Energy storage system and power generation and energy storage integrated system

Abstract

The utility model relates to an energy storage system and a power generation and energy storage integrated system, the energy storage system comprises a motor, a generator, a flywheel energy storage unit and a carbon dioxide energy storage unit, and the flywheel energy storage unit is connected between the motor and the generator; the carbon dioxide energy storage unit comprises a compressor, a turbine, a carbon dioxide circulating energy storage device and a heat exchange device, and the carbon dioxide energy storage device comprises a liquid storage tank, a gas storage tank, a first flow path communicating between an outlet of the compressor and an inlet of the turbine and a second flow path communicating between an outlet of the turbine and an inlet of the compressor; the liquid storage tank is arranged on the first flow path, the gas storage tank is arranged on the second flow path, the heat exchange device comprises a first heat exchanger, the heat exchange device cools carbon dioxide flowing from an outlet of the compressor to the liquid storage tank through the first heat exchanger, and the energy storage system can provide a better energy supply effect according to the requirements of a power grid.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power grid energy storage, and in particular, to an energy storage system and a power generation and energy storage integrated system. Background Art

[0002] In the related art, an energy storage system is used to store the energy of a power generation system and supply it to the power grid when needed. However, the demands of the power grid are becoming increasingly complex, and the existing energy storage systems cannot better meet the complex demands of the power grid, and the energy supply effect is relatively unsatisfactory. Summary of the Utility Model

[0003] The purpose of the present disclosure is to provide an energy storage system and a power generation and energy storage integrated system to provide a better energy supply effect according to the demands of the power grid, so as to at least partially solve the above technical problems.

[0004] To achieve the above purpose, in the first aspect of the present disclosure, an energy storage system is provided, including: a motor for electrically connecting to a power generation system; a generator for electrically connecting to the power grid; a flywheel energy storage unit connected between the motor and the generator; and a carbon dioxide energy storage unit including a compressor, a turbine, a carbon dioxide circulation energy storage device, and a heat exchange device. The carbon dioxide circulation energy storage device includes a liquid storage tank, a gas storage tank, a first flow path connecting the outlet of the compressor and the inlet of the turbine, and a second flow path connecting the outlet of the turbine and the inlet of the compressor. The liquid storage tank is arranged on the first flow path for storing liquid carbon dioxide, and the gas storage tank is arranged on the second flow path for storing gaseous carbon dioxide. The heat exchange device includes a first heat exchanger, and the heat exchange device cools the carbon dioxide flowing from the outlet of the compressor to the liquid storage tank through the first heat exchanger.

[0005] Optionally, the heat exchange device further includes a cold storage tank, a heat storage tank, and a third flow path connecting the outlet of the cold storage tank and the inlet of the heat storage tank. The first heat exchange flow path of the first heat exchanger is connected to the first flow path and is located between the compressor and the liquid storage tank in the first flow path. The second heat exchange flow path of the first heat exchanger is connected to the third flow path.

[0006] Optionally, the heat exchange device further includes a second heat exchanger, and the heat exchange device heats the carbon dioxide flowing from the outlet of the turbine to the gas storage tank through the second heat exchanger.

[0007] Optionally, the heat exchange device further includes a fourth flow path that is connected between the outlet of the heat storage tank and the inlet of the cold storage tank. The third heat exchange flow path of the second heat exchanger is connected in the fourth flow path, and the fourth heat exchange flow path of the second heat exchanger is connected in the second flow path and is located between the gas storage tank and the turbine in the second flow path.

[0008] Optionally, the number of the liquid storage tanks is plural, and the plural liquid storage tanks are arranged in parallel in the first flow path.

[0009] Optionally, the first heat exchanger is configured as a cooler for cooling the carbon dioxide flowing from the outlet of the compressor to the liquid storage tank, and the second heat exchanger is configured as a heater for heating the carbon dioxide flowing from the outlet of the turbine to the gas storage tank.

[0010] Optionally, the energy storage system further includes a monitoring mechanism, and the monitoring mechanism is electrically connected to the motor, the generator, the flywheel energy storage unit, and the carbon dioxide energy storage unit respectively.

[0011] Optionally, the monitoring mechanism is configured as a visualization large screen.

