A vehicle fuel cell waste heat management system and method

Abstract

The present invention discloses a waste heat management system and method for a fuel cell used in a vehicle, which relates to the field of automotive technology. On the basis of satisfying the original functions, it uses special components such as heat exchange plates, three-way valves, and electronic water valves to form a low-cost combined heat and power supply system for vehicles. It uses the waste heat generated by the operation of the fuel cell system to coordinate and control the heating, cooling, and water heating of the fuel cell system in the vehicle. At the same time, the waste heat management system and various control strategies solve the problems of a sharp drop in the cooling medium temperature of the fuel cell system, poor power generation performance, and increased cooling load in the summer caused by the large temperature difference of the cooling medium on both sides of the heat exchange plate. Through the judgment strategy of the first temperature sensor and the second temperature sensor signal, the first water pump, the electronic fan of the fuel cell radiator, the electric heater, etc. are adjusted intelligently in real time, which can avoid temperature lag or advance control and reduce the energy consumption of the thermal management of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the field of automotive technology, and in particular to a vehicle fuel cell waste heat management system and method. Background Art

[0002] Fuel cells are highly efficient power generation systems that convert the chemical energy in fuel directly into electrical energy through an electrochemical reaction. This electrochemical reaction is a static power generation method that generates electricity without the need for physical motion and is not subject to the limitations of the Carnot cycle. Therefore, fuel cells offer advantages such as high efficiency, low noise, and zero pollution. This ensures their use in automobiles and their potential to become truly efficient and clean vehicles.

[0003] The operating temperature range of automotive fuel cells is 60-80℃, and the energy conversion efficiency is generally above 50%. The remaining energy is mainly dissipated outward in the form of heat, generating waste heat equivalent to the power generation. Currently, fuel cell vehicles have extremely low utilization rates of this waste heat, and basically use cooling media to directly remove excess heat to keep the internal temperature of the fuel cell stack relatively constant.

[0004] However, in winter, new energy vehicles typically use fuel heaters, electric heaters, electric fan heaters, and air conditioning systems to heat the cockpit and / or passenger compartment. These heating solutions all have significant drawbacks, including high procurement costs, difficulty in vehicle layout, and high winter energy consumption. They can also cause exhaust emissions and noise pollution. A fuel cell system for an automotive vehicle can generate continuous heat during normal operation, with the deionized cooling medium reaching a maximum temperature of 80°C. The heat generated depends on the fuel cell system's operating power, ambient temperature, and vehicle layout. This heat can meet the vehicle's passenger compartment heating needs, enabling the recycling of waste heat from the fuel cell system, improving energy efficiency, and reducing vehicle energy consumption. Summary of the Invention

[0005] The present invention provides a vehicle fuel cell waste heat management system and method to solve the above-mentioned problems existing in the prior art.

[0006] The present invention adopts the following technical solutions:

[0007] A vehicle fuel cell waste heat management system includes a cooling system and a water heating system. The cooling system includes a third water circulation loop, which includes a fuel cell system, a heat exchange plate, a fuel cell radiator and a first water pump connected end to end in sequence, and a first temperature sensor and a second temperature sensor are respectively provided at the water outlet and water inlet of the fuel cell system; the water heating system includes a water heating circulation loop, which includes a first electronic water valve, an electric heater, an in-vehicle radiator, a second water pump, a second electronic water valve and the heat exchange plate connected end to end in sequence.

[0008] Furthermore, the cooling system also includes a thermostat and an electronic three-way valve. In the third water circulation loop, the fuel cell radiator is connected to the heat exchange plate through the water inlet of the thermostat, the second water outlet of the thermostat, the water inlet of the electronic three-way valve, and the second water outlet of the electronic three-way valve; the water outlet one of the electronic three-way valve is connected to the first water pump, and the second water circulation loop of the cooling system is formed by the fuel cell system, thermostat, electronic three-way valve, fuel cell radiator and first water pump connected end to end in sequence; the first water outlet of the thermostat is connected to the first water pump, and the first water circulation loop of the cooling system is formed by the fuel cell system, thermostat and first water pump connected end to end in sequence.

