Fuel cell vehicle and method of operating the same

Abstract

The application relates to the technical field of fuel cell vehicles, and provides a fuel cell vehicle and an operation method thereof. The fuel cell vehicle comprises a fuel cell system and a low-voltage auxiliary battery system, and the operation method comprises the following steps: when the fuel cell vehicle is cold started, the low-voltage auxiliary battery system is controlled to supply power to the fuel cell system, so that the stack is warmed up; during the operation process after the fuel cell vehicle is started, the power output strategy of the fuel cell system is determined; the operation power interval of the fuel cell system is determined; the output power of the fuel cell system is controlled to be maintained in the operation power interval, and the fuel cell system and the low-voltage auxiliary battery system are controlled to jointly provide the required power of the fuel cell vehicle. The fuel cell vehicle provided by the application replaces the high-voltage battery pack with the low-voltage auxiliary battery system, and the required power of the fuel cell vehicle is provided by the low-voltage auxiliary battery system in cooperation with the fuel cell system, so that the weight of the vehicle is reduced and the manufacturing cost is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell vehicles, in particular to a fuel cell vehicle and a method for operating the same. BACKGROUND

[0002] A fuel cell vehicle is a vehicle that works by using hydrogen and oxygen as fuel to generate electric energy. In the related art, a high-voltage battery pack (such as a battery pack with a voltage higher than 400V) is usually arranged in a fuel cell vehicle to provide backup power for the fuel cell vehicle. However, the high-voltage battery pack has a large weight, a large amount of electric quantity, a large number of electric cells, and a complex control, and due to the high voltage, a corresponding safety protection mechanism also needs to be arranged, which results in a large weight and high cost of the vehicle. SUMMARY

[0003] Therefore, the present application aims to provide a fuel cell vehicle and a method for operating the same to reduce the cost and the weight of the vehicle.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for operating a fuel cell vehicle, and the method is implemented as follows:

[0005] The method for operating a fuel cell vehicle, the fuel cell vehicle comprising a fuel cell system and a low-voltage auxiliary battery system, and the method comprising:

[0006] controlling the low-voltage auxiliary battery system to supply power to the fuel cell system to warm up the electric pile in the fuel cell system when the fuel cell vehicle is cold started, and until the fuel cell vehicle is cold started;

[0007] determining a power output strategy of the fuel cell system according to an operating mode of the fuel cell vehicle in a running process after the fuel cell vehicle is started, wherein the power output strategy represents a distribution rule of the output power of the fuel cell system;

[0008] determining an operating power range of the fuel cell system according to an electric quantity of the low-voltage auxiliary battery system, the operating mode of the fuel cell vehicle, and a demand power of the fuel cell vehicle;

[0009] controlling the output power of the fuel cell system to maintain in the operating power range, and controlling the fuel cell system and the low-voltage auxiliary battery system to jointly provide the demand power for the fuel cell vehicle according to the determined power output strategy.

[0010] Further, the fuel cell vehicle further comprises an air compressor and a hydrogen storage system, the fuel cell system comprises a cooling circuit connected to the electric pile, and the cooling circuit is provided with an electric heating element.

[0011] wherein, when the fuel cell vehicle is cold started, the control of the low-voltage auxiliary battery system to supply power to the fuel cell system to warm up the stack of the fuel cell system comprises:

[0012] controlling the low-voltage auxiliary battery system to supply power to a coolant pump in the cooling loop to start the cooling loop, and controlling the low-voltage auxiliary battery system to output a pulse current to the electric heating element to heat the coolant in the cooling loop;

[0013] controlling the low-voltage auxiliary battery system to supply power to an air compressor in the fuel cell system when the temperature of the stack reaches a first preset temperature threshold;

[0014] controlling the low-voltage auxiliary battery system to stop supplying power to the fuel cell system when the temperature of the stack reaches a second preset temperature threshold.

[0015] Further, the control of the low-voltage auxiliary battery system to output a pulse current to the electric heating element to heat the coolant in the cooling loop comprises:

[0016] obtaining an inlet temperature of the coolant entering the stack and an outlet temperature of the coolant flowing out of the stack, and calculating a temperature difference of the coolant after passing through the stack;

[0017] determining an amplitude and a duty cycle of the pulse current output to the electric heating element according to the temperature difference and the inlet temperature in a preset determination manner;

[0018] controlling the low-voltage auxiliary battery system to output a pulse current to the electric heating element according to the determined amplitude and duty cycle;

[0019] The preset determination manner comprises:

[0020] when a ratio of the temperature difference to the inlet temperature is greater than a first preset ratio, determining the amplitude of the pulse current to be a first preset amplitude and the duty cycle to be a first preset duty cycle;

[0021] when the ratio is not greater than the first preset ratio and is greater than a second preset ratio, determining the amplitude of the pulse current to be a second preset amplitude and the duty cycle to be a second preset duty cycle;

[0022] when the ratio is not greater than the second preset ratio, determining the amplitude and the duty cycle of the pulse current according to the outlet temperature and the second preset temperature threshold;

[0023] The power outputted by the pulse current corresponding to the first preset amplitude and the first preset duty ratio in a unit time is greater than the power outputted by the pulse current corresponding to the second preset amplitude and the second preset duty ratio in a unit time.

[0024] Further, the operation power range of the fuel cell system is determined according to the electric quantity of the low-voltage auxiliary battery system, the operation mode of the fuel cell vehicle, and the demand power of the fuel cell vehicle, and the method comprises the following steps:

[0025] In the case that the operation mode is the preset normal operation mode, the operation power range of the fuel cell system is determined according to the electric quantity of the low-voltage auxiliary battery system.

[0026] In the case that the operation mode is the preset economic operation mode and the electric quantity of the low-voltage auxiliary battery system is lower than a first preset electric quantity threshold, the operation power range is determined as a preset high-efficiency power range.

[0027] In the case that the operation mode is the preset motion mode, the operation power range of the fuel cell system is determined according to the demand power of the fuel cell vehicle.

[0028] Further, in the case that the operation mode is the preset normal operation mode, the control of the fuel cell system and the low-voltage auxiliary battery system to jointly provide the demand power for the fuel cell vehicle comprises the following steps:

[0029] In the case that the electric quantity of the low-voltage auxiliary battery system is not lower than a second preset electric quantity threshold, the output power of the low-voltage auxiliary battery system is controlled as the demand power, and the fuel cell system is controlled to be shut down.

[0030] In the case that the electric quantity of the low-voltage auxiliary battery system is lower than the second preset electric quantity threshold, the fuel cell system is controlled to provide the demand power for the fuel cell vehicle while charging the low-voltage auxiliary battery system.

[0031] Further, in the case that the operation mode is the preset economic operation mode, the control of the fuel cell system and the low-voltage auxiliary battery system to jointly provide the demand power for the fuel cell vehicle comprises the following steps:

[0032] In the case that the electric quantity of the low-voltage auxiliary battery system is not lower than the first preset electric quantity threshold, the output power of the low-voltage auxiliary battery system is controlled as the demand power.

[0033] Further, in the case that the operation mode is the preset motion mode, the control of the fuel cell system and the low-voltage auxiliary battery system jointly providing the demand power for the fuel cell vehicle comprises:

[0034] controlling the fuel cell system to provide the demand power for the fuel cell vehicle only;

[0035] controlling the low-voltage auxiliary battery system to provide the demand power for the fuel cell vehicle together in the case that the fuel cell system cannot meet the demand power of the fuel cell vehicle.

[0036] Further, the operation method further comprises:

[0037] obtaining road condition information of the fuel cell vehicle;

[0038] controlling the low-voltage auxiliary battery system to provide demand power for the fuel cell vehicle and controlling the fuel cell system to charge the low-voltage auxiliary battery system according to the residual power of the low-voltage auxiliary battery system in the case that the obtained road condition information is preset congestion road condition.

[0039] Further, the operation method further comprises:

[0040] obtaining fault information of the stack;

[0041] controlling the low-voltage auxiliary battery system to supply power for the fuel cell vehicle according to a preset power supply strategy in the case that the stack has a preset fault.

[0042] Compared with the related art, the present application has at least the following advantages:

[0043] (1) The operation method of the fuel cell vehicle disclosed by the present application replaces the traditional high-voltage battery system provided with a high-voltage battery pack with a low-voltage auxiliary battery system. In this way, a high-voltage battery pack does not need to be configured, and only a low-voltage storage battery, i.e., a low-voltage auxiliary battery system, needs to be configured. The weight of the low-voltage storage battery is lower than that of the high-voltage battery pack, so the weight of the fuel cell vehicle can be reduced. At the same time, the low-voltage auxiliary battery system has a small amount of power and a low voltage compared with the high-voltage battery system, and the control is relatively simple, and the requirement for the safety protection mechanism is lower, so the manufacturing cost can be reduced. That is, the present application can reduce the manufacturing cost and the weight of the whole vehicle by replacing the traditional high-voltage battery system with a low-voltage auxiliary battery system.

[0044] At the same time, the operation method of the fuel cell vehicle disclosed by the present application utilizes the low-voltage auxiliary battery system to output a pulse current to warm up the stack of the fuel cell at cold start, which is conducive to reducing the cold start duration of the fuel cell vehicle and improving the cold start efficiency of the fuel cell vehicle.

[0045] And, during the operation of the fuel cell vehicle, through the power output strategy and the setting of the operation power range, the fuel cell system and the low-voltage auxiliary battery system work together, the energy distribution of the fuel cell system and the low-voltage auxiliary battery system is optimized, and the driving demand of the user is met.

[0046] (2) When cold starting, the low-voltage auxiliary battery system supplies power to the cooling liquid pump, the electric heating element, the air compressor and other equipment, and the electric heating element is used to cooperate with the pulse current to heat the electric pile, which is beneficial to improve the cold start efficiency of the fuel cell system.

[0047] (3) The pulse current of the low-voltage auxiliary battery system is adjusted to adjust the heating capacity of the cooling liquid, which is beneficial to adaptively reduce the power consumption of the low-voltage auxiliary battery system in the cold start process.

[0048] (4) According to different operation modes (normal, economic, sports) and the power of the low-voltage auxiliary battery system, the demand power of the vehicle, the operation power range of the fuel cell system is determined, which is beneficial to improve the adaptability and performance of the vehicle in different scenes.

