Liquid metal energy storage device with spiral coil pipe

Abstract

The invention belongs to the technical field of high-temperature heat storage and energy utilization, and particularly relates to a liquid metal energy storage device with a spiral coil pipe. The device comprises an energy storage tank body, an inner cylinder is arranged in the energy storage tank body, a cold fluid downcomer is installed in the inner cylinder, and the upper end of the cold fluid downcomer penetrates through a flat cover structure and is communicated with a cold fluid inlet pipe on the flat cover structure; the cold fluid downcomer is connected with the spiral coil bundle through a bend at the bottom of the inner cylinder; the other end of the spiral coil bundle is connected with a cold fluid ascending pipe; the cold fluid ascending pipe is communicated with a cold fluid outlet pipe on the flat cover structure; a through hole is formed in the side wall of the energy storage tank, a hot fluid inlet is formed outside the energy storage tank, and a hot fluid outlet is formed in a sealing head at the bottom of the energy storage tank. Through the composite energy storage medium and the innovative heat exchanger, unification of high energy density, high power density, high safety and long service life can be achieved, and the heat exchanger is suitable for large-scale, high-temperature-grade and quick-response scenes.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature thermal storage and energy utilization technology, specifically relating to a liquid metal energy storage device with a spiral coil. Background Technology

[0002] With the rapid development of renewable energy, large-scale energy storage technology has become key to solving its intermittency and volatility problems. Thermal energy storage (TES) has attracted much attention due to its advantages such as large capacity, relatively low cost, and long lifespan. Currently, molten salt is the most widely used high-temperature thermal storage medium in commercial applications. However, molten salt technology has significant bottlenecks: First, it undergoes severe thermal decomposition at operating temperatures exceeding 600℃, producing corrosive substances and limiting the improvement of system efficiency; second, molten salt is highly corrosive to common metal materials, imposing stringent requirements on the materials of storage tanks and heat exchangers, increasing system costs; third, the low thermal conductivity of molten salt limits the system's charging and discharging power and response speed.

[0003] Liquid metals (such as sodium, lead, and lead-bismuth alloys) offer significant advantages as alternative thermal storage media, including a wide operating temperature range (above 1000℃), good thermal stability, and extremely high thermal conductivity (tens of times that of molten salts), making them ideal for high-parameter, rapid-response energy storage scenarios. However, liquid metals also have drawbacks: their specific heat capacity per unit volume is typically lower than that of molten salts, resulting in a relatively low volumetric energy density for single-liquid-metal energy storage. Furthermore, while high thermal conductivity facilitates rapid heat transfer, it also easily leads to the formation of a significant temperature gradient layer within the storage tank—a transition layer between high-temperature and low-temperature regions. The presence of this layer reduces the usable efficiency and capacity of the energy storage.

[0004] To address the aforementioned issues, existing technologies have proposed the concept of adding solid fillers with high specific heat capacity to liquid metals to form composite thermal storage media. However, how to efficiently and reliably conduct heat exchange in such a complex medium with high thermal conductivity and solid-liquid two-phase structure, and effectively control the thermocline to avoid disordered heat mixing and grade degradation, remains a pressing technical challenge. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a liquid metal energy storage device with a spiral coil. Through composite energy storage medium and innovative heat exchanger, it can achieve a combination of high energy density, high power density, high safety and long life, and is suitable for large-scale, high-temperature and fast-response scenarios.

[0006] The technical solution adopted in this invention is as follows:

[0007] A liquid metal energy storage device with a spiral coil includes an energy storage tank. The bottom of the energy storage tank has a standard elliptical end cap, and the top has a detachable flat cover structure. An inner cylinder is provided inside the energy storage tank, and a cold fluid downcomer is installed inside the inner cylinder. The upper end of the cold fluid downcomer passes through the flat cover structure and communicates with a cold fluid inlet pipe on the flat cover structure. The cold fluid downcomer is connected to a spiral coil bundle at the bottom of the inner cylinder by a bend. The other end of the spiral coil bundle is connected to a cold fluid riser pipe, which communicates with a cold fluid outlet pipe on the flat cover structure. A through hole is opened in the side wall of the energy storage tank, and a hot fluid inlet is provided on the outside. A hot fluid outlet is opened on the end cap at the bottom of the energy storage tank. A spiral tube support plate is installed inside the energy storage tank. The spiral tube support strip is fixed to the spiral tube support plate, and the outer ring of the spiral tube support plate is fixed to the inner wall of the energy storage tank, while the inner ring is fixed to the outer wall of the inner cylinder.

