Hydrogen heating system for a fuel cell vehicle and control method

Abstract

The application discloses a hydrogen heating system for vehicle fuel cells and a control method, and belongs to the technical field of fuel cells. The heating system comprises a hydrogen micro-channel heat exchanger, and a plurality of heating film pieces are fixedly arranged on the surface of the shell of the hydrogen micro-channel heat exchanger, and each heating film piece is provided with a temperature sensor. The heating film pieces are controlled by a fuel cell area controller (FCU) to be at a safe heating temperature, and a PTC heater is used to indirectly heat hydrogen in the hydrogen micro-channel heat exchanger, thereby assisting in improving hydrogen heating in a high-cold state. According to the ambient temperature, a heating mode (water full heating + film full heating, water half heating + film full heating, film full heating, and stable self-produced heat) is intelligently selected, water heating and film heating are coupled to heat, thereby reducing the parasitic power of the vehicle fuel cell in a low-temperature environment, improving the hydrogen and electricity safety of the fuel cell system, preventing the fuel cell stack from entering more liquid water, and improving the power generation performance and service life of the fuel cell.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically to a hydrogen heating system and control method for a vehicle fuel cell. Background Technology

[0002] Fuel cell electric vehicles use high-pressure gaseous hydrogen as an energy carrier. The hydrogen is stored in hydrogen storage cylinders with a rated pressure of 35 MPa or 70 MPa. It is then depressurized to 1.2-1.5 MPa by the onboard hydrogen system before entering the fuel cell system for electrochemical reactions. However, during the depressurization process, the hydrogen performs work and absorbs a significant amount of heat from the surrounding environment, resulting in the temperature of the fresh hydrogen entering the fuel cell being lower than ambient temperature. This is particularly problematic in high-altitude and cold-weather applications, where the hydrogen temperature inside the storage cylinders can approach -30°C or even lower. When the depressurized hydrogen enters the proportional valve or hydrogen injection solenoid valve inside the fuel cell system, the extremely low hydrogen temperature can cause the solenoid valve to malfunction, preventing the proper establishment of hydrogen inlet pressure and leading to fuel cell start-up failure in extreme cold conditions.

[0003] The optimal operating temperature for fuel cell systems is generally between 60-80℃. The temperatures of the hydrogen, air, and coolant entering the fuel cell stack must all fall within this range. However, fuel cells use excess hydrogen as the primary fuel. After the reaction, the remaining hydrogen passes through a hydrogen-water separator. The hot, humid circulating hydrogen mixes with the cold, fresh hydrogen inside the ejector tube, easily generating a large amount of liquid water droplets that enter the fuel cell stack. This can cause localized flooding, leading to serious faults such as low voltage on individual cells. Simultaneously, the cooler hydrogen reacts electrochemically with the warmer air across the proton exchange membrane. Due to the significant temperature difference, this can easily cause the proton exchange membrane to rupture, accelerating fuel cell lifespan degradation and even leading to irreversible damage.

[0004] Chinese invention patent application CN 118610509A discloses a fuel cell hydrogen heating device and vehicle. The fuel cell hydrogen heating device includes a base plate with heat exchange fins extending along a first and second direction. The heat exchange fins extending along the second direction are arranged in a layered heating structure, with placement channels between adjacent layers. A hydrogen pipeline for hydrogen transport is also included, reciprocating through the placement channels in the layered distribution direction. A fixing component for securing the hydrogen pipeline is provided on the base plate. A power generation component is detachably connected to the base plate for generating electricity. This patent utilizes the vehicle's own heat to heat the hydrogen pipeline, preventing liquid water in the hydrogen from entering the fuel cell's gas pipeline and clogging the gas path, thus ensuring the normal operation of the fuel cell. However, during the initial cold start of the fuel cell at low temperatures, the vehicle has not yet generated heat, or the heat generated by pure electricity is limited, resulting in excessively low hydrogen temperatures used in the fuel cell, causing start-up failure and failing to solve the technical problem of low-temperature cold start.

