Pressure supplementing method and pressure supplementing system for low-temperature high-pressure hydrogen storage system

Abstract

The invention discloses a pressure supplementing method and system for a low-temperature and high-pressure hydrogen storage system. The pressure supplementing method comprises the steps that when the actual pressure in a hydrogen storage unit in the hydrogen storage system is smaller than the initial judgment pressure, pressure supplementing is started; the real-time temperature in the hydrogen storage unit is collected in the pressure supplementing process, when the real-time temperature is smaller than the hydrogen storage temperature, a main path pressure supplementing mode is started, and otherwise, a bypass pressure supplementing mode is started; in the main path pressure supplementing mode, hydrogen is supplemented into the hydrogen storage unit through a liquid hydrogen pump and a vaporizer on a main path; in the bypass pressure supplementing mode, hydrogen flowing out of the liquid hydrogen pump exchanges heat with stored hydrogen in the hydrogen storage unit and then is supplemented into the hydrogen storage unit; and when the actual pressure in the hydrogen storage unit reaches the ending judgment pressure, hydrogen supplementation is completed, and the hydrogen storage unit with the real-time temperature not reaching the hydrogen storage temperature is heated to the hydrogen storage temperature. A bypass pressure supplementing mode is adopted as a cooling means for the hydrogen storage unit, the bypass pressure supplementing mode and the electric heater in the hydrogen storage unit ensure that the temperature of hydrogen after pressure supplementing reaches a target value, and overcharging or non-supplementing is prevented.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage technology, and in particular to a pressurization method and pressurization system for a cryogenic high-pressure hydrogen storage system. Background Technology

[0002] For applications requiring cryogenic high-pressure hydrogen storage systems, such as novel liquid hydrogen storage and transportation hydrogen refueling stations, these systems release hydrogen. When the hydrogen pressure within the system drops to a certain level, hydrogen needs to be replenished to restore it to a high-pressure state (e.g., 45 MPa, 90 MPa) and ensure a continuous supply of high-pressure hydrogen. Cryogenic high-pressure hydrogen storage systems are characterized by hydrogen storage temperatures below ambient temperature and high storage pressures. During repressurization, it is crucial to simultaneously monitor whether the hydrogen temperature and pressure in each storage unit reach the set values ​​after repressurization. Cryogenic high-pressure hydrogen storage systems exhibit a significant temperature rise during repressurization. Unlike existing ambient-temperature high-pressure hydrogen storage systems, cryogenic high-pressure systems cannot achieve the target hydrogen pressure through natural convection heat transfer with the environment after repressurization, placing higher demands on the repressurization process. Currently, there are no repressurization devices or methods specifically designed for cryogenic high-pressure hydrogen storage systems. In existing liquid hydrogen storage and transportation hydrogen refueling stations, a normal temperature high pressure hydrogen storage system is used. Liquid hydrogen is pressurized and vaporized or vaporized and pressurized to be converted into normal temperature high pressure hydrogen gas and then filled into the hydrogen storage system. This method cannot be directly used for pressurization of low temperature high pressure hydrogen storage systems.

[0003] A Chinese patent document, CN114688445A, published on July 1, 2022, discloses a "Gaseous and Liquid Hydrogen Refueling Station." The station includes a gaseous hydrogen storage tank, a liquid hydrogen storage tank, and at least one refueling unit. The gaseous hydrogen storage tank and the refueling unit are connected via a gaseous hydrogen pipeline, and the liquid hydrogen storage tank and the refueling unit are connected via a liquid hydrogen pipeline. A gaseous hydrogen compressor and a first gas-liquid hydrogen mixer are connected to the gaseous hydrogen pipeline, and a liquid hydrogen pump and a liquid hydrogen distributor are connected to the liquid hydrogen pipeline. The input end of the liquid hydrogen distributor is connected to the liquid hydrogen pump, and the output end of the liquid hydrogen distributor is connected to both the first gas-liquid hydrogen mixer and the refueling unit. The first gas-liquid hydrogen mixer is used for pre-cooling the gaseous and liquid hydrogen mixture. The refueling unit includes a second gas-liquid hydrogen mixer and a hydrogen dispenser. The second gas-liquid hydrogen mixer is used to regulate the hydrogen refueling temperature. This technology pertains to the refueling of hydrogen from a refueling station and is not related to the pressurization of a cryogenic, high-pressure hydrogen storage system. Therefore, existing technologies still suffer from problems such as unclear methods for pressurizing low-temperature high-pressure hydrogen storage systems and difficulty in temperature control during the pressurization process. Summary of the Invention

[0004] The present invention aims to overcome the problem that there is no clear method for pressurizing a low-temperature high-pressure hydrogen storage system in the prior art, and that it is difficult to control the temperature inside the hydrogen storage system during the pressurization process. The invention provides a pressurization method and pressurization system for a low-temperature high-pressure hydrogen storage system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for pressurizing a cryogenic high-pressure hydrogen storage system includes: When the actual pressure inside the hydrogen storage unit in the hydrogen storage system is lower than the initial judgment pressure, pressure replenishment begins. During the pressurization process, the real-time temperature inside the hydrogen storage unit is collected. When the real-time temperature is lower than the hydrogen storage temperature, the main road pressurization mode is entered; otherwise, the bypass pressurization mode is entered. In the main pipeline pressurization mode, hydrogen is replenished into the hydrogen storage unit via the liquid hydrogen pump and vaporizer on the main pipeline; In the bypass pressurization mode, the hydrogen flowing out of the liquid hydrogen pump is replenished into the hydrogen storage unit after exchanging heat with the stored hydrogen in the hydrogen storage unit. When the actual pressure inside the hydrogen storage unit reaches the end judgment pressure, the hydrogen replenishment is completed, and the hydrogen storage unit whose real-time temperature has not reached the hydrogen storage temperature is heated to the hydrogen storage temperature.

