Vehicle-mounted liquid hydrogen storage and supply system and control method thereof

Abstract

The invention belongs to the technical field of hydrogen energy and automobile engineering, and particularly relates to a vehicle-mounted liquid hydrogen storage and supply system and a control method thereof. The liquid adding pipeline is communicated with the vehicle-mounted liquid hydrogen tank; the output pipeline is communicated with the vehicle-mounted liquid hydrogen tank; the safety bleeding pipeline is communicated with the vehicle-mounted liquid hydrogen tank; the detection assembly comprises a liquid level detection unit and a pressure detection unit, and the liquid level detection unit and the pressure detection unit are respectively matched with the vehicle-mounted liquid hydrogen gas tank and are used for monitoring liquid level and pressure parameters in the tank; and the control module is electrically connected with the output pipeline, the safe bleeding pipeline and the detection assembly. Through deep fusion of structural design and control logic, the coupling restriction problem of the heat insulation performance, structural reliability and dynamic hydrogen supply control of the vehicle-mounted liquid hydrogen storage and supply system is solved, multi-target collaborative optimization is achieved, and the system is suitable for a heavy-load long-endurance fuel cell commercial vehicle.

Description

Technical Field

[0001] This invention relates to the fields of hydrogen energy and automotive engineering technology, and more specifically, to an on-board liquid hydrogen storage and supply system and its control method. Background Technology

[0002] Against the backdrop of profound adjustments to the global energy structure and the accelerated implementation of dual-carbon goals, hydrogen fuel cell vehicles, as a key pathway to achieving zero carbon emissions in the transportation sector, are gradually moving from demonstration applications to large-scale promotion. In this process, on-board hydrogen storage technology, as a core component determining the overall vehicle performance, safety, and economy, directly impacts the market competitiveness of hydrogen fuel cell vehicles in demanding application scenarios such as heavy-duty and long-distance travel. Currently, mainstream commercial hydrogen fuel cell vehicles generally employ 35 MPa or 70 MPa high-pressure gaseous hydrogen storage systems. This technology, relying on relatively mature hydrogen refueling station infrastructure, has demonstrated certain engineering feasibility in early demonstration operations. Its basic principle involves using high-strength composite materials to wrap a pressure vessel, compressing gaseous hydrogen at extremely high pressure at room temperature, thereby achieving hydrogen storage within a limited space. This solution effectively alleviated the initial predicament of "having a vehicle but no hydrogen" or "having hydrogen but difficulty in storage" for hydrogen-powered vehicles during a specific historical period, providing an important platform for collaborative verification across the industry chain.

[0003] However, as applications evolve towards heavier and longer-distance applications, the inherent limitations of high-pressure gaseous hydrogen storage systems at the physical level are becoming increasingly apparent. Their volumetric hydrogen storage density is only about 40 g / L, and their mass hydrogen storage density is less than 5%, resulting in a large tank size and significant weight for the same range requirements. This not only occupies valuable chassis space but also significantly increases the vehicle's curb weight due to structural redundancy caused by high pressure, creating a structural contradiction: "more storage means shorter range, and longer range means more space." Especially for heavy-duty transport vehicles with a gross vehicle weight exceeding 25 tons, their actual range generally struggles to exceed 500 kilometers, severely restricting commercial operational efficiency. Against this backdrop, cryogenic liquid hydrogen storage and supply systems, with their significant advantages of a theoretical volumetric hydrogen storage density exceeding 70 g / L and a mass hydrogen storage density approaching 10%, are considered a strategic technological direction for overcoming these bottlenecks. Liquid hydrogen is stored in liquid form at -253°C. Essentially, it achieves a high degree of energy concentration through the latent heat of phase change, thus carrying nearly twice the effective fuel of high-pressure gaseous hydrogen in the same volume, providing the physical basis for a thousand-kilometer range.

[0004] However, the migration of liquid hydrogen storage and supply systems from static industrial scenarios to dynamic vehicle environments has exposed a series of deep-seated technical contradictions. Among these, the most critical and less obvious is the irreconcilable coupling and constraint between thermal insulation performance, structural reliability, and dynamic hydrogen supply control. Specifically, achieving a low evaporation rate requires a high-vacuum, multi-layered thermal insulation structure, which is extremely sensitive to mechanical integrity. Under complex road conditions, vehicles continuously endure high-frequency vibrations and impact loads, easily leading to fretting wear of the interlayer support structure, partial collapse of the multi-layered reflectors, or vacuum deterioration. This results in irreversible degradation of thermal insulation performance, causing the daily evaporation rate to exceed the limit, leading to continuous fuel loss and even loss of sustainment time. Furthermore, even if the thermal insulation structure is maintained, the liquid hydrogen system requires frequent pressurization and depressurization operations during hydrogen supply to match fuel cell power fluctuations. This process itself disrupts the thermal balance and exacerbates evaporation. If the control strategy is crude, relying solely on a single pressure threshold to switch hydrogen supply modes, hydrogen supply lag or overshoot can easily occur under sudden load changes, forcing the system to frequently start and stop the booster circuit. This not only reduces energy efficiency but also accelerates insulation fatigue failure due to repeated thermal stress cycles. Furthermore, existing safety mechanisms mostly employ passive overpressure relief, lacking proactive diagnosis and graded response capabilities for early anomalies such as leaks and sensor drift. In the event of vacuum failure or valve jamming, the system often directly enters an emergency discharge state, wasting valuable fuel and potentially causing localized hydrogen accumulation risks due to concentrated exhaust. Fundamentally, the design logic of existing onboard liquid hydrogen systems still follows a static container mindset, failing to incorporate "vehicle dynamic operation—thermodynamic stability—hydrogen supply accuracy—structural vibration resistance" into a unified closed-loop control framework. This results in subsystems hindering each other and making collaborative optimization difficult when dealing with real-world road conditions.

