Short-time energy storage system of fused salt energy storage coupled fuel cell

Abstract

The invention provides a short-time energy storage system of a fused salt energy storage coupled fuel cell. The short-time energy storage system comprises a solid oxide electrolytic tank, a hydrogen storage tank, an oxygen storage tank, a solid oxide fuel cell, a high-temperature fused salt storage tank and a low-temperature fused salt storage tank, the solid oxide electrolytic tank is used for carrying out water electrolysis reaction to generate hydrogen and oxygen; the hydrogen storage tank is used for storing hydrogen generated by electrolysis; the oxygen storage tank is used for storing oxygen generated by electrolysis; the solid oxide fuel cell is respectively communicated with the hydrogen storage tank and the oxygen storage tank and is used for carrying out chemical reaction by utilizing hydrogen and oxygen to release energy; the high-temperature fused salt storage tank is communicated to the low-temperature fused salt storage tank through the solid oxide electrolytic cell and the solid oxide fuel cell respectively, so that the high-temperature fused salt enters the low-temperature fused salt storage tank after the solid oxide electrolytic cell and the solid oxide fuel cell release heat to provide heat required by reaction. According to the system, efficient, stable and economical short-time energy storage can be achieved, and therefore the defects of an existing fused salt energy storage technology in the aspect of short-time energy storage are overcome.

Description

Technical Field

[0001] This application relates to the field of energy storage and power generation technology, and more specifically, to a short-time energy storage system coupled with a molten salt energy storage fuel cell. Background Technology

[0002] With the large-scale grid connection of renewable energy sources (such as wind power and photovoltaics), their inherent intermittency and volatility pose a severe challenge to the stable operation of the power grid. Energy storage technology, as a key means of balancing electricity supply and demand, directly determines the large-scale absorption capacity of renewable energy through its performance and cost. Currently, the main energy storage technology used is molten salt energy storage (TES), which features large capacity, long lifespan, high security, and economy, giving it advantages in long-term thermal energy storage. However, the thermal inertia of molten salt energy storage technology results in slow system startup and power regulation response (on the order of minutes), making it difficult to cope with the rapid power fluctuations in the grid, ranging from seconds to minutes. Summary of the Invention

[0003] This application provides at least one short-time energy storage system coupled to a fuel cell using molten salt energy storage. This system can achieve efficient, stable, and economical short-time energy storage, thereby overcoming the shortcomings of existing molten salt energy storage technology in short-time energy storage.

[0004] This application provides a short-term energy storage system for molten salt energy storage coupled with a fuel cell. The system includes: a solid oxide electrolyzer, a hydrogen storage tank, an oxygen storage tank, a solid oxide fuel cell, a high-temperature molten salt storage tank, and a low-temperature molten salt storage tank.

[0005] The solid oxide electrolyzer is used to electrolyze water using new energy power generation and redundant power from generator sets to produce hydrogen and oxygen.

[0006] The inlet of the hydrogen storage tank is connected to the hydrogen outlet of the solid oxide electrolyzer, and is used to store the hydrogen produced by electrolysis.

[0007] The inlet of the oxygen storage tank is connected to the oxygen outlet of the solid oxide electrolytic cell, and is used to store the oxygen produced by electrolysis.

[0008] The hydrogen inlet and oxygen inlet of the solid oxide fuel cell are connected to the outlet of the hydrogen storage tank and the outlet of the oxygen storage tank, respectively, for releasing energy through a chemical reaction using hydrogen and oxygen.

[0009] The first and second molten salt outlets of the high-temperature molten salt storage tank are respectively connected to the low-temperature molten salt storage tank via the solid oxide electrolysis cell and the solid oxide fuel cell, so that the high-temperature molten salt enters the low-temperature molten salt storage tank after the solid oxide electrolysis cell and the solid oxide fuel cell release heat to provide the heat required for the reaction.

[0010] In one optional embodiment, both the solid oxide electrolyzer and the solid oxide fuel cell are provided with molten salt heat exchange pipes, which are used for high-temperature molten salt to pass through and release heat.

[0011] In one alternative embodiment, the system further includes a generator connected to the solid oxide fuel cell for converting energy released from the chemical reaction into electrical energy.

[0012] In one alternative embodiment, the generator's drain outlet is connected to the solid oxide fuel cell's water inlet.

[0013] In one optional embodiment, the molten salt outlet of the low-temperature molten salt storage tank is connected to the molten salt inlet of the high-temperature molten salt storage tank;

[0014] The system further includes a photothermal cluster connected to the cryogenic molten salt storage tank, used to heat the cryogenic molten salt in the cryogenic molten salt storage tank using photothermal energy.

