Fuel cell automobile low-temperature starting method and automobile

Abstract

The invention discloses a fuel cell automobile low-temperature starting method and an automobile The method comprises the steps that a TBOX obtains a remote low-temperature cold starting instruction sent by a user in real time and collects the ignition state in real time; and starting a low-temperature heating strategy: collecting the temperature of the fuel cell, the environment temperature and the temperature of the lithium battery, and controlling a PTC heater to perform heating control on the fuel cell and the lithium battery based on the temperature. The low-temperature heating starting control of the hydrogen fuel cell is realized for the vehicle integrated with the auxiliary lithium battery in the hydrogen fuel cell vehicle, the waiting time is reduced, the use of the fuel cell vehicle at low temperature of a user is met, and the user experience is improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell winter heating start control, and particularly to a fuel cell vehicle low-temperature start method and vehicle. Background Technology

[0002] Hydrogen fuel cells are a highly efficient new energy power generation system that has emerged in recent years. They generate electricity through the reaction of hydrogen and oxygen, offering advantages such as high efficiency and zero emissions. With the increasing popularity of fuel cells in recent years, the start-up time of fuel cell vehicles has become a major concern, especially their low-temperature start-up performance. Currently, many companies still use PTC (Potentially Transformer Cipher Cell) heating for low-temperature heating. PTC heating offers advantages such as stable heating, low control difficulty, and minimal impact on stack performance. However, PTC heating at low temperatures is relatively slow, and the heating time is also longer. Currently, fuel cell vehicles are still in the popularization stage and are often used in conjunction with a large-capacity lithium battery. If the fuel cell cannot start or starts slowly at low temperatures, the driver can use the lithium battery to drive alone. Therefore, the start-up performance of fuel cells is not currently a major concern. However, the ultimate trend for fuel cell vehicles will undoubtedly be the use of smaller-capacity batteries, with the fuel cell as the primary component and the lithium battery as a secondary component. In this scenario, the long start-up time of fuel cell systems using PTC heating in low-temperature environments will become a significant issue, leading to a rapid drop in State of Charge (SOC) and limited output power.

[0003] Currently, fuel cell vehicles have two starting methods in low-temperature environments: The first method involves the driver directly starting the vehicle and activating the fuel cell system. In this case, the lithium battery discharges to heat the fuel cell's PTC (Power Transmission Control Center). The fuel cell does not generate electricity at this stage. During this process, the lithium battery not only needs to power the vehicle but also supply power to the fuel cell during startup. This method is feasible for hybrid vehicles with large-capacity lithium batteries and fuel cells. However, it presents problems for fuel cell vehicles with low-capacity lithium batteries and short driving ranges. In this method, the lithium battery primarily functions as an auxiliary power source and cannot meet the vehicle's range requirements. Often, the lithium battery depletes before the fuel cell heating process is complete, leaving the vehicle stranded and unable to move.

[0004] The second starting method: In low-temperature environments, the driver chooses to wait for the fuel cell to heat up before starting the vehicle. Although this starting method can avoid the situation of power depletion under low SOC, the driver needs to wait for the fuel cell to start before starting the vehicle. This process takes a long time, which is not acceptable for commercial vehicle transportation that emphasizes efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-temperature start-up method and vehicle for fuel cell vehicles. This invention enables low-temperature heating start-up control of hydrogen fuel cells in vehicles with integrated auxiliary lithium batteries, reducing waiting time, meeting the user's needs for using fuel cell vehicles in low-temperature conditions, and improving the user experience.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a low-temperature start-up method for a fuel cell vehicle, comprising:

[0007] TBOX acquires remote low-temperature cold start commands sent by users in real time and collects ignition status in real time. When the vehicle is not ignited, it starts a low-temperature heating strategy: it collects fuel cell temperature, ambient temperature, and lithium battery temperature and controls the PTC heater to heat the fuel cell and lithium battery based on this.

