Hydrogen fuel stack thermal management apparatus and method for mobile hydrogen production plants

Abstract

The application provides a hydrogen fuel stack heat management device and method for a movable hydrogen production device, the hydrogen fuel stack of the movable hydrogen production device has a cooling liquid outlet, a cooling liquid inlet and a stack temperature sensor, the heat management device comprises a waste heat unit, a cooling liquid circulation loop pipeline connected from the cooling liquid outlet to the cooling liquid inlet and filled with cooling liquid and a control unit electrically connected with the stack temperature sensor; the waste heat unit comprises a waste heat heat exchanger, a cylinder body, a piston, a heat dissipation assembly and a semiconductor refrigeration sheet. The heat management device and method can realize functions such as rapid cooling liquid temperature adjustment, efficient energy recovery and intelligent heat management control by adding the waste heat unit.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy, and specifically to a thermal management device and method for a hydrogen fuel cell stack in a mobile hydrogen production device. Background Technology

[0002] Hydrogen fuel cells (stacks) are clean energy conversion devices that generate a lot of heat during operation. The operating temperature of the stack directly affects its power generation efficiency, service life and safety.

[0003] Existing thermal management systems typically employ a combination of circulating coolant and radiators, but these systems suffer from several drawbacks: low heating efficiency and long preheating times during low-temperature startup, impacting system response speed; insufficient heat dissipation capacity during high-temperature operation, particularly under high-power output conditions; and low overall energy utilization efficiency, with a significant amount of waste heat not being effectively recovered and utilized. This is especially problematic in mobile hydrogen production units where space constraints make it difficult for traditional thermal management solutions to simultaneously meet the dual requirements of rapid temperature control and energy recovery.

[0004] Therefore, there is a need to develop a thermal management device that can achieve efficient thermal management, make full use of system waste heat, and has a compact structure. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a thermal management device and method for a hydrogen fuel cell stack in a mobile hydrogen production device. By adding a waste heat unit, it can achieve functions such as rapid adjustment of coolant temperature, efficient energy recovery and intelligent thermal management control.

[0006] Accordingly, the present invention also provides a thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production device, wherein the hydrogen fuel cell stack of the mobile hydrogen production device has a coolant outlet, a coolant inlet, and a stack temperature sensor;

[0007] The thermal management device includes a waste heat unit, a coolant circulation loop pipe that connects from the coolant outlet to the coolant inlet and is filled with coolant, and a control unit that is electrically connected to the fuel cell stack temperature sensor.

[0008] The waste heat unit includes a waste heat exchanger, a cylinder, a piston, a heat dissipation assembly, and a semiconductor refrigeration chip.

[0009] The semiconductor cooling chip is disposed on the piston. The cylinder is divided into a working fluid chamber and a coolant chamber based on the piston. The working fluid chamber has a working fluid inlet, and the coolant chamber has a fluid inlet and a fluid outlet. A first one-way limiting structure is disposed on the fluid inlet, and an unloading valve is disposed on the fluid outlet. The fluid inlet and the fluid outlet are respectively connected to the coolant circulation loop pipe.

[0010] The waste heat exchanger is fitted onto the coolant circulation loop pipeline, and the waste heat exchanger is connected to the working fluid inlet and transfers the heat-conducting working fluid.

[0011] The heat dissipation assembly includes a heat dissipation element and an energy conversion module. The energy conversion module is connected between the fluid outlet and the coolant circulation loop pipe to convert the kinetic energy of the coolant flowing through the energy conversion module into the driving energy of the heat dissipation element. The heat dissipation element is driven to dissipate heat for the heat-conducting working medium and / or the coolant based on the driving energy.

[0012] The control unit is electrically connected to the semiconductor cooling chip and the energy conversion module, respectively.

[0013] In an optional embodiment, an inlet temperature sensor is provided on the coolant circulation loop pipe at a position corresponding to the fluid inlet, and an outlet temperature sensor is provided at a position corresponding to the fluid outlet.

