A constant-pressure energy storage device and a new energy power generation system

Abstract

The present disclosure provides a constant-pressure energy storage device, which includes a sub-control system and a plurality of energy storage working units connected thereto. The energy storage working unit includes a liquid storage tank, a hydraulic unit, an energy storage mechanism, and a pressure regulation mechanism that are sequentially connected through a pipeline provided with a valve. The energy storage mechanism and the pressure regulation mechanism respectively contain a working liquid and a dissolution liquid, and a working gas with a certain pressure is contained above the liquid level in the energy storage mechanism. The solubility of the working gas in the working liquid and the dissolution liquid is different. When the pressure of the working gas in the energy storage mechanism shows a continuous change trend, the dissolution amount of the working gas in the dissolution liquid is changed through the pressure regulation mechanism, and under the action of the hydraulic unit, the working liquid circulates between the energy storage mechanism and the liquid storage tank, so that the working gas in the energy storage mechanism is maintained at a set pressure to achieve energy storage and energy release. The present disclosure can realize energy storage and energy release in a long time, with a large capacity and in multiple ways by a compressed gas that maintains a constant pressure without heat exchange and heat storage.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of new energy power generation and energy storage, and particularly relates to a constant pressure energy storage device without heat storage and a new energy power generation system. Background Art

[0002] Both wind energy and solar energy are renewable energy sources. Since they come from nature, they will not be exhausted, and this characteristic makes wind power generation and photovoltaic power generation a good choice for sustainable power supply. Compared with fossil fuel power generation, wind power generation and photovoltaic power generation can significantly reduce the emissions of carbon dioxide and other greenhouse gases, helping to mitigate the impact of global warming. However, affected by natural and technological factors, wind power generation and photovoltaic power generation are characterized by intermittency, randomness, and poor dispatchability, which will cause a series of power quality problems. First of all, when wind power generation and photovoltaic power generation are affected by weather and the output power fluctuates, it will cause voltage fluctuations on the transmission line of the wind farm, and then cause grid voltage fluctuations; when the output power of the wind power generation system is large, flicker phenomena will also occur. Secondly, during the process of wind power generation and photovoltaic power generation, the output of their units is somewhat random. Therefore, as the proportion of the power generation of these two new energy sources in the total grid power generation continues to increase, there may be problems of frequency fluctuations in the power grid, and such power grid frequency problems will have an adverse impact on the power system and its users. In addition, since both wind power generation and photovoltaic power generation use a large number of power electronic devices, they will generate a large amount of harmonics and DC components. After the harmonics are injected into the power system, it will cause voltage distortion of the grid system, affecting the power quality of the entire grid system. When the proportion of these two new energy power generations in the power grid is small, the above defects can be controlled within the allowable range through modern power electronic technologies; when these two new energy power generations are connected to the grid on a large scale, it will have a great impact on the power system. The power grid must control the capacity of the new energy power generation connected to it within a controllable range to minimize the adverse effects, which not only greatly restricts the construction scale and development speed of these two new energy sources, but also leads to the fact that coal-fired power plants with greater environmental damage and higher carbon emissions still serve as the main power generation. To ensure the stable operation of the power grid, a part of the power generation capacity of these two new energy sources is often wasted in vain, making the new energy power generation system unable to obtain the expected economic benefits. For this reason, measures such as researching and promoting new energy storage technologies and supporting new energy storage power stations have been started to reduce energy waste, improve the utilization efficiency of new energy, and thus achieve energy conservation and environmental protection. Secondly, new energy storage technologies can improve the reliability and stability of energy. Due to the large capital investment in energy storage power stations using new energy storage technologies, they mainly play three roles at present: one is to balance power supply and demand. The energy storage power station can store electric energy during the peak power demand to balance power supply and ensure the stability of the power network, which helps to reduce the risk of power outages and improve the reliability of the power system; the second is to integrate renewable energy: Renewable energy sources such as wind energy and solar energy are volatile, and the energy storage power station can capture and store excess electric energy to provide power during unstable periods; the third is frequency modulation and standby power supply. The energy storage power station can be used as a frequency modulation device for the power system to quickly respond to power demand fluctuations.However, this cannot completely eliminate the above-mentioned adverse effects of these two new energy power generations on the power grid. For the stability of the entire power grid and relatively high power quality, new energy can only account for a small share in power supply. The traditional power generation method mainly based on coal-fired power generation is still the main means of power generation because the power generation process is fully controllable throughout and the power quality is excellent, which is contrary to the original intention of vigorously developing new energy.

[0003] Compressed gas energy storage is to use an electric motor to do work when there is surplus electric energy, use a compressor to compress the gas and increase the pressure, and convert the electric energy into pressure potential energy; when power generation is required, use the high-pressure gas to drive the turbine to do work and drive the generator to rotate, so as to convert the pressure potential energy into electric energy. However, heat needs to be continuously released during compressed gas energy storage and absorbed when the gas expands to do work. Therefore, technical means such as heat exchange and heat storage need to be adopted. In practical applications, it is not only time-consuming and laborious and costly, but also the heat energy loss will occur during the heat energy exchange and heat storage processes, resulting in a reduction in the conversion efficiency of the energy storage device. In addition, storing compressed gas requires a huge underground space, and not all regions have such construction conditions. The above reasons have led to the limited application of this energy storage method. Summary of the Invention

[0004] This disclosure aims to solve at least one of the technical problems in the related art to some extent.

[0005] To this end, this disclosure provides a constant pressure energy storage device without heat storage and a new energy power generation system. This disclosure utilizes the principle that certain gases can dissolve in a solution and separate from the solution under certain conditions to achieve energy storage and energy release without heat exchange and heat storage, allowing compressed gas with a constant pressure to store and release energy, and can achieve long-term, large-capacity and various energy storage and energy release methods. This disclosure connects the above energy storage device between the existing wind power or photovoltaic power generation system and the power grid, so that the electric energy generated by the above two new energy sources is not directly input into the main power grid, but stored by the above energy storage device; when the main power grid needs electric energy, the above energy storage device releases energy, and the energy release process of the above energy storage device is fully controllable, solving the technical problems brought by the unstable power generation of the two new energy sources, and at the same time creating conditions for establishing a power supply pattern mainly based on new energy in some regions and exploring the gradual withdrawal of coal-fired power plants from the power system.

[0006] To achieve the above object, this disclosure adopts the following technical solutions:

[0007] A constant pressure energy storage device provided in the first aspect of this disclosure includes a sub-control system and a plurality of energy storage working units, and each energy storage working unit is respectively connected to the sub-control system through a control cable;

[0008] The energy storage working unit includes a liquid storage tank, a hydraulic unit, an energy storage mechanism, and a pressure regulating mechanism, which are sequentially connected through a pipeline provided with a valve. The hydraulic unit is also connected to the power cable of the new energy power generation system through a power cable. The liquid storage tank stores a working liquid, and above the liquid level is a gas with a constant first pressure. The energy storage mechanism and the pressure regulating mechanism respectively contain a working liquid and a dissolving liquid, and above the liquid level in the energy storage mechanism is a working gas with a second pressure, the second pressure is higher than the first pressure, and the solubility of the working gas in the working liquid and the dissolving liquid is different. When the pressure of the working gas in the energy storage mechanism shows a continuous changing trend, the pressure regulating mechanism is used to change the dissolved amount of the working gas in the dissolving liquid, and under the action of the hydraulic unit, the working liquid circulates between the energy storage mechanism and the liquid storage tank, so that the working gas in the energy storage mechanism is maintained at a second pressure higher than the first pressure to achieve energy storage and energy release.

[0009] The sub-control system is used to turn on or off a corresponding number of the energy storage working units according to the energy storage or energy release capacity requirements of the total control system of the new energy power generation system, control and monitor the equipment status in each energy storage working unit, transmit the status and parameters of the energy storage device to the total control system at any time, and regulate the energy storage device according to the instructions issued by the total control system.

