A hydrogen fuel cell vehicle starting control method

Abstract

The present invention discloses a hydrogen fuel cell vehicle starting control method, which includes: powering on and waking up the vehicle control unit (VCU) and performing a self-test; turning on the ignition switch to check whether a high-voltage condition is met, if the high-voltage condition is not met, the instrument displays a fault message, and if the high-voltage condition is met, the instrument displays a high-voltage success message; pressing a hybrid switch to enter a hydrogen fuel cell starting mode, and not pressing the switch to enter a pure electric driving mode; judging whether the power battery cell temperature is greater than T0, and if it is greater than or equal to T0, the hydrogen fuel cell enters a normal-temperature starting mode, and if it is less than T0, the hydrogen fuel cell enters a low-temperature starting mode; T0 is a preset temperature value; the present application improves the hydrogen fuel cell vehicle starting control method to make the hydrogen fuel cell vehicle starting control method more efficient and reliable, and can meet the starting requirements of hydrogen fuel cell vehicles under various temperature environments, and does not charge the power battery after starting, which does not affect the performance and service life of the power battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen fuel cell systems for new energy vehicles, and specifically relates to a starting control method for a hydrogen fuel cell vehicle. Background Art

[0002] Hydrogen has the highest combustion energy density of all fossil fuels, chemical fuels, and biofuels, excluding nuclear fuel. Hydrogen not only has a high thermal conductivity, but also produces only water as a combustion product. It is an important, high-quality, renewable secondary energy source that can replace gasoline and diesel for rapid ignition and starting of vehicles and other power tools, while also meeting societal and environmental demands for energy conservation and carbon reduction, and lowering travel costs. The cost of hydrogen fuel applications is expected to decline further. Combined with advancements in hydrogen fuel vehicle manufacturing technology, this will continue to drive down the cost of hydrogen fuel vehicle applications, giving hydrogen fuel vehicles a promising future.

[0003] Hydrogen fuel cells are energy conversion devices that convert the chemical energy in hydrogen directly into electrical energy. They are key to realizing hydrogen energy applications. Compared to internal combustion engines, hydrogen fuel cells offer lower environmental pollution, greater flexibility, greater reliability, and higher conversion efficiency. However, despite the broad market potential of hydrogen fuel cell vehicles, the technology still faces challenges, particularly the difficulty of starting in low-temperature conditions.

[0004] Hydrogen fuel cells are difficult to start in low-temperature environments because low temperatures affect the chemical reaction rate within the battery, resulting in reduced starting performance. This problem limits the use of hydrogen fuel cell vehicles in low-temperature environments and, in turn, hinders their widespread adoption. Although my country's hydrogen fuel cell vehicle industry is currently experiencing rapid development and the market size is continuously expanding, further technological breakthroughs and innovations are needed to solve the low-temperature starting problem. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a hydrogen fuel cell vehicle starting control method, which has the advantages of solving the problem of smooth starting of hydrogen fuel cell vehicles under various ambient temperatures, ensuring the normal operation of various systems without faults after the hydrogen fuel cell is started, and extending the service life of various systems.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: a hydrogen fuel cell vehicle starting control method, the control method comprising:

[0007] S1: Power on and wake up the vehicle control unit (VCU) and perform self-test;

[0008] S2: Turn on the ignition switch and check whether the high voltage conditions are met. If the high voltage conditions are not met, the instrument will display a fault message. If the high voltage conditions are met, the instrument will display a high voltage success message.

[0009] S3: Press the hybrid switch to enter the hydrogen fuel cell start mode, and if not pressed, it enters the pure electric driving mode;

[0010] S4: Determine whether the power battery cell temperature is greater than T0. If it is greater than or equal to T0, the hydrogen fuel cell enters the normal temperature start mode; if it is less than T0, the hydrogen fuel cell enters the low temperature start mode; T0 is a preset temperature value;

[0011] The normal temperature start-up mode of the hydrogen fuel cell includes the following steps:

[0012] S41: Entering the fuel cell normal temperature starting mode;

[0013] S42: Collect the power battery discharge power P 放 , Hydrogen fuel cell starting power P 起 Plus vehicle accessories power P 附 And judge, if P 放 <P 起 +P 附 , then the instrument will issue a prompt to charge first and then start the fuel cell. If P 放 >P 起 +P 附 , then proceed to step S43;

[0014] S43: Check whether the power battery's SOC is higher than 70%. If higher than 70%, operate in pure electric mode to reduce the SOC. After the SOC is lower than 70%, the fuel cell system is allowed to start.

