An electrically heated solid heat storage unit device

Abstract

The application discloses an electric heating solid heat storage unit device, and relates to the technical field of energy storage. The electric heating solid heat storage unit device comprises solid heat storage particles, a metal shell, an electric heating assembly, an internal fin assembly and an external fin assembly. The solid heat storage particles are filled in the interior of the metal shell. The electric heating assembly is embedded in the interior of the solid heat storage particles and used for converting electric energy into heat energy and heating the solid heat storage particles. The internal fin assembly is arranged on the inner wall of the metal shell and extends to the interior of the solid heat storage particles. The external fin assembly is arranged on the outer wall of the metal shell. The application can realize fast power response, efficient heat storage and heat release and stable output of high-temperature steam or high-temperature gas in the deep peak regulation scene of the power system.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically, to an electrically heated solid thermal energy storage unit device. Background Technology

[0002] With the rapid development of new energy power generation technologies, the grid connection ratio of renewable energy sources such as wind power and solar power continues to increase, making thermal power's role as a basic peak-shaving power source increasingly prominent. Currently, the power system faces increasingly severe demands for deep peak shaving. The contradiction between the intermittency and volatility of new energy power generation and the rigid demand of the grid load is constantly intensifying, leading to frequent grid frequency fluctuations and wind and solar curtailment, which seriously affects the stable operation of the power system and energy utilization efficiency.

[0003] Thermal energy storage systems, as a key technology for solving the problem of deep peak shaving in power systems, can convert and store electrical and thermal energy. During periods of low grid load, excess electrical energy is converted into stored thermal energy, while during peak load periods, the thermal energy is released and converted into electrical energy or directly supplied to industrial applications, effectively balancing grid supply and demand. Solid thermal energy storage technology, with its advantages of widely available materials, high safety, no leakage risk, and long service life, has become the preferred technology for thermal energy storage systems.

[0004] Existing solid thermal energy storage devices mostly rely on waste heat recovery or indirect heating methods, which suffer from drawbacks such as low heat transfer efficiency, slow thermal energy storage response speed, and insufficient temperature control accuracy, making them difficult to adapt to the dynamic thermal energy storage needs of thermal power, wind power, and photovoltaic power. At the same time, the heat transfer structure design of existing devices is unreasonable, failing to fully utilize the advantages of finned heat transfer enhancement, resulting in a lag in heat transfer of solid thermal energy storage particles, which cannot quickly realize the conversion and release of electrical energy into thermal energy, making it difficult to meet the high efficiency and rapid response requirements of deep peak shaving for thermal energy storage systems. In addition, the heat output form of existing devices is singular, unable to stably provide high-temperature steam or high-temperature gas, limiting their industrial application scenarios and failing to fully realize the comprehensive value of thermal energy storage systems. Summary of the Invention

[0005] This application provides an electrically heated solid thermal energy storage unit device, which aims to solve the supply and demand imbalance problem caused by deep peak shaving of the power system, provide a new type of thermal energy storage system with high efficiency and fast response for thermal power, wind power and photovoltaic power, and at the same time achieve stable output of high temperature steam or high temperature gas, thus expanding the application scenarios of thermal energy storage devices.

[0006] The embodiments of the present invention are implemented as follows: This application provides an electrically heated solid thermal storage unit device, comprising: Solid thermal storage particles; A metal casing, wherein the solid heat storage particles are filled inside the metal casing; An electric heating component, embedded inside the solid thermal storage particles, is used to convert electrical energy into heat energy and heat the solid thermal storage particles; An internal fin assembly is disposed on the inner wall of the metal shell and extends into the interior of the solid heat storage particles; An external fin assembly is disposed on the outer wall of the metal housing.

[0007] In some embodiments of the present invention, the above-mentioned solid thermal storage particles include doped and modified aluminum oxide particles, wherein the particle size of the aluminum oxide particles is 0.5 mm to 5 mm, and the doping material of the aluminum oxide particles is selected from one of the following groups: Carbon powder or metal powder suitable for environments ranging from 550℃ to 1000℃, with a doping ratio of 5wt% to 15wt%; Phase change thermal storage molten salt suitable for environments ranging from 200℃ to 550℃; High-temperature heat transfer oil suitable for environments below 300°C.

[0008] In some embodiments of the present invention, the above-mentioned internal fin assembly includes a plurality of first fins arranged in parallel at intervals. The thickness of the first fins is 1.5mm to 2mm, the height is 50mm to 80mm, the spacing between adjacent first fins is 30mm to 50mm, and the first fins are fixedly connected to the metal shell.

