Fuel cell waste heat cascade utilization and hydrogen storage coupling system

Abstract

The application discloses a hydrogen energy thermal management technical field and discloses a fuel cell waste heat cascade utilization and hydrogen storage coupling system, which comprises a fuel cell system, at least two hydrogen storage units, a water circulation loop and a hydrogen circuit; the water circulation loop comprises a waste heat exchange branch, an auxiliary heating branch and a hydrogen storage heat exchange branch; the water circulation loop is provided with a hydrogen storage three-way valve, and the waste heat exchange branch, the auxiliary heating branch and the hydrogen storage heat exchange branch are in shunt communication through the hydrogen storage three-way valve; the waste heat exchange branch is provided with a partition heat exchanger and a heat exchange three-way valve, and the partition heat exchanger is provided with a primary side and a secondary side which are isolated from each other; a water outlet end of the fuel cell system is connected to the primary side through the heat exchange three-way valve, and the water outlet of the primary side flows back to the fuel cell system through a heat dissipation three-way valve; and the secondary side inlet is connected to a shunt outlet of the hydrogen storage three-way valve; the problems of high energy consumption in low-temperature starting, low waste heat utilization rate, quick loss of the hydrogen storage unit and overpressure of the shutdown pressure difference are solved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy thermal management technology, specifically to a fuel cell waste heat cascade utilization and hydrogen storage coupling system. Background Technology

[0002] Existing fuel cell and solid-state hydrogen storage systems consist of two independent thermal management loops. The waste heat generated during fuel cell operation is difficult to reuse in a cascade manner, and hydrogen release relies entirely on electric heaters for heating. Under low-temperature conditions, the hydrogen release efficiency of hydrogen storage alloys is low, resulting in high energy consumption and long start-up time for the system. Furthermore, the waste heat supply varies greatly between different power operating conditions of fuel cells, and traditional single heat exchange loops cannot dynamically allocate waste heat and electric heating heat, leading to low waste heat utilization.

[0003] Meanwhile, the use of synchronous start-stop control for multiple hydrogen storage units makes it impossible to operate in tiers with the load, which exacerbates the loss of hydrogen storage materials; when the unit is shut down, there is a hydrogen pressure difference between the hydrogen storage units, which can easily lead to hydrogen cross-flow and insufficient safety performance; the fuel cell cooling circuit and the hydrogen storage heating circuit interfere with each other, and there is a lack of integrated structure for graded heat dissipation, independent voltage regulation, and multi-sensor monitoring.

[0004] Therefore, existing coupling systems suffer from drawbacks such as high energy consumption during low-temperature start-up, insufficient waste heat recovery, poor coordination among multiple hydrogen storage units, and inadequate operational safety assurance. Summary of the Invention

[0005] The technical solution of this invention is to provide a fuel cell waste heat cascade utilization and hydrogen storage coupling system, which solves the problems of high energy consumption during low-temperature start-up, low waste heat utilization rate, rapid loss of hydrogen storage unit, and overpressure during shutdown in existing systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a fuel cell waste heat cascade utilization and hydrogen storage coupling system, comprising a fuel cell system, at least two hydrogen storage units, a water circulation loop, and a hydrogen circulation loop, characterized in that: The water circulation loop includes a waste heat exchange branch, an auxiliary heating branch, and a hydrogen storage heat exchange branch; the water circulation loop is equipped with a hydrogen storage three-way valve, and the waste heat exchange branch, the auxiliary heating branch, and the hydrogen storage heat exchange branch are connected and separated through the hydrogen storage three-way valve. The waste heat exchange branch is equipped with a partition heat exchanger and a heat exchange three-way valve. The partition heat exchanger has a primary side and a secondary side that are isolated from each other for heat exchange. The water outlet of the fuel cell system is connected to the primary side through the heat exchange three-way valve. The water outlet of the primary side flows back to the fuel cell system through the heat dissipation three-way valve. The secondary side inlet is connected to a branch outlet of the hydrogen storage three-way valve. The inlet of the auxiliary heating branch is connected to another branch outlet of the hydrogen storage three-way valve. The outlet of the auxiliary heating branch merges with the secondary side outlet of the partition heat exchanger and is connected to the water supply end of the hydrogen storage heat exchange branch. A heater is installed on the auxiliary heating branch. The hydrogen storage heat exchange branch is equipped with a circulation pump, and each hydrogen storage unit is equipped with a water valve. The water circuits of each hydrogen storage unit are arranged in parallel, and the effluent flows back to the inlet of the circulation pump to form a closed loop. The hydrogen circuit includes a hydrogen supply branch, and each hydrogen storage unit is equipped with a hydrogen valve at its hydrogen supply end. The outlets of all the hydrogen valves converge and are connected to the hydrogen supply branch.

[0007] As a further embodiment of the present invention, it also includes a control unit, which is electrically connected to a heat dissipation three-way valve, a heat exchange three-way valve, a hydrogen storage three-way valve, various water valves, various hydrogen valves, and a heater.

[0008] As a further aspect of the present invention, a heat sink is also included; The three-way radiator valve has one inlet and two outlets. Its inlet is connected to the primary side outlet of the partition heat exchanger, and its two outlets are respectively connected to the return water port of the fuel cell system and the inlet of the radiator. The outlet of the radiator is connected to the return water port of the fuel cell system.