[0005] Therefore, how to construct an on-board liquid hydrogen storage and supply system that integrates high thermal stability, strong vibration adaptability, high-precision dynamic hydrogen supply control and intelligent safety protection, and achieve multi-objective collaborative optimization through deeply integrated control methods, has become a key technical challenge to break through the bottleneck of commercial application of liquid hydrogen heavy trucks and truly unleash their high hydrogen storage density potential. Summary of the Invention

[0006] This invention provides an on-board liquid hydrogen storage and supply system and its control method, aiming to solve the coupling constraint problem among thermal insulation performance, structural reliability and dynamic hydrogen supply control in the prior art.

[0007] This invention provides an on-board liquid hydrogen storage and supply system, comprising: an on-board liquid hydrogen tank for storing liquid hydrogen; a filling pipeline connected to the on-board liquid hydrogen tank for adding liquid hydrogen to the tank; an output pipeline connected to the on-board liquid hydrogen tank for delivering liquid hydrogen or hydrogen gas to a hydrogen-consuming end; a safety venting pipeline connected to the on-board liquid hydrogen tank for overpressure venting; a detection component including a level detection unit and a pressure detection unit, which respectively cooperate with the on-board liquid hydrogen tank to monitor the liquid level and pressure parameters inside the tank; and a control module electrically connected to the output pipeline, the safety venting pipeline, and the detection component for executing hydrogen supply and safety control logic.

[0008] Preferably, the liquid filling pipeline includes an inlet connector, an inlet check valve, and an inlet pipe connected in sequence. The inlet pipe is connected to the liquid phase area inside the vehicle-mounted liquid hydrogen tank, and the inlet check valve is unidirectionally open along the liquid hydrogen filling direction.

[0009] Preferably, the output pipeline includes a liquid phase output branch and a pressurization branch; the liquid phase output branch is sequentially provided with a first manual shut-off valve, a liquid outlet solenoid valve, a hydrogen supply solenoid valve, a flow valve, a water bath vaporizer, a compressor, and a buffer tank along the liquid hydrogen delivery direction; the liquid outlet solenoid valve is connected to the liquid phase area inside the vehicle-mounted liquid hydrogen tank, and the buffer tank is connected to the hydrogen-using end through a gas supply port; the pressurization branch includes a gas phase pipe, a second manual shut-off valve, a booster, a pressurization valve, and an economy valve; the gas phase pipe is connected to the gas phase area inside the vehicle-mounted liquid hydrogen tank, and the gas phase pipe flows back to the vehicle-mounted liquid hydrogen tank sequentially through the second manual shut-off valve, the booster, the pressurization valve, and the economy valve.

[0010] Preferably, the design pressure of the on-board liquid hydrogen tank is 2.5 MPa; the control module is configured to: open the liquid outlet solenoid valve and the pressure boosting valve and close the hydrogen supply solenoid valve when the pressure inside the on-board liquid hydrogen tank is lower than 64% of its design pressure; and close the liquid outlet solenoid valve and open the economy valve and the hydrogen supply solenoid valve when the pressure inside the on-board liquid hydrogen tank is higher than 80% of its design pressure.

[0011] Preferably, the control module is further configured to: adjust the displacement of the compressor using a PID algorithm based on the detection signal from the second pressure transmitter on the buffer tank, so as to maintain a constant output pressure of the buffer tank.

[0012] Preferably, the safety venting pipeline includes a safety valve group and a manual venting branch connected in parallel; the safety valve group includes a third manual shut-off valve, a first safety valve, a fourth manual shut-off valve, and a second safety valve, the third manual shut-off valve and the first safety valve connected in series to form a first safety branch, the fourth manual shut-off valve and the second safety valve connected in series to form a second safety branch, and the first safety branch and the second safety branch connected in parallel to communicate with the gas phase area of ​​the vehicle-mounted liquid hydrogen tank; the manual venting branch includes a venting valve and a venting check valve connected in sequence, the venting valve communicating with the gas phase area of ​​the vehicle-mounted liquid hydrogen tank, and the venting check valve venting gas outward through the vent port.

[0013] Preferably, the opening pressures of the first safety valve and the second safety valve increase sequentially, and both are less than the maximum working pressure of the on-board liquid hydrogen tank.

