Liquid hydrogen energy storage system adopting solid phase cold accumulation

Abstract

The utility model provides a liquid hydrogen energy storage system adopting solid phase cold accumulation, and particularly relates to the technical field of low-temperature energy storage, which comprises a power supply conveying unit, a cold accumulation packed bed and a liquefaction supply unit, wherein the liquefaction supply unit comprises a hydrogen production device, a precooling heat exchanger, an ortho-parahydrogen converter, a final-stage heat exchanger and a liquid hydrogen storage tank; the power supply conveying unit comprises a storage module, a power supply module and a cold storage packed bed; when the liquid hydrogen is used by the power supply conveying unit, the cold energy of the liquid hydrogen is stored in the cold storage packed bed, and when the liquid hydrogen is filled into the power supply conveying unit next time, the cold energy stored in the cold storage packed bed is used for providing precooling for the liquefaction supply unit, the cold energy is recovered by the cold storage packed bed, and the hydrogen is converted into the liquid hydrogen for providing precooling. And compared with cold energy cycle power generation, the utilization rate of high-quality cold energy in a low-temperature area is higher.

Description

Technical Field

[0001] The utility model relates to the technical field of low-temperature energy storage, and in particular to a liquid hydrogen energy storage system using solid-phase cold storage. Background Art

[0002] Liquid hydrogen is gradually gaining attention as a clean and efficient energy storage technology because of its advantages such as high energy density and low transportation cost. In particular, it highlights its potential advantages in large-scale and long-distance energy storage. The liquid hydrogen energy storage system using solid-phase cold storage includes multiple modules such as water electrolysis for hydrogen production, hydrogen liquefaction, low-temperature tank storage, vehicle and ship transportation, pressurization and regasification, expansion power generation, and fuel cell power generation. Since hydrogen liquefaction requires a lower temperature and the liquefaction power consumption is relatively high, recovering the liquid hydrogen cold energy and reusing it is a key step to reduce costs and increase efficiency.

[0003] Currently, most liquid hydrogen energy storage systems that use solid-phase cold storage use heat exchangers to recover the cold energy of liquid hydrogen and provide the cold energy of liquid hydrogen to cold energy cycle power generation. However, this system is complex and difficult to regulate stably, and the cold energy power generation cycle has a limited range of cold energy recovery temperature zones. Therefore, directly using cold energy cycle power generation for cold energy recovery is inefficient.

[0004] In view of this, the present invention provides a liquid hydrogen energy storage system using solid-phase cold storage and utilizing a cold storage packed bed to recover cold energy. Utility Model Content

[0005] In order to solve the problem of low efficiency in cold energy recovery and utilization, the utility model proposes a liquid hydrogen energy storage system using solid-phase cold storage.

[0006] The utility model is achieved through the following technical solutions:

[0007] The present invention proposes a liquid hydrogen energy storage system using solid-phase cold storage, comprising a liquefaction supply unit and a power supply and delivery unit, wherein:

[0008] The liquefaction supply unit includes a hydrogen production device, a precooling heat exchanger, a normal-parahydrogen converter, a final-stage heat exchanger and a liquid hydrogen storage tank;

[0009] The power supply and delivery unit includes a storage module, a power supply module and a cold storage filling bed;

[0010] When the cold storage filled bed stores energy, one outlet end of the hydrogen production device is connected in sequence to the first heat exchange side of the pre-cooling heat exchanger, the normal-para-hydrogen converter, the first heat exchange side of the final-stage heat exchanger, the liquid hydrogen storage tank, the storage module and the bottom inlet end of the cold storage filled bed, and is connected to the power supply module from the top outlet end of the cold storage filled bed. The hydrogen in the hydrogen production device passes through the first heat exchange side of the pre-cooling heat exchanger, the normal-para-hydrogen converter, and the first heat exchange side of the final-stage heat exchanger in sequence and is converted into liquid hydrogen and enters the liquid hydrogen storage tank. The liquid hydrogen in the liquid hydrogen storage tank then enters the storage module for storage. After the power supply and delivery unit is operated, the liquid hydrogen in the storage module enters from the bottom of the cold storage filled bed and exchanges heat with the cold storage filled bed, and is converted into hydrogen and flows out from the top of the cold storage filled bed to provide hydrogen for the power supply module.