[0009] As a further embodiment of the present invention, the three ports of the hydrogen storage three-way valve are the main water supply inlet, the waste heat exchange port and the heating branch port, respectively. The main water supply inlet is connected to the water from the circulating pump, and the waste heat exchange port and the heating branch port are respectively connected to the secondary side inlet of the partition wall heat exchanger and the inlet of the heater. The hydrogen storage three-way valve can adjust the on / off state of the waste heat exchange port and the heating branch port, as well as the medium diversion ratio.

[0010] As a further embodiment of the present invention, the circulation pump and the check valve are sequentially provided on the water supply main pipe of the water circulation loop along the water flow direction; The number of hydrogen storage units is specifically four; each of the hydrogen storage units is equipped with a water valve on its inlet side; Each hydrogen storage unit is equipped with a hydrogen storage outlet water temperature sensor at its outlet end, and the hydrogen storage heat exchange branch is equipped with a solid storage inlet temperature sensor and a water pressure sensor on its water supply side.

[0011] As a further embodiment of the present invention, the hydrogen circuit also includes a hydrogen refueling branch; A hydrogen filter is installed on the hydrogen refueling branch. The hydrogen filter has a hydrogen filling interface at the inlet and multiple hydrogen refueling pipelines at the outlet. Each hydrogen refueling pipeline is equipped with a one-way valve, and each one-way valve is connected to the hydrogen refueling end of each hydrogen storage unit. Each of the hydrogen storage units is equipped with a hydrogen pressure sensor.

[0012] As a further embodiment of the present invention, the hydrogen storage heat exchange branch is provided with an external cooling pipeline, and an inlet quick connector and an outlet quick connector are respectively provided at both ends of the external cooling pipeline; the inlet quick connector is used to connect to external cold water, and the outlet quick connector is used to discharge the cooling water after heat exchange.

[0013] As a further embodiment of the present invention, the hydrogen supply branch is provided with a pressure reducing valve, a shut-off valve and a hydrogen supply metal hose in sequence along the airflow direction, and the hydrogen supply branch is also provided with a pressure relief valve in parallel.

[0014] As a further embodiment of the present invention, the water circulation loop is further provided with a solid storage expansion tank and a main expansion tank; The main expansion tank is connected to the cooling return water pipe between the radiator and the fuel cell system, and the solid storage expansion tank is connected to the outlet water return pipe of the hydrogen storage unit in the hydrogen storage heat exchange branch. The primary outlet of the partition heat exchanger is equipped with a heat exchanger outlet water temperature sensor, and the outlet of the fuel cell system is equipped with a battery outlet water temperature sensor.

[0015] A method for coupled control of fuel cell waste heat utilization and hydrogen storage includes the following operating condition control steps: S1. Cold Start Control: When starting in a low-temperature environment, the heater is activated to heat the circulating water, and the hydrogen storage three-way valve is controlled to cut off the waste heat exchange port, so that the circulating water flows through the heater, the hydrogen storage heat exchange branch, and each of the hydrogen storage units in sequence before returning to the circulation pump, providing the heat required for hydrogen release to the hydrogen storage units; the hydrogen valve of the corresponding hydrogen storage unit is opened, and the hydrogen is delivered to the fuel cell system after being pressure regulated by the pressure reducing valve; S2. Waste Heat Dynamic Distribution Control: The operating power of the fuel cell system is monitored in real time. When operating at low power, the heat exchange three-way valve is controlled to guide all the fuel cell outlet water into the primary side of the indirect heat exchanger. At the same time, the hydrogen storage three-way valve is controlled to divert the circulating water to the waste heat exchange branch and the auxiliary heating branch. The waste heat from the fuel cell and the auxiliary heating from the heater jointly supply heat to the hydrogen storage circuit. When operating at high power, the hydrogen storage three-way valve is controlled to cut off the auxiliary heating branch. All the circulating water absorbs the waste heat from the fuel cell through the indirect heat exchanger. At the same time, the heat dissipation three-way valve is controlled to guide the primary side outlet water into the radiator for heat dissipation and then return. S3. Cascaded hydrogen supply control: According to the power requirements of the fuel cell system, the water valves and hydrogen valves of the corresponding number of hydrogen storage units are opened in sequence to match the hydrogen supply capacity and load power as needed; at the same time, based on the hydrogen pressure sensor detection values ​​of each hydrogen storage unit, units with sufficient hydrogen storage pressure are given priority for operation. S4. Shutdown Equalization Control: When the fuel cell system is shut down, the heat dissipation three-way valve is first controlled to introduce the primary side water into the radiator to complete the system cooling. Then, the hydrogen valves of all the hydrogen storage units are opened to connect the hydrogen circuits of each hydrogen storage unit to achieve hydrogen pressure equalization between units.

[0016] In step S3, the cascaded hydrogen supply opens the water valve and hydrogen valve corresponding to each hydrogen storage unit in ascending order of power; when the power of the fuel cell system decreases, the water valve and hydrogen valve corresponding to each hydrogen storage unit are closed in reverse order.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, a heat exchanger with a hydrogen storage three-way valve is used to construct a dual heat source heating circuit of waste heat and electric heating. The single / dual heating circuit can be switched according to the operating conditions of the fuel cell system, so as to fully recover the waste heat of the fuel cell system, reduce the energy consumption of the heater, and improve the energy utilization efficiency.