[0014] Preferably, the liquid level detection unit is a capacitive liquid level gauge, including a liquid level probe that extends into the vehicle-mounted liquid hydrogen tank; the detection assembly also includes a temperature sensor, which is located in the lower part of the vehicle-mounted liquid hydrogen tank.

[0015] Preferably, the control module is configured to: calculate the liquid hydrogen volume based on the signal from the level gauge probe, and query a preset liquid hydrogen property table based on the signal from the temperature sensor to obtain the real-time density, thereby calculating the real-time hydrogen capacity. Specifically, the control module is electrically connected to the liquid outlet solenoid valve, liquid consumption solenoid valve, and compressor in the output pipeline, the vent valve and safety valve in the safety vent pipeline, and the level detection unit, pressure detection unit, and temperature sensor in the detection assembly.

[0016] This invention also provides a control method for an on-board liquid hydrogen storage and supply system, used for controlling the aforementioned on-board liquid hydrogen storage and supply system, comprising the following steps: communicating with a hydrogen refueling machine via a CAN bus to receive refueling commands and feedback initial state parameters; during hydrogen supply, real-time acquisition of tank pressure, buffer tank pressure, liquid level, and temperature data; switching between boost mode and economic hydrogen supply mode based on a comparison of tank pressure with a preset threshold; dynamically adjusting compressor displacement using a PID algorithm based on the deviation between buffer tank pressure and target pressure to achieve constant pressure hydrogen supply; executing corresponding valve actions for emergency handling when overpressure, leakage, or sensor failure is detected; the degraded operation refers to: under non-fatal fault conditions, closing the liquid phase output branch and only opening the gas phase output path to maintain the fuel cell system at minimum power operation, while illuminating the dashboard malfunction indicator light.

[0017] This invention achieves multi-objective collaborative optimization of the liquid hydrogen storage and supply system under dynamic vehicle conditions through the deep integration of the above-mentioned structural design and control logic: the high-vacuum multi-layer insulation sandwich combined with the vibration-resistant support structure ensures that the daily evaporation rate is stably controlled within 4.0%; the precise switching of the booster branch and the economy valve, combined with the closed-loop control of the variable displacement compressor, enables dynamic hydrogen supply with a wide range of 0-100g / s and a pressure accuracy of ±0.5%; multi-level safety mechanisms and fault degradation strategies ensure that the system can maintain basic functions or safely shut down under various abnormal operating conditions; the rear-mounted single-tank arrangement takes into account both space efficiency and structural reliability, with the entire system achieving a volumetric hydrogen storage density of over 70g / L, a mass hydrogen storage density of not less than 10wt%, and a single tank hydrogen capacity of ≥85kg, supporting a driving range of over 1000 kilometers for heavy-duty vehicles, and a refueling rate of 10-15kg / min, which is significantly better than the 35MPa high-pressure gaseous hydrogen storage system. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the vehicle-mounted liquid hydrogen storage and supply system described in this invention.

[0019] Figure 2 This is the core control logic of the control module of the present invention.

[0020] Figure 3 This is a flowchart illustrating the control logic of the pressure closed loop of the on-board liquid hydrogen storage and supply system described in this invention.

[0021] In the above attached diagram, the component numbers are as follows:

[0022] 1. Onboard liquid hydrogen tank; 2. Level gauge probe; 3. Signal box; 4. Level gauge display; 5. Inlet pipe; 6. Gas phase pipe; 7. First safety valve; 8. Second safety valve; 9. First pressure transmitter; 10. Vent valve; 11. Vent check valve; 12. Inlet check valve; 13. First manual shut-off valve; 14. Inlet connector; 15. Second manual shut-off valve; 16. Outlet solenoid valve; 17. Hydrogen supply solenoid valve; 18. Overflow valve; 19. Water bath vaporizer; 20. Compressor; 21. Buffer tank; 22. Second pressure transmitter; 23. Booster; 24. Booster valve; 25. Economy valve; 26. Third manual shut-off valve; 27. Fourth manual shut-off valve. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, but these are not intended to limit the scope of the invention and are merely illustrative. It should be noted that, unless otherwise specified, the embodiments and technical features described in this application can be combined with each other. Unless otherwise indicated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials, reagents, etc., used in the following embodiments are commercially available.

[0024] This invention provides an on-board liquid hydrogen storage and supply system and its control method, the overall structure of which is as follows: Figure 1 As shown in the accompanying drawings, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to ensure that those skilled in the art can completely and accurately reproduce the technical solution of the present invention based on this specification.