[0011] When the cold storage filled bed releases energy, the other outlet end of the hydrogen production device is connected to the inlet end at the top of the cold storage filled bed, and the other outlet end at the bottom of the cold storage filled bed is connected to the first heat exchange side inlet end of the final stage heat exchanger, and is connected in sequence to the liquid hydrogen storage tank and the storage module; the hydrogen in the hydrogen production device enters from the top of the cold storage filled bed and is pre-cooled by heat exchange with the cold storage filled bed, and then is converted into liquid hydrogen after heat exchange on the first heat exchange side of the final stage heat exchanger and enters the liquid hydrogen storage tank and the storage module for storage.

[0012] Furthermore, the cold storage filled bed includes an external insulation layer, and two guide plates and two heat insulation plates are provided in the cold storage filled bed. The two guide plates are respectively arranged at the top and bottom of the cold storage filled bed, and the two heat insulation plates are located between the two guide plates. The two guide plates and the two heat insulation plates divide the cold storage filled bed into three areas of upper, middle and lower from top to bottom and fill them with different cold storage materials in sequence.

[0013] Furthermore, the cold storage material includes lead shot, phosphor bronze wire mesh and stainless steel wire mesh, the stainless steel wire mesh fills the upper area, the phosphor bronze wire mesh fills the middle area, and the lead shot fills the lower area.

[0014] Furthermore, the power supply module includes a hydrogen steam turbine and a fuel cell stack, and the top outlet end of the cold storage filled bed is connected to the hydrogen steam turbine and the fuel cell stack in sequence.

[0015] Furthermore, the liquefaction supply unit includes a first compressor and a first expander, one end of the first compressor is connected in sequence to the second heat exchange side of the pre-cooling heat exchanger, the first expander, the second heat exchange side of the final-stage heat exchanger, the third heat exchange side of the pre-cooling heat exchanger and back to the inlet end of the first compressor, and the fourth heat exchange side of the pre-cooling heat exchanger is also connected to a nitrogen source.

[0016] Furthermore, a second compressor is provided between the storage module and the bottom inlet end of the cold storage filling bed.

[0017] Furthermore, a throttle valve is provided between the first heat exchange side of the final stage heat exchanger and the liquid hydrogen storage tank.

[0018] Furthermore, a third compressor is provided between the hydrogen production device and the first heat exchange side of the pre-cooling heat exchanger and the top inlet end of the cold storage packed bed.

[0019] Beneficial effects of the utility model:

[0020] (1) The liquid hydrogen energy storage system using solid-phase cold storage proposed in the present invention uses a cold storage filled bed to store cold energy. When liquid hydrogen is converted into hydrogen, the cold energy of the liquid hydrogen is stored in the cold storage filled bed. When liquid hydrogen is subsequently added, the hydrogen is pre-cooled by the cold energy of the cold storage filled bed for subsequent conversion into liquid hydrogen, thereby improving the utilization rate of cold energy. Compared with cold cycle power generation, the use of a cold storage filled bed for cold storage has a higher cold energy utilization rate.

[0021] (2) The liquid hydrogen energy storage system using solid-phase cold storage proposed in the present invention is filled with three materials. The cold storage filling bed is filled with lead, phosphor bronze and stainless steel at the lower, middle and upper parts respectively. The use of three different materials can match liquid hydrogen in different temperature zones and recover cold energy.

[0022] (3) The liquid hydrogen energy storage system using solid-phase cold storage proposed in the present invention adopts a wire mesh and lead shot structure to provide a larger heat exchange area under the same volume. At the same time, it can serve as an air flow distributor to promote uniform flow and heat exchange of hydrogen in the packed bed, thereby improving the overall cooling efficiency and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Provides an overall diagram of the liquid hydrogen energy storage system using solid phase cold storage for the utility model;

[0024] Figure 2 The utility model provides different cold storage materials and specific heat capacity of hydrogen for the liquid hydrogen energy storage system using solid phase cold storage;

[0025] Figure 3 The utility model provides different cold storage materials and thermal conductivity of hydrogen in the liquid hydrogen energy storage system using solid phase cold storage;