[0012] In a second aspect of the present disclosure, a power generation and energy storage integrated system is provided, including the energy storage system and the power generation system of the above optional solutions.

[0013] Optionally, the power generation system includes at least one of a photovoltaic power generation system, a wind power generation system, and a hydropower generation system.

[0014] Through the above technical solution, that is, the energy storage system provided by the present disclosure, when storing energy through this energy storage system, the energy received by the motor from the power generation system can be stored simultaneously by the flywheel energy storage unit and the carbon dioxide energy storage unit. Among them, the carbon dioxide energy storage unit has the ability to store energy on a large scale for a long time, and the flywheel energy storage has the ability of rapid response. The combination of the two can achieve efficient storage and utilization of energy, and can provide better functional effects according to the complex requirements of the power grid. For example, when the power supply demand of the power grid is low, the generator can be powered only by the flywheel energy storage unit and used for power generation of the power grid. When the power supply demand of the power grid is high, the carbon dioxide energy storage unit can be started again. Or, when the power grid load is at a peak or rapid adjustment is required, the flywheel energy storage unit can be used for rapid response first, releasing the stored mechanical energy and converting it into electrical energy output. As the power grid load continues to increase, the carbon dioxide energy storage unit is started again to supplement the power demand of the power grid. In addition, the flywheel energy storage unit and the carbon dioxide energy storage unit can be started successively or simultaneously, and can be specifically set according to the requirements of the power grid. The present disclosure is not limited thereto. Specifically, carbon dioxide can circulate inside the first flow path and the second flow path. When gaseous carbon dioxide flows out of the gas storage tank and flows along the second flow path into the compressor, the gaseous carbon dioxide will be compressed by the compressor. The compressed carbon dioxide will be discharged from the outlet of the compressor and enter the first flow path. After flowing through the first heat exchanger on the first flow path, under the further cooling of the first heat exchanger, the carbon dioxide will be further cooled into a liquid state and can enter the liquid storage tank for temporary storage. This is the energy storage step. When the power grid needs to utilize the energy of this part of carbon dioxide, the carbon dioxide in the liquid storage tank will be discharged from the outlet of the liquid storage tank and enter the turbine through the first flow path. The turbine can release the energy stored in the liquid carbon dioxide through its own heater. The liquid carbon dioxide heats up and expands, and the internal energy released by the expansion can be converted into electrical energy for supplying the generator to generate electricity through the turbine. The generator supplies the energy to the power grid, and the carbon dioxide becomes gaseous at this time and continues to return to the gas storage tank from the outlet of the turbine. In addition, the energy stored previously in the flywheel energy storage unit can also be used to supply power to the generator, and thus the power grid can be powered simultaneously or successively by the flywheel energy storage unit and the carbon dioxide energy storage unit.

[0015] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0017] Figure 1It is a schematic structural diagram of an energy storage system and a power generation and energy storage integrated system provided in an exemplary embodiment of the present disclosure.

[0018] Description of Reference Numerals

[0019] 1 - Motor; 2 - Generator; 3 - Flywheel energy storage unit; 4 - Carbon dioxide energy storage unit; 410 - Compressor; 420 - Turbine; 430 - Carbon dioxide circulation energy storage device; 431 - Liquid storage tank; 432 - Gas storage tank; 433 - First flow path; 434 - Second flow path; 440 - Heat exchange device; 441 - First heat exchanger; 442 - Second heat exchanger; 443 - Cold storage tank; 444 - Heat storage tank; 445 - Third flow path; 446 - Fourth flow path; 5 - Power generation system; 6 - Power grid; 7 - Monitoring mechanism. Detailed Embodiments

[0020] The following describes in detail the specific embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present disclosure, and are not intended to limit the present disclosure.

[0021] In the present disclosure, unless otherwise stated, the orientation terms such as "inner" and "outer" refer to the inner and outer of the contour of the component or structure itself; "first", "second", etc. are used to distinguish one element from another, and do not have sequentiality and importance.

