Large-temperature-span Carnot battery system based on multi-cycle cascade and operation method of large-temperature-span Carnot battery system

Abstract

The invention relates to the technical field of energy storage, and discloses a multi-cycle cascade-based high-temperature cross-Carnot battery system, which comprises an absorption subsystem for realizing waste heat absorption and release through solution circulation and coupling with a medium-temperature heat / cold storage unit to adjust medium-temperature energy storage; the steam compression cycle subsystem realizes low-temperature refrigeration cycle through a multi-stage compression-expansion process of an organic working medium to form low-temperature cold energy storage; the Brayton reverse circulation subsystem breaks through the temperature limitation of a heat storage medium through reverse circulation compression and expansion of a gas working medium, and energy is converted into high-temperature heat energy to be stored; and the Stirling cycle subsystem is used for directly converting the stored high-temperature heat energy and low-temperature cold energy into electric energy through a temperature difference driving mechanism and outputting the electric energy. The novel large-temperature cross-Carnot battery system provided by the invention meets the demand of cross-space-time scheduling of source (namely source)-load (namely load), and stabilizes the peak-valley difference caused by the electricity load.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and particularly to a large-temperature-crossing Carnot battery system based on multi-cycle cascade and an operation method thereof. Background Art

[0002] A Carnot battery, also known as a heat pump energy storage, uses surplus electricity to drive the charging process, stores electricity in the form of heat energy, and when electricity is needed, the power generation process drives a heat cycle to generate electricity through the stored heat energy to achieve power conversion. Conventional Carnot battery systems pay more attention to the heat storage temperature rather than the cold storage temperature. Further reducing the cold storage temperature, i.e., the heat sink temperature of the power cycle, can improve the electrical energy output characteristics of the power cycle.

[0003] In the high-temperature heat storage stage, taking the vapor compression cycle based on organic working fluids as an example, its heating capacity is limited by the thermal stability of the working fluid; if a reverse Brayton cycle is used, a greater heating capacity means a greater boost in pressure, resulting in poor system performance. In the low-temperature cold storage stage, the problems of using only an absorption refrigeration cycle, a vapor compression refrigeration cycle, or a reverse Brayton cycle are the same as those in the high-temperature heat storage stage.

[0004] The power cycle of a Carnot battery usually adopts an organic Rankine cycle and a Brayton cycle, etc., and the heat transfer pinch point between it and the heat source / heat sink limits the power output performance of the Carnot battery. The ideal Stirling cycle has an isothermal process and may approach the Carnot efficiency in some cases. However, the application research of the Stirling cycle in Carnot batteries remains to be carried out.

[0005] Improving the temperature zone matching of each sub-cycle through multi-cycle cascade, enhancing the power output characteristics of the Carnot battery using the Stirling cycle, further increasing the heat storage temperature, reducing the cold storage temperature, and improving the round-trip efficiency of the Carnot battery are key problems that need to be solved urgently. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems of low round-trip efficiency and low energy storage grade in the existing conventional Carnot battery system, and to propose a large-temperature-crossing Carnot battery system based on multi-cycle cascade.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A large-temperature-crossing Carnot battery system based on multi-cycle cascade includes:

[0009] An absorption sub-system that realizes waste heat absorption and release through solution circulation and is coupled with a medium-temperature heat storage / cold unit to regulate medium-temperature energy storage;

[0010] A vapor compression cycle sub-system that realizes a low-temperature refrigeration cycle through a multi-stage compression-expansion process of an organic working fluid to form low-temperature cold energy storage;

[0011] The Brayton reverse cycle subsystem breaks through the temperature limit of the heat storage medium through the reverse cycle compression and expansion of the gas working medium, and converts energy into high-temperature thermal energy for storage.

[0012] The Stirling cycle subsystem directly converts the stored high-temperature thermal energy and low-temperature cold energy into electrical energy output through a temperature difference driving mechanism.

[0013] Preferably, the absorption subsystem includes a generator, a condenser, a first throttle valve, an evaporator, an absorber, a solution pump, a regenerator, a first circulation pump, a high-temperature buffer tank, a second circulation pump, a low-temperature buffer tank, a first control valve, a second control valve, a third control valve, a fourth control valve, and a third circulation pump;

[0014] The refrigerant-side outlet of the generator is connected to the refrigerant-side inlet of the condenser, and the concentrated absorbent-side outlet is connected to the concentrated absorbent-side inlet of the regenerator;

[0015] The refrigerant-side outlet of the condenser is connected to the inlet of the first throttle valve, and the outlet of the first throttle valve is connected to the refrigerant-side inlet of the evaporator;

[0016] The refrigerant-side outlet of the evaporator is connected to the refrigerant-side inlet of the absorber, the concentrated absorbent-side inlet of the absorber is connected to the concentrated absorbent-side outlet of the regenerator, the dilute solution-side outlet is connected to the dilute absorbent-side inlet of the regenerator through a solution pump, and the dilute absorbent-side outlet of the regenerator is connected to the dilute absorbent-side inlet of the generator;

[0017] The heat transfer oil-side outlet of the condenser is connected to the inlet of the high-temperature buffer tank through a first circulation pump, and the outlet of the high-temperature buffer tank forms a closed loop with the heat transfer oil-side inlet of the condenser;

[0018] The heat transfer oil-side outlet of the evaporator is connected to the inlet of the low-temperature buffer tank, and the outlet of the low-temperature buffer tank forms a closed loop with the heat transfer oil-side inlet of the evaporator through a second circulation pump.

[0019] Preferably, the energy storage medium outlet of the high-temperature buffer tank is connected to the inlet of the third circulation pump through a first control valve, and the outlet of the third circulation pump is connected to the energy storage medium-side inlet of the first heat exchanger;

[0020] The energy storage medium-side outlet of the first heat exchanger is respectively connected to the energy storage medium inlet of the high-temperature buffer tank and the energy storage medium inlet of the low-temperature buffer tank through a second control valve and a fourth control valve;

[0021] The outlet of the third control valve is connected in parallel to the inlet of the third circulation pump, and is used to adjust the distribution path of the energy storage medium between the high-temperature buffer tank and the low-temperature buffer tank;

[0022] The energy storage medium of the absorption subsystem exchanges heat with the vapor compression cycle subsystem or the Brayton reverse cycle subsystem through the first heat exchanger to achieve the storage and release of thermal energy in the medium temperature range.

[0023] Preferably, the vapor compression cycle subsystem includes a first heat exchanger, a fifth control valve, a second throttle valve, a sixth control valve, a seventh control valve, a first compressor, an eighth control valve, a ninth control valve, a third throttle valve, a tenth control valve, an eleventh control valve, a second compressor, a twelfth control valve, and a second heat exchanger;

[0024] The organic working fluid side outlet / import of the first heat exchanger is respectively connected to the import of the fifth control valve and the outlet of the seventh control valve;

[0025] The outlet of the fifth control valve is connected to the import of the second throttle valve, and the outlet of the second throttle valve is connected to the import of the sixth control valve;

[0026] The import of the seventh control valve is connected to the outlet of the first compressor, and the import of the first compressor is connected to the outlet of the eighth control valve;

[0027] The outlet of the sixth control valve and the import of the eighth control valve are jointly connected to the organic working fluid side import / outlet of the second heat exchanger;

[0028] The organic working fluid side outlet / import of the second heat exchanger is respectively connected to the outlet of the tenth control valve and the import of the twelfth control valve;

[0029] The import of the tenth control valve is connected to the outlet of the third throttle valve, and the import of the third throttle valve is connected to the outlet of the ninth control valve;

[0030] The outlet of the twelfth control valve is connected to the import of the second compressor, and the outlet of the second compressor is connected to the import of the eleventh control valve;

[0031] The import of the ninth control valve and the outlet of the eleventh control valve are jointly connected to the organic working fluid side import / outlet of the first heat exchanger to form a closed-loop working fluid circulation loop.