[0008] The TBOX is connected to the vehicle's constant power supply. When the vehicle is powered down, the TBOX is in a dormant state. When it receives a command from the user via mobile phone, the TBOX is immediately awakened. The TBOX performs a security verification of the user's command. After the verification is successful, the TBOX sends a message to wake up the vehicle's body control module (BCM) and forwards the fuel cell start command to the BCM. When the BCM receives the fuel cell start command, it issues a command to start and complete the low-voltage power distribution of the vehicle. After powering on in the ON position, it wakes up the vehicle control unit (VCU) and forwards the system start command to the VCU. After receiving the command, the VCU initiates the vehicle power-on process to complete the high-voltage power supply of the vehicle, and the entire vehicle enters the Ready state. It then issues a fuel cell start command. The BCM collects ambient temperature, fuel cell coolant temperature, and lithium battery temperature, and then uses the collected ambient temperature, fuel cell coolant temperature, and lithium battery temperature to control the heating of the lithium battery and fuel cell.

[0009] When controlling the heating of hydrogen fuel cells and lithium batteries, the BCM feeds back the heating information to the TBOX via the CAN network, and then the TBOX feeds it back to the user's APP client; the heating information includes the heating status of the lithium battery and fuel cell, and the temperature of the lithium battery and fuel cell.

[0010] Heating control of lithium batteries and fuel cells based on ambient temperature, fuel cell coolant, and lithium battery temperature collected by the BCM includes:

[0011] Condition 1: When the ambient temperature is less than the first temperature threshold, the fuel cell coolant temperature is less than the second temperature threshold, and the lithium battery temperature is less than the third temperature threshold, then control the fuel cell heating to start and the lithium battery heating to start.

[0012] Condition 2: When the ambient temperature is less than the first temperature threshold, the fuel cell coolant temperature is less than the second temperature threshold, and the lithium battery temperature is greater than the third temperature threshold, then control the fuel cell heating to turn on and the lithium battery heating to turn off.

[0013] If neither condition 1 nor condition 2 is met, it is determined that the fuel cell does not require a cold start, and the PTC heater will not work at this time.

[0014] If neither condition 1 nor condition 2 is met, the SOC value of the lithium battery at this time is collected, and the fuel cell is started to charge the lithium battery based on the SOC value of the lithium battery. If the SOC value of the lithium battery is lower than the set SOC threshold, the fuel cell is started to charge the lithium battery. After the lithium battery is charged to the SOC threshold, the charging stops, and then the vehicle power-off process is entered, and the charging information is fed back to the user's app client through the TBOX.

[0015] When the fuel cell is started to recharge the lithium battery, the charging power of the fuel cell is controlled according to the SOC value of the lithium battery, and the lower the SOC value, the greater the power of the fuel cell during recharging.

[0016] When the fuel cell heating control is activated, after the fuel cell controller FCCU receives the start command, the lithium battery continuously supplies power to the fuel cell system. The fuel cell first enters the cold start mode, turns on the water pump, turns off the thermostat, enables the PTC heater, and then returns to the heating state. The heating completion status is fed back to the user's APP client through the TBOX.

[0017] After the low-temperature heating strategy is activated, if the user's driving needs are detected, i.e. the vehicle gear is switched to D or R, the lithium battery will provide driving power to the power system. Based on the lithium battery temperature and the remaining SOC, the driving range is estimated and a reminder message is sent to the user through the vehicle system or the user's mobile app client, indicating that the fuel cell is not activated under the current low temperature conditions and the vehicle is only powered by the lithium battery, and informing the user of the estimated driving range.

[0018] If the user shifts the gear to D or R when the fuel cell is not started, the time T1 required for the fuel cell to heat up to the point where it can start working is estimated based on the fuel cell temperature and the working status of the PTC heater. The time T2 required for the vehicle to be driven by the lithium battery alone until the lithium battery is depleted is also estimated. Based on the calculated times T1 and T2, it is determined whether the vehicle will experience a power depletion before the fuel cell starts working, and the predicted power depletion status information is sent to the vehicle system or the user's mobile app to notify the user.

[0019] A fuel cell vehicle, wherein the fuel cell vehicle employs the aforementioned low-temperature start-up control method for low-temperature start-up control.