[0022] In the first aspect of the present disclosure, an energy storage system is provided. Referring to Figure 1 as shown, the energy storage system includes a motor 1, a generator 2, a flywheel energy storage unit 3, and a carbon dioxide energy storage unit 4. Among them, the motor 1 is used for electrically connecting to a power generation system 5; the generator 2 is used for electrically connecting to a power grid 6, and the flywheel energy storage unit 3 is connected between the motor 1 and the generator 2; the carbon dioxide energy storage unit 4 includes a compressor 410, a turbine 420, a carbon dioxide circulation energy storage device 430, and a heat exchange device 440. The carbon dioxide circulation energy storage device 430 includes a liquid storage tank 431, a gas storage tank 432, a first flow path 433 connected between the outlet of the compressor 410 and the inlet of the turbine 420, and a second flow path 434 connected between the outlet of the turbine 420 and the inlet of the compressor 410. The liquid storage tank 431 is disposed on the first flow path 433 for storing liquid carbon dioxide, and the gas storage tank 432 is disposed on the second flow path 434 for storing gaseous carbon dioxide. The heat exchange device 440 includes a first heat exchanger 441, and the heat exchange device 440 cools the carbon dioxide flowing from the outlet of the compressor 410 to the liquid storage tank 431 through the first heat exchanger 441.

[0023] In the above manner, that is, the energy storage system provided by the present disclosure, when storing energy through this energy storage system, the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 can simultaneously store the energy received by the motor 1 from the power generation system 5. Among them, the carbon dioxide energy storage unit 4 has the ability to store energy on a large scale and for a long time, and the flywheel energy storage unit 3 has the ability of rapid response. The combination of the two can achieve efficient storage and utilization of energy, and can provide better functional effects according to the complex requirements of the power grid. For example, when the power supply demand of the power grid is low, only the flywheel energy storage unit 3 can supply energy to the generator and be used for the power grid 6 to generate electricity. When the power supply demand of the power grid 6 is high, the carbon dioxide energy storage unit 4 can be started again. First, the flywheel energy storage unit 3 can be used for rapid response, releasing the stored mechanical energy and converting it into electrical energy output. As the load of the power grid 6 continues to increase, the carbon dioxide energy storage unit 4 is started again to supplement the power demand of the power grid 6. In addition, the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 can be started successively or simultaneously, and can be specifically set according to the requirements of the power grid 6. The present disclosure is not limited thereto. Specifically, carbon dioxide can circulate inside the first flow path 433 and the second flow path 434. When gaseous carbon dioxide flows out of the gas storage tank 432 and flows along the second flow path 434 into the compressor 410, the gaseous carbon dioxide will be compressed by the compressor 410. The compressed carbon dioxide will be discharged from the outlet of the compressor 410 and enter the first flow path 433. After flowing through the first heat exchanger 441 on the first flow path 433, under the further cooling of the first heat exchanger 441, the carbon dioxide will be further cooled into a liquid state and can enter the liquid storage tank 431 for temporary storage. This is the energy storage step. When the power grid 6 needs to utilize the energy of this part of carbon dioxide, the carbon dioxide in the liquid storage tank 431 will be discharged from the outlet of the liquid storage tank 431 and enter the turbine 420 through the first flow path 433. The turbine 420 can release the energy stored in the liquid carbon dioxide. The liquid carbon dioxide will heat up and expand after releasing energy, and the internal energy released by the expansion can be converted into electrical energy for supplying the generator 2 to generate electricity through the turbine 420. The generator 2 supplies the energy to the power grid 6. At this time, the carbon dioxide becomes gaseous and continues to return to the gas storage tank 432 from the outlet of the turbine 420. At the same time, the energy stored in the flywheel energy storage unit 3 previously can also be used to supply power to the generator 2 at this time, so as to be able to supply power to the power grid 6 through the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 at the same time. And through the above power supply method, carbon dioxide can be compressed by the compressor 410 and cooled into a liquid state by the first heat exchanger 441, and then the liquid carbon dioxide can be stored through the liquid storage tank 431. When the power generation demand of the power grid is large, the liquid carbon dioxide can be used to release energy through the turbine 420 to meet the power generation demand of the power grid.