[0049] (5) By adopting different power supply strategies according to the power of the low-voltage auxiliary battery system in the preset normal operation mode, when the power is sufficient, the low-voltage auxiliary battery system supplies power alone and the fuel cell system is shut down, when the power is insufficient, the fuel cell system supplies power to the vehicle and charges the low-voltage auxiliary battery system. This is beneficial to save hydrogen consumption and enable the vehicle to run continuously and supplement the power in time, which is beneficial to improve the energy utilization efficiency of the vehicle in the normal operation mode.

[0050] (6) By controlling the low-voltage auxiliary battery system to provide the demand power of the vehicle in the preset economic operation mode, in the case of low power, the fuel cell system operates in the preset high-efficiency power range to charge the low-voltage auxiliary battery system, which is beneficial to reduce the waste of hydrogen caused by the operation of the fuel cell system in other low-efficiency power ranges, thereby improving the economy of the fuel cell system.

[0051] (7) By prioritizing the fuel cell system to provide demand power in the preset sports mode, when the fuel cell system cannot meet the demand, the low-voltage auxiliary battery system cooperates to supply power. This can improve the acceleration ability and power response speed of the vehicle, and is beneficial to meet the user's demand for high-performance driving.

[0052] (8) By acquiring road condition information, the low-voltage auxiliary battery system is controlled to provide required power for the vehicle under a preset congested road condition, and the output power of the fuel cell system is controlled according to the remaining power. This helps to reduce the start-stop frequency of the fuel cell system in congestion, reduces the start-up loss of the fuel cell system, and helps to prolong the service life of the fuel cell system.

[0053] (9) By controlling the low-voltage auxiliary battery system to supply power to the vehicle according to a preset power supply strategy when a preset fault occurs in the stack, the vehicle can continue to operate when the fuel cell system fails. In this way, the low-voltage auxiliary battery system provides emergency protection for users, which helps to reduce the adverse effects of fuel cell system failure.

[0054] The second aspect of the present application also proposes a fuel cell vehicle, which comprises a fuel cell system, a low-voltage auxiliary battery system, and a controller.

[0055] The controller is connected to the fuel cell system and the low-voltage auxiliary battery system, and the controller comprises a processor, a memory, and a computer program stored in the memory. When the computer program is executed by the processor, the controller executes the operation method of the fuel cell vehicle described above.

[0056] The fuel cell vehicle described in the present application uses a low-voltage auxiliary battery system to replace the conventional high-voltage battery system with a high-voltage battery pack, which helps to reduce the weight of the vehicle and reduce its manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0057] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The accompanying drawings do not constitute an inappropriate limitation on the present application. In the drawings:

[0058] Figure 1 The connection diagram of the modules of the fuel cell vehicle described in the embodiments of the present application;

[0059] Figure 2 The flowchart of the operation method of the fuel cell vehicle described in the embodiments of the present application;

[0060] Figure 3 The flowchart of the cold start process in the operation method of the fuel cell vehicle described in the embodiments of the present application;

[0061] Figure 4 The flowchart of the phased adjustment in the cold start process in the operation method of the fuel cell vehicle described in the embodiments of the present application;

[0062] Figure 5A flowchart of determining the operation power range of the fuel cell system in the operation method of the fuel cell vehicle according to the embodiment of the present application is shown in FIG. 1.

[0063] Figure 6 A flowchart of the power output control in the normal operation mode in the operation method of the fuel cell vehicle according to the embodiment of the present application is shown in FIG. 2.

[0064] Explanation of reference numerals:

[0065] 1. A fuel cell system;

[0066] 2. A low-voltage auxiliary battery system; 21, 48V low-voltage battery system; 22, bidirectional DC / DC converter;

[0067] 3. A controller. DETAILED DESCRIPTION

[0068] In order to make the technical solutions of the present application and the advantages thereof clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0069] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0070] In addition, in the description of the present application, it should be noted that if terms indicating orientation or position relationship such as "upper", "lower", "inner", "outer" and the like appear, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, if the terms "first", "second" and the like appear, they are also only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0071] In addition, in the description of the present application, unless otherwise explicitly limited, the terms "mounting", "connection", "connecting", "connector" should be understood broadly. For example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood in combination with the specific circumstances.

[0072] In this application, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described particular features, structures, materials, or characteristics can be combined in any appropriate manner in one or more embodiments or examples.

[0073] In the following, the present application will be specifically described through exemplary embodiments. However, it should be understood that the elements, structures and features in one embodiment can also be beneficially combined into other embodiments without further description.

[0074] Embodiments of the first aspect of the present application provide a method for operating a fuel cell vehicle, which replaces the conventional high-voltage battery system provided with a high-voltage battery pack with a low-voltage auxiliary battery system 2, and uses the low-voltage auxiliary battery system 2 to assist the cold start of the fuel cell system 1 and to assist the operation of the vehicle. In this way, since only the low-voltage auxiliary battery system 2 needs to be configured without the need to configure the high-voltage battery pack, the scheme of the present application for replacing the conventional high-voltage battery system with the low-voltage auxiliary battery system 2 can reduce the manufacturing cost and the overall vehicle weight, while also being conducive to improving the cold start efficiency of the vehicle and facilitating the driving needs of the user.

[0075] In the related art, a fuel cell vehicle includes a fuel cell system 1, which converts hydrogen energy to drive the vehicle to travel. In addition, in order to meet the actual operation needs of the fuel cell vehicle, a high-voltage battery system is usually also provided in the related art, which includes a high-voltage battery pack (such as a lithium battery with a voltage level of 400V and above), a heat dissipation component, and a corresponding BMS (Battery Management System), etc., to use the high-voltage battery system as a backup power source.

[0076] Specifically, the high-voltage battery system in the related art is used to assist the start of the fuel cell on the one hand, for example, the start of the fuel cell needs to control the opening of the air compressor, the hydrogen circulating pump and other equipment, and power is supplied through the high-voltage battery system. On the other hand, the high-voltage battery system is also used to provide high-power support for the fuel cell vehicle. For example, when the fuel cell system 1 (limited by the electrochemical reaction rate) cannot quickly respond to the instantaneous high-power demand of the vehicle, the high-power provided by the high-voltage battery pack can make up for the power gap. In addition, during the vehicle braking or deceleration process, the high-voltage battery pack can also be used to realize energy recovery.

[0077] However, there are certain disadvantages in applying the high-voltage battery system in the fuel cell vehicle, specifically in that:

[0078] From the weight dimension, the high-voltage battery pack arranged in the high-voltage battery system itself is composed of a large number of cell cooling components and the like, and the weight of a single pack can usually reach several hundred kilograms. If the vehicle body weight is heavy, in order to drive a heavier vehicle body, the fuel cell needs to continuously output higher power, which indirectly increases the consumption of hydrogen.

[0079] From the cost dimension, the high-voltage battery system has large electric quantity, many cells, and complex control. At the same time, due to high voltage, the high-voltage battery system has extremely strict requirements for safety protection, such as the need to be equipped with a high-voltage distribution box, an insulation monitoring device, a collision power-off protection mechanism, and a series of safety components. These components further increase the manufacturing cost and assembly complexity of the whole vehicle.

[0080] In view of this, in order to overcome the deficiencies in the related art, the operation method of the fuel cell vehicle in the embodiment is applied to the fuel cell vehicle. Specifically, the fuel cell vehicle includes a fuel cell system 1 and a low-voltage auxiliary battery system 2.

[0081] More specifically, Figure 1 A module connection diagram of the fuel cell vehicle is shown, referring to Figure 1 The fuel cell vehicle can specifically include a fuel cell system 1, a low-voltage auxiliary battery system 2, a controller 3, an on-board hydrogen storage system composed of a plurality of hydrogen storage bottles, and can also include key devices of the vehicle transmission system such as a motor, a transmission, a reducer, and a differential, as well as high-voltage accessories.

[0082] The motor is used to output torque to convert electrical energy into mechanical energy and provide power. The reducer amplifies the torque and reduces the speed by fixing the transmission ratio; the transmission adapts the speed-torque demand of different working conditions by variable transmission ratio; and the differential ensures the differential rotation of the wheels and ensures the stable transmission of power to the wheels. The transmission, reducer, and differential work together to realize the distribution of vehicle power and the adjustment of speed and torque. In specific implementation, the motor can establish a transmission path between the motor and the wheels via the reducer and the differential, or the motor can also establish a transmission path between the motor and the wheels via the transmission and the differential to drive the vehicle to travel.

[0083] The controller 3 specifically includes a motor controller, a vehicle controller, a battery controller (battery management system), and a fuel controller. The motor controller of the vehicle sends the power required for driving to the vehicle controller, and then the vehicle controller sends the power required for driving to the BMS (Battery Management System, battery management system) system and the fuel controller FCU (Fuel and Control Unit, fuel controller) respectively, so that the BMS system and the fuel controller FCU control the battery and the fuel cell system to provide the required power, respectively.

[0084] The low-voltage auxiliary battery system 2 can specifically include a 48V low-voltage battery system 21 formed by two 24V storage batteries connected in series, and a bidirectional DC / DC converter 22, wherein the 48V low-voltage battery system 21 is connected in series with the bidirectional DC / DC converter 22. In addition, in order to be able to charge the 48V low-voltage battery system 21, the low-voltage auxiliary battery system 2 can further include a charging port to connect an external charging device through which the low-voltage auxiliary battery system 2 is charged by the external charging device. More specifically, the charging current delivered by the external charging device passes through the bidirectional DC / DC converter 22 and is converted into low-voltage direct current to charge the 48V low-voltage battery system 21.

[0085] As can be seen, the present embodiment replaces the conventional high-voltage battery system with the low-voltage auxiliary battery system 2, without configuring a high-voltage battery pack, but configuring the low-voltage auxiliary battery system 2, i.e. two 24V storage batteries and the bidirectional DC / DC converter 22. This replaces the high-voltage battery system with a relatively low weight with the low-voltage auxiliary battery system 2, which is beneficial to reduce the weight of the fuel cell vehicle.