[0032] Preferably, the Brayton reverse cycle subsystem includes a thirteenth control valve, a first expander, a fourteenth control valve, a fifteenth control valve, a third compressor, a sixteenth control valve, a seventeenth control valve, a second expander, an eighteenth control valve, a nineteenth control valve, a fourth compressor, a twentieth control valve, and a third heat exchanger;

[0033] The gas side outlet / inlet of the second heat exchanger is respectively connected to the inlet of the thirteenth control valve and the outlet of the fifteenth control valve. The outlet of the thirteenth control valve is connected to the inlet of the first expander. The outlet of the first expander is connected to the inlet of the fourteenth control valve. The inlet of the fifteenth control valve is connected to the outlet of the third compressor. The inlet of the third compressor is connected to the outlet of the sixteenth control valve. The outlet of the fourteenth control valve and the inlet of the sixteenth control valve are respectively connected to the gas side inlet / outlet of the third heat exchanger. The organic working fluid side outlet / inlet of the third heat exchanger is respectively connected to the outlet of the eighteenth control valve and the inlet of the twentieth control valve. The inlet of the eighteenth control valve is connected to the outlet of the second expander. The inlet of the second expander is connected to the outlet of the seventeenth control valve. The outlet of the twentieth control valve is connected to the inlet of the fourth compressor. The outlet of the fourth compressor is connected to the inlet of the nineteenth control valve. The inlet of the seventeenth control valve and the outlet of the nineteenth control valve are respectively connected to the gas side inlet / outlet of the second heat exchanger.

[0034] Preferably, the Stirling cycle subsystem includes a twenty-first control valve, a high-temperature heat storage tank, a twenty-second control valve, a twenty-third control valve, a low-temperature cold storage tank, a twenty-fourth control valve, a fourth circulation pump, a twenty-fifth control valve, a twenty-sixth control valve, a twenty-seventh control valve, a twenty-eighth control valve, and a Stirling generator;

[0035] The heat transfer oil side outlet of the third heat exchanger is connected to the inlet of the twenty-first control valve and the inlet of the twenty-third control valve. The outlet of the twenty-first control valve is connected to the heat transfer oil inlet of the high-temperature heat storage tank. The heat transfer oil outlet of the high-temperature heat storage tank is connected to the inlet of the twenty-second control valve. The outlet of the twenty-third control valve is connected to the heat transfer oil inlet of the low-temperature cold storage tank. The heat transfer oil outlet of the low-temperature cold storage tank is connected to the inlet of the twenty-fourth control valve. The outlets of the twenty-second control valve and the twenty-fourth control valve are connected to the inlet of the fourth circulation pump. The outlet of the fourth circulation pump is connected to the heat transfer oil side inlet of the third heat exchanger. The heat storage medium outlet of the high-temperature heat storage tank is connected to the inlet of the twenty-fifth control valve. The outlet of the twenty-fifth control valve is connected to the heat-receiving side inlet of the Stirling generator. The heat-receiving side outlet of the Stirling generator is connected to the inlet of the twenty-sixth control valve. The outlet of the twenty-sixth control valve is connected to the heat storage medium inlet of the high-temperature heat storage tank. The cold storage medium outlet of the low-temperature cold storage tank is connected to the inlet of the twenty-seventh control valve. The outlet of the twenty-seventh control valve is connected to the cold-receiving side inlet of the Stirling generator. The cold-receiving side outlet of the Stirling generator is connected to the inlet of the twenty-eighth control valve. The outlet of the twenty-eighth control valve is connected to the cold storage medium inlet of the low-temperature cold storage tank.

[0036] Preferably, the reverse Brayton cycle subsystem can flexibly adjust its operation mode by adjusting the opening and closing of the control valves, convert the heat or cold in the high-temperature buffer tank and the low-temperature buffer tank into high-temperature heat energy or low-temperature cold energy for storage, and the proportion can be flexibly adjusted.

[0037] An operating method for a large-temperature transcarnot battery system based on multi-cycle cascade, which is applied to a large-temperature transcarnot battery system based on multi-cycle cascade, includes:

[0038] Heat storage mode:

[0039] In the vapor compression cycle subsystem, the fifth control valve, the sixth control valve, the eleventh control valve, and the twelfth control valve are closed. In the Brayton reverse cycle subsystem, the thirteenth control valve, the fourteenth control valve, the nineteenth control valve, and the twentieth control valve are closed. The Stirling generator stops operating;

[0040] The heat storage process is as follows: The heat storage medium enters the third circulation pump via the first control valve from the high-temperature buffer tank, then enters the first heat exchanger, and after flowing out of the first heat exchanger, returns to the high-temperature buffer tank via the second control valve, and this cycle repeats; After the organic working fluid exchanges heat with the heat storage medium in the first heat exchanger, it enters the first compressor via the seventh control valve. The superheated steam flowing out of the first compressor enters the second heat exchanger via the eighth control valve to release heat and become liquid. The liquid working fluid enters the third throttle valve via the tenth control valve to reduce the temperature and pressure, and then enters the first heat exchanger via the ninth control valve, and this cycle repeats; After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger, it enters the third compressor via the fifteenth control valve. The high-temperature and high-pressure gas working fluid flowing out of the third compressor enters the third heat exchanger via the sixteenth control valve to release heat. The low-temperature and high-pressure gas working fluid enters the second expander via the eighteenth control valve to reduce the temperature and pressure, and then enters the second heat exchanger via the seventeenth control valve, and this cycle repeats; After the heat-conducting oil absorbs heat in the third heat exchanger, it enters the high-temperature heat storage tank via the twenty-first control valve to heat the heat storage medium, and then enters the fourth circulation pump via the twenty-second control valve, and then returns to the third heat exchanger, and this cycle repeats;

[0041] Electric energy is consumed by the first compressor and the third compressor and converted into high-temperature heat energy and stored in the high-temperature heat storage tank;

[0042] Cooling storage mode:

[0043] In the vapor compression cycle subsystem, the seventh control valve, the eighth control valve, the ninth control valve, and the tenth control valve are closed. In the Brayton reverse cycle subsystem, the fifteenth control valve, the sixteenth control valve, the seventeenth control valve, and the eighteenth control valve are closed. The Stirling generator stops operating;

[0044] The cold storage process is as follows: The cold storage medium enters the third circulation pump from the low-temperature buffer tank via the third control valve, then enters the first heat exchanger, and after flowing out of the first heat exchanger, it returns to the low-temperature buffer tank via the fourth control valve, and this cycle repeats; after the organic working fluid exchanges heat with the cold storage medium in the first heat exchanger, it enters the second throttle valve via the fifth control valve, and the low-temperature and low-pressure working fluid flowing out of the second throttle valve enters the second heat exchanger to absorb heat and become gaseous via the sixth control valve. The gaseous working fluid enters the second compressor to increase the temperature and pressure via the twelfth control valve, and then enters the first heat exchanger via the eleventh control valve, and this cycle repeats; after the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger, it enters the first expander via the thirteenth control valve. The low-temperature and low-pressure gas working fluid flowing out of the first expander enters the third heat exchanger to absorb heat via the fourteenth control valve. The high-temperature and low-pressure gas working fluid enters the fourth compressor to increase the temperature and pressure via the twentieth control valve, and then enters the second heat exchanger via the nineteenth control valve, and this cycle repeats; after the heat-conducting oil exchanges heat in the third heat exchanger, it enters the low-temperature cold storage tank via the twenty-third control valve to heat the cold storage medium, then enters the fourth circulation pump via the twenty-fourth control valve, and then returns to the third heat exchanger, and this cycle repeats;

[0045] Electric energy is consumed by the second compressor and the fourth compressor, and is converted into high-temperature heat energy and stored in the high-temperature heat storage tank.