[0020] The advantages of this invention are: it enables low-temperature heating and start-up control of hydrogen fuel cells in vehicles with integrated auxiliary lithium batteries, reducing waiting time, meeting user needs for fuel cell vehicles in low-temperature conditions, and improving user experience. Without altering the fuel cell system structure, a mobile app and the vehicle's built-in TBOX, combined with a suitable remote start strategy, are used to start the vehicle's heating system. This ensures rapid heating of the lithium battery while driving the fuel cell PTC, keeping both the lithium battery and the fuel cell within their optimal operating temperature range. This meets the driver's need for rapid, high-power departure from the vehicle and minimizes the risks of battery depletion and driver waiting. Attached Figure Description

[0021] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings:

[0022] Figure 1 This describes the hardware connection relationships of the fuel cell vehicle involved in the startup method of this invention;

[0023] Figure 2 This is a flowchart of the startup control method of the present invention. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0025] This solution addresses the challenges of fuel cell vehicles, which utilize both fuel cells and lithium batteries. The fuel cell serves as the primary power source, while the lithium battery acts as an auxiliary power source. However, the lithium battery's capacity is relatively small and insufficient to support long-distance driving. Based on this fuel cell-dominant, lithium battery-assisted power system, a low-temperature start-up control solution is implemented to reduce waiting time and improve user experience. Specific solutions include:

[0026] like Figure 1 , 2As shown, a low-temperature start-up method for a fuel cell vehicle includes: when the user is not in the vehicle, sending a remote control command via a mobile app client; when the user needs to use the fuel cell vehicle in the future, the user can estimate whether the fuel cell needs to be started at a low temperature based on the current temperature; based on the judgment result, the user actively sends a low-temperature start-up control command to the on-board TBOX of the fuel cell vehicle via the mobile app client; the on-board TBOX receives the remote low-temperature cold start command sent by the user in real time and collects the ignition status in real time; since the user remotely controls the vehicle, the vehicle is not in the ignition state at this time, and the vehicle does not need to drive, only to execute the heating strategy, so at this time the low-temperature heating strategy is activated, and the fuel cell and lithium battery are heated and controlled under the low-temperature heating strategy. The heating control strategy includes: collecting the fuel cell temperature, ambient temperature, and lithium battery temperature, and controlling the PTC heater to heat the fuel cell and lithium battery based on these.

[0027] The TBOX is connected to the vehicle's constant power supply. When the vehicle is powered down, the TBOX is in a dormant state. When it receives a command from the user via mobile phone, the TBOX is immediately awakened. The TBOX performs a security verification of the user's command. After the verification is successful, the TBOX sends a message to wake up the vehicle's body control module (BCM) and forwards the fuel cell start command to the BCM. When the BCM receives the fuel cell start command, it issues a command to start and complete the low-voltage power distribution of the vehicle. After powering on in the ON position, it wakes up the vehicle control unit (VCU) and forwards the system start command to the VCU. After receiving the command, the VCU initiates the vehicle power-on process to complete the high-voltage power supply of the vehicle, and the entire vehicle enters the Ready state. It then issues a fuel cell start command. The BCM collects ambient temperature, fuel cell coolant temperature, and lithium battery temperature, and then uses the collected ambient temperature, fuel cell coolant temperature, and lithium battery temperature to control the heating of the lithium battery and fuel cell.

[0028] When controlling the heating of hydrogen fuel cells and lithium batteries, the BCM feeds back the heating information to the TBOX via the CAN network, and then the TBOX feeds it back to the user's APP client. The heating information includes the heating status and temperature of the lithium battery and fuel cell, which is fully understood by the user so that the user can get into the vehicle and drive as needed.

[0029] Heating control of lithium batteries and fuel cells based on ambient temperature, fuel cell coolant, and lithium battery temperature collected by the BCM includes:

[0030] Condition 1: When the ambient temperature is less than the first temperature threshold, the fuel cell coolant temperature is less than the second temperature threshold, and the lithium battery temperature is less than the third temperature threshold;

[0031] If all conditions in 1 are met, then control the fuel cell heating to turn on and the lithium battery heating to turn off.