[0005] Chinese invention patent application CN 111322898A discloses a hydrogen heat exchanger for a hydrogen fuel cell and its usage method. The heat exchanger includes a heat exchange core, which comprises several spaced-apart compressed air channels and coolant channels. The two ends of the compressed air channels are connected to a compressed air inlet and a compressed air outlet, respectively, which are connected to a compressed air inlet and a compressed air outlet, respectively. The heat exchange core is located at the two ends of the coolant channels, which are connected to a coolant inlet and a coolant outlet, respectively, which are connected to a coolant inlet and a coolant outlet, respectively. A hydrogen pipe is installed inside the coolant outlet, with both its inlet and outlet extending outwards through the outlet. This patent heats the coolant with compressed air, and then uses the coolant to heat the hydrogen to a suitable temperature for use in the hydrogen fuel cell. However, this hydrogen heat exchanger has a small hydrogen heat exchange area and poor heat exchange effect, making it suitable only for use in lower ambient temperatures. However, there are still significant technical barriers in high-altitude and cold-weather applications, such as increased heat exchanger size, increased PTC water heater power, increased system integration size, and limited environmental applicability. Summary of the Invention

[0006] This invention provides a hydrogen heating system and control method for automotive fuel cells, aiming to solve the above-mentioned problems existing in current fuel cell hydrogen heating systems.

[0007] The present invention adopts the following technical solution:

[0008] A hydrogen heating system for a vehicle fuel cell includes a hydrogen microchannel heat exchanger. The heat medium channel of the hydrogen microchannel heat exchanger has a cooling medium inlet and a cooling medium outlet at both ends, and a hydrogen inlet and a hydrogen outlet at both ends of the refrigerant channel. The cooling medium inlet is connected to the rear end of the thermostat of the fuel cell stack cooling subsystem, and the cooling medium outlet is connected to the water pump inlet of the fuel cell stack cooling subsystem. The hydrogen inlet is connected to the on-board hydrogen system pipeline, and the hydrogen outlet is connected to a hydrogen proportional valve or a hydrogen injection solenoid valve. A plurality of heating diaphragms are fixedly mounted on the outer surface of the hydrogen microchannel heat exchanger, and each heating diaphragm is equipped with a temperature sensor. The heating diaphragms and the temperature sensors are electrically connected to the fuel cell domain controller (FCU).

[0009] In a preferred embodiment, the hydrogen gas flows in opposite directions in the heat medium channel and the cold medium channel of the hydrogen microchannel heat exchanger, with the cooling medium inlet corresponding to the hydrogen outlet and the cooling medium outlet corresponding to the hydrogen inlet.

[0010] In a preferred embodiment, the outer shell of the hydrogen microchannel heat exchanger has four surfaces, each of which is attached with a heating film.

[0011] In a preferred embodiment, the heating diaphragm is a flexible heating diaphragm, and a high-temperature adhesive is provided on the back of the heating diaphragm, which is highly attached to the outer surface of the hydrogen microchannel heat exchanger.

[0012] In a preferred embodiment, the heat medium pipeline of the hydrogen microchannel heat exchanger uses a deionized medium as the cooling medium, and the upper and lower layers of the heating diaphragm are both isolated by an insulating layer.

[0013] In a preferred embodiment, the outermost layer of the heating film is covered with flame-retardant sponge and then covered with aluminum foil.

[0014] This invention also provides a control method for hydrogen heating in a vehicle fuel cell, employing the aforementioned hydrogen heating system for a vehicle fuel cell, with the following specific steps:

[0015] S1. When the fuel cell domain controller (FCU) receives the stack start command, it performs a self-check to see if the basic conditions for stack start are met. If so, it starts the battery water pump and adjusts the thermostat so that the cooling medium flows through the "small circulation" channel.

[0016] S2. Determine if the ambient temperature T0 is below -20℃. If yes, activate the "full water heating + full membrane heating" mode. The PTC heater will operate at maximum power, and all heating membranes will operate at maximum power. If not, proceed to S3.

[0017] S3. Determine if the ambient temperature T0 is below -10℃. If so, activate the "half-heating water + full-heating membrane" mode. The PTC heater will operate at half heating power, and all heating membranes will operate at maximum power. If not, proceed to S4.

[0018] S4. Determine if the ambient temperature T0 is below 2℃. If so, turn on the "full membrane heating" mode. The PTC heater is in the off state, and all heating membranes are running at maximum power.

[0019] S5. When the fuel cell stack outlet water temperature T1 exceeds -10℃ and the hydrogen temperature T3 exceeds 10℃, the FCU executes the normal stack start-up process.