[0015] In an optional embodiment, the system further includes an electric heater, the inlet and outlet of which are connected to the molten salt outlet of the low-temperature molten salt storage tank and the molten salt inlet of the high-temperature molten salt storage tank, respectively, for heating the molten salt output from the low-temperature molten salt storage tank using renewable energy power generation and redundant power from the generator set when the solar thermal cluster's heating is insufficient.

[0016] In one alternative embodiment, the power of the electric heater is adjustable to dynamically adjust the heating power according to the molten salt temperature requirement.

[0017] In one optional implementation, the system further includes a control module, which is used to switch between electrolysis and energy release modes in real time according to the power grid frequency signal.

[0018] The above-mentioned technical solution of this application has the following beneficial technical effects:

[0019] The molten salt energy storage coupled fuel cell short-time energy storage system of this application embodiment improves the system's energy storage and release efficiency by coupling molten salt energy storage technology with hydrogen fuel cells, enabling the system to achieve efficient, stable and economical short-time energy storage, thereby making up for the shortcomings of existing molten salt energy storage technology in short-time energy storage.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. These drawings are incorporated in and constitute a part of this specification. They illustrate embodiments conforming to this application and, together with the specification, serve to explain the technical solutions of this application. It should be understood that the following drawings only show some embodiments of this application and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A schematic diagram of a short-time energy storage system coupled to a fuel cell using molten salt energy storage, as provided in an embodiment of this application, is shown.

[0023] In the picture:

[0024] 1. Solid oxide electrolyzer; 2. Hydrogen storage tank; 3. Oxygen storage tank; 4. Solid oxide fuel cell; 5. High-temperature molten salt storage tank; 6. Low-temperature molten salt storage tank; 7. Generator; 8. Photothermal cluster; 9. Electric heater. Detailed Implementation

[0025] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0026] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0028] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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 this application.

[0029] In the description of this application, it should be noted that, unless otherwise expressly 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 an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] With the large-scale grid connection of renewable energy sources (such as wind power and photovoltaics), their inherent intermittency and volatility pose a severe challenge to the stable operation of the power grid. Energy storage technology, as a key means of balancing electricity supply and demand, directly determines the large-scale absorption capacity of renewable energy through its performance and cost. Currently, the main energy storage technology used is molten salt energy storage (TES), which features large capacity, long lifespan, high security, and economy, giving it advantages in long-term thermal energy storage. However, the thermal inertia of molten salt energy storage technology results in slow system startup and power regulation response (on the order of minutes), making it difficult to cope with the rapid power fluctuations in the grid, ranging from seconds to minutes.

[0031] Therefore, this application provides a short-time energy storage system coupled with a molten salt energy storage fuel cell, which can achieve efficient, stable and economical short-time energy storage, thereby making up for the shortcomings of existing molten salt energy storage technology in short-time energy storage.

[0032] like Figure 1As shown, the short-term energy storage system of molten salt energy storage coupled to a fuel cell provided in this application embodiment includes a solid oxide electrolyzer 1, a hydrogen storage tank 2, an oxygen storage tank 3, a solid oxide fuel cell 4, a high-temperature molten salt storage tank 5, and a low-temperature molten salt storage tank 6. The solid oxide electrolyzer 1 is used to electrolyze water using the redundant power from new energy power generation and generator 7 to generate hydrogen and oxygen. The inlet of the hydrogen storage tank 2 is connected to the hydrogen outlet of the solid oxide electrolyzer 1 and is used to store the hydrogen generated by electrolysis. The inlet of the oxygen storage tank 3 is connected to the oxygen outlet of the solid oxide electrolyzer 1 and is used to store the oxygen generated by electrolysis. The hydrogen inlet and oxygen inlet of the solid oxide fuel cell 4 are connected to the outlets of the hydrogen storage tank 2 and oxygen storage tank 3, respectively, for using hydrogen and oxygen to perform a chemical reaction to release energy. The first and second molten salt outlets of the high-temperature molten salt storage tank 5 are connected to the low-temperature molten salt storage tank 6 via the solid oxide electrolysis cell 1 and the solid oxide fuel cell 4, respectively, so that the high-temperature molten salt enters the low-temperature molten salt storage tank 6 after the high-temperature molten salt releases heat in the solid oxide electrolysis cell 1 and the solid oxide fuel cell 4 to provide the heat required for the reaction.

[0033] This short-term energy storage system coupled with a molten salt fuel cell utilizes a solid oxide electrolyzer 1, a hydrogen storage tank 2, and an oxygen storage tank 3 for energy storage, and a solid oxide fuel cell 4 for energy release. The molten salt energy storage system provides the heat required for the reactions in the solid oxide electrolyzer 1 and the solid oxide fuel cell 4. The solid oxide electrolyzer 1 and the solid oxide fuel cell 4 offer advantages such as high energy conversion efficiency and fast response rate during energy release. Their combined operation improves the system's energy storage and release efficiency, enabling short-term energy storage. The molten salt energy storage system (high-temperature molten salt tank 5 and low-temperature molten salt tank 6) is used only for heating and does not generate electricity, thus contributing to the system's simplicity and energy conversion efficiency.

