A hydrogen fuel cell thermal management system suitable for low temperature environments

Abstract

The application discloses a hydrogen fuel cell thermal management system suitable for low-temperature environment and belongs to the technical field of vehicle thermal energy management of hydrogen fuel cells, and comprises a heater, a first interface connected with a water pump first interface, a first three-way valve, a first interface connected with the heater second interface and a second interface connected with the water pump first interface, a third three-way valve, a second interface connected with the heater second interface, a radiator, a hydrogen fuel cell stack, an air compressor, a second interface being an air side, an intercooler, a first interface connected with the first three-way valve second interface and a third interface connected with the hydrogen fuel cell stack second interface, a second three-way valve, a first interface connected with the intercooler third interface and a second interface connected with the air compressor fourth interface, a heat exchange pipe arranged in a driver seat and a water storage tank, a first interface connected with the heat exchange pipe fourth interface. The application can utilize waste heat to heat the driver, keep the battery warm and humidify the environment through recycling water in tail gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle thermal energy management of hydrogen fuel cells, and particularly relates to a hydrogen fuel cell thermal management system suitable for low-temperature environments. BACKGROUND

[0002] The forklift for low-temperature environments is a special material handling equipment that is required to work normally in a temperature range of-30 DEG C to +5 DEG C.

[0003] At present, the more commonly used forklifts are mainly of the internal combustion engine type and the pure electric type. The internal combustion engine type is not suitable for agricultural products, biological medicines and other scenes because of the emission, the requirement of ventilation for the environment, and the large engine noise and high pollution. The power battery in the pure electric type is greatly affected by temperature, and the battery discharge capacity and capacity greatly decrease at low temperature, which affects the vehicle endurance and operation efficiency. In addition, the forklift needs to be operated frequently in the low-temperature environment for a long time, and most of the vehicles do not have heating equipment, so the driver's operation environment is poor. A large amount of waste heat is generated in the operation process of the hydrogen fuel cell system, accounting for about 50%-60% of the total consumed energy. At present, the waste heat is dissipated in the form of heat exchange and tail exhaust water vapor, and the comprehensive energy utilization rate is low. In addition, in the low-temperature environment, the main methods for humidification in cold storage are the anti-freezing high-pressure micro-fog system and the hot steam diffusion humidification system, and the cost of humidification in the ultra-low-temperature environment and local humidification is high. SUMMARY

[0004] To solve the above-mentioned problems in the prior art, the present application provides a hydrogen fuel cell thermal management system suitable for low-temperature environments, which uses waste heat to heat the driver, to keep the battery warm, and to humidify the environment by recovering water from the exhaust gas, and has the advantages of energy saving, environmental protection, reliability and low cost.

[0005] The technical scheme of the present application is as follows:

[0006] A hydrogen fuel cell thermal management system suitable for low-temperature environments is provided, which comprises:

[0007] A heater, a first interface of the heater being connected to a first interface of a water pump through a pipeline;

[0008] A first three-way valve, a first interface of the first three-way valve being connected to a second interface of the heater through a pipeline, and a second interface of the first three-way valve being connected to the pipeline between the first interface of the water pump and the first interface of the heater;

[0009] A third three-way valve, a second interface of the third three-way valve being connected to the pipeline between the heater and the first interface of the first three-way valve;

[0010] A radiator is arranged at the position of the driver seat leg cover, one end of the radiator is connected to the first interface of the third three-way valve through a pipe, and the pipe connecting the radiator and the first interface of the third three-way valve passes through the power battery, so that the power battery is cooled and the cooled heat is used to heat the driver seat leg, and the other end of the radiator is connected to the second interface of the water pump;

[0011] A hydrogen fuel cell stack, a first interface of the hydrogen fuel cell stack is connected to the third interface of the first three-way valve through a pipe;

[0012] An air compressor, a first interface of the air compressor is connected to the pipe of the second interface of the first three-way valve, and a second interface of the air compressor is an air side for inputting external air;

[0013] A intercooler, a first interface of the intercooler is connected to the pipe of the second interface of the first three-way valve, a second interface of the intercooler is connected to the pipe between the third interface of the air compressor and the second interface of the third three-way valve, and a fourth interface of the intercooler is connected to the second interface of the hydrogen fuel cell stack;

[0014] A second three-way valve, a first interface of the second three-way valve is connected to the third interface of the intercooler, and a second interface of the second three-way valve is connected to the fourth interface of the air compressor;

[0015] A heat exchange pipe, the heat exchange pipe is arranged inside the driver seat, a first interface of the heat exchange pipe is connected to the third interface of the third three-way valve, and a second interface of the heat exchange pipe is connected to the pipe between the first interface of the third three-way valve and the radiator;

[0016] A water storage tank, a first interface of the water storage tank is connected to the fourth interface of the heat exchange pipe.

[0017] Further, in the hydrogen fuel cell thermal management system suitable for low temperature environment, a back pressure regulating valve is further included, a first interface of the back pressure regulating valve is connected to the third interface of the hydrogen fuel cell stack, and a second interface of the back pressure regulating valve is connected to the third interface of the heat exchange pipe.

[0018] Further, in the hydrogen fuel cell thermal management system suitable for low temperature environment, a fourth three-way valve is further included, a first interface of the fourth three-way valve is connected to the pipe between the second interface of the back pressure regulating valve and the third interface of the heat exchange pipe, a second interface of the fourth three-way valve is connected to the third interface of the second three-way valve, and a third interface of the fourth three-way valve is connected to the second interface of the water storage tank.

[0019] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a cut-off valve is further included, a first interface of the cut-off valve is connected to the third interface of the air compressor, and a second interface of the cut-off valve is connected to the pipeline between the second interface of the third three-way valve and the fourth interface of the hydrogen fuel cell stack.