[0009] A method for managing residual heat of a fuel cell for a vehicle uses the above-mentioned residual heat management system for a fuel cell for a vehicle, uses a first cooling medium in a cooling system, uses a second cooling medium in a water heating system, sets a signal of a first temperature sensor as a first temperature signal, sets a signal of a second temperature sensor as a second temperature signal, sets a threshold value T1, a threshold value T2, and a threshold value T3, and the method for managing residual heat of a fuel cell for a vehicle includes the following: (1) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (2) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (3) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (4) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (5) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (6) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (7) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (8) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to the first water outlet thereof, and the first cooling medium flows in the first water circulation loop; (9) when the first temperature signal is lower than the threshold value T1, the 2) When the first temperature signal reaches the threshold value T2 and the ambient temperature is higher than the threshold value T3, the water inlet of the thermostat is connected to its second water outlet, and the water inlet of the electronic three-way valve is connected to its first water outlet, so that the first cooling medium flows in the second water circulation system, while reducing the speed of the electronic fan of the fuel cell radiator and the first water pump; (3) When the first temperature signal reaches the threshold value T2 and the ambient temperature is lower than the threshold value T3, the water inlet of the thermostat is connected to its second water outlet, and the water inlet of the electronic three-way valve is connected to its second water outlet, so that the first cooling medium flows in the third water circulation loop system.

[0010] Furthermore, a control strategy for the fuel cell radiator is also included, which specifically includes the following steps: when the second temperature signal is lower than the threshold value T2, the electronic fan of the fuel cell radiator is turned off; when the second temperature signal is higher than the threshold value T2, the electronic fan is started, and the speed of the electronic fan increases as the second temperature signal rises and decreases as the second temperature signal drops.

[0011] Specifically, the second temperature signal is read every unit time period t1. If the difference in temperature drop before and after the second temperature signal within the unit time period t1 exceeds the set temperature difference ∆Th2, the speed ∆R of the electronic fan is increased within the unit time period t1 until the set maximum speed Rmax is reached. If the difference in temperature rise before and after the second temperature signal within the unit time period t1 is lower than the set temperature difference ∆Th2, the speed ∆R of the electronic fan is reduced within the unit time period t1 until the initial speed R0 is reached.

[0012] Furthermore, it also includes a control strategy for the first water pump, which specifically includes the following steps: when the first temperature signal is higher than the threshold value T1 and the second temperature signal is lower than the threshold value T2, the speed of the first water pump is the initial speed N1; when the second temperature signal is higher than the threshold value T2 and the temperature difference between the first temperature signal and the second temperature signal exceeds the set temperature difference ∆Th1, the speed of the first water pump ∆N is increased within the unit time period t2 until the maximum speed Nmax is reached; when the second temperature signal is lower than the threshold value T2, or the temperature difference between the first temperature signal and the second temperature signal is lower than the set temperature difference ∆Th1, the current speed of the first water pump is maintained unchanged; when the second temperature signal is lower than the threshold value T2, and the temperature difference between the second temperature signal and the first temperature signal is lower than ∆Th1, the speed of the first water pump ∆N is reduced within the unit time period t2 until the initial speed N1 is reached.

[0013] Furthermore, it also includes a control strategy for the electronic three-way valve, which specifically includes the following steps: when the first temperature signal is higher than the threshold value T2 and the ambient temperature is lower than the threshold value T3, the initial set opening between the water inlet and the second water outlet of the electronic three-way valve is W1; if the second temperature signal is higher than the threshold value T2, then the opening ∆W between the water inlet and the second water outlet of the electronic three-way valve is increased within every five unit time periods t1; if the second temperature signal is higher than (threshold value T2+a), where a is a temperature constant, then the opening ∆W between the water inlet and the second water outlet of the electronic three-way valve is reduced within every three unit time periods t1 until it is fully closed, the first cooling medium is switched to the second water circulation loop, and the heat exchange plate is short-circuited; if the second temperature signal is lower than the threshold value T2, the water inlet and the second water outlet of the electronic three-way valve are closed.