[0015] S44: After receiving the start command, the fuel cell system FCU performs a system self-check. If there is no fault, the start process is executed and the system enters the idle operation state;

[0016] The hydrogen fuel cell low temperature start mode includes the following steps:

[0017] S45: Collect the power battery discharge power P 放 , Hydrogen fuel cell starting power P 起 Plus vehicle accessories power P 附 And judge, if P 放 <P 起 +P 附 , then the instrument will issue a prompt to charge first and then start the fuel cell. If P 放 >P 起 +P 附 , then proceed to step S46;

[0018] S46: The VCU forcibly shuts down accessories such as the heating system APTC and the battery heating device WPTC to ensure that the power battery has sufficient discharge power for the fuel cell to start;

[0019] S47: Check whether the power battery's SOC is higher than 80%. If higher than 80%, operate in pure electric mode to reduce the SOC. After the SOC is lower than 80%, the fuel cell system is allowed to start.

[0020] S48: After receiving the start command, the fuel cell system FCU performs a system self-check. If there is no fault, the start process is executed.

[0021] Normal hydrogen fuel cell startup is to calculate the power balance. This invention takes into account factors such as power involved in the entire startup process, power battery SOC, battery charging and discharging performance degradation at low temperatures, and avoids the problem of frequent starting and stopping due to excessive SOC when charging the battery after the stack is stacked.

[0022] Hydrogen fuel cell vehicles (FCVs) have a complex system structure. In addition to the conventional three-electric system (motor, electronic control, and battery) of pure electric vehicles, their powertrain also includes a hydrogen fuel cell system (hydrogen-oxygen reactor system), a hydrogen supply system, a fuel cell cooling system, and a power battery heating device. At low temperatures, the electrolyte thickens, slowing aluminum ion movement and increasing internal resistance, leading to decreased charge and discharge performance and capacity. When the cell temperature is between 0°C and 10°C, the battery cannot charge. Forced charging can cause a chemical reaction that forms lithium crystals, reducing lithium ions and shortening the power battery's capacity and lifespan. To ensure battery performance and lifespan, FCVs must ensure that the power battery is not continuously charged after starting in low temperatures. The primary concern with cold-temperature starting is the degradation of the power battery's charge and discharge performance. To ensure that the power battery discharge power meets the fuel cell starting requirements while maintaining continuous power output after the hydrogen fuel cell is started, an accessory is required to absorb the fuel cell's output power.

[0023] Preferably, the vehicle control unit VCU communicates with the power battery control system BMS, the hydrogen fuel cell control unit FCU, the instrument IC, the power battery heating device WPTC and the warm air system APTC through the vehicle CAN bus, and the current physical quantities and working status collected by each system are sent to the vehicle CAN bus through messages for use by related systems.

[0024] Preferably, the vehicle control unit VCU collects the power battery's allowable charging power, allowable discharging power, cell temperature, charge capacity ratio SOC, fault information, fuel cell system starting power consumption, discharge power, working status, fault information, power mode switch status, and working status of each accessory. Through energy balance calculation, the working status of each component is controlled in a timely manner to ensure that the fuel cell system can start smoothly at low temperatures, and that each component can work normally without fault after starting, thereby ensuring the safety and service life of each system of the vehicle.

[0025] Preferably, the energy balance calculation formula is: ,in, Input energy to the fuel, For electrical output energy, is the heat output energy, For energy loss.

[0026] Preferably, the power battery control system BMS collects and sends out voltage, current, and allowable discharge power P 放 , allowable charging power P 充 , battery cell temperature T 芯 , charge capacity SOC and the status and fault information of each relay, and execute each instruction issued by the vehicle control unit VCU according to the set process.

[0027] Preferably, the hydrogen fuel cell control unit FCU independently completes the data collection, working state control and fault diagnosis of the hydrogen fuel cell, and its start, stop and power request are carried out according to the instructions of the vehicle control unit VCU.

[0028] Preferably, after the fuel cell system FCU is successfully started, the vehicle control unit VCU sets the power battery allowable charging power P 充 and fuel cell output power P 出 For comparison, if P 充 Less than P 出 , forcefully open all accessories of the vehicle to prevent the fuel cell from outputting too much power to charge the power battery and reporting an overcharge fault.

[0029] Preferably, the hydrogen fuel cell vehicle starting control method is divided into a normal temperature starting mode and a low temperature starting mode. Before starting the hydrogen fuel cell, the entire vehicle must first perform a high-voltage process.