[0032] Condition 2: When the ambient temperature is less than the first temperature threshold, the fuel cell coolant temperature is less than the second temperature threshold, and the lithium battery temperature is greater than the third temperature threshold;

[0033] If all conditions in condition 2 are met, then control the fuel cell heating to turn on and the lithium battery heating to turn off;

[0034] If neither condition 1 nor 2 is met, the fuel cell is determined not to require a cold start, and the PTC heater does not operate. When neither condition 1 nor 2 is met, the SOC value of the lithium battery is collected, and the fuel cell is activated to charge the lithium battery based on the SOC value. If the lithium battery SOC value is lower than a set SOC threshold, the fuel cell is activated to recharge the lithium battery. Recharging stops once the SOC threshold is reached, and the vehicle enters the power-off process, with the recharging information being fed back to the user's app via the TBOX. When heating control is not required, the fuel cell can be started at any time. To ensure the lithium battery SOC remains high, the SOC value needs to be monitored. If the lithium battery SOC is lower than a set threshold, the fuel cell is activated to recharge the lithium battery, ensuring the lithium battery's charge remains high for future use.

[0035] In this scheme, when the fuel cell is activated to recharge the lithium battery, the charging power of the fuel cell is controlled according to the state of charge (SOC) value of the lithium battery; the lower the SOC value, the greater the charging power of the fuel cell. When the vehicle starts and charging begins:

[0036] If SOC > 90%, the fuel cell will not start, and the vehicle will proceed with the power-off process.

[0037] If SOC <= 85%, the fuel cell charges the lithium battery at 20% of its rated power.

[0038] If SOC <= 75%, the fuel cell charges the lithium battery at 30% of its rated power.

[0039] If SOC <= 65%, the fuel cell charges the lithium battery at 50% of its rated power.

[0040] In this solution, if it is determined that fuel cell heating control needs to be activated, the fuel cell controller (FCCU) receives a start command and the lithium battery continuously supplies power to the fuel cell system. The fuel cell first enters cold start mode, turns on the water pump, turns off the thermostat, enables the PTC heater, and then returns to heating mode. The heating completion status is fed back to the user's APP client via the TBOX. After the PCCU controls the PTC heater to work, it collects heating status and temperature data in real time and feeds it back to the user. Based on this, the user can monitor the fuel cell status and obtain status information. The user can adjust the vehicle's usage status and needs at any time according to the information obtained.

[0041] After activating the low-temperature heating strategy, if a user's driving demand is detected (i.e., the vehicle shifts to D or R gear), a short-duration driving mode is entered. In this mode, the lithium battery provides driving power to the power system and simultaneously supplies power for fuel cell heating. Since the lithium battery's energy capacity is relatively low, its range is limited. Therefore, a reminder is needed to the user. This solution estimates the driving range based on the lithium battery temperature and remaining SOC and sends a reminder message to the user via the vehicle's infotainment system or the user's mobile app, indicating that the fuel cell is not activated in the current low-temperature conditions and the vehicle is powered solely by the lithium battery, along with the estimated driving range. This allows the user to know the status of the vehicle's power system and the estimated driving range, enabling them to decide whether to continue driving and providing basic reference data for the user's fuel cell usage. The estimated driving range data is obtained by looking up a pre-calibrated map table based on the lithium battery temperature and SOC data.

[0042] Since the vehicle starts operating under a low-temperature heating strategy, if the time required for the fuel cell to heat up to a point where it can start is much shorter than the time required for the lithium battery to provide range until it is depleted, the user can start the vehicle without affecting direct use. Therefore, it is necessary to calculate and predict this state and provide a reminder to the user. In this solution, when the fuel cell is not running, if the user shifts to D or R, the time T1 required for the fuel cell to heat up to a point where it can start operating is estimated based on the fuel cell temperature and the PTC heater's operating status. The time T2 required for the vehicle to run solely powered by the lithium battery until the lithium battery is depleted is also estimated. Based on the calculated times T1 and T2, it is determined whether the vehicle will experience a power depletion before the fuel cell starts operating, and the predicted power depletion status information is sent to the vehicle's infotainment system or the user's mobile app to notify the user. If T1 is less than T2, the judgment result is that the user's use of the vehicle at this time will not cause the lithium battery to run out of power, and the user can use it with confidence. Otherwise, the judgment result is that the user's use of the vehicle will cause the lithium battery to run out of power, and the judgment result will be sent to the user's mobile app or vehicle system to notify the user, so that the user can adjust the use of the vehicle according to the actual situation. This avoids the defect that users need to use the vehicle in an emergency but cannot know whether the vehicle will run out of power and break down after use, which leads to the user not having a complete grasp of vehicle information and affecting the user experience. Time T1 is the time required for the fuel cell temperature to rise from the current temperature to the allowable start-up temperature, calculated based on the fuel cell temperature rise rate. Time T2 is the time required to provide power when the current battery is depleted and the battery reaches the depletion state of charge (SOC) after the user uses the vehicle per unit time, based on the current battery level and the power that can be provided when the battery is depleted, calculated based on the current battery level and the power that can be provided when the battery is depleted, under the unit battery power consumption.