[0006] This invention utilizes liquid hydrogen diverted from the outlet of a liquid hydrogen pump to cool the hydrogen gas within the cryogenic high-pressure hydrogen storage unit. This effectively controls the temperature of the unit during the pressurization process, reducing the difficulty of controlling the hydrogen temperature at the vaporizer outlet during pressurization. As a cooling method, it works in conjunction with the electric heater within the unit to ensure the hydrogen temperature reaches the target value after pressurization, preventing overcharging or undercharging. The electric heating device within the unit adjusts the hydrogen temperature to a set value, further reducing the control requirements for hydrogen temperature during pressurization. Furthermore, by appropriately lowering the pressurized hydrogen temperature (i.e., the vaporizer outlet temperature) and reheating the electric heating device, the initial pressurization pressure range of the hydrogen storage system can be expanded, increasing the flexibility of daily pressurization. This solves the problems of unclear pressurization methods and the difficulty of temperature control within the system during pressurization in existing cryogenic high-pressure hydrogen storage systems.

[0007] Preferably, the initial determination pressure and the final determination pressure of the hydrogen storage unit are thresholds based on real-time temperature changes in the hydrogen storage unit. The initial judgment pressure is the pressure value at the real-time temperature corresponding to the initial pressure of the hydrogen storage unit at the hydrogen storage temperature. The termination pressure is the pressure value at the real-time temperature corresponding to the pressure at which the hydrogen storage unit terminates pressure replenishment at the hydrogen storage temperature.

[0008] As a preferred embodiment, in the main road pressurization mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure. When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the actual pressure has not reached the final judgment pressure but the real-time temperature exceeds the hydrogen storage temperature, the bypass pressure replenishment mode is switched to.

[0009] Preferably, in the bypass pressure replenishment mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure. When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the real-time temperature is less than or equal to the minimum allowable temperature of the hydrogen storage unit, the system switches to main pipeline pressurization mode.

[0010] Preferably, the hydrogen storage system includes several hydrogen storage units. When a main pressurization line containing a liquid hydrogen pump and a vaporizer connects to several hydrogen storage units, the hydrogen storage units that need pressurization are pressurized in sequence according to the hydrogen storage temperature from low to high. When each hydrogen storage unit has a corresponding main pressurization line, independent pressurization operations are carried out simultaneously for hydrogen storage units that require pressurization.

[0011] A pressurization system for a cryogenic high-pressure hydrogen storage system includes: a hydrogen storage system comprising a plurality of hydrogen storage units; The liquid hydrogen pump pressurizes the liquid hydrogen output from the liquid hydrogen storage tank and outputs it to the vaporizer; The vaporizer vaporizes the liquid hydrogen output from the liquid hydrogen pump into hydrogen gas and adjusts it to the set temperature before replenishing it into the hydrogen storage unit. The pressure-replenishing bypass pipeline starts at the outlet of the liquid hydrogen pump, the middle section is a heat exchange pipeline installed in the hydrogen storage unit, and the end section merges into the outlet of the vaporizer. The pressure replenishment controller controls the pressure replenishment of the hydrogen storage unit and switches between different pressure replenishment modes.

[0012] Preferably, when a main pressurization line including a liquid hydrogen pump and a vaporizer is connected to several hydrogen storage units in the hydrogen storage system, several pressurization bypass lines are connected from the outlet of the liquid hydrogen pump at the same time, and the number of pressurization bypass lines is the same as the storage capacity of the hydrogen storage unit. The pressurization controller is configured to pressurize the hydrogen storage units that need pressurization in sequence from low to high hydrogen storage temperature.

[0013] As a preferred option, when each hydrogen storage unit has a corresponding main pressurization path, each main pressurization path is configured with a corresponding main pressurization path; The pressure replenishment controller is configured to simultaneously perform independent pressure replenishment operations on the hydrogen storage units that require pressure replenishment.

[0014] Preferably, a pump solenoid valve is provided before the inlet of each liquid hydrogen pump, a pressure replenishing solenoid valve is provided before the inlet of each hydrogen storage unit, and a bypass solenoid valve is provided near the liquid hydrogen pump for each pressure replenishing bypass. The pressure replenishment controller controls the pressure replenishment of the hydrogen storage unit and switches the pressure replenishment mode by controlling the opening and closing of each solenoid valve.

[0015] Preferably, the heat exchange pipeline in the middle section of the pressure replenishment bypass is a heat exchange coil; the heat exchange coil is installed inside the insulating shell of the hydrogen storage unit and wrapped around the outside of the hydrogen storage container, and the hydrogen in the heat exchange coil exchanges heat with the hydrogen in the hydrogen storage container. The hydrogen storage container is equipped with a pressure detection unit, a temperature detection unit, and an electric heating device connected to a pressure replenishment controller.

[0016] The present invention has the following beneficial effects: Using liquid hydrogen diverted from the outlet of the liquid hydrogen pump to cool the hydrogen in the low-temperature, high-pressure hydrogen storage unit effectively achieves temperature control during the pressurization process, reducing the difficulty of controlling the hydrogen temperature at the vaporizer outlet during pressurization. As a cooling method, it works together with the electric heater in the low-temperature, high-pressure hydrogen storage unit to ensure that the hydrogen temperature inside the storage unit reaches the target value after pressurization, preventing overcharging or undercharging. Through the electric heating device in the storage unit, the hydrogen temperature can be adjusted to the set value, thereby reducing the control requirements for the hydrogen temperature during pressurization. Furthermore, by appropriately lowering the pressurized hydrogen temperature (i.e., the vaporizer outlet temperature) and reheating the electric heating device, the range of the initial pressurization pressure limit of the hydrogen storage system can be expanded, improving the flexibility of daily pressurization processes. Attached Figure Description

[0017] Figure 1 This is a flowchart of the pressurization method for the low-temperature high-pressure hydrogen storage system in this invention.

[0018] Figure 2 This is a schematic diagram of the pressurization system of the low-temperature high-pressure hydrogen storage system in this invention.

[0019] Figure 3 This is another schematic diagram of the pressurization system of the low-temperature high-pressure hydrogen storage system in this invention.

