Power grid level energy storage system

Abstract

An outlet of a first feed pump is divided into two paths after passing through a heat exchange tube in a thermochemical reactor, one path is communicated with a steam inlet of a reversible solid oxide fuel cell, and the other path is communicated with an inlet of the heat exchange tube in the reversible solid oxide fuel cell; an outlet of a heat exchange pipe in the reversible solid oxide fuel cell is communicated with a water tank through a second water feeding pump, an oxygen outlet of the reversible solid oxide fuel cell is communicated with an oxygen storage tank, and a hydrogen outlet of the reversible solid oxide fuel cell is communicated with a hydrogen storage tank; an outlet of the first water feeding pump is communicated with a shell side opening of the thermochemical reactor, the steam storage tank is communicated with the shell side opening of the thermochemical reactor, the steam storage tank is communicated with a heat exchange pipe in the reversible solid oxide fuel cell, and the power grid is communicated with a power interface of the reversible solid oxide fuel cell. The system can realize waste heat utilization of the reversible solid oxide fuel cell, and meanwhile, the peak regulation capability of the power grid is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermochemical energy storage, and relates to an electric grid level energy storage system. BACKGROUND

[0002] The combination of reversible solid oxide fuel cells and an electric grid is an important means for realizing electric grid peak shaving. The reversible solid oxide fuel cell is a kind of high-efficiency energy conversion device, has the unique advantage of being capable of flexibly switching between a power generation mode and an electrolysis mode, and can realize bidirectional conversion of electric energy and chemical energy. However, in the actual operation process, the waste heat generated by the reversible solid oxide fuel cell is difficult to utilize.

[0003] CN111933971B discloses a hybrid energy storage and power generation system for solid oxide fuel cells. In the energy storage subsystem, the electric motor and the compressor unit are connected via a drive shaft. An interstage heat exchanger is provided between the compressors. The exhaust port of the compressor is connected to the post-stage heat exchanger, the cold storage device, and the expansion valve inlet via valves and pipes. The outlet of the expansion valve is divided into two branches: one branch is connected to the inlet of the liquid air storage tank, and the other branch is connected to the inlet of the air separation unit. The air separation unit includes two outlets: one outlet is connected to the inlet of the liquid nitrogen storage tank, and the other outlet is connected to the inlet of the liquid oxygen storage tank. The outlet of the cold water tank in the thermal storage subsystem is connected to the water-side inlet of the interstage heat exchanger and the post-stage heat exchanger of the compressor unit. The water-side outlets of the interstage heat exchanger and the post-stage heat exchanger merge and are connected to the inlet of the hot water tank. The outlet of the hot water tank is divided into two branches: one branch is connected to the water-side inlet of the oxygen-water heat exchanger, and the other branch is connected to the water-side inlet of the air-water heat exchanger. The water-side outlets of the oxygen-water heat exchanger and the air-water heat exchanger merge and are connected to the inlet of the cold water tank. The outlet of the fuel tank in the fuel cell subsystem is connected to the fuel-side inlet of the fuel preheater. The fuel-side outlet of the fuel preheater is divided into two branches: one branch connects to the fuel-side inlet of the combustion chamber, and the other branch connects to the anode inlet of the solid oxide fuel cell. The outlet of the liquid oxygen tank is connected to the oxygen-side inlet of the oxygen-water heat exchanger via a cryogenic pump and a cold storage device. The oxygen-side outlet of the oxygen-water heat exchanger is connected to the oxygen-side inlet of the oxygen preheater. The oxygen-side outlet of the oxygen preheater is divided into two branches: one branch connects to the cathode inlet of the fuel cell, and the other branch connects to the oxygen-side inlet of the combustion chamber. The anode outlet of the solid oxide fuel cell is connected to the fuel-side inlet of the combustion chamber, and the cathode outlet is connected to the oxygen-side inlet of the combustion chamber. The solid oxide fuel cell is connected to a rectifier via an external circuit. Both the electric preheating device and the fuel cell preheater are arranged within the solid structure of the solid oxide fuel cell. Both the electric preheating device and the fuel cell preheater can preheat the solid oxide fuel cell, accelerating its start-up speed. The combustion chamber outlet of the turbine-generated power system is divided into two branches: one branch connects to the turbine inlet, and the other branch connects to the fuel cell preheater inlet. The fuel cell preheater outlet is open to the atmosphere. The turbine outlet is divided into two branches: one branch connects to the atmosphere, and the other branch is connected in parallel to the exhaust-side inlet of the oxygen preheater and the exhaust-side inlet of the fuel preheater, respectively. The high-temperature exhaust-side outlet of the fuel preheater is open to the atmosphere. The high-temperature exhaust-side outlet of the oxygen preheater is open to the atmosphere. The liquid air storage tank includes two outlets, one of which is connected to the turbine via a cryogenic pump, a cold storage device, and an air-water heat exchanger. The turbine and the generator are connected via a drive shaft.