[0014] Furthermore, the system also includes a control strategy for the electric heater, specifically comprising the following steps: Three water inlet temperature thresholds are set: threshold T4, threshold T5, and threshold T6, with threshold T4 < threshold T5 < threshold T6. When the water inlet temperature falls below threshold T4, the heating power of the electric heater gradually increases. Specifically, the system operates at minimum heating power Pmin, and increases the heating power ∆P every unit time period t3 until it reaches the maximum heating power Pmax. When the water inlet temperature is greater than threshold T4 and less than threshold T5, the heating power of the electric heater remains unchanged. When the water inlet temperature is greater than threshold T5 and less than threshold T6, the heating power of the electric heater gradually decreases. Specifically, the heating power of the electric heater is reduced by ∆P at every time period t3 until the minimum heating power Pmin of the electric heater is reached. When the water inlet temperature of the electric heater is greater than the threshold value T6, the electric heater is turned off until the water inlet temperature of the electric heater is less than the threshold value T4 and the conditions for turning on the in-vehicle heating are met, and then the electric heater is turned on again to operate at the minimum heating power Pmin.

[0015] From the above description of the structure of the present invention, it can be seen that compared with the prior art, the present invention has the following advantages:

[0016] 1. This invention coordinates and controls the fuel cell system's heating, cooling, and in-vehicle water heating functions. An electronic three-way valve control strategy modulates the flow direction of the first cooling medium to meet the current heat requirements of each system. Based on signals from first and second temperature sensors, it intelligently adjusts the speed of the first water pump, the speed of the fuel cell radiator's electronic fan, and the power of the electric heater in real time. This prevents temperature lag or lead in control and reduces energy consumption for vehicle thermal management.

[0017] 2. During summer driving, the two electronic water valves in the water heating system are closed, effectively preventing the heat of the second coolant from being transferred to the passenger compartment heater vents through the heat exchange plate. This would result in a less effective air conditioning system in the passenger compartment and increased vehicle energy consumption. Furthermore, in the cooling system's first water circulation loop, the two electronic water valves can reduce heat loss in the water heating system, rapidly increasing the temperature of the first coolant in the cooling system's first water circulation loop and improving the power generation and efficiency of the fuel cell system.

[0018] 3. The waste heat management system transfers heat through heat exchange plates, rather than directly transferring the primary cooling medium to the cockpit and / or passenger compartment. This significantly reduces the primary cooling medium's requirements for the material and cleanliness of the cooling pipes flowing through the water heating system, as well as the insulation performance of the vehicle. This also reduces piping costs and the cost of the primary cooling medium.

[0019] 4. When a fuel cell vehicle is driven in winter, the heat generated by the fuel cell system is directed to the cockpit and / or passenger compartment for heating, reducing the energy consumed by the warm air in the vehicle in winter. At the same time, the electric heater is still retained to meet the real-time warm air needs of the entire vehicle, thereby achieving efficient energy saving of the vehicle.

[0020] 5. When a fuel cell vehicle is driven in the summer, the electronic three-way valve changes the flow direction of the first cooling medium, causing a short circuit in the heat exchange plate, consistent with a conventional fuel cell cooling system. This reduces the flow resistance of the cooling system and the speed of the first water pump, thereby improving the efficiency of the fuel cell radiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the waste heat management system in the present invention.

[0022] Figure 2 This is a flow chart of the waste heat management system control method in the present invention.

[0023] Figure 3 This is a flow chart of the first water pump control method in the present invention.

[0024] Figure 4 This is a flow chart of the electronic fan control method of the fuel cell system radiator in the present invention.

[0025] Figure 5 This is a flow chart of the electronic three-way valve control method in the present invention.

[0026] Figure 6 This is a flow chart of the warm air control method in the present invention. DETAILED DESCRIPTION

[0027] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, a vehicle fuel cell waste heat management system includes a cooling system and a water heating system. The cooling system includes a first water circulation loop, a second water circulation loop, and a third water circulation loop. The water heating system includes a water heating circulation loop.

[0029] like Figure 1 As shown, the first water circulation loop includes the fuel cell system, thermostat, electronic three-way valve, and first water pump, connected end-to-end via pipes. The water outlet of the fuel cell system is connected to the water inlet of the first water pump via the thermostat's water inlet w and first water outlet c. The thermostat, a conventional electronic or mechanical thermostat, can be installed at the fuel cell system's water outlet as well as its water inlet.

[0030] like Figure 1As shown, the second water circulation loop includes the fuel cell system, thermostat, electronic three-way valve, fuel cell radiator, and first water pump, connected end-to-end via pipes. The water outlet of the fuel cell system is connected to the fuel cell radiator via the thermostat's water inlet w, the thermostat's second water outlet d, the electronic three-way valve's water inlet p, and the electronic three-way valve's water outlet a.