[0009] In some embodiments of the present invention, the external fin assembly includes a plurality of second fins, which are arranged spirally or in parallel around the outer wall of the metal shell. The thickness of the second fins is 1.0 mm to 1.5 mm, the height is 20 mm to 30 mm, the spacing between adjacent second fins is 10 mm to 20 mm, and the second fins are fixedly connected to the metal shell.

[0010] In some embodiments of the present invention, the materials of the internal fin assembly and the external fin assembly are configured according to the ambient temperature of use as follows: When the ambient temperature is below 400℃, it is made of carbon steel. When the ambient temperature is between 400℃ and 600℃, it is made of stainless steel. When the ambient temperature is above 600℃, the material is tungsten alloy or nickel-based alloy with an anti-oxidation coating sprayed on the surface.

[0011] In some embodiments of the present invention, the above-mentioned electric heating component includes a resistance wire and a high-temperature resistant wire. The resistance wire is spirally arranged inside the solid heat storage particles. One end of the high-temperature resistant wire is connected to the resistance wire, and the other end extends out of the metal shell for connecting to an external power supply device. A high-temperature resistant seal is provided at the connection between the high-temperature resistant wire and the metal shell.

[0012] In some embodiments of the present invention, the resistance wire is a nickel-chromium alloy resistance wire with a diameter of 1.0 mm to 1.5 mm and a spiral diameter of 10 mm to 15 mm, and the high-temperature resistant wire is a high-temperature resistant ceramic wire.

[0013] In some embodiments of the present invention, a temperature control sensor is also included, which is embedded inside the solid thermal storage particles and is used to detect the temperature of the solid thermal storage particles.

[0014] In some embodiments of the present invention, a vacuum pumping interface is also included, which is disposed on the metal housing and is used to connect an external vacuum pumping device to evacuate the inside of the metal housing.

[0015] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: 1. This invention uses an electrically heated solid thermal energy storage unit as its core architecture. Through an electric heating component, electrical energy is directly converted into heat energy and stored in solid thermal energy storage particles. This eliminates the lengthy heat transfer path through multiple media in traditional waste heat recovery or indirect heating methods, fundamentally eliminating heat loss and response delay in intermediate heat exchange stages. The instantaneous power generation characteristic of the electric heating component enables the device to respond quickly to grid dispatch commands. Simultaneously, the low thermal resistance heat conduction network formed by the internal finned components extending into the solid thermal energy storage particles ensures rapid and uniform heat distribution within the storage body. This significantly improves the temperature field uniformity and adjustability accuracy of the thermal energy storage unit compared to existing devices relying on indirect heating. Therefore, this invention can rapidly store excess electrical energy during periods of low grid load and quickly release heat energy during peak load periods. It precisely adapts to the stringent requirements of response speed and temperature control accuracy in dynamic thermal energy storage scenarios such as deep peak shaving of thermal power and smoothing of power fluctuations in wind and solar power, effectively balancing the power system's supply and demand imbalance and improving grid stability and renewable energy absorption capacity.

[0016] 2. This invention features internal and external fin assemblies on the inner and outer walls of the metal casing, respectively, forming a dual-sided synergistic heat transfer architecture with enhanced internal heat transfer and enhanced external heat transfer. The internal fin assembly extends from the inner wall of the casing into the solid heat storage particles, significantly increasing the effective contact area between the metal casing and the heat storage particles. This creates a continuous, low-thermal-resistance heat-conducting framework for heat transfer from the electric heating component to the depths of the heat storage particles, effectively overcoming the heat transfer lag caused by point-contact heat transfer between solid particles. This significantly improves the heating speed and temperature response rate of the heat storage unit. The external fin assembly significantly increases the effective heat transfer area between the metal casing and the heat exchange medium flowing through it, improving the thermal energy output efficiency of the heat storage unit and ensuring stable output of high-temperature steam or gas in industrial applications to meet medium- to high-grade heat energy requirements.

[0017] 3. This invention uses solid thermal storage particles as the thermal storage medium. These materials are widely available, inexpensive, and have a high thermal density. Furthermore, they remain in a solid phase throughout the thermal storage and release cycles, eliminating the need for the sealing and leak-proof structures and complex volume compensation mechanisms required for phase change materials. This fundamentally eliminates the inherent leakage risks and corrosion problems of liquid-phase thermal storage media such as molten salt or heat transfer oil under high-temperature and high-pressure conditions. The high chemical and thermal cycling stability of the solid particles enables the device to adapt to long-term, frequent deep peak-shaving thermal storage and release cycle requirements, significantly extending the device's service life and reducing the operation and maintenance costs and safety hazards of the thermal storage system.