[0020] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a fifth temperature detecting device is arranged on the pipeline between the first three-way valve and the hydrogen fuel cell stack, the fourth interface of the hydrogen fuel cell stack is connected to the pipeline between the second interface of the cut-off valve and the second interface of the third three-way valve through a pipeline, and a first temperature detecting device is arranged on the pipeline of the fourth interface of the hydrogen fuel cell stack.

[0021] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a second temperature detecting device is arranged on the heat exchange pipe.

[0022] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a third temperature detecting device is arranged on the pipeline between the third three-way valve and the power battery.

[0023] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a fourth temperature detecting device is arranged between the radiator and the leg cover of the driver seat.

[0024] Further, in the hydrogen fuel cell thermal management system for low temperature environment, a nebulizer is further included, and the nebulizer is connected to the third interface of the water storage tank.

[0025] Further, in the hydrogen fuel cell thermal management system for low temperature environment, the heater includes a PTC heater.

[0026] The main advantages of the technical scheme of the present application are as follows:

[0027] The application discloses a hydrogen fuel cell thermal management system suitable for a low-temperature environment. BRIEF DESCRIPTION OF DRAWINGS

[0028] The drawings described herein are used to provide further understanding of the embodiments of the application, and form a part of the application. The schematic embodiments of the application and the description thereof are used to explain the application, and do not constitute improper limitation on the application. In the drawings:

[0029] Figure 1 A structure schematic diagram of a hydrogen fuel cell thermal management system suitable for a low-temperature environment is provided for an embodiment of the application.

[0030] Label explanation:

[0031] 1, heater; 2, water pump; 3, fan; 4, radiator; 5, hydrogen fuel cell stack; 6, air compressor; 7, intercooler; 8, power battery; 9, heat exchange pipe; 10, water storage tank; 11, atomizer;

[0032] V1, first three-way valve; V2, second three-way valve; V3, third three-way valve; V4, fourth three-way valve; V5, back pressure regulating valve; V6, stop valve;

[0033] T1, first temperature detection device; T2, second temperature detection device; T3, third temperature detection device; T4, fourth temperature detection device; T5, fifth temperature detection device. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] The following is in conjunction with the appendix Figure 1 The technical solutions provided in the embodiments of the present invention will be described in detail.

[0036] As attached Figure 1 As shown, in Figure 1 In the diagram, the solid line represents the coolant circuit, the dashed line represents the air circuit, and the arrows indicate the flow direction of the coolant or air.

[0037] Specifically, this embodiment of the invention provides a thermal management system for hydrogen fuel cells suitable for low-temperature environments. The system includes: a heater 1, a first three-way valve V1, a third three-way valve V3, a radiator 4, a hydrogen fuel cell stack 5, an air compressor 6, an intercooler 7, a second three-way valve V2, heat exchange tubes 9, and a water storage tank 10, wherein:

[0038] The first interface of the heater 1 is connected to the first interface of the water pump 2 through a pipeline; the first interface of the first three-way valve V1 is connected to the second interface of the heater 1 through a pipeline, and the second interface of the first three-way valve V1 is connected to the pipeline between the first interface of the water pump 2 and the first interface of the heater 1; the second interface of the third three-way valve V3 is connected to the pipeline between the heater 1 and the first interface of the first three-way valve V1; the radiator 4 is arranged at the leg cover position of the driver seat, one end of the radiator 4 is connected to the first interface of the third three-way valve V3 through a pipeline, and the pipeline connecting the radiator 4 and the first interface of the third three-way valve V3 passes through the power battery 8, so that the power battery 8 is cooled and the heat generated by the cooling is used to heat the driver seat leg; the other end of the radiator 4 is connected to the second interface of the water pump 2; the first interface of the hydrogen fuel cell stack 5 is connected to the third interface of the first three-way valve V1 through a pipeline; the first interface of the air compressor 6 is connected to the pipeline of the second interface of the first three-way valve V1, and the second interface of the air compressor 6 is an air side for inputting external air; the first interface of the intercooler 7 is connected to the pipeline of the second interface of the first three-way valve V1, the second interface of the intercooler 7 is connected to the pipeline between the third interface of the air compressor 6 and the second interface of the third three-way valve V3, the fourth interface of the intercooler 7 is connected to the second interface of the hydrogen fuel cell stack 5; the first interface of the second three-way valve V2 is connected to the third interface of the intercooler 7, and the second interface of the second three-way valve V2 is connected to the fourth interface of the air compressor 6; the heat exchange pipe 9 is arranged inside the driver seat, the first interface of the heat exchange pipe 9 is connected to the third interface of the third three-way valve V3, and the second interface of the heat exchange pipe 9 is connected to the pipeline between the first interface of the third three-way valve V3 and the radiator 4; the first interface of the water storage tank 10 is connected to the fourth interface of the heat exchange pipe 9.

[0039] Specifically, the hydrogen fuel cell stack 5 is a device for directly converting the chemical energy of hydrogen fuel into electrical energy, also known as an electrochemical generator. It is the core part of the hydrogen fuel cell power system, and the electrical energy output is generated through an electrochemical reaction. The stack is the place where the electrochemical reaction occurs, and is also the core part of the hydrogen fuel cell power system; it is composed of multiple single cells in a stacked and combined manner. The bipolar plate and the membrane electrode are alternately stacked, the sealing element is embedded between each single cell, and after being compressed by the front and rear end plates, it is fastened and fixed by a screw, thereby forming the hydrogen fuel cell stack 5.

[0040] In some optional implementations of the embodiment, the heater 1 is preferably a PTC (positive temperature coefficient) heater, and the heat exchange pipe 9 is preferably a metal heat exchange pipe 9. In the embodiment of the application, the heat exchange pipe 9 has independent cooling liquid side channels and air side channels to realize cooling liquid exchange and steam exchange, for example, tail exhaust heat and heat exchange generated by the heat exchange pipe 9, so that the heat exchange pipe 9 of the embodiment of the application has a double heat exchange function.

