A heat pump power storage system based on alkali metal thermoelectric conversion

Abstract

The present invention discloses a heat pump power storage system based on alkali metal thermoelectric conversion, including a heat pump heating energy storage circuit, a heat release circulation circuit and an alkali metal thermoelectric conversion circuit; the alkali metal thermoelectric conversion circuit includes a high-temperature heat exchanger, an alkali metal thermoelectric converter, a second low-temperature heat exchanger and an electromagnetic pump, the outlet of the high-temperature heat exchanger on the heat absorption side is connected to the inlet of the alkali metal thermoelectric converter through a pipeline, the outlet of the alkali metal thermoelectric converter is connected to the inlet of the heat release side of the second low-temperature heat exchanger through a pipeline, and the outlet of the second low-temperature heat exchanger on the heat release side is connected to the inlet of the high-temperature heat exchanger on the heat absorption side through a pipeline; the electromagnetic pump is installed on a pipeline with alkali metal single substance, and is arranged between the second low-temperature heat exchanger and the high-temperature heat exchanger. The present invention realizes the effective storage and reuse of energy such as off-peak electricity of power stations and renewable energy generation by combining heat pump heating technology with alkali metal thermoelectric conversion technology.

Description

Technical Field

[0001] The present invention relates to the field of energy storage, and in particular to a heat pump power storage system based on alkali metal thermoelectric conversion. Background Art

[0002] In recent years, the application of renewable energy generation technologies such as photovoltaic power generation and wind power generation has become increasingly popular, but this type of energy is intermittent and unstable. The existing power grid has limited absorption capacity, and there is a significant peak-to-valley difference in the current power grid. The peak period of electricity consumption will increase the burden on the power grid, and the low period of electricity consumption will reduce the efficiency and economy of the power grid. In this context, the development of energy storage technology has become the key to solving such problems. There is an urgent need for peak load regulation of the power grid, improving the reliability of the power grid and improving the quality of power. Energy storage is the process of storing energy through a certain medium or device and releasing it when needed. It can significantly improve the absorption level of renewable energy such as wind and light, support the development of distributed power and microgrids, promote open sharing and flexible trading of energy production and consumption, and realize multi-energy synergy. It is the core foundation for building an energy Internet, promoting power system reform and promoting the development of new energy formats.

[0003] The development of energy storage technology is an urgent need for the large-scale utilization of renewable energy. It is also an effective way to improve the efficiency, safety and economy of conventional power systems, as well as a key technology for smart grids and distributed energy systems. According to different forms of energy storage, energy storage technology is divided into pumped storage, compressed air storage, battery storage, superconducting storage, flywheel storage and supercapacitors. Among them, physical methods of energy storage represented by pumped storage, heat storage and compressed air storage are suitable for large-scale commercial applications due to their low cost and large energy storage capacity. Water storage has the advantages of large capacity, high efficiency, mature technology and long energy storage cycle. It is currently the most widely used power storage system. However, due to the long construction period of pumped storage and the need to build two libraries and dams at the same time, there are difficulties in site selection and huge initial investment, which causes ecological and immigration problems.

[0004] Heat pump power storage technology is an energy storage technology developed based on power cycle and thermal energy storage technology. Compared with other large-scale energy storage technologies, heat pump power storage systems have the advantages of not being restricted by geographical conditions, low cost, high energy storage density and high system efficiency. However, the current heat pump power storage system usually requires the configuration of large-scale heat storage and cold storage devices and traditional generator sets to meet energy storage requirements, and there is still a need for great improvement in terms of energy storage cost and energy storage timeliness. Summary of the invention

[0005] Purpose of the invention: In view of the above problems, the purpose of the present invention is to provide a heat pump power storage system based on alkali metal thermoelectric conversion. By combining heat pump heating technology with alkali metal thermoelectric conversion technology, it realizes the effective storage and reuse of power plant off-peak electricity, renewable energy generation and other energy.