[0031] like Figure 1 As shown, the third water circulation loop includes a fuel cell system, a thermostat, an electronic three-way valve, a heat exchange plate, a fuel cell radiator, and a first water pump, all connected end-to-end via pipes. The water outlet of the fuel cell system is connected to the heat exchange plate via the thermostat's water inlet w, the thermostat's second water outlet d, the electronic three-way valve's water inlet p, and finally the electronic three-way valve's second water outlet b.

[0032] like Figure 1 As shown, the water heating circuit includes a first electronic water valve, an electric heater, an in-car radiator, a second water pump, a second electronic water valve, and a heat exchanger plate, all connected end-to-end via pipes. Furthermore, a second expansion tank is connected to the water inlet of the second water pump. The electric heater can be eliminated, or replaced with a low-power PTC water heating solution that can meet the heating needs of the vehicle cabin.

[0033] like Figure 1 As shown, in addition, a first temperature sensor is provided at the water outlet of the fuel cell system, and a second temperature sensor is provided at the water inlet. A first expansion water tank is also connected to the water inlet of the first water pump.

[0034] like Figure 1 Specifically, the pipes are composed of silicone and stainless steel tubes. Technicians can select the appropriate pipe type based on the needs of different connection locations. For example, 316 or 316L stainless steel pipes can be used between long-distance components, while food-grade silicone pipes can be used at bends or between short-distance components.

[0035] like Figure 1 Specifically, a first cooling medium is used in the cooling system, and the dielectric conductivity of the first cooling medium is required to be no greater than 5uS / cm. A second cooling medium is used in the water heating system. The first water pump and the second water pump respectively apply lift and flow to the first cooling medium and the second cooling medium, forming a water flow within the water circulation loop and accelerating the circulation flow.

[0036] like Figures 1 to 6As shown, a method for managing residual heat in a vehicle fuel cell is described. Using the aforementioned residual heat management system for a vehicle fuel cell, the detection signal of a first temperature sensor is set as a first temperature signal, the detection signal of a second temperature sensor is set as a second temperature signal, and thresholds T1, T2, and T3 are set, with threshold T1 < threshold T2. For example, threshold T1 is 50°C, threshold T2 is 60°C, and threshold T3 is 20°C, but the values of thresholds T1, T2, and T3 are not limited to these.

[0037] like Figures 1 to 6 As shown, the vehicle fuel cell waste heat management method includes the following contents:

[0038] (1) When the first temperature signal is lower than threshold value T1, the water inlet w of the thermostat is connected to its first water outlet c, and the first cooling medium flows within the first water circulation loop, thereby short-circuiting the heat exchange plate and the fuel cell radiator, thereby rapidly increasing the temperature of the first cooling medium and improving the chemical reaction efficiency within the fuel cell system. At this time, the speed of the first water pump is speed N0.

[0039] (2) When the first temperature signal reaches threshold value T2 and the ambient temperature is higher than threshold value T3, the water inlet w of the thermostat is connected to its second water outlet d, and the water inlet p of the electronic three-way valve is connected to its first water outlet, so that the first cooling medium flows in the second water circulation system, thereby causing the heat exchange plate to be in a medium short circuit. This can reduce the flow resistance of the first cooling medium inside the heat exchange plate, quickly realize the first cooling medium to dissipate heat on the fuel cell radiator, and improve the heat dissipation efficiency of the first cooling medium. At the same time, the speed of the fuel cell radiator's electronic fan and the first water pump is reduced, thereby extending the vehicle's cruising range.

[0040] (3) When the first temperature signal reaches the threshold value T2 and the ambient temperature is lower than the threshold value T3, the water inlet w of the thermostat is connected to its second water outlet d, and the water inlet p of the electronic three-way valve is connected to its second water outlet b, so that the first cooling medium flows in the third water circulation loop system. At this time, the first cooling medium first dissipates heat through the heat exchange plate for the first time, and its heat can be transferred to the second cooling medium through the heat exchange plate, thereby providing the temperature of the second cooling medium; then the first cooling medium passes through the fuel cell radiator to achieve a second heat dissipation, which can avoid the second cooling medium requiring less heat than the first cooling medium, which affects the temperature of the first cooling medium being too high. In this process, under the premise of meeting the water inlet temperature requirements of the fuel cell system and utilizing the waste heat of the fuel cell system, the electronic fan of the fuel cell radiator can reduce the speed, and the electronic fan can even be set to the lowest speed to achieve energy-saving control.