[0014] The control unit is electrically connected to the inlet temperature sensor and the outlet temperature sensor, respectively.

[0015] In an optional implementation, the inlet temperature sensor and the outlet temperature sensor are respectively powered by a thermoelectric generator.

[0016] In an optional implementation, the waste heat unit further includes a waste heat radiator;

[0017] The working fluid chamber also has a working fluid outlet, which is connected to the waste heat exchanger after passing through the waste heat radiator.

[0018] A second unidirectional limiting structure is provided between the waste heat radiator and the waste heat exchanger, which is open in the direction from the waste heat radiator to the waste heat exchanger.

[0019] In an optional implementation, a pressure overflow structure is provided at the working fluid outlet.

[0020] In an optional embodiment, the piston has a cylindrical structure formed by protruding from the outer edge of its surface facing the working fluid cavity.

[0021] The working fluid outlet is located on the side wall of the cylinder body;

[0022] When the piston moves from the working fluid chamber towards the coolant chamber and has not reached the preset position, the working fluid outlet is closed to the working fluid chamber based on the piston and the cylindrical structure; after the piston moves from the working fluid chamber towards the coolant chamber and reaches the preset position, the working fluid outlet is connected to the working fluid chamber.

[0023] In an optional embodiment, an elastic damping element is provided between the cylindrical structural member and the cylinder body.

[0024] In an optional implementation, the energy conversion module includes a turbine generator.

[0025] Accordingly, the present invention provides a thermal management method for a hydrogen fuel cell stack in a mobile hydrogen production device, implemented based on the aforementioned thermal management equipment, including an active thermal management process;

[0026] The active thermal management process includes:

[0027] The control unit receives feedback temperature information from the fuel cell temperature sensor;

[0028] When the feedback temperature information is lower than the lower limit of the threshold temperature range, the semiconductor refrigeration chip is activated and the current direction of the semiconductor refrigeration chip is controlled to drive the semiconductor refrigeration chip to heat one side of the cooling liquid cavity.

[0029] When the feedback temperature information is higher than the upper limit of the threshold temperature range, the thermoelectric cooler is activated and the current direction of the thermoelectric cooler is controlled to drive the thermoelectric cooler toward one side of the coolant chamber for cooling.

[0030] In an optional implementation, when the feedback temperature information is higher than the upper limit of the threshold temperature range, the thermoelectric cooler is activated and the current direction of the thermoelectric cooler is controlled to drive the thermoelectric cooler toward the side of the coolant chamber for cooling for a first preset time. If the feedback temperature information is still higher than the upper limit of the threshold temperature range, the current direction of the thermoelectric cooler is reversed and controlled for a second preset time.

[0031] In summary, this invention provides a thermal management device and method for a hydrogen fuel cell stack in a mobile hydrogen production device. This thermal management device utilizes the rapid thermoelectric effect of a semiconductor cooling chip to quickly regulate the temperature of the stack coolant, significantly improving the speed of low-temperature start-up and enhancing heat dissipation performance under extreme high temperatures. The innovative waste heat recovery design converts waste heat energy into useful mechanical and electrical energy, improving the overall energy efficiency of the entire system and reducing system energy consumption. In practical applications, the control system can automatically optimize operating parameters according to the working status, ensuring that the stack always operates within the optimal temperature range and guaranteeing normal operation. Multiple protection designs ensure safe operation of the system under various working conditions, and the structural design, through a purely mechanical structure, enables the utilization of waste heat without consuming additional electrical energy. The use of elastic damping components greatly improves the shock resistance and service life of the waste heat recovery unit. Attached Figure Description

[0032] Figure 1 This is a structural diagram of a hydrogen fuel cell stack thermal management device module for a mobile hydrogen production device according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the waste heat unit structure according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic cross-sectional view of the waste heat exchanger according to an embodiment of the present invention.