[0010] In some embodiments, the working liquid is used as hydraulic oil, and the working gas is a single gas or a mixed gas that is difficult to dissolve in the working liquid at normal temperature, easy to dissolve in the dissolving liquid, and does not undergo a phase change within a set working pressure range. When the working gas dissolves in the working liquid or reacts chemically with the working liquid, a flexible diaphragm needs to be provided between the working gas and the working liquid. The dissolving liquid does not produce an obvious thermal effect when dissolving the working gas.

[0011] In some embodiments, the second pressure is selected in the range of 1 MPa to 100 MPa, and the air pressure difference between the energy storage mechanism and the liquid storage tank is not less than 0.9 MPa. During energy storage, the air pressure difference between the energy storage mechanism and the pressure regulating mechanism is controlled in the range of 0.1 MPa to 0.3 MPa.

[0012] In some embodiments, the hydraulic unit includes a hydraulic motor, a hydraulic pump, and a generator motor shared by both. The generator motor is respectively connected to the hydraulic motor and the hydraulic pump through corresponding clutches. The generator motor is connected to the power line of the new energy power generation system through the power cable. Both ends of the hydraulic motor are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines provided with corresponding valves. Both ends of the hydraulic pump are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines provided with corresponding valves.

[0013] In some embodiments, the energy storage mechanism includes a sealed working tank, which contains the working liquid and the working gas. A first interface and a second interface are respectively provided at the bottom and the top of the working tank; the air pressure regulating mechanism includes a sealed regulating tank, and a gas-liquid mixer and a gas-liquid separator installed on the regulating tank. A third interface and a fourth interface are respectively provided at the bottom and the top of the regulating tank. A dissolving liquid is contained in the regulating tank. The second interface is respectively connected to the third interface and the fourth interface through pipelines provided with corresponding valves; the liquid storage tank adopts a sealed tank or a tank with its top communicating with the atmosphere.

[0014] In some embodiments, the gas-liquid mixer adopts any one of a stirrer, a flow guide device, and a sprayer. The stirrer and the flow guide device are arranged at the third interface, and the sprayer is arranged at the top inside the regulating tank;

[0015] The gas-liquid separator adopts any one of a heater, an ultrasonic vibrator, and a membrane separator, and is arranged at the third interface.

[0016] In some embodiments, when the gas-liquid mixer adopts the sprayer, the gas-liquid mixer further includes a mixer arranged at the third interface, a spray pipe connected between the sprayer and the third interface, and a spray liquid pump arranged on the spray pipe.

[0017] In some embodiments, the sub-control system includes a first operation controller and a sensing unit, a first grid connection control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit, and a first user interface connected thereto; the sensing unit includes a liquid level sensor for detecting the liquid level position of the working fluid in the energy storage mechanism, a pressure sensor for detecting the air pressure in the energy storage mechanism, and a rotational speed sensor for detecting the rotational speed of the hydraulic unit; when the liquid level in the energy storage mechanism is higher than the first position, the first operation controller controls the hydraulic unit to stop the working fluid from flowing from the liquid storage tank to the energy storage mechanism; when the liquid level in the energy storage mechanism is lower than the second position, the first operation controller controls the hydraulic unit to stop the working fluid from flowing from the energy storage mechanism to the liquid storage tank; when the air pressure in the energy storage mechanism continuously exceeds the second air pressure, the first operation controller connects the pipeline between the top of the energy storage mechanism and the bottom of the air pressure regulating mechanism, and at the same time closes the pipeline between the top of the energy storage mechanism and the top of the air pressure regulating mechanism, and makes the working gas enter the dissolving liquid in the air pressure regulating mechanism through the air pressure regulating mechanism to be absorbed and dissolved by it, so that the air pressure in the energy storage mechanism no longer rises and remains stable; when the air pressure in the energy storage mechanism continuously is lower than the second air pressure, the first operation controller connects the pipeline between the top of the air pressure regulating mechanism and the top of the energy storage mechanism, and at the same time closes the pipeline between the bottom of the air pressure regulating mechanism and the top of the energy storage mechanism, and separates the working gas absorbed by the dissolving liquid through the air pressure regulating mechanism and enters the energy storage mechanism, so that the air pressure in the energy storage mechanism no longer drops and remains stable; the first operation controller controls the rotational speed of the hydraulic unit to operate within a set rotational speed range according to the rotational speed sensor; the first operation controller senses the real-time energy storage and energy release margin of the energy storage working unit according to the liquid level sensor; the first grid connection control unit is used to transmit the electric energy generated by the energy storage device to the main grid; the first safety protection unit is used to handle emergencies and timely shut down the problematic energy storage working unit or even the entire energy storage device when the parameters exceed the preset working range; the first monitoring unit is used to monitor the working state of the energy storage working unit in real time and transmit the data to the first operation controller, the first safety protection unit, and the first user interface; the first communication interface circuit is used to realize data communication during the working process of the energy storage device; the first user interface is used to input user instructions, change parameters, display the operation state, data, and fault conditions of the energy storage device; the first operation controller is used for the operation monitoring of the energy storage device, including start-stop control, control of each electronic device, and grid monitoring;

[0018] The sub-control system controls the working modes of each energy storage working unit according to the energy storage and energy release instructions of the total control system of the new energy power generation system: when the electric energy generated by the new energy power generation site is less, the total control system instructs the sub-control system of the energy storage device to start one or a few of the energy storage working units to participate in energy storage; when the electric energy generated by the new energy power generation site is close to full load, the total control system instructs the sub-control system to start all the energy storage working units to participate in energy storage at the same time; when the electric energy generated by the new energy power generation site is gradually increasing, the total control system instructs the sub-control system to gradually start one or more energy storage working units to participate in energy storage one after another.

[0019] In some embodiments, the operation process of the energy storage device includes:

[0020] During energy storage operation: the sub-control system opens a corresponding number of energy storage working units according to the energy storage capacity requirement of the total control system. The sub-control system first controls the first valve, the second valve and the third valve to respectively connect the pipelines between the liquid storage tank and the hydraulic unit, between the hydraulic unit and the bottom of the energy storage mechanism, and between the top of the energy storage mechanism and the bottom of the air pressure regulating mechanism, and at the same time controls the sixth valve to close the pipeline between the top of the air pressure regulating mechanism and the top of the energy storage mechanism, and then connects the power cable to start the hydraulic unit. The working fluid enters the energy storage mechanism from the liquid storage tank, causing the liquid level in the energy storage mechanism to rise; when the air pressure in the energy storage mechanism is continuously greater than the second air pressure, the sub-control system controls the air pressure regulating mechanism to make the dissolving liquid absorb and dissolve the working gas, so that the air pressure in the energy storage mechanism is maintained at the second air pressure. When the liquid level in the energy storage mechanism reaches the allowable highest position, the sub-control system first disconnects the power cable and brakes the hydraulic unit, and at the same time closes all valves, thereby realizing the conversion of electric energy into the pressure potential energy of the working fluid and storing it; if there is still surplus electric energy to be stored, the sub-control system successively opens the remaining energy storage working units until the liquid level of the working fluid in the energy storage mechanism of all the energy storage working units in the entire energy storage device reaches the allowable highest position, realizing full-load energy storage, and the energy storage operation ends; when there is an unexpected situation of no energy storage capacity during the energy storage process of a single or part of the energy storage working units, the sub-control system disconnects the power cable and brakes the hydraulic unit, and then closes all valves, and the energy storage operation is suspended; if there is still an energy storage requirement later, the energy storage working units with the suspended energy storage operation continue the energy storage operation until the full-load energy storage of the energy storage working units is realized, and finally the full-load energy storage of the energy storage device is realized;