[0046] Preferably, it further includes an energy release strategy:

[0047] In the absorption subsystem, the first control valve, the second control valve, the third control valve, and the fourth control valve are all closed;

[0048] In the vapor compression refrigeration cycle subsystem, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, the ninth control valve, the tenth control valve, the eleventh control valve, and the twelfth control valve are all closed;

[0049] In the Brayton reverse cycle subsystem, the thirteenth control valve, the fourteenth control valve, the fifteenth control valve, the sixteenth control valve, the seventeenth control valve, the eighteenth control valve, the nineteenth control valve, and the twentieth control valve are all closed;

[0050] In the Stirling cycle subsystem, the twenty-first control valve, the twenty-second control valve, the twenty-third control valve, and the twenty-fourth control valve are all closed. The high-temperature heat storage medium enters the heating surface of the Stirling engine via the twenty-fifth control valve, and then returns to the high-temperature heat storage tank via the twenty-sixth control valve. The low-temperature cold storage medium enters the cooling surface of the Stirling engine via the twenty-seventh control valve, and then returns to the low-temperature cold storage tank via the twenty-eighth control valve. The Stirling generator converts the stored heat energy and cold energy into electrical energy and outputs it under the drive of the temperature difference.

[0051] Preferably, for the demand scenarios of power consumption and waste heat storage during the cooling season, an energy storage strategy is adopted to supplement the heat exchanger of the low-temperature buffer tank to supply cooling to users;

[0052] For the demand scenario of power grid peak shaving during the cooling season, an energy release strategy is adopted to supplement the heat exchanger of the low-temperature cold storage tank to supply cooling to users;

[0053] For the demand scenario of power consumption during the heating season, an energy storage strategy is adopted to flexibly regulate the heat output of industrial waste heat and the high-temperature buffer tank to supply heat to users;

[0054] For the demand scenario of power grid peak shaving during the heating season, an energy release strategy is adopted to flexibly regulate the heat output of industrial waste heat and the high-temperature heat storage tank to supply heat to users.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] 1. The present invention superimposes multiple cycles and first proposes a new type of large-temperature-span Carnot battery system, which is applied to energy storage, and can solve problems such as poor energy storage grade, small cold and heat storage temperature difference, and low round-trip efficiency of conventional energy storage;

[0057] 2. Due to the stability of the gas working medium at high temperatures in the reverse Brayton cycle, the heat storage temperature of the present invention is only limited by the properties of the container material, breaking through the limitations of the heat storage medium;

[0058] 3. Through multiple refrigerations, the cold storage temperature is effectively reduced;

[0059] 4. It meets the demand for cross-time air-conditioning scheduling of the source (i.e., the source)-load (i.e., the load), and smooths the peak-valley difference caused by the electrical load. Description of the Drawings

[0060] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0061] Figure 2 It is a schematic diagram of the energy storage (cold) mode of the system of the present invention;

[0062] Figure 3 It is a schematic diagram of the energy storage (heat) mode of the system of the present invention;

[0063] Figure 4 It is a schematic diagram of the energy release mode of the system of the present invention.

[0064] In the figure: 1. Generator; 2. Condenser; 3. First throttle valve; 4. Evaporator; 5. Absorber; 6. Solution pump; 7. Regenerator; 8. First circulation pump; 9. High-temperature buffer tank; 10. Second circulation pump; 11. Low-temperature buffer tank; 12. First control valve; 13. Second control valve; 14. Third control valve; 15. Fourth control valve; 16. Third circulation pump; 17. First heat exchanger; 18. Fifth control valve; 19. Second throttle valve; 20. Sixth control valve; 21. Seventh control valve; 22. First compressor; 23. Eighth control valve; 24. Ninth control valve; 25. Third throttle valve; 26. Tenth control valve; 27. Eleventh control valve; 28. Second compressor; 29. Twelfth control valve; 30. Second heat exchanger; 31. Thirteenth control valve; 32. First expander; 33. Fourteenth control valve; 34. Fifteenth control valve; 35. Third compressor; 36. Sixteenth control valve; 37. Seventeenth control valve; 38. Second expander; 39. Eighteenth control valve; 40. Nineteenth control valve; 41. Fourth compressor; 42. Twentieth control valve; 43. Third heat exchanger; 44. Twenty-first control valve; 45. High-temperature heat storage tank; 46. Twenty-second control valve; 47. Twenty-third control valve; 48. Low-temperature cold storage tank; 49. Twenty-fourth control valve; 50. Fourth circulation pump; 51. Twenty-fifth control valve; 52. Twenty-sixth control valve; 53. Twenty-seventh control valve; 54. Twenty-eighth control valve; 55. Stirling generator. Specific embodiments

[0065] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0066] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0067] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0068] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0069] As Figures 1-4 shown, a large-temperature-span Carnot battery system based on multi-cycle cascade includes an absorption subsystem, a vapor compression cycle subsystem, a Brayton reverse cycle subsystem, and a Stirling cycle subsystem;

[0070] The absorption subsystem includes a generator 1, a condenser 2, a first throttle valve 3, an evaporator 4, an absorber 5, a solution pump 6, a regenerator 7, a first circulation pump 8, a high-temperature buffer tank 9, a second circulation pump 10, a low-temperature buffer tank 11, a first control valve 12, a second control valve 13, a third control valve 14, a fourth control valve 15, and a third circulation pump 16;