[0006] Technical solution: A heat pump power storage system based on alkali metal thermoelectric conversion of the present invention comprises a heat pump heating energy storage circuit, a heat release circulation circuit and an alkali metal thermoelectric conversion circuit. The heat pump heating energy storage circuit stores high-temperature thermal energy and transfers the high-temperature thermal energy to the alkali metal thermoelectric conversion circuit via the heat release circulation circuit. The alkali metal thermoelectric conversion circuit converts the high-temperature thermal energy into electrical energy by controlling the movement of the alkali metal element.

[0007] The alkali metal thermoelectric conversion circuit includes a high-temperature heat exchanger, an alkali metal thermoelectric converter, a second low-temperature heat exchanger and an electromagnetic pump. The outlet of the high-temperature heat exchanger on the heat absorption side is connected to the inlet of the alkali metal thermoelectric converter through a pipeline, the outlet of the alkali metal thermoelectric converter is connected to the inlet of the second low-temperature heat exchanger on the heat release side through a pipeline, and the outlet of the second low-temperature heat exchanger on the heat release side is connected to the inlet of the high-temperature heat exchanger on the heat absorption side through a pipeline; the electromagnetic pump is installed on the pipeline with alkali metal single substance, and the electromagnetic pump is arranged between the second low-temperature heat exchanger and the high-temperature heat exchanger.

[0008] Furthermore, the alkali metal thermoelectric converter includes an alkali metal channel and a Base diaphragm arranged in the middle of the alkali metal channel, and both sides of the Base diaphragm are connected to an external load through a wire loop.

[0009] Furthermore, the Base diaphragm is composed of a solid electrolyte containing aluminum oxide and a porous electrode.

[0010] Furthermore, the heat pump heating energy storage circuit includes a driving unit, a compressor unit, a high-temperature heat accumulator, an expansion unit and a first low-temperature heat exchanger. The driving unit is connected to the compressor unit and the expansion unit through a common transmission shaft. The outlet of the compressor unit is connected to the inlet of the high-temperature heat accumulator through a pipeline, the outlet of the high-temperature heat accumulator is connected to the inlet of the expansion unit through a pipeline, the outlet of the expansion unit is connected to the inlet of the heat release side of the first low-temperature heat exchanger through a pipeline, and the outlet of the heat release side of the first low-temperature heat exchanger is connected to the inlet of the compressor unit through a pipeline.

[0011] Furthermore, the heat release circulation loop includes a high-temperature heat accumulator, a circulation pump and a high-temperature heat exchanger. The outlet of the high-temperature heat accumulator is connected to the inlet of the heat release side of the high-temperature heat exchanger through a pipeline. The circulation pump is arranged on the pipeline behind the outlet of the high-temperature heat accumulator, and the outlet of the heat release side of the high-temperature heat exchanger is connected to the inlet of the high-temperature heat accumulator through a pipeline.

[0012] Furthermore, the two ends of the high-temperature heat accumulator are respectively connected to the first three-way valve and the second three-way valve, the other two ends of the first three-way valve are respectively connected to the inlet of the circulation pump and the outlet of the compressor unit, and the other two ends of the second three-way valve are respectively connected to the inlet of the expansion unit and the outlet of the heat release side of the high-temperature heat exchanger. When storing electricity, the three-way valve controls the heat pump heating energy storage circuit to be opened and the heat release circulation circuit to be closed; when generating electricity, the three-way valve controls the heat release circulation circuit to be opened and the heat pump heating energy storage circuit to be closed.

[0013] Furthermore, the working fluid used in the alkali metal thermoelectric converter is sodium or potassium, or one of the following alloys, or a mixture of at least two of sodium-potassium alloy, Na-Pb alloy, and Na-Sn alloy.

[0014] Furthermore, the operating temperature of the alkali metal thermoelectric converter is 600-1100°C, and the working medium temperature in the low-temperature heat exchanger is 100-500°C.