[0020] In the diagram: 1. Liquid hydrogen storage tank; 2. Liquid hydrogen pump; 21. First liquid hydrogen pump; 22. Second liquid hydrogen pump; 3. Check valve; 31. First check valve; 32. Second check valve; 4. Vaporizer; 41. First vaporizer; 42. Second vaporizer; 51. First hydrogen storage unit; 52. Second hydrogen storage unit; 61. First heat exchange coil; 62. Second heat exchange coil; 7. Pressure replenishment controller; 81. First pump solenoid valve; 82. Second pump solenoid valve; 83. First pressure replenishment solenoid valve; 84. Second pressure replenishment solenoid valve; 85. Third pump solenoid valve; 86. Third pressure replenishment solenoid valve; 87. Fourth pressure replenishment solenoid valve; 91. First bypass solenoid valve; 92. Second bypass solenoid valve; 93. Third bypass solenoid valve; 94. Fourth bypass solenoid valve. Detailed Implementation

[0021] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, a method for pressurizing a cryogenic high-pressure hydrogen storage system includes: When the actual pressure inside the hydrogen storage unit in the hydrogen storage system is lower than the initial judgment pressure, pressure replenishment begins. During the pressurization process, the real-time temperature inside the hydrogen storage unit is collected. When the real-time temperature is lower than the hydrogen storage temperature, the main road pressurization mode is entered; otherwise, the bypass pressurization mode is entered. In the main pipeline pressurization mode, hydrogen is replenished into the hydrogen storage unit via the liquid hydrogen pump and vaporizer on the main pipeline; In the bypass pressurization mode, the hydrogen flowing out of the liquid hydrogen pump is replenished into the hydrogen storage unit after exchanging heat with the stored hydrogen in the hydrogen storage unit. When the actual pressure inside the hydrogen storage unit reaches the end judgment pressure, the hydrogen replenishment is completed, and the hydrogen storage unit whose real-time temperature has not reached the hydrogen storage temperature is heated to the hydrogen storage temperature.

[0023] This invention utilizes liquid hydrogen diverted from the outlet of a liquid hydrogen pump to cool the hydrogen gas within the cryogenic high-pressure hydrogen storage unit. This effectively controls the temperature of the unit during the pressurization process, reducing the difficulty of controlling the hydrogen temperature at the vaporizer outlet during pressurization. As a cooling method, it works in conjunction with the electric heater within the unit to ensure the hydrogen temperature reaches the target value after pressurization, preventing overcharging or undercharging. The electric heating device within the unit adjusts the hydrogen temperature to a set value, further reducing the control requirements for hydrogen temperature during pressurization. Furthermore, by appropriately lowering the pressurized hydrogen temperature (i.e., the vaporizer outlet temperature) and reheating the electric heating device, the initial pressurization pressure range of the hydrogen storage system can be expanded, increasing the flexibility of daily pressurization. This solves the problems of unclear pressurization methods and the difficulty of temperature control within the system during pressurization in existing cryogenic high-pressure hydrogen storage systems.

[0024] Each hydrogen storage unit has its own storage temperature and pressure. Different hydrogen storage units can be set with different storage temperatures and pressures as needed. During the pressurization process of any hydrogen storage unit, it is necessary to collect the real-time temperature and actual pressure of the hydrogen stored inside in real time, and switch between different pressurization modes based on the collected data.

[0025] Specifically, the main pipeline pressurization mode is a mode in which hydrogen is replenished to the hydrogen storage unit through the main pressurization pipeline. The liquid hydrogen flowing out of the liquid hydrogen storage tank is transformed into suitable low-temperature and high-pressure hydrogen after passing through the liquid hydrogen pump and vaporizer and stored in the corresponding hydrogen storage unit. The main pipeline is equipped with corresponding solenoid valves to realize the start and end of hydrogen replenishment, and is also equipped with corresponding check valves and other components to ensure the effective operation of the pipeline.

[0026] The bypass pressurization mode involves replenishing hydrogen to the hydrogen storage unit via a pressurization bypass connected in parallel with the main pressurization line. This mode offers two options: one is to replenish the hydrogen storage unit solely through the pressurization bypass, while the other is to split the liquid hydrogen at the pump outlet, with some replenishing the main pressurization line and the rest through the bypass. Both methods utilize the liquid hydrogen in the bypass to cool the higher-temperature hydrogen in the storage unit, effectively using the cooling capacity of the liquid hydrogen to control the temperature within the storage unit.

[0027] In cryogenic high-pressure hydrogen storage systems, the hydrogen storage unit has an outer insulating shell that prevents heat exchange between the internal hydrogen and the external environment. Therefore, besides the heat generated during pressurization, there is no natural convection heat transfer after pressurization, posing a significant temperature control challenge. This invention addresses this by incorporating two temperature control measures: a pressurization bypass and heating of the hydrogen storage unit, in addition to the existing main pressurization circuit for normal pressurization. Normal pressurization via the main circuit causes the temperature inside the hydrogen storage unit to rise continuously. To prevent the temperature from exceeding the required storage temperature, a pressurization bypass is added, utilizing the cooling capacity of liquid hydrogen to cool the hydrogen inside the storage unit, thereby lowering the temperature. Furthermore, there are situations where the temperature of the hydrogen storage unit does not reach the required storage temperature after replenishment. In this case, heating can be applied using an internal heating device to raise the temperature. In short, precise temperature control within the hydrogen storage unit is achieved through the cooling of the bypass pressurization mode and the heating of the heating device.

[0028] Furthermore, the initial and final determination pressures of the hydrogen storage unit are based on thresholds for real-time temperature changes within the hydrogen storage unit. The initial judgment pressure is the pressure value at the real-time temperature corresponding to the initial pressure of the hydrogen storage unit at the hydrogen storage temperature. The termination pressure is the pressure value at the real-time temperature corresponding to the pressure at which the hydrogen storage unit terminates pressure replenishment at the hydrogen storage temperature.

[0029] In this invention, the pressurization method for a low-temperature, high-pressure hydrogen storage system will simultaneously set a corresponding temperature-pressure correlation algorithm. Based on the characteristics of the hydrogen storage system, the correlation between the real-time temperature and the actual pressure in the hydrogen storage unit will be obtained (which can be calculated based on the ideal gas law and the actual physical properties of hydrogen). The initial pressurization pressure at the hydrogen storage temperature will be converted into the initial judgment pressure at the real-time temperature according to the change in real-time temperature, and the final pressurization pressure at the hydrogen storage temperature will be converted into the final judgment pressure at the real-time temperature according to the change in real-time temperature.

