A fuel cell vehicle low-temperature environment thermal management method, device and vehicle

Abstract

This invention belongs to the field of vehicle control technology and discloses a method, device, and vehicle for low-temperature environmental thermal management of fuel cell vehicles. The method acquires the ambient temperature (first temperature sensor) and the state of charge (SOC) of the vehicle's power battery; based on the ambient temperature (first temperature sensor) and the power battery SOC, it controls the operating strategies of the PTC1 heater, PTC2 heater, PTC3 heater, and fuel cell to fully utilize the waste heat generated during fuel cell operation. This invention improves the environmental compatibility and service life of the fuel cell, achieves overall vehicle energy balance, and extends the service life of the fuel cell and the vehicle's driving range.

Description

Technical Field

[0001] This invention belongs to the field of vehicle control technology, and in particular relates to a method, device and vehicle for thermal management in low-temperature environments of fuel cell vehicles. Background Technology

[0002] Fuel cell vehicles are shifting from pure fuel cell electric vehicles to fuel cell plug-in hybrid and fuel cell range-extended hybrid configurations. However, most thermal management solutions for fuel cell vehicles are geared towards traditional full-power configuration vehicles, failing to consider the low charging efficiency of power batteries and the reduction in driving range caused by low temperatures in winter, and failing to address the issue of battery damage in low-temperature environments. Summary of the Invention

[0003] To overcome the problems existing in related technologies, the present invention discloses an embodiment of a method, device and vehicle for thermal management in low-temperature environments of fuel cell vehicles.

[0004] The technical solution is as follows: A method for thermal management of fuel cell vehicles in low-temperature environments, the method comprising:

[0005] S1, acquire the ambient temperature monitored by the first temperature sensor, the vehicle's power battery SOC, and the cabin's heating temperature requirements.

[0006] S2 determines the fuel cell start-up requirements based on ambient temperature and the SOC of the power battery. Based on these requirements, it controls the PTC1 heater and the fuel cell system's operating strategy, selecting cold start, thermal management, and energy management strategies to achieve a non-destructive, low-temperature cold start while utilizing the waste heat generated during fuel cell operation. Based on the cabin heating requirements and the utilization of fuel cell waste heat, it determines the operating control strategy for the second PCT heater, using waste heat from the fuel cell system to heat the cabin and reduce electric heating energy consumption. Based on the power battery's thermal management requirements and the utilization of fuel cell waste heat, it controls the operating strategy of the PTC3 heater to support the power battery in quickly reaching the target operating temperature, improving power battery discharge efficiency and reducing electric heating energy consumption.

[0007] In step S1, the vehicle includes a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system (second temperature sensor) are connected through a first liquid-liquid heat exchanger.

[0008] The cockpit thermal management system (second temperature sensor) and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system (second temperature sensor) includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater.

[0009] In step S2, the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell are controlled based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery, including:

[0010] When the ambient temperature (first temperature sensor) is less than or equal to the first preset temperature (-20℃) and the SOC of the power battery is less than the first preset SOC (50%), the fuel cell is controlled to start with the first preset operating strategy (pump stop warm-up);

[0011] When the ambient temperature (first temperature sensor) is less than or equal to a first preset temperature (-20℃) and the SOC of the power battery is greater than or equal to a first preset SOC (50%), to address the issue of insufficient power generation and storage during the cold start of the fuel cell system due to the reduced charging power of the power battery in low-temperature environments, the PTC1 heater, the PTC2 heater, and the PTC3 heater are activated, and the fuel cell is started using a first preset operating strategy (pump-off warm-up). This process not only consumes excess discharge during the cold start of the fuel cell but also accelerates the vehicle's thermal management to reach the ideal operating temperature through the electric heaters.

[0012] Among them, the pump shutdown and warm-up cold start strategy utilizes the self-heating of the fuel cell stack to raise the temperature, and the lowest single-unit voltage closed-loop adaptive current load avoids reverse polarity (fuel cell stack single-unit voltage U<0V). Based on the gas outlet temperature mapping result, the water pump is turned on in a timely manner to utilize heat generation and avoid thermal runaway, supporting non-destructive rapid start-up from -20℃ to -30℃, and extending the low-temperature service life of the gas-fired power system.

[0013] Furthermore, controlling the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery also includes:

[0014] When the ambient temperature (first temperature sensor) is greater than the first preset temperature (-20℃) and the SOC of the power battery is less than the second preset SOC (70%), the fuel cell is controlled to start with the second preset operating strategy (high current load).

[0015] Among them, the high-current load cold start strategy increases the stack's cold start current and reduces the average cold start voltage of the fuel cell, thereby increasing the heat generated by the stack.

[0016] In the first preset operation strategy and the second preset operation strategy, the total power generation of the engine corresponding to the fuel cell is controlled to be a preset power generation and the maximum power generation is a preset power generation. The preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy, and the preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy.

[0017] In step S2, controlling the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery further includes:

[0018] After the fuel cell is started with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is less than or equal to the third preset SOC (30%), the fuel cell is controlled to operate with the third preset operating strategy (fuel cell high-efficiency charging).

