to full voltage, but by reducing the target output of FC12, power exceeding the maximum allowable battery power is prevented from flowing in the battery 11.

[0051] The controller 30 continues charging until the output voltage of the battery 11 reaches full voltage (step S16). However, if the vehicle enters a prohibited area while charging to full voltage (step S13: No), if the vehicle speed falls below the vehicle speed threshold (step S14: No), or if the vehicle noise falls below the noise threshold (step S15: No), the controller 30 interrupts the reset process.

[0052] During the interruption of the reset process, the target output of FC12 is used as the requested output of motor 4. That is, by supplying the requested power to motor 4 through FC12 as much as possible, the decrease in the remaining capacity of battery 11 is suppressed. However, in cases such as when the requested output of motor 4 increases sharply, power is supplied from battery 11 to motor 4. Furthermore, steps S14 to S15 are optional and preferably used, but they can also be omitted.

[0053] If the output voltage of battery 11 reaches full voltage (step S16: Yes), then controller 30 sets the full capacity as the initial value of the remaining capacity of battery 11. Figure 4 (Step S21). Afterwards, the controller 30 subtracts the cumulative value of the current flowing in and out of the battery 11 from the initial value of the remaining capacity to infer the current of the battery 11.

[0054] As described above, when no reset is performed, the controller 30 sets the target output of FC12 to the value obtained by adding the remaining capacity adjustment of the battery 11 to the requested output of the motor 4.

[0055] When the battery 11 is charged to full voltage during the reset process, its remaining capacity becomes full. Therefore, after charging the battery 11 to full voltage, the controller 30 sets a relatively large negative value as the remaining capacity adjustment amount further added to the target output of FC12. In other words, the controller 30 makes the target output of FC12 lower than the requested output of motor 4 (step S22). By making the remaining capacity adjustment amount a relatively large negative value (by making the target output of FC12 lower than the requested output), the remaining capacity of the battery 11 decreases rapidly from full capacity toward the target capacity.

[0056] In the target output of FC12, in addition to the requested output of motor 4, the power consumption of other electrical devices (such as refrigerator 40) may also be included. However, here, the power consumption of other electrical devices that receive power from FC12 and battery 11 is omitted (the expression "requested output of motor" in steps S12 and S22 is strictly speaking "the total power consumption of all devices (including motor) that receive power from FC and battery").

[0057] If the remaining capacity of battery 11 drops to the target capacity, this flowchart ends (step S23: Yes, return). Then, controller 30 sets the target output of FC12 to the value obtained by adding the remaining capacity adjustment amount to the requested output of motor 4. This remaining capacity adjustment amount is the amount of power that should be supplied to battery 11 to keep its remaining capacity near the target capacity. Furthermore, if the remaining capacity is large, the remaining capacity adjustment amount is set to a negative value. Thus, the requested output cannot be met by the output of FC12 alone, power is supplied from battery 11 to motor 4 (inverter 3), and the remaining capacity decreases. In addition, strictly speaking, the power consumed by other electrical devices that receive power from FC12 and battery 11 is added to the target output of FC12.

[0058] After step S23 is completed, the remaining capacity of the battery 11 is maintained near the target capacity. The regenerated power from the motor 4 is used to charge the battery 11.

[0059] Furthermore, the target capacity other than in step S23 can also deviate slightly from the central value of the suitable range of remaining capacity. In areas where a large amount of renewable electricity is expected, a target capacity lower than the central value of the suitable range is set. In areas where a large amount of renewable electricity cannot be expected, a target capacity higher than the central value of the suitable range is set.

[0060] As described above, the fuel cell vehicle 2 of the first embodiment does not perform reset processing in areas where large amounts of water drainage are not desired (restricted areas). As a result, large amounts of water drainage are avoided in restricted areas.

[0061] (Second Embodiment) In Figure 5 A block diagram of the fuel cell vehicle 2a according to the second embodiment is shown. The fuel cell vehicle 2a of the second embodiment has a combination of two sets of batteries and a fuel cell (FC). Figure 5 The first storage battery 11 and the first FC12 and Figure 1 The first battery 11 and FC 12 are corresponding to the first battery 11 and FC 12. A first auxiliary unit 13 is attached to the first FC 12. In addition to the first battery 11 and FC 12, the fuel cell vehicle 2a also has a second battery 21 and a second FC 22. A second auxiliary unit 23 is attached to the second FC 22. Furthermore, voltage sensor 24 measures the output voltage of the second battery 21, and current sensor 26 measures the current flowing into and out of the second battery 21. Voltage sensor 25 measures the output voltage of the second FC 22, and current sensor 27 measures the output current of the second FC 22. The measurements from voltage sensors 24 and 25, and current sensors 26 and 27 are sent to controller 130. The second battery 21 is a battery of the same type and capacity as the first battery 11, and is a lithium iron phosphate battery.