[0020] S6. Determine if the outlet water temperature T1 exceeds 50℃. If so, the cooling medium will start circulating through the "large circulation" channel. When the outlet water temperature T1 is in the range of 50-55℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 55-58℃, the thermostat opening y increases by 4% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 58-60℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature exceeds 60℃, the thermostat will no longer change.

[0021] Specifically, the aforementioned "small circulation" channel refers to the path from the water pump to the PTC heater, through the thermostat to the fuel cell stack and hydrogen microchannel heat exchanger, and finally back to the water pump inlet; the "large circulation" channel refers to the path from the water pump to the radiator, through the thermostat to the fuel cell stack and hydrogen microchannel heat exchanger, and finally back to the water pump inlet.

[0022] Furthermore, in steps S3, S4, or S5 above, when the temperature of any heating membrane exceeds 60°C, the power relay pulse width (PWM) of the heating membrane is reduced via the fuel cell domain controller (FCU). The PWM is reduced by 6% at a rate that prevents overheating of the heating membrane if the temperature exceeds 2°C. If the heating membrane temperature is detected to be below 60°C again, the PWM is increased by 4% at a rate that ensures the heating membrane remains at a constant temperature of 60°C if the temperature is below 2°C. If the hydrogen temperature sensor T3 exceeds 30°C, the PTC heater is shut down, switching to the "full membrane heating" single mode. If the hydrogen temperature sensor T3 exceeds 45°C, the heating membrane stops working, switching to the fuel cell "stable self-heating" mode.

[0023] Furthermore, in step S6 above, if the fuel cell controller FCU detects that the ambient temperature exceeds 30°C, the above thermostats will increase their opening by 2% respectively.

[0024] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention involves attaching multiple flexible heating films to the outer surface of a hydrogen microchannel heat exchanger. The heating films are kept at a safe heating temperature by a fuel cell domain controller (FCU), achieving a highly efficient and rapid hydrogen heating solution. Simultaneously, a PTC water heater is used to indirectly heat hydrogen inside the hydrogen microchannel heat exchanger, further enhancing hydrogen heating in extremely cold conditions (ambient temperature < -20℃). This avoids long heating times and poor heat preservation, while also being compatible with existing water heating technologies in the industry.

[0026] 2. This invention can intelligently select four heating modes ("full water heating + full membrane heating", "partial water heating + full membrane heating", "full membrane heating", "stable self-generated heat") according to the ambient temperature, realizing a coupled heating control scheme of water heating and membrane heating, thereby reducing the parasitic power of vehicle fuel cells operating in low-temperature environments. It can also adaptively adjust the hydrogen heating power according to the temperature of the fuel cell stack, improve the hydrogen safety inside the fuel cell system, prevent excessive liquid water from entering the fuel cell stack, and improve the power generation performance and service life of the fuel cell. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the hydrogen heating system for the fuel cell of the present invention.

[0028] Figure 2 This is a schematic diagram of the hydrogen microchannel heat exchanger of the present invention.

[0029] Figure 3 for Figure 2 A schematic diagram of its breakdown.

[0030] Figure 4 This is a schematic flowchart of the hydrogen heating control method for fuel cells of the present invention. Detailed Implementation

[0031] Specific embodiments of the present invention will now be described with reference to the accompanying drawings. Many details are described below to provide a comprehensive understanding of the invention; however, those skilled in the art will not need these details to implement the invention. Well-known components, methods, and processes will not be described in detail below.

[0032] This embodiment provides a hydrogen heating system for a vehicle fuel cell, referring to... Figure 1This includes a hydrogen microchannel heat exchanger 10 installed in the fuel cell system. The fuel cell system includes a fuel cell stack, an air circuit subsystem, a hydrogen circuit subsystem, and a stack cooling subsystem. The air circuit subsystem is a common subsystem in fuel cells in this field and is not the focus of this solution; therefore, it will not be described in detail here. The hydrogen circuit subsystem includes: an on-board hydrogen system 21, a hydrogen proportioning valve 22 (or a hydrogen injection solenoid valve), an ejector 23, a gas-liquid separator 24, a drain solenoid valve 25, and a tailpipe 26. The stack cooling subsystem includes: a water pump 31, a radiator 32, a PTC heater 33, and a thermostat 34.