[0019] The efficient charging operation strategy of the gas-electric system means that during the vehicle's operation, the gas-electric system operates at its rated power, and the electricity generated is used to power the drive motor, PTC heater, and power battery.

[0020] Furthermore, the fuel cell is controlled to operate according to a third preset operating strategy, including:

[0021] Control the first PCT heater and the second PCT heater to shut down;

[0022] Acquire the temperature of the cockpit thermal management system (second temperature sensor);

[0023] When the temperature of the vehicle's environmental thermal management system is greater than or equal to the second preset temperature (65°C), the main radiator in the fuel cell thermal management system is controlled to operate.

[0024] When the temperature of the vehicle's environmental thermal management system is lower than the second preset temperature (65°C), the first liquid-liquid heat exchanger is kept in operation, and the second liquid-liquid heat exchanger is controlled to operate.

[0025] Obtain the temperature of the vehicle's power battery system;

[0026] When the temperature of the power battery system is lower than the third preset temperature (0℃), the PTC3 heater is started; when the temperature of the power battery system is greater than or equal to the fourth preset temperature (30℃), the second liquid-liquid heat exchanger is stopped. The purpose here is to heat the power battery as soon as possible to reach the high-efficiency operating temperature and avoid the increase in internal resistance of the power battery and the serious reduction in discharge efficiency caused by low temperature conditions.

[0027] In the third preset operation strategy, in addition to controlling the PTC, it is also necessary to control the solenoid valve to control the operation of the first liquid-liquid heat exchanger and the second liquid-liquid heat exchanger to avoid excessive heat exchange and thermal runaway of the power battery.

[0028] In step S2, controlling the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery further includes:

[0029] After the fuel cell is started with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is greater than the third preset SOC (30%), or if the fuel cell is running with the third preset operating strategy and the SOC of the power battery is greater than the fourth preset SOC (50%), then the fuel cell is controlled to run with the fourth preset operating strategy (idling and heat preservation).

[0030] Under the idling and heat preservation operation strategy, the fuel cell system operates in its highest efficiency range, generating current to power the vehicle, replenish the battery, or supply electrical components. The heat generated is sufficient to meet the heating needs of the cabin and battery. Under this condition, the fuel cell electric vehicle exhibits optimal economy.

[0031] Furthermore, controlling the fuel cell to operate according to a fourth preset operating strategy includes:

[0032] Acquire the temperature of the cockpit thermal management system (second temperature sensor);

[0033] When the temperature of the vehicle environment thermal management system is lower than the fifth preset temperature (60°C), the PTC1 heater is controlled to start and the first liquid-liquid heat exchanger is kept in operation.

[0034] Obtain the temperature of the power battery thermal management system;

[0035] When the temperature of the power battery thermal management system is lower than the sixth preset temperature (30°C), the PTC2 heater is activated.

[0036] When the temperature of the power battery thermal management system is greater than or equal to the sixth preset temperature, the PTC2 heater is controlled to shut down, and the second liquid-liquid heat exchanger is controlled to operate.

[0037] The temperature of the vehicle's power battery system is obtained;

[0038] When the temperature of the power battery system is lower than the seventh preset temperature (0°C), the PTC3 heater is activated.

[0039] When the temperature of the power battery system is greater than or equal to the eighth preset temperature (30°C), the second liquid-liquid heat exchanger is controlled to stop working.

[0040] Another object of the present invention is to provide a low-temperature environment thermal management device for fuel cell vehicles, which implements the low-temperature environment thermal management method for fuel cell vehicles as described above, and the low-temperature environment thermal management device for fuel cell vehicles includes an acquisition module and a control module.

[0041] The acquisition module is used to acquire the ambient temperature (first temperature sensor) and the vehicle's power battery SOC;

[0042] The control module is used to control the operation strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater and the fuel cell based on the ambient temperature (first temperature sensor) and the SOC of the power battery, so as to utilize the waste heat generated by the operation of the fuel cell;

[0043] The vehicle includes a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system (second temperature sensor) are connected via a first liquid-liquid heat exchanger, and the cockpit thermal management system (second temperature sensor) and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system (second temperature sensor) includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater.

[0044] Another object of the present invention is to provide a vehicle equipped with the aforementioned fuel cell vehicle low-temperature thermal management device.

[0045] Combining all the above technical solutions, the beneficial effects of this invention are as follows:

[0046] The vehicle provided by this invention includes a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system (second temperature sensor) are connected via a first liquid-liquid heat exchanger, and the cockpit thermal management system (second temperature sensor) and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system (second temperature sensor) includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater. The method includes: acquiring the ambient temperature (first temperature sensor) and the state of charge (SOC) of the vehicle's power battery; controlling the operating strategies of each PTC heater and the fuel cell based on the ambient temperature (first temperature sensor) and the power battery SOC to fully utilize the waste heat generated by the fuel cell operation, improve the environmental compatibility and service life of the fuel cell, achieve overall vehicle energy balance, and extend the service life of the fuel cell and the driving range of the vehicle.