[0062] The first battery 11 and the first FC12 are connected in parallel. The first battery 11 and the first FC12 are connected to the inverter 3 (motor 4) via the first relay 18. If the first relay 18 is turned on, the connection between the first battery 11 and the first FC12 and the inverter 3 (motor 4) is disconnected.

[0063] The second battery 21 and the second FC22 are connected in parallel. The second battery 21 and the second FC22 are connected to the inverter 3 (motor 4) via the second relay 28. If the second relay 28 is turned on, the connection between the second battery 21 and the second FC22 and the inverter 3 (motor 4) is disconnected.

[0064] Apart from the second battery 21, the second FC 22, voltage sensors 24 and 25, current sensors 26 and 27, and relays 18 and 28, the structure of the fuel cell vehicle 2a in the second embodiment ( Figure 5 The structure of the fuel cell vehicle 2 in the first embodiment ( Figure 1 (Same.) Figure 1 and Figure 5 In the figures, the same reference numerals denote the same parts. For those in... Figure 1 The components described herein are omitted.

[0065] Relays 18 and 28 are controlled by controller 130. If controller 130 closes the first relay 18 and opens the second relay 28, the electrical structure of the fuel cell vehicle 2a in the second embodiment is consistent with the electrical structure of the fuel cell vehicle 2 in the first embodiment. Normally, controller 130 closes the first relay 18 and the second relay 28, driving motor 4 through at least one of the following power sources: first battery 11, second battery 21, first FC12, and second FC22.

[0066] The start conditions for the reset process in the fuel cell vehicle 2a of the second embodiment (such as the fuel cell vehicle 2a being located outside a designated prohibited area or immediately after the main switch of the fuel cell vehicle 2a is turned on) are the same as those in the fuel cell vehicle 2 of the first embodiment.

[0067] As described above, motor 4 generates electricity using the vehicle's inertial energy during braking. The regenerative power generated by motor 4 charges either the first battery 11 or the second battery 21. Conversely, during the reset process, the battery is charged to full capacity. Regenerative power cannot be received from a fully charged battery. The fuel cell vehicle 2a of the second embodiment uses two separate batteries 11 and 21, enabling both reset processing and regenerative power accumulation.

[0068] When the remaining capacity of the second battery 21 falls below a predetermined remaining capacity threshold, the controller 130 of the fuel cell vehicle 2a closes the second relay 28 to connect the second battery 21 and the second fuel cell 22 to the inverter 3 (motor 4). Simultaneously, the controller 130 opens the first relay 18, disconnecting the first battery 11 and the first fuel cell 12 from the inverter 3 (motor 4), and performs a reset process on the first battery 11 using the first fuel cell 12. At this time, since the connection between the first fuel cell 12 and the inverter 3 (motor 4) is disconnected, the controller 130 sets the maximum allowable power of the battery as the target output of the first fuel cell 12. Furthermore, the remaining capacity threshold is set to a value that provides a predetermined safety margin up to the upper limit of a suitable range of battery remaining capacity, even when the anticipated regenerative power is applied to the remaining capacity threshold during the reset process.

[0069] During the reset process of the first battery 11, the first battery 11 and the first FC12 are disconnected from the inverter 3 (motor 4), and also disconnected from the second battery 21 and the second FC22. Therefore, the reset process of the first battery 11 does not affect the operation of the motor 4, the second battery 21, and the second FC22. On the other hand, since the remaining capacity of the second battery 21 is lower than the remaining capacity threshold, regenerated power is stored in the second battery 21. The fuel cell vehicle 2a is able to store regenerated power in the other battery while performing a reset process on one battery.

[0070] After completing the reset process of the first battery 11, the controller 130 closes the first relay 18 to connect the first battery 11 and the first FC12 to the inverter 3 (motor 4), and opens the second relay 28 to disconnect the second battery 21 and the second FC22 from the inverter 3 (motor 4). The controller 130 reduces the output of the first FC12, so that the power from the first battery 11 is used to drive the motor 4. Through this process, the remaining capacity of the first battery 11 decreases.

