Constant air pressure energy storage device and new energy power generation system

Abstract

The invention provides a constant air pressure energy storage device which comprises a sub-control system and a plurality of energy storage working units connected with the sub-control system, and each energy storage working unit comprises a liquid storage tank, a hydraulic unit, an energy storage mechanism and an air pressure adjusting mechanism which are sequentially connected through a pipeline provided with a valve; working liquid and dissolving liquid are contained in the energy storage mechanism and the air pressure adjusting mechanism respectively, 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 solubility of the working gas in the dissolving liquid are different, and when the pressure of the working gas in the energy storage mechanism has a continuous change trend, the working gas is separated from the energy storage mechanism. The dissolving amount of working gas in the dissolving liquid is changed through the air pressure adjusting mechanism, the working liquid circulates between the energy storage mechanism and the liquid storage tank under the action of the hydraulic unit, the working gas in the energy storage mechanism is kept at the set pressure, and energy storage and energy release are achieved. According to the invention, heat exchange and heat storage are not needed, and compressed gas with constant air pressure is subjected to long-time, large-capacity and multi-mode energy storage and energy release.

Description

Technical Field

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

[0002] Wind and solar energy are both renewable energy sources. Since they come from nature, they will not be exhausted. 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 emission of carbon dioxide and other greenhouse gases, which helps to mitigate the impact of global warming. However, affected by natural and technical factors, wind power generation and photovoltaic power generation are intermittent, random, and poorly dispatchable, which will cause a series of power quality problems. First, when wind power generation and photovoltaic power generation are affected by weather and the output power fluctuates, it will cause voltage fluctuations on the wind farm transmission line, and then cause grid voltage fluctuations; when the output power of the wind power generation system is large, flicker will also occur. Secondly, since the output of wind power generation and photovoltaic power generation is somewhat random, as the proportion of these two new energy sources in the total power generation of the power grid continues to increase, there may be frequency fluctuations in the power grid, which will have a bad impact on the power system and its users. In addition, since wind power generation and photovoltaic power generation both use a large number of power electronic equipment, they will generate a large number of harmonics and DC components. After harmonics are injected into the power system, they will cause voltage distortion in the power grid system and affect the power quality of the entire power grid system. When the two types of renewable energy power generation account for a small proportion of the power grid, the above defects can be controlled within the allowable range through modern power electronics technology; when these two types of renewable energy power generation are connected to the grid on a large scale, they will have a great impact on the power system. The power grid must control the capacity of renewable energy power generation within a controllable range to minimize the adverse effects. This not only greatly limits the construction scale and development speed of these two types of renewable energy, but also leads to coal-fired power plants that cause great damage to the environment and account for a large proportion of carbon emissions. Still as the main power generation force. In order to ensure the smooth operation of the power grid, part of the power generation capacity of these two types of renewable energy is often abandoned in vain, so that the renewable energy power generation system cannot obtain the expected economic benefits. To this end, measures have been taken to develop and promote new energy storage technologies and supporting new energy storage power stations to reduce energy waste and improve the utilization efficiency of new energy, thereby achieving energy conservation and environmental protection. Secondly, new energy storage technologies can improve the reliability and stability of energy. Since energy storage power stations using new energy storage technologies require large capital investments, they currently play three main roles: First, balancing electricity supply and demand. Energy storage power stations can store electricity during peak electricity demand to balance electricity supply and ensure the stability of the power network, which helps reduce the risk of power outages and improve the reliability of the power system. Second, integrating renewable energy: Renewable energy such as wind and solar energy are volatile. Energy storage power stations can capture and store excess electricity to provide electricity during unstable periods. Third, frequency regulation and backup power supply. Energy storage power stations can be used as frequency regulation equipment for the power system to quickly respond to fluctuations in electricity demand.However, this cannot completely eliminate the above-mentioned adverse effects of these two types of renewable energy on the power grid. For the stability of the entire power grid and high power quality, renewable energy can only occupy a small share in the power supply. The traditional power generation method based on coal-fired power generation is still the main means of power generation because the power generation process is fully controllable and the power quality is excellent. This is contrary to the original intention of vigorously developing renewable energy.