[0024] It should be noted that the above flywheel energy storage unit 3 and carbon dioxide energy storage unit 4 can store energy and discharge energy for power supply separately or jointly according to the actual power supply demand of the power grid 6. For example, during the energy storage charging process, the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 can jointly store energy. When the power supply demand of the power grid is low, only the flywheel energy storage unit 3 can supply energy to the generator 2 and be used for power generation of the power grid 6. When the power supply demand of the power grid is high, the carbon dioxide energy storage unit 4 can be started again to convert the liquid carbon dioxide into gas and release the energy into the generator 2 for power generation of the generator, so that the power supply demand of the power grid can be met in time when the power supply demand of the power grid is high, so as to achieve the optimal distribution of energy and the stable operation of the power grid.

[0025] In addition, the flywheel energy storage unit 3 mentioned in the above embodiments can adopt the flywheel energy storage method widely existing in the prior art. For example, during energy storage, the flywheel in the flywheel energy storage unit 3 can be driven to rotate by the motor 1, and the flywheel stores the energy in the form of kinetic energy to complete the energy storage process of converting electrical energy into mechanical energy. The energy is stored in the high-speed rotating flywheel body. After that, the motor 1 can drive the flywheel to maintain a constant speed until it receives the control signal for energy release, and then energy release can be carried out. During the energy release process of the flywheel, the high-speed rotating flywheel can drive the generator 2 to generate electricity, and a suitable current and voltage can be output through equipment such as a power converter to complete the energy release process of converting mechanical energy into electrical energy. During the conversion process, the speed of the flywheel will continuously decrease, and then the energy can be gradually released and completed.

[0026] In some embodiments, referring to Figure 1 As shown, the heat exchange device 440 includes a cold storage tank 443, a heat storage tank 444, and a third flow path 445 connected between the outlet of the cold storage tank 443 and the inlet of the heat storage tank 444. The first heat exchange flow path of the first heat exchanger 441 (not shown in the figure, which is the internal flow path of the first heat exchanger 441) is connected to the first flow path 433 and is located between the compressor 410 and the liquid storage tank 431 in the first flow path 433. The second heat exchange flow path of the first heat exchanger 441 (not shown in the figure, which is the internal flow path of the first heat exchanger 441) is connected to the third flow path 445. In this way, the heat exchange process of carbon dioxide after being compressed by the compressor 410 can be realized through the cold storage tank 443, the heat storage tank 444, and the third flow path 445, that is, it can be referred to Figure 1As shown, after being compressed by the compressor 410, the carbon dioxide will continue to move along the first flow path 433. When the carbon dioxide enters the first heat exchange flow path inside the first heat exchanger 441, the cold medium (such as water) flowing out from the outlet of the cold storage tank 443 will also flow along the third flow path 445 into the second heat exchange flow path inside the first heat exchanger 441. The compressed carbon dioxide in the first heat exchange flow path will generate a large amount of internal energy. The internal energy generated by the carbon dioxide in the first heat exchanger 441 will be used to heat the cold medium in the second heat exchange flow path, thereby reducing the temperature of the carbon dioxide to liquefy the carbon dioxide faster to complete the heat exchange process. After being heated, the cold medium will heat up and become a hot medium. The hot medium continues to flow along the third flow path 445 with the stored internal energy, and then the hot medium can be sent to the heat storage tank 444 for storage to achieve the effect of storing internal energy.

[0027] In some embodiments, reference Figure 1 As shown, the heat exchange device 440 further includes a second heat exchanger 442 , and the heat exchange device 440 heats the carbon dioxide flowing from the outlet of the turbine 420 to the gas storage tank 432 through the second heat exchanger 442 . In this way, the second heat exchanger 442 can be used to receive the heated carbon dioxide from the turbine 420 after energy release, and the carbon dioxide can be further heated before being sent to the gas tank 432 for the next circulation of the carbon dioxide. Under the heating action of the second heat exchanger 442, the carbon dioxide flowing out of the outlet of the turbine 420 can be heated by the second heat exchanger 442 before entering the gas tank 432, so that this part of the carbon dioxide can be kept as consistent as possible with the carbon dioxide in the gas tank 432 or with a smaller temperature difference, thereby ensuring that the pressures of the two batches of carbon dioxide can be kept as consistent as possible, and preventing multiple batches of carbon dioxide with different temperatures and pressures from mixing into the gas tank 432, so as to reduce or even avoid the situation where the pressure inside the gas tank 432 is too low and deflated, or the internal pressure is too high and the cylinder explodes, thereby improving the safety of the energy storage device during the energy storage and release process.