[0018] 2. In this invention, under low-temperature cold start conditions, the hydrogen storage three-way valve cuts off the residual heat exchange channel and only conducts the heater to form a closed heating cycle, which quickly increases the temperature of the hydrogen storage unit, shortens the system cold start time, and solves the problem of slow hydrogen release from hydrogen storage alloys in low-temperature environments.

[0019] 3. In this invention, each hydrogen storage unit is equipped with an independent water valve and a hydrogen valve, which can be activated in stages according to the load power. This eliminates the crude control mode of synchronous start-stop of all hydrogen storage units, balances the hydrogen charging and discharging frequency of each hydrogen storage unit, extends the service life of the hydrogen storage alloy, and reduces unnecessary heating energy consumption.

[0020] 4. In this invention, when the system is shut down, all hydrogen valves open synchronously, the hydrogen circuits of all hydrogen storage units are interconnected, and the hydrogen in the tanks flows freely until the pressure of each hydrogen storage unit is unified, eliminating the hydrogen pressure difference between tanks, avoiding hydrogen crossflow and local overpressure caused by pressure difference, and improving the safety of system shutdown and the stability of the next startup. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a schematic diagram of the waste heat exchange branch process of the present invention; Figure 3 This is a schematic diagram of the hydrogen storage heat exchange branch process of the present invention; Figure 4 This is a schematic diagram of the hydrogen supply branch process of the present invention; Figure 5 This is a schematic diagram of the hydrogenation branch process of the present invention; The attached diagram lists the components represented by each number as follows: 1. Main expansion tank; 2. Cooling three-way valve; 3. Radiator; 4. Heat exchange three-way valve; 5. Battery outlet water temperature sensor; 6. Fuel cell system; 7. Hydrogen supply metal hose; 8. Shut-off valve; 9. Pressure relief valve; 10. Pressure reducing valve; 11. Circulation pump; 12. Check valve; 13. Solid storage inlet temperature sensor; 14. Water valve; 18. Hydrogen valve; 22. One-way valve; 25. Hydrogen filter; 26. Hydrogen charging interface; 28. Hydrogen storage outlet water temperature sensor; 32. Hydrogen storage three-way valve; 33. Solid storage expansion tank; 34. Heat exchanger outlet water temperature sensor; 35. Indirect heat exchanger; 36. Outlet quick connector; 37. Heater; 38. Inlet quick connector; 39. Water pressure sensor; 40. Hydrogen storage unit; 44. Hydrogen pressure sensor; 73. Waste heat exchange port; 74. Main water supply inlet; 75. Heating branch port. Detailed Implementation

[0023] 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.

[0024] Please see Figures 1-5 The present invention provides a technical solution: A fuel cell waste heat utilization and hydrogen storage coupling system includes a fuel cell system 6, at least two hydrogen storage units 40, a water circulation loop, and a hydrogen circulation loop. The water circulation loop includes a waste heat exchange branch, an auxiliary heating branch, and a hydrogen storage heat exchange branch; the water circulation loop is equipped with a hydrogen storage three-way valve 32, and the waste heat exchange branch, the auxiliary heating branch, and the hydrogen storage heat exchange branch are connected and separated through the hydrogen storage three-way valve 32. The waste heat exchange branch is equipped with a partition heat exchanger 35 and a heat exchange three-way valve 4. The partition heat exchanger 35 is equipped with a primary side and a secondary side that are isolated from each other for heat exchange. The outlet of the fuel cell system 6 is connected to the primary side through the heat exchange three-way valve 4. The outlet of the primary side is returned to the fuel cell system 6 through the heat dissipation three-way valve 2. The secondary side inlet is connected to a branch outlet of the hydrogen storage three-way valve 32. The inlet of the auxiliary heating branch is connected to another branch outlet of the hydrogen storage three-way valve 32. The outlet of the auxiliary heating branch merges with the secondary side outlet of the partition heat exchanger 35 and is connected to the water supply end of the hydrogen storage heat exchange branch. A heater 37 is installed on the auxiliary heating branch. The hydrogen storage heat exchange branch is equipped with a circulation pump 11, and a water valve 14 is provided for each hydrogen storage unit 40. The water circuits of each hydrogen storage unit 40 are arranged in parallel, and the effluent flows back to the inlet of the circulation pump 11 to form a closed loop. The hydrogen circuit includes a hydrogen supply branch. Each hydrogen storage unit 40 is equipped with a hydrogen valve 18 at its hydrogen supply end. The outlets of all hydrogen valves 18 converge and are connected to the hydrogen supply branch. Primary side general circulation process: Cooling water flows out of the primary side outlet of the indirect heat exchanger 35, and the water flows through the heat dissipation three-way valve 2, fuel cell system 6, and heat exchange three-way valve 4 in sequence, and then flows back into the indirect heat exchanger 35 from the primary side inlet to complete a single cycle. The fuel cell system 6 generates heat continuously during operation. High-temperature cooling water flows out of the fuel cell system 6 and is sent to the primary side of the partition heat exchanger 35 through the heat exchange three-way valve 4. It completes heat exchange with the low-temperature water on the secondary side and releases heat. The cooling water after heat exchange and cooling flows out from the primary side outlet and is directly returned to the fuel cell system 6 through the heat dissipation three-way valve 2, continuously circulating and carrying away the heat generated by the fuel cell system 6.