[0043] If the user does not activate the low-temperature heating strategy remotely (i.e., the user directly starts the vehicle and shifts to D or R gear), the ambient temperature, fuel cell coolant temperature, and lithium battery temperature are collected to determine whether the lithium battery and fuel cell need heating. If the ambient temperature is below 0 degrees Celsius and the lithium battery temperature is below zero degrees Celsius, the lithium battery is determined to need heating; if the ambient temperature is below 0 degrees Celsius and the fuel cell coolant temperature is below 0 degrees Celsius, the fuel cell is determined to need heating. Then, the lithium battery supplies power to the PTC heater, activating the PTC heater to heat the fuel cell and / or lithium battery. Simultaneously, a short-duration driving mode is entered, where the lithium battery provides driving power to the power system and also supplies power to the fuel cell heater. Since the lithium battery has a relatively low energy capacity, its range is limited. Therefore, a reminder is needed for the user. This solution estimates the driving range based on the lithium battery temperature and remaining SOC and sends a reminder message to the user via the vehicle's infotainment system or the user's mobile app, indicating that the fuel cell is not activated in the current low-temperature conditions and the vehicle is powered solely by the lithium battery, along with the estimated driving range. This allows users to see the current state of the vehicle's powertrain and the estimated driving range, enabling them to decide whether to continue driving based on the current status. It also provides fundamental reference data for users regarding the type of fuel cell. The estimated driving range is obtained by looking up pre-calibrated maps using lithium battery temperature and SOC data.

[0044] This solution also provides a fuel cell vehicle that employs the low-temperature start-up control method described in the above embodiments for low-temperature start-up control. Due to the adoption of the aforementioned low-temperature start-up control method, this fuel cell vehicle possesses all the technical advantages and characteristics of the low-temperature start-up control method.

[0045] This solution, without altering the fuel cell system structure, utilizes a mobile app and the vehicle's built-in battery box (TBOX) in conjunction with a suitable remote start strategy to activate the vehicle's heating system. This ensures rapid heating of the lithium battery while simultaneously driving the fuel cell's power supply (PTC), keeping both the lithium battery and the fuel cell within their optimal operating temperature range. This meets the driver's need for quick, high-powered departure from the vehicle, minimizing the risks of battery depletion and driver waiting. Furthermore, using a mobile app and the vehicle's TBOX in conjunction with a suitable remote start strategy to activate the vehicle's heating system ensures rapid heating of the lithium battery while simultaneously driving the fuel cell's PTC, keeping both the lithium battery and the fuel cell within their optimal operating temperature range. This allows the driver to immediately start and drive away upon arrival, alleviating driver anxiety, reducing the risk of battery depletion, and improving the driving experience.

[0046] This solution relates to the field of fuel cell vehicles. It mainly uses remote control to control the fuel cell heating system in real time, thereby achieving rapid start-up of fuel cell vehicles at low temperatures, alleviating driver anxiety while waiting and reducing the risk of battery depletion.

[0047] A specific use case is as follows: On a cold winter day, a driver has just gotten up and, after preparing, goes to his car to start the fuel cell vehicle. The following might happen:

[0048] 1. The driver immediately starts the vehicle and drives away: Because the discharge performance of lithium batteries is also very poor at low temperatures, the external discharge current is limited. While the vehicle is running at limited power, it also needs to continue to supply power to the fuel cell heating PTC. The SOC drops rapidly, and the risk of the vehicle running out of power continues to increase.