[0030] This dynamic method of calculating the initial and final judgment pressures improves the actual pressure replenishment accuracy by dynamically optimizing parameters, and can avoid the problem of overcharging or undercharging of the hydrogen storage unit due to temperature changes.

[0031] As a specific implementation, in the main pipeline pressurization mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure; When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the actual pressure has not reached the final judgment pressure but the real-time temperature exceeds the hydrogen storage temperature, the bypass pressure replenishment mode is switched to.

[0032] In the main pipeline pressurization mode, it is necessary to continuously monitor the temperature and pressure changes within the hydrogen storage unit and update the termination judgment pressure in real time. When an abnormal situation (such as excessively high temperature) is detected, the pressurization mode switching is automatically triggered. The method of this invention provides real-time safety monitoring to prevent system overheating, and ensures that the pressurization process is always carried out under optimal conditions through intelligent switching, reducing the risk of human error.

[0033] Specifically, in the main pipeline pressurization mode, the main pipeline connected to the hydrogen storage unit operates. The liquid hydrogen storage tank delivers liquid hydrogen to the liquid hydrogen pump, which pressurizes the liquid hydrogen and outputs it to the vaporizer. The vaporizer vaporizes the liquid hydrogen into low-temperature, high-pressure hydrogen gas, adjusts it to the set temperature, and then delivers it to the hydrogen storage unit for pressurization. During the main pipeline pressurization mode, the real-time temperature and actual pressure within the hydrogen storage unit are collected.

[0034] If the actual pressure reaches the end judgment pressure at the real-time temperature and the real-time temperature does not exceed the hydrogen storage temperature, it means that the hydrogen replenishment has been completed but the temperature has not yet reached the requirement. Therefore, the pressurization operation will no longer be carried out, and the subsequent heating process will begin. The electric heating device in the hydrogen storage unit will heat the hydrogen until the real-time temperature reaches the hydrogen storage temperature, thus completing the pressurization of the hydrogen storage unit.

[0035] If the actual pressure does not reach the final pressure at the real-time temperature, but the real-time temperature has already exceeded the hydrogen storage temperature, continuing to use the main pressure replenishment mode will cause the temperature to continue to rise, which does not meet the requirements of the hydrogen storage temperature. Therefore, it is necessary to switch to the bypass pressure replenishment mode, using liquid hydrogen in the bypass to cool the hydrogen storage unit while replenishing hydrogen pressure.

[0036] In bypass pressurization mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure; When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the real-time temperature is less than or equal to the minimum allowable temperature of the hydrogen storage unit, the system switches to main pipeline pressurization mode.

[0037] In bypass pressurization mode, the cooling capacity of liquid hydrogen in the bypass pressurization channel is used to cool the hydrogen storage unit. When the temperature drops to less than or equal to the minimum allowable temperature, the system automatically switches back to main pressurization mode to prevent over-cooling. This invention effectively utilizes the cooling capacity of liquid hydrogen, improves energy efficiency, avoids damage to the system caused by over-cooling, and achieves precise control of the cooling process.

[0038] Specifically, in bypass pressurization mode, the pressurization bypass connected to the hydrogen storage unit operates. The liquid hydrogen storage tank delivers liquid hydrogen to the liquid hydrogen pump, which pressurizes the liquid hydrogen and outputs it from the pump outlet. The liquid hydrogen then enters the pressurization bypass at the pump outlet and is delivered to the hydrogen storage unit. There, it exchanges heat with the stored hydrogen through heat exchange pipes before being delivered to the vaporizer outlet and finally replenishing the hydrogen storage unit. Optionally, the liquid hydrogen is split at the pump outlet; one portion continues to pressurize the hydrogen storage unit via the main pressurization path, while the other portion pressurizes the unit via the pressurization bypass path.

[0039] If the actual pressure reaches the end judgment pressure at the real-time temperature and the real-time temperature does not exceed the hydrogen storage temperature, it means that the hydrogen replenishment has been completed but the temperature has not yet reached the requirement. Therefore, the pressurization operation will no longer be carried out, and the subsequent heating process will begin. The electric heating device in the hydrogen storage unit will heat the hydrogen until the real-time temperature reaches the hydrogen storage temperature, thus completing the pressurization of the hydrogen storage unit.

[0040] If the actual pressure fails to reach the termination pressure at the real-time temperature, but the real-time temperature is less than or equal to the preset minimum allowable temperature, continuing to pressurize in the bypass pressurization mode will further reduce the temperature and damage the system. Therefore, it is necessary to switch to the main pressurization mode to raise the temperature in the hydrogen storage unit again. In this case, a higher-pressure liquid hydrogen pump and vaporizer can also be used to pressurize the hydrogen storage unit, making the temperature rise effect within the unit more significant and quickly restoring the hydrogen temperature.

[0041] As an optional embodiment, the hydrogen storage system includes several hydrogen storage units. When a main pressurization line containing a liquid hydrogen pump and a vaporizer connects to several hydrogen storage units, the hydrogen storage units that need pressurization are pressurized in sequence according to the hydrogen storage temperature from low to high. When each hydrogen storage unit has a corresponding main pressurization line, independent pressurization operations are carried out simultaneously for hydrogen storage units that require pressurization.

[0042] For multi-stage hydrogen storage systems, two different strategies can be adopted: when multiple hydrogen storage units share the same main pressurization path, they are pressurized sequentially in order of increasing hydrogen storage temperature; when each hydrogen storage unit uses an independent main pressurization path, multiple hydrogen storage units can be pressurized simultaneously. The method of this invention provides a flexible system structure and pressurization method configuration scheme, optimizes the timing of the pressurization process, improves pressurization efficiency, and can adapt to hydrogen storage systems of different scales and requirements.