[0026] In the figure: hydrogen production device 1, third compressor 2, first compressor 3, pre-cooling heat exchanger 4, normal-parahydrogen converter 5, final-stage heat exchanger 6, first expander 7, throttle valve 8, liquid hydrogen storage tank 9, storage module 10, second compressor 11, cold storage packed bed 12, guide plate 121, heat insulation plate 122, insulation layer 123, stainless steel wire mesh 124, phosphor bronze wire mesh 125, lead shot 126, hydrogen turbine 13, fuel cell stack 14;

[0027] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0028] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0029] Please refer to Figure 1-Figure 3 The present invention proposes a liquid hydrogen energy storage system using solid-phase cold storage, comprising a liquefaction supply unit and a power supply and transmission unit, wherein:

[0030] The liquefaction supply unit includes a hydrogen production device 1, a precooling heat exchanger 4, a normal-parahydrogen converter 5, a final-stage heat exchanger 6 and a liquid hydrogen storage tank 9;

[0031] The power delivery unit includes a storage module 10, a power supply module and a cold storage filled bed 12;

[0032] When the cold storage filled bed 12 stores energy, one outlet end of the hydrogen production device 1 is connected in sequence to the first heat exchange side of the pre-cooling heat exchanger 4, the normal-parahydrogen converter 5, the first heat exchange side of the final-stage heat exchanger 6, the liquid hydrogen storage tank 9, the storage module 10 and the bottom inlet end of the cold storage filled bed 12, and is connected to the power supply module from the top outlet end of the cold storage filled bed 12. The hydrogen in the hydrogen production device 1 passes through the first heat exchange side of the pre-cooling heat exchanger 4, the normal-parahydrogen converter 5, and the first heat exchange side of the final-stage heat exchanger 6 in sequence and is converted into liquid hydrogen and enters the liquid hydrogen storage tank 9. The liquid hydrogen in the liquid hydrogen storage tank 9 then enters the storage module 10 for storage. After the power supply and delivery unit is operated, the liquid hydrogen in the storage module 10 enters from the bottom of the cold storage filled bed 12 and exchanges heat with the cold storage filled bed 12, is converted into hydrogen, and flows out from the top of the cold storage filled bed 12 to provide hydrogen for the power supply module;

[0033] When the cold storage filled bed 12 releases energy, the other outlet end of the hydrogen production device 1 is connected to the inlet end at the top of the cold storage filled bed 12, and the other outlet end at the bottom of the cold storage filled bed 12 is connected to the first heat exchange side inlet end of the final stage heat exchanger 6, and is connected in sequence to the liquid hydrogen storage tank 9 and the storage module 10; the hydrogen in the hydrogen production device 1 enters from the top of the cold storage filled bed 12 and is pre-cooled by heat exchange with the cold storage filled bed 12, and then is converted into liquid hydrogen after heat exchange on the first heat exchange side of the final stage heat exchanger 6 and enters the liquid hydrogen storage tank 9 and the storage module 10 for storage.

[0034] In this embodiment:

[0035] The precooling heat exchanger 4 is used to precool the hydrogen;

[0036] The final heat exchanger 6 is used to further convert the pre-cooled hydrogen into liquid hydrogen;

[0037] The cold storage packed bed 12 is used to recover the cold energy of hydrogen and provide cold energy for pre-cooling of liquid hydrogen;

[0038] The para-hydrogen converter 5 is filled with a para-hydrogen catalyst for completing the para-hydrogen conversion;

[0039] The storage module 10 and the liquid hydrogen storage tank 9 are used to store liquid hydrogen;

[0040] The power supply module is used for hydrogen power generation;

[0041] In a specific embodiment, reference Figure 1 The power supply module is set at the user end, the storage module 10 and the cold storage filling bed 12 can be used for on-site storage and cold storage, or they can be set on a transport vehicle, which can be transported to areas with large electricity demand or to supplement electricity during peak hours of electricity load. The liquefaction supply unit is set on the renewable energy side. When filling liquid hydrogen, the hydrogen produced by the hydrogen production device 1 is pre-cooled by the pre-cooling heat exchanger 4 and then enters the positive-secondary hydrogen converter 5 to complete the positive-secondary conversion of hydrogen, and then enters the final heat exchanger 6 to be further converted into liquid hydrogen. Liquid hydrogen Then it enters the liquid hydrogen storage tank 9 for storage to facilitate subsequent filling. When filling with liquid hydrogen, the liquid hydrogen in the liquid hydrogen storage tank 9 enters the storage module 10 on the transport vehicle for storage. After filling and transportation, when the energy storage system releases energy, the liquid hydrogen in the storage module 10 recovers cold energy through the cold storage filled bed 12, is converted into hydrogen, and enters the power supply module for power generation. Since the cold storage filled bed 12 absorbs the cold energy of the liquid hydrogen, the cold storage filled bed 12 has a certain cold capacity, that is, the cold storage filled bed 12 stores energy;