[0033] The hydrogen microchannel heat exchanger 10 uses microchannel technology to maximize the specific surface area per unit volume, resulting in the largest heat exchange area (more than ten times that of a shell-and-tube heat exchanger). It is made by overlapping dozens of core plates and welding them under high temperature and high pressure in a vacuum environment.

[0034] Reference Figure 2 The hydrogen microchannel heat exchanger 10 described above has a cooling medium inlet 11 and a cooling medium outlet 12 at both ends of the heat medium channel, and a hydrogen inlet 13 and a hydrogen outlet 14 at both ends of the refrigerant channel. The internal media of the heat medium channel and the refrigerant channel have opposite directions. The cooling medium inlet 11 of the heat medium channel corresponds to the hydrogen outlet 14, and the cooling medium outlet 12 of the heat medium channel corresponds to the hydrogen inlet 13, which improves the heat exchange efficiency. At the same time, in order to be more compactly arranged inside the fuel cell system, the cooling medium inlet 11 and the hydrogen inlet 13 are arranged perpendicularly, which facilitates the centralized arrangement of pipelines in two directions.

[0035] Reference Figure 2 and Figure 3 The outer shell of the aforementioned hydrogen microchannel heat exchanger 10 is fixedly provided with several heating films 15. Specifically, the outer shell of the hydrogen microchannel heat exchanger has four surfaces, each of which is covered with a heating film 15. The heating films 15 are preferably flexible heating films. Except for the requirements of pipeline interface arrangement, the area of ​​the heating film 15 is kept as consistent as possible with the surface area of ​​the microchannel to effectively increase the heat exchange area. In addition, the back of the heating film is covered with high-temperature adhesive, which adheres closely to the surface of the heat exchanger to improve heating uniformity.

[0036] Considering that the heat transfer medium is a deionized medium and must flow through the inside of the fuel cell stack, there may be a problem with low insulation value when passing through the hydrogen microchannel heat exchanger. Therefore, insulation layers are used to isolate the upper and lower layers of the heating membrane. The upper layer is to prevent relevant personnel from touching it, and the lower layer is to prevent the risk of the coolant insulation value from decreasing. At the same time, it meets the requirements of high insulation strength and high heat conduction efficiency.

[0037] Each heating diaphragm 15 is equipped with a temperature sensor to detect the surface temperature of the heating diaphragm in real time and to provide over-temperature protection. The heating power harness of the heating diaphragm 15 and the temperature sensor sampling harness are led out by welding and adhesive bonding, connected to the fuel cell domain controller (FCU) for data acquisition, and the heating temperature is adjusted in real time by software. To prevent heat loss, after the heating diaphragm 15 is attached to the hydrogen microchannel heat exchanger 10, the outermost layer is covered with a 20mm thick flame-retardant sponge (not shown in the figure), and then covered with aluminum foil. It is then fixed to the sheet metal shell of the fuel cell system with bolts.

[0038] Reference Figure 1 and Figure 2 The hydrogen inlet 13 is connected to the pipeline of the on-board hydrogen system 21. The hydrogen pressure is 13±2 bar, and the hydrogen temperature is close to the ambient temperature. However, due to prolonged pressure reduction and heat absorption, the hydrogen temperature may be lower than the ambient temperature. The hydrogen outlet 14 is connected to the hydrogen proportional valve 22 (or the hydrogen injection solenoid valve). Pressure reduction is achieved through the hydrogen proportional valve 22 or the hydrogen injection solenoid valve. A hydrogen temperature sensor T3 is installed in the middle.

[0039] Reference Figure 1 and Figure 2 The hydrogen from the fuel cell stack hydrogen outlet passes through the gas-liquid separator 24 and is then thoroughly mixed with the hydrogen heated by the hydrogen microchannel heat exchanger 10 inside the ejector 23 before being injected into the fuel cell stack hydrogen inlet. A drain solenoid valve 25 is located at the lower end of the gas-liquid separator 24, which pulses to release moisture from the hydrogen, preventing the cold hydrogen from mixing with the hydrogen heated by the hydrogen microchannel heat exchanger 10 to produce liquid water that could clog the ejector and the gas chambers inside the fuel cell stack.