[0015] Furthermore, the alkali metal thermoelectric conversion circuit also includes a distillation separation chamber, and the two sides of the Base diaphragm are sodium metal element and sodium molten alloy respectively. The alkali metal thermoelectric converter is connected to the inlet of the distillation separation chamber through a pipeline, and the outlet of the distillation separation chamber is connected to the inlet of the alkali metal thermoelectric converter through a pipeline. The electromagnetic pump is arranged on the pipeline after the outlet of the distillation separation chamber, and the distillation separation chamber and the electromagnetic pump are heated in the first heating space; the outlet of the distillation separation chamber is connected to the inlet of the heat release side of the second low-temperature heat exchanger through a pipeline, and the outlet of the heat release side of the second low-temperature heat exchanger is connected to the alkali metal thermoelectric converter through a pipeline, and a second electromagnetic pump is arranged on the pipeline after the outlet of the heat release side of the second low-temperature heat exchanger.

[0016] Furthermore, the heat absorbing side of the second low-temperature heat exchanger is connected to a sodium-sulfur battery pack, the sodium-sulfur battery pack is placed in a second heating space, and heat is transferred between the second heating space and the second low-temperature heat exchanger.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0018] 1. The present invention includes a heat pump heating energy storage circuit and an alkali metal thermoelectric conversion circuit. When storing electricity, the heat pump heating circulation circuit is electrically driven to produce high-temperature heat energy and store it in a high-temperature heat accumulator; when generating electricity, the alkali metal thermoelectric conversion circuit directly converts high-temperature heat energy into electrical energy by controlling the movement of alkali metal elements. The present invention combines heat pump heating technology with alkali metal thermoelectric conversion technology to achieve effective storage and reuse of energy such as off-peak electricity in power stations and renewable energy generation;

[0019] 2. The heat pump energy storage system based on alkali metal thermoelectric conversion of the present invention has the advantages of compact structure, small footprint, long energy storage time, high energy storage density, and independent controllable energy storage and power generation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the heat pump power storage system in Example 1;

[0021] Figure 2 It is a schematic diagram of the structure of an alkali metal thermoelectric converter;

[0022] Figure 3 This is a schematic diagram of the structure of the heat pump power storage system in Example 2;

[0023] Figure 4 This is a schematic diagram of the structure of the heat pump power storage system in Example 3. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0025] Example 1

[0026] like Figure 1 The heat pump power storage system based on alkali metal thermoelectric conversion described in this embodiment includes a heat pump heating energy storage circuit for storing high-temperature thermal energy; a heat release circulation circuit for transferring high-temperature thermal energy to the alkali metal thermoelectric conversion circuit; and an alkali metal thermoelectric conversion circuit for converting high-temperature thermal energy into electrical energy by controlling the movement of alkali metal elements.

[0027] The heat pump heating energy storage circuit includes a drive unit 1, a compressor unit 2, a high-temperature heat accumulator 4, an expansion unit 3, and a first low-temperature heat exchanger 5. The drive unit 1 is connected to the compressor unit 2 and the expansion unit 3 through a common transmission shaft. The outlet of the compressor unit 2 is connected to the inlet of the high-temperature heat accumulator 4 through a pipeline, the outlet of the high-temperature heat accumulator 4 is connected to the inlet of the expansion unit 3 through a pipeline, the outlet of the expansion unit 3 is connected to the inlet of the heat release side of the first low-temperature heat exchanger 5 through a pipeline, and the outlet of the heat release side 5 of the first low-temperature heat exchanger is connected to the inlet of the compressor unit 2 through a pipeline.

[0028] The heat pump heating energy storage loop pipeline is filled with circulating gas as a working medium. The circulating gas working medium is one of argon, helium, hydrogen, nitrogen, oxygen or air, or a mixture of at least two of them.

[0029] The driving unit 1 includes one or more of conventional power station off-peak electricity, nuclear power, wind power, solar power, hydropower or tidal power as power sources, and the high-temperature thermal energy prepared by the heat pump heating energy storage circuit is stored in the high-temperature heat accumulator 4. In order to achieve high efficiency of the heating circuit, the high-temperature heat accumulator 4 adopts a fixed bed sensible heat storage technology with a high heat exchange area. A very small terminal temperature difference can be obtained by the movement of the inclined temperature layer in the fixed bed, so that the sensible heat storage has a very high heat storage density. The high-temperature heat accumulator 4 adopts a packed bed type energy storage device, which is cylindrical, spherical or rectangular as a whole, and the energy storage material filled is one or a combination of at least two materials such as rocks, sandstone, metal particles, solid bricks, etc.