[0071] The refrigerant-side outlet of the generator 1 is connected to the refrigerant-side inlet of the condenser 2, the concentrated absorbent-side outlet of the generator 1 is connected to the concentrated absorbent-side inlet of the regenerator 7, the refrigerant-side outlet of the condenser 2 is connected to the inlet of the first throttle valve 3, the outlet of the first throttle valve 3 is connected to the refrigerant-side inlet of the evaporator 4, the refrigerant-side outlet of the evaporator 4 is connected to the refrigerant-side inlet of the absorber 5, the concentrated absorbent-side inlet of the absorber 5 is connected to the concentrated absorbent-side outlet of the regenerator 7, the dilute solution-side outlet of the absorber 5 is connected to the inlet of the solution pump 6, the outlet of the solution pump 6 is connected to the dilute absorbent-side inlet of the regenerator 7, the dilute absorbent-side outlet of the regenerator 7 is connected to the dilute absorbent-side inlet of the generator 1, the heat transfer oil-side outlet of the condenser 2 is connected to the inlet of the first circulation pump 8, the outlet of the first circulation pump 8 is connected to the inlet of the high-temperature buffer tank 9, the outlet of the high-temperature buffer tank 9 is connected to the heat transfer oil-side inlet of the condenser 2, the heat transfer oil-side outlet of the evaporator 4 is connected to the inlet of the low-temperature buffer tank 11, the outlet of the low-temperature buffer tank 11 is connected to the inlet of the second circulation pump 10, the outlet of the second circulation pump 10 is connected to the heat transfer oil-side inlet of the evaporator 4, the energy storage medium outlet of the high-temperature buffer tank 9 is connected to the inlet of the first control valve 12, the outlet of the first control valve 12 and the outlet of the third control valve 14 are connected to the inlet of the third circulation pump 16, the outlet of the third circulation pump 16 is connected to the energy storage medium-side inlet of the first heat exchanger 17, the energy storage medium-side outlet of the first heat exchanger 17 is connected to the inlet of the second control valve 13 and the inlet of the fourth control valve 15, the outlet of the second control valve 13 is connected to the energy storage medium inlet of the high-temperature buffer tank 9, and the outlet of the fourth control valve 15 is connected to the energy storage medium inlet of the low-temperature buffer tank 11.

[0072] The vapor compression cycle subsystem includes a first heat exchanger 17, a fifth control valve 18, a second throttle valve 19, a sixth control valve 20, a seventh control valve 21, a first compressor 22, an eighth control valve 23, a ninth control valve 24, a third throttle valve 25, a tenth control valve 26, an eleventh control valve 27, a second compressor 28, a twelfth control valve 29, and a second heat exchanger 30.

[0073] The organic working fluid side outlet / inlet of the first heat exchanger 17 is connected to the inlet of the fifth control valve 18 and the outlet of the seventh control valve 21. The outlet of the fifth control valve 18 is connected to the inlet of the second throttle valve 19. The outlet of the second throttle valve 19 is connected to the inlet of the sixth control valve 20. The inlet of the seventh control valve 21 is connected to the outlet of the first compressor 22. The inlet of the first compressor 22 is connected to the outlet of the eighth control valve 23. The outlet of the sixth control valve 20 and the inlet of the eighth control valve 23 are connected to the organic working fluid inlet / outlet of the second heat exchanger 30. The organic working fluid side outlet / inlet of the second heat exchanger 30 is connected to the outlet of the tenth control valve 26 and the inlet of the twelfth control valve 29. The inlet of the tenth control valve 26 is connected to the outlet of the third throttle valve 25. The inlet of the third throttle valve 25 is connected to the outlet of the ninth control valve 24. The outlet of the twelfth control valve 29 is connected to the inlet of the second compressor 28. The outlet of the second compressor 28 is connected to the inlet of the eleventh control valve 27. The inlet of the ninth control valve 24 and the outlet of the eleventh control valve 27 are connected to the organic working fluid inlet / outlet of the first heat exchanger 17.

[0074] The Brayton reverse cycle subsystem includes a thirteenth control valve 31, a first expander 32, a fourteenth control valve 33, a fifteenth control valve 34, a third compressor 35, a sixteenth control valve 36, a seventeenth control valve 37, a second expander 38, an eighteenth control valve 39, a nineteenth control valve 40, a fourth compressor 41, a twentieth control valve 42, and a third heat exchanger 43.

[0075] The gas side outlet / inlet of the second heat exchanger 30 is connected to the inlet of the thirteenth control valve 31 and the outlet of the fifteenth control valve 34. The outlet of the thirteenth control valve 31 is connected to the inlet of the first expander 32. The outlet of the first expander 32 is connected to the inlet of the fourteenth control valve 33. The inlet of the fifteenth control valve 34 is connected to the outlet of the third compressor 35. The inlet of the third compressor 35 is connected to the outlet of the sixteenth control valve 36. The outlet of the fourteenth control valve 33 and the inlet of the sixteenth control valve 36 are connected to the gas side inlet / outlet of the third heat exchanger 43. The organic working fluid side outlet / inlet of the third heat exchanger 43 is connected to the outlet of the eighteenth control valve 39 and the inlet of the twentieth control valve 42. The inlet of the eighteenth control valve 39 is connected to the outlet of the second expander 38. The inlet of the second expander 38 is connected to the outlet of the seventeenth control valve 37. The outlet of the twentieth control valve 42 is connected to the inlet of the fourth compressor 41. The outlet of the fourth compressor 41 is connected to the inlet of the nineteenth control valve 40. The inlet of the seventeenth control valve 37 and the outlet of the nineteenth control valve 40 are connected to the gas side inlet / outlet of the second heat exchanger 30.

[0076] The Stirling cycle subsystem includes the twenty - first control valve 44, the high - temperature heat storage tank 45, the twenty - second control valve 46, the twenty - third control valve 47, the low - temperature cold storage tank 48, the twenty - fourth control valve 49, the fourth circulation pump 50, the twenty - fifth control valve 51, the twenty - sixth control valve 52, the twenty - seventh control valve 53, the twenty - eighth control valve 54, and the Stirling generator 55.

[0077] The outlet of the heat transfer oil side of the third heat exchanger 43 is connected to the inlet of the twenty - first control valve 44 and the inlet of the twenty - third control valve 47. The outlet of the twenty - first control valve 44 is connected to the heat transfer oil inlet of the high - temperature heat storage tank 45. The heat transfer oil outlet of the high - temperature heat storage tank 45 is connected to the inlet of the twenty - second control valve 46. The outlet of the twenty - third control valve 47 is connected to the heat transfer oil inlet of the low - temperature cold storage tank 48. The heat transfer oil outlet of the low - temperature cold storage tank 48 is connected to the inlet of the twenty - fourth control valve 49. The outlets of the twenty - second control valve 46 and the twenty - fourth control valve 49 are connected to the inlet of the fourth circulation pump 50. The outlet of the fourth circulation pump 50 is connected to the heat transfer oil side inlet of the third heat exchanger 43. The heat storage medium outlet of the high - temperature heat storage tank 45 is connected to the inlet of the twenty - fifth control valve 51. The outlet of the twenty - fifth control valve 51 is connected to the heated side inlet of the Stirling generator 55. The heated side outlet of the Stirling generator 55 is connected to the inlet of the twenty - sixth control valve 52. The outlet of the twenty - sixth control valve 52 is connected to the heat storage medium inlet of the high - temperature heat storage tank 45. The cold storage medium outlet of the low - temperature cold storage tank 48 is connected to the inlet of the twenty - seventh control valve 53. The outlet of the twenty - seventh control valve 53 is connected to the cooled side inlet of the Stirling generator 55. The cooled side outlet of the Stirling generator 55 is connected to the inlet of the twenty - eighth control valve 54. The outlet of the twenty - eighth control valve 54 is connected to the cold storage medium inlet of the low - temperature cold storage tank 48.

[0078] The Carnot battery system realizes two basic working modes, namely the energy - releasing mode and the energy - storing mode.

[0079] The further technical requirements are as follows:

[0080] In the energy - releasing mode, the absorption subsystem, the vapor compression cycle subsystem, and the Brayton reverse cycle subsystem do not work. The Stirling cycle subsystem converts the stored thermal energy into electrical energy to achieve power grid peak shaving, and at the same time releases heat into the low - temperature cold storage tank to heat the cold storage medium in the low - temperature cold storage tank.