[0041] like Figure 1 and Figure 3 As shown, (4) the control strategy of the first water pump specifically includes the following steps:

[0042] (4.1) When the first temperature signal is higher than the threshold value T1 and the second temperature signal is lower than the threshold value T2, the speed of the first water pump is the initial speed N1, and N0 <N1。

[0043] (4.2) When the second temperature signal is higher than the threshold value T2 and the temperature difference between the first temperature signal and the second temperature signal exceeds the set temperature difference ∆Th1, the speed of the first water pump is increased by ∆N within the unit time period t2 until the maximum speed Nmax is reached.

[0044] (4.3) When the second temperature signal is lower than the threshold value T2, or the temperature difference between the first temperature signal and the second temperature signal is lower than the set temperature difference ∆Th1, the current speed of the first water pump is maintained unchanged.

[0045] (4.4) When the second temperature signal is lower than the threshold value T2 and the temperature difference between the second temperature signal and the first temperature signal is lower than ∆Th1, the speed of the first water pump is reduced by ∆N within the unit time period t2 until it reaches the initial speed N1.

[0046] like Figure 1 and Figure 4 As shown, (5) also includes a control strategy for the fuel cell radiator, which specifically includes the following steps:

[0047] (5.1) When the second temperature signal is lower than the threshold value T2, the electronic fan of the fuel cell radiator is turned off, and the electronic fan PWM is set to 0.

[0048] (5.2) When the second temperature signal is higher than the threshold value T2, the electronic fan is started, and the speed of the electronic fan increases as the second temperature signal increases and decreases as the second temperature signal decreases, as follows;

[0049] (5.2.1) Read the second temperature signal at every unit time period t1; if the difference in temperature drop between the second temperature signal before and after the second temperature signal within the unit time period t1 exceeds a predetermined temperature difference ∆Th2, increase the speed ∆R of the electronic fan during the unit time period t1 until the speed reaches a predetermined maximum speed Rmax.

[0050] (5.2.2) Read the second temperature signal every unit time period t1; if the front and rear temperatures of the second temperature signal within the unit time period t1 are 0, maintain the current speed of the electronic fan unchanged.

[0051] (5.2.3) Read the second temperature signal at every unit time period t1; if the difference in temperature rise between the second temperature signal before and after the unit time period t1 is less than the set temperature difference ∆Th2, then reduce the speed ∆R of the electronic fan within the unit time period t1 until it reaches the initial speed R0.

[0052] like Figure 5 As shown, (6) the control strategy of the electronic three-way valve specifically includes the following steps:

[0053] (6.1) When the first temperature signal is higher than the threshold value T2 and the ambient temperature is lower than the threshold value T3, the initial setting opening between the water inlet p and the water outlet b of the electronic three-way valve is W1.

[0054] (6.2) When the second temperature signal is higher than the threshold value T2, the opening ∆W between the water inlet p and the water outlet b of the electronic three-way valve is increased in every five unit time periods t1.

[0055] (6.3) When the second temperature signal exceeds (threshold T2 + a), the opening ∆W between the water inlet p and the water outlet b of the electronic three-way valve is reduced within every three unit time periods t1 until it is fully closed, switching the first cooling medium to the second water circulation loop and short-circuiting the heat exchange plate. Where a is a temperature parameter, and values of a include, but are not limited to, 10°C.

[0056] (6.4) When the second temperature signal falls below threshold value T2, the water inlet and outlet 2 of the electronic three-way valve are closed. This prevents the passenger compartment temperature from being too low, leading to inefficient heat transfer in the heat exchange plate, causing a rapid drop in the temperature of the first coolant, thereby lowering the operating temperature of the fuel cell system and affecting the power output performance of the fuel cell.

[0057] like Figure 1 and Figure 6 As shown, (7) the control of the water heating system also includes the following:

[0058] When the driver's control signal to turn on the heater is received, the first electronic water valve, the second electronic water valve, the second water pump and the radiator in the vehicle are all turned on. On the premise of meeting the water inlet temperature requirements of the fuel cell system and utilizing the waste heat of the fuel cell system, the electronic fan on the fuel cell radiator can reduce its speed.

[0059] When a control signal is received to turn off the heating or the system is powered off, the electric heater stops working and the second water pump stops working after a delay of t; and after the water pump stops working, the first electronic water valve and the second electronic water valve are closed at the same time.