[0018] 4. This invention integrates solid thermal storage particles, electric heating components, internal finned components, and external finned components into a fully functional, standardized, and independent thermal storage unit. The overall structure is compact and rationally laid out, allowing a single thermal storage unit to independently complete the entire process of electrical and thermal energy conversion, thermal energy storage, and thermal energy release. Multiple thermal storage units can be flexibly combined in parallel for capacity expansion or in series for heating, based on actual thermal power and capacity requirements, forming a large-scale thermal storage system. This system adapts to the differentiated needs of thermal power, wind power, and photovoltaic projects with varying installed capacities, exhibiting strong versatility and scalability. This modular design facilitates standardized mass production in factories to reduce costs, and also allows for rapid on-site deployment and flexible expansion, providing reliable technical support for the stable operation of new energy power generation systems and the large-scale promotion of thermal storage facilities. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0021] Icons: 1-Metal casing; 2-Solid heat storage particles; 3-Resistance wire; 4-First fin; 5-Second fin; 6-High-temperature seal; 7-High-temperature resistant wire. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] Example Please refer to Figure 1 This embodiment provides an electrically heated solid thermal storage unit device, comprising: solid thermal storage particles 2, a metal shell 1, an electric heating assembly, an internal fin assembly, and an external fin assembly. The metal shell 1 forms a sealed thermal storage cavity, which is filled with the solid thermal storage particles 2. The metal shell 1 can be a cuboid or cylindrical structure, preferably made of high-temperature resistant stainless steel (such as 310S stainless steel), and its wall thickness can be selected according to the operating temperature and pressure rating, preferably 3mm to 5mm, to ensure sufficient structural strength and sealing performance under high-temperature conditions. The electric heating assembly is embedded inside the solid thermal storage particles 2, evenly distributed within the thermal storage cavity, with both ends extending out of the metal shell 1 and electrically connected to an external power supply device to directly convert electrical energy into heat energy to heat the solid thermal storage particles 2. The internal fin assembly is disposed on the inner wall of the metal shell 1 and extends from the inner wall toward the interior of the solid thermal storage particles 2, forming multiple heat-conducting fin structures. The internal fin assembly is preferably made of a metal material with high thermal conductivity (such as pure copper) and is fixedly connected to or integrally formed with the metal shell 1. The aforementioned external fin assembly is disposed on the outer wall of the metal shell 1 and is evenly arranged along the outer wall of the shell to form multiple heat dissipation fin structures. The external fin assembly is preferably made of a metal material with high thermal conductivity (such as aluminum alloy) and is fixedly connected to the metal shell 1.

[0025] In this embodiment, the electrically heated solid thermal storage unit is housed within a casing, with a fluid channel formed between the metal casing and the outer casing. This fluid channel is connected to a heat exchange interface, which includes a medium input interface and a medium output interface, both communicating with the fluid channel. Furthermore, an external heat exchange pipeline is included. This external heat exchange pipeline is mounted on the metal casing 1, penetrates the wall of the metal casing 1, and circulates with the internal thermal storage cavity, serving as an input channel for the medium to be heated and an output channel for the heated medium.

[0026] The working process of the electrically heated solid thermal storage unit device in this embodiment includes a thermal storage stage and a thermal release stage: The first stage is the thermal storage phase: When the grid load is low or there is excess electricity, the external power supply device powers the electric heating component. The electric heating component converts electrical energy into heat energy, its own temperature rises rapidly, and it transfers the heat to the surrounding solid thermal storage particles 2 through thermal radiation and thermal conduction. The internal finned assembly extends from the inner wall of the shell into the interior of the solid thermal storage particles 2, forming a low thermal resistance heat conduction path, efficiently conducting heat to the thermal storage particle area away from the heating component, so that the temperature of the solid thermal storage particles 2 in the entire thermal storage cavity rises uniformly, completing the conversion and storage of electrical energy into thermal energy. At the same time, the high-temperature heat exchange medium enters the metal shell 1 through the external heat exchange pipeline, and transfers heat to the metal shell 1, further storing the heat in the solid thermal storage particles 2.

[0027] The second stage is the heat release phase: During peak grid loads or when there is a demand for heat energy, a low-temperature medium (such as water or air) in the external heat exchange pipeline is introduced into the fluid channel outside the metal casing 1 through the heat exchange interface. The low-temperature medium flows through the gaps between the high-temperature solid heat storage particles 2, and indirectly exchanges heat with the solid heat storage particles 2 through the external fin assembly. After absorbing heat, it heats up to the set temperature, forming a high-temperature medium, which is then output to the external heat exchange pipeline through the heat exchange interface to supply industrial users or subsequent energy conversion equipment. The external fin assembly increases the heat dissipation area during the heat release process, which helps to improve the thermal response speed in scenarios requiring rapid cooling or precise temperature control.