[0047] The present invention provides a significant improvement in the winter driving range of fuel cell vehicles, effectively alleviating the range anxiety of new energy vehicles in winter. Currently, there is no integrated thermal management fuel cell vehicle configuration solution in China that covers the fuel cell system, cockpit, and power battery. The present invention further optimizes the utilization of fuel cell waste heat, improves the operating temperature of the power battery, and enhances the overall vehicle operating efficiency. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure;

[0049] Figure 1 This is a schematic diagram illustrating the connection principle between various thermal management systems in a vehicle according to an embodiment of the present invention;

[0050] Figure 2 This is a flowchart of a low-temperature thermal management method for fuel cell vehicles provided in an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the discharge efficiency of a power battery in a specific embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of the charging efficiency of a power battery in a specific embodiment of the present invention;

[0053] Figure 5 This is a flowchart illustrating the control strategy for the operation of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature (first temperature sensor) and the SOC of the power battery, according to a specific embodiment of the present invention.

[0054] Figure 6 This is a flowchart of a specific embodiment of the present invention for controlling a fuel cell to operate according to a third preset operating strategy;

[0055] Figure 7 This is a flowchart illustrating the control of the fuel cell to operate according to a fourth preset operating strategy, based on a specific embodiment of the present invention.

[0056] Figure 8 This is a block diagram of the low-temperature environment thermal management device for fuel cell vehicles in an embodiment of the present invention;

[0057] Figure 9 This is a vehicle structure block diagram according to an embodiment of the present invention;

[0058] Figure 10 This is a schematic diagram illustrating the principle of low-temperature thermal management for fuel cell vehicles provided in this embodiment of the invention:

[0059] Figure 11 This is a comparative analysis chart of driving range provided in an embodiment of the present invention;

[0060] Figure 12a This is a schematic diagram illustrating the working principle of the pump shutdown, warm-up, and cold start strategy provided in this embodiment of the invention. Figure 12b This is a power change diagram of the pump stop warm-up cold start strategy diagram provided in the embodiment of the present invention; Figure 12c This is a voltage change diagram of the pump shutdown warm-up cold start strategy diagram provided in the embodiment of the present invention; Figure 12d This is a temperature change diagram of the pump shutdown warm-up cold start strategy diagram provided in the embodiment of the present invention;

[0061] Figure 13 This is a diagram of a high-current load cold start strategy provided in an embodiment of the present invention; wherein, Figure (a) is a current change diagram, Figure (b) is a temperature change diagram, and Figure (c) is a power change diagram;

[0062] In the diagram: 800, thermal management device for low-temperature environment of fuel cell vehicle; 801, acquisition module; 802, control module; 900, vehicle. Detailed Implementation

[0063] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0064] The innovation of this invention lies in the fact that the waste heat generated by the fuel cell during operation accounts for approximately 50% of the total energy consumption. Utilizing this waste heat for air conditioning heating and power battery heating effectively improves energy utilization efficiency. In winter applications of fuel cell electric vehicles, the heat generated by the fuel cell is used to heat the air conditioning and power battery cooling circuits via a heat exchanger. This waste heat enables the cabin air conditioning heating function while keeping the power battery operating within its optimal temperature range (e.g., 0°C to 30°C), improving fuel cell power generation efficiency, extending the vehicle's winter driving range, reducing winter power consumption, and significantly improving the user experience. Furthermore, the timing of fuel cell system startup and shutdown under low-temperature conditions in FC-PHEV and FC-REEV, as well as related cold-start strategies, must fully consider the impact of cold-start ambient temperature and vehicle energy management requirements. For example: 1. Selecting different cold-start strategies under different low-temperature environments ensures a high success rate for cold starts and reduces the impact on stack lifespan; 2. Considering the impact of low temperature and SOC value on the power battery's charge / discharge rate and capacity, timely starting of fuel cell charging is implemented, coordinating with power-consuming components such as the PTC to achieve vehicle energy balance. A schematic diagram of the innovative principle is shown below. Figure 10 As shown.

[0065] Example 1, as Figure 1 As shown in the embodiment of the present invention, the connection principle between the various thermal management systems of a vehicle includes a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system (second temperature sensor) are connected by a first liquid-liquid heat exchanger (i.e., Figure 1 The first liquid-liquid heat exchanger in the middle is connected;

[0066] The cockpit thermal management system (second temperature sensor) and the power battery thermal management system are connected by a second liquid-liquid heat exchanger (i.e. Figure 1 The second liquid-liquid heat exchanger in the system is connected, and the fuel cell management system includes a PTC1 heater (i.e., Figure 1 The PTC1 in the cockpit thermal management system (second temperature sensor) includes a PTC2 heater (i.e. Figure 1 The power battery thermal management system includes a PTC3 heater (i.e., PTC2 in the PTC2). Figure 1 (PTC3 in the text). Additionally, other components in each thermal management system and their connection methods can be found in [reference needed]. Figure 1 .

[0067] like Figure 2 As shown, a thermal management method for fuel cell vehicles in low-temperature environments includes:

[0068] S1, acquire the ambient temperature monitored by the first temperature sensor, the vehicle's power battery SOC, and the cabin's heating temperature requirements.