[0025] The core component of the vehicle-mounted liquid hydrogen storage and supply system is the vehicle-mounted liquid hydrogen tank 1. This tank adopts a double-layer vacuum insulation structure. The inner liner is integrally spun from austenitic stainless steel S30408, with a wall thickness of 6.5mm and an effective volume of 1215L. The design pressure is 2.5MPa, and the design temperature is -259℃ to 50℃. The outer container is manufactured by rolling and welding high-strength low-alloy steel Q345R, with a wall thickness of 8mm, an outer diameter of 1200mm, and a length of 2800mm. A ring-shaped high-vacuum multi-layer insulation interlayer is formed between the inner liner and the outer container. The interlayer is evacuated to an absolute pressure not exceeding 5×10⁻⁶. -3 Pa is filled with a reflective screen assembly consisting of alternating layers of fiberglass cloth and aluminum foil, with a total of 48 layers. The aluminum foil is 6 μm thick and the fiberglass cloth has a surface density of 80 g / m³. 2 Polyester nonwoven fabric is used as the spacer between the layers to suppress radiative heat transfer and maintain structural stability. The sandwich support structure consists of 12 axially distributed GFRP (glass fiber reinforced plastic) composite material pillars, evenly distributed along the circumference. Each pillar is 2750mm long, 30mm in diameter, and has a compressive strength of not less than 350MPa. Both ends are fixed to the outer wall of the inner liner and the inner wall of the outer container respectively using laser welding. The matrix resin of the GFRP pillars is a high-damping epoxy resin system, with a loss factor tanδ of not less than 0.08 at 20℃ and 10Hz. Vibration energy is converted into heat energy through the material's own internal friction mechanism. The welded areas are inspected by X-ray flaw detection, and the welds are free of defects such as cracks, lack of fusion, or porosity, ensuring the integrity of the rigid connection. The two work together to effectively suppress fretting wear generated by the vehicle under high-frequency vibration conditions, ensuring the long-term sealing of the high-vacuum sandwich layer.

[0026] The liquid hydrogen filling pipeline of the vehicle-mounted liquid hydrogen tank 1 includes an inlet connector 14, an inlet check valve 12, and an inlet pipe 5 connected in sequence. The inlet connector 14 adopts an ISO 17268 standard quick-connect interface, with a nominal diameter of DN25 and a rated working pressure of 4.0MPa. The inlet check valve 12 is a normally closed straight-through structure. The valve core sealing pair is made of polytetrafluoroethylene (PTFE) and hardened stainless steel. The opening pressure difference is not greater than 0.05MPa, and there is no visible leakage under the reverse sealing pressure of 4.0MPa. The response time is less than 200ms. The inlet pipe 5 is an S30408 ​​stainless steel pipe with an inner diameter of Φ20mm. One end is welded to the top end cap of the inner tank, and the other end is connected to 150mm above the bottom of the inner tank to ensure that liquid hydrogen directly enters the liquid phase area during the filling process, reducing cavitation and splashing.

[0027] The output pipeline is divided into a liquid phase output branch and a pressurization branch. The liquid phase output branch is led out from the bottom of the inner tank and is connected in sequence to the first manual shut-off valve 13, the liquid outlet solenoid valve 16, the hydrogen supply solenoid valve 17, the overflow valve 18, the water bath vaporizer 19, the compressor 20, and the buffer tank 21. The liquid outlet solenoid valve 16 is a cryogenic normally closed solenoid valve with a nominal diameter of DN20, an operating temperature range of -270℃ to +80℃, a maximum operating pressure of 4.0MPa, and an opening response time ≤80ms. The hydrogen supply solenoid valve 17 has the same structural parameters as the liquid outlet solenoid valve 16 and is used to open the gas phase path in the economic hydrogen supply mode. The overflow valve 18 is a mechanical flow limiting device that automatically closes when the liquid hydrogen flow rate exceeds 110g / s to prevent pipeline overload. The water bath vaporizer 19 is a shell-and-tube heat exchanger, with engine coolant (ethylene glycol aqueous solution, inlet temperature 85℃, flow rate 15L / min) flowing through the shell side and liquid hydrogen flowing through the tube side, with a heat exchange area of ​​1.5m². 2 The vaporization capacity is 120g / s, and the outlet hydrogen temperature is not lower than -40℃. The compressor 20 is a variable displacement scroll compressor with a displacement adjustment range of 0~120L / min (standard state). The drive motor is a permanent magnet synchronous motor with a rated power of 5.5kW and a rated speed of 3000rpm. It receives control module commands through the CAN bus to achieve stepless displacement adjustment. The buffer tank 21 has a volume of 20L and is made of 6061-T6 aluminum alloy. It is equipped with a rectifier plate inside to stabilize the airflow. Its outlet is connected to the fuel cell system through the gas supply port. The gas supply pressure of the buffer tank is set to 1.3MPa.

[0028] The booster branch extends from the vapor phase area at the top of the inner tank and includes a vapor phase pipe 6, a second manual shut-off valve 15, a booster 23, a booster valve 24, and an economy valve 25. The vapor phase pipe 6 is an S30408 ​​stainless steel pipe with an inner diameter of Φ15mm; the second manual shut-off valve 15 is a bellows-sealed shut-off valve with a nominal pressure of PN40; the booster 23 is a plate-fin heat exchanger, with low-pressure hydrogen from the vapor phase pipe 6 on the cold side and engine coolant (inlet temperature 85℃, flow rate 8L / min) on the hot side, with a heat exchange area of ​​1.35m².2 The measured heat transfer coefficient is 825 W / (m²). 2 ·K), which can heat hydrogen to above -196℃, improving reinjection efficiency; both booster valve 24 and economy valve 25 are pilot-operated proportional solenoid valves, with valve body material of 316L stainless steel, operating temperature of -270℃ to +100℃, response time ≤90ms, flow adjustment range of 0~50g / s, control signal of 0~10V analog quantity, and linearity error ≤±1.5%.