[0081] In the energy - storing mode, the Stirling cycle subsystem does not work. The absorption subsystem absorbs industrial waste heat and converts it into thermal energy at a slightly lower temperature and cold energy at a lower temperature for storage. The vapor compression refrigeration cycle subsystem and the Brayton reverse cycle subsystem respectively convert the thermal energy at a slightly lower temperature and the cold energy at a lower temperature into high - temperature thermal energy at a higher temperature and low - temperature cold energy at a lower temperature, increase the temperature of the high - temperature heat storage medium, and decrease the temperature of the low - temperature cold storage medium to absorb the excess power of the power grid.

[0082] Other energy supply modes can achieve the functions of cooling or heating by adding equipment such as heat exchangers under the inspiration of the present invention.

[0083] Among them, the working medium and cold / heat storage medium of the present invention include, but are not limited to, organic working fluids, carbon dioxide, nitrogen, helium, air, etc.

[0084] Working principle:

[0085] When the grid power is in excess, based on the absorption subsystem, vapor compression refrigeration cycle subsystem, and Brayton reverse cycle subsystem, electrical energy is converted into high-temperature heat energy or low-temperature cold energy to complete the upgrading storage of waste heat and the effective consumption of curtailed power; when the grid power is insufficient, a Stirling engine between the high-temperature heat storage tank 45 and the low-temperature cold storage tank 48 is used to achieve the conversion of heat energy to electrical energy. The present invention utilizes a multi-cycle cascaded Carnot battery energy storage system to store curtailed power in the high-temperature heat storage unit and the low-temperature cold storage unit respectively, which can efficiently consume grid curtailed power and at the same time achieve heat storage and cold storage with a large temperature difference.

[0086] The specific working processes of the three sub-units are described as follows:

[0087] In the energy storage mode, the dilute lithium bromide solution in the generator 1 is heated by industrial waste heat to become water vapor and concentrated lithium bromide solution. The concentrated lithium bromide solution flows into the absorber 5 via the regenerator 7, and the water vapor enters the condenser 2 and is condensed into a liquid state; the liquid water is cooled and depressurized by the first throttle valve 3 and then enters the evaporator 4 to release cold energy to the heat-conducting oil, and itself absorbs heat and becomes a gas state, and then enters the absorber 5 to be absorbed by the concentrated lithium bromide solution, and the concentrated lithium bromide solution becomes dilute lithium bromide solution; the dilute lithium bromide solution enters the regenerator 7 through the solution pump 6 and exchanges heat with the concentrated lithium bromide solution from the generator 1 and then enters the generator 1, absorbs the waste heat to become water vapor and concentrated lithium bromide solution, and so on in a cycle. At the same time, the evaporator 4 stores cold energy in the low-temperature buffer tank 11 by cooling the heat-conducting oil, and the condenser 2 stores heat energy in the high-temperature buffer tank 9 by heating the heat-conducting oil.

[0088] In the energy storage mode, the heat storage process is as follows: The heat storage medium enters the third circulation pump 16 from the high-temperature buffer tank 9 through the first control valve 12, then enters the first heat exchanger 17, and after flowing out of the first heat exchanger 17, it returns to the high-temperature buffer tank 9 through the second control valve 13, and this cycle repeats; after the organic working fluid exchanges heat with the heat storage medium in the first heat exchanger 17, it enters the first compressor 22 through the seventh control valve 21. The superheated steam flowing out of the first compressor 22 enters the second heat exchanger 30 through the eighth control valve 23 and releases heat to become liquid. The liquid working fluid enters the third throttle valve 25 through the tenth control valve 26 to reduce the temperature and pressure, and then enters the first heat exchanger 17 through the ninth control valve 24, and this cycle repeats. After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger 30, it enters the third compressor 35 through the fifteenth control valve 34. The high-temperature and high-pressure gas working fluid flowing out of the third compressor 35 enters the third heat exchanger 43 through the sixteenth control valve 36 to release heat. The low-temperature and high-pressure gas working fluid enters the second expander 38 through the eighteenth control valve 39 to reduce the temperature and pressure, and then enters the second heat exchanger 30 through the seventeenth control valve 37, and this cycle repeats. After the heat-conducting oil absorbs heat in the third heat exchanger 43, it enters the high-temperature heat storage tank 45 through the twenty-first control valve 44 to heat the heat storage medium, and then enters the fourth circulation pump 50 through the twenty-second control valve 46, and then returns to the third heat exchanger 43, and this cycle repeats.

[0089] In the energy storage mode, the cold storage process is as follows: The cold storage medium enters the third circulation pump 16 from the low-temperature buffer tank 11 through the third control valve 14, then enters the first heat exchanger 17, and after flowing out of the first heat exchanger 17, it returns to the low-temperature buffer tank 11 through the fourth control valve 15, and this cycle repeats; after the organic working fluid exchanges heat with the cold storage medium in the first heat exchanger 17, it enters the second throttle valve 19 through the fifth control valve 18. The low-temperature and low-pressure working fluid flowing out of the second throttle valve 19 enters the second heat exchanger 30 through the sixth control valve 20 to absorb heat and become gaseous. The gaseous working fluid enters the second compressor 28 through the twelfth control valve 29 to increase the temperature and pressure, and then enters the first heat exchanger 17 through the eleventh control valve 27, and this cycle repeats. After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger 30, it enters the first expander 32 through the thirteenth control valve 31. The low-temperature and low-pressure gas working fluid flowing out of the first expander 32 enters the third heat exchanger 43 through the fourteenth control valve 33 to absorb heat. The high-temperature and low-pressure gas working fluid enters the fourth compressor 41 through the twentieth control valve 42 to increase the temperature and pressure, and then enters the second heat exchanger 30 through the nineteenth control valve 40, and this cycle repeats. After the heat-conducting oil exchanges heat in the third heat exchanger 43, it enters the low-temperature cold storage tank 48 through the twenty-third control valve 47 to heat the cold storage medium, and then enters the fourth circulation pump 50 through the twenty-fourth control valve 49, and then returns to the third heat exchanger 43, and this cycle repeats.

[0090] In the power generation mode of the Carnot battery, the high-temperature heat storage medium enters the heating surface of the Stirling engine 55 through the twenty-fifth control valve 51, and then returns to the high-temperature heat storage tank 45 through the twenty-sixth control valve 52. The low-temperature cold storage medium enters the cooling surface of the Stirling engine 55 through the twenty-seventh control valve 53, and then returns to the low-temperature cold storage tank 48 through the twenty-eighth control valve 54. The Stirling generator 55 converts the stored heat energy and cold energy into electrical energy under the drive of the temperature difference.

[0091] The compressor includes, but is not limited to, a scroll compressor, a screw compressor, a rotary compressor, and a magnetic levitation compressor;

[0092] The expander includes, but is not limited to, a scroll expander, a screw expander, and a rotary expander.

[0093] The heat exchanger includes, but is not limited to, a shell-and-tube heat exchanger, a double-pipe heat exchanger, and a plate heat exchanger.