[0025] Secondary side general circulation process: The circulation pump 11 outputs heated circulating water, which is first delivered to each water valve 14, and then flows into the corresponding hydrogen storage unit 40 after passing through the water valve 14. The water releases heat inside the hydrogen storage unit 40, providing a heat source for the hydrogen storage alloy to release hydrogen. The low-temperature water flow from each hydrogen storage unit 40 is collected and sent to the hydrogen storage three-way valve 32. After the water flow reaches the hydrogen storage three-way valve 32, it can be divided into two independent branches: Branch 1: Water flows into the secondary side of the partition wall heat exchanger 35, where it exchanges heat with the high-temperature cooling water on the primary side, absorbing the waste heat from the fuel cell system 6 to raise its temperature. Branch 2: Water flows into the heater 37 and is heated by electricity to raise the water temperature; the two heated water flows merge into a main pipe and are then transported to the inlet of the circulation pump 11 to form an uninterrupted closed-loop circulation.

[0026] General hydrogen circuit process: Hydrogen storage unit 40 releases hydrogen when heated, and the corresponding hydrogen valve 18 opens. The hydrogen from each circuit is collected and delivered to fuel cell system 6 for continuous power supply.

[0027] Process of each working condition

[0028] Operating Condition 1: Low Temperature Cold Start Condition (Fuel Cell System 6 is not started, and no waste heat is generated)

[0029] Water circuit control: The hydrogen storage three-way valve 32 closes the waste heat exchange branch channel and only opens the auxiliary heating branch where the heater 37 is located, while all water valves 14 are opened; the secondary side relies solely on the heater 37 to complete the circulating temperature rise.

[0030] Hydrogen circuit control: All hydrogen valves 18 are opened, and all hydrogen storage units 40 are supplied with hydrogen synchronously to start the fuel cell system 6.

[0031] Operating effect: When there is no residual heat at low temperature, the heater 37 provides heat independently, which can quickly increase the temperature of the hydrogen storage unit 40, shorten the system start-up time, and solve the problem of slow hydrogen release at low temperature.

[0032] Operating Condition 2: Low-power operation of the fuel cell system (insufficient waste heat, with waste heat and electric auxiliary heating working together).

[0033] Primary side control: Heat exchange three-way valve 4 allows all cooling water to enter the primary side of the partition heat exchanger 35, and heat dissipation three-way valve 2 connects directly to the return pipeline.

[0034] Secondary side control: The hydrogen storage three-way valve 32 simultaneously opens the waste heat exchange branch and the auxiliary heating branch, and opens the water valve 14 of the corresponding hydrogen storage unit 40 according to the load, so that the waste heat and electric heating are supplied simultaneously.

[0035] Hydrogen circuit control: Only the hydrogen valve 18 corresponding to the hydrogen storage unit 40 that is in operation is opened to match the hydrogen supply demand of the load.

[0036] Operating effect: Fully utilize the small amount of waste heat from the fuel cell system 6, and supplement the insufficient heat by the heater 37, reducing the energy consumption of electric heating and ensuring stable hydrogen release from the hydrogen storage unit 40.

[0037] Operating Condition 3: Fuel Cell System Operating Conditions at 6 High Power Levels (Sufficient Waste Heat, Electric Auxiliary Heating Off)

[0038] Primary side control: All the high-temperature cooling water of the fuel cell system 6 is fed into the indirect heat exchanger 35 for primary side heat exchange. After heat exchange, the cooling water is returned to the fuel cell system 6 through the heat dissipation three-way valve 2.

[0039] Secondary side control: The hydrogen storage three-way valve 32 cuts off the heater 37 branch and only opens the waste heat exchange branch. The heater 37 stops and relies entirely on the indirect heat exchanger 35 to recover waste heat for heating.

[0040] Hydrogen circuit control: Simultaneously open the hydrogen valves 18 corresponding to multiple hydrogen storage units 40 to increase the total hydrogen supply to adapt to high power loads.

[0041] Operating effect: The heater 37 is completely shut down, and the hydrogen storage unit 40 is heated only by the waste heat of the fuel cell system 6, maximizing the recovery of waste heat and significantly reducing the energy consumption of the system operation.

[0042] Operating Condition 4: Hydrogen storage unit 40-stage hydrogen supply operation (the number of operating hydrogen storage units 40 is dynamically increased or decreased according to the load)

[0043] Water circuit control: When the load is low, only the water valve 14 corresponding to a single hydrogen storage unit 40 is opened; when the power increases, the remaining water valves 14 are opened one by one, and when the power decreases, they are closed in reverse order; the hydrogen storage three-way valve 32 selects single-path / dual heat source heating according to the power of the fuel cell system 6; hot water is introduced into the hydrogen storage unit 40 with only the water valve 14 open to participate in hydrogen release.

[0044] Hydrogen circuit control: Water valve 14 and hydrogen valve 18 of the same group of hydrogen storage units 40 are opened and closed synchronously, and only hydrogen gas output from the corresponding hydrogen storage unit 40 is activated.

[0045] Operating effect: The synchronous start-stop mode of all 40 hydrogen storage units is abandoned, the hydrogen charging and discharging frequency of each 40 hydrogen storage unit is balanced, the service life of the hydrogen storage alloy is extended, and the useless energy consumption caused by continuous heating is reduced.

[0046] Operating Condition 5: Fuel Cell System Shutdown Equalization Condition

[0047] Water circuit control: Stop the operation of circulation pump 11, the water circulation stops as a whole, and the hydrogen storage three-way valve 32 maintains any passage, with no medium flow.