[0034] It should be noted that the H2 and O2 produced by the solid oxide electrolytic cell 1 can not only be used for power generation, but also be processed as chemical products.

[0035] In some embodiments, both the solid oxide electrolyzer 1 and the solid oxide fuel cell 4 are equipped with molten salt heat exchange pipes, which are used for the passage and heat release of high-temperature molten salt. Specifically, the high-temperature molten salt output from the high-temperature molten salt storage tank 5 actually enters the low-temperature molten salt storage tank 6 through the molten salt heat exchange pipes in the solid oxide electrolyzer 1 and the solid oxide fuel cell 4. Furthermore, the high-temperature molten salt releases heat when passing through the molten salt heat exchange pipes, providing the necessary heat for the water electrolysis reaction and the chemical reaction.

[0036] In some embodiments, the short-term energy storage system of the molten salt energy storage coupled to the fuel cell further includes a first valve and a second valve. The first valve is located at the first molten salt outlet of the high-temperature molten salt storage tank 5, and the second valve is located at the second molten salt outlet of the high-temperature molten salt storage tank 5. This configuration facilitates the control of the energy storage and release processes. Specifically, during energy storage, the first valve is open and the second valve is closed; during energy release, the first valve is closed and the second valve is open.

[0037] In some embodiments, the short-term energy storage system of the molten salt energy storage coupled fuel cell further includes a generator 7 connected to the solid oxide fuel cell 4, used to convert the energy released by the chemical reaction into electrical energy. That is, the system generates electricity during the energy release process. In this embodiment, the generator 7 uses the steam generated during the chemical reaction of the solid oxide fuel cell 4 to generate electricity. Specifically, the inlet of the generator 7 is connected to the outlet of the solid oxide fuel cell 4, and the high-temperature steam generated by the chemical reaction enters the generator 7, where it performs work to drive the generator 7 to generate electricity.

[0038] In some embodiments, the drain outlet of the generator 7 is connected to the water inlet of the solid oxide fuel cell 4. That is, after the high-temperature steam performs work, it condenses into water, and the water returns to the solid oxide fuel cell 4 through the drain outlet of the generator 7 to continue the chemical reaction. This configuration enables water recycling and reduces system water consumption.

[0039] In some embodiments, the molten salt outlet of the cryogenic molten salt storage tank 6 is connected to the molten salt inlet of the high-temperature molten salt storage tank 5. This configuration enables the recycling of molten salt. Of course, in order to ensure that the molten salt in the cryogenic molten salt storage tank 6 meets the temperature requirements (e.g., 500–800°C), the cryogenic molten salt needs to be heated to become high-temperature molten salt before entering the high-temperature molten salt storage tank 5.

[0040] In some embodiments, the short-term energy storage system of molten salt energy storage coupled to a fuel cell further includes a solar thermal cluster 8, which is connected to a cryogenic molten salt storage tank 6 for utilizing solar thermal energy to heat the cryogenic molten salt in the cryogenic molten salt storage tank 6. In this embodiment, the solar thermal cluster 8 includes a solar collector and a molten salt heater. The solar collector is used to collect solar energy, and the molten salt heater and the cryogenic molten salt storage tank 6 are cyclically connected. When the cryogenic molten salt passes through the molten salt heater, the cryogenic molten salt absorbs solar energy and its temperature rises.

[0041] In some embodiments, the short-term energy storage system of molten salt energy storage coupled to a fuel cell further includes an electric heater 9. The inlet and outlet of the electric heater 9 are connected to the molten salt outlet of the cryogenic molten salt storage tank 6 and the molten salt inlet of the high-temperature molten salt storage tank 5, respectively. This is used to heat the molten salt output from the cryogenic molten salt storage tank 6 using renewable energy generation and the redundant power from the generator 7 when the solar thermal cluster 8 provides insufficient heat. This configuration ensures the temperature of the high-temperature molten salt even during nighttime or rainy weather when the solar thermal cluster 8 provides insufficient heat. Specifically, the electric heater 9 is connected in series in the connecting pipe between the molten salt outlet of the cryogenic molten salt storage tank 6 and the molten salt inlet of the high-temperature molten salt storage tank 5. The cryogenic molten salt output from the cryogenic molten salt storage tank 6 is heated by the electric heater 9 before entering the high-temperature molten salt storage tank 5. Furthermore, since the electric heater 9 only uses renewable energy generation and the redundant power from the generator 7 for heating when the solar thermal cluster 8 provides insufficient heat, this helps improve the system's energy storage efficiency.