[0086] At the same time, since the low-voltage auxiliary battery system 2 has a small amount of electricity and a low voltage, the control is relatively simple, and in the case of a vehicle danger (such as a collision, etc.), compared with the high-voltage battery system, the low-voltage auxiliary battery system 2 poses less threat to the safety of the vehicle owner. Therefore, the low-voltage auxiliary battery system 2 has lower requirements for safety protection mechanisms, thereby reducing manufacturing costs. As can be seen, the present embodiment replaces the conventional high-voltage battery system with the low-voltage auxiliary battery system 2, which can reduce manufacturing costs and reduce the weight of the whole vehicle, and improve safety.

[0087] The fuel cell system 1 generates electricity using hydrogen stored by the on-board hydrogen storage system. The electrical energy output by the 48V low-voltage battery system 21 is used after being boosted by the bidirectional DC / DC converter 22. The controller 3 distributes the electrical energy of the fuel cell system 1 and the electrical energy output by the low-voltage auxiliary battery system 2 to drive the fuel cell vehicle to travel.

[0088] The operation method of the fuel cell vehicle described in the present embodiment is executed by the controller 3, specifically, Figure 2 The flow of the operation method of the fuel cell vehicle is shown, and in combination with Figure 2 , the overall design, the operation method of the fuel cell vehicle includes the following steps S210-S240.

[0089] Step S210, when the fuel cell vehicle is cold started, the low-voltage auxiliary battery system 2 supplies power to the fuel cell system 1 to warm up the stack in the fuel cell system 1, and until the fuel cell vehicle is cold started.

[0090] Specifically, the cold start refers to a process of starting the fuel cell vehicle when the temperature of the stack is low (usually lower than the ambient temperature or much lower than the normal working temperature, such as lower than 0℃). For example, the start of the vehicle after overnight parking in a -15℃ environment in winter.

[0091] The stack in the fuel cell system 1 is the core component of the fuel cell, which is internally composed of a plurality of single cells connected in series, and generates electric energy through the electrochemical reaction of hydrogen and oxygen. Each single cell includes a proton exchange membrane, an anode plate and a cathode plate.

[0092] For the fuel cell, the core principle of the fuel cell is that the oxidation-reduction reaction of hydrogen and oxygen occurs on the electrode surface of the stack to generate electric energy, which depends on the proton conduction ability of the proton exchange membrane and the activity of the electrode catalyst. On the one hand, in a low temperature environment, the fuel cell cannot be directly started, because if the fuel cell is directly started at a low temperature of the stack, the product water generated by the reaction will freeze on the electrode surface, increasing the risk of local failure of the stack.

[0093] On the other hand, in a low temperature environment (such as lower than 0℃), the water in the proton exchange membrane will freeze or the viscosity will increase, and the protons will also be difficult to pass through the membrane layer smoothly, and in a low temperature environment, the catalyst activity on the electrode surface will be greatly attenuated, and it is difficult to efficiently catalyze the reaction of hydrogen and oxygen, and it is difficult to efficiently generate electricity. When the temperature of the fuel cell stack reaches the normal working temperature (for example, 60℃-80℃), the fuel cell stack can normally and efficiently generate electricity.

[0094] Therefore, in the cold start process, it is generally necessary to first assist the stack of the fuel cell to warm up, and only when the stack of the fuel cell is warmed up to a certain temperature, the fuel cell stack can be started to generate electricity.

[0095] In step S210 of the embodiment, in order to assist the cold start of the fuel cell vehicle, the low-voltage auxiliary battery system 2 can supply power to the fuel cell system 1 to warm up the stack of the fuel cell system 1 when the fuel cell vehicle is cold started. Specifically, the low-voltage auxiliary battery system 2 can output a pulse current to the electric heating element arranged in the fuel cell system 1, and use the Joule heat generated by the electric heating element and the pulse current to heat the stack, thereby warming up the stack in the fuel cell system 1.

[0096] In this way, the cold start of the fuel cell vehicle can be assisted to warm up, the cold start time of the fuel cell vehicle can be reduced, and the cold start efficiency of the fuel cell vehicle can be improved, and at the same time, the adverse effects of direct reaction of the stack in a low temperature state on the stack can be prevented.

[0097] It is worth mentioning that in the cold start process, when the temperature of the stack is raised to a certain temperature, for example, above 25℃, the reaction required gas can be started to be supplied to the stack, specifically, the low-voltage auxiliary battery system 2 can start to supply power to the air compressor and other gas inlet equipment to start the gas supply, start the stack to generate electricity, and when the stack temperature reaches the normal working temperature, for example, 65℃, the low-voltage auxiliary battery system 2 stops power supply and also stops outputting pulse current, and the cold start is ended. Or it can also be that when the stack temperature is raised to 25℃, the gas is not supplied, that is, the stack is not started, and the low-voltage auxiliary battery system 2 continues to output pulse current to heat the stack by external heating. When the stack temperature reaches the normal working temperature, for example, 65℃, the low-voltage auxiliary battery system 2 starts to supply power to the air compressor and other gas inlet equipment to start the gas supply, so that the stack starts normal power generation, and then the low-voltage auxiliary battery system 2 stops power supply, and the cold start is ended.

[0098] The low-voltage auxiliary battery system 2 outputs pulse current to heat the stack of the fuel cell during the cold start of the stack through step S210, which is beneficial to reduce the cold start time of the fuel cell vehicle and improve the cold start efficiency of the fuel cell vehicle.

[0099] In step S220, during the running process after the start of the fuel cell vehicle, the power output strategy of the fuel cell system 1 is determined according to the running mode of the fuel cell vehicle.

[0100] The power output strategy represents the distribution rule of the output power of the fuel cell system 1.

[0101] In step S230, the running power interval of the fuel cell system 1 is determined according to the electric quantity of the low-voltage auxiliary battery system 2, the running mode of the fuel cell vehicle, and the demand power of the fuel cell vehicle.

[0102] In step S240, the output power of the fuel cell system 1 is controlled to maintain in the running power interval, and the fuel cell system 1 and the low-voltage auxiliary battery system 2 are controlled to jointly provide the demand power of the fuel cell vehicle according to the determined power output strategy.

[0103] Specifically, in steps S220-S240, during the running process after the start of the fuel cell vehicle, the starting, driving, acceleration and the like of the fuel cell vehicle need power support, and the required power is determined according to the motion state in front of the vehicle controlled by the user. In this embodiment, the demand power is provided by the low-voltage auxiliary battery system 2 and the fuel cell system 1.

[0104] More specifically, the embodiment determines the power output strategy of the fuel cell system 1 and determines the operation power range of the fuel cell system 1 according to the operation mode of the fuel cell vehicle, and controls the output power of the fuel cell system 1 to maintain in the operation power range and distribute the output power according to the power output strategy during operation, while the low-voltage auxiliary battery system 2 is used to jointly provide the required power for the fuel cell vehicle.

[0105] In this way, by setting the power output strategy and the operation power range, the fuel cell system 1 and the low-voltage auxiliary battery system 2 are facilitated to work cooperatively, and the energy distribution of the fuel cell system 1 and the low-voltage auxiliary battery system 2 is optimized, so as to facilitate to meet the driving requirements of the user.

[0106] Continuing from Figure 2 , and in combination with Figure 3 In some exemplary embodiments, in step S210, when the fuel cell vehicle is cold started, the low-voltage auxiliary battery system 2 is controlled to supply power to the fuel cell system 1 to warm up the stack of the fuel cell system 1, which can be achieved by the following steps S211-S213.

[0107] In step S211, the low-voltage auxiliary battery system 2 is controlled to supply power to the cooling liquid pump in the cooling circuit to start the cooling circuit, and the low-voltage auxiliary battery system 2 is controlled to output pulse current to the electric heating element to heat the cooling liquid in the cooling circuit.

[0108] Specifically, the fuel cell system 1 includes a cooling circuit connected to the stack, and the cooling circuit is provided with an electric heating element. The cooling circuit is a pipeline system connected to the stack of the fuel cell and used to circulate cooling liquid, and the heat exchange between the cooling liquid and the stack can be achieved through the cooling liquid to adjust the temperature of the stack and maintain the stability of the stack temperature. Specifically, the cooling circuit is provided with a cooling liquid pump for circulating the cooling liquid in the pipeline.

[0109] In step S212, when the temperature of the stack reaches a first preset temperature threshold, the low-voltage auxiliary battery system 2 is controlled to supply power to the air compressor in the fuel cell system 1.

[0110] The air compressor is a device for providing pure air to the stack of the fuel cell system 1 to provide oxygen required for the reaction of the stack. When it is detected that the temperature of the stack reaches the first preset temperature threshold, the air compressor is started to supply the required gas for the reaction of the stack, that is, the low-voltage auxiliary battery system 2 is started to supply power to the air compressor. In addition, the hydrogen circulation pump and the hydrogen supply valve of the fuel cell vehicle can also be started to supply power by the low-voltage auxiliary battery system 2, and the hydrogen supply to the stack is also started.

[0111] In one embodiment, the first preset temperature threshold can be set as the temperature at which the stack can react efficiently, and can be set as the temperature at which the cold start ends, i.e. the temperature at which the fuel cell stack can generate electricity efficiently, for example 65℃. When the temperature of the fuel cell stack reaches 65℃, the proton conduction capability of the proton exchange membrane of the stack and the activity of the electrode catalyst are at a high level, and the stack temperature is high, and the water produced by the electrochemical reaction will not freeze on the surface of the stack, and the stack is in the efficient reaction zone.

[0112] In another embodiment, the first preset temperature threshold can also be determined according to the initial stack temperature at the beginning of the cold start and the initial electric quantity of the low-voltage auxiliary battery system 2, and according to the hydrogen consumption rate of the stack at different stack temperatures.

[0113] For example, when the stack temperature is low at the beginning of the cold start, or the initial electric quantity of the low-voltage auxiliary battery system 2 is low, or both the stack temperature and the initial electric quantity of the low-voltage auxiliary battery system 2 are low, the stack can be supplied with reaction gas when the stack temperature is 25℃ (this value can be calculated according to the actual situation, and 25℃ is an example). Instead of waiting until the stack temperature reaches 65℃ (the preset temperature threshold at which the stack can react efficiently, or the cold start end temperature threshold) to start the air supply, if the air supply is still waited until the stack temperature reaches 65℃, the electric quantity of the low-voltage auxiliary battery system 2 will be too low to continue heating the stack, which will affect the duration of the cold start of the stack.