[0021] During the energy release operation: the sub-control system turns on the corresponding number of energy storage working units according to the required energy release capacity. The sub-control system first connects the power cable to start the hydraulic unit, and at the same time controls the fourth valve, the fifth valve and the sixth valve to connect the pipelines between the liquid storage tank and the hydraulic unit, between the hydraulic unit and the bottom of the energy storage mechanism, and between the top of the energy storage mechanism and the top of the air pressure regulating mechanism respectively, and at the same time closes the third valve. Under the action of the working air pressure, the liquid level of the working liquid in the energy storage mechanism drops, and this working liquid acts on the hydraulic unit to generate electricity, and then enters the liquid storage tank, becoming a liquid with only the first air pressure. As the liquid level in the energy storage mechanism drops, when the air pressure in the energy storage mechanism is lower than the second air pressure, the sub-control system controls the air pressure regulating mechanism to separate the working air in the dissolved liquid and enter the energy storage mechanism, so that the air pressure in the energy storage mechanism is maintained at the second air pressure. When the liquid level in the energy storage mechanism reaches the allowable lowest position, the sub-control system disconnects the power cable and brakes the hydraulic unit, and at the same time closes all valves, and the energy release of the energy storage working unit ends, thereby converting the pressure potential energy of the working liquid into electrical energy; if the energy storage device still has an energy release requirement, the sub-control system turns on the remaining corresponding number of energy storage working units until all the energy storage working units in the energy storage device achieve full-load energy release; when a single or part of the energy storage working units are in the process of energy release and accidentally do not require energy release, the sub-control system first disconnects the power cable and brakes the hydraulic unit, then closes all valves, and the energy release operation is suspended. If there is still an energy release requirement later, the energy storage working units whose energy release operations have been suspended will continue the energy release operation until the full-load energy release of the energy storage working unit, and finally achieve the full-load energy release of the energy storage device.

[0022] A new energy power generation system provided in the second aspect of the present disclosure, the new energy power generation system is a wind or photovoltaic power generation system, including a total control system and at least one wind or photovoltaic power generation field that supplies power to the main power grid through an energy storage device. The energy storage device adopts the energy storage device according to any one of the embodiments of the first aspect of the present disclosure. A boost control device is also connected between the energy storage device and the main power grid; each wind or photovoltaic power generation field is configured with at least three such energy storage devices. The maximum rated power generation of the wind or photovoltaic power generation field is equal to the energy storage power of one energy storage device. When the wind or photovoltaic power generation field generates electricity, one energy storage device performs energy storage operation, one energy storage device can be put into energy release operation, and at least one energy storage device remains in a full-load energy storage state; the sub-control systems in the wind or photovoltaic power generation field, the boost control device and each energy storage device are all connected to the total control system through control cables, and power is transmitted between the wind or photovoltaic power generation field, the energy storage device and the main power grid through power cables;

[0023] The total control system is used to turn on and off the corresponding energy storage device according to the power generation situation and operating conditions of the wind or photovoltaic power generation field for energy storage and transmit electric energy to the main power grid, and monitor the operating conditions of the power generation system.

[0024] The present disclosure has the following features and beneficial effects:

[0025] The present disclosure utilizes the principle that certain gases can dissolve in a dissolution liquid and be separated from the dissolution liquid under certain conditions to construct a compressed gas energy storage device that does not require heat exchange and heat storage and can maintain a constant air pressure. This not only avoids the heat release required for air compression during energy storage and the heat absorption required for air expansion during energy release, as well as the devices such as heat storage and heat exchange that need to be set up, but also avoids problems such as heat loss and a decrease in the efficiency of the energy storage device caused by heat exchange and long-term heat preservation, thereby achieving long-term, high-efficiency, large-capacity, and multiple-mode energy storage and energy release. Specifically, the energy storage capacity of each energy storage device can store the electric energy generated by the corresponding wind power generation field or photovoltaic power generation field at full load for a long time within a certain period. During the period when the wind power generation field or photovoltaic power plant has a reduced output or no output at all due to natural reasons, multiple energy storage devices continue to generate electricity; in each energy storage device, the energy storage working units in one or more energy storage devices can participate in energy storage or energy release simultaneously, or the energy storage working units can participate in energy storage or energy release sequentially. This can not only ensure energy storage in the wind power generation field under light wind or continuously changing wind speeds or in the photovoltaic power generation field under low-intensity light or continuously changing light intensities, but also meet the flexible requirements of the main power grid for the electric energy released by the energy storage device. More importantly, the wind power generation field or photovoltaic power generation field does not directly send electricity to the main power grid, but generates electricity and is connected to the grid through the energy storage device, and the electric energy generated by the energy storage device remains constant, thus solving the adverse effects of wind energy or solar energy power generation methods on the main power grid and creating conditions for increasing the proportion of the above two new energy power generations in the regional power grid. Description of the Drawings

[0026] Figure 1 is a layout schematic diagram of a constant air pressure energy storage device provided by an embodiment of the first aspect of the present disclosure;

[0027] Figure 2 is Figure 1 a side view of a single energy storage working unit in the energy storage device shown;

[0028] Figure 3 is Figure 1 a schematic diagram of a pneumatic pressure regulating mechanism with a sprayer in a single energy storage working unit in the energy storage device shown;

[0029] Figure 4 is Figure 1 a schematic diagram of the structure of the sub-control system in the energy storage device shown;

[0030] Figure 5 It is a schematic structural diagram of a new energy power generation system with the above energy storage device provided by an embodiment of the second aspect of the present disclosure.

[0031] Reference numerals:

[0032] 100 - energy storage working unit, 110 - energy storage mechanism, 111 - working tank, 120 - air pressure regulating mechanism, 121 - regulating tank, 122 - gas-liquid mixer, 122a - sprayer, 122b - mixer, 122c - spray pipe, 122d - spray liquid pump, 123 - gas-liquid separator, 124 - dissolving liquid, 130 - hydraulic unit, 131 - hydraulic motor, 132 - power generation motor, 133 - hydraulic pump, 140 - liquid storage tank, 151 - first valve, 152 - second valve, 153 third valve, 154 - fourth valve, 155 - fifth valve, 156 - sixth valve, 157 - seventh valve, 160 - working liquid, 170 - pipeline, 180 - working gas, a - first interface, b - second interface, c - third interface, d - fourth interface, e - fifth interface, 190 - frame;

[0033] 200 - control cable;

[0034] 300 - sub-control system, 310 - sensing unit, 311 - liquid level sensor, 312 - pressure sensor, 313 - rotational speed sensor, 320 - first operation controller, 330 - first grid connection control unit, 340 - first safety protection unit, 350 - first monitoring unit, 360 - first communication interface circuit, 370 - first user interface;

[0035] 400 - new energy power generation system, 410 - new energy power generation field, 411 - wind turbine generator set, 412 - wind farm power collection system, 413 - wind farm control system, 420 - energy storage device, 430 - total control system, 440 - power cable, 450 - boost control device; 500 - main power grid. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] Rather, this application covers any alternatives, modifications, equivalent methods, and schemes defined by the claims that are within the spirit and scope of this application. Further, in order to enable the public to better understand this application, in the following detailed description of this application, some specific details are described in detail. Those skilled in the art can fully understand this application even without the description of these details.