[0049] 2. The driver waits for the vehicle to start before driving away: Although the lithium battery's low-temperature charging and discharging capabilities are weak, it doesn't need to power the entire vehicle at this time, so the PTC heating requirement can be met. After about 10 minutes, the driver drives the vehicle away, and the fuel cell starts working normally and begins charging the lithium battery. While this method reduces the risk of the vehicle breaking down, it increases the driver's anxiety while waiting.

[0050] The vehicle heating system in this solution mainly consists of two parts:

[0051] 1. Lithium battery heating system: The battery management system (BMS) adjusts and controls the heating based on the ambient temperature. When the vehicle is started in a low-temperature environment, the BMS will activate the battery heating system to quickly raise the temperature and increase the maximum discharge power.

[0052] Second: Fuel cell heating system. At low temperatures, the fuel cell controller (FCU) heats the coolant to a suitable temperature based on the current coolant temperature. After heating is completed, the fuel cell starts working according to the normal startup process.

[0053] This solution includes sensors to detect whether the seats are occupied in the fuel cell vehicle.

[0054] This solution involves the vehicle network architecture, which includes three CAN channels. The first CAN channel, CAN1, is the VCU calibration and flashing CAN; the second CAN channel, CAN2, is the VCU power CAN, which generally includes information related to the transmission and motor; and the third CAN channel, CAN3, is the communication CAN between other subsystems and the VCU.

[0055] The fuel cell system includes four CAN channels: CAN1 for calibration and programming, CAN2 for CVM-related information, CAN3 for VCU communication (primarily responsible for communicating with the VCU, receiving control commands, and relaying relevant information back to the VCU), and CAN4 for internal communication with subsystems. The overall network topology is as follows: Figure 1 :

[0056] BMS stands for Battery Management System, FCCU for Fuel Cell Controller, BCM for Body Controller, and TBOX for Vehicle Information and Positioning Transmission System, which users can communicate with via a mobile app.

[0057] In this solution, the TBOX communication CAN network is located on CAN3, which connects the VCU and FCCU. This network also houses related controllers such as the BCM (Body Management System) and the BMS (Battery Management System), with all components communicating via the CAN network. Other sub-networks are internal networks within the VCU and FCU, which will not be discussed in detail here.

[0058] Therefore, the proposed solution in this embodiment is based on the above network architecture, and at least TBOX, BMS, VCU, FCU and other control systems need to be deployed on CAN3.

[0059] The specific implementation steps are as follows:

[0060] 1. When the driver determines that the ambient temperature is too low and the vehicle needs a cold start, they can choose to start the vehicle remotely via the APP. Specifically, the driver needs to open the mobile APP beforehand. This APP can communicate and control the vehicle's TBOX (Total Vehicle Infotainment System). The driver opens the APP and clicks the vehicle cold start command, sending a start command to the TBOX via their mobile phone to start the system in advance.

[0061] Second: The TBOX is connected to a constant 24V power supply in the vehicle. When the vehicle is powered off, the TBOX is in a sleep state. When it receives a command from the mobile phone, the TBOX is immediately woken up. The TBOX performs a security verification on the APP command. If the verification is successful, the TBOX sends a specific message to wake up the vehicle body controller (BCM) and forwards the fuel cell start command. If the verification fails, no further actions are performed.

[0062] 3. When the BCM receives the fuel cell start command, it issues a command to start and complete the low-voltage power distribution of the whole vehicle. After the vehicle is powered on in the ON position, it wakes up the VCU and forwards the system start command to the VCU. After receiving the command, the VCU starts the whole vehicle power-on process to complete the high-voltage power supply of the whole vehicle. The whole vehicle enters the Ready state and issues the fuel cell start command.

[0063] 4. Simultaneously, the BCM collects ambient temperature, fuel cell coolant temperature, and lithium battery temperature. The heating logic is executed according to the table below. The BCM feeds back the heating information to the TBOX via the CAN network, and then the TBOX feeds it back to the APP client. Specific feedback content:

[0064] Option 1: The gas-fired battery activates the heating function, while the lithium battery activates the heating function.

[0065] Option 2: Gas-fired electric heating.

[0066]

[0067] 5. Heating of fuel cells and lithium batteries should be carried out according to the strategy in the table above.