[0030] Preferably, when the power battery cell temperature is low and the SOC is low and the discharge power does not meet the hydrogen fuel cell startup requirements, the vehicle control unit VCU will send a prompt to remind the driver to charge in pure electric mode before starting the hydrogen fuel cell. When the power battery SOC is too high, the VCU will prohibit the fuel cell from starting.

[0031] The hydrogen fuel cell vehicle's low-temperature starting system features two modes: pure electric power and hybrid operation. Drivers can operate the system based on the usage scenario and prompts. When the vehicle needs to be parked in a closed or semi-closed parking lot, pure electric mode is selected for entry or exit. Hybrid mode is selected for other scenarios. The vehicle control unit (VCU) automatically controls the distribution of hydrogen fuel or power battery energy. When the power battery cell temperature is low and the SOC is low, the discharge power does not meet the hydrogen fuel cell startup requirements, the VCU will send a prompt, prompting the driver to charge in pure electric mode before starting the hydrogen fuel cell. When the power battery SOC is too high, the VCU will prohibit the fuel cell from starting to avoid frequent fuel cell starts and stops and overcharging of the power battery.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] By improving the starting control method of hydrogen fuel cell vehicles, the present application can make the starting control method of hydrogen fuel cell vehicles more efficient and reliable, and can meet the starting requirements of hydrogen fuel cell vehicles under various temperature environments. The power battery will not be charged after starting, which will not affect the performance and service life of the power battery. The fuel cell can be prohibited from starting when the power battery is insufficient, avoiding damage to the fuel cell due to unsuccessful starting and affecting its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the vehicle network architecture of the present invention.

[0035] Figure 2 It is a schematic diagram of the high-voltage process during starting.

[0036] Figure 3 It is a flow chart of the normal temperature starting control method.

[0037] Figure 4 It is a flow chart of the low-temperature starting control method. DETAILED DESCRIPTION

[0038] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] The present invention provides a technical solution: a hydrogen fuel cell vehicle starting control method, the control method comprising:

[0041] S21: Power on and wake up the VCU and perform self-test;

[0042] S22: Turn on the ignition switch and check whether the high voltage conditions are met. If the high voltage conditions are not met, the instrument will display a fault message. If the high voltage conditions are met, the instrument will display a high voltage success message.

[0043] S25: Press the hybrid switch to enter the fuel cell start mode S261; if not pressed, enter the pure electric driving mode S262;

[0044] S27: Determine whether the power battery cell temperature is greater than T0. If it is greater than or equal to T0, the fuel cell enters the normal temperature start-up mode S281. If it is less than T0, the fuel cell enters the low temperature start-up mode S282.

[0045] Among them, the basic network architecture of the vehicle is as follows Figure 1 As shown in the figure, the main network node units include the power battery control system BMS1, the vehicle control unit VCU2, the hydrogen fuel cell control unit FCU3, the instrument IC4, the power battery heating device WPTC5, the warm air system APTC6, and other components such as the remote monitoring system and the gateway.

[0046] The mode switch 7 is directly connected to the VCU via a hardwire. The current physical quantities and working status information collected by each system are sent to the vehicle CAN bus through messages for use by related systems. The power battery control system BMS1 collects and sends information such as voltage, current, allowable discharge power Pdischarge, allowable charging power Pcharge, battery cell temperature Tcore, charge capacity SOC, the status of each relay inside it, and faults, and executes each instruction issued by the vehicle control unit VCU2 according to the set process. The power battery allowable charging power P 充 The lowest temperature Tcharge is determined by its battery cell material and production process. Usually, the lowest temperature T0 allowed for charging of lithium batteries is between 0℃ and 10℃. The allowable discharge power Pdischarge of power batteries decreases with the decrease of temperature and SOC. Therefore, in the low temperature and low SOC state, in order to protect the power battery and extend the service life of the power battery, it is necessary to make different control strategies for the start of hydrogen fuel cell vehicles according to different temperatures. The hydrogen fuel cell control unit FCU3 is a relatively independent system. The data acquisition, working status control, fault diagnosis, etc. of the hydrogen fuel cell itself are all completed independently by itself. Its start and stop and power request must obey the instructions of the vehicle control unit VCU. After the development of the hydrogen fuel cell is completed, the stable output power P after its start will be tested through experimental data. 稳This value confirms that the fuel cell can operate independently, start successfully, and reach the idle operation state. In this state, the fuel cell will output a rated idle power P 怠 These data and status information will be sent to the vehicle CAN bus through its control system FCU. Instrument IC4 mainly receives fault information and various prompt messages sent by each controller to guide users to use the car correctly and reasonably.