[0029] The safety venting pipeline includes a safety valve assembly and a manual venting branch connected in parallel. The safety valve assembly consists of two independent branches: the first safety branch is formed by the third manual shut-off valve 26 and the first safety valve 7 connected in series, and the second safety branch is formed by the fourth manual shut-off valve 27 and the second safety valve 8 connected in series. The two branches are connected in parallel and then connected to the gas phase space of the inner liner. The third manual shut-off valve 26 and the fourth manual shut-off valve 27 are both full-bore bellows shut-off valves with a nominal diameter of DN25. The opening pressure of the first safety valve 7 is set to 2.2MPa, and the opening pressure of the second safety valve 8 is set to 2.4MPa. Both are full-lift spring safety valves with a discharge port diameter of DN20. The measured action delay times are 0.25s and 0.28s, respectively. The discharge capacity is calculated to meet the maximum discharge requirements in GB / T 24159-2022 (corresponding to a maximum evaporation rate of 12kg / h under fire conditions). The manual venting branch is connected in sequence to the venting valve 10 and the venting check valve 11. The venting valve 10 is a ball valve with an operating torque ≤10N·m. The venting check valve 11 prevents backflow of external air, and its outlet is led to the high-level venting port on the roof through a pipeline, at a height ≥2.5m above the ground.

[0030] The detection components include a level detection unit, a pressure detection unit, and a temperature sensor. The level detection unit is a capacitive level gauge, with its level gauge probe 2 employing a coaxial double-layer structure. The inner electrode is a 3mm diameter solid 316L stainless steel rod, and the outer electrode is an 8mm diameter seamless 316L stainless steel tube. A 0.1mm thick polyimide film serves as the insulating layer between the two. The probe has a total length of 2600mm, and its effective measuring section covers 10% to 95% of the inner tank height (i.e., 260mm to 2470mm), with a resolution of 1mm and a measurement accuracy of ±2mm. The pressure detection unit includes a first pressure transmitter. The first pressure transmitter 9 is installed in the gas phase space at the top of the vehicle-mounted liquid hydrogen tank 1, with a measurement range of 0 to 4 MPa, an accuracy of ±0.3%FS, and a sampling frequency of 100 Hz. The second pressure transmitter 22 is installed at the outlet of the buffer tank 21, with parameters consistent with those of the first pressure transmitter 9. The temperature sensor is a Pt100 platinum resistance thermometer, encapsulated in a Φ6mm×500mm 316L stainless steel sheath, installed in the lower middle liquid phase region of the inner tank, with a temperature measurement range of -260℃ to 50℃.

[0031] The control module is an embedded controller based on an ARM Cortex-M7 core, with a main frequency of 480MHz, equipped with 128MB of non-volatile memory, and running a real-time operating system (RTOS). The control module connects to various solenoid valves, shut-off valve actuators, and sensors via hardwired connections, and communicates with the vehicle control unit (VCU) and hydrogen refueling machine via a CAN bus. Internally, the control module stores a pre-calibrated inner tank geometry model data table, recording the liquid level height h (in mm) and the corresponding effective volume V(h) (in m³). 3 The mapping relationship between the two data points was obtained by fitting the data after a 3D laser scan of the inner liner, with an interpolation error of less than 0.1%. Simultaneously, a liquid hydrogen property table generated from the NISTREFPROP 10.0 database is stored, including temperature T (unit: K) and density ρ(T) (unit: kg / m³). 3 The corresponding relationship is as follows: temperature interval 1K, density value continuously covers the range of 13.8K to 33.2K. The control module synchronously reads the temperature sensor signal within each liquid level sampling cycle (cycle is 100ms), calculates the current density using linear interpolation, and then uses the formula: , calculate hydrogen capacity m (unit: kg) in real time.