[0068] When the ambient temperature, fuel cell coolant temperature, and lithium battery temperature are all below 0 degrees Celsius, the FCU controls the fuel cell power system to activate the fuel cell PTC heater, and the BMS controls the lithium battery to heat up.

[0069] When the ambient temperature and fuel cell coolant temperature are below 0 degrees Celsius, and the lithium battery temperature is above 0 degrees Celsius, the FCU controls the fuel cell system to activate the fuel cell PTC heater.

[0070] Heating methods for gas-fired electric systems:

[0071] After receiving the start command, the fuel cell controller (FCCU) continuously supplies power to the fuel cell system via the lithium battery. The fuel cell first enters cold start mode, turning on the water pump, turning off the thermostat, enabling PTC heating, and then returning to heating mode. Heating completion status is reported to the APP client via the TBOX, allowing the driver to proceed with driving the vehicle. Once heating is complete, power can be output externally; the power output can be listed in step seven.

[0072] Lithium battery heating method: The lithium battery heating is controlled by the BMS battery management system according to the actual temperature of the lithium battery.

[0073] 7. When it is determined that the vehicle does not belong to either of the above two schemes, a cold start is not required. Instead, the fuel cell system needs to be started to charge the lithium battery based on the vehicle's real-time SOC. The efficiency of the fuel cell gradually decreases as the output power increases. E To achieve the system's maximum output power, considering fuel efficiency and SOC (State of Charge), charging should follow this strategy. The specific logic is as follows:

[0074] SOC Power Request SOC>90% 0 SOC<=85% <![CDATA[20%*P E ]]> SOC<=75% <![CDATA[30%*P E ]]> SOC<=65% <![CDATA[50%*P E ]]>

[0075] When the vehicle starts charging

[0076] If SOC > 90%, the fuel cell will not start, and the vehicle will proceed with the power-off process.

[0077] If SOC <= 85%, the fuel cell charges the lithium battery at 20% of its rated power.

[0078] If SOC <= 75%, the fuel cell charges the lithium battery at 30% of its rated power.

[0079] If SOC <= 65%, the fuel cell charges the lithium battery at 50% of its rated power.

[0080] 8. When a seat occupancy signal and braking signal are detected during remote start-up, the remote control mode exits and switches directly to normal mode. The vehicle will then proceed with heating, charging, or driving according to the pre-defined strategy and driver's instructions.

[0081] 9. During the remote start process, when the lithium battery SOC rises to 90%, if no occupant signal is detected, the fuel cell will execute a shutdown procedure. Subsequently, the vehicle will begin its normal power-off process, and the TBOX will send a message to the APP client indicating that the vehicle is fully charged. The feedback message will be: "Fully charged, remote start automatically shut off."

[0082] This solution, without altering the fuel cell system structure, utilizes a mobile app and the vehicle's built-in TBOX, along with a suitable remote start strategy, to activate the vehicle's heating system. This ensures rapid heating of the lithium battery while simultaneously driving the fuel cell PTC, keeping both the lithium battery and the fuel cell within their optimal operating temperature range. This meets the driver's need for rapid, high-power departure from the vehicle and minimizes the risks of battery depletion and driver waiting. Furthermore, it provides predictive information on vehicle operation when powered solely by the lithium battery, allowing users to control the vehicle based on this information.

[0083] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A method for low temperature start-up of a fuel cell vehicle, characterized by: The application relates to a hydrogen fuel cell vehicle low-temperature cold start method and system. The TBOX is connected with a vehicle in a constant power mode, and in the case that the whole vehicle is powered off, the TBOX is in a sleep state; when a user instruction is received, the TBOX is woken up immediately, the TBOX carries out safety verification on the user instruction, and after the verification is passed, the TBOX sends a message to wake up a body controller BCM and forwards a fuel cell start instruction to the BCM; after the BCM receives the fuel cell start instruction, the BCM issues an instruction to start and complete low-voltage power distribution of the whole vehicle, wakes up a vehicle control unit VCU in an on mode, and forwards a system start instruction to the VCU; after the VCU receives the instruction, the whole vehicle is powered on, high-voltage power supply of the whole vehicle is completed, and the whole vehicle enters a ready state and issues a fuel start instruction; the BCM collects environment temperature, fuel cell coolant temperature and lithium battery temperature, and then controls heating of the lithium battery and the fuel cell based on the collected environment temperature, fuel cell coolant temperature and lithium battery temperature.