[0047] The power battery heating device WPTC5 heats the power battery to room temperature when the power battery cell temperature is low, thereby improving the battery's charge and discharge performance. The air heater APTC6 provides heating for the driver's cab. Both WPTC and APTC are controlled by the vehicle control unit (VCU). This accessory system is one of the accessories that consumes the power generated by the fuel cell after startup at low temperatures. In low-temperature startup mode, if the power battery's discharge power (Pdis) cannot meet the hydrogen fuel cell system's starting power (Pstart) and the accessory operating power (Paccess), the VCU will issue a command to forcibly disable accessory operation. After the hydrogen fuel cell is successfully started and the power battery cannot support continuous charging, the accessories are forcibly activated to consume the fuel cell's power. The mode switch 7 has two states: pressed for hybrid mode and released for pure electric mode. The VCU determines the driver's vehicle mode by receiving the on / off signal from this switch. During the entire fuel cell startup process, the vehicle control unit (VCU2) serves as the master controller, collecting startup information from each system, determining startup conditions, and controlling each system to execute corresponding actions according to the corresponding timing.

[0048] The starting control methods of hydrogen fuel cell vehicles are divided into normal temperature starting mode and low temperature starting mode. Regardless of normal temperature starting or low temperature starting, the entire vehicle must first perform the high-voltage process before starting the hydrogen fuel cell.

[0049] like Figure 2As shown, when the driver turns the key to the ON position to power on, the vehicle starts to execute S21. After the VCU and each controller are awakened, they first perform a power-on self-test. If there is a fault in the control system, the fault information will be displayed on the instrument. After the self-test passes, the VCU is in standby state; when the Start signal of the ignition switch S22 is received, the vehicle proceeds to the S23 high-voltage process. The VCU checks whether the vehicle meets the high-voltage conditions according to the process. If the conditions are met, it will execute S241 to close the main positive and negative relays of the power battery and send a high-voltage success mark "Redey" to the instrument. Otherwise, it will execute S242 to send a system fault message to the instrument. After the high voltage is successful, the VCU executes S25 checks whether the mode switch is pressed. If not, S262 is executed to drive in pure electric mode. At this time, the vehicle can drive with the power battery as the power. If the mode switch is pressed, S261 fuel cell system start mode process is executed. After officially entering the fuel cell start mode, the VCU will read the current power battery cell temperature T core sent by the power battery BMS on the bus through S27, and compare it with the power battery allowable charging temperature T0. If T core ≥ T0, S281 fuel cell normal temperature start mode is executed, otherwise S282 fuel cell low temperature start mode is executed. At this point, the vehicle completes the high-voltage process and determines the current start mode of the fuel cell.

[0050] like Figure 3The figure shows the control flow diagram of the fuel cell normal temperature start mode. When the VCU determines that the power battery cell temperature T core is higher than its minimum allowable charging temperature value T0, it enters the fuel cell normal temperature start mode S31. Even if the power battery charge and discharge performance is very good at normal temperature, in order to ensure successful starting, the VCU will execute S32 to perform power battery discharge power P discharge > hydrogen fuel cell starting power P start + vehicle accessory power P attachment. If the power battery discharge power is insufficient, S332 will be executed directly, and a "please charge before starting the fuel cell" prompt will be issued to the instrument. Otherwise, S331 will be executed to check whether the SOC of the power battery is higher than 70% to avoid overcharging the power battery after starting the fuel cell due to excessively high power battery SOC and frequent starting and stopping of the fuel cell. If the SOC is higher than 70%, S342 will be executed to operate in pure electric mode to reduce the SOC of the power battery until the SOC is lower than 70%. Line S341 allows the fuel cell system to start. After receiving the start command, the fuel cell system FCU in S35 first performs a system self-check to determine whether there is a fault in the fuel cell system. If there is a fault that affects normal operation, S362 is executed to terminate the fuel cell system start process and send a fault message to the instrument. If there is no fault in the FCU system, S361 FCU start process is executed (controls the various components of the fuel cell system to work according to the start process sequence). After the start process of S37 FCU is executed without any fault, the system enters the idle operation condition. At this time, the idle power P idle generated by the fuel cell is consumed by the vehicle accessories in S38 or charges the power battery. All systems of the vehicle are in normal working condition and there is no risk of any energy imbalance in the system. If there is any fault in the operation of each system at this time, VCU will perform corresponding operations according to the level of the fault. At this point, the fuel cell normal temperature start process ends.