[0041] Specifically, in the hydrogen fuel cell thermal management system suitable for low-temperature environment in the embodiment of the present application, a back pressure regulating valve V5 is further included, a first interface of the back pressure regulating valve V5 is connected to a third interface of the hydrogen fuel cell stack 5, and a second interface of the back pressure regulating valve V5 is connected to a third interface of the heat exchange pipe 9.

[0042] In this way, when the hydrogen fuel cell stack 5 is running, the tail gas (containing a large amount of waste heat and water vapor) is introduced into the heat exchange pipe 9 (air side channel) inside the seat through the regulation of the back pressure regulating valve V5. During the flow of the tail gas in the heat exchange pipe 9, the waste heat carried by the tail gas is transferred to the heat exchange pipe 9 through heat conduction, thereby heating the driver's seat. At the same time, the back pressure regulating valve V5 can also regulate the pressure and flow of the tail gas, ensure that the hydrogen fuel cell stack 5 works in a stable back pressure environment, and control the amount of tail gas entering the heat exchange pipe 9 to adapt to different heating needs. After the waste heat is released by the tail gas through the heat exchange pipe 9, the water vapor in the tail gas condenses and enters the water storage tank 10, thereby providing a water source for the subsequent local humidification function of the atomizer 11.

[0043] Therefore, by adding the back pressure regulating valve V5, a closed loop of "tail exhaust waste heat recovery-seat heating-water vapor utilization" is constructed in the embodiment of the present application, which not only solves the problem of waste of hydrogen fuel cell waste heat, but also improves the driving comfort and scene adaptability (such as clean scene, cold storage humidification) of the forklift in low-temperature environment. Specifically, the tail exhaust waste heat is introduced into the heat exchange pipe 9 through the back pressure regulating valve V5 and is directly used for seat heating, so that the originally wasted waste heat is reused, thereby significantly improving the energy comprehensive utilization rate of the system. The tail exhaust waste heat heats the seat through the heat exchange pipe 9, and the radiator 4 heats the legs, thereby forming double heating of "seat + legs", which effectively improves the driving comfort in the environment of-30℃ to +5℃. The back pressure regulating valve V5 guides the tail gas to release waste heat through the heat exchange pipe 9 and then enters the water storage tank 10, so that the water vapor is more easily condensed and recovered, thereby providing a low-cost water source for the atomizer 11, avoiding the high energy consumption of the traditional anti-freezing high-pressure micro-fog or hot steam system, and being especially suitable for local humidification demand in cold storage and other scenes. In addition, the back pressure regulating valve V5 stabilizes the working state of the hydrogen fuel cell stack 5 by regulating the tail exhaust pressure, thereby avoiding the influence of tail pressure fluctuation on the output efficiency of the stack, and cooperating with the coordinated control of the first three-way valve V1 and the third three-way valve V3, so that the thermal management system is more reliable in low-temperature environment.

[0044] Specifically, the hydrogen fuel cell thermal management system suitable for low-temperature environment provided by the embodiment of the present application further includes a fourth three-way valve V4, a first interface of the fourth three-way valve V4 is connected to a pipeline between the second interface of the back pressure regulating valve V5 and the third interface of the heat exchange pipe 9, a second interface of the fourth three-way valve V4 is connected to a third interface of the second three-way valve V2, and a third interface of the fourth three-way valve V4 is connected to a second interface of the water storage tank 10.

[0045] Thus, in the embodiment of the present application, the fourth three-way valve V4 realizes the regulation of the flow direction of two kinds of gas by interface switching. Specifically, when the seat heating needs to be strengthened, the first interface of the fourth three-way valve V4 is in communication with the second interface, so that the tail gas output by the back pressure regulating valve V5 and the pressurized air output by the second three-way valve V2 flow together and enter the heat exchange pipe 9 (air side channel). At this time, the gas after flowing together carries more residual heat (tail exhaust residual heat + pressurized air residual heat), which is used for heating the seat through the heat exchange pipe 9. When there is no need for additional heating or the water vapor recovery needs to be prioritized, the first interface of the fourth three-way valve V4 is in communication with the third interface, and the tail gas (or the gas after flowing together) directly enters the water storage tank 10, so as to ensure that the water vapor condensation recovery function is not affected.

[0046] In some optional implementations, the switching of the fourth three-way valve V4 is triggered by the controller according to the temperature value detected by the temperature detection device.

[0047] Therefore, the fourth three-way valve V4 realizes the synergistic use of "pressurized air residual heat + tail exhaust residual heat" through gas path switching, which not only strengthens the heating capacity in a low temperature environment, but also guarantees the continuity of the water vapor recovery and humidification function.

[0048] Specifically, by flowing the pressurized air (containing the heat dissipation residual heat of the air compressor 6) and the tail gas (containing the stack residual heat) together into the heat exchange pipe 9, the total amount of heat entering the heating circuit is increased, solving the problem of possible insufficient heating by single tail exhaust residual heat. Especially in an ultra-low temperature environment such as-30℃, the seat temperature can be raised faster to improve the driver's operating environment. Based on the path switching of the fourth three-way valve V4, the hydrogen fuel cell thermal management system suitable for a low temperature environment provided in the embodiment of the present application can dynamically adjust the heating intensity according to the real-time temperature demand. For example, when the low temperature heating demand is high, the pressurized air and the tail gas are flowed together to maximize the residual heat utilization. After the temperature meets the standard, the flow-together path is closed, and only the tail gas or the water vapor is directly recovered to avoid energy waste. The temperature management method provided in the embodiment of the present application enables the vehicle to adapt to different working conditions in a wide temperature range of-30℃ to +5℃, and no matter whether the flow-together heating is enabled, the fourth three-way valve V4 can finally guide the gas into the water storage tank 10 to ensure the stable recovery of the tail exhaust water vapor, providing a continuous water source for the local humidification of the atomizer 11, reducing the low temperature environment, and in addition, in the embodiment of the present application, the fourth three-way valve V4 also cooperates with other valves such as the first three-way valve V1, the second three-way valve V2 and the third three-way valve V3, and the temperature detection device, so that the controller can more accurately regulate the heat input of the heating circuit, avoiding overheating or insufficient heating, and improving the operation stability of the hydrogen fuel cell system in a low temperature environment.