[0071] If the remaining capacity of the first battery 11 is lower than the remaining capacity threshold, the controller 130 uses the second FC22 to perform a reset process on the second battery 21. Since the connection between the second FC22 and the inverter 3 (motor 4) is disconnected, the controller 130 sets the maximum allowable power of the battery as the target output of the second FC22. During the reset process of the second battery 21, regenerated power is stored in the first battery 11.

[0072] Through the above-described process, the first battery 11 and the second battery 21 are alternately reset. During the charging of one battery through the reset process, regenerated power is stored in the other battery.

[0073] The remaining capacity threshold can also be adjusted based on the area where the fuel cell vehicle 2a operates. For example, in areas where braking is frequently used on the street, a larger amount of regenerative power can be expected. In such cases, the remaining capacity threshold is set lower, allowing for a greater accumulation of regenerative power in the battery. Conversely, in areas with fewer traffic lights, a larger amount of regenerative power cannot be expected, so the remaining capacity threshold can be set higher.

[0074] (Modified example) In Figure 6 A block diagram of a modified fuel cell vehicle 2b according to the second embodiment is shown. The fuel cell vehicle 2b has first relays 18a and 18b instead of the first relay 18 of the fuel cell vehicle 2a of the second embodiment, and second relays 28a and 28b instead of the second relay 28. Except for the configuration of the first relays 18a and 18b and the second relays 28a and 28b, the structure of the fuel cell vehicle 2b is the same as that of the fuel cell vehicle 2a of the second embodiment.

[0075] Opening the first relay 18a disconnects the connection between the first FC12 and the inverter 3 (motor 4). Closing the first relay 18a connects the first FC12 to the inverter 3 (motor 4). Opening the first relay 18b disconnects the connection between the first battery 11 and the inverter 3 (motor 4). Closing the first relay 18b connects the first battery 11 to the inverter 3 (motor 4).

[0076] Opening the second relay 28a disconnects the connection between the second FC22 and the inverter 3 (motor 4). Closing the second relay 28a connects the second FC22 to the inverter 3 (motor 4). Opening the second relay 28b disconnects the connection between the second battery 21 and the inverter 3 (motor 4). Closing the second relay 28b connects the second battery 21 to the inverter 3 (motor 4).

[0077] The first relays 18a and 18b, and the second relays 28a and 28b are controlled by the controller 130. When both first relays 18a and 18b are simultaneously turned on and off, they function the same as the first relay 18 in the second embodiment. When both second relays 28a and 28b are simultaneously turned on and off, they function the same as the second relay 28 in the second embodiment. The controller 130 may also, depending on the situation, turn on one of the two first relays 18a and 18b and close the other. The controller 130 may also, depending on the situation, turn on one of the two second relays 28a and 28b and close the other.

[0078] For example, when an anomaly is detected in the first FC12, the controller 130 opens the first relay 18a while keeping the first relay 18b closed, disconnecting the first FC12 from the system. Alternatively, when an anomaly is detected in the first battery 11, the controller 130 opens the first relay 18b while keeping the first relay 18a closed, disconnecting the first battery 11 from the system. The same applies when an anomaly is detected in the second FC22, or when an anomaly is detected in the second battery 21.

[0079] Notes relating to the techniques described in the embodiments are presented. The fuel cell vehicles 2 and 2a of the embodiments may be equipped with any rechargeable battery, and there are no restrictions on their type. However, the techniques disclosed in this specification are suitable for fuel cell vehicles equipped with batteries having a stable region (a region where the change in battery output voltage is minimal relative to changes in remaining capacity). This is because the current accumulation method is more suitable for inferring the remaining capacity of a battery with a stable region, and the techniques disclosed in this specification relate to reset processing to eliminate errors in the current accumulation method.

[0080] The relationship between full voltage (equivalent to the output voltage of a fully charged battery) and full capacity (the remaining capacity of the battery when it outputs full voltage) can also be influenced by battery temperature and internal resistance as parameters. By further incorporating battery temperature and internal resistance to determine the relationship between full voltage and full capacity, the initial value of the remaining battery capacity (full capacity at full voltage) during reset can be determined more accurately.