[0051] like Figure 4 The figure shows the control flow of the fuel cell low temperature start mode. When the VCU determines that the power battery cell temperature T core is lower than its minimum allowable charging temperature value T0, it enters the fuel cell low temperature start mode S41, and the VCU executes S42 to discharge the power battery P 放>The starting power of the hydrogen fuel cell \(P_{start}\) + the power of vehicle accessories \(P_{accessory}\). If the discharge power of the power battery is insufficient, it will directly execute the comparison of \(P_{discharge}\) (the discharge power of the power battery) > \(P_{start}\) in S432. If the starting power of the power battery \(P_{discharge}\) is less than the starting power of the fuel cell \(P_{start}\), it will execute S421 to send a prompt of "Please charge the battery first before starting the fuel cell" to the instrument. Otherwise, it will execute S422. The VCU forcibly closes accessories such as the warm air APTC and the battery heating device WPTC to ensure that the power battery has sufficient discharge power for the fuel cell to start. After confirming that the accessories are closed, it will execute S44 to check whether the SOC of the power battery is higher than 80%. To avoid overcharging the power battery and frequent start and stop of the fuel cell due to too high SOC of the power battery when starting the fuel cell. If the SOC is higher than 80%, it will execute S442 to run in pure electric mode to reduce the SOC of the power battery until the SOC is lower than 80%, and then execute S441 to allow the fuel cell system to start.

[0052] The vehicle control unit (VCU) collects the allowable charging power, allowable discharge power, cell temperature, state of charge ratio (SOC), fault information of the power battery, the power consumption, discharge power, working state, fault information of the fuel cell system startup, the power mode switch state, and the working state of each accessory. Through energy balance calculation, it timely controls the working state of each component to ensure that the fuel cell system can start smoothly at low temperature, and each component can work normally without faults after startup, ensuring the safety and service life of each system of the vehicle.

[0053] The energy balance calculation formula is: , where is the fuel input energy, is the electrical output energy, is the heat output energy, is the energy loss.

[0054] After receiving the startup command, the fuel cell system (FCU) first performs a system self-check to determine whether there are faults in the fuel cell system. If there are faults that affect normal operation, it will execute S462 to abort the fuel cell system startup process and send fault information to the instrument. If the FCU system has no faults, it will execute S361, the FCU startup process. During the startup process of the fuel cell, the VCU needs to repeatedly execute S47: the output power of the fuel cell \(P_{output}\geq\) the stable output power of the fuel cell \(P\) 稳, by detecting the magnitude of the output power of the fuel cell, it is determined whether the fuel cell has started successfully. After the fuel cell starts successfully, execute S48, the allowable charging power P_charging of the power battery ≥ the output power P_output of the fuel cell. If P_charging ≥ P_output, then S492 allows the vehicle accessories to work as needed. Otherwise, S49 forcibly turns on all vehicle accessories and makes the accessories work at the rated power to avoid overcharging faults caused by the output power of the fuel cell charging the power battery after startup and affecting the service life of the power battery. After the VCU processes the working state of the vehicle accessories, it will execute S4A, the output power P_output of the fuel cell ≥ the idle power P_idle of the fuel cell to determine whether the fuel cell is in the idle running state. If the output power P_output of the fuel cell is smaller than the idle power P_idle at this time, the VCU will re-execute S47 until the fuel cell system executes S4B2 to enter the idle running state. During idle running, the VCU will execute S4C, the temperature T_core of the power battery cell ≥ the minimum allowable charging temperature T0. If the temperature T_core of the power battery cell is lower than the minimum allowable charging temperature T0 of the power battery, the VCU will re-execute S48. Otherwise, execute S4D to turn off the vehicle accessories.至此, the fuel cell low-temperature startup process ends.