[0030] When the compressor unit 2 includes multiple compressors, the multiple compressors are in a coaxial series connection form or a split-shaft parallel connection form. In the split-shaft parallel connection form, each split shaft is dynamically connected to the main drive shaft.

[0031] The heat release circulation loop includes a high-temperature heat accumulator 4, a circulation pump 8 and a high-temperature heat exchanger 9, wherein the circulation pump 8, pipeline h, high-temperature heat exchanger 9, pipeline d, the second three-way valve 7, pipeline e, the high-temperature heat accumulator 4, pipeline f, the first three-way valve 6 and pipeline g are connected in sequence.

[0032] The alkali metal thermoelectric conversion circuit includes a high-temperature heat exchanger 9, an alkali metal thermoelectric converter, a second low-temperature heat exchanger 11 and a first electromagnetic pump 10. The outlet of the high-temperature heat exchanger 9 on the heat absorption side is connected to the inlet of the alkali metal thermoelectric converter through a pipeline, the outlet of the alkali metal thermoelectric converter is connected to the inlet of the heat release side of the second low-temperature heat exchanger 11 through a pipeline, and the outlet of the heat release side of the second low-temperature heat exchanger 11 is connected to the inlet of the heat absorption side of the high-temperature heat exchanger 9 through a pipeline. The first electromagnetic pump 10 is installed on the pipeline through which the alkali metal element passes, and is arranged between the second low-temperature heat exchanger 11 and the high-temperature heat exchanger 9, and is used to control the flow of the alkali metal element in the pipeline and pump the cooled liquid alkali metal element back into the alkali metal thermoelectric converter.

[0033] like Figure 2 As shown, the alkali metal thermoelectric converter includes an alkali metal channel 12 and a base diaphragm 13 disposed in the middle of the alkali metal channel, which divides the alkali metal thermoelectric converter into a high-temperature evaporation zone and a low-temperature condensation zone. Both sides of the base diaphragm 13 are connected to an external load through a wire loop. The base diaphragm 13 is composed of a solid electrolyte containing aluminum oxide and a porous electrode.

[0034] The circulating working medium used in the alkali metal thermoelectric conversion circuit in this embodiment is Na metal element. The Na metal element is transported from the cooling end to the heating end by the operation of the first electromagnetic pump 10, completing the circulation of the working medium in the alkali metal thermoelectric converter. The material used in the alkali metal thermoelectric converter is stainless steel.

[0035] The two ends of the high-temperature heat accumulator 4 are respectively connected to the three-way valves, the other two ends of the first three-way valve 6 are respectively connected to the inlet of the circulation pump 8 and the outlet of the compressor unit 2, and the other two ends of the second three-way valve 7 are respectively connected to the inlet of the expansion unit 3 and the outlet of the heat release side of the high-temperature heat exchanger 9.

[0036] When storing electricity, the three-way valve controls the heat pump heating energy storage circuit to open and the heat release circulation circuit to close. The driving unit 1 of the heat pump heating energy storage circuit drives the coaxial compressor unit 2 and expansion unit 3 to operate, and the circulating gas working medium at normal temperature and low pressure enters the compressor unit 2 and is compressed to a high temperature and high pressure state; then, the high temperature heat energy is stored in the heat storage medium through the high temperature heat accumulator 4, and becomes the circulating gas working medium at normal temperature and high pressure, and further expands and cools down to low temperature and low pressure through the expansion unit 3; the low temperature and low pressure circulating gas working medium passes through the first low temperature heat exchanger 5, absorbs heat from the environment, and raises the temperature of the low temperature and low pressure circulating gas working medium to normal temperature. The circulating gas working medium at normal temperature and low pressure re-enters the inlet of the compressor unit 2 to participate in the heat pump cycle, and the cycle repeats, continuously storing the high temperature heat energy in the heat storage medium of the high temperature heat accumulator 4.