[0049] Specifically, in the hydrogen fuel cell thermal management system for low-temperature environment, a stop valve V6 is further included, a first interface of the stop valve V6 is connected to the third interface of the air compressor 6, and a second interface of the stop valve V6 is connected to a pipeline of the second interface of the third three-way valve V3.

[0050] In this way, the stop valve V6 is arranged based on the differentiated requirements in the system starting and running stages, including: passage blocking in the hydrogen fuel cell starting stage, passage opening in the running stage, and cooperative control with other components, wherein:

[0051] The passage blocking in the starting stage includes: the cooling liquid needs to be preheated by the heater 1 before the hydrogen fuel cell starts, at this time, the stop valve V6 is closed to block the passage between the air compressor 6 and the third three-way valve V3, so as to ensure that the output heat is concentrated to flow to the stack and the power battery 8 (passage switching through the first three-way valve V1), and avoid the heat from being dispersed to the heating circuit (such as the seat heat exchange pipe 9 and the radiator 4), so as to quickly raise the stack inlet temperature and the power battery 8 inlet temperature, and meet the low-temperature starting condition.

[0052] The passage opening in the running stage includes: after the stack starts, the stop valve V6 is opened, so that the gas / cooling liquid (carrying the waste heat generated by the operation of the air compressor 6) output by the air compressor 6 enters the heating circuit where the third three-way valve V3 is located. At this time, the waste heat of the air compressor 6 cooperates with the stack heat dissipation and the intercooler 7 heat dissipation, and heats the seat through the heat exchange pipe 9 and heats the leg air through the radiator 4.

[0053] The cooperative control with other components includes: the opening and closing states of the stop valve V6 are determined by the controller according to the feedback of the temperature detection device, and are synchronously linked with the passage switching of the three-way valves such as the first three-way valve V1 and the third three-way valve V3, so as to ensure that the energy distribution is optimal in the whole process of “starting-preheating-running-heating” of the system.

[0054] Therefore, by closing the stop valve V6 in the starting stage, the heat of the heater 1 can be prevented from being dispersed to the heating circuit (seat, leg), so that the heat is concentrated for preheating of the power battery 8 and the stack, and the problems of slow starting and starting failure in a low-temperature environment are solved. Through the stop valve V6, the technical effect of “normal starting of the hydrogen fuel cell after the inlet temperature of the hydrogen fuel cell stack 5 and the inlet temperature of the power battery 8 reach the coolant set temperature” is realized. By opening the stop valve V6 in the running stage, the waste heat of the air compressor 6 is connected to the heating circuit, and the waste heat of the stack and the intercooler 7 is utilized cooperatively, so that the total amount of recoverable waste heat is increased. The technical problem of low utilization rate of waste heat of the hydrogen fuel cell system in the prior art is solved, the waste heat of the air compressor 6 that would be dissipated is converted into energy for heating of the driving environment, and the energy comprehensive utilization rate of the system is further improved. Through the on-off control of the stop valve V6, the mode switching of “concentrated preheating in the starting stage” and “dispersed heating in the running stage” is realized, and the invalid consumption of energy is avoided. For example, energy is not wasted for heating of the seat in the starting stage, and the waste heat is fully utilized in the running stage, so that no additional hydrogen energy or electric energy is consumed, and the endurance of the hydrogen fuel cell forklift is indirectly improved. At the same time, through the linkage of the on-off state of the stop valve V6 with the temperature detection device and the controller, the management system can adapt to the dynamic changes such as sudden drop of the environmental temperature, prolong the closing time of the stop valve V6 in the starting stage to strengthen the preheating, and open the stop valve V6 in advance to utilize the waste heat when the environmental temperature is high, so that the working stability of the forklift and the like in a wide temperature range of -30°C to +5°C is improved.

[0055] In summary, the stop valve V6 realizes the precise distribution of system energy in the “preheating” and “heating” links in the manner of “blocking in the starting stage and conducting in the running stage”, which not only guarantees the reliability of low-temperature starting, but also improves the waste heat utilization efficiency in the running stage, and is an important guarantee for “stable starting + efficient operation” of the hydrogen fuel cell forklift in a low-temperature environment.

[0056] Specifically, in the hydrogen fuel cell thermal management system suitable for a low-temperature environment in the embodiment of the present application, the fifth temperature detection device T5 is arranged on the pipeline between the first three-way valve V1 and the hydrogen fuel cell stack 5, the fourth interface of the hydrogen fuel cell stack 5 is connected to the pipeline between the second interface of the stop valve V6 and the second interface of the third three-way valve V3, and the first temperature detection device T1 is arranged on the pipeline of the fourth interface of the hydrogen fuel cell stack 5.

[0057] In this way, by installing the fifth temperature detection device T5 on the pipeline between the first three-way valve V1 and the hydrogen fuel cell stack 5 inlet, the temperature of the cooling liquid entering the stack can be detected in real time, so that in the starting stage, the controller determines whether the hydrogen fuel cell stack 5 inlet temperature reaches the starting threshold value through the feedback of the fifth temperature detection device T5, if the threshold value is not reached, the controller controls the heater 1 to work continuously, and the stop valve V6 is closed, to ensure that the cooling liquid concentrates to preheat the hydrogen fuel cell stack 5, until the fifth temperature detection device T5 reaches the set value, to ensure the stable start of the stack in the environment of-30℃ to +5℃.