[0035] Figure 4 This is a flowchart of the active thermal management process according to an embodiment of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Figure 1 This is a structural diagram of a hydrogen fuel cell stack thermal management device module for a mobile hydrogen production device according to an embodiment of the present invention. Solid lines represent coolant circulation loop pipes, arrows indicate coolant flow direction, and dashed lines represent electrical (signal) connections. For clarity, the detailed structure of the preheating unit will be described later. (See attached diagram.) Figure 1 The diagram is shown in only the block diagram.

[0038] This invention provides a thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production device. Basically, the hydrogen fuel cell stack is equipped with a coolant outlet, a coolant inlet, and a stack temperature sensor.

[0039] The thermal management device includes the following components:

[0040] The coolant circulation system includes coolant circulation loop pipes, a main radiator, and an electric water pump. The coolant circulation loop pipes connect the coolant outlet to the coolant inlet, forming a complete closed-loop circulation system. The pipes are filled with a coolant of a specific formula, which has good thermal conductivity and fluidity. The main radiator adopts a finned tube structure, which has a large heat dissipation area to ensure heat dissipation performance under high load conditions. It is generally located on the windward side of the mobile hydrogen production unit and is usually equipped with a main cooling fan to dissipate heat and ensure heat dissipation performance when the mobile hydrogen production unit is stationary. The electric water pump can be driven by a brushless DC motor, which has the characteristics of adjustable flow rate, low noise, and long life. It should be noted that in the description of the coolant circulation system in this embodiment of the invention, only the two most critical components (main radiator and electric water pump) are listed. In actual implementation, the structure of the coolant circulation system is more complex, and it can be designed according to existing technology.

[0041] The control system includes a control unit with multiple analog and digital input / output interfaces. It is capable of processing various sensor signals in real time and outputting control commands. Essentially, the control unit is electrically connected to components such as the fuel cell stack temperature sensor, electric water pump, and main cooling fan. Its specific operation will be described later. It should be noted that the description of the control system in this embodiment only lists the most critical component (the control unit). In actual implementation, the control system generally includes various types of sensors, and various electronically controlled devices in the coolant circulation system also require control by the control unit. In actual implementation, the design can be based on existing technology.

[0042] The waste heat unit includes components such as a waste heat exchanger, cylinder 4, piston 6, heat dissipation components, and semiconductor refrigeration chip 5. The waste heat unit is a supplementary functional unit of the coolant circulation system, mainly used for the recovery and utilization of waste heat and to perform the heating function required by the coolant circulation system (cold start of the fuel cell stack). In practical applications, there can be multiple waste heat units.

[0043] It should be noted that the thermal management device in this embodiment of the invention is actually a structure with the addition of a waste heat unit to the existing hydrogen fuel cell stack and its peripheral configuration structure for mobile hydrogen production devices. The waste heat unit can be added and modified on the basis of the existing hydrogen fuel cell stack equipment. Only minor adjustments to its original structure and control logic of the original equipment are required according to the description.

[0044] Figure 2 This is a schematic diagram of the waste heat unit structure according to an embodiment of the present invention. The structure on one side of the cylinder 4 is shown in cross-sectional view. For clarity, some common parts are shown using symbols defined by national standards, and some structures are shown in block diagram form and will be further illustrated in subsequent figures.

[0045] The following structural diagrams illustrate the specific structure of the waste heat unit.

[0046] Cylinder 4

[0047] Refer to the attached diagram. Figure 2 As shown in the diagram, the cylinder body 4 is made of high-strength aluminum alloy. The piston 6 divides its interior into two independent chambers, named the working fluid chamber and the coolant chamber according to their function. To ensure the stability of the piston 6's movement, a guide rod 3 is slidably fitted onto the piston body to guide its movement.

[0048] Basicly, the working fluid chamber has a working fluid inlet 9 for introducing the heat transfer fluid 8; the coolant chamber has a fluid inlet 1 and a fluid outlet 13. In practical applications, both fluid inlet 1 and fluid outlet 13 can be connected to the coolant circulation loop pipeline via quick connectors. Specifically, the location of fluid inlet 1 and fluid outlet 13 affects the contribution of the waste heat unit to the entire coolant circulation system. On the one hand, the closer the connection point of fluid inlet 1 to the coolant circulation loop pipeline is to the coolant outlet of the fuel cell stack, the more waste heat the heat transfer fluid 8 can acquire. On the other hand, the connection point of fluid outlet 13 to the coolant circulation loop pipeline affects the effective position of the heat-treated coolant. When multiple heat exchange units are set up, diverse thermal management effects can be achieved by flexibly configuring the connection positions of fluid inlet 1 and fluid outlet 13 of the cylinder block 4.