[0037] When generating electricity, the three-way valve controls the heat release circulation loop to be opened and the heat pump heating energy storage loop to be closed. At this time, the alkali metal thermoelectric conversion loop generates electricity. The circulation pump 8 transmits high-temperature heat energy to the high-temperature heat exchanger 9, and the high-temperature heat exchanger 9 transmits heat energy to the alkali metal thermoelectric converter. The operating temperature of the alkali metal thermoelectric converter is 600-1100°C. Na metal forms high-pressure steam at the evaporation end. The Na metal element loses electrons and becomes Na metal ions, and then passes through the Base diaphragm 13 to the cathode side. When the external circuit is connected, the electrons pass through the electrode lead to the cathode side, and are combined with the Na metal ions to obtain electrons and reduced to alkali metal elements. The alkali metal element is transferred to the second low-temperature heat exchanger 11, and the working medium temperature in the second low-temperature heat exchanger 11 is 100-500°C. It is cooled and liquefied into liquid sodium at the second low-temperature heat exchanger 11, and returns to the anode of the alkali metal thermoelectric converter under the action of the first electromagnetic pump 10. Through the operation of the first electromagnetic pump 10, the alkali metal element is transported from the cooling end to the heating end, completing the circulation of the working medium in the alkali metal thermoelectric converter. At the same time, in the external circuit, electrons are transferred from the negative electrode to the positive electrode to realize energy conversion. Through the above process, the alkali metal thermoelectric conversion circuit continuously converts high-temperature thermal energy directly into electrical energy output.

[0038] Example 2

[0039] Reference Figure 3 , is a heat pump energy storage system based on alkali metal thermoelectric conversion described in this embodiment, including a heat pump heating energy storage circuit, a heat release circulation circuit, and an alkali metal thermoelectric conversion circuit, wherein the heat pump heating energy storage circuit and the heat release circulation circuit have the same structures as in Example 1.

[0040] The alkali metal thermoelectric conversion circuit includes a high-temperature heat exchanger 9, an alkali metal thermoelectric converter, a second low-temperature heat exchanger 11, a distillation separation chamber 16 and two electromagnetic pumps, wherein the alkali metal thermoelectric converter includes an alkali metal channel 12, a molten alloy channel 18 and a Base diaphragm 13 arranged in the middle of the channel, the Base diaphragm 13 is composed of a solid electrolyte and a porous electrode, and the two sides of the Base diaphragm 13 are respectively sodium metal element and a molten alloy of sodium. The molten alloy used in this embodiment is a Na-Pb alloy. The two ends of the high-temperature heat exchanger 9 are connected to the distillation separation chamber 16 and the alkali metal thermoelectric converter through pipelines, respectively. The alkali metal thermoelectric converter is connected to the inlet of the distillation separation chamber 16 through pipeline n, and the outlet of the distillation separation chamber 16 is connected to the inlet of the alkali metal thermoelectric converter through pipeline m. A first electromagnetic pump 10 is arranged on the pipeline after the outlet of the distillation separation chamber 16. The distillation separation chamber 16 and the first electromagnetic pump 10 are heated in the heating space 21; the outlet of the distillation separation chamber 16 is connected to the inlet of the heat release side of the second low-temperature heat exchanger 11 through pipeline o, and the outlet of the heat release side of the second low-temperature heat exchanger 11 is connected to the alkali metal thermoelectric converter through a pipeline, and a second electromagnetic pump 20 is arranged on the pipeline after the outlet of the second low-temperature heat exchanger 11. The pipeline where the second electromagnetic pump 20 is located transfers heat through the second low-temperature heat exchanger 11.