[0038] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the referred base or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present disclosure. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present disclosure, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0039] In the description of the present disclosure, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0040] In the present disclosure, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0041] See Figures 1 to 4, A constant pressure energy storage device provided by an embodiment of the first aspect of the present disclosure includes a sub-control system 300 and a plurality of energy storage working units 100. Each energy storage working unit 100 is respectively connected to the sub-control system 300 through a control cable 200;

[0042] The energy storage working unit 100 includes a liquid storage tank 140, a hydraulic unit 130, an energy storage mechanism 110, and a pressure regulating mechanism 120 that are sequentially connected through a pipeline 170 provided with a valve. The hydraulic unit 130 is also connected to the power cable of the new energy power generation system through a power cable; the liquid storage tank 140 stores a working liquid 160, and the gas above its liquid level has a constant first pressure; the energy storage mechanism 110 and the pressure regulating mechanism 120 respectively contain the working liquid 160 and the dissolving liquid 124, and a working gas 180 with a second pressure is contained above the liquid level in the energy storage mechanism 110. The second pressure is higher than the first pressure, and the solubility of the working gas 180 in the working liquid 160 and the dissolving liquid 124 is different. When the pressure of the working gas 180 in the energy storage mechanism 110 shows a continuous change trend, the pressure regulating mechanism 120 is used to change the dissolved amount of the working gas 180 in the dissolving liquid 124, and under the action of the hydraulic unit 130, the working liquid 180 circulates between the energy storage mechanism 110 and the liquid storage tank 140, so that the working gas 180 in the energy storage mechanism 110 is maintained at a second pressure higher than the first pressure to achieve energy storage and energy release;

[0043] The sub-control system 300 is used to turn on or turn off the corresponding number of energy storage working units 100 according to the energy storage or energy release capacity requirements of the total control system of the new energy power generation system, control and monitor the equipment status in each energy storage working unit 100, transmit the status and parameters of this constant pressure energy storage device to the total control system at any time, and regulate this constant pressure energy storage device according to the instructions issued by the total control system.

[0044] Furthermore, the sub-control system 300 controls the working modes of each energy storage working unit 100 according to the energy storage and energy release instructions of the total control system of the new energy power generation system (mainly for wind power or photovoltaic power generation systems): when the electric energy generated by the new energy power generation site is less, the total control system of the new energy power generation system instructs the sub-control system 300 of this constant pressure energy storage device to start one or a few energy storage working units 100 to participate in energy storage; when the electric energy generated by the new energy power generation site is close to full load, the total control system instructs the sub-control system 300 to start all energy storage working units 100 to participate in energy storage at the same time; when the electric energy generated by the new energy power generation site is gradually increasing, the total control system instructs the sub-control system 300 to start the corresponding number of energy storage working units 100 to participate in energy storage successively.

[0045] In some embodiments, the number of energy storage working units 100 in the constant air pressure energy storage device can be 3 or more, even dozens, to achieve complete consumption of new energy power generation, and can continue to supply electrical energy to the power system when the new energy power generation plant cannot generate electricity due to natural reasons.

[0046] In some embodiments, referring to Figure 2 , the hydraulic unit 130 includes a hydraulic motor 131, a hydraulic pump 133, and a motor-generator 132 shared by both, which is used to realize the circulation of the working fluid 160 between the energy storage mechanism 110 and the liquid storage tank 140. The motor-generator 132 is connected to the hydraulic motor 131 and the hydraulic pump 133 through two clutches respectively, and the motor-generator 132 is connected to the power cable of the new energy power generation system through a power cable. When the energy storage working unit 100 works normally, one of the hydraulic pump 133 and the hydraulic motor 131 is connected to the motor-generator 132 and is in an operating state; specifically, when the energy storage working unit 100 participates in the energy storage operation, the clutch between the hydraulic pump 133 and the motor-generator 132 is connected through the sub-control system 300, and the clutch between the hydraulic motor 131 and the motor-generator 132 is disconnected; when the energy storage working unit 100 participates in the energy release operation, the clutch between the hydraulic pump 133 and the motor-generator 132 is disconnected through the sub-control system 300, and the clutch between the hydraulic motor 131 and the motor-generator 132 is connected.

[0047] Referring to Figure 2 , Figure 3 , the energy storage mechanism 110 includes a sealed working tank 111. The bottom and top of the working tank 111 are respectively provided with a first interface a and a second interface b. The lower and upper parts of the working tank 111 respectively contain a working fluid 160 and a working gas 180. The air pressure regulating mechanism 120 includes a sealed regulating tank 121, a gas-liquid mixer 122 and a gas-liquid separator 123 installed on the regulating tank 121. The bottom and top of the regulating tank 121 are respectively provided with a third interface c and a fourth interface d. The regulating tank 121 contains a dissolving liquid 124; the gas-liquid mixer 122 is installed at the third interface c and / or the fourth interface d, which is used to ensure that the working gas 180 discharged from the working tank 111 is absorbed by the dissolving liquid 124 in the regulating tank 121; the gas-liquid separator 123 is installed at the third interface c, which is used to separate the working gas 180 absorbed by the dissolving liquid 124 from the dissolving liquid 124, and is discharged from the fourth interface d out of the regulating tank 121 and then enters the upper part of the working tank 111 through the second interface b. The liquid storage tank 140 adopts a sealed tank or a tank with its top communicating with the atmosphere.

[0048] Further, the working fluid 160 can be various liquids that can be used as hydraulic oil. The working gas 180 should meet the requirements that it is difficult to dissolve in the working fluid 160 at normal temperature, is easy to dissolve in the dissolving fluid 124, and does not undergo a phase change (from gaseous to liquid or from liquid to gaseous) within the set working pressure range. A single gas or a mixed gas can be used. It is required that the dissolving fluid 124 does not produce an obvious thermal effect when dissolving the working gas 180. The combinations of components that can be dissolved in the working gas 180 corresponding to the common dissolving fluid 124 are: water corresponding to carbon dioxide gas, and fluorocarbon liquid corresponding to oxygen or carbon dioxide gas. If the working gas 180 dissolves in the working fluid 160 or can chemically react with the working fluid 160, a flexible diaphragm needs to be set between the working gas 180 and the working fluid 160 to isolate the two. The air pressure value of the working gas 180 in the working tank 111, that is, the second pressure, should be selected within the range of 1 MPa to 100 MPa and meet the above requirements. To ensure that the hydraulic unit 130 has a high efficiency, the air pressure difference between the working gas 180 in the working tank 111 and the air pressure in the liquid storage tank 140 is not less than 0.9 MPa; during energy storage, to ensure that the working gas 180 can smoothly enter the regulating tank 121, there should be an air pressure difference between the working gas 180 in the working tank 111 and the working gas 180 in the regulating tank 121, and this air pressure difference is controlled within the range of 0.1 MPa to 0.3 MPa. The working gas 180 in this embodiment is preferably a working gas formed by mixing carbon dioxide gas and nitrogen gas in a ratio of 2:1 and with an air pressure value of 30 MPa. Water is preferably used as the dissolving fluid 124. The carbon dioxide in the working gas 180 can be partially dissolved in water at a higher pressure through the gas-liquid mixer 122. The mixed gas of carbon dioxide gas and nitrogen gas is used because nitrogen is insoluble in water, which can avoid the decrease in the working gas pressure above the regulating tank 121 caused by all the working gas of a single carbon dioxide gas dissolving in water and affecting the subsequent energy release operation.

[0049] Further, the liquid level of the working fluid 160 in the working tank 111 has an allowable highest position and an allowable lowest position. When the liquid level of the working fluid 160 is between its allowable highest position and lowest position, the energy storage working unit 100 can store or release energy normally. Let the allowable highest position of the liquid level of the working fluid 160 in the working tank 111 be the first position, and the allowable lowest position be the second position, corresponding to the two states of the energy storage working unit 100 being at full-load energy storage and full-load energy release respectively.

[0050] Further, the working tank 111, the regulating tank 121, and the liquid storage tank 140 are all vertical tanks. To increase the energy storage density and increase the pressure of the working gas, the working tank 111 and the regulating tank 121 adopt slender tank bodies with a circular cross-section.