[0008] The energy storage tank is a vertical cylindrical structure and is a pressure vessel with a height-to-diameter ratio of 2:1.

[0009] The spiral coil bundle adopts a multi-layer unequal spacing design, forming a "sparse at the top and dense at the bottom" distribution characteristic.

[0010] The spiral coil bundle consists of 36 independent spiral coil units connected in parallel. These units are arranged in 10 horizontal layers, each containing a different number of coil units.

[0011] From top to bottom, the first to third layers each have two coils, the fourth to sixth layers each have four coils, the seventh to eighth layers each have six coils, and the ninth to tenth layers each have eight coils. The coils in each layer are fixed by high-temperature resistant spiral tube support strips.

[0012] The inner surface of the spiral tube is sandblasted to enhance the heat exchange of the working fluid, and the outer surface is coated with a 50μm thick FeCrAl coating through a hot-dip galvanizing process, wherein the weight ratio of Fe:Cr:Al in the coating is 72:20:8.

[0013] Inside the energy storage tank, the cold fluid downcomer, spiral coil tube bundle, and cold fluid upcomer are integrally spirally bent and formed without weld seams between the tubes.

[0014] The spiral coils are filled with solid thermal storage medium (5). The solid thermal storage medium is a spherical bed stack or a rectangular structure formed in one piece. The high-temperature liquid thermal storage medium flows in the channel formed inside the solid thermal storage medium.

[0015] The liquid thermal storage medium and the solid thermal storage medium constitute a composite energy storage medium.

[0016] The liquid thermal storage medium is a lead-bismuth eutectic alloy with a composition of 44.5% Pb and 55.5% Bi and a melting point of 123.5℃.

[0017] The solid thermal storage medium is made of high-purity silica ceramic balls with a particle size distribution of 5-15 mm, a true density of 2.2 g / cm3, and a specific heat capacity of 1.0 kJ / (kg·K).

[0018] The volumetric filling ratio of ceramic spheres to LBE is 60%:40%.

[0019] The energy storage tank is equipped with multiple electric heating elements, each with a power of 1.5MW. The electric heating elements are protected by SiC tubes. Four high-temperature alloy pipe interfaces are set on the side wall of the energy storage tank to connect to an external high-temperature liquid metal circuit.

[0020] The energy storage tank is equipped with an external insulation layer, which is made of nanoporous silicate composite insulation material. Multiple layers of leakage monitoring sensors are arranged at different heights on the bottom and side walls of the energy storage tank. The leakage monitoring sensors are metal wire sensors based on changes in resistance or capacitance, and use an alternating electrode array.

[0021] The beneficial effects of this invention are:

[0022] (1) The present invention provides a liquid metal energy storage device with a spiral coil, which has a high operating temperature and good safety: it adopts chemically inert lead or lead-bismuth alloy, and the upper limit of operation can reach more than 650°C. There is no risk of combustion and explosion, and the safety is far higher than that of alkali metals and molten salts.

[0023] (2) The present invention provides a liquid metal energy storage device with a spiral coil, which has high energy density and power density: by introducing solid particle filler with high specific heat capacity, the volume energy density of the composite medium is significantly improved; the high thermal conductivity of liquid metal ensures extremely high charging and discharging power and fast response capability.

[0024] (3) The present invention provides a liquid metal energy storage device with a spiral coil, which effectively controls the temperature slope layer: by using the uneven arrangement strategy of "sparse on top and dense on bottom" of the spiral coil, the temperature field inside the tank is actively matched, which effectively suppresses the negative impact of the temperature slope layer and improves the quality and utilization efficiency of thermal energy.

[0025] (4) The present invention provides a liquid metal energy storage device with a spiral coil, which has a long system life and high reliability: the heat exchange surface is protected by corrosion-resistant coating technology and combined with an inert gas protection system, which fundamentally alleviates the material corrosion problem and ensures the long life and reliable operation of the device.