[0041] During power generation, the high temperature required for the normal operation of the alkali metal channel 12, the molten alloy channel 18 and the distillation separation chamber 16 is provided by the heating space 21. Since the sodium ions of the liquid working fluid on both sides of the Base diaphragm 13 migrate from the side with high activity, through the Base diaphragm 13 to the side with lower activity, i.e., the liquid molten Na-Pb alloy electrode side, when the external circuit is connected, the electrons pass from the liquid working fluid sodium side through the electrode lead to the external load and then return to the liquid molten Na-Pb alloy electrode side to recombine with the sodium ions. This process continues until the chemical potential gradient on both sides of the diaphragm and the effect of the electric field strength on the sodium ions are balanced. As the reaction proceeds, the concentration of sodium in the liquid molten Na-Pb alloy gradually increases. At this time, the liquid molten Na-Pb alloy enters the distillation separation chamber 16 through the pipeline n. Under the high temperature of the heating space 21, the sodium element is separated from the liquid molten alloy. The separated sodium vapor is condensed in the second low-temperature heat exchanger 11 through the pipeline o and becomes liquid sodium. It is sent into the alkali metal channel 12 by the second electromagnetic pump 20 and heated by the heating space 21, thereby maintaining the circulation of the working medium sodium in the thermoelectric conversion circuit. The remaining concentrated liquid molten Na-Pb in the distillation separation chamber 16 is pumped back to the molten alloy channel 18 through the first electromagnetic pump 10 and the pipeline m. In this embodiment, through the above process, the alkali metal thermoelectric conversion circuit continuously converts high-temperature thermal energy directly into electrical energy output.

[0042] Example 3

[0043] Reference Figure 4, is a heat pump power storage system based on alkali metal thermoelectric conversion described in this embodiment, including a heat pump heating energy storage circuit, a heat release circulation circuit, and an alkali metal thermoelectric conversion circuit. On the basis of Example 1, a sodium-sulfur battery group 15 is connected to the heat absorption side of the second low-temperature heat exchanger 11, and the sodium element in the alkali metal thermoelectric converter transfers heat to the sodium-sulfur battery group 15 through the second low-temperature heat exchanger 11, so that the sodium-sulfur battery group 15 reaches the operating temperature. The sodium-sulfur battery group 15 is placed in the second heating space 14, and the second heating space 14 realizes temperature control through heat transfer with the second low-temperature heat exchanger 11.

Claims

1. A heat pump power storage system based on alkali metal thermoelectric conversion, characterized in that: It includes a heat pump heating energy storage circuit, a heat release circulation circuit and an alkali metal thermoelectric conversion circuit. The heat pump heating energy storage circuit stores high-temperature thermal energy and transfers the high-temperature thermal energy to the alkali metal thermoelectric conversion circuit through the heat release circulation circuit. The alkali metal thermoelectric conversion circuit converts the high-temperature thermal energy into electrical energy by controlling the movement of the alkali metal element. The alkali metal thermoelectric conversion circuit comprises a high-temperature heat exchanger (9), an alkali metal thermoelectric converter, a second low-temperature heat exchanger (11) and a first electromagnetic pump (10); the outlet of the high-temperature heat exchanger (9) on the heat absorption side is connected to the inlet of the alkali metal thermoelectric converter via a pipeline; the outlet of the alkali metal thermoelectric converter is connected to the inlet of the second low-temperature heat exchanger (11) on the heat release side via a pipeline; the outlet of the second low-temperature heat exchanger (11) on the heat release side is connected to the inlet of the high-temperature heat exchanger (9) on the heat absorption side via a pipeline; the first electromagnetic pump (10) is installed on a pipeline through which the alkali metal single substance passes; the first electromagnetic pump (10) is arranged between the second low-temperature heat exchanger (11) and the high-temperature heat exchanger (9).

2. The heat pump power storage system according to claim 1, characterized in that: The alkali metal thermoelectric converter comprises an alkali metal channel (12) and a base diaphragm (13) arranged in the middle of the alkali metal channel, and both sides of the base diaphragm (13) are connected to an external load through a wire loop.

3. The heat pump power storage system according to claim 2, characterized in that: The base diaphragm (13) is composed of a solid electrolyte containing aluminum oxide and a porous electrode.