[0114] Step S213, when the temperature of the stack reaches the second preset temperature threshold, the low-voltage auxiliary battery system 2 is controlled to stop supplying power to the fuel cell system 1.

[0115] The second preset temperature threshold can be set as the temperature at which the stack can react efficiently, i.e. can be set as the preset cold start end temperature. When the temperature of the stack reaches the second preset temperature threshold, it indicates that the temperature of the stack has risen to the temperature at which it can react efficiently, and the cold start ends. For example, the second preset temperature threshold can be 65℃.

[0116] Specifically, the cold start process of the fuel cell vehicle is described below with an example.

[0117] At the beginning of the cold start, the low-voltage auxiliary battery system 2 outputs a pulse current to start supplying power to the electric heating element, which can be a PTC (Positive Temperature Coefficient) or a resistance wire. The PTC is a material or element with special resistance-temperature characteristics. In this way, the electric heating element starts to generate Joule heat under the action of the pulse current, and heats the cooling liquid in the cooling circuit.

[0118] At the same time, the low-voltage auxiliary battery system 2 starts to supply power to the coolant pump at the beginning of the cold start, so that the coolant pump drives the coolant to circulate in the stack and exchange heat with the stack. Since the coolant has been heated by the electric heating element, the heated coolant circulates in the stack, and the temperature of the stack starts to rise through heat exchange.

[0119] In addition, the Joule heat generated by the electric heating element also heats the hydrogen entering the stack through the hydrogen heater.

[0120] In this way, as the pulse current continues to be output, the coolant is sequentially heated by the electric heating element, flows into the stack after being heated, the temperature of the coolant decreases after heat exchange in the stack, the temperature of the stack rises, and then the coolant flows out of the stack, circulates through the electric heating element to be heated, and then flows into the stack after being heated. This continues to circulate, and the temperature of the stack continues to rise.

[0121] In the case where the temperature of the stack rises to the second preset temperature threshold, for example, the temperature of the stack is raised to 65°C, and the temperature of the hydrogen is also raised to 60°C or above, the low-voltage auxiliary battery system 2 starts to supply power to the air compressor, the hydrogen circulating pump, and the hydrogen storage valve, and starts to normally supply hydrogen and oxygen to the fuel cell stack. At this time, the fuel cell system 1 starts to generate electricity efficiently because the temperature of the stack is 65°C, at which the catalyst of the stack has good activity. At this time, the low-voltage auxiliary battery system 2 no longer outputs the pulse current, the electric heating element no longer heats and warms up, and the low-voltage auxiliary battery system 2 no longer supplies power to the air compressor, the coolant pump, and the hydrogen circulating pump. The air compressor, the coolant pump, and the hydrogen circulating pump start to be powered by the fuel cell stack, and the cold start is completed.

[0122] In addition, after the fuel cell system 1 is powered off, the stack also needs to be purged. During the purging process, the devices required for purging, such as the air compressor, the hydrogen circulating pump, and the coolant pump, are powered by the low-voltage auxiliary battery system 2 until the purging of the stack is completed.

[0123] Continuing from Figure 3 and in combination with Figure 4 In some exemplary embodiments, in step S211, the low-voltage auxiliary battery system 2 outputs a pulse current to the electric heating element to heat the coolant in the cooling circuit, which can include the following steps S2111-S2113.

[0124] Step S2111, obtaining the inlet temperature of the coolant entering the stack and the outlet temperature of the coolant flowing out of the stack, and calculating the temperature difference of the coolant after passing through the stack.

[0125] In step S2112, according to the temperature difference and the inlet temperature, the amplitude and the duty cycle of the pulse current output to the electric heating element are determined according to a preset determination mode.

[0126] In step S2113, the low-voltage auxiliary battery system 2 outputs the pulse current to the electric heating element according to the determined amplitude and duty cycle.

[0127] The preset determination mode includes:

[0128] When the ratio of the temperature difference to the inlet temperature is greater than a first preset ratio, the amplitude of the pulse current is determined as a first preset amplitude and the duty cycle is determined as a first preset duty cycle.

[0129] When the ratio is not greater than the first preset ratio and is greater than a second preset ratio, the amplitude of the pulse current is determined as a second preset amplitude and the duty cycle is determined as a second preset duty cycle.

[0130] When the ratio is not greater than the second preset ratio, the amplitude and the duty cycle of the pulse current are determined according to the outlet temperature and a second preset temperature threshold.

[0131] The power output by the pulse current corresponding to the first preset amplitude and the first preset duty cycle in a unit of time is greater than the power output by the pulse current corresponding to the second preset amplitude and the second preset duty cycle in a unit of time.

[0132] For example, during the cold start process, the cooling liquid is heated by the electric heating element and then flows into the electric pile, and then flows out of the electric pile after completing heat exchange in the electric pile. The temperature of the cooling liquid before flowing into the electric pile, i.e., the inlet temperature, is collected, and the temperature of the cooling liquid flowing out of the electric pile, i.e., the outlet temperature, is collected. The absolute value of the difference between the inlet temperature and the outlet temperature is calculated to obtain the temperature difference, and then the temperature difference is divided by the inlet temperature to obtain the ratio of the temperature difference to the inlet temperature, which can reflect the adjustment ability of the cooling liquid to the temperature of the electric pile. For example, the closer the ratio of the temperature difference to the inlet temperature is to 1, the greater the temperature adjustment effect of the cooling liquid on the electric pile, and the closer the ratio of the temperature difference to the inlet temperature is to 0, the smaller the temperature adjustment effect of the cooling liquid on the electric pile.

[0133] In the actual cold start process, since the initial cold start is in a low-temperature state, the maximum heating power is usually selected to heat the electric heating element at the initial cold start, i.e., the pulse current with the first preset amplitude and the first preset duty cycle is selected to heat the electric heating element, so that the electric heating element can most efficiently heat the cooling liquid.

[0134] As the temperature of the stack increases, in the first stage after the start of the cold start, the stack temperature is still low, the stack itself reaction heat is very small, and the cooling liquid has a good heating effect on the stack. Therefore, in the first stage, that is, when the ratio is greater than the first preset ratio, the low-voltage auxiliary battery system 2 is used to maintain the output of the first preset amplitude and the first preset duty cycle of the pulse current, and the pulse current is used to heat the electric heating element.

[0135] As the temperature of the stack continues to rise, the heat generated by the self-electrochemical reaction increases (for example, when the stack temperature is 20°C, hydrogen and oxygen are introduced, and the stack starts to generate heat), the temperature regulation effect of the cooling liquid on the stack gradually decreases, and the temperature rise effect of the stack itself reaction starts to increase.

[0136] Therefore, in the second stage after the start of the cold start, that is, when the ratio is not greater than the first preset ratio and is greater than the second preset ratio (wherein the second preset ratio is less than the first preset ratio), the power of the pulse current is reduced to a second preset amplitude and a second preset duty cycle.

[0137] It is worth noting that the second preset amplitude can be less than the first preset amplitude, and the second preset duty cycle can be less than the first preset duty cycle, as long as the power output by the pulse current corresponding to the first preset amplitude and the first preset duty cycle in a unit of time is greater than the power output by the pulse current corresponding to the second preset amplitude and the second preset duty cycle in a unit of time. In addition, the specific values of the first preset duty cycle, the first preset amplitude, the second preset duty cycle, and the second preset amplitude can be obtained through calibration tests, etc., and are not limited herein.

[0138] After that, in the third stage after the start of the cold start, the ratio is less than or equal to the second preset ratio, at which point the temperature regulation effect of the cooling liquid on the stack decreases to a preset degree, at which point the heating of the cooling liquid can be reduced, and the temperature rise can be mainly based on the heat generated by the stack itself, which is beneficial to reduce the amount of electricity used by the low-voltage auxiliary battery system 2 during the cold start process, prevent the amount of electricity of the low-voltage auxiliary battery system 2 from being too low, and at the same time, also have a good cold start speed.

[0139] Therefore, in the present embodiment, when the temperature difference between the inlet and outlet of the cooling liquid and the ratio of the inlet temperature is less than or equal to the second preset ratio, and the stack has started to react at this time, in order to prevent the cooling liquid temperature from being lower than the second preset temperature threshold (i.e., the second preset temperature threshold, for example, 65°C) at which the cold start ends (to prevent the cooling liquid temperature from being too low and causing the stack to start to cool down), in the third stage, the amplitude and duty cycle of the pulse current can be determined according to the second preset temperature threshold (i.e., the preset cold start end temperature, for example, 65°C) and the cooling liquid temperature at the outlet of the stack (i.e., the outlet temperature).

[0140] Specifically, the heating power of the coolant is determined with the temperature of the heated coolant (i.e. the coolant flowing into the fuel cell stack) as the lowest target of the preset cold start end temperature, and then the amplitude and duty cycle of the pulse current are determined according to the heating power of the coolant and the resistance of the electric heating element. It is worth noting that if the outlet temperature reaches or is higher than the preset cold start end temperature, the low-voltage auxiliary battery system 2 can first suspend the output of the pulse current, and in the case that the outlet temperature is less than the preset cold start end temperature, the low-voltage auxiliary battery system 2 calculates the amplitude and duty cycle of the pulse current according to the temperature difference between the outlet temperature and the preset cold start end temperature, so that the coolant is heated and the outlet temperature is raised to the preset cold start end temperature.

[0141] It is worth noting that for the above-mentioned first preset ratio and second preset ratio, those skilled in the art can select them according to the specifications of the fuel cell system 1 and its corresponding design and working requirements, etc., and they are not limited thereto, and as an example, the above-mentioned first preset ratio can be 0.4, and the above-mentioned second preset ratio can be 0.15.

[0142] In this way, until the temperature of the fuel cell stack reaches the preset cold start end temperature (i.e. the above-mentioned second preset temperature threshold), the output of the pulse current is stopped and the heating of the coolant is stopped.