[0004] Because reversible solid oxide fuel cells operate at extremely high temperatures, typically between 600 and 1000°C, waste heat recovery systems must withstand these extreme high-temperature environments. This places stringent requirements on the high-temperature resistance and corrosion resistance of materials, resulting in high costs for suitable heat recovery materials and limiting large-scale applications. Furthermore, the complex and variable operating conditions of fuel cells, unstable power output, and uneven temporal and spatial distribution of waste heat generation make it difficult to construct a stable and efficient waste heat collection and transmission system, further increasing the difficulty of waste heat utilization. In addition, current technologies for waste heat utilization from reversible solid oxide fuel cells are still immature, lacking mature and economically feasible heat conversion and utilization schemes. This results in a large amount of waste heat being lost into the environment, causing significant energy waste and thermal pollution to the surrounding environment. This restricts the improvement of the overall energy utilization efficiency and sustainable development of reversible solid oxide fuel cells. Moreover, relying solely on reversible solid oxide fuel cells for grid peak shaving has limited peak-shaving capacity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a grid-level energy storage system that can realize the utilization of waste heat from reversible solid oxide fuel cells while improving the peak-shaving capacity of the power grid.

[0006] To achieve the above objectives, the present invention discloses a grid-level energy storage system, comprising a first feedwater pump, a steam storage tank, a thermochemical reactor, a power grid, a reversible solid oxide fuel cell, a second feedwater pump, a water tank, a hydrogen storage tank, and an oxygen storage tank. The outlet of the first feedwater pump is split into two paths after passing through the heat exchange tube in the thermochemical reactor. One path is connected to the steam inlet of the reversible solid oxide fuel cell, and the other path is connected to the inlet of the heat exchange tube in the reversible solid oxide fuel cell. The outlet of the heat exchange tube in the reversible solid oxide fuel cell is connected to the water tank via the second feedwater pump. The oxygen outlet of the reversible solid oxide fuel cell is connected to the oxygen storage tank, and the hydrogen outlet of the reversible solid oxide fuel cell is connected to the hydrogen storage tank. The outlet of the first feedwater pump is connected to the shell-side opening of the thermochemical reactor, the steam storage tank is connected to the shell-side opening of the thermochemical reactor, the steam storage tank is connected to the heat exchange tube in the reversible solid oxide fuel cell, and the power grid is connected to the power interface of the reversible solid oxide fuel cell.

[0007] A further improvement of the grid-level energy storage system described in this invention is that: Furthermore, the outlet of the first feedwater pump is connected to the heat exchange tube in the thermochemical reactor via the first valve.

[0008] Furthermore, the outlet of the first feedwater pump is connected to the shell-side opening of the thermochemical reactor via a second valve.

[0009] Furthermore, the outlet of the steam storage tank is connected to the shell-side opening of the thermochemical reactor via a third valve.

[0010] Furthermore, the outlet of the steam storage tank is connected to the heat exchange tube in the reversible solid oxide fuel cell via a fourth valve.

[0011] Furthermore, the outlet of the heat exchange tube in the thermochemical reactor is connected to the steam inlet of the reversible solid oxide fuel cell via a fifth valve.

[0012] Furthermore, the outlet of the heat exchange tube in the thermochemical reactor is connected to the heat exchange tube in the reversible solid oxide fuel cell via a sixth valve.

[0013] Furthermore, in the energy storage mode, the reversible solid oxide fuel cell operates in SOEC mode, using off-peak electricity from the grid to produce hydrogen and oxygen, which are stored in hydrogen storage tanks and oxygen storage tanks respectively. At the same time, steam in the steam storage tank enters the thermochemical reactor, where it undergoes a hydration reaction with CaO, releasing heat energy at 400~500°C. Feedwater enters the thermochemical reactor via the first feedwater pump and is heated to form high-temperature steam, providing steam preheating for the reversible solid oxide fuel cell.