[0043] In addition to a pressurization method for a cryogenic high-pressure hydrogen storage system, the present invention also provides a pressurization system for a cryogenic high-pressure hydrogen storage system, comprising: a hydrogen storage system including a plurality of hydrogen storage units; The liquid hydrogen pump pressurizes the liquid hydrogen output from the liquid hydrogen storage tank and outputs it to the vaporizer; The vaporizer vaporizes the liquid hydrogen output from the liquid hydrogen pump into hydrogen gas and adjusts it to the set temperature before replenishing it into the hydrogen storage unit. The pressure-replenishing bypass pipeline starts at the outlet of the liquid hydrogen pump, the middle section is a heat exchange pipeline installed in the hydrogen storage unit, and the end section merges into the outlet of the vaporizer. The pressure replenishment controller controls the pressure replenishment of the hydrogen storage unit and switches between different pressure replenishment modes.

[0044] The heat exchange pipeline in the middle section of the pressure replenishment bypass is a heat exchange coil; the heat exchange coil is set inside the insulating shell of the hydrogen storage unit and wrapped around the outside of the hydrogen storage container, and the hydrogen in the heat exchange coil exchanges heat with the hydrogen in the hydrogen storage container; the structure of the hydrogen storage unit from the outside to the inside consists of an insulating shell, a heat exchange coil and a hydrogen storage container; the hydrogen storage container is equipped with a pressure detection unit, a temperature detection unit and an electric heating device connected to the pressure replenishment controller.

[0045] The system of this invention includes a complete pressurization pipeline network. The main pressurization line connects the liquid hydrogen pump, vaporizer, and hydrogen storage unit, while the bypass forms a cooling circuit. All pipelines utilize existing materials to ensure safety under cryogenic and high-pressure conditions. The system incorporates solenoid valve assemblies at key nodes in the pipelines, including pump solenoid valves, pressurization solenoid valves, and bypass solenoid valves. The pressurization controller controls the opening and closing combinations of these valves to achieve different pressurization modes and strategies. The system of this invention provides precise fluid control capabilities; the solenoid valves offer fast response times and high control accuracy, enabling complex control logic to be implemented through valve assembly combinations.

[0046] Specifically, the pressurization system of the cryogenic high-pressure hydrogen storage system of the present invention includes a liquid hydrogen storage tank, a liquid hydrogen pump and a vaporizer connected in sequence, which are used to replenish cryogenic high-pressure hydrogen to the cryogenic high-pressure hydrogen storage system. The hydrogen storage system can be divided into n different hydrogen storage units according to the highest hydrogen storage pressure (here, the highest hydrogen storage pressure can be equivalent to the pressurization termination pressure of the hydrogen storage unit at the hydrogen storage temperature), where n≥1. The vaporizer is connected to the hydrogen storage system through a pipeline, and the pressurization controller is connected to the solenoid valve in the overall pipeline network.

[0047] The liquid hydrogen pump is used to pressurize the cryogenic low-pressure liquid hydrogen in the liquid hydrogen storage tank into cryogenic high-pressure liquid hydrogen or cryogenic high-pressure supercritical hydrogen. The vaporizer is used to adjust the temperature of the cryogenic high-pressure liquid hydrogen or cryogenic high-pressure supercritical hydrogen output by the liquid hydrogen pump to a set value and store it in the hydrogen storage unit of the hydrogen storage system.

[0048] The hydrogen storage temperature of each hydrogen storage unit in a hydrogen storage system may differ. To facilitate the implementation of the pressure replenishment control logic, each hydrogen storage unit can be numbered sequentially. For example, when n=2, T1≤T2, P1≤P2, meaning the hydrogen storage temperature of hydrogen storage unit 1 is less than or equal to the hydrogen storage temperature of hydrogen storage unit 2, and the maximum hydrogen storage pressure of hydrogen storage unit 1 is less than or equal to the maximum hydrogen storage pressure of hydrogen storage unit 2. When n≥3, T1≤……≤T(n-1)≤Tn, P1≤……≤P(n-1)≤Pn, meaning the smaller the serial number of the hydrogen storage unit, the lower its hydrogen storage temperature and maximum hydrogen storage pressure. The initial pressure of repressurization for each hydrogen storage unit in the hydrogen storage system may also be different. When n=2, Ps1≤Ps2, that is, the initial pressure of repressurization for the first hydrogen storage unit is less than or equal to the initial pressure of repressurization for the second hydrogen storage unit; when n≥3, Ps1≤……≤Ps(n-1)≤Psn; that is, the smaller the number of the hydrogen storage unit, the smaller its initial pressure of repressurization.

[0049] The maximum output pressure of the liquid hydrogen pump is more than 5 MPa higher than the maximum pressure of all hydrogen storage units in the hydrogen storage system. A flow control valve can be installed between the vaporizer and the hydrogen storage system for flow control. Temperature and pressure sensors and an electric heating device are installed in the hydrogen storage unit. The electric heating device is used to heat the low-temperature, high-pressure hydrogen in the hydrogen storage unit after pressurization.

[0050] Example 1, such as Figure 2 The diagram shows a pressure replenishment system according to the present invention. When each hydrogen storage unit corresponds to a main pressure replenishment path, each main pressure replenishment path is configured with a corresponding pressure replenishment bypass. A pump solenoid valve is installed before the inlet of each liquid hydrogen pump, a pressure replenishment solenoid valve is installed before the inlet of each hydrogen storage unit, and a bypass solenoid valve is installed near the liquid hydrogen pump on each pressure replenishment bypass. The pressure replenishment controller is configured to simultaneously perform independent pressure replenishment operations on the hydrogen storage units that require pressure replenishment, and to control the pressure replenishment of the hydrogen storage units and switch the pressure replenishment mode by controlling the opening and closing of each solenoid valve.

[0051] Specifically, the liquid hydrogen flowing out of liquid hydrogen storage tank 1 flows into the first liquid hydrogen pump 21 through the first pump solenoid valve 81 for pressurization before flowing out again. Then, it flows into the first vaporizer 41 through the first check valve 31. The hydrogen gas vaporized in the first vaporizer 41 is then transported to the first hydrogen storage unit 51 for pressurization and storage via the first pressure replenishment solenoid valve 83. The purpose of setting the check valve is to prevent hydrogen backflow at the vaporizer, which is an optimization to improve the pressure replenishment operation. Alternatively, the check valve can be omitted, and in this case, the inlet of the pressure replenishment bypass is connected to the outlet of the liquid hydrogen pump.