[0049] Specifically, a first one-way limiting structure 2 is provided at the fluid inlet 1. The first one-way limiting structure 2 can adopt a spring-loaded ball valve design to ensure that the coolant can only flow into the coolant chamber in one direction. An unloading valve 12 is provided at the fluid outlet 13. When the pressure in the chamber exceeds the set value, it will open automatically. Through the cooperative design of the first one-way limiting structure 2 and the unloading valve 12, the coolant chamber can actually be understood as a pressurization chamber. After the piston 6 pressurizes the coolant in the coolant chamber, when the pressure of the coolant reaches a certain level, the unloading valve 12 opens and the high-pressure liquid is quickly discharged under the drive of the piston 6, so that the high-pressure liquid has huge kinetic energy.

[0050] Semiconductor cooling chip 5

[0051] The thermoelectric cooler 5 is installed at the center of the piston 6. The two sides of the thermoelectric cooler 5 are in contact with the working fluid chamber and the coolant chamber, respectively. Heating or cooling of the coolant chamber can be achieved by changing the direction of the current. An annular sealing structure is provided around the thermoelectric cooler 5 to ensure complete isolation between the two chambers.

[0052] Waste heat exchanger

[0053] Figure 3This is a schematic cross-sectional view of the waste heat exchanger according to an embodiment of the present invention.

[0054] The waste heat exchanger adopts a clamp-type structure, which is tightly fitted onto the coolant circulation loop pipeline. By contacting the outer wall of the pipeline, it transfers the heat from the coolant circulation loop pipeline to the heat transfer medium 8. The waste heat exchanger has a microchannel structure inside, which is connected to the working medium inlet 9 through a sealed joint, ensuring that the heat transfer medium 8 can flow efficiently and absorb the waste heat in the coolant.

[0055] Heat dissipation components

[0056] The heat dissipation assembly includes a heat dissipation element and an energy conversion module. The energy conversion module is connected between the fluid outlet 13 and the coolant circulation loop pipe, and is used to convert the kinetic energy of the coolant flowing through the energy conversion module into the driving energy of the heat dissipation element.

[0057] In this embodiment of the invention, the energy conversion module employs a micro turbine generator design, connected between the fluid outlet 13 and the coolant circulation loop pipe. When the coolant flows through the energy conversion module, it drives the turbine to rotate and generate electricity, converting the fluid's kinetic energy into electrical energy. The generated electrical energy is used to drive the heat dissipation element, which employs an axial fan design to provide forced convection cooling for the heat transfer medium 8 (waste heat radiator) and / or the coolant (main radiator). It should be noted that the power generation of the turbine can be designed to match the opening pressure of the unloading valve 12, ensuring that the kinetic energy of the discharged high-pressure coolant can be effectively converted into electrical energy.

[0058] Specifically, if the conversion efficiency is not considered, the energy conversion module can directly adopt an impeller structure, and the heat dissipation element can be a fan. The impeller structure can be used to directly drive the fan to rotate. However, this implementation will waste some of the kinetic energy of the coolant, and the high-pressure, high-velocity coolant will rush into the coolant circulation loop pipe.

[0059] Temperature monitoring components

[0060] (Refer to the attached diagram) Figure 1 The schematic diagram shows that the temperature monitoring component includes an inlet temperature sensor and an outlet temperature sensor. An inlet temperature sensor is installed on the coolant circulation loop pipe at the location corresponding to fluid inlet 1, and an outlet temperature sensor is installed at the location corresponding to fluid outlet 13. Specifically, the temperature sensors can be PT100 platinum resistance temperature sensors, with a measurement accuracy of ±0.1℃. The control unit is electrically connected to both the inlet and outlet temperature sensors to monitor the temperature change of the coolant in real time after it enters the heat exchange unit.