[0026] (5) The liquid metal energy storage device with spiral coil provided by the present invention has flexible applications: it can be used with electric heaters for grid-side energy storage, or it can be connected to external high-temperature heat sources such as industrial waste heat and nuclear energy, with a wide range of application scenarios.

[0027] (6) The present invention provides a liquid metal energy storage device with a spiral coil, which solves the problems of easy decomposition and strong corrosivity of molten salt system above 600℃ and low specific heat capacity of single liquid metal, and is suitable for large-scale, high-parameter and fast-response energy storage scenarios.

[0028] (7) The present invention provides a liquid metal energy storage device with a spiral coil. The spiral coil is arranged in a non-uniform manner and fixed by internal support bars, which optimizes the temperature field distribution inside the tank, effectively suppresses the thermocline effect, and improves the thermal energy utilization efficiency. During charging, the medium can be heated by an immersion electric heater or an external high-temperature heat source. During heat storage, the internal liquid and solid heat storage medium can be heated by high-temperature liquid metal. During discharge, the working fluid flows through the spiral coil to exchange heat with the high-temperature medium and outputs steam or heat energy. Attached Figure Description

[0029] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in describing the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments recorded in the present invention. Those skilled in the art can derive other drawings from the following drawings without any creative effort.

[0030] Figure 1 A schematic diagram of a liquid metal energy storage device with a spiral coil provided by the present invention;

[0031] In the diagram: 1. Energy storage tank; 2. Spiral tube support plate; 3. Spiral tube support bar; 4. Hot fluid flow channel; 5. Solid heat storage medium; 6. Spiral tube bundle; 7. Hot fluid outlet; 8. Inner cylinder; 9. Cold fluid downcomer; 10. Hot fluid inlet; 11. Cold fluid riser; 12. Cold fluid outlet pipe; 13. Cold fluid inlet pipe. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., refer to the orientation or positional relationship shown in the accompanying drawings, and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example:

[0036] This embodiment uses a large-scale energy storage module with a design capacity of 1100MWh as an example for illustration. This device is mainly designed for grid-scale energy storage applications and can be integrated with renewable energy power generation facilities to achieve efficient energy storage and stable output. The present invention provides a liquid metal energy storage device with a spiral coil, comprising an energy storage tank 1. The energy storage tank 1 has a vertical cylindrical structure and is a pressure vessel. Its height-to-diameter ratio is preferably 2:1. This ratio facilitates natural convection by utilizing the static pressure of the molten metal, while optimizing structural stress distribution. The bottom of the energy storage tank 1 adopts a standard elliptical end cap, and the top is a detachable flat cover structure, facilitating the installation and maintenance of internal components.

[0037] The energy storage tank 1 has an inner cylinder 8 inside, and a cold fluid downcomer 9 is installed inside the inner cylinder 8. The upper end of the cold fluid downcomer 9 passes through the flat cover structure and is connected to the cold fluid inlet pipe 13 on the flat cover structure. The cold fluid downcomer 9 is connected to the spiral coil tube bundle 6 at the bottom of the inner cylinder by bending.

[0038] The spiral coil bundle 6 adopts a multi-layer unequal spacing design, forming a distinct "sparse at the top and dense at the bottom" distribution feature;

[0039] Preferably, the spiral coil bundle 6 is composed of 36 independent spiral coil units connected in parallel. These units are arranged in 10 horizontal layers, each containing a different number of coil units. From top to bottom, layers 1-3 each have 2 coils, layers 4-6 each have 4 coils, layers 7-8 each have 6 coils, and layers 9-10 each have 8 coils. Each layer of coils is fixed by a high-temperature resistant spiral coil support strip 3 made of S31608 stainless steel, which ensures structural strength while minimizing flow resistance.

[0040] The spiral tube has an outer diameter of 38 mm, a wall thickness of 3.5 mm, a spiral diameter of 1.2 m, and a pitch of 80 mm. The total heat exchange area of ​​the coil reaches 28,500 m².

[0041] The spiral tube is made of S31608 stainless steel. The inner surface is sandblasted to enhance the heat exchange of the working fluid. The outer surface is coated with a 50μm thick FeCrAl coating through a hot-dip galvanizing process. The weight ratio of Fe:Cr:Al in this coating is 72:20:8, which has excellent resistance to liquid metal corrosion.