[0069] S2 determines the fuel cell start-up requirements based on ambient temperature and the SOC of the power battery. Based on these requirements, it controls the PTC1 heater and the fuel cell system's operating strategy, selecting cold start, thermal management, and energy management strategies to achieve a non-destructive, low-temperature cold start while utilizing the waste heat generated during fuel cell operation. Based on the cabin heating requirements and the utilization of fuel cell waste heat, it determines the operating control strategy for the second PCT heater, using waste heat from the fuel cell system to heat the cabin and reduce electric heating energy consumption. Based on the power battery's thermal management requirements and the utilization of fuel cell waste heat, it controls the operating strategy of the PTC3 heater to support the power battery in quickly reaching the target operating temperature, improving power battery discharge efficiency and reducing electric heating energy consumption.

[0070] For example, the vehicle in this embodiment of the invention includes multiple thermal management systems, specifically including a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. Each thermal management system is connected through a heat exchanger and is equipped with a PTC heater. The thermal management method of this vehicle controls the operating strategies of each PTC heater and the fuel cell based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the vehicle's power battery to ensure that the preheating generated by the operation of the fuel cell can be fully utilized, thereby improving the environmental compatibility and service life of the fuel cell, achieving overall vehicle energy balance, extending the service life of the fuel cell, and increasing the vehicle's driving range.

[0071] For example, specifically, ambient temperature (the first temperature sensor) affects the discharge efficiency of the power battery's state of charge (SOC) and also its charging power. See [link to relevant documentation] for details. Figure 3 and Figure 4 As shown, the lower the temperature, the lower the discharge efficiency and the lower the charging power.

[0072] After obtaining the ambient temperature (first temperature sensor) and the SOC of the power battery, the PTC1 heater, PTC2 heater and PTC3 heater can be controlled according to the ambient temperature (first temperature sensor) and the SOC of the power battery. At the same time, the operation strategy of the fuel cell will also be controlled, with the aim of making full use of the preheating generated by the operation of the fuel cell.

[0073] For example, such as Figure 5 As shown, in step S2, the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell are controlled based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery, including:

[0074] When the ambient temperature (first temperature sensor) is less than or equal to the first preset temperature (-20℃) and the SOC of the power battery is less than the first preset SOC (50%), the fuel cell is controlled to start with the first preset operating strategy (pump stop warm-up);

[0075] When the ambient temperature (first temperature sensor) is less than or equal to a first preset temperature (-20℃) and the SOC of the power battery is greater than or equal to a first preset SOC (50%), to address the issue of insufficient power generation and storage during the cold start of the fuel cell system due to the reduced charging power of the power battery in low-temperature environments, the PTC1 heater, the PTC2 heater, and the PTC3 heater are activated, and the fuel cell is started using a first preset operating strategy (pump-off warm-up). This process not only consumes excess discharge during the cold start of the fuel cell but also accelerates the vehicle's thermal management to reach the ideal operating temperature through the electric heaters.

[0076] Among them, the pump shutdown and warm-up cold start strategy makes full use of the self-heating of the fuel cell stack, and the lowest single-unit voltage closed-loop adaptive current load avoids reverse polarity (fuel cell stack single-unit voltage U<0V). Based on the gas outlet temperature mapping result, the water pump is turned on in a timely manner to make full use of heat generation and avoid thermal runaway. It supports non-destructive rapid start-up from -20℃ to -30℃, and extends the low-temperature service life of the gas-fired power system. Its schematic diagram and measured data diagram are shown in Figure 12.

[0077] In another specific example, if the ambient temperature (first temperature sensor) is determined to be less than or equal to a first preset temperature, which could be -20°C, and the SOC of the power battery is less than the first preset SOC, it indicates that the ambient temperature (first temperature sensor) is low and the SOC of the power battery is also low, which could be 50%. Therefore, the fuel cell can be controlled to start with a first preset operating strategy, which could be a pump-stop warm-up start-up method. However, if the ambient temperature (first temperature sensor) is less than or equal to the first preset temperature and the SOC of the power battery is greater than or equal to the first preset SOC, it indicates that the ambient temperature (first temperature sensor) is low, but the SOC of the power battery is not low. Therefore, the three PTCs can be started first, and then the fuel cell can be controlled to start with the first preset operating strategy. In this embodiment, the total power generation corresponding to the first preset operating strategy can be 0.5 kWh, and the maximum power generation can be 45 kW.

[0078] For example, such as Figure 5 As shown, the operating strategy of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell is controlled based on the ambient temperature (first temperature sensor) and the state of charge (SOC) of the power battery, including:

[0079] When the ambient temperature (first temperature sensor) is greater than the first preset temperature (-20℃) and the SOC of the power battery is less than the second preset SOC (70%), the fuel cell is controlled to start with the second preset operating strategy (high current load).

[0080] Among them, the high-current load cold start strategy increases the stack's cold start current and reduces the average cold start voltage of the fuel cell, thereby increasing the stack's heat generation. The heat generation principle formula and measured results of this strategy are as follows: Figure 13 As shown.

[0081] In another specific example, when the ambient temperature (first temperature sensor) is greater than a first preset temperature and the power battery SOC is less than a second preset SOC, it indicates that the current ambient temperature (first temperature sensor) is not too low. Furthermore, in this embodiment, the second preset SOC can be set to 70%, which is greater than the first preset SOC. In this case, a second preset operating strategy can be used to start the power battery. This second preset operating strategy can be a high-capacity load start-up method. In this embodiment, the total power generation corresponding to the second preset operating strategy can be 0.4 kWh, and the maximum power generation can be 38 kW. It should be noted that when the ambient temperature (first temperature sensor) is greater than the first preset temperature and the power battery SOC is greater than or equal to the second preset SOC, a fuel cell pure electric drive engine can be used.