[0032] Figure 2This is a flowchart of the core control logic of the control module. The core logic and signal interaction of the control module are explained as follows: After power-on, the control module first completes a sensor self-test. If an abnormality is detected, a sensor fault alarm is triggered, and the system enters a degraded operation mode, only activating the gas phase hydrogen supply path to maintain the fuel cell at minimum power until the fault is repaired and normal operation resumes. If the self-test is normal, the system enters standby mode, waiting for refueling or hydrogen supply commands. Upon receiving a refueling command, the refueling process control is executed, and the system returns to standby mode upon completion. Upon receiving a hydrogen supply command, the system enters the hydrogen supply process, monitoring the tank pressure, liquid level, and temperature parameters in real time: When the tank pressure is below 1.6 MPa, the liquid outlet solenoid valve and the pressure boosting valve are opened, and the gas supply solenoid valve is closed, putting the system into pressure boosting mode; when the pressure is between 1.6 MPa and 2.0 MPa, the current operating mode is maintained; when the pressure is above 2.0 MPa, the liquid outlet solenoid valve is closed, and the economy valve and the gas supply solenoid valve are opened, switching to the economy hydrogen supply mode. If overpressure or leakage is detected during hydrogen supply, the emergency response procedure is immediately initiated: In case of overpressure, the safety valve assembly is opened to release pressure. If the pressure continues to rise above 2.4 MPa, the manual venting branch is further opened, and an emergency shutdown command is sent to the vehicle controller. In case of leakage, all liquid-gas passage valves are immediately closed, the venting valve is opened for controlled discharge, an audible and visual alarm is triggered, and an emergency shutdown command is sent. The sensor and control module exchange data with a 100ms cycle. The control module performs range verification and abrupt change verification on the sampled data. If an anomaly is detected, a fault determination is triggered. The control module controls the opening of the solenoid valve and the compressor speed through PWM signals or CAN bus commands. The actuator provides real-time feedback on status information such as switch position signals and operating current. The control module communicates with the vehicle controller using the SAE J1939 protocol to transmit data such as hydrogen supply status, fault codes, and emergency commands. In case of fault degradation, a command to maintain minimum power operation is sent; in case of emergency response, an emergency shutdown command is sent.

[0033] The control module executes the following control logic: When the pressure inside the on-board liquid hydrogen tank 1 is lower than 1.6 MPa (i.e., 64% of the design pressure of 2.5 MPa), the liquid outlet solenoid valve 16 and the booster valve 24 are opened, and the hydrogen supply solenoid valve 17 is closed. The system enters the booster mode, and liquid hydrogen is partially reinjected into the gas phase space after vaporization through the liquid phase output branch, increasing the tank pressure. When the pressure inside the tank is higher than 2.0 MPa (i.e., 80% of the design pressure of 2.5 MPa), the liquid outlet solenoid valve 16 is closed, and the economy valve 25 and the hydrogen supply solenoid valve 17 are opened. The system switches to the economy hydrogen supply mode, directly utilizing gas phase hydrogen for energy supply, avoiding unnecessary liquid hydrogen vaporization losses. The opening degree of the booster valve 24 and the economy valve 25 is dynamically adjusted by the control module according to the pressure deviation to ensure a smooth pressure transition.

[0034] During hydrogen supply, the control module continuously acquires signals from the second pressure transmitter 22 and adjusts the displacement of the compressor 20 based on a PID algorithm. The PID control cycle is 10ms, the proportional coefficient Kp=1.2, the integral time Ti=0.8s, the derivative time Td=0.1s, and the control output is limited to 0~10V, corresponding to a compressor speed of 0~3000rpm. The pressure closed-loop control logic is as follows: Figure 3 As shown, when the power demand of the fuel cell suddenly changes (such as jumping from 30kW to 100kW) causing the pressure of the buffer tank 21 to drop by 0.08MPa instantaneously, the control module completes the compressor speed adjustment within 480ms, so that the pressure is restored to the range of 1.3MPa±0.0065MPa. The hydrogen supply flow rate is continuously adjustable in the range of 0 to 100g / s, and the measured flow fluctuation value is ±4.2%, which meets the stringent requirements of the fuel cell system for hydrogen supply stability.

[0035] During the refueling process, the control module establishes communication with the hydrogen dispenser via a CAN bus. The physical layer conforms to the ISO 11898-2 standard with a baud rate of 500kbps, and the application layer protocol complies with SAE J1939. Interactive parameters include cylinder pressure, cylinder level, hydrogen supply pressure, hydrogen supply flow rate, hydrogen temperature, and hydrogen concentration. The hydrogen concentration is detected by catalytic combustion hydrogen sensors installed at the flange joints of each pipeline, with a range of 0–4%vol and a response time ≤2.8s. Before refueling begins, the onboard system sends the initial liquid level (e.g., 30%), pressure (e.g., 1.8 MPa), and temperature (e.g., 20.5 K) to the hydrogen refueling machine. Based on this, the hydrogen refueling machine calculates the maximum refueling capacity (considering the 95% fill rate limit). During refueling, the onboard system reports the liquid level change rate to the hydrogen refueling machine every 100 ms. When the liquid level reaches 95%, it immediately sends a "refueling complete" signal, and the hydrogen refueling machine closes the hydrogen refueling nozzle valve, terminating the refueling process. The entire refueling rate reaches 12.3 kg / min, and a single refueling of 85.2 kg of liquid hydrogen takes 6 minutes and 55 seconds.