[0052] Liquid hydrogen flowing out of the outlet of the first liquid hydrogen pump 21 can also flow into the first heat exchange coil 61 through the first bypass solenoid valve 91. After exchanging heat with the hydrogen stored in the first hydrogen storage unit through the first heat exchange coil 61, it is transported back to the outlet of the first vaporizer 41 and then transported to the first hydrogen storage unit 51 for pressurization storage via the first pressure replenishment solenoid valve 83.

[0053] The liquid hydrogen flowing through the pressure bypass passes through the coil structure in the low-temperature high-pressure hydrogen storage unit, which cools the hydrogen gas in the storage unit, allowing the hydrogen gas temperature in the storage unit to reach the target value. After heat exchange, the liquid hydrogen is converted into low-temperature high-pressure hydrogen gas, which flows into the outlet pipeline after the vaporizer and is then charged into the low-temperature high-pressure hydrogen storage unit, thus eliminating the waste of liquid hydrogen.

[0054] Liquid hydrogen flowing out of liquid hydrogen storage tank 1 flows into the second liquid hydrogen pump 22 through the second pump solenoid valve 82 for pressurization and then flows out. It then flows into the second vaporizer 42 through the second check valve 32. The hydrogen gas vaporized in the second vaporizer 42 is then transported to the second hydrogen storage unit 52 for pressurization and storage through the second pressure replenishment solenoid valve 84.

[0055] Liquid hydrogen flowing out of the outlet of the second liquid hydrogen pump 22 can also flow into the second heat exchange coil 62 through the second bypass solenoid valve 92. After exchanging heat with the hydrogen stored in the second hydrogen storage unit through the second heat exchange coil 62, it is transported back to the outlet of the second vaporizer 42 and then transported to the second hydrogen storage unit 52 for pressurization storage via the second pressure replenishing solenoid valve 84.

[0056] In this embodiment, each set of liquid hydrogen pumps and vaporizers is connected to a single hydrogen storage unit. For example, the first liquid hydrogen pump 21 and the first vaporizer 41 are connected to the first hydrogen storage unit 51. According to the system configuration, the hydrogen storage temperature of the first hydrogen storage unit 51 is -60°C (i.e., 213K), its pressure replenishment start pressure and pressure replenishment termination pressure are 25MPa and 45MPa respectively, and its minimum allowable temperature is -90°C (i.e., 183K); the hydrogen storage temperature of the second hydrogen storage unit 52 is -45°C (i.e., 228K), its pressure replenishment start pressure and pressure replenishment termination pressure are 40MPa and 45MPa respectively, and its minimum allowable temperature is -90°C (i.e., 183K).

[0057] When the actual pressure of hydrogen in the hydrogen storage unit is lower than the initial judgment pressure, such as when the actual pressure of the first hydrogen storage unit 51 is lower than 25 MPa (25 MPa is the pressure at the hydrogen storage temperature; if the real-time temperature is not the hydrogen storage temperature, a corresponding conversion is required), the pressure replenishment controller 7 controls the start of pressure replenishment for the first hydrogen storage unit 51. This judgment process requires real-time acquisition of the real-time temperature and actual pressure within the hydrogen storage unit, comparing the actual pressure with the initial judgment pressure converted from the real-time temperature to determine whether to initiate pressure replenishment.

[0058] When pressurization begins, the pressurization controller 7 starts the first liquid hydrogen pump 21, and the first pump solenoid valve 81 and the first pressurization solenoid valve 83 open. The first liquid hydrogen pump 21 pressurizes the low-pressure liquid hydrogen from the liquid hydrogen storage tank 1 and sends it to the first vaporizer 41. The first vaporizer 41 raises the temperature of the low-temperature, high-pressure supercritical hydrogen to a preset value and then fills the first hydrogen storage unit 51. The pressurization controller 7 updates the end-of-pressurization judgment pressure based on the real-time temperature feedback from the hydrogen temperature sensor in the hydrogen storage unit 51. For example, if the actual hydrogen temperature at the end of pressurization in the first hydrogen storage unit 51 is -70°C, the corresponding end-of-pressurization judgment pressure should be 42.9 MPa (i.e., the 45 MPa pressurization end-of-pressurization pressure is converted based on the comparison between the real-time temperature and the hydrogen storage temperature). After pressurization, the electric heating device in the first hydrogen storage unit 51 starts to heat the hydrogen until its temperature reaches -60°C. The pressurization control logic for other hydrogen storage units is also as described above, and the pressurization process for each hydrogen storage unit can be performed independently.

[0059] During the pressurization process, if the actual pressure does not reach the final judgment pressure, but the real-time temperature exceeds -60℃ and reaches -55℃, continuing pressurization through the main pressurization circuit would cause the temperature to rise further, failing to meet the final real-time temperature requirement. Therefore, the pressurization controller 7 controls the first bypass solenoid valve 91 to open. Liquid hydrogen flowing from the first liquid hydrogen pump flows into the first heat exchange coil 61 through the first bypass solenoid valve 91, cooling the hydrogen in the first hydrogen storage unit 51. Meanwhile, the liquid hydrogen in the bypass absorbs heat and vaporizes into low-temperature, high-pressure hydrogen, which flows into the outlet of the first vaporizer 41 and is input into the first hydrogen storage unit 51 via the first pressurization solenoid valve 83. Through the cooling effect of the liquid hydrogen in the bypass pressurization mode, the temperature in the hydrogen storage unit is continuously reduced to below -60℃ while continuing to pressurize the hydrogen storage unit until the actual pressure in the first hydrogen storage unit 51 reaches the final judgment pressure. The subsequent heating operation process remains unchanged and will not be described in detail.