[0058] By installing the first temperature sensor on the pipeline between the stack outlet and the third three-way valve V3, the temperature of the outlet cooling liquid when the stack is running is detected. When the first temperature detection device T1 reaches the set value, the controller triggers the third three-way valve V3 to switch the path, so that the high-temperature cooling liquid at the stack outlet flows into the seat heat exchange pipe 9 and the radiator 4, to start the seat heating and leg heating functions; if the first temperature detection device T1 does not reach the set value, the cooling liquid is maintained in the stack internal circulation, to avoid energy waste caused by opening the heating loop when the waste heat is not fully utilized.

[0059] In addition, the first temperature detection device T1 and the fifth temperature detection device T5 of the embodiment of the present application can also transmit the real-time detected temperature data to the controller in real time, as the control basis of the first three-way valve V1, the fifth three-way valve, the heater 1, the fan 3 and other execution elements. For example, when the fifth temperature detection device T5 does not meet the standard, the first three-way valve V1 keeps the first interface and the third interface connected to concentrate preheating; after the first temperature detection device T1 meets the standard, the first three-way valve V1 is switched to the second interface and the third interface connected, and the third three-way valve V3 is switched to the second interface and the third interface connected, so that the high-temperature cooling liquid enters the heating loop.

[0060] Therefore, the fifth temperature sensor monitors the stack inlet temperature to ensure that the heat of the heater 1 in the starting stage is concentrated for stack preheating until the set temperature is reached, solving the problem of difficult equipment start-up in the prior art in a low-temperature environment, especially in a-30℃ ultra-low temperature environment, which can avoid the start-up failure or performance degradation of the stack caused by insufficient temperature. By monitoring the stack outlet temperature through the first temperature detection device T1, the opening time of the heating loop is controlled, for example, only when the stack generates sufficient waste heat, the seat and leg heating is started, avoiding the waste of energy when the waste heat of the stack is insufficient (such as in the starting stage), optimizing the utilization efficiency of 50%-60% waste heat of the hydrogen fuel cell, and reducing the invalid loss of "waste heat dissipation in the form of heat exchange".

[0061] The real-time feedback of the temperature detected by the first temperature detection device T1 and the second temperature detection device T2 enables the management system of the embodiment of the present application to adapt to a wide temperature range environment from -30℃ to +5℃. For example, when the ambient temperature is extremely low (such as -30℃) and the temperature detected by the fifth temperature detection device T5 rises slowly, the controller prolongs the heating time of the heater 1 to ensure that the stack is fully preheated. When the operating load of the stack increases (such as high-intensity work), the temperature detected by the first temperature detection device T1 rises rapidly, and the controller accelerates the heat output of the heating circuit (such as increasing the rotation speed of the fan 3) to avoid overheating of the stack. The temperature detection and the arrangement of the temperature detection device and its dynamic response capability improve the stability of the system in a complex low-temperature environment.

[0062] In summary, the settings of the fifth temperature sensor and the first temperature sensor enable the system to achieve "reliable low-temperature startup" and "precise utilization of residual heat". In the embodiment of the present application, the inlet and outlet cooling liquid temperatures of the hydrogen fuel cell stack 5 are monitored in real time to provide control basis for the controller, which not only solves the problem of stack startup in a low-temperature environment, but also optimizes the timing and intensity of residual heat utilization. Compared with traditional low-temperature forklifts (internal combustion engine, pure electric vehicle type), the system has a significant improvement in energy efficiency and environmental adaptability, solves the technical problem of limited application scenarios in the prior art, and achieves the effect of improving energy utilization.

[0063] Specifically, in the hydrogen fuel cell thermal management system suitable for a low-temperature environment provided by the embodiment of the present application, the second temperature detection device T2 is arranged on the heat exchange pipe 9.

[0064] In this way, by directly installing the second temperature detection device T2 on the heat exchange pipe 9 inside the seat, the temperature of the heat exchange pipe 9 (indirectly reflecting the surface temperature of the seat) is monitored in real time. Since the heat exchange pipe 9 heats the seat through heat conduction, its temperature is highly correlated with the actual temperature of the seat, and therefore the detection data of the second temperature detection device T2 can accurately reflect the temperature state of the seat contacted by the driver. In addition, after the controller receives the temperature signal of the second temperature detection device T2, it can also trigger corresponding adjustment actions by comparing with the preset temperature threshold (such as the lower and upper limits of the comfortable temperature of the seat). For example, when the temperature detected by the second temperature detection device T2 is lower than the set lower limit, the controller turns on the heater 1, and controls the third three-way valve V3 and the fourth three-way valve V4 to keep the heating circuit unblocked, so as to improve the temperature of the seat by using "fuel cell residual heat + heater 1 auxiliary heating". When the second temperature detection device T2 reaches the set limit, the controller turns off the heater 1 and only relies on the residual heat of the fuel cell to maintain the temperature. When the temperature detected by the second temperature detection device T2 is higher than the set upper limit, the controller switches the three-way valve passage (such as closing the heating circuit by V3) to stop the heating of the seat to avoid overheating.

[0065] Thus, the second temperature detection device T2 ensures that the seat temperature is stable in the comfortable range (e.g. 5-25℃) by monitoring the seat temperature in real time. For example, in an ultra-low temperature environment of -30℃, if the second temperature detection device T2 is too low, the system automatically increases the heating; if the second temperature detection device T2 is too high, the heating is stopped in time to avoid the driver being affected by the seat being too cold or too hot, thus solving the problem of poor driver operating environment in the prior art due to the lack of heating devices in forklifts in low temperature environments. The second temperature detection device T2 detects the temperature of the heat exchange pipe 9, so that the seat heating is changed from "continuous output" to "on-demand adjustment", and heating is started only when the seat temperature is insufficient, and stopped when the temperature meets the standard, thus avoiding the energy waste caused by traditional "constant power heating", further improving the energy utilization rate of the hydrogen fuel cell system. In addition, when the hydrogen fuel cell waste heat and the heater 1 work together, if there is no temperature monitoring of the second temperature detection device T2, the seat may be locally overheated (especially in a closed cabin), but through the temperature detection of the second temperature detection device T2, such risks can be effectively avoided, thus ensuring the safety of the driver and the service life of the seat components.