[0042] In some embodiments, the power of the electric heater 9 is adjustable to dynamically adjust the heating power according to the molten salt temperature requirement. This configuration ensures the molten salt temperature in the high-temperature molten salt storage tank 5. Specifically, when the heat provided by the solar thermal cluster 8 is insufficient to bring the molten salt to the set temperature range, and the temperature is either too high or too low, the electric heater 9 can appropriately increase its heating power when the molten salt temperature is low to bring the molten salt to the set temperature range, or appropriately decrease its heating power when the molten salt temperature is high to avoid wasting electrical energy.

[0043] In some embodiments, the short-term energy storage system of molten salt energy storage coupled with a fuel cell further includes a control module, which is used to switch the electrolysis and energy release modes in real time according to the grid frequency signal. Specifically, the control module is communicatively connected (or electrically connected) to the solid oxide electrolyzer 1, hydrogen storage tank 2, oxygen storage tank 3, solid oxide fuel cell 4, high-temperature molten salt storage tank 5, and low-temperature molten salt storage tank 6, respectively. When the generator set 7 is operating at reduced load, the control module controls each device to cooperate in energy storage; when the generator set 7 is operating at increased load, the control module controls each device to cooperate in energy release and power generation.

[0044] The molten salt energy storage coupled fuel cell short-time energy storage system of this application embodiment improves the system's energy storage and release efficiency by coupling molten salt energy storage technology with hydrogen fuel cells, enabling the system to achieve efficient, stable and economical short-time energy storage, thereby making up for the shortcomings of existing molten salt energy storage technology in short-time energy storage.

[0045] One or more embodiments in this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this specification should be included within the protection scope of this application.

[0046] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A short-term energy storage system coupled with a molten salt energy storage fuel cell, characterized in that, The system includes: a solid oxide electrolyzer, a hydrogen storage tank, an oxygen storage tank, a solid oxide fuel cell, a high-temperature molten salt storage tank, and a low-temperature molten salt storage tank; The solid oxide electrolyzer is used to electrolyze water using new energy power generation and redundant power from generator sets to produce hydrogen and oxygen. The inlet of the hydrogen storage tank is connected to the hydrogen outlet of the solid oxide electrolyzer, and is used to store the hydrogen produced by electrolysis. The inlet of the oxygen storage tank is connected to the oxygen outlet of the solid oxide electrolytic cell, and is used to store the oxygen produced by electrolysis. The hydrogen inlet and oxygen inlet of the solid oxide fuel cell are connected to the outlet of the hydrogen storage tank and the outlet of the oxygen storage tank, respectively, for releasing energy through a chemical reaction using hydrogen and oxygen. The first and second molten salt outlets of the high-temperature molten salt storage tank are respectively connected to the low-temperature molten salt storage tank via the solid oxide electrolysis cell and the solid oxide fuel cell, so that the high-temperature molten salt enters the low-temperature molten salt storage tank after the solid oxide electrolysis cell and the solid oxide fuel cell release heat to provide the heat required for the reaction.

2. The short-time energy storage system of molten salt energy storage coupled with a fuel cell according to claim 1, characterized in that, Both the solid oxide electrolyzer and the solid oxide fuel cell are equipped with molten salt heat exchange pipes, which are used for the passage of high-temperature molten salt and the release of heat.

3. The short-time energy storage system of molten salt energy storage coupled with a fuel cell according to claim 1, characterized in that, The system further includes a generator connected to the solid oxide fuel cell for converting the energy released by the chemical reaction into electrical energy.

4. The short-time energy storage system of molten salt energy storage coupled with a fuel cell according to claim 3, characterized in that, The generator's drain outlet is connected to the solid oxide fuel cell's water inlet.

5. The short-time energy storage system of molten salt energy storage coupled with a fuel cell according to claim 1, characterized in that, The molten salt outlet of the low-temperature molten salt storage tank is connected to the molten salt inlet of the high-temperature molten salt storage tank; The system further includes a photothermal cluster connected to the cryogenic molten salt storage tank, used to heat the cryogenic molten salt in the cryogenic molten salt storage tank using photothermal energy.

6. The short-time energy storage system of molten salt energy storage coupled to a fuel cell according to claim 5, characterized in that, The system also includes an electric heater, the inlet and outlet of which are connected to the molten salt outlet of the low-temperature molten salt storage tank and the molten salt inlet of the high-temperature molten salt storage tank, respectively, for heating the molten salt output from the low-temperature molten salt storage tank using renewable energy power generation and redundant power from the generator set when the solar thermal cluster's heating is insufficient.

7. The short-time energy storage system of molten salt energy storage coupled with a fuel cell according to claim 6, characterized in that, The power of the electric heater is adjustable, allowing for dynamic adjustment of the heating power according to the molten salt temperature requirements.

8. The short-time energy storage system of molten salt energy storage coupled to a fuel cell according to claim 1, characterized in that, The system also includes a control module, which is used to switch between electrolysis and energy release modes in real time according to the power grid frequency signal.

Images