[0042] When the transport vehicle is refilled with liquid hydrogen again, since the cold storage filled bed 12 has a certain cooling capacity, when liquid hydrogen is refilled, the hydrogen generated by the hydrogen production device 1 can enter the cold storage filled bed 12 for heat exchange again, and be pre-cooled in the cold storage filled bed 12. After pre-cooling, it is converted into liquid hydrogen again through the final stage heat exchanger 6 and stored in the liquid hydrogen storage tank 9 and the storage module 10, that is, the cold storage filled bed 12 releases energy.

[0043] Furthermore, the cold storage filling bed 12 includes an external insulation layer 123. Two guide plates 121 and two thermal insulation plates 122 are provided in the cold storage filling bed 12. The two guide plates 121 are respectively arranged at the top and bottom of the cold storage filling bed, and the two thermal insulation plates are located between the two guide plates. The two guide plates 121 and the two thermal insulation plates 122 divide the cold storage filling bed 12 into three areas of upper, middle and lower from top to bottom and fill them with different cold storage materials in sequence.

[0044] In this embodiment:

[0045] The thermal insulation layer 123 is used to reduce heat leakage of the cold storage filled bed 12;

[0046] Top and bottom guide plates 121 are used to help distribute the hydrogen flow;

[0047] The heat insulation board 122 is used to reduce the internal heat exchange loss of each area;

[0048] In a specific embodiment, the guide plate 121 is arranged at the top and bottom of the cold storage filled bed 12. When storing or releasing cold, the hydrogen flow will first pass through the guide plate 121 for diversion, and the heat insulation plate 122 separates the middle area to prevent internal heat exchange. The upper, middle and lower areas of the cold storage filled bed 12 are filled with different cold storage materials. The liquid hydrogen in the storage module 10 enters from the bottom of the cold storage filled bed 12 and passes through the lower, middle and upper areas in sequence for heat exchange, and finally is converted into hydrogen and flows out from the top of the cold storage filled bed 12. Since the liquid hydrogen is converted into hydrogen from the bottom to the top, Therefore, the lower temperature of the three areas in the cold storage filled bed 12 is less than the middle temperature and less than the upper temperature. When liquid hydrogen is added for the second time, hydrogen is introduced from the top of the cold storage filled bed 12, and the hydrogen passes through the upper, middle and lower parts of the cold storage filled bed 12 in turn, gradually cooling down to complete pre-cooling. The cold energy is released from the bottom to the top of the cold storage filled bed 12 and stored in the cold storage filled bed 12, and the cold energy is absorbed from the top to the bottom to pre-cool the liquefied liquid hydrogen. The liquid hydrogen cooling capacity can be recovered in the maximum temperature range and maintained stable for a long time. At the same time, there must be heat exchange continuity, no phase change temperature limit, and the operation is simpler.

[0049] In one embodiment, the number of cold storage filling beds 12 can also be selected according to actual conditions, and can be one or more. By controlling and monitoring parameters such as temperature and flow, cold can be stored sequentially or simultaneously to improve the recovery and utilization of cold energy, and the adaptability to large-scale liquid hydrogen systems can be enhanced.

[0050] In one embodiment, the use of solid materials for cold storage is highly economical and chemically stable, and has a small heat exchange temperature range restriction. Compared with the use of rocks and the like as cold storage materials in liquid air energy storage, and the use of intermediate heat exchange fluids for cold storage and cold withdrawal, the secondary heat exchange of liquid air energy storage results in a lower round-trip efficiency of the system.

[0051] Furthermore, the cold storage material includes lead shot 126, phosphor bronze wire mesh 125 and stainless steel wire mesh 124, the stainless steel wire mesh 124 fills the upper area, the phosphor bronze wire mesh 125 fills the middle area, and the lead shot 126 fills the lower area.