[0048] Hydrogen circuit control: All hydrogen valves 18 open synchronously, the hydrogen circuits of each hydrogen storage unit 40 are interconnected, and hydrogen gas flows freely within the hydrogen storage unit 40 until the pressure is uniform.

[0049] Operating effect: Eliminates hydrogen pressure difference between multiple hydrogen storage units 40, avoids hydrogen crossflow and local overpressure caused by pressure difference during shutdown, and improves system shutdown safety and stability for the next startup.

[0050] Overall Implementation Effect

[0051] Two independent water circulation systems are built for the primary cooling side of the fuel cell and the secondary heating side of the hydrogen storage. The heat exchanger 35 is used to isolate the hot and cold media and prevent them from mixing. The hydrogen storage three-way valve 32 realizes the flexible allocation of waste heat recovery and electric auxiliary heat sources. Each hydrogen storage unit 40 is turned on and off by an independent water valve 14. Hydrogen is collected and transported in a unified manner through the hydrogen valve 18. The hardware structure solves the industry pain points of insufficient heating at low temperature start-up and the inability to fully recover and utilize the working heat of the fuel cell system 6.

[0052] As a further improvement, the system is also equipped with a control unit; the control unit is electrically connected to the heat dissipation three-way valve 2, the heat exchange three-way valve 4, the hydrogen storage three-way valve 32, each water valve 14, each hydrogen valve 18, and the heater 37 respectively. The control unit is connected to the drive actuators of the heat dissipation three-way valve 2, the heat exchange three-way valve 4, and the hydrogen storage three-way valve 32 via control lines, and can output opening adjustment and on / off switching control signals. At the same time, the control unit independently controls the water valve 14 and hydrogen valve 18 of each hydrogen storage unit 40, and independently realizes the opening and closing of the water circuit and hydrogen circuit of a single hydrogen storage unit 40. The control unit is also connected to the power supply circuit of the heater 37, and can control the start and stop of the heater 37 and adjust the heating power. A centralized control unit is added to manage all system components. It can automatically switch all operating conditions according to the real-time operating status of the fuel cell system and standardize the execution logic of preheating, waste heat distribution, cascade hydrogen supply, shutdown pressure equalization, and hydrogen addition cooling, which greatly reduces manual operation and improves the consistency and safety stability of system operation.

[0053] As a further improvement, the system also includes a radiator 3; the three-way radiator 2 has one inlet and two outlets. The inlet of the three-way radiator 2 is connected to the primary side outlet of the partition heat exchanger 35, and the two outlets of the three-way radiator 2 are respectively connected to the return water port of the fuel cell system 6 and the inlet of the radiator 3. The outlet of the radiator 3 is connected to the return water port of the fuel cell system 6. The water flow first enters the inlet of the three-way valve 2, and then splits into two paths depending on the switching state of the three-way valve 2: Passage 1 (low power straight-through mode): The heat dissipation three-way valve 2 is switched to the straight-through outlet, and the cooling water flows directly through the return water port of the fuel cell system 6 back to the inside of the fuel cell system 6 without passing through the radiator 3, thus retaining the waste heat completely to supply heat exchange for hydrogen storage. Passage 2 (High-power heat dissipation mode): The heat dissipation three-way valve 2 is switched to the radiator branch outlet, and the cooling water flows into the radiator 3 for forced heat dissipation and cooling. The cooled water flows out from the outlet of the radiator 3 and then flows back to the return water port of the fuel cell system 6 to dissipate the excess heat of the system. After the cooling water flows back to the fuel cell system 6, it is sent back to the primary side of the indirect heat exchanger 35 via the heat exchange three-way valve 4 to complete the complete primary side cycle.

[0054] By adding a radiator 3 in conjunction with a three-way cooling valve 2, the fuel cell cooling circuit can be cooled in stages. In low-power operation, the radiator 3 is isolated to maximize the retention of residual heat from the fuel cell stack to supply the hydrogen storage unit 40 and reduce the energy consumption of the heater 37. In high-power operation, the radiator 3 is automatically connected to dissipate excess heat to prevent high-temperature damage to the fuel cell system 6, taking into account both the utilization rate of residual heat and the safety of fuel cell stack operation, and improving the system's thermal balance control capability under all operating conditions.

[0055] As a further embodiment of the present invention, the hydrogen storage three-way valve 32 is provided with three interfaces, namely the main water supply inlet 74, the waste heat exchange port 73 and the heating branch port 75. The main water supply inlet 74 is connected to the incoming water output from the circulating pump 11, the waste heat exchange port 73 is connected to the secondary side inlet of the partition heat exchanger 35, and the heating branch port 75 is connected to the inlet of the heater 37. The hydrogen storage three-way valve 32 can independently adjust the on / off state of the waste heat exchange port 73 and the heating branch port 75, and can also precisely adjust the flow ratio of the two media. The low-temperature return water collected from each hydrogen storage unit 40 flows into the main water supply inlet 74 of the hydrogen storage three-way valve 32. After the medium enters the hydrogen storage three-way valve 32, it is distributed in two ways according to the regulating state of the hydrogen storage three-way valve 32: Single-path conduction mode: Only the waste heat exchange port 73 or only the heating branch port 75 is opened, and all the medium flows into a single branch to complete the heating. Dual-path synchronous conduction mode: Waste heat exchange port 73 and heating branch port 75 are opened simultaneously, and the medium (i.e., low temperature return water) is diverted to the two branches in a set ratio to absorb heat and rise in temperature simultaneously. The two heated media converge at the end of the pipeline and flow back to the circulation pump 11 to form a complete closed loop. By directionally arranging the three interfaces of the hydrogen storage three-way valve 32, centralized distribution of return water on the hydrogen storage side is achieved; the valve can flexibly switch between single-path / dual-path working modes, and at the same time accurately adjust the water flow ratio of the two paths, which can dynamically match the waste heat recovery amount and electric auxiliary heat supplementation amount according to different power conditions of the fuel cell system 6, further improving the accuracy of waste heat utilization, reducing the ineffective power consumption of the heater 37, and adapting to the heat supply needs of all working conditions.