[0014] Furthermore, in the power generation mode, the reversible solid oxide fuel cell switches to SOFC mode, using stored hydrogen and oxygen to generate electricity and transmit it to the grid. At the same time, the waste heat of 700-850°C generated by the reversible solid oxide fuel cell is heated by the feed water through the second feed water pump into the reversible solid oxide fuel cell to form steam, which then enters the heat exchange tube of the thermochemical reactor to heat the thermochemical reactor for heat storage. The steam after heat exchange and cooling enters the steam storage tank. Meanwhile, the steam generated during the heat storage process of the thermochemical reactor is stored in the steam storage tank.

[0015] Furthermore, in the thermal insulation and rapid response mode, heat is extracted from the steam storage tank and introduced into the reversible solid oxide fuel cell to maintain the reversible solid oxide fuel cell in a medium-high temperature standby state. After heat exchange and cooling, the condensate enters the water tank.

[0016] The present invention has the following beneficial effects: In practical operation, the grid-level energy storage system described in this invention utilizes a reversible solid oxide fuel cell in conjunction with a thermochemical reactor. In power generation mode, the reversible solid oxide fuel cell generates a large amount of waste heat at 700-850°C. Feedwater, pumped by a second feedwater pump, is heated in the reversible solid oxide fuel cell to form high-temperature steam, which then enters the heat exchange tubes of the thermochemical reactor to heat the reactor for heat storage, thus achieving waste heat recovery and utilization. Furthermore, in thermal insulation and rapid response mode, a small amount of heat is extracted from the steam storage tank and fed into the reversible solid oxide fuel cell to maintain it in a medium-to-high temperature standby state, avoiding the thermal stress and time delay caused by deep cold starts. This enables rapid response to grid dispatch commands and improves the grid's peak-shaving capacity. Attached Figure Description

[0017] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a structural diagram of the present invention.

[0018] Among them, 1 is the first water supply pump, 2 is the steam storage tank, 3 is the thermochemical reactor, 4 is the power grid, 5 is the reversible solid oxide fuel cell, 6 is the second water supply pump, 7 is the water tank, 8 is the hydrogen storage tank, and 9 is the oxygen storage tank. Detailed Implementation

[0019] 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, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0023] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0024] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0025] 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, not all, of the embodiments of the present invention. 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. Therefore, the following detailed description of the embodiments of the present 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 present invention without inventive effort are within the scope of protection of the present invention.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] Example 1 The grid-level energy storage system of this invention includes a first feedwater pump 1, a steam storage tank 2, a thermochemical reactor 3, a power grid 4, a reversible solid oxide fuel cell 5, a second feedwater pump 6, a water tank 7, a hydrogen storage tank 8, and an oxygen storage tank 9. The outlet of the first feedwater pump 1 is split into two paths after passing through the heat exchange tube in the thermochemical reactor 3. One path is connected to the steam inlet of the reversible solid oxide fuel cell 5, and the other path is connected to the inlet of the heat exchange tube in the reversible solid oxide fuel cell 5. The outlet of the heat exchange tube in the reversible solid oxide fuel cell 5 is connected to the water tank 7 via the second feedwater pump 6. The oxygen outlet of the reversible solid oxide fuel cell 5 is connected to the oxygen storage tank 9, and the hydrogen outlet of the reversible solid oxide fuel cell 5 is connected to the hydrogen storage tank 8. The outlet of the first feedwater pump 1 is connected to the shell-side opening of the thermochemical reactor 3. The steam storage tank 2 is connected to the shell-side opening of the thermochemical reactor 3. The steam storage tank 2 is connected to the heat exchange tube in the reversible solid oxide fuel cell 5. The power grid 4 is connected to the power interface of the reversible solid oxide fuel cell 5.

[0028] This invention utilizes an internal thermal cycle to use the waste heat generated in SOFC mode as the heat input required for SOEC mode. This design fundamentally reduces the additional power consumption for heating in conventional solutions.

[0029] Example 2 To improve this application, refer to Figure 1 The grid-level energy storage system of the present invention includes a first feedwater pump 1, a steam storage tank 2, a thermochemical reactor 3, a power grid 4, a reversible solid oxide fuel cell 5, a second feedwater pump 6, a water tank 7, a hydrogen storage tank 8, and an oxygen storage tank 9. The outlet of the first feedwater pump 1 is split into two paths after passing through the heat exchange tube in the thermochemical reactor 3. One path is connected to the steam inlet of the reversible solid oxide fuel cell 5, and the other path is connected to the inlet of the heat exchange tube in the reversible solid oxide fuel cell 5. The outlet of the heat exchange tube in the reversible solid oxide fuel cell 5 is connected to the water tank 7 via the second feedwater pump 6. The oxygen outlet of the reversible solid oxide fuel cell 5 is connected to the oxygen storage tank 9, and the hydrogen outlet of the reversible solid oxide fuel cell 5 is connected to the hydrogen storage tank 8.