[0036] The safety monitoring mechanism is executed in real time by the control module. The control module continuously compares the readings of the first pressure transmitter 9 and the second pressure transmitter 22. If the difference exceeds 0.1 MPa and persists for 1.2 seconds, it is determined that the output pipeline is blocked or the sensor is faulty, triggering a level one alarm. The liquid outlet solenoid valve 16 is closed, the economy valve 25 is opened, and the system switches to gas phase hydrogen supply mode to maintain basic hydrogen supply capacity. If any hydrogen sensor detects a hydrogen concentration exceeding 1% vol for 2.1 seconds, it is determined to be a leak, and the control module immediately closes all solenoid valves, including the liquid outlet solenoid valve 16, the hydrogen supply solenoid valve 17, and the pressurization valve. Valve 24 and economy valve 25 open vent valve 10 for controlled emission, and at the same time send an "emergency stop" command to the vehicle controller via CAN bus to cut off the fuel cell power supply; if the liquid level gauge probe 2 signal is lost (such as disconnection or short circuit), the control module activates the backup strategy: based on the above effective liquid level value, combined with the preset daily evaporation rate model (a daily evaporation rate of 4.0% corresponds to a static evaporation rate of about 3.4 kg / h) to estimate the hydrogen capacity, maintain the system in degraded operation, and illuminate the red fault light on the instrument panel to prompt the driver to drive to the nearest repair station.

[0037] The vehicle-mounted liquid hydrogen tank 1 adopts a rear-mounted single-tank arrangement, installed between the longitudinal beams of the frame behind the cab, and fixed by a three-point rigid bracket. The bracket is forged from Q690D high-strength steel with a yield strength ≥690MPa. Finite element analysis shows that under Class C road surface excitation as specified in ISO 8608 (frequency range 1~50Hz, acceleration power spectral density 0.01m), it meets the requirements. 2 / s 3 The maximum acceleration response at the bottom of the gas cylinder is 13.7g, far below the design threshold of 15g, ensuring that the high-vacuum sandwich structure suffers no structural damage throughout its entire lifespan. The cylinder's exterior is covered by an integral aluminum alloy protective ring, made of 5052-H32 material, 3mm thick, covering all cylinder valves, including the inlet connector, vent valve, safety valve, and pipeline interfaces. The protective ring is connected to the cylinder's outer wall via M8 stainless steel bolts with a bolt spacing ≤150mm, effectively resisting stone impacts of 50mm diameter at a speed of 15m / s.

[0038] To verify the technical effects of the present invention, the following embodiments and comparative tests were conducted.

[0039] Example 1

[0040] Using the complete system configuration described above, a real-vehicle test was conducted on a heavy-duty fuel cell tractor. The ambient temperature was 25℃, the initial liquid level was 95%, and the initial pressure was 1.9MPa. The vehicle operated under NEDC cycle conditions, continuously supplying hydrogen for 8 hours, and the daily evaporation rate, hydrogen supply pressure stability, and system reliability were recorded.

[0041] Comparative Example 1

[0042] A traditional high-pressure gaseous hydrogen storage system was used, employing a 35MPa Type III cylinder with a hydrogen storage density of 5.2wt% by mass and 40g / L by volume. Example 1 and Comparative Example 1 were compared and tested on the same vehicle platform under the same operating conditions.

[0043] The test results are shown in Table 1:

[0044] Table 1: Comparison of Key Performance Indicators between On-board Liquid Hydrogen Storage and Supply System and Traditional High-Pressure Gaseous Hydrogen Storage System

[0045]

[0046] Tests show that this invention significantly outperforms traditional high-pressure gaseous systems in terms of hydrogen storage density, refueling efficiency, hydrogen supply accuracy, and endurance. Especially during dynamic hydrogen supply, thanks to the intelligent switching between the booster branch and the economy valve, the rapid response of the variable displacement compressor, and high-precision PID control, the system achieves highly stable hydrogen supply over a wide flow range. The safety mechanisms correctly triggered corresponding contingency plans in both simulated leakage (manual opening of a small leakage valve) and sensor failure (removal of the level probe) scenarios, and no safety incidents occurred.

[0047] In summary, this invention successfully resolves the coupling contradiction between insulation performance, structural reliability, and dynamic control in on-board liquid hydrogen storage and supply systems by organically integrating a high-vacuum multi-layer insulation structure, vibration-resistant support design, dual-mode hydrogen supply pipeline, closed-loop pressure control, and multi-level safety strategies. It achieves a high-efficiency, high-safety, and high-reliability integrated solution, suitable for engineering applications in heavy-duty, long-range fuel cell commercial vehicles.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, and obtain equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A vehicle-mounted liquid hydrogen storage and supply system, characterized in that, include: Vehicle-mounted liquid hydrogen tank (1) for storing liquid hydrogen; A liquid filling pipeline is connected to the vehicle-mounted liquid hydrogen tank (1) and is used to add liquid hydrogen to the vehicle-mounted liquid hydrogen tank (1); The output pipeline is connected to the vehicle-mounted liquid hydrogen tank (1) and is used to deliver liquid hydrogen or hydrogen to the hydrogen-using end. A safety venting pipeline is connected to the vehicle-mounted liquid hydrogen tank (1) for overpressure venting; The detection component includes a liquid level detection unit and a pressure detection unit, which are respectively used in conjunction with the vehicle-mounted liquid hydrogen tank (1) to monitor the liquid level and pressure parameters inside the tank; The control module is electrically connected to the output pipeline, the safety venting pipeline, and the detection components, and is used to execute hydrogen supply and safety control logic.