[0042] The other end of the spiral coil bundle 6 is connected to the cold fluid riser pipe 11, and the cold fluid riser pipe 11 is connected to the cold fluid outlet pipe 12 on the flat cover structure.

[0043] The energy storage tank 1 has a through hole on its side wall and a hot fluid inlet 10 on its exterior. The end cap at the bottom of the energy storage tank 1 has a hot fluid outlet 7. A spiral tube support plate 2 is installed inside the energy storage tank 1. The spiral tube support strip 3 is fixed to the spiral tube support plate 2. The outer ring of the spiral tube support plate 2 is fixed to the inner wall of the energy storage tank 1, and the inner ring is fixed to the outer wall of the inner cylinder 8.

[0044] Inside the energy storage tank 1, the cold fluid downcomer 9, the spiral coil bundle 6, and the cold fluid riser 11 are integrally spirally bent without welds between the tubes. The spiral coils are filled with solid heat storage medium 5, and the solid heat storage particles form a ball bed. The gaps between the balls bed form hot fluid channels, and the high-temperature liquid heat storage medium flows between the balls bed to ensure maximum heat exchange efficiency.

[0045] The liquid thermal storage medium and the solid thermal storage medium 5 constitute a composite energy storage medium.

[0046] The liquid thermal storage medium is a lead-bismuth eutectic alloy (LBE), which completely avoids the risk of explosion from alkali metals upon contact with water, ensuring extremely high safety. Its composition is 44.5% Pb and 55.5% Bi (by weight), with a melting point of 123.5℃. This alloy remains liquid within an operating temperature range of 150-750℃, exhibiting extremely low vapor pressure and excellent chemical inertness. The entire system contains approximately 18,000 tons of LBE.

[0047] The solid thermal storage medium 5 is made of high-purity silica (SiO2) ceramic spheres, which have high specific heat capacity, high melting point, good chemical stability, and low cost. Its particle size distribution is 5-15 mm, true density is 2.2 g / cm³, and specific heat capacity is 1.0 kJ / (kg·K). The volumetric filling ratio of ceramic spheres to LBE is 60%:40%, which maximizes the volumetric energy density of the entire medium while ensuring good flowability and heat transfer.

[0048] The energy storage tank 1 is equipped with multiple U-shaped electric heating elements, each with a power of 1.5MW. The electric heating elements use SiC protection tubes and are directly immersed in the composite energy storage medium, achieving a thermal efficiency of over 98%.

[0049] In another embodiment, four high-temperature alloy pipe interfaces are provided on the side wall of the energy storage tank 1, which can be connected to an external high-temperature liquid metal circuit. The interfaces employ a double mechanical seal structure to ensure reliable sealing. High-temperature liquid metal (such as sodium or lead-bismuth alloy at 700℃) flows evenly into the tank through a distributor, directly contacting the composite energy storage medium for heat exchange. Inside the energy storage tank 1, below the horizontal position of the hot fluid inlet 10, a solid heat storage medium 5 is provided. This solid heat storage medium 5 is integrally formed from high-purity silicon dioxide (SiO2), with pre-embedded rectangular hot fluid channels inside. Compared to ball-bed type solid heat storage media, it is more difficult to manufacture, but has lower flow resistance, making it suitable for scenarios with lower pump power.

[0050] The top space of the energy storage tank 1 is filled with high-purity argon gas (purity >99.999%), maintaining a slightly positive pressure state (5-10 kPa). An oxygen content monitoring system is installed inside, employing a zirconia oxygen sensor to monitor the oxygen concentration in real time. When the concentration exceeds 10 ppm, the purification process is automatically activated.

[0051] The energy storage tank 1 is externally equipped with an insulation layer made of nanoporous silicate composite insulation material, layered and wrapped, with a total thickness of 500mm. The outer protective layer is a 0.8mm thick stainless steel plate. Calculations show that at an operating temperature of 650℃, the outer surface temperature of the tank does not exceed 45℃.