[0028] In the above process, the electric heating component operates based on the Joule effect. When alternating or direct current passes through the resistive element, electrical energy is converted into internal energy, causing the electric heating component to heat up to the set temperature. The electric heating component is in direct contact with the solid heat storage particles 2. Heat is transferred to the interior of the heat storage body through two pathways: point contact heat conduction between solid particles and air conduction between particles. Compared to indirect heating methods that rely on intermediate media (such as heat transfer oil or molten salt), the instantaneous power generation characteristic of the electric heating component eliminates heat loss in intermediate heat exchange stages, enabling the device to make rapid power responses to grid dispatch commands. Meanwhile, the contact between the aforementioned solid thermal storage particles 2 is point contact, resulting in a limited contact area and a low equivalent thermal conductivity between the particles, making it difficult for heat to be quickly transferred from the heating source to the far end of the thermal storage body. The internal fin assembly extends from the inner wall of the metal shell 1 into the interior of the solid thermal storage particles 2, forming a continuous, highly thermally conductive metal skeleton within the thermal storage cavity. This significantly increases the effective contact area between the metal wall and the thermal storage particles, constructing a low-thermal-resistance thermal conductivity network and effectively overcoming the heat transfer lag problem caused by point contact heat transfer between particles. Similarly, the external fin assembly increases the effective heat transfer area between the outer wall of the metal shell 1 and the external heat exchange medium. According to Newton's cooling formula (Q = h·A·ΔT), the increase in heat transfer area A directly increases the heat transfer capacity Q, thereby improving the thermal energy output efficiency.

[0029] In addition, the above-mentioned heat exchange interface can also adopt the direct heating type, in which the low-temperature medium (water or air) is directly introduced into the metal shell 1 and directly contacts the high-temperature solid heat storage particles 2 for heat exchange. Compared with the indirect heat exchange structure, the thermal resistance of the metal wall is omitted, the heat transfer coefficient is higher, the thermal response speed is faster, and high-temperature steam or high-temperature gas can be output quickly.

[0030] This embodiment uses an electrically heated solid thermal energy storage unit as its core architecture. Electrical energy is directly converted into heat energy through an electric heating component and stored within the solid thermal energy storage particles 2. This eliminates the lengthy heat transfer path through multiple media in traditional waste heat recovery or indirect heating methods, fundamentally eliminating heat loss and response delay in intermediate heat exchange stages. The electric heating component can generate heat instantly upon power supply, enabling the device to quickly respond to power grid dispatch commands. Simultaneously, the internal finned components extend into the solid thermal energy storage particles 2, forming a low thermal resistance heat conduction network that ensures rapid and uniform heat diffusion within the storage body. Compared to existing devices relying on indirect heating, the temperature field uniformity and regulation accuracy of the thermal energy storage unit in this embodiment are effectively improved. Based on this structure, this invention can quickly store excess electrical energy during periods of low grid load and rapidly release heat energy during periods of high load. It can precisely adapt to the stringent requirements of response speed and temperature control accuracy in dynamic thermal energy storage scenarios such as deep peak shaving of thermal power and smoothing of power fluctuations in wind and solar power, effectively balancing the power system's supply and demand imbalance and improving grid stability and renewable energy absorption capacity.

[0031] Meanwhile, in this embodiment, internal fin assemblies and external fin assemblies are respectively provided on the inner and outer walls of the metal shell 1, constructing a dual-sided collaborative heat transfer architecture of "internal enhanced induction and external enhanced outduction". The internal fin assembly extends from the inner wall of the shell into the interior of the solid heat storage particles 2, significantly increasing the effective contact area between the metal shell 1 and the heat storage particles. This creates a continuous low thermal resistance heat-conducting framework for heat conduction from the electric heating component to the depth of the heat storage particles, effectively solving the problem of heat transfer lag caused by relying solely on point contact heat transfer between solid particles, and significantly improving the heating speed and temperature response rate of the heat storage unit. The external fin assembly significantly increases the effective heat exchange area between the metal shell 1 and the external heat exchange medium flowing through it, improving the thermal energy output efficiency of the heat storage unit. This ensures that the device can stably output high-temperature steam or high-temperature gas in industrial applications, meeting the needs of medium- and high-grade thermal energy.