[0052] In this embodiment:

[0053] Wire mesh and lead shot 126 can provide a larger heat transfer surface area;

[0054] In a specific embodiment, reference Figure 2-Figure 3As shown in Table 1, taking into account the volumetric heat capacity, thermal conductivity, and cost at low temperatures, three cold storage materials, lead, phosphor bronze, and stainless steel, are selected as the filling materials for the cold storage filled bed 12. At the same time, factors such as material processing technology, volume weight, and heat transfer area will also affect the cold storage filled bed 12. Therefore, the structure of lead shot 126, phosphor bronze wire mesh 125, and stainless steel wire mesh 124 is selected. The use of lead, phosphor bronze, and stainless steel can respectively match the cold energy recovery in the temperature ranges of approximately 24-50K, 50-120K, and 120-300K, and continuously match the wide temperature range of liquid hydrogen cold energy recovery.

[0055] Table 1 Porosity of solid cold storage materials

[0056]

[0057] Compared with the use of a single material, it is more suitable for liquid hydrogen cooling recovery. The structure of stainless steel wire mesh 124, phosphor bronze wire mesh 125 and lead shot 126 can provide a larger heat exchange area under the same volume, and can be used as an air flow distributor to promote uniform flow and heat exchange of hydrogen in the packed bed, thereby improving the overall cooling efficiency and performance.

[0058] In one embodiment, lead, phosphor bronze and stainless steel are preferred embodiments of the present invention. In specific use, other materials can also be selected according to actual needs, as long as they can match the cold energy recovery in different temperature zones.

[0059] Furthermore, the power supply module includes a hydrogen turbine 13 and a fuel cell stack 14 , and the top outlet end of the cold storage filled bed 12 is connected to the hydrogen turbine 13 and the fuel cell stack 14 in sequence.

[0060] In this embodiment:

[0061] Fuel cell stack 14 is used for hydrogen reaction to generate power

[0062] The hydrogen turbine 13 is used to recover the pressure of hydrogen;

[0063] In a specific embodiment, high-pressure hydrogen will drive the hydrogen turbine 13 to generate power, releasing the pressure potential energy maintained by compression at low temperature. After passing through the hydrogen turbine 13, the high-pressure hydrogen will be heated to a suitable temperature to facilitate subsequent entry into the fuel cell stack 14 for reaction and power generation.

[0064] Furthermore, the liquefaction supply unit includes a first compressor 3 and a first expander 7. One end of the first compressor 3 is connected in sequence to the second heat exchange side of the precooling heat exchanger 4, the first expander 7, the second heat exchange side of the final heat exchanger 6, the third heat exchange side of the precooling heat exchanger 4 and back to the inlet end of the first compressor 3. The fourth heat exchange side of the precooling heat exchanger 4 is also connected to a nitrogen source.

[0065] In this embodiment:

[0066] The first compressor 3 and the first expander 7 are used for helium refrigeration;

[0067] The nitrogen source is used to provide pre-cooling for liquid hydrogen;

[0068] In a specific embodiment, the first compressor 3, the first expander 7, the second heat exchange side and the third heat exchange side of the pre-cooling heat exchanger 4, and the second heat exchange side of the final heat exchanger 6 form a refrigeration circuit. The refrigeration circuit cools the hydrogen on the first heat exchange side of the second heat exchanger by internally cooling the internal helium, so that the hydrogen is converted into liquid hydrogen. The nitrogen source is reversely introduced into the fourth heat exchange side of the pre-cooling heat exchanger 4, and heat exchanges with the first heat exchange side, the second heat exchange side and the third heat exchange side, and transfers the cold energy to the hydrogen and helium circulation unit, providing pre-cooling for the hydrogen while providing a certain amount of cold energy for the helium circulation unit.

[0069] In one embodiment, the first compressor 3, the first expander 7, the pre-cooling heat exchanger 4 and the final stage heat exchanger 6 can also be used for other liquefaction cycles such as hydrogen refrigeration according to actual conditions.

[0070] Furthermore, a second compressor 11 is provided between the storage module 10 and the bottom inlet end of the cold storage filled bed 12 .

[0071] In this embodiment:

[0072] The second compressor 11 is used to compress cryogenic hydrogen or liquid hydrogen;

[0073] In a specific embodiment, the second compressor 11 compresses low-temperature hydrogen and liquid hydrogen, and can use smaller compression work to maintain the pressure potential energy of low-temperature hydrogen and liquid hydrogen in a low-temperature environment. When the temperature is subsequently restored, greater expansion work can be obtained, thereby increasing the power of the hydrogen turbine 13 to obtain more electricity.