[0030] The outlet of the first feedwater pump 1 is connected to the shell-side opening of the thermochemical reactor 3, the steam storage tank 2 is connected to the shell-side opening of the thermochemical reactor 3, the steam storage tank 2 is connected to the heat exchange tube in the reversible solid oxide fuel cell 5, and the power grid 4 is connected to the power interface of the reversible solid oxide fuel cell 5.

[0031] The outlet of the first feedwater pump 1 is connected to the heat exchange tube in the thermochemical reactor 3 via the first valve. The outlet of the first feedwater pump 1 is connected to the shell-side opening of the thermochemical reactor 3 via the second valve. The outlet of the steam storage tank 2 is connected to the shell-side opening of the thermochemical reactor 3 via the third valve. The outlet of the steam storage tank 2 is connected to the heat exchange tube in the reversible solid oxide fuel cell 5 via the fourth valve. The outlet of the heat exchange tube in the thermochemical reactor 3 is connected to the steam inlet of the reversible solid oxide fuel cell 5 via the fifth valve. The outlet of the heat exchange tube in the thermochemical reactor 3 is connected to the heat exchange tube in the reversible solid oxide fuel cell 5 via the sixth valve.

[0032] It should be noted that the thermochemical reactor 3 of the present invention utilizes the CaO / Ca(OH)2 system; the reversible solid oxide fuel cell 5 is divided into two modes: the reversible solid oxide fuel cell 5 acts as a solid oxide electrolyzer (SOEC), which uses electrical energy and thermal energy to efficiently electrolyze water vapor into hydrogen for energy storage; the reversible solid oxide fuel cell 5 acts as a solid oxide fuel cell (SOFC), which uses the stored hydrogen to generate electricity.

[0033] The working process of this invention is as follows: Energy Storage Mode (Off-Peak Electricity Period): The reversible solid oxide fuel cell 5 operates in SOEC mode, utilizing off-peak electricity from grid 4 to produce hydrogen and oxygen, which are stored in hydrogen storage tank 8 and oxygen storage tank 9, respectively. Simultaneously, the thermochemical reactor 3 has completed heat storage in the previous power generation cycle. Steam from steam storage tank 2 enters the thermochemical reactor 3, where it undergoes a hydration reaction with CaO, releasing heat energy at 400-500°C. Feedwater, via the first feedwater pump 1, enters the thermochemical reactor 3 and is heated to form high-temperature steam, providing efficient steam preheating for the reversible solid oxide fuel cell 5, thereby minimizing the power consumption of the electrolysis process.

[0034] Power generation mode (peak electricity period): The reversible solid oxide fuel cell 5 switches to SOFC mode, using stored hydrogen and oxygen to generate electricity and supply high-priced electricity to the grid 4. At the same time, the reversible solid oxide fuel cell 5 generates a large amount of waste heat at 700-850°C. Feed water enters the reversible solid oxide fuel cell 5 via the second feed water pump 6 and is heated to form high-temperature steam. Then, it enters the heat exchange tubes of the thermochemical reactor 3 to heat the thermochemical reactor 3 for heat storage, preparing for the next energy storage mode. The steam after heat exchange and cooling enters the steam storage tank 2. At the same time, the steam generated during the heat storage process in the thermochemical reactor 3 is also stored in the steam storage tank 2.

[0035] Thermal insulation and rapid response mode: During system standby, a small amount of heat is extracted from the steam storage tank 2 and introduced into the reversible solid oxide fuel cell 5 to maintain the reversible solid oxide fuel cell 5 in a medium-high temperature standby state, avoiding thermal stress and time delay caused by deep cold start, thereby realizing rapid response to the dispatch command of the power grid 4. After heat exchange and cooling, the condensate enters the water tank 7. This invention has the following characteristics: The system exhibits high stability and long lifespan: The thermochemical reactor 3 acts as a thermal inertia buffer, smoothing out the drastic temperature fluctuations caused by SOC mode switching. By maintaining SOC operation within a stable high-temperature range, the risk of material aging and performance degradation due to thermal stress cycling is significantly reduced, extending the lifespan of core components.