[0028] In some embodiments, reference Figure 1As shown, the heat exchange device 440 further includes a fourth flow path 446. The fourth flow path 446 is connected between the outlet of the heat storage tank 444 and the inlet of the cold storage tank 443. The third heat exchange flow path of the second heat exchanger 442 (not shown in the figure, which is the internal flow path of the second heat exchanger 442) is connected in the fourth flow path 446, and the fourth heat exchange flow path of the second heat exchanger 442 (not shown in the figure, which is the internal flow path of the second heat exchanger 442) is connected in the second flow path 434 and is located between the gas storage tank 432 and the turbine 420 in the second flow path 434. In this way, through the cold storage tank 443, the heat storage tank 444 and the fourth flow path 446, the heat exchange process of carbon dioxide after energy release by the turbine 420 can be realized, that is, similar to the heat exchange process after compression by the compressor 410 mentioned in the above embodiment, but the heat exchange method in this process is opposite to the heat exchange method after compression by the compressor 410 mentioned above, that is, reference can be made to Figure 1 As shown, after the carbon dioxide releases energy through the turbine 420, it will continue to move forward along the second flow path 434. When the carbon dioxide enters the fourth heat exchange flow path inside the second heat exchanger 442, the hot medium (such as water) flowing out from the outlet of the heat storage tank 444 will also flow into the third heat exchange flow path inside the second heat exchanger 442 along the fourth flow path 446. The carbon dioxide in the fourth heat exchange flow path will exchange heat with the hot medium in the third heat exchange flow path, that is, the hot medium will supply the previously stored internal energy to the carbon dioxide again to heat up the carbon dioxide, and after the heat exchange is completed, the hot medium will cool down to become a cold medium. The cold medium can continue to flow along the fourth flow path 446 and then enter the cold storage tank 443 again for storage, so as to continue to absorb the internal energy of the compressed carbon dioxide subsequently.

[0029] In some embodiments, reference is made to Figure 1 As shown, the number of the liquid storage tanks 431 is multiple, and the multiple liquid storage tanks 431 are arranged in parallel in the first flow path 433. In this way, the multiple liquid storage tanks 431 can be jointly used to store compressed and liquefied carbon dioxide, and thus the storage capacity of carbon dioxide can be improved. When the power supply demand of the power grid 6 is relatively high, multiple liquid storage tanks 431 can simultaneously supply multiple portions of carbon dioxide to the turbine 420 for power generation, and the power supply efficiency can be improved to meet the power generation demand of the power grid, that is, reference can be made to Figure 1 As shown, after the carbon dioxide is compressed and cooled by the compressor 410 and the first heat exchanger 441, it can enter the liquid storage tank 431 through the inlet of the multiple liquid storage tanks 431 for storage. When it is necessary to use this part of carbon dioxide to supply energy for power generation to the power grid 6, the carbon dioxide can be discharged from the outlets of the multiple liquid storage tanks 431 to the turbine 420 for energy supply.

[0030] It should be noted that the number of the liquid storage tanks 431 can be any suitable number more than two. The three liquid storage tanks 431 shown in the accompanying drawings of the present disclosure are only for illustrative purposes. The liquid storage tanks 431 can also be two, four, five or more. The present disclosure does not make specific limitations thereto.

[0031] In some embodiments, referring to Figure 1 as shown, the first heat exchanger 441 is configured as a cooler, and the cooler is used to cool the carbon dioxide flowing from the outlet of the compressor 410 to the liquid storage tank 431. The second heat exchanger 442 is configured as a heater, and the heater is used to heat the carbon dioxide flowing from the outlet of the turbine 420 to the gas storage tank 432. In this way, the carbon dioxide compressed by the compressor 410 is cooled by the cooler, and has a better cooling effect on the carbon dioxide. The carbon dioxide after the energy release of the turbine 420 is heated by the heater, and has a better heating effect on the carbon dioxide. Through the combined action of the cooler and the heater, energy can be circulated and absorbed and released between the third flow path 445 and the fourth flow path 446. Moreover, the present disclosure does not make specific limitations on the specific types of the cooler and the heater, as long as they can cool and heat the carbon dioxide. For example, the cooler can be a plate cooler, a shell and tube cooler, a finned tube cooler or a double pipe cooler, etc. Among them, the first heat exchange flow path and the second heat exchange flow path in the first heat exchanger 441 can be arranged accordingly according to the specific structural form of the cooler, which is a known structure in the prior art and will not be elaborated herein. The heater can be a plate heater, a tube heater, a cylindrical heater, etc. The third heat exchange flow path and the fourth heat exchange flow path in the second heat exchanger 442 can be arranged accordingly according to the specific structural form of the heater, which is a known structure in the prior art and will not be elaborated herein.