[0082] For example, in the first preset operation strategy and the second preset operation strategy, the total power generation of the engine corresponding to the fuel cell is controlled to be a preset power generation and the maximum power generation is a preset power generation. The preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy, and the preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy.

[0083] For example, such as Figure 5 As shown, the low-temperature thermal management method for fuel cell vehicles further includes:

[0084] After the fuel cell is started with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is less than or equal to the third preset SOC (30%), the fuel cell is controlled to operate with the third preset operating strategy (fuel cell high-efficiency charging).

[0085] The efficient charging operation strategy of the gas-electric system means that during the vehicle's operation, the gas-electric system operates at its rated power, and the electricity generated is used to power the drive motor, PTC heater, and power battery.

[0086] Specifically, during the operation of the fuel cell under the first and second preset operating strategies, it is also necessary to determine the SOC of the power battery. If the SOC of the power battery is less than or equal to the third preset SOC, which can be 30%, it indicates that the remaining power of the power battery is not very high. Therefore, it is necessary to control the fuel cell to operate under the third preset operating strategy to charge the power battery. The third preset strategy can be the ignition point high-efficiency charging method.

[0087] like Figure 6 As shown, the fuel cell is controlled to operate according to a third preset operating strategy, including:

[0088] Control the first PCT heater and the second PCT heater to shut down;

[0089] Acquire the temperature of the cockpit thermal management system (second temperature sensor);

[0090] When the temperature of the vehicle's environmental thermal management system is greater than or equal to the second preset temperature (65°C), the main radiator in the fuel cell thermal management system is controlled to operate.

[0091] When the temperature of the vehicle's environmental thermal management system is lower than the second preset temperature (65°C), the first liquid-liquid heat exchanger is kept in operation, and the second liquid-liquid heat exchanger is controlled to operate.

[0092] Obtain the temperature of the vehicle's power battery system;

[0093] When the temperature of the power battery system is lower than the third preset temperature (0℃), the PTC3 heater is started; when the temperature of the power battery system is greater than or equal to the fourth preset temperature (30℃), the second liquid-liquid heat exchanger is stopped. The purpose here is to heat the power battery as soon as possible to reach the high-efficiency operating temperature and avoid the increase in internal resistance of the power battery and the serious reduction in discharge efficiency caused by low temperature conditions.

[0094] In the third preset operation strategy, in addition to controlling the PTC, it is also necessary to control the solenoid valve to control the operation of the first liquid-liquid heat exchanger and the second liquid-liquid heat exchanger to avoid excessive heat exchange and thermal runaway of the power battery.

[0095] In the third preset operation strategy, in addition to controlling the PTC, it is also necessary to control the solenoid valve to control the operation of the first liquid-liquid heat exchanger and the second liquid-liquid heat exchanger. This is to ensure that the temperature of the fuel cell and the power battery does not drop too low during the charging process, thus affecting their use.

[0096] For example, such as Figure 5 As shown, the low-temperature thermal management method for fuel cell vehicles further includes:

[0097] After the fuel cell is started with a first preset operating strategy or a second preset operating strategy, if the SOC of the power battery is greater than a third preset SOC, or if the fuel cell is running with a third preset operating strategy and the SOC of the power battery is greater than a fourth preset SOC, then the fuel cell is controlled to run with a fourth preset operating strategy.

[0098] Another specific example is that after the fuel cell is started with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is greater than the third preset SOC, or if the fuel cell is running with the third preset operating strategy and the SOC of the power battery is greater than the fourth preset SOC, then it means that the fuel cell can be controlled by idling and heat preservation operation. The fourth preset temperature strategy is the idling and heat preservation operation mode, where the third preset SOC is 30% and the fourth preset SOC is 50%.

[0099] It should be noted that after the fuel cell executes the idling and heat preservation operation mode, the SOC of the power battery is further assessed. If the SOC of the power battery is less than or equal to 90%, the idling and heat preservation operation mode continues. If the SOC of the power battery is greater than 90%, the fuel cell system executes a normal temperature shutdown, and the water pump continues to run. Then, the temperature of the fuel cell is assessed. If the temperature of the fuel cell is greater than 15 degrees Celsius, the process returns to the step of determining whether the SOC of the power battery is less than the second preset SOC. If the temperature of the fuel cell is less than or equal to 15 degrees Celsius, and the SOC of the power battery is greater than 90%, the PTC1 heater can be turned on to consume electricity and generate heat, followed by the power-on-low temperature shutdown purging operation. If the SOC of the power battery is less than or equal to 90%, the power-on-low temperature shutdown purging operation is executed directly. In this embodiment, during the power-on-low temperature shutdown purging, the total power generation of the engine is 1 kWh, and the maximum power generation is 10 kW.