[0066] In summary, through real-time monitoring and closed-loop control of the second temperature detection device T2, the problem of poor driving comfort in low temperature environments is solved, the energy distribution is optimized, the waste is avoided, the safety and intelligence of the system are enhanced, and the purpose of improving the energy utilization rate of the hydrogen fuel cell and improving the driving environment is further achieved.

[0067] In some optional implementations of the embodiment, a third temperature detection device T3 is arranged on the pipeline between the third three-way valve V3 and the power battery 8.

[0068] Specifically, by installing the third temperature detection device T3 on the pipeline through which the cooling liquid flows into the power battery 8, the temperature of the cooling liquid entering the power battery 8 can be directly monitored. Since the cooling liquid exchanges heat with the battery when flowing through the power battery 8 (preheating or heat dissipation), the detection data of the third temperature detection device T3 can accurately reflect the temperature environment of the power battery 8. In addition, according to the feedback signal of the third temperature detection device T3, the controller adjusts the operation of related components in combination with preset threshold values (such as the minimum temperature required for starting the power battery 8 and the normal working temperature range), for example, in the starting stage: if the third temperature detection device T3 is lower than the starting threshold value of the power battery 8, the controller controls the heater 1 to continuously work, and at the same time, the cooling liquid circuit is concentrated to the power battery 8 through the first and third three-way valves to deliver heat until the third temperature detection device T3 reaches the set temperature; in the running stage: if the temperature detected by the third temperature detection device T3 is too high (such as the power battery 8 generates heat due to charging and discharging), the controller intensifies heat dissipation through the radiator 4 (such as increasing the rotation speed of the fan 3) to make the cooling liquid take away the excess heat of the power battery 8; if the temperature detected by the third temperature detection device T3 is too low, the controller uses the waste heat of the power battery to heat the cooling liquid to ensure that the power battery 8 works at an appropriate temperature and avoids capacity attenuation caused by low temperature.

[0069] In some optional implementations of the embodiments of the present application, a fourth temperature detection device T4 is arranged between the radiator 4 and the leg cover of the driver's seat.

[0070] By installing the fourth temperature detection device T4 between the radiator 4 and the leg cover (i.e., the key area around the driver's legs), the air temperature in this area can be directly monitored. Since the radiator 4 heats the environment around the legs through convection air, the detection data of the fourth temperature detection device T4 can accurately reflect the actual heating effect of the driver's legs. In addition, after the controller receives the temperature signal of the fourth temperature detection device T4, the temperature signal is compared with the preset threshold values (such as the lower limit and the upper limit of the comfortable temperature of the legs) to trigger corresponding adjustments: for example, when the temperature detected by the fourth temperature detection device T4 is lower than the set lower limit, the controller starts the heater 1 and controls the fan 3 to run at the maximum speed (to intensify the convection heating) to increase the temperature of the legs by using the "waste heat of the fuel cell + auxiliary heating of the heater 1"; when the fourth temperature detection device T4 reaches the set limit, the heater 1 is turned off and the temperature is maintained only by the waste heat of the fuel cell; when the temperature detected by the fourth temperature detection device T4 is higher than the set upper limit, the controller closes the heating circuit through the third and fourth three-way valves to stop the heating of the legs to avoid overheating.

[0071] Therefore, in the embodiment of the present application, the fourth temperature detection device T4 monitors the leg temperature to ensure that the region is stable in the comfortable interval (such as 5-20℃). For example, in an ultra-low temperature environment of-30℃, if the fourth temperature detection device T4 is too low, the system automatically strengthens heating; if the fourth temperature detection device T4 is too high, it is stopped in time to avoid the driver's operation efficiency or health being affected due to cold legs, and the problem of the driver's poor operation environment due to the need for long-term and frequent operation of the forklift in the prior art and the lack of heating equipment in most vehicles is solved. In addition, the fourth temperature detection device T4 starts heating only when the leg temperature is insufficient, and stops the additional energy consumption when the temperature meets the standard, thereby avoiding the energy waste of the traditional heating method.

[0072] In some optional implementations of the embodiment of the present application, an atomizer 11 is further included, and the atomizer 11 is connected to the third interface of the water storage tank 10.

[0073] Specifically, when the hydrogen fuel cell is running, a large amount of water vapor is contained in the tail gas, which first flows through the seat heat exchange pipe 9, and the condensed water in the seat heat exchange pipe 9 enters the water storage tank 10 for storage. The water in the water storage tank 10 is connected to the atomizer 11 through a pipeline, and when there is a local humidification demand in a low-temperature environment (such as a cold storage) (triggered by manual operation of the driver), the atomizer 11 atomizes the water into small droplets and releases them to the target area (such as the cargo storage area or the cockpit), thereby achieving local humidity regulation. In addition, the operation of the atomizer 11 does not affect the core heating function of the thermal management system, and the water source thereof is completely from the recovered water vapor of the hydrogen fuel cell tail gas, without the need for additional water supply, thereby forming a closed loop of “tail gas water vapor-heat utilization-water vapor recovery-atomization humidification”.