2. The on-board liquid hydrogen storage and supply system according to claim 1, characterized in that, The liquid filling pipeline includes an inlet connector (14), an inlet check valve (12), and an inlet pipe (5) connected in sequence. The inlet pipe (5) is connected to the vehicle-mounted liquid hydrogen tank (1), and the inlet check valve (12) is unidirectionally open in the direction of liquid hydrogen filling.

3. The on-board liquid hydrogen storage and supply system according to claim 1, characterized in that, The output pipeline includes a liquid phase output branch and a pressurization branch; The liquid phase output branch is provided with a first manual shut-off valve (13), a liquid outlet solenoid valve (16), a hydrogen supply solenoid valve (17), an overflow valve (18), a water bath vaporizer (19), a compressor (20), and a buffer tank (21) in sequence along the liquid hydrogen delivery direction. The liquid outlet solenoid valve (16) is connected to the liquid phase area inside the vehicle-mounted liquid hydrogen tank (1), and the buffer tank (21) is connected to the hydrogen supply end through the gas supply port. The pressurization branch includes a gas phase pipe (6), a second manual shut-off valve (15), a booster (23), a booster valve (24), and an economy valve (25). The gas phase pipe (6) is connected to the gas phase area inside the vehicle-mounted liquid hydrogen tank (1). The gas phase pipe (6) flows back to the vehicle-mounted liquid hydrogen tank (1) in sequence through the second manual shut-off valve (15), the booster (23), the booster valve (24), and the economy valve (25).

4. The on-board liquid hydrogen storage and supply system according to claim 3, characterized in that, The design pressure of the vehicle-mounted liquid hydrogen tank is 2.5 MPa; the control module is configured to: when the pressure inside the vehicle-mounted liquid hydrogen tank (1) is lower than 64% of its design pressure, open the liquid outlet solenoid valve (16) and the pressure boosting valve (24), and close the hydrogen supply solenoid valve (17); when the pressure inside the vehicle-mounted liquid hydrogen tank (1) is higher than 80% of its design pressure, close the liquid outlet solenoid valve (16), and open the economy valve (25) and the hydrogen supply solenoid valve (17).

5. The on-board liquid hydrogen storage and supply system according to claim 3, characterized in that, The buffer tank (21) is provided with a second pressure transmitter (22), which is electrically connected to the compressor (20); the control module is also configured to adjust the displacement of the compressor (20) according to the detection signal of the second pressure transmitter (22) through a PID algorithm to maintain the output pressure of the buffer tank (21) constant.

6. The on-board liquid hydrogen storage and supply system according to claim 1, characterized in that, The safety venting pipeline includes a safety valve assembly and a manual venting branch connected in parallel. The safety valve group includes a third manual shut-off valve (26), a first safety valve (7), a fourth manual shut-off valve (27), and a second safety valve (8). The third manual shut-off valve (26) and the first safety valve (7) are connected in series to form a first safety branch. The fourth manual shut-off valve (27) and the second safety valve (8) are connected in series to form a second safety branch. The first safety branch and the second safety branch are connected in parallel and communicate with the gas phase area of ​​the vehicle-mounted liquid hydrogen tank (1). The manual venting branch includes a venting valve (10) and a venting check valve (11) connected in sequence. The venting valve (10) is connected to the gas phase region of the vehicle-mounted liquid hydrogen tank (1), and the venting check valve (11) vents gas outward through the venting port.

7. The on-board liquid hydrogen storage and supply system according to claim 6, characterized in that, The opening pressures of the first safety valve (7) and the second safety valve (8) increase sequentially, and both are less than the maximum working pressure of the vehicle-mounted liquid hydrogen tank (1).

8. The on-board liquid hydrogen storage and supply system according to claim 1, characterized in that, The liquid level detection unit is a capacitive liquid level gauge, including a liquid level gauge probe (2) that extends into the vehicle-mounted liquid hydrogen tank (1); the detection component also includes a temperature sensor, which is located in the lower part of the vehicle-mounted liquid hydrogen tank (1).

9. The on-board liquid hydrogen storage and supply system according to claim 8, characterized in that, The control module is configured to: calculate the liquid hydrogen volume based on the signal from the level gauge probe (2), and query a preset liquid hydrogen property table based on the signal from the temperature sensor to obtain the real-time density, thereby calculating the real-time hydrogen capacity.

10. A control method for an on-board liquid hydrogen storage and supply system, used for controlling the on-board liquid hydrogen storage and supply system according to any one of claims 1-9, characterized in that, Includes the following steps: It communicates with the hydrogen refueling machine via CAN bus, receives refueling commands, and feeds back initial status parameters. During the hydrogen supply process, real-time data on tank pressure, buffer tank pressure, liquid level, and temperature are collected. Based on the comparison between the pressure inside the tank and the preset threshold, switch between pressurization mode and economic hydrogen supply mode; Based on the deviation between the buffer tank pressure and the target pressure, the compressor displacement is dynamically adjusted through a PID algorithm to achieve constant pressure hydrogen supply. When overpressure, leakage, or sensor malfunction is detected, the corresponding valve action is performed for emergency handling or downgraded operation.

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