[0051] Furthermore, the gas-liquid mixer 122 can be any one of a stirrer, a flow deflector, and a sprayer, all of which are commercially available products. Among them, the stirrer and the flow deflector are arranged at the third interface c at the bottom of the regulating tank 121. The flow deflector is a mechanism for introducing the working gas 180 from the bottom of the dissolved liquid 124 in the regulating tank 121 and passing through the dissolved liquid 124 in the form of fine bubbles. Refer to Figure 3 , the sprayer 122a is arranged at the top inside the regulating tank 121 and is a mechanism for spraying the dissolved liquid 124 into the working gas 180 in the regulating tank 121 in the form of fine liquid streams or droplets. At this time, the gas-liquid mixer 122 further includes a mixer 122b arranged at the third interface c of the regulating tank 121, a spray pipe 122c connected between the sprayer 122a and the third interface c, and a spray liquid pump 122d arranged on the spray pipe 122c to enhance the dissolution effect of the dissolved liquid 124 on the working gas 180.

[0052] Furthermore, the gas-liquid separator 123 can be any one of a heater (heating temperature not exceeding 80 degrees Celsius), an ultrasonic vibrator, and a membrane separator, all of which are commercially available products. The gas-liquid separator 123 separates the working gas 180 absorbed by the dissolved liquid 124 from the dissolved liquid 124 by means of heating, vibration, or the selectivity of the membrane. The gas-liquid separator 123 in this embodiment preferably uses an ultrasonic vibrator.

[0053] In some embodiments, a fifth interface e is provided at the bottom of the liquid storage tank 140. The fifth interface e is connected to one end of the hydraulic pump 133 through a pipeline provided with a first valve 151. The other end of the hydraulic pump 133 is connected to the first interface a at the bottom of the working tank 111 through a pipeline provided with a second valve 152. The fifth interface e is connected to one end of the hydraulic motor 131 through a pipeline provided with a fourth valve 154. The other end of the hydraulic motor 131 is connected to the first interface a at the bottom of the working tank 111 through a pipeline provided with a fifth valve 155. The working liquid 180 enters or exits the working tank 111 through the first interface a. The second interface b at the top of the working tank 111 is connected to the third interface c at the bottom of the regulating tank 121 through a pipeline provided with a third valve 153. The second interface b is also connected to the fourth interface d at the top of the regulating tank 121 through a pipeline provided with a sixth valve 156. The working gas 180 enters or exits the working tank 111 through the second interface b. The working gas 180 enters the regulating tank 121 through the third interface c and exits the regulating tank 121 through the fourth interface d.

[0054] Optionally, maintenance pipelines are respectively provided at the second interface b of the working tank 111 and the fourth interface d of the regulating tank 121. A seventh valve 157 is provided on this maintenance pipeline, which is convenient for emptying the working gas 180 inside the energy storage mechanism 110 and the air pressure regulating mechanism 120 during maintenance. The seventh valve 157 is normally closed and is only opened during maintenance.

[0055] In some embodiments, the energy storage working unit 100 further includes a frame 190 for installing and fixing the energy storage mechanism 110, the air pressure regulating mechanism 120, the hydraulic unit 130, and the liquid storage tank 140, ensuring the structural stability during their operation. In addition, the frame 190 is designed as a closed structure so that the energy storage and energy release processes of the energy storage working unit 100 are not affected by weather changes.

[0056] In some embodiments, refer to Figure 2 、 Figure 4, the sub-control system 300 includes a first operation controller 320 and a sensing unit 310, a first grid connection control unit 330, a first safety protection unit 340, a first monitoring unit 350, a first communication interface circuit 360, and a first user interface 370 connected thereto; the sensing unit 310 includes a liquid level sensor 311 for detecting the liquid level position of the working fluid 160 in the energy storage mechanism 110, a pressure sensor 312 for detecting the pressure of the working gas 180 in the energy storage mechanism 110, a differential pressure sensor for measuring the pressure difference and change between the two tanks, and a rotational speed sensor 313 for detecting the rotational speed of the power generation motor 132; during the energy storage operation stage, the first valve 151, the second valve 152, and the third valve 153 are all controlled by the first operation controller 320 to be in the open state, and the fourth valve 154, the fifth valve 155, and the sixth valve 156 are all controlled by the first operation controller 320 to be in the closed state. When the liquid level of the working fluid 160 in the energy storage mechanism 110 reaches the upper first position, the first operation controller 320 controls the hydraulic pump 133 to stop, and at the same time, makes the first valve to the sixth valve all in the closed state, and the energy storage working unit 100 stops energy storage; during the energy release operation stage, the fourth valve 154, the fifth valve 155, and the sixth valve 156 are all controlled by the first operation controller 320 to be in the open state, and the first valve 151, the second valve 152, and the third valve 153 are all controlled by the first operation controller 320 to be in the closed state. When the liquid level of the working fluid 160 in the energy storage mechanism 110 is lower than the second position, the first operation controller 320 controls the hydraulic motor 131 to stop, and at the same time, makes the first valve to the sixth valve all in the closed state, and the energy storage working unit 100 stops energy release; when the air pressure in the working tank 111 and the air pressure regulating tank 121 is higher than the set air pressure and gradually increases, the first operation controller 320 controls the third valve 153 to connect the pipeline 170 between the second interface b at the top of the working tank 111 and the third interface c at the bottom of the regulating tank 121, and at the same time controls the sixth valve 156 to close the pipeline 170 between the second interface b at the top of the working tank 111 and the fourth interface d at the top of the regulating tank 121, so that the working gas 180 enters the dissolving liquid 124 in the lower part of the regulating tank 121, and then is absorbed by the dissolving liquid 124 through the gas-liquid mixer 122 at the lower part of the regulating tank 121, so that the air pressure in the working tank 111 and the regulating tank 121 no longer rises and remains stable; on the contrary, when the air pressure in the working tank 111 and the regulating tank 121 is lower than the set air pressure and gradually decreases, the first operation controller 320 controls the sixth valve 156 to connect the pipeline 170 between the fourth interface d at the top of the regulating tank 121 and the second interface b at the top of the working tank 111, and at the same time separates the working gas 180 absorbed by the dissolving liquid 124 through the gas-liquid separator 123 and enters the upper chamber in the regulating tank 121 and the working tank 111, so that the air pressure of the working gas 180 no longer drops and remains stable;When the rotational speed of the power generation motor 132 detected by the rotational speed sensor 313 exceeds the set rotational speed range, the first operation controller 320 controls the excitation current voltage of the power generation motor 132 to make the rotational speed of the power generation motor 132 operate within the set rotational speed range, so as to ensure that the working load or power generation power of the power generation motor does not exceed the specified working range. The first grid connection control unit 330 is used to transmit the electric energy generated by this energy storage device to the main power grid. The first safety protection unit 340 is used to handle emergencies. When the parameters exceed the preset working range, it timely shuts down the problematic energy storage working unit 100, or even the entire energy storage device. The first monitoring unit 350 is used to monitor the working state of the energy storage working unit 100 in real time and transmit the data to the first operation controller 320, the first safety protection unit 340, and the first user interface 370. The first communication interface circuit 360 is used to realize data communication during the working process of the energy storage device. The first user interface 370 is used to input user instructions, change parameters, and display the operation state, data, and fault conditions of the energy storage device; the first operation controller 320 is used for the operation monitoring of the energy storage device, including start-stop control, control of each electronic device, and power grid monitoring.;

[0057] In some embodiments, the operation process of the above-mentioned energy storage device provided in the first aspect embodiment of the present disclosure includes:

[0058] During energy storage operation: The sub-control system 300 activates the corresponding number of energy storage working units 100 according to the energy storage capacity requirements of the main control system. The sub-control system 300 first controls the first valve 151, the second valve 152, and the third valve 153 to connect the pipelines 170 from the liquid storage tank 140 to the hydraulic pump 133, from the hydraulic pump 133 to the working tank 111, and between the upper part of the working tank 111 and the lower part of the regulating tank 121 respectively. At the same time, it controls the sixth valve 156 to close the connecting pipeline 170 between the upper part of the regulating tank 121 and the upper part of the working tank 111. Then it connects the power cable to start the power generation motor 132, and controls the clutch to connect the power generation motor 132 to the hydraulic pump 133. The working fluid 160 enters the working tank 111 from the liquid storage tank 140 under the action of the hydraulic pump 133, causing the liquid level in the working tank 111 to rise. When the air pressure in the upper part of the working tank 111 is greater than the air pressure above the regulating tank 121 and higher than the set air pressure for a period of time, the gas-liquid mixer 122 in the regulating tank 121 absorbs and dissolves the working gas 180 to keep the air pressure in the working tank 111 basically constant. When the liquid level of the working fluid 160 reaches the first position (the highest allowable liquid level of the working fluid) in the upper part of the working tank 111, the sub-control system 300 first disconnects the power cable and brakes the power generation motor 132, and at the same time closes the first valve 151, the second valve 152, and the third valve 153, thus converting electrical energy into the pressure potential energy of the working fluid 160 and storing it. If there is still surplus electrical energy to be stored, the sub-control system 300 successively activates the remaining energy storage working units 100 until the liquid levels of the working fluid 160 in all the energy storage working units of the entire energy storage device rise to the first positions in the upper parts of their respective working tanks 111, achieving full-load energy storage and ending the energy storage operation. When an unexpected situation of no energy storage capacity occurs during the energy storage process of a single or some energy storage working units 100, the sub-control system 300 disconnects the power cable, brakes the power generation motor 132, and then closes the first valve 151, the second valve 152, and the third valve 153, pausing the energy storage operation. If there are still energy storage requirements later, the energy storage working units 100 with the paused energy storage operation continue the energy storage operation until full-load energy storage of the energy storage working units 100 is achieved, and finally full-load energy storage of the energy storage device is realized;

[0059] During the energy release operation: The sub-control system 300 activates the corresponding number of energy storage working units 100 according to the required energy release capacity. The sub-control system 300 first connects the power generation motor 132 to the hydraulic motor 131 through the clutch, then connects the power cable to start the power generation motor 132. At the same time, it controls the fourth valve 154, the fifth valve 155, and the sixth valve 156 to connect the connecting pipelines 170 from the liquid storage tank 140 to the hydraulic motor 131, from the hydraulic motor 131 to the working tank 111, and between the upper part of the working tank 111 and the upper part of the regulating tank 121 respectively, and ensures that the third valve 153 is in the closed state. Under the pressure of the working gas 180, the liquid level of the working liquid 160 in the working tank 111 drops. The working liquid 160 with a relatively high pressure acts on the hydraulic motor 131 to drive the power generation motor 132 to rotate and generate electricity. After doing work on the hydraulic motor 131, the working liquid 160 with a relatively high pressure enters the liquid storage tank 140 and becomes a liquid that only maintains the first air pressure (when the liquid storage tank 140 is connected to the atmosphere, it is one atmosphere). When the liquid level in the working tank 111 drops and the air pressure in the upper part of the working cylinder 111 and the upper part of the regulating tank 121 is lower than the specified air pressure and continues to drop, the sub-control system 300 controls the gas-liquid separator 123 at the lower part of the regulating tank 121 to separate the working gas 180 in the dissolved liquid 124 and enter the upper cavity in the working tank 111 through the upper cavity in the regulating tank 121, so that the air pressure in the working tank 111 no longer drops and remains constant. When the liquid level of the working liquid 160 is lower than the second position at the lower part of the working tank 111, the sub-control system 300 disconnects the power cable and brakes the power generation motor 132. At the same time, it closes the fourth valve 154, the fifth valve 155, and the sixth valve 156, and the energy release of the energy storage working unit 100 ends. In this way, the pressure potential energy of the working liquid 160 is converted into electric energy; if the energy storage device still has energy release requirements, the sub-control system 300 activates the remaining corresponding number of energy storage working units 100 until the entire energy storage device realizes full-load energy release for all energy storage working units 100; when an unexpected situation where energy release is not required occurs during the energy release process of a single or part of the energy storage working units 100, the sub-control system 300 first disconnects the power cable and brakes the power generation motor 132, then closes the fourth valve 154, the fifth valve 155, and the sixth valve 156, and the energy release operation is suspended. If there are still energy release requirements in the future, the energy storage working unit 100 whose energy release operation has been suspended will continue the energy release operation until the energy storage working unit 100 realizes full-load energy release, and finally realizes full-load energy release of the energy storage device.

[0060] It can be understood that by adopting the principle that the working gas 180 can dissolve in the dissolved liquid 124 and cannot (or hardly) dissolve in the working liquid 160, it is possible not to set up a heat storage device. Also, since there is no heat energy loss during energy storage and energy release, the efficiency of the energy storage device is improved, and long-term energy storage is achieved.

[0061] See Figure 5, a new energy power generation system 400 provided by an embodiment of the second aspect of the present disclosure includes a total control system 430 and at least one new energy power generation farm 410 that supplies power to the main power grid 500 through an energy storage device 420( Figure 5 shown as a wind power farm in), the energy storage device 420 adopts the air pressure constant energy storage device provided by the embodiment of the first aspect of the present disclosure, and a boost control device 450 is also connected between the energy storage device 420 and the main power grid 500; each new energy power generation farm 410 is configured with at least three or more energy storage devices 420. To ensure long-term energy storage and release, the number of energy storage devices 420 is 3 to 36, so as to ensure that the new energy power generation farm can continue to supply power to the main power grid 500 when it cannot generate electricity due to natural reasons. The maximum rated power generation of the new energy power generation farm 410 is equal to the energy storage power of one energy storage device 420. When the new energy power generation farm 410 generates electricity, only one energy storage device 420 is in the energy storage state, that is, it is performing energy storage operations (to avoid the problem of tripping of the new energy power generation farm caused by too large a load), one energy storage device 420 is in the energy release state, that is, it is supplying power to the main power grid 500, and at least one energy storage device 420 is in the state after full-load energy storage, ready to supply power to the main power grid 500; the sub-control systems 300 in the new energy power generation farm 410, the boost control device 450, and each energy storage device 420 are all connected to the total control system 430 through control cables 200, and power is transmitted between the new energy power generation farm 410, the energy storage device 420, and the main power grid 500 through power cables 440; the total control system 430 is used to start and stop the corresponding energy storage device 420 for energy storage and output power to the main power grid 500 according to the power generation situation and operating conditions of the new energy power generation farm 410, and monitor the operating conditions of the new energy power generation system 400.

[0062] In some embodiments, the new energy power generation farm 410 adopts a wind power farm, including a number of wind turbines 411, a wind farm collector system 412, and a wind farm control system 413. Each wind turbine 411 is connected to the wind farm collector system 412 through a power cable 440. The wind farm collector system 412 is connected to the power cables in each energy storage working unit 100 of the energy storage device 420 through a power cable 440. Each power cable is first connected to the boost control device 450 through a power cable 440 and then connected to the main power grid 500 through a power cable 440. The wind farm collector system 412 is connected to the wind farm control system 413 through a control cable 200, and the wind farm control system 413 is connected to the main control system 430 through a control cable 200.

[0063] Furthermore, the total control system 430 and the sub-control system 300 in the energy storage device 420 are basically the same in composition. The difference is that the total control system 430 does not have a sensing unit, which will not be elaborated here.