[0032] Furthermore, this embodiment uses solid thermal storage particles 2 as the thermal storage medium. This type of material is widely available, inexpensive, and has a high thermal density. It maintains a solid phase throughout the thermal storage and release cycles, eliminating the need for the sealing and leak-proof structures and complex volume compensation mechanisms required for phase change materials. This fundamentally eliminates the inherent leakage risks and corrosion problems of liquid thermal storage media such as molten salt and heat transfer oil under high-temperature and high-pressure conditions. Solid particles possess excellent chemical and thermal cycling stability, allowing the device to adapt to long-term, frequent deep peak-shaving thermal storage and release cycles, significantly extending the device's service life and reducing the operation and maintenance costs and safety hazards of the thermal storage system. Simultaneously, the heat exchange interface allows the thermal storage unit to flexibly output various forms of heat energy, such as high-temperature steam and high-temperature gas, adapting to the differentiated heat demand in various scenarios such as industrial production, district heating, and waste heat replacement, effectively expanding the comprehensive application value of the thermal storage device.

[0033] Finally, this embodiment integrates the solid thermal storage particles 2, the electric heating assembly, the internal fin assembly, and the external fin assembly into a fully functional, standardized, independent thermal storage unit. The device has a compact overall structure and a rational layout; a single thermal storage unit can independently complete the entire process of electrical energy to thermal energy conversion, thermal energy storage, and thermal energy release. Multiple thermal storage units can be flexibly combined through heat exchange interfaces, using parallel expansion or series heating methods according to actual thermal power and capacity requirements, to form a large-scale thermal storage system. This system adapts to the differentiated needs of thermal power, wind power, and photovoltaic projects with different installed capacities, exhibiting strong versatility and scalability. This modular design facilitates standardized mass production in factories to reduce costs, and also allows for rapid on-site deployment and flexible expansion, providing reliable technical support for the stable operation of new energy power generation systems and the large-scale promotion of thermal storage facilities.

[0034] Optionally, in this embodiment, the solid thermal storage particles 2 are doped and modified aluminum oxide particles with a particle size of 0.5 mm to 5 mm. The doping material of the aluminum oxide particles is selected from one of the following groups: carbon powder or metal powder suitable for environments of 550°C to 1000°C, with a doping ratio of 5 wt% to 15 wt%; phase change thermal storage molten salt suitable for environments of 200°C to 550°C; and high-temperature heat transfer oil suitable for environments below 300°C. It is worth noting that in other embodiments, the solid thermal storage particles 2 can also be made of silicon dioxide materials such as sand.

[0035] The aforementioned aluminum oxide (Al₂O₃) has a specific heat capacity of approximately 0.88 kJ / (kg·K) and a density of approximately 3.9 g / cm³. It exhibits excellent chemical and thermal cycling stability within a temperature range below 1000℃ and will not undergo significant high-temperature chemical reactions with the electric heating components or the metal casing 1. The particle size is controlled within the range of 0.5 mm to 5 mm, balancing the interparticle porosity (ensuring medium flowability) and the internal thermal conductivity (ensuring the heat storage / release rate). As a heat storage matrix material, aluminum oxide particles possess advantages such as high melting point, high specific heat capacity, high chemical stability, and wide availability. Their particle size of 0.5 mm to 5 mm balances medium flowability and heat storage / release rate, enabling the device to maintain stable heat storage performance and structural integrity during long-term, frequent heat storage and release cycles. The design principle of using different doping materials in different temperature zones is as follows: In the high temperature range (550℃~1000℃), the proportion of heat transfer by thermal radiation in the heat storage body increases significantly, and the high radiation absorption rate and high thermal conductivity of carbon powder / metal powder can synergistically enhance radiation absorption and conduction heat transfer; In the medium temperature range (200℃~550℃), the latent heat storage of phase change heat storage molten salt can greatly improve the heat storage density, making up for the relatively low sensible heat storage density of alumina; In the low temperature range (below 300℃), the liquid phase heat transfer of high temperature heat transfer oil can make up for the problem of low heat transfer efficiency of point contact between solid particles.

[0036] Therefore, this embodiment achieves optimal matching between the thermophysical properties of the heat storage particles and the operating temperature range of the device by employing different doping modification schemes in different temperature ranges: in the high-temperature range, the enhanced thermal conductivity and radiation absorption effects of carbon powder / metal powder are used to improve the heating rate and heat storage efficiency; in the medium-temperature range, the latent heat storage of phase change molten salt is used to improve the heat storage density; and in the low-temperature range, the liquid phase heat transfer of heat transfer oil is used to improve temperature uniformity. This segmented doping design allows the same device architecture to adapt to diverse application scenarios across a wide temperature range (below 200℃ to 1000℃), significantly expanding the applicability of the device.