[0061] Preferably, the inlet temperature sensor and the outlet temperature sensor are each powered by a thermoelectric generator. The thermoelectric generator generates electricity using the temperature difference between the coolant and the environment, enabling the sensors to operate on their own and reducing system energy consumption.

[0062] Waste heat radiator

[0063] In practical implementation, to accelerate the heat dissipation of the heat-conducting working fluid 8, in addition to passive heat dissipation, a loop-type circulating heat dissipation method can be implemented by setting up a waste heat radiator to improve heat dissipation efficiency. Specifically, the waste heat unit also includes a waste heat radiator, and correspondingly, the working fluid chamber is also provided with a working fluid outlet 11. This outlet is connected to the waste heat radiator through a pipe, and the outlet of the waste heat radiator is then connected to the waste heat exchanger to form a circulation loop. A second one-way restriction structure 10 (a one-way valve can be selected) is provided between the waste heat radiator and the waste heat exchanger to ensure unidirectional flow of the heat-conducting working fluid 8. In practical implementation, the waste heat radiator can be located on the opposite side of the main radiator from the windward side.

[0064] Corresponding to the setting of the waste heat radiator, a pressure overflow structure (a pressure overflow valve can be selected) is also provided at the working fluid outlet 11. On the one hand, it provides overpressure protection when the working fluid chamber pressure rises abnormally. On the other hand, since the heat-conducting working fluid 8 in this embodiment of the invention also has the function of driving the piston 6 to move, the pressure driving source of the piston 6 depends not only on the pressure provided after the entire circulation loop is heated, but also on the pressure of the heat-conducting working fluid 8 in the working fluid chamber by setting the pressure overflow structure, so as to better drive the movement of the piston 6.

[0065] Furthermore, in order to increase the reciprocating stroke of piston 6 and thus improve the pumping efficiency of piston 6 for coolant, unlike the method of setting an overflow structure, in actual implementation, a cylindrical structure 7 can be formed by protruding on the outer edge of the piston 6 facing the working fluid chamber, and the working fluid outlet 11 can be set on the side wall of cylinder 4. When piston 6 moves from the working fluid chamber towards the coolant chamber but has not reached the preset position, the working fluid outlet 11 is completely sealed by piston 6 and cylindrical structure 7. When piston 6 reaches the preset position, the working fluid outlet 11 connects with the working fluid chamber, allowing the heat-conducting working fluid 8 to flow out. Through this design, the huge pressure generated by the thermal expansion or vaporization of the heat-conducting working fluid 8 is confined within the working fluid chamber. When the pressure in the working fluid chamber rises to a certain level, the unloading valve 12 of the coolant chamber is opened, and the coolant is squeezed out by piston 6. After piston 6 moves to the corresponding side of the coolant chamber until the working fluid outlet 11 is opened, the high-pressure heat-conducting working fluid 8 can also be discharged from the working fluid outlet 11 and dissipated by the waste heat radiator. When the unloading valve 12 is closed, the coolant re-enters the coolant chamber, and after piston 6 is pushed back to close the working fluid outlet 11, the working fluid chamber re-enters the pressurization process.

[0066] Furthermore, considering the collision between the cylindrical structural component 7 and the cylinder body 4, an elastic damping component can be placed between the cylindrical structural component 7 and the cylinder body 4 inside the cylinder body 4. The elastic damping component is made of silicone rubber material, which has good buffering performance and high temperature resistance, and can effectively absorb the impact vibration when the piston 6 moves.

[0067] Accordingly, this invention also provides a thermal management method for a hydrogen fuel cell stack in a mobile hydrogen production device. From an active management perspective, the thermal management method for a hydrogen fuel cell stack in a mobile hydrogen production device mainly uses temperature data from the stack temperature sensor to adjust the operation of related equipment to ensure that the coolant temperature meets the stack's operating requirements.