[0040] Reference Figure 1 and Figure 2 The aforementioned cooling medium inlet 11 is connected to the rear end of the thermostat 34 of the fuel cell stack cooling subsystem and is connected in parallel with the fuel cell stack cooling medium pipeline. The cooling medium outlet 12 is connected to the inlet of the water pump 31 of the fuel cell stack cooling subsystem. When the cooling medium temperature is detected to be relatively low, the cooling medium follows a "small circulation" channel: from the water pump 31 to the PTC heater 33, through the thermostat 34 to the fuel cell stack and the hydrogen microchannel heat exchanger 10, and finally back to the inlet of the water pump 31. When the cooling medium temperature is relatively high, the cooling medium follows a "large circulation" channel: from the water pump 31 to the radiator 32, through the thermostat 34 to the fuel cell stack and the hydrogen microchannel heat exchanger 10, and finally back to the inlet of the water pump 31.

[0041] The control method for the hydrogen heating system of the above-mentioned vehicle fuel cell is referred to Figure 4 Specifically, it includes the following steps:

[0042] S1. When the fuel cell domain controller (FCU) receives the stack start command, it performs a self-check to see if the basic conditions for stack start are met. If so, it starts the battery water pump and adjusts the thermostat so that the cooling medium flows through the "small circulation" channel.

[0043] S2. Determine if the ambient temperature T0 is below -20℃. If yes, activate the "full water heating + full membrane heating" mode. The PTC heater will operate at maximum power, and all heating membranes will operate at maximum power. If not, proceed to S3.

[0044] S3. Determine if the ambient temperature T0 is below -10℃. If so, activate the "half-heating water + full-heating membrane" mode. The PTC heater will operate at half heating power, and all heating membranes will operate at maximum power. If not, proceed to S4.

[0045] S4. Determine if the ambient temperature T0 is below 2℃. If so, turn on the "full membrane heating" mode. The PTC heater is in the off state, and all heating membranes are running at maximum power.

[0046] S5. When the fuel cell stack outlet water temperature T1 exceeds -10℃ and the hydrogen temperature T3 exceeds 10℃, the FCU executes the normal stack start-up process.

[0047] S6. Determine if the outlet water temperature T1 exceeds 50℃. If so, the cooling medium will start circulating through the "large circulation" channel. When the outlet water temperature T1 is in the range of 50-55℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 55-58℃, the thermostat opening y increases by 4% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 58-60℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature exceeds 60℃, the thermostat will no longer change.

[0048] In steps S2, S3, or S4 above, when the temperature of any heating membrane exceeds 60°C, the power relay pulse width (PWM) of the heating membrane is reduced via the fuel cell domain controller (FCU). The PWM is reduced by 6% at a rate that prevents overheating of the heating membrane if the temperature exceeds 2°C. If the heating membrane temperature is detected to be below 60°C again, the PWM is increased by 4% at a rate that ensures the heating membrane remains at a constant temperature of 60°C if the temperature is below 2°C. If the hydrogen temperature sensor T3 exceeds 30°C, the PTC heater is shut down, switching to the "full membrane heating" single mode. If the hydrogen temperature sensor T3 exceeds 45°C, the heating membrane stops working, switching to the fuel cell "stable self-heating" mode.

[0049] In step S6 above, if the fuel cell controller FCU detects that the ambient temperature exceeds 30°C, the above electronic thermostats will increase their opening by 2% to improve the adaptive ability of the fuel cell to dissipate heat from the ambient temperature.

[0050] Since the storage temperature of liquid hydrogen reaches -253°C, after the gaseous evaporation inside the liquid hydrogen storage and supply system, the hydrogen is in a low-temperature gaseous state. At this time, the hydrogen still needs to be further heated by the fuel cell system. Therefore, the hydrogen heating solution provided by this invention is also applicable to the on-board liquid hydrogen storage and supply system.