[0032] In some embodiments, referring to Figure 1As shown, the energy storage system further includes a monitoring mechanism 7, which is electrically connected to the motor 1, the generator 2, the flywheel energy storage unit 3, and the carbon dioxide energy storage unit 4 respectively. In this way, the monitoring mechanism 7 can play a role in remotely monitoring the entire energy storage system, so as to monitor the working state of the energy storage system, and further ensure that the energy storage system can operate stably to continuously supply power to the power grid 6. For example, the monitoring mechanism 7 can monitor the motor speed and motor temperature of the motor 1; the temperature and power generation efficiency of the generator 2; the start / stop of the working state of the flywheel energy storage unit 3, the energy storage and release values of the flywheel, and the energy storage and release efficiency; the liquid carbon dioxide content inside the multiple liquid storage tanks 431 in the carbon dioxide energy storage unit 4, the internal pressure of the liquid storage tank 431, the energy storage and release efficiency of the carbon dioxide energy storage unit 4, and the size of the energy storage value. The above values can be monitored in cooperation with sensors and the monitoring mechanism 7. The monitoring mechanism 7 can adopt an existing conventional monitoring mechanism, and its purpose is to be able to display the states of various devices for the staff to use as a basis for operation and adjustment.

[0033] In some embodiments, referring to Figure 1 As shown, the monitoring mechanism 7 is configured as a visualization large screen. In this way, the monitoring mechanism 7 can adopt a monitoring method similar to digital twin to monitor the working states of various mechanisms in the energy storage system, that is, make full use of physical models, sensors, and the operation history data of each mechanism to integrate the functions of visual monitoring and early warning monitoring of multiple physical quantities, multiple scales, and multiple probabilities. Through the above method, the intelligence of the energy storage system can be improved. The visualization large screen is a relatively mature technology, and the present disclosure will not be specifically elaborated here.

[0034] In a second aspect of the present disclosure, a power generation and energy storage integrated system is provided. The power generation and energy storage integrated system includes the energy storage system and the power generation system 5 mentioned in the above specific embodiments. And the energy storage system has all the beneficial effects in the above embodiments.

[0035] The power generation system 5 mentioned in the above embodiments may include, for example, at least one of a photovoltaic power generation system, a wind power generation system, and a hydropower generation system. Through any one or more of the above power generation systems, power can be supplied to drive the motor 1 in the energy storage system, and then the motor 1 can drive the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 to perform energy storage operations.

[0036] The present disclosure exemplarily describes the energy storage and release process of the energy storage system, which may include the following steps:

[0037] The power generation system 5 starts power generation, driving the motor 1 to start working. The generator of the motor 1 can drive the flywheel in the flywheel energy storage unit 3 to start rotating and store mechanical energy, and can also drive the compressor 410 to start working at the same time. After the compressor 410 preliminarily compresses the carbon dioxide from the gas storage tank 432, it is discharged from the outlet of the compressor 410 along the first flow path 433 to the first heat exchanger 441. The first heat exchanger 441 liquefies the compressed carbon dioxide. After cooling the carbon dioxide passing through the first heat exchanger 441 with the cold medium in the cold storage tank 443, the internal energy of the compressed carbon dioxide is absorbed, and this part of the internal energy flows into the heat storage tank 444 through the third flow path 445 for storage. After the carbon dioxide is cooled, it enters the liquid storage tank 431 for storage. When the flywheel in the flywheel energy storage unit 3 reaches the preset speed, the energy storage process of this energy storage system can be completed.