[0060] When the ambient temperature is low, the electric heating of the water heating circulation loop generates heat, which is transferred to the third water circulation loop through the circulation of the second cooling medium and the transfer of the heat exchange plate, thereby achieving thermal insulation of the fuel cell system.

[0061] like Figure 1 and Figure 6 As shown in FIG, the control strategy of the electric heater in the water heating system specifically includes the following steps:

[0062] Three water heater inlet temperature thresholds are set: threshold T4, threshold T5, and threshold T6, with threshold T4 < threshold T5 < threshold T6. For example, threshold T4 is 45°C, threshold T5 is 55°C, and threshold T6 is 60°C. However, the values of thresholds T4, T5, and T6 are not limited to these.

[0063] (7.1) When the water inlet temperature of the electric heater is less than a threshold value T4, the heating power of the electric heater gradually increases; specifically, the electric heater operates at a minimum heating power Pmin, and the heating power of the electric heater is increased by ∆P every unit time period t3 until the maximum heating power of the electric heater is reached Pmax.

[0064] (7.2) When the water inlet temperature of the electric heater is greater than the threshold value T4, the heating power of the electric heater remains unchanged.

[0065] (7.3) When the water temperature entering the electric heater is greater than a threshold value T5, the heating power of the electric heater gradually decreases; specifically, the heating power of the electric heater decreases by ∆P at every time period t3 until the minimum heating power Pmin of the electric heater is reached.

[0066] (8.4) When the water temperature entering the electric heater is greater than the threshold value T6, the electric heater is turned off. After the water temperature entering the electric heater is less than the threshold value T4 and the conditions for turning on the vehicle heating are met, the electric heater is turned on again so that the electric heater operates at the minimum heating power Pmin.

[0067] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A method for managing waste heat of a fuel cell for a vehicle, characterized by: The vehicle fuel cell waste heat management system adopted includes a cooling system and a water heating system. The cooling system includes a third water circulation loop, and the third water circulation loop includes a fuel cell system, a heat exchange plate, a fuel cell radiator and a first water pump connected end to end in sequence, and a first temperature sensor and a second temperature sensor are respectively provided at the water outlet and water inlet of the fuel cell system; the water heating system includes a water heating circulation loop, which includes a first electronic water valve, an electric heater, an in-vehicle radiator, a second water pump, a second electronic water valve and the heat exchange plate connected end to end in sequence; after the second water pump stops working, the first electronic water valve and the second electronic water valve are closed at the same time; the cooling system includes a third water circulation loop, and the third water circulation loop includes a fuel cell system, a heat exchange plate, a fuel cell radiator and a first water pump connected end to end in sequence, and a first temperature sensor and a second temperature sensor are respectively provided at the water outlet and water inlet of the fuel cell system; the water heating system includes a water heating circulation loop, which includes a first electronic water valve, an electric heater, an in-vehicle radiator, a second water pump, a second electronic water valve and the heat exchange plate connected end to end in sequence; after the second water pump stops working, the first electronic water valve and the second electronic water valve are closed at the same time; The system also includes a thermostat and an electronic three-way valve. In the third water circulation loop, the fuel cell radiator is connected to the heat exchange plate via the water inlet of the thermostat, the second water outlet of the thermostat, the water inlet of the electronic three-way valve, and the second water outlet of the electronic three-way valve; the first water outlet of the electronic three-way valve is connected to the first water pump, and the fuel cell system, thermostat, electronic three-way valve, fuel cell radiator, and first water pump connected end to end in sequence constitute the second water circulation loop of the cooling system; the first water outlet of the thermostat is connected to the first water pump, and the fuel cell system, thermostat, and first water pump connected end to end in sequence constitute the first water circulation loop of the cooling system; A first cooling medium is used in the cooling system, a second cooling medium is used in the water heating system, a signal from the first temperature sensor is set to a first temperature signal, and a signal from the second temperature sensor is set to a second temperature signal. The vehicle fuel cell waste heat management method includes the following: The control strategy for the electric heater specifically includes the following steps: setting three points as threshold values for the water inlet temperature of the electric heater, namely threshold value T4, threshold value T5 and threshold value T6, and threshold value T4 < threshold value T5 < threshold value T6; when the water inlet temperature of the electric heater is less than threshold value T4, the heating power of the electric heater gradually increases; when the water inlet temperature of the electric heater is greater than threshold value T4, the heating power of the electric heater remains unchanged at the current power; when the water inlet temperature of the electric heater is greater than threshold value T5, the heating power of the electric heater gradually decreases; when the water inlet temperature of the electric heater is greater than threshold value T6, the electric heater is turned off until the water inlet temperature of the electric heater is less than threshold value T4 and the conditions for turning on the heating in the vehicle are met, and then the electric heater is turned on again; Threshold values T1, T2, and T3 are set, and the vehicle fuel cell waste heat management method further includes the following: (1) when the first temperature signal is lower than the threshold value T1, the water inlet of the thermostat is connected to its first water outlet, and the first cooling medium flows in the first water circulation loop; (2) when the first temperature signal reaches the threshold value T2 and the ambient temperature is higher than the threshold value T3, the water inlet of the thermostat is connected to its second water outlet, and the water inlet of the electronic three-way valve is connected to its first water outlet, so that the first cooling medium flows in the second water circulation system and the heat exchange plate is in a medium short circuit; (3) when the first temperature signal reaches the threshold value T2 and the ambient temperature is lower than the threshold value T3, the water inlet of the thermostat is connected to its second water outlet, and the water inlet of the electronic three-way valve is connected to its second water outlet, so that the first cooling medium flows in the third water circulation loop system; It also includes a control strategy for the electronic three-way valve, which specifically includes the following steps: when the first temperature signal is higher than the threshold value T2 and the ambient temperature is lower than the threshold value T3, the initial set opening between the water inlet and the second water outlet of the electronic three-way valve is W1; if the second temperature signal is higher than the threshold value T2, then the opening ∆W between the water inlet and the second water outlet of the electronic three-way valve is increased within every five unit time periods t1; if the second temperature signal is higher than the threshold value T2+a, where a is a temperature constant, then the opening ∆W between the water inlet and the second water outlet of the electronic three-way valve is reduced within every three unit time periods t1 until it is fully closed, the first cooling medium is switched to the second water circulation loop, and the heat exchange plate is short-circuited; if the second temperature signal is lower than the threshold value T2, the water inlet and the second water outlet of the electronic three-way valve are closed.