[0052] The energy storage tank 1 has multiple layers of leak detection sensors arranged at different heights on its bottom and side walls. These leak detection sensors are wire sensors based on changes in resistance or capacitance, using an alternating array of electrodes to accurately locate leaks and estimate the leakage amount. The system response time is less than 0.1 seconds.

[0053] The interior of the energy storage tank 1 can be divided into three functional areas from top to bottom:

[0054] High-temperature zone: Located in the upper 2 / 3 of the tank, the medium temperature in this zone is maintained at 500-650℃ when fully charged.

[0055] Inclined temperature zone: a dynamic transition zone located in the middle of the tank, with a height of about 1-2 meters and a significant temperature gradient.

[0056] Low-temperature zone: Located at the bottom of the tank, the temperature of the medium drops to 150-200℃ when the tank is fully filled.

[0057] The working principle of this invention is as follows:

[0058] Start-up phase: First, inert gas is introduced into the energy storage tank (1) to reduce the oxygen content to below 5 ppm. Then, the hot fluid is slowly heated to above 150°C through an auxiliary heating system to ensure that the LBE is completely melted.

[0059] Charging process: When using electric heating mode, the heating power is adjusted according to the grid load. 0-4 hours: Heating at rated power, the medium temperature rises from 150℃ to 400℃; 4-8 hours: Heating at 80% power, the temperature rises from 400℃ to 580℃; 8-10 hours: Fine control at 50% power, the temperature finally reaches 650℃. The entire charging process takes 10 hours and consumes approximately 1100MWh of energy.

[0060] Heat storage process: When the heat storage mode is adopted, the high temperature liquid lead-bismuth alloy enters the energy storage tank from the hot fluid inlet, gradually raising the temperature of the solid heat storage medium from 150℃ to 650℃. The high temperature liquid lead-bismuth alloy can come from the concentrating solar collector of the solar thermal power plant and the high temperature exhaust gas of the steel smelter, etc.

[0061] Discharge process: Feedwater first enters the coil layer at the bottom of energy storage tank 1 and is preheated to near saturation. It then flows sequentially through the middle and upper coil layers, ultimately generating superheated steam at 550℃ and 15MPa. The steam output is adjustable from 50-100% of the rated load, with load adjustment completed within 30 seconds, demonstrating rapid response. Full-load discharge can last for 10 hours, with an output thermal power of 110MW. After entering the tank, the liquid metal exchanges heat with the solid thermal storage medium to store heat. When heat release is required, cold fluid is introduced into the spiral coils to carry away the heat stored in the solid thermal storage medium and the hot fluid within the tank.

[0062] Shutdown Maintenance: In the event of a planned shutdown, first stop heating or heat source input and allow the system to cool naturally to below 250°C. In the event of an emergency shutdown, the emergency cooling system can be activated to force cooling through the backup coil circuit.

[0063] The main performance indicators of this embodiment are calculated as follows:

[0064] Volumetric energy density: ~280 kWh / m³

[0065] Heat-to-heat conversion efficiency: ~95%

[0066] Daily self-discharge rate: <1%

[0067] Expected service life: >30 years

[0068] Availability: >98%

[0069] This device, through its innovative composite medium design and optimized coil layout, has successfully solved multiple technical challenges in high-temperature energy storage, such as material corrosion, thermal stratification, and energy density, providing a reliable solution for next-generation high-temperature energy storage technology.

[0070] While those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0071] Furthermore, it should be understood that although the present invention is described according to embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A liquid metal energy storage device with spiral coils, characterized in that, The energy storage tank (1) is provided with a standard elliptical head at the bottom and a detachable flat cover structure at the top. An inner cylinder (8) is arranged inside the energy storage tank (1). A cold fluid descending pipe (9) is arranged inside the inner cylinder (8). The upper end of the cold fluid descending pipe (9) penetrates through the flat cover structure and is communicated with a cold fluid inlet pipe (13) on the flat cover structure. The cold fluid descending pipe (9) is connected with a spiral coil bundle (6) through bending at the bottom of the inner cylinder. The other end of the spiral coil bundle (6) is connected with a cold fluid ascending pipe (11), which is communicated with a cold fluid outlet pipe (12) on the flat cover structure. A through hole is formed in the side wall of the energy storage tank (1), and a hot fluid inlet (10) is arranged outside the energy storage tank (1). A hot fluid outlet (7) is formed in the head at the bottom of the energy storage tank (1). A spiral pipe support plate (2) is arranged inside the energy storage tank (1). A spiral pipe support strip (3) is fixed with the spiral pipe support plate (2). The outer ring of the spiral pipe support plate (2) is fixed with the inner wall of the energy storage tank (1), and the inner ring is fixed with the outer wall of the inner cylinder (8).