[0036] Precise parameter matching and synergy: The coupling design of this invention is based on the perfect matching of the operating temperature ranges of each unit. The waste heat temperature of the reversible solid oxide fuel cell 5 (>700°C) is much higher than the heat storage requirement temperature of the thermochemical reactor 3 (500-600°C), ensuring efficient heat transfer driving force. The exothermic temperature of the thermochemical reactor 3 (~400°C) is very suitable as a preheating heat source for the feed steam of the thermochemical reactor 3, realizing the cascade utilization of energy and minimizing energy loss.

[0037] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0038] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0039] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A grid-scale energy storage system, characterized in that, It includes a first water pump (1), a steam storage tank (2), a thermochemical reactor (3), a power grid (4), a reversible solid oxide fuel cell (5), a second water pump (6), a water tank (7), a hydrogen storage tank (8), and an oxygen storage tank (9); The outlet of the first feed water pump (1) is divided into two paths after passing through the heat exchange tube in the thermochemical reactor (3). One path is connected to the steam inlet of the reversible solid oxide fuel cell (5), and the other path is connected to the inlet of the heat exchange tube in the reversible solid oxide fuel cell (5). The outlet of the heat exchange tube in the reversible solid oxide fuel cell (5) is connected to the water tank (7) via the second feed water pump (6). The oxygen outlet of the reversible solid oxide fuel cell (5) is connected to the oxygen storage tank (9), and the hydrogen outlet of the reversible solid oxide fuel cell (5) is connected to the hydrogen storage tank (8). The outlet of the first water pump (1) is connected to the shell-side opening of the thermochemical reactor (3), the steam tank (2) is connected to the shell-side opening of the thermochemical reactor (3), the steam tank (2) is connected to the heat exchange tube in the reversible solid oxide fuel cell (5), and the power grid (4) is connected to the power interface of the reversible solid oxide fuel cell (5).

2. The grid-level energy storage system according to claim 1, characterized in that, The outlet of the first water pump (1) is connected to the heat exchange tube in the thermochemical reactor (3) via the first valve.

3. The grid-level energy storage system according to claim 1, characterized in that, The outlet of the first water pump (1) is connected to the shell-side opening of the thermochemical reactor (3) via the second valve.

4. The grid-level energy storage system according to claim 1, characterized in that, The outlet of the steam storage tank (2) is connected to the shell-side opening of the thermochemical reactor (3) via a third valve.

5. The grid-scale energy storage system according to claim 1, characterized in that, The outlet of the steam storage tank (2) is connected to the heat exchange tube in the reversible solid oxide fuel cell (5) via the fourth valve.

6. The grid-level energy storage system according to claim 1, characterized in that, The outlet of the heat exchange tube in the thermochemical reactor (3) is connected to the steam inlet of the reversible solid oxide fuel cell (5) via the fifth valve.

7. The grid-level energy storage system according to claim 1, characterized in that, The outlet of the heat exchange tube in the thermochemical reactor (3) is connected to the heat exchange tube in the reversible solid oxide fuel cell (5) via the sixth valve.

8. The grid-level energy storage system according to claim 1, characterized in that, In the energy storage mode, the reversible solid oxide fuel cell (5) operates in SOEC mode, using off-peak electricity from the power grid (4) to produce hydrogen and oxygen, which are stored in hydrogen storage tank (8) and oxygen storage tank (9) respectively. At the same time, the steam in the steam storage tank (2) enters the thermochemical reactor (3) and reacts with CaO to release heat energy of 400~500°C. The feed water enters the thermochemical reactor (3) through the first feed water pump (1) and is heated to form high-temperature steam, providing steam preheating for the reversible solid oxide fuel cell (5).

9. The grid-level energy storage system according to claim 1, characterized in that, In the power generation mode, the reversible solid oxide fuel cell (5) switches to SOFC mode and generates electricity using stored hydrogen and oxygen, which is then transmitted to the power grid (4). At the same time, the waste heat generated by the reversible solid oxide fuel cell (5) at 700-850°C is heated by the feed water through the second feed water pump (6) into the reversible solid oxide fuel cell (5) to form steam, which then enters the heat exchange tube of the thermochemical reactor (3) to heat the thermochemical reactor (3) for heat storage. The steam after heat exchange and cooling enters the steam storage tank (2), and the steam generated during the heat storage process of the thermochemical reactor (3) is stored in the steam storage tank (2).

10. The grid-scale energy storage system according to claim 1, characterized in that, In the thermal insulation and rapid response mode, heat is extracted from the steam storage tank (2) and enters the reversible solid oxide fuel cell (5) to maintain the reversible solid oxide fuel cell (5) in a medium-high temperature standby state. After heat exchange and cooling, the condensate enters the water tank (7).

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