[0094] The operation method of a large temperature-span Carnot battery system based on multi-cycle cascade includes basic strategies such as energy storage and power generation. Among them, the basic strategies such as energy storage and power generation are specifically as follows:

[0095] Heat storage mode:

[0096] In the vapor compression cycle subsystem, the fifth control valve 18, the sixth control valve 20, the eleventh control valve 27, and the twelfth control valve 29 are closed. In the Brayton reverse cycle subsystem, the thirteenth control valve 31, the fourteenth control valve 33, the nineteenth control valve 40, and the twentieth control valve 42 are closed. The Stirling generator 55 stops operating;

[0097] In the heat storage process of the energy storage mode, the heat storage medium enters the third circulation pump 16 from the high-temperature buffer tank 9 via the first control valve 12, then enters the first heat exchanger 17, and after flowing out of the first heat exchanger 17, returns to the high-temperature buffer tank 9 via the second control valve 13, and this cycle repeats; after the organic working fluid exchanges heat with the heat storage medium in the first heat exchanger 17, it enters the first compressor 22 via the seventh control valve 21. The superheated steam flowing out of the first compressor 22 enters the second heat exchanger 30 via the eighth control valve 23 and releases heat to become liquid. The liquid working fluid enters the third throttle valve 25 via the tenth control valve 26 to reduce the temperature and pressure, and then enters the first heat exchanger 17 via the ninth control valve 24, and this cycle repeats. After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger 30, it enters the third compressor 35 via the fifteenth control valve 34. The high-temperature and high-pressure gas working fluid flowing out of the third compressor 35 enters the third heat exchanger 43 via the sixteenth control valve 36 to release heat. The low-temperature and high-pressure gas working fluid enters the second expander 38 via the eighteenth control valve 39 to reduce the temperature and pressure, and then enters the second heat exchanger 30 via the seventeenth control valve 37, and this cycle repeats. After the heat-conducting oil absorbs heat in the third heat exchanger 43, it enters the high-temperature heat storage tank 45 via the twenty-first control valve 44 to heat the heat storage medium, and then enters the fourth circulation pump 50 via the twenty-second control valve 46, and then returns to the third heat exchanger 43, and this cycle repeats.

[0098] Electric energy is consumed by the first compressor 22 and the third compressor 35 and converted into high-temperature heat energy and stored in the high-temperature heat storage tank 45.

[0099] Cold storage mode:

[0100] In the vapor compression cycle subsystem, the seventh control valve 21, the eighth control valve 23, the ninth control valve 24, and the tenth control valve 26 are closed. In the Brayton reverse cycle subsystem, the fifteenth control valve 34, the sixteenth control valve 36, the seventeenth control valve 37, and the eighteenth control valve 39 are closed. The Stirling generator 55 stops running;

[0101] In the energy storage mode, the cold storage process is as follows: The cold storage medium enters the third circulation pump 16 from the low-temperature buffer tank 11 via the third control valve 14, then enters the first heat exchanger 17, and after flowing out of the first heat exchanger 17, it returns to the low-temperature buffer tank 11 via the fourth control valve 15, and this cycle repeats; After the organic working fluid exchanges heat with the cold storage medium in the first heat exchanger 17, it enters the second throttle valve 19 via the fifth control valve 18. The low-temperature and low-pressure working fluid flowing out of the second throttle valve 19 enters the second heat exchanger 30 via the sixth control valve 20 and absorbs heat to become gaseous. The gaseous working fluid enters the second compressor 28 via the twelfth control valve 29 to increase in temperature and pressure, and then enters the first heat exchanger 17 via the eleventh control valve 27, and this cycle repeats. After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger 30, it enters the first expander 32 via the thirteenth control valve 31. The low-temperature and low-pressure gas working fluid flowing out of the first expander 32 enters the third heat exchanger 43 via the fourteenth control valve 33 to absorb heat. The high-temperature and low-pressure gas working fluid enters the fourth compressor 41 via the twentieth control valve 42 to increase in temperature and pressure, and then enters the second heat exchanger 30 via the nineteenth control valve 40, and this cycle repeats. After the heat-conducting oil exchanges heat in the third heat exchanger 43, it enters the low-temperature cold storage tank 48 via the twenty-third control valve 47 to heat the cold storage medium, then enters the fourth circulation pump 50 via the twenty-fourth control valve 49, and then returns to the third heat exchanger 43, and this cycle repeats.

[0102] Electric energy is consumed by the second compressor 28 and the fourth compressor 41 and converted into high-temperature heat energy and stored in the high-temperature heat storage tank 45.

[0103] The energy release strategy of a large temperature-span Carnot battery system based on multi-cycle cascade is as follows:

[0104] In the absorption subsystem, the first control valve 12, the second control valve 13, the third control valve 14, and the fourth control valve 15 are all closed;

[0105] In the vapor compression refrigeration cycle subsystem, the fifth control valve 18, the sixth control valve 20, the seventh control valve 21, the eighth control valve 23, the ninth control valve 24, the tenth control valve 26, the eleventh control valve 27, and the twelfth control valve 29 are all closed;

[0106] In the Brayton reverse cycle subsystem, the thirteenth control valve 31, the fourteenth control valve 33, the fifteenth control valve 34, the sixteenth control valve 36, the seventeenth control valve 37, the eighteenth control valve 39, the nineteenth control valve 40, and the twentieth control valve 42 are all closed;

[0107] In the Stirling cycle subsystem, the twenty-first control valve 44, the twenty-second control valve 46, the twenty-third control valve 47, and the twenty-fourth control valve 49 are all closed. The high-temperature heat storage medium enters the heating surface of the Stirling engine 55 through the twenty-fifth control valve 51, and then returns to the high-temperature heat storage tank 45 through the twenty-sixth control valve 52. The low-temperature cold storage medium enters the cold surface of the Stirling engine 55 through the twenty-seventh control valve 53, and then returns to the low-temperature cold storage tank 48 through the twenty-eighth control valve 54. The Stirling generator 55 converts the stored thermal energy and cold energy into electrical energy under the drive of the temperature difference.

[0108] The stored thermal energy is converted into electrical energy output through the Stirling generator 55.

[0109] When there is an excess of grid electrical energy, the proposed multi-cycle cascaded large-temperature-span Carnot battery system operates in an energy storage mode to consume the excess power. When the grid power is insufficient, the proposed multi-cycle cascaded large-temperature-span Carnot battery system operates in a power release mode to support the grid.

[0110] Compared with the prior art, the present invention innovatively conducts multi-stage thermodynamic coupling of the absorption cycle, vapor compression cycle, Brayton reverse cycle, and Stirling cycle to construct a large-temperature-span Carnot battery system, successfully solving the core bottleneck problems of traditional energy storage such as energy grade regulation, narrow heat / cold storage temperature difference range, and low system round-trip efficiency, and having the following effects:

[0111] 1. Utilize the high-temperature tolerance characteristics of the gas working medium in the Brayton reverse cycle to change the upper limit of the heat storage temperature from the physical property constraints of traditional media to the mechanical strength limit of the container material, significantly broadening the application scenarios of high-temperature heat storage;

[0112] 2. Through the deep refrigeration coordination of the vapor compression cycle and the Brayton reverse cycle, achieve continuous temperature range coverage from cryogenic to ultra-high temperature, solving the industry problem of limited heat / cold storage temperature difference in a single-cycle system;

[0113] 3. Based on the thermal-electric coupling characteristics of the multi-cycle architecture, achieve the space-time decoupling and on-demand conversion of electrical energy, industrial waste heat, and terminal cold / heat loads. While improving the energy conversion efficiency, effectively balance the peak and valley loads of the grid through the flexible switching of the energy storage / discharge modes.