[0056] As a further embodiment of the present invention, a circulation pump 11 and a check valve 12 are sequentially provided on the water supply main pipe of the water circulation loop along the water flow direction; the check valve 12 is arranged on the water supply main pipe downstream of the circulation pump 11, allowing water to flow only from the circulation pump 11 to each hydrogen storage unit 40, blocking the backflow of pipeline water, and ensuring the stable one-way operation of the water circulation. The number of hydrogen storage units 40 is specifically four; each hydrogen storage unit 40 is equipped with a water valve 14 on its water inlet side; Each hydrogen storage unit 40 is equipped with a hydrogen storage water temperature sensor 28 at its outlet end; the return water temperature after heat exchange of each hydrogen storage unit 40 is collected in real time, and the actual heating temperature inside the hydrogen storage unit 40 is fed back. The solid storage inlet temperature sensor 13 collects the temperature of the hot water before it enters the hydrogen storage unit 40 to determine the hydrogen release and heating conditions; the hydrogen storage outlet water temperature sensor 28 monitors the temperature of a single hydrogen storage unit 40 after heat exchange; the water pressure sensor 39 collects the pressure of the water supply main in real time and sends a fault protection signal to the control unit when there is a water shortage, blockage, or ultra-low pressure; the control unit integrates multiple temperature and pressure data and adjusts the flow ratio of the hydrogen storage three-way valve 32 and the number of hydrogen storage units 40 in operation. Check valve 12 ensures stable one-way operation of the water circuit; independent temperature sensors for multiple branches can accurately monitor the heating status of each hydrogen storage unit 40, and water pressure sensor 39 provides early warning of water circuit faults; independent water circuit control for four hydrogen storage units 40 adapts to the cascade hydrogen supply strategy, balances the hydrogen charging and discharging load of each hydrogen storage unit 40, and extends the service life of the alloy.

[0057] As a further embodiment of the present invention, the hydrogen circuit also includes a hydrogen refueling branch; A hydrogen filter 25 is installed on the hydrogen refueling branch. The inlet of the hydrogen filter 25 is equipped with a hydrogen filling interface 26, and the outlet is branched into multiple hydrogen refueling pipelines. Each hydrogen refueling pipeline is equipped with a one-way valve 22, and each one-way valve 22 is connected to the hydrogen refueling end of each hydrogen storage unit 40. Each hydrogen storage unit 40 is equipped with a hydrogen pressure sensor 44; Hydrogen charging interface 26: External high-pressure hydrogen inlet port, to replenish the system with solid hydrogen storage feedstock hydrogen; Hydrogen filter 25: filters the hydrogen entering the system, removes water vapor and solid impurities, and protects the internal hydrogen storage unit 40 and pipelines; One-way valve 22: allows hydrogen to flow in one direction, only allowing external hydrogen to flow into the hydrogen storage unit 40, and preventing the internal hydrogen of the hydrogen storage unit 40 from flowing out of the hydrogen filling pipeline in the opposite direction; Hydrogen pressure sensor 44: Real-time acquisition of the hydrogen pressure inside the corresponding hydrogen storage unit 40, and feedback to the control unit to determine the hydrogen storage saturation and identify the pressure difference between the hydrogen storage units 40; Hydrogen filling operation: The system closes all water valves 14 and hydrogen valves 18; external hydrogen is introduced into the hydrogen filter 25 through the hydrogen filling interface 26, filtered, and injected into each hydrogen storage unit 40 through the multi-way check valve 22 to complete the adsorption and storage of hydrogen; the control unit monitors the pressure of each tank in real time through each hydrogen pressure sensor 44. When any hydrogen storage unit 40 reaches the rated hydrogen storage pressure, the hydrogen filling of the corresponding branch can be stopped. When the pressure of all hydrogen storage units 40 reaches the standard, the hydrogen filling process ends; the check valve 22 prevents the backflow of high-pressure hydrogen in the tank throughout the process.

[0058] As a further embodiment of the present invention, the hydrogen storage heat exchange branch is provided with an external cooling pipeline, and an inlet quick connector 38 and an outlet quick connector 36 are respectively provided at both ends of the external cooling pipeline; the inlet quick connector 38 is used to connect to external cold water, and the outlet quick connector 36 is used to discharge the cooling water after heat exchange. During the hydrogen filling process, the hydrogen storage unit 40 releases a large amount of adsorption heat. At this time, the external cold water pipeline is connected to the inlet quick connector 38 and the outlet quick connector 36. The external cold water is introduced into the external cooling pipeline to continuously cool the hydrogen storage unit 40, quickly remove the adsorption heat, and ensure the hydrogen filling capacity and hydrogen filling efficiency of the hydrogen storage unit 40. An independent external cooling pipeline is installed with quick-connect connectors 36 at both ends and quick-connect connectors 38 at both ends. External cold water is only connected during the hydrogen refueling and charging stage to force cooling of the hydrogen storage unit 40, quickly removing the heat generated by the adsorption of metal hydrides and preventing the hydrogen storage unit 40 from overheating and reducing its hydrogen storage capacity. The quick-connect structure is easy to install and disassemble, and can be sealed when not in use, without interfering with the normal hydrogen release and heating cycle of the system. This improves the system's hydrogen refueling and cooling function, and enhances the hydrogen refueling speed and the service life of the hydrogen storage unit 40.