[0068] Figure 4 This is a flowchart of the active thermal management process according to an embodiment of the present invention.

[0069] Specifically, the thermal management method includes an active thermal management process, which includes:

[0070] S101: The control unit receives feedback temperature information from the fuel cell temperature sensor;

[0071] S102: When the feedback temperature information is lower than the lower limit of the threshold temperature range, control the semiconductor cooling chip to start and control the current direction of the semiconductor cooling chip so that the semiconductor cooling chip heats the side facing the cooling liquid cavity.

[0072] When the semiconductor cooling chip is heated on the side facing the coolant chamber, the coolant in the coolant chamber will be heated. When the coolant is at room temperature, the unloading valve will not be opened. Only when the temperature of the coolant rises to a certain temperature will the volume expansion generate sufficient pressure to open the unloading valve.

[0073] Specifically, for the most common automotive proton exchange membrane fuel cell (PEMFC) with a required coolant temperature (70 to 90 degrees Celsius), the temperature of the coolant discharged from the coolant chamber is generally higher than 100 degrees Celsius. The opening pressure of the unloading valve needs to be designed in combination with the coolant volume expansion pressure at this temperature and the thermal expansion or thermal vaporization pressure provided by the heat transfer medium. The purpose of designing the coolant discharge temperature to be higher than the coolant temperature required by the fuel cell stack is that the coolant in the coolant circulation loop contains coolant at room temperature. When the coolant in the coolant chamber is discharged, it will mix with the coolant in the coolant circulation loop and transfer heat. Therefore, it is necessary to increase the temperature of the discharged coolant.

[0074] Furthermore, it should be noted that, as described above regarding the location of the fluid outlet, the location of the fluid outlet of the heat exchange unit in the coolant circulation loop pipeline can be flexibly adjusted. Therefore, based on the functional requirements of this step, in this embodiment of the invention, at least one set of heat exchange unit fluid outlets is connected to the coolant circulation loop pipeline near the fuel cell stack coolant inlet, thereby ensuring that the appropriate coolant for fuel cell stack operation can be quickly supplied to the fuel cell stack, guaranteeing the response speed of fuel cell stack startup. Moreover, if system complexity is not a consideration, in practical applications, the fluid outlets can be connected to different locations in the coolant circulation loop pipeline, controlled by relevant electric shut-off valves, thereby flexibly adjusting the discharge position of the heat-treated coolant in the coolant circulation loop pipeline. Correspondingly, the coolant circulation loop pipeline can be equipped with multiple openable and closable joints for fluid outlet connection to improve the flexibility of installation operations. The heat exchange unit of this embodiment can also be used for the retrofitting of existing hydrogen production units to improve the waste heat utilization capacity of the hydrogen production unit.

[0075] Furthermore, when the hot end of the thermoelectric cooler is heating, the cold end will cool accordingly. Consequently, the working fluid on one side of the working fluid chamber will be cooled. Although the cooled working fluid will affect the corresponding waste heat exchanger, causing a local decrease in the coolant temperature in the coolant circulation loop pipe at the waste heat exchanger, the waste heat exchanger is generally located on the side closer to the coolant outlet than the fluid outlet. Since the high-temperature coolant in this embodiment is unloaded collectively into the coolant circulation loop pipe and quickly enters the fuel cell stack in a short time, the fuel cell stack starts up quickly. Therefore, when the fuel cell stack is started, the coolant temperature on the coolant outlet side will rise rapidly, which will quickly offset the cooling effect of the thermoelectric cooler and ensure the normal operation of the entire thermal management system.

[0076] S103: When the feedback temperature information is higher than the upper limit of the threshold temperature range, the semiconductor refrigeration chip is activated and the current direction of the semiconductor refrigeration chip is controlled so that the semiconductor refrigeration chip cools the side of the cooling liquid chamber.