[0060] During the pressure replenishment process via the bypass mode, a situation arises where the actual pressure has not reached the termination pressure, but the real-time temperature within the first hydrogen storage unit 51 is at or below the minimum allowable temperature of -90°C. Continuing to replenish pressure via the bypass in this case would further lower the temperature, potentially damaging the hydrogen storage unit or causing a hazard. Therefore, the pressure replenishment controller 7 needs to close the first bypass solenoid valve 91, ending the bypass pressure replenishment mode and switching to the main pressure replenishment mode. This mode simultaneously replenishes the pressure in the first hydrogen storage unit 51 and raises its real-time temperature until the actual pressure within the first hydrogen storage unit 51 reaches the termination pressure.

[0061] The pressurization method in this embodiment is highly targeted and can meet the precise parameter requirements of specific hydrogen storage units; the control system is simple, reliable, and has a fast response speed; the pressurization processes of each hydrogen storage unit do not interfere with each other, resulting in high system stability; and the equipment configuration is flexible and can be expanded according to actual needs.

[0062] Example 2, as follows Figure 3 The diagram shows another pressurization system of the present invention. When a main pressurization line including a liquid hydrogen pump and a vaporizer is connected to several hydrogen storage units in a hydrogen storage system, several pressurization bypass lines are simultaneously connected from the outlet of the liquid hydrogen pump. The number of pressurization bypass lines is the same as the storage capacity of the hydrogen storage units. A pump solenoid valve is provided before the inlet of each liquid hydrogen pump, a pressurization solenoid valve is provided before the inlet of each hydrogen storage unit, and a bypass solenoid valve is provided near the liquid hydrogen pump for each pressurization bypass line. The pressure replenishment controller is configured to replenish the hydrogen storage units that need to be replenished in sequence according to the hydrogen storage temperature from low to high. The pressure replenishment control of the hydrogen storage units and the switching of the pressure replenishment mode are controlled by controlling the opening and closing of each solenoid valve.

[0063] When a set of liquid hydrogen pumps and vaporizers are connected to multiple hydrogen storage units with different hydrogen storage temperatures, the vaporizer is equipped with multiple outlets. The hydrogen temperature at each outlet is determined according to the hydrogen storage temperature requirements of each corresponding hydrogen storage unit. When the number of outlets n≥2, To1≤……≤To(n-1)≤Ton.

[0064] Specifically, for a multi-outlet configuration of a vaporizer, with n outlets corresponding to n hydrogen storage units, n-1 two-position three-way valves are required. The first outlet of the vaporizer is connected to the first and second pipelines via the first two-position three-way valve. The first pipeline is connected to the first hydrogen storage unit. The second pipeline is connected to the third and fourth pipelines via the second two-position three-way valve. The third pipeline is connected to the second hydrogen storage unit. The fourth pipeline is connected to the fifth and sixth pipelines via the third two-position three-way valve. The fifth pipeline is connected to the third hydrogen storage unit, and so on, until the last two-position three-way valve connects to two pipelines that are connected to the last two hydrogen storage units.

[0065] Liquid hydrogen flowing from liquid hydrogen storage tank 1 flows into liquid hydrogen pump 2 via the third pump solenoid valve 85 for pressurization before flowing out again. It then flows into vaporizer 4 via check valve 3. The vaporized hydrogen in vaporizer 4 is divided into two streams. The first stream is delivered to the first hydrogen storage unit 51 for pressurization and storage via the third pressure-replenishing solenoid valve 86. The second stream is delivered to the second hydrogen storage unit 52 for pressurization and storage via the fourth pressure-replenishing solenoid valve 87.

[0066] Liquid hydrogen flowing out of the outlet of liquid hydrogen pump 2 can also flow into the first heat exchange coil 61 through the third bypass solenoid valve 93. After exchanging heat with the hydrogen stored in the first hydrogen storage unit through the first heat exchange coil 61, it is transported back to the outlet of vaporizer 4 and then transported to the first hydrogen storage unit 51 for pressurization storage through the third pressure replenishment solenoid valve 86.

[0067] Liquid hydrogen flowing out of the outlet of liquid hydrogen pump 2 can also flow into the second heat exchange coil 62 through the fourth bypass solenoid valve 94. After exchanging heat with the hydrogen stored in the second hydrogen storage unit through the second heat exchange coil 62, it is transported back to the outlet of vaporizer 4 and then transported to the second hydrogen storage unit 52 for pressurization storage through the fourth pressure replenishment solenoid valve 87.

[0068] In this embodiment, a set of liquid hydrogen pumps and vaporizers are simultaneously connected to all hydrogen storage units. For example, liquid hydrogen pump 2 and vaporizer 4 are simultaneously connected to the first hydrogen storage unit 51 and the second hydrogen storage unit 52. According to the system configuration, the hydrogen storage temperature of the first hydrogen storage unit 51 is -60℃ (i.e., 213K), its pressure replenishment start pressure and pressure replenishment termination pressure are 25MPa and 45MPa respectively, and its minimum allowable temperature is -90℃ (i.e., 183K); the hydrogen storage temperature of the second hydrogen storage unit 52 is -45℃ (i.e., 228K), its pressure replenishment start pressure and pressure replenishment termination pressure are 40MPa and 45MPa respectively, and its minimum allowable temperature is -90℃ (i.e., 183K).

[0069] For scenarios where only one hydrogen storage unit requires pressurization, the pressurization process can be performed as described in Example 1. When multiple hydrogen storage units require pressurization, such as when the actual pressures of the first hydrogen storage unit 51 and the second hydrogen storage unit 52 are both less than or equal to their corresponding initial judgment pressures, hydrogen replenishment should be carried out sequentially in order of increasing hydrogen storage temperature. The hydrogen storage temperature of the first hydrogen storage unit 51 is -60°C, and the hydrogen storage temperature of the second hydrogen storage unit 52 is -45°C. Since the hydrogen storage temperature of the first hydrogen storage unit is lower than that of the second hydrogen storage unit, the liquid hydrogen pump 2 and the vaporizer 4 prioritize pressurizing the first hydrogen storage unit 51, and the pressurization process is as described in Example 1. After the first hydrogen storage unit 51 has completed pressurization, the vaporizer 4 switches to connect with the second hydrogen storage unit 52 and continues to pressurize the second hydrogen storage unit 52 until all hydrogen storage units requiring pressurization have been pressurized.