[0037] Preferably, in this embodiment, the aforementioned internal fin assembly includes multiple parallel-arranged first fins 4. The thickness of the first fins 4 is 1.5mm to 2mm, the height is 50mm to 80mm, and the spacing between adjacent first fins 4 is 30mm to 50mm. The first fins 4 are fixedly connected to the metal shell 1. The multiple parallel-arranged first fins 4 extend from the inner wall of the shell into the interior of the heat storage body, significantly increasing the effective contact area between the metal shell 1 and the solid heat storage particles 2. This constructs a continuous, low-thermal-resistance thermally conductive framework for heat conduction to the depth of the heat storage body, effectively overcoming the problem of heat transfer lag caused by point contact heat transfer between solid particles. At the same time, the parameter combination of the first fins 4 having a thickness of 1.5mm to 2mm, a height of 50mm to 80mm, and a spacing of 30mm to 50mm achieves a reasonable balance between fin structural strength, thermally conductive cross-sectional area, heat storage space utilization, and temperature uniformity, ensuring rapid heat conduction capability while avoiding excessive fin encroachment on the heat storage space.

[0038] It is worth noting that the fixed connection (welding or integral molding) between the first fin 4 and the metal shell 1 ensures the continuity of the heat conduction interface and the low thermal resistance characteristics, enabling heat to be efficiently conducted between the shell and the fin.

[0039] Preferably, in this embodiment, the external fin assembly includes a plurality of second fins 5, which are arranged spirally or in parallel along the outer wall of the metal shell 1. The thickness of the second fins 5 is 1.0 mm to 1.5 mm, the height is 20 mm to 30 mm, the spacing between adjacent second fins 5 is 10 mm to 20 mm, and the second fins 5 are fixedly connected to the metal shell 1.

[0040] During the heat release phase, the inner wall of the metal shell 1 absorbs heat from inside the heat storage body, which is then conducted through the shell wall thickness to the outer wall and then to the second fin 5. When the external heat exchange medium (such as water, air, or process gas) flows across the outer wall of the shell and the surface of the second fin 5, it undergoes convective heat exchange with the fins and the shell, absorbing heat and increasing its temperature. The second fin 5 increases the heat exchange area between the shell and the outside, allowing more heat to be efficiently transferred to the external heat exchange medium. When the external heat exchange medium is a gas with a low flow rate (such as in a natural convection heat dissipation scenario), the second fin 5 mainly relies on increasing the heat dissipation area to increase the heat dissipation. When the external heat exchange medium is a liquid or a high-speed airflow (such as in a forced convection heat dissipation scenario), the second fin 5, while increasing the heat exchange area, also disturbs the flow medium—the boundary layer on the fin surface is constantly disrupted and rebuilt due to the obstruction of the fins, thereby increasing the convective heat transfer coefficient.

[0041] In some embodiments of this example, when arranged in a spiral, the second fin 5 is continuously spiraled around the outer wall of the shell, which is suitable for a cylindrical metal shell 1 and helps to guide the external heat exchange medium to flow along the spiral path, thus extending the heat exchange path and contact time. In other embodiments of this example, when arranged in parallel, multiple second fins 5 are spaced apart along the length of the shell, suitable for cuboid metal shells 1, and also for cylindrical shells (i.e., annular fins arranged parallel along the axial direction). The aforementioned second fins 5 are fixedly connected to the outer wall of the metal shell 1, preferably by welding (such as resistance welding or brazing), to ensure a good metallurgical bond between the fin root and the outer wall of the shell, reducing contact thermal resistance. After welding, the weld joints should be ground and surface-treated to remove the oxide layer and weld slag to ensure the thermal conductivity between the fins and the shell.

[0042] Furthermore, in this embodiment, the materials of the aforementioned internal fin assembly and external fin assembly are configured according to the ambient temperature as follows: when the ambient temperature is below 400°C, they are made of carbon steel; when the ambient temperature is between 400°C and 600°C, they are made of stainless steel; and when the ambient temperature is above 600°C, they are made of tungsten alloy or nickel-based alloy with an anti-oxidation coating on the surface.

[0043] The high-temperature oxidation resistance and high-temperature strength of metallic materials exhibit significant differences with temperature. Below 400℃, carbon steel has a low surface oxidation rate, and the oxide scale is dense and self-protective; however, when the temperature exceeds 400℃, the oxidation rate of carbon steel accelerates sharply, the oxide scale thickens and becomes loose and peels off, and the transformation of ferrite to austenite may lead to dimensional instability.