[0143] Continuing from Figure 2 and shown in Figure 5 In some exemplary embodiments, in step S230, the operating power range of the fuel cell system 1 is determined according to the amount of electricity of the low-voltage auxiliary battery system 2, the operating mode of the fuel cell vehicle, and the required power of the fuel cell vehicle, which can specifically include the following steps S231-S233.

[0144] In step S231, in the case that the operating mode is the preset normal operating mode, the operating power range of the fuel cell system 1 is determined according to the amount of electricity of the low-voltage auxiliary battery system 2.

[0145] In step S232, in the case that the operating mode is the preset economic operating mode and the amount of electricity of the low-voltage auxiliary battery system 2 is lower than the first preset amount of electricity threshold, the operating power range is determined as the preset high-efficiency power range.

[0146] The first preset amount of electricity threshold can be set as the amount of electricity required to charge the low-voltage auxiliary battery system 2 in the preset economic operating mode, for example, in the case that the amount of electricity of the 48V low-voltage battery system 21 reaches 50% SOC, the 48V low-voltage battery system 21 needs to be charged, and the first preset amount of electricity threshold can be set as 50% SOC.

[0147] The preset high-efficiency power interval refers to a power range in which the fuel cell system 1 has the highest efficiency, and is usually 30%-70% of the rated power. When the operating power of the fuel cell system 1 is within the preset high-efficiency power interval, the fuel cell system 1 consumes the least amount of hydrogen for generating a unit of electric energy.

[0148] In step S233, when the operating mode is the preset sport mode, the operating power interval of the fuel cell system 1 is determined according to the demand power of the fuel cell vehicle.

[0149] Specifically, the preset normal operating mode is a default mode for daily driving of the vehicle, in which the balance between power and energy consumption needs to be considered. The preset economic operating mode is a mode with energy saving as the core target. The preset sport mode is a mode focusing on power output, which prioritizes high-power demand and is suitable for scenarios such as overtaking, climbing, and intense driving.

[0150] The driver can select the operating mode in the fuel cell vehicle according to actual needs, for example, by inputting a corresponding mode indication instruction. The controller 3 receives the mode indication instruction and adjusts the vehicle to the corresponding operating mode. In different operating modes (normal, economic, and sport), the controller 3 determines the operating power interval of the fuel cell system 1 in combination with the electric quantity of the low-voltage auxiliary battery system 2 and the demand power of the vehicle.

[0151] Specifically, in the preset normal operating mode, the low-voltage auxiliary battery system 2 is prioritized for power supply to meet the vehicle driving demand (it is worth noting that the demand power is the power required by the entire vehicle, which includes the power required for vehicle driving and the power of internal auxiliary components of the vehicle, such as lighting, etc.). In the case where the electric quantity of the low-voltage auxiliary battery system 2 is low, or the low-voltage auxiliary battery system 2 cannot meet the demand power of the vehicle driving, or in the case where the electric quantity of the low-voltage auxiliary battery system 2 is low and the low-voltage auxiliary battery system 2 also cannot meet the demand power of the vehicle driving, the fuel cell system 1 is used to output power to meet the vehicle driving demand and charge the low-voltage auxiliary battery system 2. Therefore, in step S231, in the preset normal operating mode, the operating power interval of the fuel cell system 1 can be determined according to the electric quantity of the low-voltage auxiliary battery system 2.

[0152] In the preset economic operation mode, the low-voltage auxiliary battery system 2 is preferentially used to supply power to meet the driving demand of the vehicle, and if the electric quantity of the low-voltage auxiliary battery system 2 is lower than the first preset electric quantity threshold, the fuel cell system 1 is started to supply power to meet the driving demand of the vehicle, and the low-voltage auxiliary battery system 2 is charged with the surplus. In order to ensure the energy-saving effect, in step S232, the operation power range of the fuel cell system 1 is controlled to be the preset high-efficiency power range, which is beneficial to reduce the probability of operation in other low-efficiency power ranges, improve the hydrogen-electric conversion efficiency, and reduce the waste of hydrogen.

[0153] In the preset motion mode, the fuel cell system 1 directly follows the demand power of the vehicle to operate. Specifically, in step S233, in the preset motion mode, the operation power range of the fuel cell system 1 is determined to follow the demand power of the vehicle. In addition, if the actual provided power of the fuel cell system 1 does not meet the demand power, the low-voltage auxiliary battery system 2 can make up for it to meet the demand power of the vehicle.

[0154] It is worth noting that the execution order of steps S231-S233 in the above embodiments is not limited, and the corresponding steps are executed according to the specific operation mode, which will not be described here.

[0155] Continuing to combine Figure 2 with Figure 5 and referring to Figure 6 , in some exemplary embodiments, in the preset normal operation mode, in step S240, the fuel cell system 1 and the low-voltage auxiliary battery system 2 jointly provide the demand power for the fuel cell vehicle, which can specifically include steps S241-S242.

[0156] In step S241, if the electric quantity of the low-voltage auxiliary battery system 2 is not lower than the second preset electric quantity threshold, the output power of the low-voltage auxiliary battery system 2 is controlled to be the demand power, and the fuel cell system 1 is controlled to be stopped.

[0157] Specifically, the second preset electric quantity threshold can be set according to the actual situation, for example, it can be 95% SOC, or it can be 90% SOC, which is not limited here.

[0158] In the case that the electric quantity of the low-voltage auxiliary battery system 2 is between 100%-95% (the second preset electric quantity threshold), the low-voltage auxiliary battery system 2 can provide the demand power of the vehicle. The fuel cell system 1 is in a stopped state, i.e., no gas is supplied to the stack, and the stack is temporarily suspended.

[0159] It is worth mentioning that the single cell discharge current of the low-voltage auxiliary battery system 2 has an upper limit, and it is not appropriate to output too high power, otherwise it will cause the single cell current to exceed the rated value, so that the battery cell of the low-voltage auxiliary battery system 2 is bulging or the service life of the low-voltage auxiliary battery system 2 is attenuated, etc. Therefore, if the output power upper limit value of the low-voltage auxiliary battery system 2 cannot meet the motor demand power (that is, the demand power of the vehicle running), for example, the output power upper limit value is lower than the motor demand power, steps S241 and S242 are not executed, and the motor demand power is directly provided by the fuel cell system 1.

[0160] If the battery power of the low-voltage auxiliary battery system 2 is insufficient during the process of providing the motor demand power by the fuel cell system 1, the fuel cell system 1 charges the low-voltage auxiliary battery system 2 while providing the motor demand power, until the power of the low-voltage auxiliary battery system 2 rises to not less than the second preset power threshold, and in the case of not less than the second preset power threshold, the fuel cell system 1 only needs to meet the motor demand power, and in the case of short-time acceleration of the vehicle or the fuel cell system 1 cannot supply the motor demand power, the low-voltage auxiliary battery system 2 can also supplement the remaining power.

[0161] In the case where the output power upper limit value of the low-voltage auxiliary battery system 2 is higher than the motor demand power, steps S241 and S242 are executed.

[0162] In addition, during the execution of steps S241 and S242, if it is detected that the low-voltage auxiliary battery system 2 cannot meet the motor demand power, the fuel cell system 1 provides the motor demand power, and the low-voltage auxiliary battery system 2 only needs to make up when the fuel cell system 1 cannot meet the motor demand power, and in the case where the fuel cell system 1 can meet the motor demand power, the fuel cell system 1 can also charge the low-voltage auxiliary battery system 2 to make up the power of the low-voltage auxiliary battery system 2.

[0163] Step S242, in the case where the power of the low-voltage auxiliary battery system 2 is lower than the second preset power threshold, control the fuel cell system 1 to charge the low-voltage auxiliary battery system 2 while providing the demand power for the fuel cell vehicle.

[0164] More specifically, in step S242, in the case where the power of the low-voltage auxiliary battery system 2 is lower than the second preset power threshold and not less than the third preset power threshold (for example, the power is 95%-80%), at this time, the fuel cell system 1 is controlled to operate in a preset high-efficiency power interval, and the electric energy generated by the fuel cell system 1 is preferentially supplied to the vehicle to preferentially meet the operation required by the fuel cell vehicle.

[0165] In the case that the electric energy generated by the fuel cell system 1 can meet the demand of the vehicle operation and there is excess electric energy, the low-voltage auxiliary battery system 2 is charged, and in the case that the low-voltage auxiliary battery system 2 is charged to not less than the second preset electric energy threshold, the fuel cell system 1 only needs to meet the demand of the motor to provide power, and no longer supplies power to the low-voltage auxiliary battery system 2. In the case that the electric energy generated by the fuel cell system 1 cannot meet the demand of the vehicle operation, the low-voltage auxiliary battery system 2 is used to make up, so that the fuel cell system 1 and the low-voltage auxiliary battery system 2 jointly discharge to meet the demand of the vehicle operation.

[0166] If the electric energy of the low-voltage auxiliary battery system 2 continues to decrease and decreases to less than the third preset electric energy threshold (for example, the electric energy is less than 80%), the operating power interval of the fuel cell system 1 is obtained by adjusting the preset high-efficiency power interval according to the electric energy of the low-voltage auxiliary battery system 2, and the fuel cell system 1 still takes meeting the demand of the vehicle operation as the priority, and the excess electric energy is used to charge the low-voltage auxiliary battery system 2, and the insufficient part of the electric energy is discharged by the low-voltage auxiliary battery system 2 to make up.

[0167] More specifically, the manner of obtaining the operating power interval of the fuel cell system 1 by adjusting the preset high-efficiency power interval according to the electric energy of the low-voltage auxiliary battery system 2 can specifically include: determining the electric energy interval in which the electric energy of the low-voltage auxiliary battery system 2 is located, adjusting the upper limit value and the lower limit value of the preset high-efficiency power interval according to the adjustment rule of the electric energy interval to obtain the operating power interval. For example:

[0168] In the 80%-60% electric energy interval, the electric energy of the low-voltage auxiliary battery system 2 is not in a dangerous range, and the upper limit value and the lower limit value of the preset high-efficiency power interval can be increased by a first preset power value, for example, by 10%.