[0100] For example, such as Figure 7 As shown, controlling the fuel cell to operate according to a fourth preset operating strategy includes:

[0101] Acquire the temperature of the cockpit thermal management system (second temperature sensor);

[0102] When the temperature of the vehicle environment thermal management system is lower than the fifth preset temperature, the PTC1 heater is controlled to start and the first liquid-liquid heat exchanger is kept working.

[0103] Obtain the temperature of the power battery thermal management system;

[0104] When the temperature of the power battery thermal management system is lower than the sixth preset temperature, the PTC2 heater is activated.

[0105] When the temperature of the power battery thermal management system is greater than or equal to the sixth preset temperature, the PTC2 heater is controlled to shut down, and the second liquid-liquid heat exchanger is controlled to operate.

[0106] The temperature of the vehicle's power battery system (air compressor, electronic power box, etc.) is obtained;

[0107] When the temperature of the power battery system is lower than the seventh preset temperature, the PTC3 heater is activated.

[0108] When the temperature of the power battery system is greater than or equal to an eighth preset temperature, the second liquid-liquid heat exchanger is controlled to stop working.

[0109] In the fourth preset operation strategy, in addition to controlling the PTC, it is also necessary to control the solenoid valve to control the operation of the first liquid-liquid heat exchanger and the second liquid-liquid heat exchanger. This is to prevent the temperature of the fuel cell and the power battery from getting too low during the idling and heat preservation process of the fuel cell, which would affect its use, and also to ensure that other thermal management systems can supply heat normally.

[0110] In summary, the vehicle thermal management control method in this embodiment of the invention can improve the environmental compatibility and service life of fuel cells, achieve overall vehicle energy balance, extend the service life of fuel cells, and increase the vehicle's driving range.

[0111] Example 2, as Figure 8 As shown, a low-temperature environment thermal management device 800 for fuel cell vehicles is provided, with reference to... Figure 1 The vehicle includes a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system (second temperature sensor) are connected via a first liquid-liquid heat exchanger, and the cockpit thermal management system (second temperature sensor) and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system (second temperature sensor) includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater.

[0112] The low-temperature environment thermal management device 800 for fuel cell vehicles includes an acquisition module 801 and a control module 802. It includes:

[0113] The acquisition module 801 is used to acquire the ambient temperature (first temperature sensor) and the state of charge (SOC) of the vehicle's power battery;

[0114] The control module 802 is used to control the operation strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater and the fuel cell based on the ambient temperature (first temperature sensor) and the SOC of the power battery, so as to make full use of the waste heat generated by the operation of the fuel cell.

[0115] For example, the control module 802 is further configured to: control the fuel cell to start with a first preset operating strategy when the ambient temperature (first temperature sensor) is less than or equal to a first preset temperature and the power battery SOC is less than the first preset SOC; and control the PTC1 heater, PTC2 heater and PTC3 heater to start and control the fuel cell to start with the first preset operating strategy when the ambient temperature (first temperature sensor) is less than or equal to the first preset temperature and the power battery SOC is greater than or equal to the first preset SOC.

[0116] In some embodiments of the present invention, the control module 802 is further configured to: control the fuel cell to start with a second preset operating strategy when the ambient temperature (first temperature sensor) is greater than a first preset temperature and the power battery SOC is less than a second preset SOC.

[0117] In some embodiments of the present invention, the control module 802 is further configured to: after the fuel cell is started with a first preset operating strategy or a second preset operating strategy, if the SOC of the power battery is less than or equal to a third preset SOC, control the fuel cell to operate with a third preset operating strategy.

[0118] In some embodiments of the present invention, the control module 802 is further configured to: after the fuel cell is started with a first preset operating strategy or a second preset operating strategy, if the SOC of the power battery is greater than a third preset SOC, or after the fuel cell is running with a third preset operating strategy and the SOC of the power battery is greater than a fourth preset SOC, then control the fuel cell to run with a fourth preset operating strategy.

[0119] In some embodiments of the present invention, in the first preset operation strategy and the second preset operation strategy, the total power generation of the engine corresponding to the fuel cell is controlled to be a preset power generation and the maximum power generation is a preset power generation. The preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy, and the preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy.

[0120] In some embodiments of the present invention, the control module 802 is further configured to: control the first PCT heater and the second PCT heater to shut down; acquire the temperature of the cockpit thermal management system (second temperature sensor); control the main radiator in the fuel cell thermal management system to operate when the temperature of the vehicle ambient thermal management system is greater than or equal to a second preset temperature; maintain the operation of the first liquid-liquid heat exchanger and control the operation of the second liquid-liquid heat exchanger when the temperature of the vehicle ambient thermal management system is less than the second preset temperature; acquire the temperature of the vehicle's power battery system; control the PTC3 heater to start when the temperature of the power battery system is less than a third preset temperature; and control the second liquid-liquid heat exchanger to stop operating when the temperature of the power battery system is greater than or equal to a fourth preset temperature.