2. A method for managing waste heat of a fuel cell for a vehicle according to claim 1, characterized in that: It also includes a control strategy for the water heating system: when a control signal to turn on the heater is received, the first electronic water valve, the second electronic water valve, the second water pump and the radiator in the vehicle are all turned on; when a control signal to turn off the heater or the system is powered off is received, the electric heater stops working and the second water pump stops working after a delay of t; after the water pump stops working, the first electronic water valve and the second electronic water valve are closed at the same time; when the ambient temperature is low, heat is generated by electric heating of the water heating circulation loop, and the heat is transferred to the third water circulation loop through the circulation of the second cooling medium and the transfer of the heat exchange plate, thereby achieving thermal insulation of the fuel cell system.

3. The method for managing waste heat of a fuel cell for a vehicle according to claim 1, wherein: It also includes a control strategy for the fuel cell radiator, which specifically includes the following steps: when the second temperature signal is lower than the threshold value T2, the electronic fan of the fuel cell radiator is turned off; when the second temperature signal is higher than the threshold value T2, the electronic fan is started, and the speed of the electronic fan increases as the second temperature signal rises and decreases as the second temperature signal drops.

4. The method for managing waste heat of a fuel cell for a vehicle according to claim 1, characterized in that: The control strategy of the first water pump is also included, which specifically includes the following steps: when the first temperature signal is higher than the threshold value T1 and the second temperature signal is lower than the threshold value T2, the speed of the first water pump is the initial speed N1; when the second temperature signal is higher than the threshold value T2, and the temperature difference between the first temperature signal and the second temperature signal exceeds the set temperature difference Th1, then increase the speed of the first water pump within the unit time period t2 N, until the maximum speed Nmax is reached; when the second temperature signal is lower than the threshold T2, or the temperature difference between the first temperature signal and the second temperature signal is lower than the set temperature difference When the second temperature signal is lower than the threshold value T2, and the temperature difference between the second temperature signal and the first temperature signal is lower than Th1, then in the unit time period t2, reduce the speed of the first water pump N, until the initial speed N1 is reached.

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