[0044] Stainless steel (especially austenitic stainless steel) contains high levels of Cr and Ni, which allows a dense Cr2O3 protective film to form on its surface within the temperature range of 400℃ to 600℃. This film effectively blocks oxygen diffusion, resulting in an oxidation rate far lower than that of carbon steel. Simultaneously, austenitic stainless steel exhibits high creep strength and endurance strength within this temperature range, enabling it to withstand the thermal stress and mechanical loads on the fins at high temperatures.

[0045] When the operating temperature exceeds 600℃, even 310S stainless steel begins to show a significant acceleration in oxidation rate, and its high-temperature strength decreases markedly. Tungsten alloys and nickel-based alloys have higher melting points and excellent high-temperature strength, but their oxidation resistance is relatively insufficient—the oxides (WO3 or NiO) formed on the surface at high temperatures are loose and porous, lacking protective properties. After spraying an anti-oxidation coating (such as an aluminide coating or MCrAlY coating), the Al or Cr elements in the coating preferentially oxidize at high temperatures, forming a dense, continuous, and well-bonded Al2O3 or Cr2O3 protective film. This effectively blocks the diffusion of oxygen into the substrate, reducing the oxidation rate of the substrate by 1 to 2 orders of magnitude, thereby protecting the fin substrate from high-temperature oxidation failure.

[0046] Thus, by selecting materials in a segmented manner according to the operating temperature of the device, the material properties of the finned assembly are optimally matched with the actual service conditions of the device: carbon steel is used in the low temperature section, balancing performance and cost; stainless steel is used in the medium temperature section, ensuring high-temperature oxidation resistance and structural strength; and tungsten alloy or nickel-based alloy with surface anti-oxidation coating is used in the high temperature section, ensuring long-term service reliability under extreme high-temperature conditions.

[0047] In some embodiments of this example, the electric heating assembly includes a resistance wire 3 and a high-temperature resistant wire 7. The resistance wire 3 is spirally arranged inside the solid heat storage particles 2. One end of the high-temperature resistant wire 7 is connected to the resistance wire 3, and the other end extends through the metal shell 1 for connecting to an external power supply device. A high-temperature resistant seal 6 is provided at the connection between the high-temperature resistant wire 7 and the metal shell 1. The spiral arrangement of the resistance wire 3 inside the solid heat storage particles 2 increases the contact area and heat radiation area with the heat storage particles, making the heat distribution in the heat storage body more uniform. At the same time, it facilitates the arrangement of a sufficiently long resistance wire 3 in a limited space to achieve the required heating power. The high-temperature resistant wire 7 penetrates the metal shell 1, realizing a reliable electrical connection between the internal heating element and the external power supply device. The high-temperature resistant seal 6 ensures the airtightness of the wire penetration point, preventing high-temperature oxidation and gas leakage, and ensuring the safety and reliability of the device under long-term high-temperature service conditions.

[0048] Furthermore, in this embodiment, the resistance wire 3 is a nickel-chromium alloy resistance wire 3 with a diameter of 1.0mm to 1.5mm and a spiral diameter of 10mm to 15mm, and the high-temperature resistant wire 7 is a high-temperature resistant ceramic wire. The nickel-chromium alloy resistance wire 3 has high resistivity, a low temperature coefficient of resistance, and excellent high-temperature oxidation resistance, enabling it to provide stable and controllable heating power over a wide temperature range, thus extending the service life of the electric heating assembly. The parameter combination of a resistance wire diameter of 1.0mm to 1.5mm and a spiral diameter of 10mm to 15mm in this embodiment achieves a harmonious balance between resistance per unit length, structural strength, and uniform spatial distribution. The use of a high-temperature resistant ceramic wire in this embodiment ensures electrical insulation safety in high-temperature penetration areas, avoiding short circuits and safety accidents caused by insulation failure, and improving the operational reliability of the device under high-temperature conditions.

[0049] This embodiment also includes a temperature control sensor, which is embedded inside the solid thermal storage particles 2 and is used to detect the temperature of the solid thermal storage particles 2.

[0050] During device operation, temperature control sensors collect temperature signals from the solid thermal storage particles 2 in real time and convert these signals into electrical signals (thermocouples output thermoelectric potential signals, and resistance thermometers output resistance signals), which are then transmitted to an external controller via a signal transmission line. Upon receiving the temperature signal, the controller compares it with a preset target thermal storage temperature or a heat release temperature threshold. During the thermal storage phase, when the detected temperature reaches the target thermal storage temperature, the controller outputs a power-off command to cut off the power supply to the electric heating components, preventing overheating of the thermal storage body. During the heat release phase, when the detected temperature drops to the heat release termination temperature, the controller outputs an adjustment command (such as closing the medium input valve or reducing the medium flow rate) to prevent excessive heat release from the thermal storage body. When multiple temperature control sensors are arranged in different locations, the controller also compares and analyzes the temperatures at each measurement point, monitors the temperature uniformity within the thermal storage cavity in real time, and adjusts the power output of the electric heating components or the flow rate distribution of the external heat exchange medium according to the temperature distribution.