[0081] The fuel cell vehicle 2 of the first embodiment may also have a switch 36 for preventing reset processing (see reference). Figure 1 Switch 36 is connected to controller 30. If the user turns switch 36 to OFF, controller 30 will not perform a reset procedure under any circumstances. If the user turns switch 36 to ON, it can... Figures 2-4 The reset process is performed using a flowchart. By providing switch 36, the reset process can be disabled by user judgment. The fuel cell vehicles 2a and 2b of the second embodiment may also be equipped with a switch to disable the reset process.

[0082] Alternatively, fuel cell vehicles 2, 2a, and 2b can also prevent reset from occurring from the moment the main switch of the fuel cell vehicle is turned on until a predetermined distance has been traveled. The predetermined distance can be arbitrarily set by the user via a navigation system or other means.

[0083] The fuel cell vehicle 2a of the second embodiment has two batteries and two FCs. The technology disclosed in this specification can also have three or more batteries and three or more FCs. In this case, any two batteries and any two FCs need to satisfy the relationship of the second embodiment (alternating reset of the two batteries).

[0084] The specific examples of the present invention have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes technologies modified or altered from the specific examples described above. The technical elements described in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful.

Claims

1. A fuel cell vehicle, characterized in that, The fuel cell vehicle has the following features: Fuel cells; A rechargeable battery; The controller that controls the fuel cell; and A driving motor that receives power from at least one of the fuel cell and the battery. The controller performs a reset process outside areas where excessive drainage is not desired, charging the battery to a full voltage equivalent to a full charge using the output power of the fuel cell. If at least one of the following conditions 1 to 3 is met, the controller begins the reset process: Condition 1: After the main switch of the fuel cell vehicle is turned on; Condition 2: After the main switch is turned on again after a specified placement time has elapsed during the period when the main switch is off; Condition 3: The time taken to process the remaining capacity estimation of the battery based on the cumulative current value calculated relative to the current flowing into and out of the battery exceeds a predetermined duration. During the period from the start of the reset process to the start of the reset process, the controller sets the target output of the fuel cell to the requested output of the motor. Outside of the period from the generation of the trigger until the end of the reset process, the controller sets the target output of the fuel cell to the value obtained by adding the remaining capacity adjustment of the battery to the requested output of the motor. In the reset process, the controller sets the target output of the fuel cell to the value obtained by adding the maximum allowed battery power to the requested output of the motor. The maximum allowed battery power is the maximum value of power permitted to be supplied to the battery. In the reset process, when the motor's requested output increases sharply, the controller supplies a predetermined portion of the power intended for charging the battery to the motor; when the battery output is less than the requested output, power is output from the battery. If regenerated power is generated during the reset process, the controller sets the target output of the fuel cell to the value obtained by subtracting the regenerated power from the maximum allowable power of the battery. During the reset process, the controller may interrupt the reset process if the vehicle enters an area where excessive drainage is undesirable, if the vehicle speed falls below a certain threshold, or if the vehicle noise level falls below a certain threshold. During the interruption of the reset process, the controller sets the target output of the fuel cell to the requested output of the motor.

2. The fuel cell vehicle according to claim 1, characterized in that, The battery includes a first battery and a second battery capable of storing the regenerative power of the motor. The fuel cell includes a first fuel cell and a second fuel cell. When the remaining capacity of the second battery is lower than a specified remaining capacity threshold, the controller connects the second battery and the second fuel cell to the motor, disconnects the first battery and the first fuel cell from the motor, and uses the first fuel cell to perform the reset process on the first battery.

3. The fuel cell vehicle according to claim 2, characterized in that, After completing the reset process of the first battery, the controller connects the first battery and the first fuel cell to the motor, and disconnects the second battery and the second fuel cell from the motor. If the remaining capacity of the first battery is lower than the specified remaining capacity threshold, the controller uses the second fuel cell to perform the reset process on the second battery.

4. The fuel cell vehicle according to claim 2 or 3, characterized in that, have: First relay; and Second relay, The first storage battery and the first fuel cell are connected to the motor via the first relay. The second battery and the second fuel cell are connected to the motor via the second relay. The controller controls the opening and closing of the first relay and the second relay.

5. The fuel cell vehicle according to claim 1, characterized in that, It has a switch to disable the reset process. The switch is connected to the controller. When the switch is turned off, the controller does not perform the reset process.

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