[0055] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0056] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydrogen fuel cell vehicle startup control method, characterized in that: Control methods include: S1: Power on and wake up the vehicle control unit (VCU) and perform self-test; S2: Turn on the ignition switch and check whether the high voltage conditions are met. If the high voltage conditions are not met, the instrument will display a fault message. If the high voltage conditions are met, the instrument will display a high voltage success message. S3: Press the hybrid switch to enter the hydrogen fuel cell start mode, and if not pressed, it enters the pure electric driving mode; S4: Determine whether the power battery cell temperature is greater than T0. If it is greater than or equal to T0, the hydrogen fuel cell enters the normal temperature start mode; if it is less than T0, the hydrogen fuel cell enters the low temperature start mode; T0 is a preset temperature value; The normal temperature start-up mode of the hydrogen fuel cell includes the following steps: S41: Entering the fuel cell normal temperature starting mode; S42: Collect the power battery discharge power P 放 , Hydrogen fuel cell starting power P 起 Plus vehicle accessories power P 附 And judge, if P 放 <P 起 +P 附 , then the instrument will issue a prompt to charge first and then start the fuel cell. If P 放 >P 起 +P 附 , then proceed to step S43; S43: Check whether the power battery's SOC is higher than 70%. If higher than 70%, operate in pure electric mode to reduce the SOC. After the SOC is lower than 70%, the fuel cell system is allowed to start. S44: After receiving the start command, the hydrogen fuel cell control unit FCU performs a system self-check. If there is no fault, the start process is executed and the system enters the idle operation state; The hydrogen fuel cell low temperature start mode includes the following steps: S45: Collect the power battery discharge power P 放 , Hydrogen fuel cell starting power P 起 Plus vehicle accessories power P 附 And judge, if P 放 <P 起 +P 附 , then the instrument will issue a prompt to charge first and then start the fuel cell. If P 放 >P 起 +P 附 , then proceed to step S46; S46: The VCU forcibly shuts down accessories such as the heating system APTC and the battery heating device WPTC to ensure that the power battery has sufficient discharge power for the fuel cell to start; S47: Check whether the power battery's SOC is higher than 80%. If higher than 80%, operate in pure electric mode to reduce the SOC. The fuel cell system is then allowed to start after the SOC drops below 80%. S48: After receiving the start command, the hydrogen fuel cell control unit FCU performs a system self-check and executes the start process if there is no fault. The hydrogen fuel cell control unit FCU independently completes the data collection, working status control and fault diagnosis of the hydrogen fuel cell. Its start, stop and power request are carried out according to the instructions of the vehicle control unit VCU; After the hydrogen fuel cell control unit FCU is successfully started, the vehicle control unit VCU will set the power battery to allow charging power P 充 and fuel cell output power P 出 For comparison, if P 充 Less than P 出 , forcefully open all accessories of the vehicle to prevent the fuel cell from outputting too much power to charge the power battery and reporting an overcharge fault.

2. The hydrogen fuel cell vehicle startup control method according to claim 1, characterized in that: The vehicle control unit VCU communicates with the power battery control system BMS, hydrogen fuel cell control unit FCU, instrument IC, power battery heating device WPTC and heating system APTC through the vehicle CAN bus. The current physical quantities and working status collected by each system are sent to the vehicle CAN bus through messages for use by related systems.

3. The hydrogen fuel cell vehicle startup control method according to claim 1, characterized in that: The vehicle control unit VCU collects the power battery's allowable charging power, allowable discharging power, cell temperature, charge capacity ratio SOC, fault information, fuel cell system starting power consumption, discharge power, working status, fault information, power mode switch status, and the working status of each accessory, and controls the working status of each component through energy balance calculation.

4. The hydrogen fuel cell vehicle startup control method according to claim 3, characterized in that: The energy balance calculation formula is: ,in, Input energy into the fuel, For electrical output energy, is the heat output energy, For energy loss.

5. The hydrogen fuel cell vehicle startup control method according to claim 1, characterized in that: The power battery control system BMS collects and sends out voltage, current, and allowable discharge power P 放 , allowable charging power P 充 , battery cell temperature T 芯 , charge capacity SOC and the status and fault information of each relay, and execute each instruction issued by the vehicle control unit VCU according to the set process.

6. The hydrogen fuel cell vehicle startup control method according to claim 1, characterized in that: The starting control methods of hydrogen fuel cell vehicles are divided into normal temperature starting mode and low temperature starting mode. Before starting the hydrogen fuel cell, the entire vehicle must first perform the high-voltage process.

7. The hydrogen fuel cell vehicle startup control method according to claim 1, characterized in that: When the power battery cell temperature is low and the SOC is low and the discharge power does not meet the hydrogen fuel cell startup requirements, the vehicle control unit VCU will send a prompt to remind the driver to charge in pure electric mode before starting the hydrogen fuel cell. When the power battery SOC is too high, the VCU will prohibit the fuel cell from starting.

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