2. A method for low temperature starting of a fuel cell vehicle as defined in claim 1, characterized by: When the lithium battery and the fuel cell are controlled to be heated, the BCM feeds back heating information to the TBOX through a CAN network, and the TBOX feeds back the heating information to an APP client of the user; wherein the heating information comprises heating states of the lithium battery and the fuel cell and temperatures of the lithium battery and the fuel cell.

3. A method of low temperature starting a fuel cell vehicle as claimed in claim 1 or 2, characterised in that: The heating control of the lithium battery and the fuel cell based on the collected environment temperature, fuel cell coolant temperature and lithium battery temperature comprises:

4. A method of low temperature starting a fuel cell vehicle as claimed in claim 1 or 2, characterised in that: Condition 1: when the environment temperature is less than a first temperature threshold, the fuel cell coolant temperature is less than a second temperature threshold, and the lithium battery temperature is less than a third temperature threshold, the fuel cell heating is controlled to be started and the lithium battery heating is controlled to be started; Condition 2: when the environment temperature is less than the first temperature threshold, the fuel cell coolant temperature is less than the second temperature threshold, and the lithium battery temperature is greater than the third temperature threshold, the fuel cell heating is controlled to be started and the lithium battery heating is controlled to be stopped; When neither the condition 1 nor the condition 2 is satisfied, it is judged that the fuel cell does not need to be cold started, and the PTC heater does not work. When neither the condition 1 nor the condition 2 is satisfied, a lithium battery SOC value at the moment is collected, and whether the fuel cell is started to charge the lithium battery is judged based on the lithium battery SOC value; if the lithium battery SOC value is lower than a set SOC threshold, the fuel cell is started to charge the lithium battery, the lithium battery charging is stopped after the lithium battery charging reaches the SOC threshold, and then a vehicle power-off process is entered and charging information is fed back to the APP client of the user through the TBOX.

5. A method of low temperature starting a fuel cell vehicle as defined in claim 4, characterized by: When the fuel cell is started to charge the lithium battery, the charging power of the fuel cell is controlled according to the SOC value of the lithium battery, and the lower the SOC value, the greater the power of the fuel cell charging.

6. A method of low temperature starting a fuel cell vehicle as defined in claim 5, characterized by: ​ 7. A method of starting a fuel cell vehicle at low temperature according to any one of claims 1 to 6, characterized by: When the fuel cell heating control is started, the fuel cell controller FCCU receives a start instruction, the lithium battery continuously supplies power to the fuel cell system, the fuel cell first enters a cold start mode, the water pump is started, the thermostat is closed, the PTC heater is enabled to work, and the heating state is returned. The heating completion state is fed back to the user APP client through the TBOX.

8. A method of starting a fuel cell vehicle at low temperature according to any one of claims 1 to 6, characterized by: After starting the low-temperature heating strategy, if the user's driving demand is detected, that is, the vehicle gear is switched to D or R, the lithium battery provides driving power for the power system, and the estimated driving range is estimated based on the lithium battery temperature and the remaining SOC. A reminder message is sent to the user through the car system or the user's mobile phone app client, prompting that the fuel cell has not started under the current low-temperature condition and only lithium battery power is used for driving, and informing the user of the estimated driving range.

9. A method of low temperature starting a fuel cell vehicle as defined in claim 8, characterized by: If the user switches the gear to D or R under the condition that the fuel cell has not started, at this time, the time T1 required for the fuel cell to heat up to the allowed start working state is estimated based on the fuel cell temperature and the working state of the PTC heater, and the time T2 for the vehicle to drive to the lithium battery feeding corresponding state is estimated based on the lithium battery power alone. Based on the calculated time T1 and T2, it is judged whether the vehicle will be fed before the fuel cell starts working, and the predicted feeding state information is sent to the user through the car system or the user's mobile phone app client to inform the user.

10. A fuel cell vehicle characterized by comprising: The fuel cell vehicle adopts the low-temperature start control method according to any one of claims 1-9 to perform low-temperature start control.

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