[0074] Therefore, in the embodiment of the present application, the hydrogen fuel cell tail gas water vapor is recovered as an atomization water source, without the need for additional energy consumption to generate water vapor (such as the heating energy consumption of a hot steam system), thereby greatly reducing the operation cost of local humidification, solving the technical problem of high cost of humidification in an ultra-low temperature environment and local humidification in the prior art, such as the humidification of a cold storage mainly relying on a freeze-proof high-pressure micro-fog system and a hot steam diffusion humidification system, and simultaneously, in the embodiment of the present application, the hydrogen fuel cell tail gas water vapor is originally dissipated in the form of “tail gas water vapor”, and the atomizer 11 is arranged to convert it into a useful resource (humidification water source), thereby forming synergy with the waste heat recovery (heating of the seat and the legs), further improving the energy and resource comprehensive utilization rate of the system, and realizing multiple utilization of “hydrogen-electricity-heat-water”.

[0075] As shown in Figure 1 the working process of the hydrogen fuel cell thermal management system suitable for a low-temperature environment provided by the embodiment of the present application includes:

[0076] In the hydrogen fuel cell starting process, the heater 1 is turned on to heat the coolant. The first three-way valve V1 has the first port and the third port connected, and the second port closed. The second three-way valve V2 has the first port and the second port connected, and the third port closed. The third three-way valve V3 has the first port and the second port connected, and the third port closed. The fourth three-way valve V4 has the second port and the third port connected, and the first port closed. The shut-off valve V6 is closed. The coolant flows through the hydrogen fuel cell stack 5 and the power battery 8. At this time, the fan 3 is not running. After the inlet temperature of the hydrogen fuel cell stack 5 and the inlet temperature of the power battery 8 reach the set temperature detected by the fifth temperature detection device T5 and the third temperature detection device T3, the hydrogen fuel cell (hydrogen fuel cell system) starts normally and outputs according to the target power. After the hydrogen fuel cell starts, the heater 1 is turned off, the shut-off valve V6 is opened, the second port and the third port of the first three-way valve V1 are connected, and the first port is closed. The second three-way valve V2 is adjusted according to the hydrogen fuel cell control strategy (control strategy in the hydrogen fuel cell controller FCU). The first port and the second port of the third three-way valve V3 are connected, and the third port is closed. The second port and the third port of the fourth three-way valve V4 are connected, and the first port is closed. At this time, the fan 3 is not running.

[0077] In the hydrogen fuel cell running process, when the first temperature detection device T1 at the fourth outlet of the hydrogen fuel cell stack 5 reaches the set value, the second port and the third port of the first three-way valve V1 are connected, and the first port is closed. The second port and the third port of the third three-way valve V3 are connected, and the first port is closed. At this time, the coolant flowing out of the fourth port of the hydrogen fuel cell stack 5, the coolant flowing out of the second port of the intercooler 7, and the coolant flowing out of the third port of the air compressor 6 are combined and flow into the seat internal coolant side metal heat exchange pipe 9 through the third port of the third three-way valve V3, heating the driver's seat. The coolant flowing out of the seat coolant metal heat exchange pipe 9 is heat exchanged by the power battery 8 water cooling system, and then enters the radiator 4 for forced convection heat exchange. The fan 3 runs at a speed according to the fuel cell control strategy, and the heated air is brought out from the hood heat dissipation hole and blown towards the driver's legs. The second three-way valve V2 is adjusted according to the hydrogen fuel cell control strategy. The first port and the second port of the fourth three-way valve V4 are connected, and the third port is closed. Part of the pressurized air flows out through the third port of the second three-way valve V2, and then flows through the first port and the second port of the fourth three-way valve V4, combining with the exhaust gas flowing out of the third port of the hydrogen fuel cell stack 5 and the exhaust gas flowing out of the first port and the second port of the back pressure regulating valve V5, and then entering the seat internal air side metal heat exchange pipe 9, heating the driver's seat. At the same time, the water in the exhaust gas is stored in the water storage tank 10, and according to the environmental needs, the driver can manually operate to atomize and humidify the local environment through the atomizer 11.

[0078] In the process of heating the seat, the second temperature detecting device T2 inside the seat, the fourth temperature detecting device T4 detecting the temperature of the driver's leg environment are read, when the temperature detected by the second temperature detecting device T2 or the fourth temperature detecting device is lower than the set lower limit value, the heater 1 is turned on, the seat and the driver's leg around are heated by the heater 1 and the fuel cell system, the second interface and the third interface of the first three-way valve V1 are communicated, the first interface is closed, the second three-way valve V2 is adjusted according to the hydrogen fuel cell control strategy, the second interface and the third interface of the third three-way valve V3 are communicated, the first interface is closed, the first interface and the second interface of the fourth three-way valve V4 are communicated, the third interface is closed, and the fan 3 operates at the maximum speed. When the temperature detected by the second temperature detecting device T2 or the fourth temperature detecting device reaches the set limit value, the heater 1 is turned off, and only the waste heat of the hydrogen fuel cell system is used for heating the seat and the driver's leg. When the temperature detected by the second temperature detecting device T2 or the fourth temperature detecting device reaches the set upper limit value, the first interface and the second interface of the third three-way valve V3 are communicated, the third interface is closed, the second interface and the third interface of the fourth three-way valve V4 are communicated, the first interface is closed, the second interface and the third interface of the first three-way valve V1 are communicated, the first interface is closed, the second three-way valve V2 is adjusted according to the hydrogen fuel cell control strategy, the heating of the seat and the driver's leg around is stopped, and the fan 3 operates at the speed according to the fuel cell control strategy.

[0079] Therefore, the hydrogen fuel cell thermal management system provided by the embodiment of the application is suitable for a low-temperature environment, the heat generated by the heat dissipation of the stack, the heat dissipation of the intercooler 7 and the electric supercharger is transferred to the seat heat exchange pipe 9 through heat exchange when the hydrogen fuel cell operates, and the heat of the exhaust gas is further transferred to the seat heat exchange pipe 9, so that the seat is directly heated in a heat conduction mode. The exhaust gas flows through the seat heat exchange pipe 9 to release the waste heat, and then enters the water storage tank 10, so that the waste heat-exhaust gas, seat heating and water vapor recovery are used in stages.