[0064] The operation process of the new energy power generation system provided in the embodiments of the second aspect of the present disclosure is described as follows:

[0065] During energy storage operation: The wind farm control system 413 sends the value that the wind farm power generation can reach and the scale of power generation in a future period (such as the next 4 hours) to the total control system 430 in real time. The total control system 430 sends an energy storage operation instruction to an energy storage device 420 that is not at full-load energy storage through the second operation controller therein. The first operation controller 320 of the sub-control system 300 of the energy storage device 420 starts the corresponding number of energy storage working units 100 in the energy storage device 420. At the same time, the total control system 430 sends an instruction to the wind farm control system 413 to control the wind farm collector system 412 to connect to the power cable 440. The energy storage device 420 that receives the energy storage operation instruction starts energy storage. During the energy storage operation process, the second operation controller of the total control system 430 obtains various data of the energy storage device 420 and the wind power farm in real time through the first communication interface circuit 360 and issues control instructions, obtains the real-time status of the energy storage device 420 and the wind power farm through the first monitoring unit 350, and issues control instructions through the first safety protection unit 340 to ensure the safety of personnel, equipment, and facilities in the energy storage device 420 and the wind power farm. When the energy storage device 420 reaches full-load energy storage, the total control system 430 sends an instruction to the sub-control system 300 to end the current energy storage operation of the energy storage device 420, and sends an energy storage operation instruction to an energy storage device 420 that has completed energy release again. The first operation controller 320 of the sub-control system 300 of the energy storage device 420 that receives the energy storage operation instruction starts the corresponding number of energy storage working units 100 in the energy storage device 420. When the power generation value of the wind power farm cannot meet the start-up power of any energy storage working unit 100 in the energy storage device 420, the total control system 430 sends an instruction to the wind farm control system 413 to control the wind power collector system 412 to cut off the power cable 440. At the same time, the total control system 430 issues an instruction to the sub-control system 300 of the energy storage device 420 that is performing energy storage operation to shut down the energy storage working unit 100 that is executing the energy storage operation.

[0066] During the energy release operation: The total control system 430 preferentially sends the energy release demand instruction of the main power grid 500 to a certain energy storage device 420 that is already at full load energy storage. This energy storage device 420 starts the energy release operation. The first operation controller 320 of its sub-control system 300 connects the power cable, and the corresponding energy storage working unit 100 starts the energy release operation. During the energy release operation, the total control system 430 obtains various data of this energy storage device 420 and the wind farm in real time through the first communication interface circuit 360 and issues control instructions, obtains the real-time status of the energy storage device 420 and the wind farm through the first monitoring unit 350, and issues safety control instructions through the first safety protection unit 340 to ensure the safety of the personnel, equipment, and facilities in the energy storage device 420 and the wind farm. It connects to the main power grid 500 through the boost control device 450. The boost control device 450 is responsible for raising the voltage of the new energy power generation system to a voltage value acceptable to the main power grid 500 until the energy release ends. When the energy release of this energy storage device 420 ends, the total control system 430 sends the current energy release demand instruction of the main power grid 500 to another energy storage device 420 that is already at full load energy storage. The new energy power generation system continues to supply power to the main power grid 500 until all the energy storage devices 420 of the new energy power generation system 400 can no longer meet the power supply demand of the main power grid 500. The total control system 430 controls the boost control device 450 to disconnect the power cable 440 between it and the main power grid 500.

[0067] There is at least one wind farm (or photovoltaic power generation farm, which is similar to the wind farm in the layout and function of this power generation system) in the new energy power generation system 400, equipped with 3 or more, even 24 energy storage devices 420. Each energy storage device can at least meet the energy storage demand for the wind farm (or photovoltaic power generation farm) to generate electricity at the rated power for 2 hours. The new energy power generation system 400 can solve the problems of harmonic interference and unstable output of new energy power generation to the main power grid caused by natural reasons.

[0068] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0069] Although the embodiments of the present disclosure have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present disclosure. The scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. A constant pressure energy storage device, characterized in that, It includes a sub-control system and multiple energy storage working units, and each energy storage working unit is respectively connected to the sub-control system through a control cable; The energy storage working unit includes a liquid storage tank, a hydraulic unit, an energy storage mechanism, and a pneumatic pressure regulating mechanism that are sequentially connected through a pipeline provided with a valve. The hydraulic unit is also connected to the power cable of the new energy power generation system through a power cable; the liquid storage tank stores a working liquid, and above the liquid level is a gas with a constant first pressure; the energy storage mechanism and the pneumatic pressure regulating mechanism respectively contain a working liquid and a dissolution liquid, and above the liquid level in the energy storage mechanism is a working gas with a second pressure, the second pressure is higher than the first pressure, and the solubility of the working gas in the working liquid and the dissolution liquid is different. When the pressure of the working gas in the energy storage mechanism has a continuous change trend, the dissolution amount of the working gas in the dissolution liquid is changed through the pneumatic pressure regulating mechanism, and under the action of the hydraulic unit, the working liquid circulates between the energy storage mechanism and the liquid storage tank, so that the working gas in the energy storage mechanism is maintained at a second pressure higher than the first pressure to achieve energy storage and energy release; The sub-control system is used to turn on or off the corresponding number of the energy storage working units according to the energy storage or energy release capacity requirements of the total control system of the new energy power generation system, control and monitor the equipment status in each energy storage working unit, transmit the status and parameters of the energy storage device to the total control system at any time, and regulate the energy storage device according to the instructions issued by the total control system; The working gas is selected as a single gas or a mixed gas that is less soluble in the working liquid at normal temperature, more soluble in the dissolution liquid, and does not undergo a phase change within a set working pressure range; when the working gas dissolves in the working liquid, a chemical reaction will occur with the working liquid, and a flexible diaphragm needs to be provided between the working gas and the working liquid; the dissolution liquid does not produce an obvious thermal effect when dissolving the working gas; The energy storage mechanism includes a sealed working tank that contains the working liquid and the working gas. The bottom and top of the working tank are respectively provided with a first interface and a second interface; the pneumatic pressure regulating mechanism includes a sealed regulating tank and a gas-liquid mixer and a gas-liquid separator installed on the regulating tank. The bottom and top of the regulating tank are respectively provided with a third interface and a fourth interface. The regulating tank contains a dissolution liquid, and the second interface is respectively connected to the third interface and the fourth interface through pipelines provided with corresponding valves; the liquid storage tank adopts a sealed tank or a tank with its top communicating with the atmosphere.

2. The energy storage device according to claim 1, wherein The working liquid is used as hydraulic oil.

3. The energy storage device according to claim 1, wherein, The second pressure is selected in the range of 1 MPa to 100 MPa, and the air pressure difference between the energy storage mechanism and the liquid storage tank is not less than 0.9 MPa; during energy storage, the air pressure difference between the energy storage mechanism and the pneumatic pressure regulating mechanism is controlled in the range of 0.1 MPa to 0.3 MPa.

4. The energy storage device according to claim 1, characterized in that, The hydraulic unit includes a hydraulic motor, a hydraulic pump, and a motor-generator shared by both. The motor-generator is respectively connected to the hydraulic motor and the hydraulic pump through corresponding clutches. The motor-generator is connected to the power line of the new energy power generation system through the power cable. Both ends of the hydraulic motor are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines provided with corresponding valves; both ends of the hydraulic pump are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines provided with corresponding valves.

5. The energy storage device according to claim 1, characterized in that, The gas-liquid mixer adopts any one of a stirrer, a flow deflector, and a sprayer. The stirrer and the flow deflector are arranged at the third interface, and the sprayer is arranged at the top inside the regulating tank; The gas-liquid separator adopts any one of a heater, an ultrasonic vibrator, and a membrane separator, and is arranged at the third interface.

6. The energy storage device according to claim 5, wherein When the sprayer is adopted as the gas-liquid mixer, the gas-liquid mixer further includes a mixer arranged at the third interface, a spray pipe connected between the sprayer and the third interface, and a spray liquid pump arranged on the spray pipe.