[0121] In some embodiments of the present invention, the control module 802 is further configured to: acquire the temperature of the cockpit thermal management system (second temperature sensor); when the temperature of the vehicle ambient thermal management system is less than a fifth preset temperature, control the PTC1 heater to start and maintain the operation of the first liquid-liquid heat exchanger; acquire the temperature of the power battery thermal management system; when the temperature of the power battery thermal management system is less than a sixth preset temperature, control the PTC2 heater to start; when the temperature of the power battery thermal management system is greater than or equal to the sixth preset temperature, control the PTC2 heater to shut down and control the second liquid-liquid heat exchanger to operate; acquire the temperature of the vehicle's power battery system; when the temperature of the power battery system is less than a seventh preset temperature, control the PTC3 heater to start; and when the temperature of the power battery system is greater than or equal to an eighth preset temperature, control the second liquid-liquid heat exchanger to stop operating.

[0122] It should be noted that the specific implementation of the vehicle thermal management control device in the embodiments of the present invention can be found in the specific implementation of the vehicle thermal management control method in the above embodiments. To avoid redundancy, it will not be described again here.

[0123] In summary, the vehicle thermal management control device of the present invention can improve the environmental compatibility and service life of fuel cells, achieve vehicle energy balance, extend the service life of fuel cells, and increase the driving range of the vehicle.

[0124] For example, the vehicle in this embodiment of the invention includes multiple thermal management systems, specifically including a fuel cell thermal management system, a cockpit thermal management system (second temperature sensor), and a power battery thermal management system. Each thermal management system is connected through a heat exchanger and is equipped with a PTC heater. The vehicle's thermal management device controls an acquisition module and a control module. The control module controls the operating strategies of each PTC heater and the fuel cell based on the ambient temperature (first temperature sensor) acquired by the acquisition module and the vehicle's power battery SOC, so as to ensure that the preheating generated by the operation of the fuel cell can be fully utilized, thereby improving the environmental compatibility and service life of the fuel cell, achieving overall vehicle energy balance, extending the service life of the fuel cell, and increasing the vehicle's driving range.

[0125] Example 3, as Figure 9 This invention provides a vehicle 900, including a low-temperature environment thermal management device 800 for fuel cell vehicles. Through the thermal management control device described above, the vehicle of this invention can improve the environmental compatibility and service life of the fuel cell, achieve overall vehicle energy balance, extend the service life of the fuel cell, and increase the vehicle's driving range.

[0126] like Figure 11 As shown, to further illustrate the effects of the embodiments of the present invention, the following simulation verification was performed, with the variables being ambient temperature and the state of charge (SOC) of the power battery. Simulations were conducted under different ambient temperatures (low temperatures) and power battery SOC values. The winter driving range of the fuel cell vehicle was significantly improved, as shown in Table 1.

[0127] Table 1 Simulation data under different ambient temperatures and power battery SOC values.

[0128]

[0129] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for thermal management in low-temperature environments for fuel cell vehicles, characterized in that, The method includes the following steps: S1, obtain the ambient temperature monitored by the first temperature sensor, the vehicle's power battery SOC, and the cabin's heating temperature requirements. S2 determines the fuel cell start-up requirements based on ambient temperature and the SOC of the power battery. Based on these requirements, it controls the PTC1 heater and the fuel cell system's operating strategy, selecting cold start, thermal management, and energy management strategies to achieve a non-destructive, low-temperature cold start while utilizing the waste heat generated during fuel cell operation. Based on the cabin heating requirements and the utilization of fuel cell waste heat, it determines the operating control strategy for the second PCT heater, using waste heat from the fuel cell system to heat the cabin and reduce electric heating energy consumption. Based on the power battery's thermal management requirements and the utilization of fuel cell waste heat, it controls the operating strategy of the PTC3 heater to support the power battery reaching its target operating temperature.

2. The low-temperature thermal management method for fuel cell vehicles according to claim 1, characterized in that, In step S1, the vehicle includes a fuel cell thermal management system, a cockpit thermal management system equipped with a second temperature sensor, and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system are connected through a first liquid-liquid heat exchanger. The cockpit thermal management system and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater.

3. The low-temperature thermal management method for fuel cell vehicles according to claim 1, characterized in that, In step S2, the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell are controlled based on the ambient temperature and the state of charge (SOC) of the power battery, including: When the ambient temperature monitored by the first temperature sensor is less than or equal to the first preset temperature, and the SOC of the power battery is less than 50% of the first preset SOC, the fuel cell is controlled to achieve pump stop warm-up start-up according to the first preset operating strategy. When the ambient temperature monitored by the first temperature sensor is less than or equal to the first preset temperature and the SOC of the power battery is greater than or equal to 50% of the first preset SOC, the PTC1 heater, the PTC2 heater and the PTC3 heater are controlled to start, and the fuel cell is controlled to start up with pump stop and warm-up according to the first preset operating strategy. Among them, the pump shutdown and warm-up cold start strategy utilizes the self-heating of the fuel cell stack to raise the temperature, the lowest unit voltage closed-loop adaptive current load avoids reverse polarity, and the water pump is turned on in a timely manner based on the gas outlet temperature mapping result to generate heat and avoid thermal runaway.

4. The low-temperature thermal management method for fuel cell vehicles according to claim 3, characterized in that, The control of the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature and the state of charge (SOC) of the power battery also includes: When the ambient temperature monitored by the first temperature sensor is greater than the first preset temperature and the SOC of the power battery is less than 70% of the second preset SOC, the fuel cell is controlled to start with high current load using the second preset operating strategy. In the first preset operation strategy and the second preset operation strategy, the total power generation of the engine corresponding to the fuel cell is controlled to be a preset power generation and the maximum power generation is a preset power generation. The preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy, and the preset power generation corresponding to the first preset operation strategy is greater than the preset power generation corresponding to the second preset operation strategy.