2. The liquid metal energy storage device with spiral coil of claim 1, wherein, The energy storage tank (1) is a vertical cylindrical structure. The energy storage tank (1) is a pressure-bearing container, and the ratio of the height to the diameter is 2:

1.

3. The liquid metal energy storage device with spiral coil of claim 2, wherein, The spiral coil bundle (6) is designed with multiple layers and unequal distances to form a distribution feature of "upper sparse and lower dense".

4. The liquid metal energy storage device with spiral coil of claim 3, wherein, The spiral coil bundle (6) is composed of 36 independent spiral pipe units connected in parallel. These units are arranged in 10 horizontal layers, and each layer contains different numbers of coil units.

5. The liquid metal energy storage device with spiral coil of claim 4, wherein, From top to bottom, 2 coil pipes are arranged in each of the 1st-3rd layers, 4 coil pipes are arranged in each of the 4th-6th layers, 6 coil pipes are arranged in each of the 7th-8th layers, and 8 coil pipes are arranged in each of the 9th-10th layers. Each layer of coil pipes is fixed by a high-temperature-resistant spiral pipe support strip (3).

6. The liquid metal energy storage device with spiral coil of claim 5, wherein, The inner surface of the spiral pipe is sandblasted to enhance the working medium heat exchange. The outer surface is formed with a 50μm-thick FeCrAl plating layer by hot-dip plating process. The weight ratio of Fe:Cr:Al in the plating layer is 72:20:

8.

7. The liquid metal energy storage device with spiral coil of claim 6, wherein, Inside the energy storage tank (1), the cold fluid descending pipe (9), the spiral coil bundle (6) and the cold fluid ascending pipe (11) are integrally spiral-bent formed, and there is no welding seam between the pipes.

8. The liquid metal energy storage device with spiral coil of claim 7, wherein, Solid-state heat storage medium (5) is filled between the spiral coil bundles. The solid-state heat storage medium is stacked in a spherical bed or integrally formed in a rectangular structure. High-temperature liquid heat storage medium flows in the channel formed inside the solid-state heat storage medium.

9. The liquid metal energy storage device with spiral coil of claim 8, wherein, The liquid heat storage medium and the solid-state heat storage medium (5) constitute a composite energy storage medium.

10. The liquid metal energy storage device with spiral coil of claim 9, wherein, The liquid heat storage medium adopts lead-bismuth eutectic alloy with a composition of 44.5% Pb and 55.5% Bi and a melting point of 123.5℃.

11. The liquid metal energy storage device with spiral coil of claim 10, wherein, The solid heat storage medium (5) adopts high-purity silicon oxide ceramic balls with a particle size distribution of 5-15 mm, a true density of 2.2 g / cm 3 , and a specific heat capacity of 1.0 kJ / (kg·K).

12. The liquid metal energy storage device with spiral coil of claim 11, wherein, The volume filling ratio of ceramic balls to LBE is 60%:40%.

13. The liquid metal energy storage device with spiral coil of claim 12, wherein, A plurality of electric heating elements are arranged inside the energy storage tank (1), each with a power of 1.5MW. The electric heating elements are provided with SiC protection pipes. Four high-temperature alloy pipe interfaces are arranged on the side wall of the energy storage tank (1) to connect the external high-temperature liquid metal loop.

14. The liquid metal energy storage device with spiral coil of claim 13, wherein, The energy storage tank body (1) is externally provided with a heat preservation layer, the heat preservation layer adopts a nano microporous silicate composite heat preservation material; a plurality of layers of leakage monitoring sensors are arranged at different heights of the bottom and the side wall of the energy storage tank body (1), the leakage monitoring sensors are metal wire sensors based on resistance or capacitance changes, and an electrode array in staggered arrangement is adopted.

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