[0059] As a further embodiment of the present invention, the hydrogen supply branch is provided with a pressure reducing valve 10, a shut-off valve 8 and a hydrogen supply metal hose 7 in sequence along the airflow direction, and the hydrogen supply branch is also provided with a pressure relief valve 9 in parallel. Pressure reducing valve 10: Stabilizes and reduces the pressure of the high-pressure hydrogen output from the hydrogen storage unit 40, and adjusts the hydrogen pressure to the working pressure adapted to the fuel cell system 6. Shut-off valve 8: Responsible for the on / off of the overall hydrogen supply branch, and can quickly cut off the hydrogen supply in the event of system shutdown or failure. Hydrogen supply metal hose 7: It has the function of shock absorption, buffering and compensating for pipeline installation errors, and delivers depressurized hydrogen to fuel cell system 6; Pressure relief valve 9: It is arranged in parallel on the hydrogen supply branch. When the internal pressure of the hydrogen supply branch exceeds the safety threshold, it will automatically open to relieve pressure, prevent the pipeline from overpressure explosion, and ensure the safety of the hydrogen circuit.

[0060] As a further embodiment of the present invention, the water circulation loop is also provided with a solid storage expansion tank 33 and a main expansion tank 1; The main expansion tank 1 connects the cooling return water pipe between the radiator 3 and the fuel cell system 6 to compensate for the volume change caused by the thermal expansion and contraction of the primary cooling water, balance the pressure of the primary cooling circuit, and accommodate air bubbles in the pipe. The solid storage expansion tank 33 is connected to the outlet water return pipeline of the hydrogen storage unit 40 in the hydrogen storage heat exchange branch; it independently compensates for the volume change of the medium in the secondary side hydrogen storage circulation water circuit. The primary side outlet of the partition heat exchanger 35 is equipped with a heat exchanger outlet water temperature sensor 34. The primary side outlet water temperature of the partition heat exchanger 35 is collected to determine the amount of waste heat released on the primary side, providing a temperature basis for the adjustment of the heat dissipation three-way valve 2 and the hydrogen storage three-way valve 32. The fuel cell system 6 is equipped with a battery outlet water temperature sensor 5 at the outlet water end; it collects the temperature of the cooling medium at the outlet water of the fuel cell system 6 in real time and provides feedback on the heating degree of the fuel cell stack of the fuel cell system 6. A method for coupled control of fuel cell waste heat utilization and hydrogen storage includes the following operating condition control steps: S1. Cold Start Control: When starting in a low-temperature environment, the heater 37 is activated to heat the circulating water, and the hydrogen storage three-way valve 32 is controlled to cut off the waste heat exchange port 73, so that the circulating water flows through the heater 37, the hydrogen storage heat exchange branch, and each hydrogen storage unit 40 in sequence and then flows back to the circulation pump 11 to provide the heat required for hydrogen release to the hydrogen storage unit 40; the hydrogen valve 18 of the corresponding hydrogen storage unit 40 is opened, and the hydrogen is delivered to the fuel cell system 6 after being pressure regulated by the pressure reducing valve 10; S2. Waste heat dynamic distribution control: Real-time monitoring of the operating power of the fuel cell system 6. When operating at low power, the heat exchange three-way valve 4 is controlled to direct all the fuel cell outlet water into the primary side of the indirect heat exchanger 35. At the same time, the hydrogen storage three-way valve 32 is controlled to divert the circulating water to the waste heat exchange branch and the auxiliary heating branch. The waste heat from the fuel cell and the auxiliary heating from the heater 37 together provide heat for the hydrogen storage circuit. When operating at high power, the hydrogen storage three-way valve 32 is controlled to cut off the auxiliary heating branch. All the circulating water absorbs the waste heat from the fuel cell through the indirect heat exchanger 35. At the same time, the heat dissipation three-way valve 2 is controlled to direct the primary side outlet water into the radiator 3 for heat dissipation and then return. S3. Cascaded hydrogen supply control: According to the power demand of the fuel cell system 6, the water valve 14 and hydrogen valve 18 of the corresponding number of hydrogen storage units 40 are opened in sequence to match the hydrogen supply capacity and load power as needed; at the same time, based on the detection value of the hydrogen pressure sensor 44 of each hydrogen storage unit 40, the unit with sufficient hydrogen storage pressure is given priority to be put into operation. S4. Shutdown equalization control: When the fuel cell system 6 is shut down, the heat dissipation three-way valve 2 is first controlled to introduce the primary side water into the radiator 3 to complete the system cooling. Then, the hydrogen valves 18 of all hydrogen storage units 40 are opened to connect the hydrogen circuits of each hydrogen storage unit 40 to achieve hydrogen pressure equalization between units. As a further aspect of the present invention, in step S3, the cascaded hydrogen supply opens the water valve 14 and hydrogen valve 18 corresponding to each hydrogen storage unit 40 in order of increasing power; when the power of the fuel cell system 6 decreases, the water valve 14 and hydrogen valve 18 corresponding to each hydrogen storage unit 40 are closed in reverse order.