[0077] Generally, step S102 occurs during the cold start phase of the fuel cell stack, while step S103 is a response to abnormal temperature rise of the coolant. It usually occurs when the mobile hydrogen production unit is stationary and the fuel cell stack is driven at full power (neutral throttle). Since the main radiator fails to generate sufficient heat through airflow, a semiconductor cooling chip is needed to actively cool the coolant.

[0078] Correspondingly, when the thermoelectric cooler cools the side facing the coolant chamber, it cools the coolant. Correspondingly, the hot end of the thermoelectric cooler heats the heat-conducting medium. The heat-conducting medium expands or vaporizes when heated, providing pressure to the piston. When the pressure reaches a certain level, the coolant opens the unloading valve and is discharged to cool the coolant in the coolant circulation loop pipe. The low-temperature coolant discharged near the coolant inlet quickly cools the coolant input to the fuel cell stack, ensuring responsiveness.

[0079] Furthermore, when the feedback temperature is higher than the threshold temperature, the thermoelectric cooler is activated, and the direction of its current is controlled. After the thermoelectric cooler cools the side facing the coolant chamber for a first preset time, if the feedback temperature is still higher than the upper limit of the threshold temperature range, the direction of the current in the thermoelectric cooler is reversed and maintained for a second preset time. This step aims to prevent the piston from being blocked and unable to retract, ensuring successful piston retraction by cooling and depressurizing the heat-conducting medium. It also accelerates the reciprocating motion of the piston, improving the pumping efficiency of the cryogenic coolant. Generally, the second preset time is shorter than the first preset time. During this coolant heating process, since the unloading valve is closed again, the temporarily heated coolant will not enter the coolant circulation loop pipe.

[0080] The above describes the active thermal management process in the thermal management method of this invention. When the feedback temperature information is within the threshold temperature range, the waste heat unit of this invention can also passively utilize waste heat to promote the circulation efficiency of the coolant and assist the coolant in heat dissipation. This is referred to as the waste heat recovery process in this invention.

[0081] Specifically, the waste heat recovery process includes the following steps:

[0082] S201: Waste heat collection;

[0083] When the coolant flows through the waste heat exchanger, it transfers some of its heat to the heat transfer medium.

[0084] S202: Energy conversion;

[0085] The heated heat-conducting working fluid enters the working fluid chamber, pushing the piston to move, which in turn drives the coolant to flow.

[0086] S203: Kinetic energy generation;

[0087] The outflowing coolant drives the energy conversion module to generate electricity, which powers the heat dissipation element. The heat dissipation element enhances the cooling effect on the waste heat radiator, improving the overall heat dissipation efficiency.

[0088] In summary, this invention provides a thermal management device and method for a hydrogen fuel cell stack in a mobile hydrogen production device. This thermal management device utilizes the rapid thermoelectric effect of a semiconductor cooling chip to quickly regulate the temperature of the stack coolant, significantly improving the speed of low-temperature start-up and enhancing heat dissipation performance under extreme high temperatures. The innovative waste heat recovery design converts waste heat energy into useful mechanical and electrical energy, improving the overall energy efficiency of the entire system and reducing system energy consumption. In practical applications, the control system can automatically optimize operating parameters according to the working status, ensuring the stack always operates within the optimal temperature range and guaranteeing normal operation. Multiple protection designs ensure safe operation of the system under various working conditions, and the structural design, through a purely mechanical structure, enables the utilization of waste heat without consuming additional electrical energy. The use of elastic damping components greatly improves the shock resistance and service life of the waste heat recovery unit.