[0038] When the power grid 6 needs this energy storage system to supply power, when the power supply demand is low, power can be supplied to the generator 2 only through the flywheel energy storage unit 3, and then the electric energy generated by the generator 2 is used to supply power to the power grid 6. When the power supply demand of the power grid 6 is high, power can be supplied to the generator 2 through the flywheel energy storage unit 3 and the carbon dioxide energy storage unit 4 at the same time. The carbon dioxide in multiple liquid storage tanks 431 is discharged from the outlet of the liquid storage tank 431 and continues to move forward along the first flow path 433. After the carbon dioxide enters the turbine 420, it expands by releasing energy through turbine power generation to supply power to the generator 2 to transmit the electric energy to the power grid 6. After the expanded carbon dioxide is discharged from the outlet of the turbine 420, it enters the second flow path 434 and passes through the second heat exchanger 442. At this time, the heat medium in the heat storage tank 444 also passes through the fourth flow path 446 into the second heat exchanger. By exchanging heat between the heat medium and the carbon dioxide, the temperature of the carbon dioxide is increased. After the temperature of the carbon dioxide rises, it enters the gas storage tank 432 for the next cycle. After the heat medium exchanges heat with the carbon dioxide and its temperature decreases, it continues to return to the cold storage tank 443 for storage for the next cycle.

[0039] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0040] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0041] In addition, any combination can be made among various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. An energy storage system, characterized in that, Comprising: A motor for electrically connecting to a power generation system; A generator for electrically connecting to a power grid; A flywheel energy storage unit connected between the motor and the generator; And A carbon dioxide energy storage unit, including a compressor, a turbine, a carbon dioxide circulating energy storage device, and a heat exchange device. The carbon dioxide circulating energy storage device includes a liquid storage tank, a gas storage tank, a first flow path connecting the outlet of the compressor and the inlet of the turbine, and a second flow path connecting the outlet of the turbine and the inlet of the compressor. The liquid storage tank is arranged on the first flow path for storing liquid carbon dioxide, and the gas storage tank is arranged on the second flow path for storing gaseous carbon dioxide. The heat exchange device includes a first heat exchanger, and the heat exchange device cools the carbon dioxide flowing from the outlet of the compressor to the liquid storage tank through the first heat exchanger.

2. The energy storage system according to claim 1, wherein The heat exchange device further includes a cold storage tank, a heat storage tank, and a third flow path connecting the outlet of the cold storage tank and the inlet of the heat storage tank. The first heat exchange flow path of the first heat exchanger is connected to the first flow path and is located between the compressor and the liquid storage tank in the first flow path. The second heat exchange flow path of the first heat exchanger is connected to the third flow path.

3. The energy storage system according to claim 2, wherein The heat exchange device further includes a second heat exchanger, and the heat exchange device heats the carbon dioxide flowing from the outlet of the turbine to the gas storage tank through the second heat exchanger.

4. The energy storage system according to claim 3, wherein The heat exchange device further includes a fourth flow path connecting the outlet of the heat storage tank and the inlet of the cold storage tank. The third heat exchange flow path of the second heat exchanger is connected to the fourth flow path, and the fourth heat exchange flow path of the second heat exchanger is connected to the second flow path and is located between the gas storage tank and the turbine in the second flow path.

5. The energy storage system according to claim 1, wherein The number of the liquid storage tanks is multiple, and the multiple liquid storage tanks are arranged in parallel in the first flow path.

6. The energy storage system according to claim 3, wherein The first heat exchanger is configured as a cooler for cooling the carbon dioxide flowing from the outlet of the compressor to the liquid storage tank, and the second heat exchanger is configured as a heater for heating the carbon dioxide flowing from the outlet of the turbine to the gas storage tank.

7. The energy storage system according to claim 1, wherein The energy storage system further includes a monitoring mechanism, and the monitoring mechanism is electrically connected to the motor, the generator, the flywheel energy storage unit, and the carbon dioxide energy storage unit respectively.

8. The energy storage system according to claim 7, characterized in that The monitoring mechanism is configured as a visualization large screen.

9. A power generation and energy storage integrated system, characterized in that, Including the energy storage system and the power generation system according to any one of claims 1-8.

10. The power generation and energy storage integrated system according to claim 9, wherein The power generation system includes at least one of a photovoltaic power generation system, a wind power generation system, and a hydraulic power generation system.

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