[0169] In the 60%-30% electric energy interval, the electric energy of the low-voltage auxiliary battery system 2 is about to be in a dangerous range, and therefore the upper limit value and the lower limit value of the preset high-efficiency power interval can be increased by a second preset power value, for example, by 30%.

[0170] In the electric energy interval below 30%, the electric energy of the low-voltage auxiliary battery system 2 is in a dangerous range, and therefore the upper limit value and the lower limit value of the preset high-efficiency power interval can be increased by a third preset power value. In addition, the third preset power value can be increased on the basis of the demand power of the vehicle to obtain the operating power interval, so that the fuel cell system 1 can generate excess energy, and the excess energy is used to supply power to the low-voltage auxiliary battery system 2, until it is detected that the electric energy of the low-voltage auxiliary battery system 2 is higher than 30% and the time length during which the electric energy is higher than 30% reaches a preset time length, and the operating power interval is determined again according to the electric energy interval.

[0171] In this way, in the preset normal operation mode, different operation power intervals of the fuel cell can be set according to the electric quantity of the low-voltage auxiliary battery system 2, and different power supply strategies can be adopted according to the electric quantity of the low-voltage auxiliary battery system 2. When the electric quantity is sufficient, the low-voltage auxiliary battery system 2 is used to supply power alone, and when the electric quantity is insufficient, the fuel cell system 1 is used to supply power and supplement the electric quantity of the low-voltage auxiliary battery system 2. In this way, the energy utilization efficiency of the vehicle in the normal operation mode can be improved.

[0172] In addition, in the preset normal operation mode, the low-voltage auxiliary battery system 2 can be used to provide the required power alone during the starting stage after starting, and after starting is completed, the fuel cell system 1 is mainly used to provide the required power for vehicle operation. When the fuel cell system 1 is insufficient, the low-voltage auxiliary battery system 2 can be used to supplement the power gap according to the actual electric quantity, or when the fuel cell system 1 supplies too much energy, the low-voltage auxiliary battery system 2 can be charged. In this way, the probability of excessive output power of the low-voltage auxiliary battery system 2 during normal driving of the vehicle can be reduced.

[0173] Continuing to combine Figure 2 With Figure 5 As shown in FIG. 6, in some exemplary embodiments, in the preset economic operation mode, the step S240 of controlling the fuel cell system 1 and the low-voltage auxiliary battery system 2 to jointly provide the required power for the fuel cell vehicle can specifically include: when the electric quantity of the low-voltage auxiliary battery system 2 is not less than a first preset electric quantity threshold, controlling the output power of the low-voltage auxiliary battery system 2 to be the required power.

[0174] Specifically, when the electric quantity of the low-voltage auxiliary battery system 2 is not less than the first preset electric quantity threshold, the low-voltage auxiliary battery system 2 is directly controlled to output electric energy to provide the required power for vehicle driving, and the fuel cell system 1 is in a shutdown state at this time.

[0175] In addition, when the electric quantity of the low-voltage auxiliary battery system 2 is less than the first preset electric quantity threshold, the fuel cell system 1 is controlled to start, and the power thereof is in a preset high-efficiency power interval, and the required power of the vehicle is preferentially met, and the excess electric energy is used to charge the low-voltage auxiliary battery system 2 until the electric quantity of the low-voltage auxiliary battery system 2 is higher than the first preset electric quantity threshold and reaches the first preset electric quantity threshold for a preset charging duration, or until the electric quantity of the low-voltage auxiliary battery system 2 reaches 100% or reaches a preset high electric quantity threshold. Then the fuel cell system 1 is controlled to stop, and the low-voltage auxiliary battery system 2 is used to supply the required power again.

[0176] If the power output of the fuel cell system 1 cannot meet the demand power of the vehicle even if the upper limit value of the preset high-efficiency power interval is used as the power output under the condition that the electric quantity is lower than the first preset electric quantity threshold, the power output can be maintained at the upper limit value of the preset high-efficiency power interval. The remaining power can be provided by the low-voltage auxiliary battery system 2 under the condition that the electric quantity of the low-voltage auxiliary battery system 2 is not lower than the preset minimum electric quantity threshold. It should be noted that if the electric quantity of the low-voltage auxiliary battery system 2 is lower than the preset minimum electric quantity threshold, the operating power interval can be adjusted directly according to the demand power, or the fuel cell system 1 can be controlled to temporarily maintain the output at the upper limit value, and an indication information can be sent to the driver to indicate whether to adjust the operating mode. If the operating mode is adjusted, the regulation is performed according to the corresponding operating mode, otherwise the output is maintained at the upper limit value of the preset high-efficiency power interval.

[0177] In some other embodiments, under the preset economic operating mode, if the charging circuit and the discharging circuit are respectively arranged in the low-voltage auxiliary battery system 2 for the 48V low-voltage battery system 21, the fuel cell system 1 can be controlled to operate in the preset high-efficiency power interval under the condition that the electric quantity of the low-voltage auxiliary battery system 2 is lower than the first preset electric quantity threshold, and the output energy is all charged to the 48V low-voltage battery system 21 through the charging circuit. At the same time, the 48V low-voltage battery system 21 also provides the demand power required for the operation of the fuel cell vehicle through the discharging circuit. In this case, the charging or discharging state of the 48V low-voltage battery system 21 is determined by the total current direction (the current direction after the charging and discharging currents are vector superimposed).

[0178] Then, if the battery continues to be charged and discharged and still shows a discharging state, so that the electric quantity continues to decrease, the power of the fuel cell system 1 can be increased within the preset high-efficiency power interval (wherein the increased power of the fuel cell system 1 can be determined according to the electric quantity of the 48V low-voltage battery system 21. When the electric quantity of the 48V low-voltage battery system 21 is low, the power of the fuel cell system 1 should enable the 48V low-voltage battery system 21 to be charged, and should have a certain charging speed).

[0179] Then, if the power of the fuel cell system 1 is increased to the upper limit value of the preset high-efficiency power interval, the power of the fuel cell system 1 is maintained at the upper limit value under the condition that the electric quantity of the 48V low-voltage battery system 21 is not lower than the minimum electric quantity limit, and the power of the fuel cell system 1 is increased under the condition that the electric quantity of the 48V low-voltage battery system 21 is lower than the minimum electric quantity limit, so that the electric quantity of the 48V low-voltage battery system 21 is no longer decreased.

[0180] Thus, in the preset economic operation mode, the low-voltage auxiliary battery system 2 is preferentially used to provide the required power for the vehicle, and in the case of low power, the fuel cell system 1 is operated in the preset high-efficiency power range to charge the low-voltage auxiliary battery system 2 or provide the required power for the vehicle, which is beneficial to reduce the case that the fuel cell system 1 is operated in other low-efficiency power ranges to cause a large amount of hydrogen to be wasted, thereby improving the economy of the fuel cell system 1.

[0181] In some example embodiments, as shown in the above-mentioned Figure 2 In some example embodiments, as shown in the above-mentioned Figure 5 In the preset motion mode, the step S240 of controlling the fuel cell system 1 and the low-voltage auxiliary battery system 2 to jointly provide the required power for the fuel cell vehicle can specifically include: controlling the fuel cell system 1 to only provide the required power for the fuel cell vehicle. In the case that the fuel cell system 1 cannot meet the required power of the fuel cell vehicle, the low-voltage auxiliary battery system 2 is controlled to jointly provide the required power for the fuel cell vehicle.

[0182] For example, when the vehicle is in the preset motion mode, the controller 3 determines the operation power range according to the real-time required power. For example, if the required power is 100 kW and the rated power of the fuel cell is 120 kW, the operation power range can be set to 100-120 kW, and the fuel cell directly supplies power at 100 kW to meet the required power of the fuel cell vehicle. If the required power increases to 150 kW (higher than the rated power), the fuel cell is controlled to operate at the rated power of 120 kW, and the fuel cell outputs 120 kW, and the low-voltage auxiliary battery system 2 supplements 30 kW.

[0183] Thus, in the preset motion mode, the high-power output capability of the fuel cell can be preferentially utilized, and when the demand exceeds the limit, the low-voltage auxiliary battery system 2 is used to “instantly supplement power” to break through the power limit. This way can not only guarantee continuous high-power output, but also make up for the power gap through the low-voltage auxiliary battery system 2, which is beneficial to meet the demand of the driver for the dynamic performance.

[0184] In some example embodiments, as shown in the above-mentioned Figure 2 In some example embodiments, as shown in the above-mentioned Figure 5 In some example embodiments, the operation method further includes: acquiring road condition information of the fuel cell vehicle. In the case that the acquired road condition information is preset congested road condition, the low-voltage auxiliary battery system 2 is controlled to provide the required power for the fuel cell vehicle, and the fuel cell system 1 is controlled to charge the low-voltage auxiliary battery system 2 according to the remaining power of the low-voltage auxiliary battery system 2.

[0185] Specifically, the preset congestion road condition refers to a traffic congestion scenario encountered by a vehicle during driving. For example, the vehicle is considered to be in the preset congestion road condition when it is in a road condition with low speed (e.g., ≤ 20 km / h) and frequent start-stop (≥ 3 times per minute).

[0186] The road condition information can be obtained through a navigation system (real-time traffic data) carried by the vehicle, a vehicle networking information, a vehicle speed sensor, an acceleration sensor, and the like. When the road condition information meets the preset congestion condition, it is determined that the vehicle is in the preset congestion road condition. For example, when the average vehicle speed is ≤ 20 km / h and the start-stop frequency is ≥ 3 times in 5 consecutive minutes, it is determined that the vehicle is in the preset congestion road condition.

[0187] Specifically, when the controller 3 detects that the vehicle is currently in the preset congestion road condition, in order to reduce unnecessary hydrogen consumption, the controller 3 controls the low-voltage auxiliary battery system 2 to discharge to provide the required power for the fuel cell vehicle regardless of the running mode of the vehicle, until the remaining power of the low-voltage auxiliary battery system 2 is lower than the first preset congestion power threshold.