[0089] The foregoing has provided a detailed description of a thermal management device and method for a mobile hydrogen production device's hydrogen fuel cell stack, as provided in the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production unit, wherein the hydrogen fuel cell stack of the mobile hydrogen production unit has a coolant outlet, a coolant inlet, and a stack temperature sensor; Its features are, The thermal management device includes a waste heat unit, a coolant circulation loop pipe that connects from the coolant outlet to the coolant inlet and is filled with coolant, and a control unit that is electrically connected to the fuel cell stack temperature sensor. The waste heat unit includes a waste heat exchanger, a cylinder, a piston, a heat dissipation assembly, and a semiconductor refrigeration chip. The semiconductor cooling chip is disposed on the piston. The cylinder is divided into a working fluid chamber and a coolant chamber based on the piston. The working fluid chamber has a working fluid inlet, and the coolant chamber has a fluid inlet and a fluid outlet. A first one-way limiting structure is disposed on the fluid inlet, and an unloading valve is disposed on the fluid outlet. The fluid inlet and the fluid outlet are respectively connected to the coolant circulation loop pipe. The waste heat exchanger is fitted onto the coolant circulation loop pipeline, and the waste heat exchanger is connected to the working fluid inlet and transfers the heat-conducting working fluid. The waste heat unit also includes a waste heat radiator, and the working fluid chamber also has a working fluid outlet. The working fluid outlet is connected to the waste heat exchanger after passing through the waste heat radiator. A second unidirectional restriction structure is provided between the waste heat radiator and the waste heat exchanger, which is open in the direction from the waste heat radiator to the waste heat exchanger. The piston has a cylindrical structure formed by protruding from the outer edge of its surface facing the working fluid cavity; the working fluid outlet is disposed on the side wall of the cylinder; when the piston moves from the working fluid cavity towards the coolant cavity and has not reached the preset position, the working fluid outlet and the working fluid cavity are closed based on the piston and the cylindrical structure; after the piston moves from the working fluid cavity towards the coolant cavity and reaches the preset position, the working fluid outlet communicates with the working fluid cavity; The heat dissipation assembly includes a heat dissipation element and an energy conversion module. The energy conversion module is connected between the fluid outlet and the coolant circulation loop pipe to convert the kinetic energy of the coolant flowing through the energy conversion module into the driving energy of the heat dissipation element. The heat dissipation element is driven to dissipate heat for the heat-conducting working medium and / or the coolant based on the driving energy. An inlet temperature sensor is installed on the coolant circulation loop pipe at a position corresponding to the fluid inlet, and an outlet temperature sensor is installed at a position corresponding to the fluid outlet; the control unit is electrically connected to the inlet temperature sensor and the outlet temperature sensor respectively. The control unit is electrically connected to the semiconductor cooling chip and the energy conversion module, respectively.

2. The thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production unit as described in claim 1, characterized in that, The inlet temperature sensor and the outlet temperature sensor are powered by thermoelectric generators.

3. The thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production unit as described in claim 1, characterized in that, A pressure overflow structure is provided at the outlet of the working fluid.

4. The thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production unit as described in claim 1, characterized in that, An elastic damping element is provided between the cylindrical structural component and the cylinder body.

5. The thermal management device for a hydrogen fuel cell stack in a mobile hydrogen production unit as described in claim 1, characterized in that, The energy conversion module includes a turbine generator.

6. A method for thermal management of a hydrogen fuel cell stack in a mobile hydrogen production unit, characterized in that, The thermal management device according to any one of claims 1 to 5 is implemented, including an active thermal management process; The active thermal management process includes: The control unit receives feedback temperature information from the fuel cell temperature sensor; When the feedback temperature information is lower than the lower limit of the threshold temperature range, the semiconductor refrigeration chip is activated and the current direction of the semiconductor refrigeration chip is controlled to drive the semiconductor refrigeration chip to heat one side of the cooling liquid cavity. When the feedback temperature information is higher than the upper limit of the threshold temperature range, the thermoelectric cooler is activated and the current direction of the thermoelectric cooler is controlled to drive the thermoelectric cooler toward one side of the coolant chamber for cooling.

7. The method for thermal management of a hydrogen fuel cell stack for a mobile hydrogen production device as described in claim 6, characterized in that, When the feedback temperature information is higher than the upper limit of the threshold temperature range, the thermoelectric cooler is activated and the current direction of the thermoelectric cooler is controlled to drive the thermoelectric cooler toward the side of the coolant chamber for cooling for a first preset time. If the feedback temperature information is still higher than the upper limit of the threshold temperature range, the current direction of the thermoelectric cooler is reversed and controlled for a second preset time.

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