[0051] Thus, the aforementioned temperature control sensors are embedded inside the solid thermal storage particles 2 to detect the temperature of the thermal storage body in real time, providing accurate temperature feedback signals to the controller. This enables the device to accurately control the thermal storage temperature during the thermal storage phase and precisely regulate the output temperature during the heat release phase. The arrangement of multiple temperature control sensors in different locations gives the device the ability to monitor the temperature field, enabling real-time assessment of the temperature uniformity of the thermal storage body. This provides a data basis for optimizing the thermal storage strategy, further improving the device's temperature control accuracy and thermal storage efficiency.

[0052] This embodiment also includes a vacuum extraction port, located on the metal casing 1, for connecting an external vacuum device to evacuate the interior of the metal casing 1. During initial installation or periodic maintenance, the piping of the external vacuum device is connected to the vacuum extraction port. The vacuum device is activated to extract the gas (mainly air) inside the metal casing 1, bringing the casing to a set vacuum level (e.g., absolute pressure below 100 Pa or lower). Once the set vacuum level is reached, the sealing valve at the vacuum extraction port is closed, disconnecting the external vacuum device, and the interior of the metal casing 1 remains under vacuum. The device operates in a vacuum state for heat storage and release. The vacuum extraction port ensures that the interior of the metal casing 1 remains under vacuum, effectively suppressing convective and conductive heat transfer losses, improving heat storage efficiency, and reducing heat loss.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An electrically heated solid thermal storage unit device, characterized in that, include: Solid thermal storage particles; A metal casing, wherein the solid heat storage particles are filled inside the metal casing; An electric heating component, embedded inside the solid thermal storage particles, is used to convert electrical energy into heat energy and heat the solid thermal storage particles; An internal fin assembly is disposed on the inner wall of the metal shell and extends into the interior of the solid heat storage particles; An external fin assembly is disposed on the outer wall of the metal housing.

2. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, The solid thermal storage particles include doped and modified aluminum oxide particles, the particle size of which is 0.5 mm to 5 mm, and the doping material of which is selected from one of the following groups: Carbon powder or metal powder suitable for environments ranging from 550℃ to 1000℃, with a doping ratio of 5wt% to 15wt%; Phase change thermal storage molten salt suitable for environments ranging from 200℃ to 550℃; High-temperature heat transfer oil suitable for environments below 300°C.

3. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, The internal fin assembly includes a plurality of parallel first fins spaced apart. The thickness of the first fin is 1.5mm to 2mm, the height is 50mm to 80mm, the spacing between adjacent first fins is 30mm to 50mm, and the first fins are fixedly connected to the metal shell.

4. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, The external fin assembly includes a plurality of second fins, which are arranged spirally or in parallel along the outer wall of the metal shell. The thickness of the second fins is 1.0 mm to 1.5 mm, the height is 20 mm to 30 mm, the spacing between adjacent second fins is 10 mm to 20 mm, and the second fins are fixedly connected to the metal shell.

5. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, The materials of the internal fin assembly and the external fin assembly are configured according to the ambient temperature of use as follows: When the ambient temperature is below 400℃, it is made of carbon steel. When the ambient temperature is between 400℃ and 600℃, it is made of stainless steel. When the ambient temperature is above 600℃, the material is tungsten alloy or nickel-based alloy with an anti-oxidation coating sprayed on the surface.

6. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, The electric heating component includes a resistance wire and a high-temperature resistant wire. The resistance wire is spirally arranged inside the solid heat storage particles. One end of the high-temperature resistant wire is connected to the resistance wire, and the other end extends out of the metal shell for connecting to an external power supply device. A high-temperature resistant seal is provided at the connection between the high-temperature resistant wire and the metal shell.

7. The electrically heated solid thermal storage unit device according to claim 6, characterized in that, The resistance wire is a nickel-chromium alloy resistance wire with a diameter of 1.0mm to 1.5mm and a spiral diameter of 10mm to 15mm. The high-temperature resistant conductor is a high-temperature resistant ceramic conductor.

8. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, It also includes a temperature control sensor, which is embedded inside the solid thermal storage particles and is used to detect the temperature of the solid thermal storage particles.

9. The electrically heated solid thermal storage unit device according to claim 1, characterized in that, It also includes a vacuum pumping interface, which is disposed on the metal housing and is used to connect an external vacuum pumping device to evacuate the inside of the metal housing.

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