[0074] Furthermore, a throttle valve 8 is provided between the first heat exchange side of the final stage heat exchanger 6 and the liquid hydrogen storage tank 9 .

[0075] In this embodiment:

[0076] The throttle valve 8 is used for throttling and reducing the pressure of liquid hydrogen;

[0077] In a specific embodiment, a throttle valve 8 is provided at the first heat exchange side outlet of the final stage heat exchanger 6 to reduce the pressure of the converted liquid hydrogen and store it in a liquid hydrogen storage tank 9 so as to facilitate the subsequent filling of liquid hydrogen into the transport vehicle.

[0078] Furthermore, a third compressor 2 is provided between the hydrogen production device 1 and the first heat exchange side of the pre-cooling heat exchanger 4 and the top inlet end of the cold storage packed bed 12 .

[0079] In this embodiment:

[0080] The third compressor 2 is used to pressurize hydrogen;

[0081] In a specific embodiment, the hydrogen is pressurized by the third compressor 2, and the high-pressure hydrogen enters the subsequent refrigeration cycle to be cooled and finally liquefied.

[0082] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A liquid hydrogen energy storage system using solid phase cold storage, characterized in that: It includes a liquefaction supply unit and a power supply transmission unit, wherein: The liquefaction supply unit includes a hydrogen production device, a precooling heat exchanger, a normal-parahydrogen converter, a final-stage heat exchanger and a liquid hydrogen storage tank; The power supply and delivery unit includes a storage module, a power supply module and a cold storage filling bed; When the cold storage filled bed stores energy, one outlet end of the hydrogen production device is sequentially connected to the first heat exchange side of the precooling heat exchanger, the normal-parahydrogen converter, the first heat exchange side of the final heat exchanger, the liquid hydrogen storage tank, the storage module and the bottom inlet end of the cold storage filled bed, and is connected to the power supply module from the top outlet end of the cold storage filled bed; When the cold storage filled bed releases energy, the other outlet end of the hydrogen production device is connected to the inlet end at the top of the cold storage filled bed, and the other outlet end at the bottom of the cold storage filled bed is connected to the first heat exchange side inlet end of the final stage heat exchanger, and is connected in sequence to the liquid hydrogen storage tank and the storage module.

2. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1 is characterized in that: The cold storage filled bed includes an external insulation layer. Two guide plates and two heat insulation plates are arranged in the cold storage filled bed. The two guide plates are respectively arranged at the top and bottom of the cold storage filled bed. The two heat insulation plates are located between the two guide plates. The two guide plates and the two heat insulation plates divide the cold storage filled bed into three areas of upper, middle and lower from top to bottom and fill them with different cold storage materials in sequence.

3. The liquid hydrogen energy storage system using solid phase cold storage according to claim 2 is characterized in that: The cold storage material includes lead shot, phosphor bronze wire mesh and stainless steel wire mesh, the stainless steel wire mesh fills the upper area, the phosphor bronze wire mesh fills the middle area, and the lead shot fills the lower area.

4. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1 is characterized in that: The power supply module includes a hydrogen steam turbine and a fuel cell stack, and the top outlet end of the cold storage filled bed is connected to the hydrogen steam turbine and the fuel cell stack in sequence.

5. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1 is characterized in that: The liquefaction supply unit includes a first compressor and a first expander, one end of the first compressor is sequentially connected to the second heat exchange side of the precooling heat exchanger, the first expander, the second heat exchange side of the final heat exchanger, the third heat exchange side of the precooling heat exchanger and back to the inlet end of the first compressor, and the fourth heat exchange side of the precooling heat exchanger is also connected to a nitrogen source.

6. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1 is characterized in that: A second compressor is also provided between the storage module and the bottom inlet end of the cold storage filled bed.

7. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1, characterized in that: A throttle valve is also provided between the first heat exchange side of the final stage heat exchanger and the liquid hydrogen storage tank.

8. The liquid hydrogen energy storage system using solid phase cold storage according to claim 1, characterized in that: A third compressor is also provided between the hydrogen production device and the first heat exchange side of the precooling heat exchanger and the top inlet end of the cold storage packed bed.

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