4. The heat pump power storage system according to claim 1, characterized in that: The heat pump heating energy storage circuit comprises a drive unit (1), a compressor unit (2), a high-temperature heat accumulator (4), an expansion unit (3) and a first low-temperature heat exchanger (5); the drive unit (1) is connected to the compressor unit (2) and the expansion unit (3) through a common transmission shaft; the outlet of the compressor unit (2) is connected to the inlet of the high-temperature heat accumulator (4) through a pipeline; the outlet of the high-temperature heat accumulator (4) is connected to the inlet of the expansion unit (3) through a pipeline; the outlet of the expansion unit (3) is connected to the inlet of the heat release side of the first low-temperature heat exchanger (5) through a pipeline; and the outlet of the heat release side of the first low-temperature heat exchanger (5) is connected to the inlet of the compressor unit (2) through a pipeline.

5. The heat pump power storage system according to claim 1, characterized in that: The heat release circulation loop comprises a high-temperature heat accumulator (4), a circulation pump (8) and a high-temperature heat exchanger (9); the outlet of the high-temperature heat accumulator (4) is connected to the inlet of the heat release side of the high-temperature heat exchanger (9) via a pipeline; the circulation pump (8) is arranged on the pipeline behind the outlet of the high-temperature heat accumulator (4); and the outlet of the heat release side of the high-temperature heat exchanger (9) is connected to the inlet of the high-temperature heat accumulator (4) via a pipeline.

6. The heat pump power storage system according to claim 5, characterized in that: The two ends of the high-temperature heat accumulator (4) are respectively connected to a first three-way valve (6) and a second three-way valve (7); the other two ends of the first three-way valve (6) are respectively connected to the inlet of the circulation pump (8) and the outlet of the compressor unit (2); the other two ends of the second three-way valve (7) are respectively connected to the inlet of the expansion unit (3) and the outlet of the heat release side of the high-temperature heat exchanger (9); when storing electricity, the three-way valve controls the heat pump heating energy storage circuit to be opened and the heat release circulation circuit to be closed; when generating electricity, the three-way valve controls the heat release circulation circuit to be opened and the heat pump heating energy storage circuit to be closed.

7. The heat pump power storage system according to claim 1, characterized in that: The working fluid used in the alkali metal thermoelectric converter is sodium or potassium, or one of sodium-potassium alloy, Na-Pb alloy, and Na-Sn alloy, or a mixture of at least two of the alloys.

8. The heat pump power storage system according to any one of claims 1 to 7, characterized in that: The operating temperature of the alkali metal thermoelectric converter is 600-1100°C, and the working medium temperature in the low-temperature heat exchanger is 100-500°C.

9. The heat pump power storage system according to claim 2 or 3, characterized in that: The alkali metal thermoelectric conversion circuit also includes a distillation separation chamber (16), the two sides of the Base diaphragm (13) are sodium metal and a molten alloy of sodium respectively, the alkali metal thermoelectric converter is connected to the inlet of the distillation separation chamber (16) through a pipeline, and the outlet of the distillation separation chamber (16) is connected to the inlet of the alkali metal thermoelectric converter through a pipeline, the first electromagnetic pump (10) is arranged on the pipeline after the outlet of the distillation separation chamber (16), and the distillation separation chamber (16) and the first electromagnetic pump (10) are heated in the first heating space (21); the outlet of the distillation separation chamber (16) is connected to the inlet of the heat release side of the second low-temperature heat exchanger (11) through a pipeline, the outlet of the heat release side of the second low-temperature heat exchanger (11) is connected to the alkali metal thermoelectric converter through a pipeline, and the second electromagnetic pump (20) is arranged on the pipeline after the outlet of the heat release side of the second low-temperature heat exchanger (11).

10. The heat pump power storage system according to claim 1, characterized in that: The heat absorbing side of the second low-temperature heat exchanger (11) is connected to a sodium-sulfur battery group (15), and the sodium-sulfur battery group (15) is connected to a second heating space (14), and heat is transferred between the second heating space (14) and the second low-temperature heat exchanger (11).

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