[0070] The above embodiments are further elaborations and descriptions of the present invention to facilitate understanding, and are not intended to limit the present invention in any way. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for pressurizing a cryogenic high-pressure hydrogen storage system, characterized in that, include: When the actual pressure inside the hydrogen storage unit in the hydrogen storage system is lower than the initial judgment pressure, pressure replenishment begins. During the pressurization process, the real-time temperature inside the hydrogen storage unit is collected. When the real-time temperature is lower than the hydrogen storage temperature, the main road pressurization mode is entered; otherwise, the bypass pressurization mode is entered. In the main pipeline pressurization mode, hydrogen is replenished into the hydrogen storage unit via the liquid hydrogen pump and vaporizer on the main pipeline; In the bypass pressurization mode, the hydrogen flowing out of the liquid hydrogen pump is replenished into the hydrogen storage unit after exchanging heat with the stored hydrogen in the hydrogen storage unit. When the actual pressure inside the hydrogen storage unit reaches the end judgment pressure, the hydrogen replenishment is completed, and the hydrogen storage unit whose real-time temperature has not reached the hydrogen storage temperature is heated to the hydrogen storage temperature.

2. The pressurization method for a cryogenic high-pressure hydrogen storage system according to claim 1, characterized in that, The initial determination pressure and the final determination pressure of the hydrogen storage unit are thresholds based on real-time temperature changes within the hydrogen storage unit. The initial judgment pressure is the pressure value at the real-time temperature corresponding to the initial pressure of the hydrogen storage unit at the hydrogen storage temperature. The termination pressure is the pressure value at the real-time temperature corresponding to the pressure at which the hydrogen storage unit terminates pressure replenishment at the hydrogen storage temperature.

3. A method for pressurizing a cryogenic high-pressure hydrogen storage system according to claim 1 or 2, characterized in that, In the main road pressurization mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure; When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the actual pressure has not reached the final judgment pressure but the real-time temperature exceeds the hydrogen storage temperature, the bypass pressure replenishment mode is switched to.

4. A method for pressurizing a cryogenic high-pressure hydrogen storage system according to claim 1 or 2, characterized in that, In the bypass pressure replenishment mode, the real-time temperature inside the hydrogen storage unit is collected to update the end judgment pressure; When the actual pressure reaches the termination judgment pressure and the real-time temperature does not exceed the hydrogen storage temperature, the subsequent heating process begins. When the real-time temperature is less than or equal to the minimum allowable temperature of the hydrogen storage unit, the system switches to main pipeline pressurization mode.

5. A method for pressurizing a cryogenic high-pressure hydrogen storage system according to claim 1 or 2, characterized in that, The hydrogen storage system includes several hydrogen storage units. When a main pressurization line containing a liquid hydrogen pump and a vaporizer connects to several hydrogen storage units, the hydrogen storage units that need pressurization are pressurized in sequence according to the hydrogen storage temperature from low to high. When each hydrogen storage unit has a corresponding main pressurization line, independent pressurization operations are carried out simultaneously for hydrogen storage units that require pressurization.

6. A pressurization system for a cryogenic high-pressure hydrogen storage system, applicable to the pressurization method for the cryogenic high-pressure hydrogen storage system as described in any one of claims 1-5, characterized in that, include: A hydrogen storage system, comprising several hydrogen storage units; The liquid hydrogen pump pressurizes the liquid hydrogen output from the liquid hydrogen storage tank and outputs it to the vaporizer; The vaporizer vaporizes the liquid hydrogen output from the liquid hydrogen pump into hydrogen gas and adjusts it to the set temperature before replenishing it into the hydrogen storage unit. The pressure-replenishing bypass pipeline starts at the outlet of the liquid hydrogen pump, the middle section is a heat exchange pipeline installed in the hydrogen storage unit, and the end section merges into the outlet of the vaporizer. The pressure replenishment controller controls the pressure replenishment of the hydrogen storage unit and switches between different pressure replenishment modes.

7. The pressurization system for a cryogenic high-pressure hydrogen storage system according to claim 6, characterized in that, When a main pressurization line containing a liquid hydrogen pump and a vaporizer is connected to several hydrogen storage units in a hydrogen storage system, several pressurization bypass lines are simultaneously connected from the outlet of the liquid hydrogen pump. The number of pressurization bypass lines is the same as the storage capacity of the hydrogen storage unit. The pressurization controller is configured to pressurize the hydrogen storage units that need pressurization in sequence from low to high hydrogen storage temperature.

8. The pressurization system for a cryogenic high-pressure hydrogen storage system according to claim 6, characterized in that, When each hydrogen storage unit has a corresponding main pressurization line, each main pressurization line is configured with a corresponding bypass line; The pressure replenishment controller is configured to simultaneously perform independent pressure replenishment operations on the hydrogen storage units that require pressure replenishment.

9. The pressurization system for a cryogenic high-pressure hydrogen storage system according to claim 6, 7, or 8, characterized in that, A pump solenoid valve is installed before the inlet of each liquid hydrogen pump, a pressure replenishing solenoid valve is installed before the inlet of each hydrogen storage unit, and a bypass solenoid valve is installed near the liquid hydrogen pump for each pressure replenishing bypass. The pressure replenishment controller controls the pressure replenishment of the hydrogen storage unit and switches the pressure replenishment mode by controlling the opening and closing of each solenoid valve.

10. A pressurization system for a cryogenic high-pressure hydrogen storage system according to claim 6, 7, or 8, characterized in that, The heat exchange pipeline in the middle section of the pressure replenishment bypass is a heat exchange coil; the heat exchange coil is installed inside the insulating shell of the hydrogen storage unit and wrapped around the outside of the hydrogen storage container, and the hydrogen in the heat exchange coil exchanges heat with the hydrogen in the hydrogen storage container. The hydrogen storage container is equipped with a pressure detection unit, a temperature detection unit, and an electric heating device connected to a pressure replenishment controller.

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