[0188] When the remaining power of the low-voltage auxiliary battery system 2 is lower than the first preset congestion power threshold, for example, the remaining power is 50%, the fuel cell system 1 is started at this time, and the fuel cell system 1 is controlled to operate in the preset high-efficiency power interval (the actual operating power of the fuel cell system 1 is greater when the remaining power of the low-voltage auxiliary battery system 2 is less), output electric energy, and the output electric energy is preferentially used to meet the required power for vehicle driving, and the excess energy is used to charge the low-voltage auxiliary battery system 2, and the low-voltage auxiliary battery system 2 suspends output of electric energy during the charging process until the power of the low-voltage auxiliary battery system 2 increases to the first preset congestion power threshold.

[0189] If the output electric energy of the fuel cell system 1 operating at the upper limit of the preset high-efficiency power interval cannot meet the required power for vehicle driving, the power of the fuel cell system 1 can be increased to charge the low-voltage auxiliary battery system 2 while meeting the required power for the vehicle. In this way, energy consumption can be minimized in the congestion road condition.

[0190] In some other embodiments, when it is detected that the vehicle is in the preset congestion road condition, the running power interval of the fuel cell system 1 in the current congestion road condition can also be determined according to the initial power of the low-voltage auxiliary battery system 2, the congestion length, and the congestion intensity (which can be determined according to the start-stop frequency, the higher the start-stop frequency, the greater the congestion intensity) when it is initially detected that the vehicle enters the preset congestion road condition.

[0191] After that, in the case that the remaining power of the low-voltage auxiliary battery system 2 is lower than the first preset congestion power threshold, the running power interval is adjusted again according to the running power interval, and the output power is preferentially used to provide the power required for vehicle driving, and the excess power is used to charge the low-voltage auxiliary battery system 2.

[0192] Specifically, if the congestion intensity, the congestion length and the initial power meet the following conditions: the congestion intensity is higher than the preset reference intensity, the congestion length is not higher than the preset reference congestion length, and the initial power is not lower than the preset reference initial power, a first preset power value is added to the upper limit value of the preset high-efficiency power interval.

[0193] Correspondingly, if the congestion length is higher than the preset reference congestion length, the congestion intensity is not higher than the preset reference intensity, and the initial power is not lower than the preset reference initial power, a second preset power value is added to the upper limit value of the preset high-efficiency power interval.

[0194] Correspondingly, if the initial power is lower than the preset reference initial power, the congestion intensity is not higher than the preset reference intensity, and the congestion length is not higher than the preset reference congestion length, a third preset power value is added to the upper limit value of the preset high-efficiency power interval.

[0195] After that, the running power interval adjusted on the basis of the preset high-efficiency power interval is used as the running power interval of the fuel cell system 1 on the current congestion road section.

[0196] It should be noted that if two or more of the congestion intensity, the congestion length and the initial power meet the corresponding conditions at the same time, for example, the congestion intensity is higher than the preset reference intensity and the congestion length is higher than the preset reference congestion length, or the congestion length is higher than the preset reference congestion length and the initial power is lower than the preset reference initial power, etc., the preset high-efficiency power interval is adjusted according to the preset stacking rule to obtain the running power interval of the current congestion road section.

[0197] In some embodiments, the preset superposition rule can comprise determining factors that meet corresponding conditions among the congestion intensity, the congestion length, and the initial electric quantity, superposing preset power values to be increased corresponding to the factors that meet the corresponding conditions, and then obtaining the preset high-efficiency power interval. For example, if the congestion intensity is higher than a preset reference intensity, the congestion length is higher than a preset reference congestion length, and the initial electric quantity is not lower than a preset reference initial electric quantity, then for the congestion intensity, a first preset power value needs to be added to the upper limit value of the preset high-efficiency power interval; for the congestion length, a second preset power value needs to be added to the upper limit value of the preset high-efficiency power interval; and for the initial electric quantity not being lower than the preset reference initial electric quantity, the preset power value to be increased corresponding to the initial electric quantity does not need to be added. Therefore, when the congestion intensity is higher than the preset reference intensity, the congestion length is higher than the preset reference congestion length, and the initial electric quantity is not lower than the preset reference initial electric quantity, the sum of the first preset power value and the second preset power value needs to be added to the upper limit value of the preset high-efficiency power interval to obtain the running power interval of the current congestion road section.

[0198] In other embodiments, the preset superposition rule can further comprise determining factors that meet corresponding conditions among the congestion intensity, the congestion length, and the initial electric quantity, and determining a maximum one of preset power values corresponding to the factors that meet the corresponding conditions, and then adding the maximum one of the preset power values to the upper limit value of the preset high-efficiency power interval to obtain the preset high-efficiency power interval. For example, if the congestion intensity is higher than a preset reference intensity, the congestion length is higher than a preset reference congestion length, and the initial electric quantity is not lower than a preset reference initial electric quantity, then for the congestion intensity, a first preset power value needs to be added to the upper limit value of the preset high-efficiency power interval; for the congestion length, a second preset power value needs to be added to the upper limit value of the preset high-efficiency power interval; and for the initial electric quantity not being lower than the preset reference initial electric quantity, the preset power value to be increased corresponding to the initial electric quantity does not need to be added. If the first preset power value is greater than the second preset power value, then the first preset power value can be added to the upper limit value of the preset high-efficiency power interval to obtain the running power interval of the current congestion road section.

[0199] In addition, in other embodiments, the preset superposition rule can further comprise adjusting the preset high-efficiency power interval according to the congestion intensity, the initial electric quantity, and the congestion length respectively to obtain three adjusted running power intervals. Then, the preset high-efficiency power interval and each of the adjusted running power intervals are respectively taken as the running power interval of the fuel cell system 1 in the current congestion road condition, the total hydrogen consumption in the current congestion road condition is simulated respectively, and the interval with the minimum total hydrogen consumption is taken as the running power interval of the current congestion road section.

[0200] Continuing with the combination Figure 2As shown in the figures, in some of the exemplary embodiments, in the case where the fuel cell system 1 fails to operate, the fuel cell vehicle can also be powered by the low-voltage auxiliary battery system 2 to assist the vehicle in driving. Specifically, the method of operation can further include: obtaining fault information of the stack; in the case where a preset fault occurs in the stack, controlling the low-voltage auxiliary battery system 2 to power the fuel cell vehicle according to a preset power supply strategy.

[0201] Specifically, the stack fault information refers to various parameter data and state signals reflecting abnormal operation of the fuel cell stack, including voltage, current, temperature, gas pressure, leakage detection, and other information or alarm signals.

[0202] The preset fault is a fault that causes the fuel cell system 1 to fail to normally output power. In the case of a preset fault, the fuel cell system 1 cannot output power or should be shut down. For example, the stack is severely under-voltage, or there is a hydrogen leak, or the stack is overheated.

[0203] Specifically, in the case of a preset fault, the stack of the fuel cell cannot output power, and the low-voltage auxiliary battery system 2 becomes an independent power source, providing power to the vehicle's key systems such as the drive motor, braking system, safety system (such as a hydrogen leak sensor), basic lighting system, and communication system (for calling for rescue) through the 48V low-voltage battery system 21 and the bidirectional DC / DC converter 22. Specifically, for key systems that directly use 48V low-voltage direct current, the 48V low-voltage battery system 21 can directly output low-voltage direct current for power supply. For key systems that require high-voltage power supply, the 48V low-voltage battery system 21 can output low-voltage direct current, which is then converted to high-voltage direct current by the bidirectional DC / DC converter 22, and the high-voltage direct current is used to power such key systems. In this way, through the low-voltage auxiliary battery system 2, in the case of a preset fault in the vehicle's fuel cell system 1, power can also be provided to the vehicle's key systems to ensure that the vehicle can safely pull over, execute safety protocols (such as enabling the action of emptying the hydrogen in the fuel cell stack), and maintain communication with the outside world to ensure the safety of the passengers.

[0204] More specifically, the preset power supply strategy can include: within a preset initial time period after the fault is triggered, prioritizing the power supply of the vehicle's key control systems, safety systems, basic lighting, and communication systems, and temporarily shutting down unnecessary devices such as air conditioning and seat heating to reduce power consumption. At the same time, limit the maximum output power of the fuel cell system 1 to avoid large current discharge of the 48V low-voltage battery system 21. Then calculate the remaining battery range (range = current power × battery capacity / average power consumption) in real time, and in the case where the range is less than a preset range, turn off the lights, multimedia, and other devices, and only maintain the power supply of the key control systems such as driving and steering braking to prioritize safe parking.

[0205] It is worth mentioning that the bidirectional DC / DC converter 22 of the embodiment can convert the low-voltage direct current output by the 48V low-voltage battery system 21 into high-voltage direct current. When the fuel cell system 1 normally works to charge the 48V low-voltage battery system 21, the high-voltage direct current output by the fuel cell system 1 can be converted into low-voltage direct current by the bidirectional DC / DC converter 22 to charge the 48V low-voltage battery system 21.

[0206] It is worth mentioning that, based on the above exemplary embodiments, as a preferred embodiment, the operation method of the fuel cell vehicle can include the following steps:

[0207] When the fuel cell vehicle is cold started, the low-voltage auxiliary battery system 2 outputs a pulse current to start supplying power to the electric heating element. The electric heating element starts to generate Joule heat under the action of the pulse current and heats the cooling liquid in the cooling loop. At the same time, the low-voltage auxiliary battery system 2 starts to supply power to the cooling liquid pump, so that the cooling liquid pump drives the cooling liquid to circulate in the stack and exchange heat with the stack to warm up the stack.

[0208] At the same time, the Joule heat generated by the electric heating element also heats the hydrogen entering the stack through the hydrogen heater.

[0209] When the stack temperature rises to a preset cold start end temperature, for example, the stack temperature is raised to 65℃, and the temperature of the hydrogen is also raised to 60℃ or above, the low-voltage auxiliary battery system 2 starts to supply power to the air compressor, successfully starts the air compressor pump, and starts to normally supply hydrogen and oxygen to the fuel cell stack. The stack temperature is 65℃, at which the catalyst of the stack has good activity and starts to generate electricity efficiently. At this time, the low-voltage auxiliary battery system 2 no longer outputs a pulse current, the electric heating element no longer heats and warms up, and the air compressor, the cooling liquid pump, and the hydrogen circulation pump are no longer supplied with power by the low-voltage auxiliary battery system 2. The air compressor, the cooling liquid pump, and the hydrogen circulation pump start to be supplied with power by the fuel cell stack, and the cold start is completed.