[0080] In addition, in the embodiment of the application, the driver's leg heating includes directional utilization of convection heat dissipation, the radiator 4 is arranged at the position of the forklift seat hood, the hood is designed as a grid, the heat dissipation of the stack and related components is transferred to the radiator 4 through the cooling liquid, the air around the driver's leg is heated by using the convection air, and the waste heat is directionally used to improve the driving environment. The water vapor in the hydrogen fuel cell exhaust gas flows through the seat heat exchange pipe 9 (after the waste heat is released) and enters the water storage tank 10 for storage; the water storage tank 10 is connected with the atomizer 11, the stored water can be atomized through the atomizer 11 according to the environmental requirements (such as insufficient local humidity), directional and low-cost local humidification is realized, and the high energy consumption of the traditional high-pressure micro-fog or hot steam system is avoided.

[0081] In addition, in the embodiment of the present application, the system is self-adaptive based on the feedback and adjustment of the temperature detection device and the controller, for example, in the starting stage: the cooling liquid is preheated by the heater 1, combined with the feedback of the water temperature sensor (such as the inlet temperature of the fuel cell and the inlet temperature of the power battery 8), and the hydrogen fuel cell is started after the temperature reaches the standard, to ensure the stable starting of the system at low temperature; in the running stage: the first to fourth three-way valves V4, the back pressure regulating valve V5, the stop valve V6 and the rotating speed of the fan 3 are adjusted according to the real-time data of the cooling liquid temperature detection device at the outlet of the fuel cell, the seat temperature detection device and the leg environment temperature detection device, the heater 1 is started when the second temperature detection device T2 or the temperature detection device is lower than the set value, and the heating is strengthened together with the waste heat of the fuel cell; the heating circuit is closed when the second temperature detection device T2 or the fourth temperature detection device T4 is higher than the set value, to avoid overheating; at the same time, in the embodiment of the present application, the water in the water storage tank 10 is atomized to realize local humidification according to the environmental requirements through the manual operation of the driver to trigger the atomizer 11.

[0082] In summary, the hydrogen fuel cell thermal management system provided by the embodiment of the present application is suitable for low temperature environment, takes the hydrogen fuel cell as the core, recovers heat by heating the seat and the leg with the waste heat, realizes the closed loop utilization of water vapor and the dynamic temperature adjustment mode, solves the limitations of the traditional low temperature forklift in the aspects of scene emission, endurance and heating, improves the energy utilization rate of the hydrogen fuel cell system, and realizes the effects of environmental protection, high efficiency and comfort.

[0083] It should be noted that, in this document, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Additionally, reference to "front", "back", "left", "right", "up", "down", or the like, in this document are made solely with reference to the orientation of the figures as presented in the drawings.

[0084] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A hydrogen fuel cell thermal management system suitable for use in cryogenic environments, characterized in that, The application comprises: a heater, a first interface of which is connected to a first interface of a water pump through a pipeline; a first three-way valve, a first interface of which is connected to a second interface of the heater through a pipeline, and a second interface of which is connected to the pipeline between the first interface of the water pump and the first interface of the heater; a third three-way valve, a second interface of which is connected to the pipeline between the heater and the first interface of the first three-way valve; a radiator, which is arranged at a leg cover position of a driver's seat, one end of which is connected to a first interface of the third three-way valve through a pipeline, and the pipeline connecting the radiator and the first interface of the third three-way valve passes through a power battery, so that the power battery is cooled and the cooled heat is used to heat the driver's seat leg, and the other end of the radiator is connected to a second interface of the water pump; a hydrogen fuel cell stack, a first interface of which is connected to a third interface of the first three-way valve through a pipeline; an air compressor, a first interface of which is connected to the pipeline of the second interface of the first three-way valve, and a second interface of which is an air side for inputting external air; an intercooler, a first interface of which is connected to the pipeline of the second interface of the first three-way valve, a second interface of which is connected to the pipeline between a third interface of the air compressor and a second interface of the third three-way valve, and a fourth interface of which is connected to a second interface of the hydrogen fuel cell stack; a second three-way valve, a first interface of which is connected to a third interface of the intercooler, and a second interface of which is connected to a fourth interface of the air compressor; a heat exchange pipe, which is arranged inside a driver's seat, a first interface of which is connected to a third interface of the third three-way valve, and a second interface of which is connected to the pipeline between the first interface of the third three-way valve and the radiator; a water storage tank, a first interface of which is connected to a fourth interface of the heat exchange pipe; a back pressure regulating valve, a first interface of which is connected to a third interface of the hydrogen fuel cell stack, and a second interface of which is connected to a third interface of the heat exchange pipe; a fourth three-way valve, a first interface of which is connected to the pipeline between the second interface of the back pressure regulating valve and the third interface of the heat exchange pipe, a second interface of which is connected to a third interface of the second three-way valve, and a third interface of which is connected to a second interface of the water storage tank; a stop valve, a first interface of which is connected to a third interface of the air compressor, and a second interface of which is connected to the pipeline of the second interface of the third three-way valve. A fifth temperature detecting device is arranged on the pipeline between the first three-way valve and the hydrogen fuel cell stack, and a fourth interface of the hydrogen fuel cell stack is connected to the pipeline between the second interface of the stop valve and the second interface of the third three-way valve, and a first temperature detecting device is arranged on the pipeline of the fourth interface of the hydrogen fuel cell stack; A second temperature detecting device is arranged on the heat exchange pipeline; A third temperature detecting device is arranged on the pipeline between the third three-way valve and the power battery; A fourth temperature detecting device is arranged between the radiator and the leg cover of the driver's seat; The device further comprises an atomizer connected to the third interface of the water storage tank.

2. A hydrogen fuel cell thermal management system suitable for use in cryogenic environments according to claim 1, wherein, The heater comprises a PTC heater.

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