[0114] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent replacements or changes, and should be covered within the protection scope of the present invention.

Claims

1. A large-temperature cross-Carnot battery system based on multi-cycle cascading, characterized in that Comprising: An absorption subsystem that realizes waste heat absorption and release through solution circulation and is coupled with a medium-temperature heat / cold storage unit to regulate medium-temperature energy storage; A vapor compression cycle subsystem that realizes a low-temperature refrigeration cycle through a multi-stage compression-expansion process of an organic working fluid to form low-temperature cold energy storage; The Brayton reverse cycle subsystem that breaks through the temperature limit of the heat storage medium through the reverse cycle compression and expansion of a gas working fluid and converts energy into high-temperature heat energy storage; The Stirling cycle subsystem that directly converts the stored high-temperature heat energy and low-temperature cold energy into electrical energy output through a temperature difference driving mechanism.

2. The large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 1, characterized in that: The absorption subsystem includes a generator, a condenser, a first throttle valve, an evaporator, an absorber, a solution pump, a regenerator, a first circulation pump, a high-temperature buffer tank, a second circulation pump, a low-temperature buffer tank, a first control valve, a second control valve, a third control valve, a fourth control valve, and a third circulation pump; The refrigerant-side outlet of the generator is connected to the refrigerant-side inlet of the condenser, and the concentrated absorbent-side outlet is connected to the concentrated absorbent-side inlet of the regenerator; The refrigerant-side outlet of the condenser is connected to the inlet of the first throttle valve, and the outlet of the first throttle valve is connected to the refrigerant-side inlet of the evaporator; The refrigerant-side outlet of the evaporator is connected to the refrigerant-side inlet of the absorber. The concentrated absorbent-side inlet of the absorber is connected to the concentrated absorbent-side outlet of the regenerator. The dilute solution-side outlet is connected to the dilute absorbent-side inlet of the regenerator through a solution pump, and the dilute absorbent-side outlet of the regenerator is connected to the dilute absorbent-side inlet of the generator; The heat transfer oil-side outlet of the condenser is connected to the inlet of the high-temperature buffer tank through a first circulation pump, and the outlet of the high-temperature buffer tank forms a closed loop with the heat transfer oil-side inlet of the condenser; The heat transfer oil-side outlet of the evaporator is connected to the inlet of the low-temperature buffer tank, and the outlet of the low-temperature buffer tank forms a closed loop with the heat transfer oil-side inlet of the evaporator through a second circulation pump.

3. The large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 2, wherein: The energy storage medium outlet of the high-temperature buffer tank is connected to the inlet of the third circulation pump through a first control valve, and the outlet of the third circulation pump is connected to the energy storage medium-side inlet of the first heat exchanger; The energy storage medium-side outlet of the first heat exchanger is respectively connected to the energy storage medium inlet of the high-temperature buffer tank and the energy storage medium inlet of the low-temperature buffer tank through a second control valve and a fourth control valve; The outlet of the third control valve is connected in parallel to the inlet of the third circulation pump for regulating the distribution path of the energy storage medium between the high-temperature buffer tank and the low-temperature buffer tank; The energy storage medium of the absorption subsystem exchanges heat with the vapor compression cycle subsystem or the Brayton reverse cycle subsystem through a first heat exchanger to realize the storage and release of heat energy in the medium-temperature section.

4. The large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 3, characterized in that: The vapor compression cycle subsystem includes a first heat exchanger, a fifth control valve, a second throttle valve, a sixth control valve, a seventh control valve, a first compressor, an eighth control valve, a ninth control valve, a third throttle valve, a tenth control valve, an eleventh control valve, a second compressor, a twelfth control valve, and a second heat exchanger; The organic working fluid-side outlet / inlet of the first heat exchanger is respectively connected to the inlet of the fifth control valve and the outlet of the seventh control valve; The outlet of the fifth control valve is connected to the inlet of the second throttle valve, and the outlet of the second throttle valve is connected to the inlet of the sixth control valve; The inlet of the seventh control valve is connected to the outlet of the first compressor, and the inlet of the first compressor is connected to the outlet of the eighth control valve; The outlet of the sixth control valve and the inlet of the eighth control valve are jointly connected to the organic working fluid side inlet / outlet of the second heat exchanger; The organic working fluid side outlet / inlet of the second heat exchanger is respectively connected to the outlet of the tenth control valve and the inlet of the twelfth control valve; The inlet of the tenth control valve is connected to the outlet of the third throttle valve, and the inlet of the third throttle valve is connected to the outlet of the ninth control valve; The outlet of the twelfth control valve is connected to the inlet of the second compressor, and the outlet of the second compressor is connected to the inlet of the eleventh control valve; The inlet of the ninth control valve and the outlet of the eleventh control valve are jointly connected to the organic working fluid side inlet / outlet of the first heat exchanger to form a closed-loop working fluid circulation loop.

5. A large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 4, characterized in that: The Brayton reverse cycle subsystem includes a thirteenth control valve, a first expander, a fourteenth control valve, a fifteenth control valve, a third compressor, a sixteenth control valve, a seventeenth control valve, a second expander, an eighteenth control valve, a nineteenth control valve, a fourth compressor, a twentieth control valve, and a third heat exchanger; The gas side outlet / inlet of the second heat exchanger is respectively connected to the inlet of the thirteenth control valve and the outlet of the fifteenth control valve. The outlet of the thirteenth control valve is connected to the inlet of the first expander, the outlet of the first expander is connected to the inlet of the fourteenth control valve, the inlet of the fifteenth control valve is connected to the outlet of the third compressor, the inlet of the third compressor is connected to the outlet of the sixteenth control valve, the outlet of the fourteenth control valve and the inlet of the sixteenth control valve are respectively connected to the gas side inlet / outlet of the third heat exchanger, the organic working fluid side outlet / inlet of the third heat exchanger is respectively connected to the outlet of the eighteenth control valve and the inlet of the twentieth control valve, the inlet of the eighteenth control valve is connected to the outlet of the second expander, the inlet of the second expander is connected to the outlet of the seventeenth control valve, the outlet of the twentieth control valve is connected to the inlet of the fourth compressor, the outlet of the fourth compressor is connected to the inlet of the nineteenth control valve, and the inlet of the seventeenth control valve and the outlet of the nineteenth control valve are respectively connected to the gas side inlet / outlet of the second heat exchanger.