[0210] After that, during the driving of the vehicle, the power output strategy is determined according to the normal, economic, and sport modes, the fuel cell operation range is determined in combination with the power of the low-voltage auxiliary battery system 2 and the required power, and the fuel cell is controlled to maintain in the operation power range to output power to cooperate with the low-voltage auxiliary battery system 2 to supply power.

[0211] In the normal mode, if the battery can meet the motor demand power (i.e. the demand power of the vehicle), the battery alone provides power, if the battery cannot meet the motor demand power, or the battery power is lower than the set value, or the battery cannot meet the motor demand power and the battery power is also lower than the set value, the fuel cell system 1 starts to provide the motor demand power, and if the battery power is insufficient, the battery is charged, and if the battery power is above the second preset power threshold, the fuel cell system 1 only needs to meet the motor demand to provide the motor demand power; the low-voltage auxiliary battery system 2 is mainly responsible for driving, and when the low-voltage auxiliary battery system 2 has low power, the fuel cell system 1 drives and charges efficiently; in the sports mode, the fuel cell system 1 is the main power source, and the low-voltage auxiliary battery system 2 supplements the power gap, so as to realize that the low-voltage auxiliary battery system 2 cooperates with the fuel cell system 1 to meet the power required for the vehicle operation.

[0212] After the vehicle arrives at the destination and stops, the fuel cell system 1 is powered off, at this time, the stack needs to be purged, and in the purging process, the air compressor, the hydrogen circulating pump and the cooling liquid pump and other purging power supply equipment are powered by the low-voltage auxiliary battery system 2 until the purging of the stack is completed and the power supply is ended.

[0213] The second aspect of the present application provides a fuel cell vehicle, which refers to Figure 1 The fuel cell vehicle specifically includes a fuel cell system 1, a low-voltage auxiliary battery system 2 and a controller 3.

[0214] The controller 3 is connected with the fuel cell system 1 and the low-voltage auxiliary battery system 2, and the controller 3 includes a processor, a memory, and a computer program stored in the memory; when the computer program is executed by the processor, the controller 3 realizes the operation method of the fuel cell vehicle of the above-mentioned first aspect of the embodiment.

[0215] Specifically, referring to the description in the above method embodiment, similarly, the fuel cell system 1 of the present embodiment includes a stack, and the low-voltage auxiliary battery system 2 includes a 48V low-voltage battery system 21 formed by two 24V storage batteries in series and a bidirectional DC / DC converter 22, wherein the 48V low-voltage battery system 21 and the bidirectional DC / DC converter 22 are connected in series. Similarly, the fuel cell vehicle of the present embodiment can also include an on-board hydrogen storage system composed of a plurality of hydrogen storage bottles, an electric motor and a transmission, which will not be described here.

[0216] The fuel cell vehicle of the present embodiment, by using the low-voltage auxiliary battery system 2 to replace the traditional high-voltage battery system, is conducive to reducing the weight and manufacturing cost of the fuel cell vehicle, and can also improve the safety of the vehicle.

[0217] The above merely describes some embodiments of the present application, and is not intended to limit the present application, and the technical features or structures in the different embodiments above can be combined as needed to form other specific technical solutions. Various changes and modifications can be made by those skilled in the art based on the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method of operating a fuel cell vehicle, characterized by, The fuel cell vehicle comprises a fuel cell system (1) and a low-voltage auxiliary battery system (2), and the operation method comprises: When the fuel cell vehicle is cold-started, the low-voltage auxiliary battery system (2) is controlled to supply power to the fuel cell system (1) to warm up the stack in the fuel cell system (1) and until the fuel cell vehicle is cold-started; During the operation after the fuel cell vehicle is started, the power output strategy of the fuel cell system (1) is determined according to the operation mode of the fuel cell vehicle, wherein the power output strategy represents the distribution rule of the output power of the fuel cell system (1); According to the power of the low-voltage auxiliary battery system (2), the operation mode of the fuel cell vehicle, and the demand power of the fuel cell vehicle, the operation power interval of the fuel cell system (1) is determined; The output power of the fuel cell system (1) is controlled to maintain in the operation power interval, and the fuel cell system (1) and the low-voltage auxiliary battery system (2) are controlled to jointly provide the demand power of the fuel cell vehicle according to the determined power output strategy; The fuel cell system (1) comprises a cooling circuit connected to the stack, and an electric heating element is arranged in the cooling circuit; When the fuel cell vehicle is cold-started, the control of the low-voltage auxiliary battery system (2) to supply power to the fuel cell system (1) to warm up the stack in the fuel cell system (1) comprises: The low-voltage auxiliary battery system (2) is controlled to supply power to the cooling liquid pump in the cooling circuit to start the cooling circuit, and the low-voltage auxiliary battery system (2) is controlled to output pulse current to the electric heating element to heat the cooling liquid in the cooling circuit; When the temperature of the stack reaches a first preset temperature threshold, the low-voltage auxiliary battery system (2) is controlled to supply power to the air compressor in the fuel cell system (1); When the temperature of the stack reaches a second preset temperature threshold, the low-voltage auxiliary battery system (2) is controlled to stop supplying power to the fuel cell system (1); The control of the low-voltage auxiliary battery system (2) to output pulse current to the electric heating element to heat the cooling liquid in the cooling circuit comprises: The inlet temperature of the cooling liquid entering the stack and the outlet temperature of the cooling liquid flowing out of the stack are obtained, and the temperature difference of the cooling liquid after passing through the stack is calculated; According to the temperature difference and the inlet temperature, the amplitude and duty cycle of the pulse current output to the electric heating element are determined according to a preset determination method; The low-voltage auxiliary battery system (2) outputs pulse current to the electric heating element according to the determined amplitude and duty cycle; The preset determination method comprises: When the ratio of the temperature difference to the inlet temperature is greater than a first preset ratio, the amplitude of the pulse current is determined as a first preset amplitude, and the duty cycle is determined as a first preset duty cycle. In a case where the ratio is not greater than the first preset ratio and is greater than a second preset ratio, the amplitude of the pulse current is determined as a second preset amplitude and the duty cycle is determined as a second preset duty cycle; In a case where the ratio is not greater than the second preset ratio, the amplitude and the duty cycle of the pulse current are determined according to the liquid outlet temperature and the second preset temperature threshold; The pulse current corresponding to the first preset amplitude and the first preset duty cycle outputs a power in a unit time, which is greater than a power in a unit time output by a pulse current corresponding to the second preset amplitude and the second preset duty cycle.

2. The method of operating a fuel cell vehicle according to claim 1, characterized by, The determination of the operation power range of the fuel cell system (1) according to the electric quantity of the low-voltage auxiliary battery system (2), the operation mode of the fuel cell vehicle, and the demand power of the fuel cell vehicle includes: In a case where the operation mode is a preset normal operation mode, the operation power range of the fuel cell system (1) is determined according to the electric quantity of the low-voltage auxiliary battery system (2); In a case where the operation mode is a preset economic operation mode and the electric quantity of the low-voltage auxiliary battery system (2) is lower than a first preset electric quantity threshold, the operation power range is determined as a preset high-efficiency power range; In a case where the operation mode is a preset motion mode, the operation power range of the fuel cell system (1) is determined according to the demand power of the fuel cell vehicle.

3. The method of operating a fuel cell vehicle according to claim 2, characterized by, In a case where the operation mode is the preset normal operation mode, the control of the fuel cell system (1) and the low-voltage auxiliary battery system (2) to jointly provide the demand power for the fuel cell vehicle includes: In a case where the electric quantity of the low-voltage auxiliary battery system (2) is not lower than a second preset electric quantity threshold, the output power of the low-voltage auxiliary battery system (2) is controlled to be the demand power, and the fuel cell system (1) is controlled to be shut down; In a case where the electric quantity of the low-voltage auxiliary battery system (2) is lower than the second preset electric quantity threshold, the fuel cell system (1) is controlled to provide the demand power for the fuel cell vehicle while charging the low-voltage auxiliary battery system (2).

4. The method of operating a fuel cell vehicle according to claim 2, characterized by, In a case where the operation mode is the preset economic operation mode, the control of the fuel cell system (1) and the low-voltage auxiliary battery system (2) to jointly provide the demand power for the fuel cell vehicle includes: In a case where the electric quantity of the low-voltage auxiliary battery system (2) is not lower than the first preset electric quantity threshold, the output power of the low-voltage auxiliary battery system (2) is controlled to be the demand power.

5. The method of operating a fuel cell vehicle according to claim 2, characterized by, In a case where the operation mode is the preset motion mode, the control of the fuel cell system (1) and the low-voltage auxiliary battery system (2) to jointly provide the demand power for the fuel cell vehicle includes: The fuel cell system (1) is controlled to provide only the demand power for the fuel cell vehicle; In the case that the fuel cell system (1) cannot meet the demand power of the fuel cell vehicle, the low-voltage auxiliary battery system (2) is controlled to provide the demand power for the fuel cell vehicle together.

6. The method of operating a fuel cell vehicle according to any one of claims 3 to 5, characterized by, The operation method further comprises: acquiring road condition information of the fuel cell vehicle; in the case that the acquired road condition information is preset congestion road condition, the low-voltage auxiliary battery system (2) is controlled to provide demand power for the fuel cell vehicle, and the fuel cell system (1) is controlled to charge the low-voltage auxiliary battery system (2) according to the remaining power of the low-voltage auxiliary battery system (2).

7. The method of operating a fuel cell vehicle according to claim 1, characterized by, The operation method further comprises: acquiring fault information of the fuel cell stack; in the case that the fuel cell stack has preset fault, the low-voltage auxiliary battery system (2) is controlled to supply power to the fuel cell vehicle according to preset power supply strategy.

8. A fuel cell vehicle, characterized in that: comprising a fuel cell system (1), a low-voltage auxiliary battery system (2), and a controller (3); the controller (3) is connected with the fuel cell system (1) and the low-voltage auxiliary battery system (2), and the controller (3) comprises a processor, a memory, and a computer program stored in the memory; when the computer program is executed by the processor, the controller (3) executes the operation method of the fuel cell vehicle according to any one of claims 1-7.

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