[0051] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A control method for hydrogen heating in a vehicle fuel cell, characterized in that: A hydrogen heating system for a vehicle fuel cell is disclosed. The system includes a hydrogen microchannel heat exchanger. The heat medium channel of the hydrogen microchannel heat exchanger has a cooling medium inlet and a cooling medium outlet at both ends, and a hydrogen inlet and a hydrogen outlet at both ends of the refrigerant channel. The cooling medium inlet is connected to the rear end of the thermostat of the fuel cell stack cooling subsystem, and the cooling medium outlet is connected to the water pump inlet of the fuel cell stack cooling subsystem. The hydrogen inlet is connected to the on-board hydrogen system pipeline, and the hydrogen outlet is connected to a hydrogen proportional valve or a hydrogen injection solenoid valve. Several heating diaphragms are fixedly mounted on the outer surface of the hydrogen microchannel heat exchanger. Each heating diaphragm is equipped with a temperature sensor, and the heating diaphragms and temperature sensors are electrically connected to the fuel cell domain controller (FCU). The specific steps are as follows: S1. When the fuel cell domain controller (FCU) receives the stack start command, it performs a self-check to see if the basic conditions for stack start are met. If so, it starts the battery water pump and adjusts the thermostat so that the cooling medium flows through the "small circulation" channel. S2. Determine if the ambient temperature T0 is below -20℃. If yes, activate the "full water heating + full membrane heating" mode. The PTC heater will operate at maximum power, and all heating membranes will operate at maximum power. If not, proceed to S3. S3. Determine if the ambient temperature T0 is below -10℃. If yes, activate the "half-heating water + full-heating membrane" mode. The PTC heater will operate at half heating power, and all heating membranes will operate at maximum power. If not, proceed to S4. S4. Determine if the ambient temperature T0 is below 2℃. If so, turn on the "full membrane heating" mode. The PTC heater is in the off state, and all heating membranes are running at maximum power. S5. When the fuel cell stack outlet water temperature T1 exceeds -10℃ and the hydrogen temperature T3 exceeds 10℃, the FCU executes the normal stack start-up process. S6. Determine if the outlet water temperature T1 exceeds 50℃. If so, the cooling medium will start circulating through the "large circulation" channel. When the outlet water temperature T1 is in the range of 50-55℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 55-58℃, the thermostat opening y increases by 4% for every 1℃ increase in water temperature. When the outlet water temperature T1 is in the range of 58-60℃, the thermostat opening y increases by 2% for every 1℃ increase in water temperature. When the outlet water temperature exceeds 60℃, the thermostat will no longer change.

2. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: The hydrogen microchannel heat exchanger has opposite directions of flow between the heat medium channel and the hydrogen in the cold medium channel. The cooling medium inlet corresponds to the hydrogen outlet, and the cooling medium outlet corresponds to the hydrogen inlet.

3. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: The outer shell of the hydrogen microchannel heat exchanger has four surfaces, each of which is attached with a heating film.

4. The control method for hydrogen heating in a vehicle fuel cell as described in claim 3, characterized in that: The heating diaphragm is a flexible heating diaphragm, and a high-temperature adhesive is provided on the back of the heating diaphragm, which is highly attached to the outer surface of the hydrogen microchannel heat exchanger.

5. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: The heat transfer medium of the hydrogen microchannel heat exchanger uses a deionized medium as the cooling medium, and the upper and lower layers of the heating diaphragm are both insulated.

6. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: The outermost layer of the heating diaphragm is covered with flame-retardant sponge and then covered with aluminum foil.

7. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: The "small circulation" channel refers to the path from the water pump to the PTC heater, through the thermostat to the fuel cell stack and hydrogen microchannel heat exchanger, and finally back to the water pump inlet; the "large circulation" channel refers to the path from the water pump to the radiator, through the thermostat to the fuel cell stack and hydrogen microchannel heat exchanger, and finally back to the water pump inlet.

8. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: In steps S2, S3, or S4, when the temperature of any heating membrane exceeds 60°C, the power relay pulse width (PWM) of the heating membrane is reduced via the fuel cell domain controller (FCU). The PWM amplitude is reduced by 6% at a rate that prevents overheating of the heating membrane if the temperature exceeds 2°C. If the heating membrane temperature is detected to be below 60°C again, the PWM amplitude is increased by 4% at a rate that ensures the heating membrane remains at a constant temperature of 60°C if the temperature is below 2°C. If the hydrogen temperature sensor T3 exceeds 30°C, the PTC heater is shut down, switching to the "full membrane heating" single mode. If the hydrogen temperature sensor T3 exceeds 45°C, the heating membrane stops working, switching to the fuel cell "stable self-heating" mode.

9. The control method for hydrogen heating in a vehicle fuel cell as described in claim 1, characterized in that: In step S6, if the fuel cell controller FCU detects that the ambient temperature exceeds 30°C, the above thermostats will increase their opening by 2%.

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