5. The low-temperature thermal management method for fuel cell vehicles according to claim 4, characterized in that, In step S2, controlling the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature and the SOC of the power battery further includes: After the fuel cell is started with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is less than or equal to 30% of the third preset SOC, the fuel cell is controlled to operate with the third preset operating strategy. The efficient charging operation strategy of the gas-electric system means that during the vehicle's operation, the gas-electric system operates at its rated power, and the electricity generated is used to power the drive motor, PTC heater, and power battery.

6. The low-temperature environment thermal management method for fuel cell vehicles according to claim 5, characterized in that, Controlling the fuel cell to operate according to a third preset operating strategy includes: Control the first PCT heater and the second PCT heater to shut down; Obtain the temperature from the second temperature sensor in the cockpit thermal management system; When the temperature of the vehicle's environmental thermal management system is greater than or equal to 65°C (the second preset temperature), the main radiator in the fuel cell thermal management system is controlled to operate. When the temperature of the vehicle's environmental thermal management system is less than 65°C of the second preset temperature, the first liquid-liquid heat exchanger is kept in operation, and the second liquid-liquid heat exchanger is controlled to operate. Obtain the temperature of the vehicle's power battery system; When the temperature of the power battery system is lower than the third preset temperature, the PTC3 heater is started; when the temperature of the power battery system is greater than or equal to the fourth preset temperature, the second liquid-liquid heat exchanger is stopped. The purpose here is to heat the power battery as soon as possible to reach the high-efficiency operating temperature and avoid the increase in internal resistance of the power battery and the serious reduction in discharge efficiency caused by low temperature conditions. In the third preset operation strategy, in addition to controlling the PTC, it is also necessary to control the solenoid valve to control the operation of the first liquid-liquid heat exchanger and the second liquid-liquid heat exchanger to avoid excessive heat exchange and thermal runaway of the power battery.

7. The low-temperature environment thermal management method for fuel cell vehicles according to claim 5, characterized in that, In step S2, controlling the operating strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater, and the fuel cell based on the ambient temperature and the SOC of the power battery further includes: After the fuel cell starts with the first preset operating strategy or the second preset operating strategy, if the SOC of the power battery is greater than 30% of the third preset SOC, or if the fuel cell operates with the third preset operating strategy and the SOC of the power battery is greater than 50% of the fourth preset SOC, then the fuel cell is controlled to operate with the fourth preset operating strategy to achieve idle temperature preservation. Under the idling and heat preservation operation strategy, the fuel cell system operates in the highest efficiency range, generating current to power the vehicle, replenish the power battery, or reduce electrical appliance losses.

8. The low-temperature environment thermal management method for fuel cell vehicles according to claim 7, characterized in that, Controlling the fuel cell to operate according to a fourth preset operating strategy includes: Obtain the temperature of the cockpit thermal management system; When the temperature of the vehicle environment thermal management system is lower than the fifth preset temperature, the PTC1 heater is controlled to start and the first liquid-liquid heat exchanger is kept working. Obtain the temperature of the power battery thermal management system; When the temperature of the power battery thermal management system is lower than the sixth preset temperature, the PTC2 heater is activated. When the temperature of the power battery thermal management system is greater than or equal to the sixth preset temperature, the PTC2 heater is controlled to shut down, and the second liquid-liquid heat exchanger is controlled to operate. The temperature of the vehicle's power battery system is obtained; When the temperature of the power battery system is lower than the seventh preset temperature, the PTC3 heater is activated. When the temperature of the power battery system is greater than or equal to an eighth preset temperature, the second liquid-liquid heat exchanger is controlled to stop working.

9. A thermal management device (800) for low-temperature environments of fuel cell vehicles, characterized in that, The device implements the low-temperature environment thermal management method for fuel cell vehicles as described in any one of claims 1-8, wherein the low-temperature environment thermal management device (800) for fuel cell vehicles includes an acquisition module (801) and a control module (802). The acquisition module (801) is used to acquire the ambient temperature and the SOC of the vehicle's power battery; The control module (802) is used to control the operation strategies of the PTC1 heater, the PTC2 heater, the PTC3 heater and the fuel cell according to the ambient temperature and the SOC of the power battery, so as to utilize the waste heat generated by the operation of the fuel cell; The vehicle includes a fuel cell thermal management system, a cockpit thermal management system, and a power battery thermal management system. The fuel cell thermal management system and the cockpit thermal management system are connected via a first liquid-liquid heat exchanger, and the cockpit thermal management system and the power battery thermal management system are connected via a second liquid-liquid heat exchanger. The fuel cell management system includes a PTC1 heater, the cockpit thermal management system includes a PTC2 heater, and the power battery thermal management system includes a PTC3 heater.

10. A vehicle (900), characterized in that, The vehicle is equipped with the fuel cell vehicle low-temperature environment thermal management device (800) as described in claim 9.

Images