6. The large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 5, characterized in that: The Stirling cycle subsystem includes a twenty-first control valve, a high-temperature heat storage tank, a twenty-second control valve, a twenty-third control valve, a low-temperature cold storage tank, a twenty-fourth control valve, a fourth circulation pump, a twenty-fifth control valve, a twenty-sixth control valve, a twenty-seventh control valve, a twenty-eighth control valve, and a Stirling generator; The outlet of the heat transfer oil side of the third heat exchanger is connected to the inlets of the twenty-first control valve and the twenty-third control valve. The outlet of the twenty-first control valve is connected to the heat transfer oil inlet of the high-temperature heat storage tank. The outlet of the heat transfer oil of the high-temperature heat storage tank is connected to the inlet of the twenty-second control valve. The outlet of the twenty-third control valve is connected to the heat transfer oil inlet of the low-temperature cold storage tank. The outlet of the heat transfer oil of the low-temperature cold storage tank is connected to the inlet of the twenty-fourth control valve. The outlets of the twenty-second control valve and the twenty-fourth control valve are connected to the inlet of the fourth circulation pump. The outlet of the fourth circulation pump is connected to the heat transfer oil side inlet of the third heat exchanger. The heat storage medium outlet of the high-temperature heat storage tank is connected to the inlet of the twenty-fifth control valve. The outlet of the twenty-fifth control valve is connected to the heated side inlet of the Stirling generator. The outlet of the heated side of the Stirling generator is connected to the inlet of the twenty-sixth control valve. The outlet of the twenty-sixth control valve is connected to the heat storage medium inlet of the high-temperature heat storage tank. The cold storage medium outlet of the low-temperature cold storage tank is connected to the inlet of the twenty-seventh control valve. The outlet of the twenty-seventh control valve is connected to the cooled side inlet of the Stirling generator. The outlet of the cooled side of the Stirling generator is connected to the inlet of the twenty-eighth control valve. The outlet of the twenty-eighth control valve is connected to the cold storage medium inlet of the low-temperature cold storage tank.

7. A large-temperature cross-Carnot battery system based on multi-cycle cascade according to claim 6, characterized in that: The Brayton reverse cycle subsystem can flexibly adjust its operating mode by adjusting the opening and closing of the control valves, convert the heat or cold in the high-temperature buffer tank and the low-temperature buffer tank into high-temperature heat energy or low-temperature cold energy for storage, and the proportion can be flexibly adjusted.

8. A method for operating a large-temperature cross-Carnot battery system based on multi-cycle cascade, which is applied to a large-temperature cross-Carnot battery system according to any one of claims 1-7, and is characterized in that: Including: Heat storage mode: In the vapor compression cycle subsystem, the fifth control valve, the sixth control valve, the eleventh control valve, and the twelfth control valve are closed. In the Brayton reverse cycle subsystem, the thirteenth control valve, the fourteenth control valve, the nineteenth control valve, and the twentieth control valve are closed. The Stirling generator stops operating; The heat storage process is as follows: The heat storage medium enters the third circulation pump from the high-temperature buffer tank via the first control valve, then enters the first heat exchanger, and after flowing out of the first heat exchanger, it returns to the high-temperature buffer tank via the second control valve, and so on in a cycle; After the organic working fluid exchanges heat with the heat storage medium in the first heat exchanger, it enters the first compressor via the seventh control valve. The superheated steam flowing out of the first compressor enters the second heat exchanger via the eighth control valve to release heat and become liquid. The liquid working fluid enters the third throttle valve via the tenth control valve to reduce the temperature and pressure, and then enters the first heat exchanger via the ninth control valve, and so on in a cycle; After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger, it enters the third compressor via the fifteenth control valve. The high-temperature and high-pressure gas working fluid flowing out of the third compressor enters the third heat exchanger via the sixteenth control valve to release heat. The low-temperature and high-pressure gas working fluid enters the second expander via the eighteenth control valve to reduce the temperature and pressure, and then enters the second heat exchanger via the seventeenth control valve, and so on in a cycle; After the heat transfer oil absorbs heat in the third heat exchanger, it enters the high-temperature heat storage tank via the twenty-first control valve to heat the heat storage medium, then enters the fourth circulation pump via the twenty-second control valve, and then returns to the third heat exchanger, and so on in a cycle; Electric energy is consumed by the first compressor and the third compressor and converted into high-temperature heat energy stored in the high-temperature heat storage tank; Cold storage mode: In the vapor compression cycle subsystem, the seventh control valve, the eighth control valve, the ninth control valve, and the tenth control valve are closed. In the Brayton reverse cycle subsystem, the fifteenth control valve, the sixteenth control valve, the seventeenth control valve, and the eighteenth control valve are closed. The Stirling generator stops operating; The cold storage process is as follows: The cold storage medium enters the third circulation pump from the low-temperature buffer tank via the third control valve, then enters the first heat exchanger, and after flowing out of the first heat exchanger, it returns to the low-temperature buffer tank via the fourth control valve, and this cycle repeats; After the organic working fluid exchanges heat with the cold storage medium in the first heat exchanger, it enters the second throttle valve via the fifth control valve. The low-temperature and low-pressure working fluid flowing out of the second throttle valve enters the second heat exchanger via the sixth control valve to absorb heat and become gaseous. The gaseous working fluid enters the second compressor via the twelfth control valve to increase in temperature and pressure, and then enters the first heat exchanger via the eleventh control valve, and this cycle repeats; After the gas working fluid exchanges heat with the organic working fluid in the second heat exchanger, it enters the first expander via the thirteenth control valve. The low-temperature and low-pressure gas working fluid flowing out of the first expander enters the third heat exchanger via the fourteenth control valve to absorb heat. The high-temperature and low-pressure gas working fluid enters the fourth compressor via the twentieth control valve to increase in temperature and pressure, and then enters the second heat exchanger via the nineteenth control valve, and this cycle repeats; After the heat-conducting oil exchanges heat in the third heat exchanger, it enters the low-temperature cold storage tank via the twenty-third control valve to heat the cold storage medium, and then enters the fourth circulation pump via the twenty-fourth control valve, and then returns to the third heat exchanger, and this cycle repeats; Electric energy is consumed by the second compressor and the fourth compressor, and is converted into high-temperature heat energy and stored in the high-temperature heat storage tank.

9. The operating method of a large-temperature transcritical Carnot battery system based on multi-cycle cascading according to claim 8, characterized in that: It also includes an energy release strategy: In the absorption subsystem, the first control valve, the second control valve, the third control valve, and the fourth control valve are all closed; In the vapor compression refrigeration cycle subsystem, the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, the ninth control valve, the tenth control valve, the eleventh control valve, and the twelfth control valve are all closed; In the Brayton reverse cycle subsystem, the thirteenth control valve, the fourteenth control valve, the fifteenth control valve, the sixteenth control valve, the seventeenth control valve, the eighteenth control valve, the nineteenth control valve, and the twentieth control valve are all closed; In the Stirling cycle subsystem, the twenty-first control valve, the twenty-second control valve, the twenty-third control valve, and the twenty-fourth control valve are all closed. The high-temperature heat storage medium enters the heating surface of the Stirling engine via the twenty-fifth control valve, and then returns to the high-temperature heat storage tank via the twenty-sixth control valve. The low-temperature cold storage medium enters the cooling surface of the Stirling engine via the twenty-seventh control valve, and then returns to the low-temperature cold storage tank via the twenty-eighth control valve. The Stirling generator converts the stored heat energy and cold energy into electric energy output under the drive of the temperature difference.

10. The operation method of a large temperature-span Carnot battery system based on multi-cycle cascade according to claim 9, characterized in that: For the demand scenario of power consumption and waste heat storage in the cooling season, an energy storage strategy is adopted to supplement the heat exchanger of the low-temperature buffer tank to supply cooling to users; For the demand scenario of power grid peak shaving in the cooling season, an energy release strategy is adopted to supplement the heat exchanger of the low-temperature cold storage tank to supply cooling to users; For the demand scenario of power consumption during the heating season, an energy storage strategy is adopted to flexibly regulate the heat output of industrial waste heat and high-temperature buffer tanks for heating users. For the demand scenario of power grid peak shaving during the heating season, an energy release strategy is adopted to flexibly regulate the heat output of industrial waste heat and high-temperature heat storage tanks for heating users.

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