7. The energy storage device according to claim 1, wherein The sub-control system includes a first operation controller and a sensing unit, a first grid-connection control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit, and a first user interface connected thereto; the sensing unit includes a liquid level sensor for detecting the liquid level position of the working fluid in the energy storage mechanism, a pressure sensor for detecting the air pressure in the energy storage mechanism, and a rotational speed sensor for detecting the rotational speed of the hydraulic unit; when the liquid level in the energy storage mechanism is higher than the first position, the first operation controller controls the hydraulic unit to stop the working fluid from flowing from the liquid storage tank to the energy storage mechanism; when the liquid level in the energy storage mechanism is lower than the second position, the first operation controller controls the hydraulic unit to stop the working fluid from flowing from the energy storage mechanism to the liquid storage tank; when the air pressure in the energy storage mechanism continuously exceeds the second pressure, the first operation controller connects the pipeline between the top of the energy storage mechanism and the bottom of the air pressure regulating mechanism, and at the same time closes the pipeline between the top of the energy storage mechanism and the top of the air pressure regulating mechanism, and makes the working gas enter the dissolving liquid in the air pressure regulating mechanism through the air pressure regulating mechanism to be absorbed and dissolved by it, so that the air pressure in the energy storage mechanism no longer rises and remains stable; when the air pressure in the energy storage mechanism continuously is lower than the second pressure, the first operation controller connects the pipeline between the top of the air pressure regulating mechanism and the top of the energy storage mechanism, and at the same time closes the pipeline between the bottom of the air pressure regulating mechanism and the top of the energy storage mechanism, and separates the working gas absorbed by the dissolving liquid through the air pressure regulating mechanism and enters the energy storage mechanism, so that the air pressure in the energy storage mechanism no longer drops and remains stable; the first operation controller controls the rotational speed of the hydraulic unit to operate within a set rotational speed range according to the rotational speed sensor; the first operation controller senses the real-time energy storage and energy release margin of the energy storage working unit according to the liquid level sensor; the first grid-connection control unit is used to transmit the electric energy generated by the energy storage device to the main grid; the first safety protection unit is used to handle emergencies, and when the parameters exceed the preset working range, it timely shuts down the problematic energy storage working unit or even the entire energy storage device; The first monitoring unit is used to monitor the working state of the energy storage working unit in real time and transmit the data to the first operation controller, the first safety protection unit, and the first user interface; The first communication interface circuit is used to realize data communication during the working process of the energy storage device; The first user interface is used to input user instructions, change parameters, display the operation state, data, and fault conditions of the energy storage device; the first operation controller is used for the operation monitoring of the energy storage device, including start-stop control, control of each electronic device, and grid monitoring; The sub-control system controls the working modes of each energy storage working unit according to the energy storage and energy release instructions of the total control system of the new energy power generation system: when the electric energy generated by the new energy power generation site is less, the total control system instructs the sub-control system of the energy storage device to start one or a few of the energy storage working units to participate in energy storage; when the electric energy generated by the new energy power generation site is close to full load, the total control system instructs the sub-control system to start all the energy storage working units to participate in energy storage simultaneously; when the electric energy generated by the new energy power generation site is gradually increasing, the total control system instructs the sub-control system to gradually start one or more energy storage working units to participate in energy storage successively.

8. The energy storage device according to any one of claims 1 to 7, characterized in that, Its operation process includes: During energy storage operation: the sub-control system opens the corresponding number of energy storage working units according to the energy storage capacity requirement of the total control system. The sub-control system first controls the first valve, the second valve and the third valve to respectively connect the pipelines between the liquid storage tank and the hydraulic unit, between the hydraulic unit and the bottom of the energy storage mechanism, and between the top of the energy storage mechanism and the bottom of the air pressure regulating mechanism, and at the same time controls the sixth valve to close the pipeline between the top of the air pressure regulating mechanism and the top of the energy storage mechanism, and then connects the power cable to start the hydraulic unit. The working fluid enters the energy storage mechanism from the liquid storage tank, causing the liquid level in the energy storage mechanism to rise; when the air pressure in the energy storage mechanism is continuously greater than the second pressure, the sub-control system controls the air pressure regulating mechanism to make the dissolving liquid absorb and dissolve the working gas, so that the air pressure in the energy storage mechanism is maintained at the second pressure. When the liquid level in the energy storage mechanism reaches the allowable highest position, the sub-control system first disconnects the power cable, brakes the hydraulic unit, and closes all valves at the same time, so as to convert electric energy into the pressure potential energy of the working fluid and store it; if there is still surplus electric energy to be stored, the sub-control system successively opens the remaining energy storage working units until the liquid level of the working fluid in the energy storage mechanisms of all the energy storage working units in the entire energy storage device reaches the allowable highest position, realizing full-load energy storage, and the energy storage operation ends; when an unexpected situation of no energy storage capacity occurs during the energy storage process of a single or some energy storage working units, the sub-control system disconnects the power cable, brakes the hydraulic unit, and then closes all valves, and the energy storage operation is suspended; if there is still an energy storage requirement later, the energy storage working units whose energy storage operations have been suspended continue the energy storage operation until full-load energy storage of the energy storage working units is achieved, and finally full-load energy storage of the energy storage device is realized; During the energy release operation: the sub-control system turns on the corresponding number of energy storage working units according to the required energy release capacity. The sub-control system first connects the power cable to start the hydraulic unit, and at the same time controls the fourth valve, the fifth valve, and the sixth valve to connect the pipelines between the liquid storage tank and the hydraulic unit, between the hydraulic unit and the bottom of the energy storage mechanism, and between the top of the energy storage mechanism and the top of the air pressure regulating mechanism respectively, and at the same time closes the third valve. Under the action of the working air pressure, the liquid level of the working liquid in the energy storage mechanism drops. This working liquid acts on the hydraulic unit to generate electricity, and then enters the liquid storage tank, becoming a liquid with only the first pressure. As the liquid level in the energy storage mechanism drops, when the air pressure in the energy storage mechanism is lower than the second pressure, the sub-control system controls the air pressure regulating mechanism to separate the working air in the dissolved liquid and enter the energy storage mechanism, so that the air pressure in the energy storage mechanism is maintained at the second pressure. When the liquid level in the energy storage mechanism reaches the allowable lowest position, the sub-control system disconnects the power cable and brakes the hydraulic unit, and at the same time closes all valves, and the energy release of the energy storage working unit ends, thereby converting the pressure potential energy of the working liquid into electrical energy; if the energy storage device still has an energy release requirement, the sub-control system turns on the remaining corresponding number of energy storage working units until all the energy storage working units in the energy storage device achieve full-load energy release; when a single or some energy storage working units are in the process of energy release and accidentally there is a situation where energy release is not required, the sub-control system first disconnects the power cable and brakes the hydraulic unit, then closes all valves, and the energy release operation is suspended. If there is still an energy release requirement later, the energy storage working units whose energy release operations have been suspended will continue the energy release operation until the full-load energy release of the energy storage working units, and finally achieve the full-load energy release of the energy storage device.

9. A new energy power generation system, characterized in that, The new energy power generation system is a wind power or photovoltaic power generation system, including a total control system and at least one wind power or photovoltaic power generation field that supplies power to the main power grid through an energy storage device. The energy storage device adopts the energy storage device according to any one of claims 1 to 8. A boost control device is also connected between the energy storage device and the main power grid; each wind power or photovoltaic power generation field is configured with at least three such energy storage devices. The maximum rated power generation of the wind power or photovoltaic power generation field is equal to the energy storage power of one energy storage device. When the wind power or photovoltaic power generation field generates electricity, one energy storage device performs energy storage operation, one energy storage device can be put into energy release operation, and at least one energy storage device remains in a full-load energy storage state; the sub-control systems in the wind power or photovoltaic power generation field, the boost control device, and each energy storage device are all connected to the total control system through control cables. Power is transmitted between the wind power or photovoltaic power generation field, the energy storage device, and the main power grid through power cables; The total control system is used to start and stop the corresponding energy storage device according to the power generation situation and operating conditions of the wind or photovoltaic power generation field for energy storage and transmit electric energy to the main power grid, and monitor the operating conditions of the power generation system.

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