Claims

1. A fuel cell waste heat cascade utilization and hydrogen storage coupling system, comprising a fuel cell system (6), at least two hydrogen storage units (40), a water circulation loop, and a hydrogen circulation loop, characterized in that: The water circulation loop includes a waste heat exchange branch, an auxiliary heating branch and a hydrogen storage heat exchange branch; the water circulation loop is equipped with a hydrogen storage three-way valve (32), and the three are connected and separated through the hydrogen storage three-way valve (32); The waste heat exchange branch is equipped with a partition wall heat exchanger (35) and a heat exchange three-way valve (4). The partition wall heat exchanger (35) is equipped with a primary side and a secondary side that are isolated from each other for heat exchange. The outlet of the fuel cell system (6) is connected to the primary side via a heat exchange three-way valve (4), and the outlet water of the primary side flows back to the fuel cell system (6) via a heat dissipation three-way valve (2); the secondary side inlet is connected to a branch outlet of a hydrogen storage three-way valve (32); The inlet of the auxiliary heating branch is connected to another branch outlet of the hydrogen storage three-way valve (32). The outlet of the auxiliary heating branch merges with the secondary side outlet of the partition heat exchanger (35) and is connected to the water supply end of the hydrogen storage heat exchange branch. A heater (37) is provided on the auxiliary heating branch. The hydrogen storage heat exchange branch is equipped with a circulation pump (11), and each hydrogen storage unit (40) is equipped with a water valve (14). The water circuits of each hydrogen storage unit (40) are arranged in parallel, and the effluent flows back to the inlet of the circulation pump (11) to form a closed loop. The hydrogen circuit includes a hydrogen supply branch, and each hydrogen storage unit (40) is provided with a hydrogen valve (18) at its hydrogen supply end. The outlets of each hydrogen valve (18) converge and are connected to the hydrogen supply branch.

2. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that: It also includes a control unit, which is electrically connected to a heat dissipation three-way valve (2), a heat exchange three-way valve (4), a hydrogen storage three-way valve (32), each water valve (14), each hydrogen valve (18), and a heater (37).

3. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that: It also includes the radiator (3); The heat dissipation three-way valve (2) has an inlet and two outlets. Its inlet is connected to the primary side outlet of the partition heat exchanger (35), and the two outlets are respectively connected to the return water port of the fuel cell system (6) and the inlet of the radiator (3). The outlet of the radiator (3) is connected to the return water port of the fuel cell system (6).

4. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The three ports of the hydrogen storage three-way valve (32) are the main water supply inlet (74), the waste heat exchange port (73), and the heating branch port (75). The main water supply inlet (74) is connected to the water from the circulating pump (11), and the waste heat exchange port (73) and the heating branch port (75) are respectively connected to the secondary side inlet of the partition wall heat exchanger (35) and the inlet of the heater (37). The hydrogen storage three-way valve (32) can adjust the on / off state of the waste heat exchange port (73) and the heating branch port (75) and the medium diversion ratio.

5. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The water supply main pipe of the water circulation loop is provided with the circulation pump (11) and check valve (12) in sequence along the water flow direction. The number of hydrogen storage units (40) is specifically four; each of the hydrogen storage units (40) is provided with a water valve (14) on the water inlet side. Each of the hydrogen storage units (40) is equipped with a hydrogen storage outlet water temperature sensor (28) at its outlet end, and the hydrogen storage heat exchange branch is equipped with a solid storage inlet temperature sensor (13) and a water pressure sensor (39) on its water supply side.

6. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The hydrogen circuit also includes a hydrogen refueling branch; A hydrogen filter (25) is provided on the hydrogen refueling branch. The inlet end of the hydrogen filter (25) is provided with a hydrogen filling interface (26), and the outlet end branches into multiple hydrogen refueling pipelines. Each hydrogen refueling pipeline is provided with a one-way valve (22). Each one-way valve (22) is connected to the hydrogen refueling end of each hydrogen storage unit (40). Each of the hydrogen storage units (40) is equipped with a hydrogen pressure sensor (44).

7. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The hydrogen storage heat exchange branch is provided with an external cooling pipeline, and an inlet quick connector (38) and an outlet quick connector (36) are respectively provided at both ends of the external cooling pipeline; the inlet quick connector (38) is used to connect to external cold water, and the outlet quick connector (36) is used to discharge the cooling water after heat exchange.

8. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The hydrogen supply branch is provided with a pressure reducing valve (10), a shut-off valve (8) and a hydrogen supply metal hose (7) in sequence along the airflow direction. The hydrogen supply branch is also provided with a pressure relief valve (9) in parallel.

9. The fuel cell waste heat cascade utilization and hydrogen storage coupling system according to claim 1, characterized in that, The water circulation loop is also equipped with a solid storage expansion tank (33) and a main expansion tank (1). The main expansion tank (1) is connected to the cooling return water pipe between the radiator (3) and the fuel cell system (6), and the solid storage expansion tank (33) is connected to the outlet water return pipe of the hydrogen storage unit (40) in the hydrogen storage heat exchange branch. The primary outlet of the indirect heat exchanger (35) is equipped with a heat exchanger outlet water temperature sensor (34), and the outlet of the fuel cell system (6) is equipped with a battery outlet water temperature sensor (5).

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