[0003] Compressed gas energy storage is to use electric motors to do work when there is surplus electricity, use compressors to compress gas and increase pressure, and convert electrical energy into pressure potential energy; when electricity generation is required, high-pressure gas is used to drive the turbine to do work and drive the generator to rotate, thereby converting pressure potential energy into electrical energy. However, when compressing gas energy storage, heat needs to be released continuously, and when the gas is expanded to do work, heat needs to be absorbed. For this purpose, technical means such as heat exchange and heat storage are required. In actual application, it is not only time-consuming and labor-intensive, and the cost is huge, but also because the heat exchange and heat storage process will cause heat loss, 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 areas have such construction conditions. The above reasons have led to the fact that this energy storage method is not widely used. Summary of the invention

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

[0005] To this end, the present disclosure provides a constant pressure energy storage device and a new energy power generation system that do not require heat storage. The present disclosure utilizes the principle that certain gases can be dissolved in a solution and separated from the solution under certain conditions, so as to achieve energy storage and energy release without heat exchange and heat storage, and to allow compressed gas that maintains a constant pressure, and can achieve long-term, large-capacity and multiple modes of energy storage and energy release. The present 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 is 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, which solves the technical problems caused by the instability of power generation of the two new energy sources, and at the same time creates conditions for some regions to establish a power supply pattern dominated by new energy sources and explore the gradual withdrawal of coal-fired power plants from the power system.

[0006] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0007] A first aspect of the present disclosure provides a constant air pressure energy storage device, comprising a sub-control system and a plurality of energy storage working units, each energy storage working unit being connected to the sub-control system via a control cable;

[0008] The energy storage working unit comprises a liquid storage tank, a hydraulic unit, an energy storage mechanism and a gas pressure regulating mechanism which are sequentially connected through a pipeline provided with a valve, and 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 working fluid, and above the liquid level is gas with a constant first pressure; the energy storage mechanism and the gas pressure regulating mechanism contain working fluid and dissolving fluid respectively, and above the liquid level in the energy storage mechanism contains 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 fluid and the dissolving fluid is different, when the pressure of the working gas in the energy storage mechanism shows a trend of continuous change, the dissolved amount of the working gas in the dissolving fluid is changed through the gas pressure regulating mechanism, and under the action of the hydraulic unit, the working fluid is circulated 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, so as to realize energy storage and energy release;

[0009] The sub-control system is used to open or close a corresponding number of the energy storage working units according to the energy storage or release capacity requirements of the overall 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 overall control system at any time, and regulate the energy storage device according to the instructions issued by the overall control system.

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

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

[0012] In some embodiments, the hydraulic unit includes a hydraulic motor, a hydraulic pump and a generator motor shared by the two, 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, and the two ends of the hydraulic motor are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines with corresponding valves; the two ends of the hydraulic pump are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines with corresponding valves.

[0013] In some embodiments, the energy storage mechanism includes a sealed working tank, which contains the working fluid and the working gas, and the bottom and top of the working tank are respectively provided with a first interface and a second interface; 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, and the bottom and top of the regulating tank are respectively provided with a third interface and a fourth interface, the regulating tank contains a dissolved liquid, and the second interface is respectively connected to the third interface and the fourth interface through pipelines with corresponding valves; the liquid storage tank adopts a sealed tank body or a tank body connected to the atmosphere at the top.

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

[0015] The gas-liquid separator is 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 also includes a flow 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 sensor unit connected thereto, a first grid-connected control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit and a first user interface; the sensor unit includes a level sensor for detecting the position of the working fluid level in the energy storage mechanism, a pressure sensor for detecting the working gas pressure in the energy storage mechanism, and a speed sensor for detecting the speed of the hydraulic unit; when the liquid level in the energy storage mechanism is higher than a first position, the first operation controller controls the hydraulic unit to stop the working fluid from the liquid storage tank to the energy storage mechanism; when the liquid level in the energy storage mechanism is lower than a second position, the 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 is continuously higher than 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 closes the pipeline between the top of the energy storage mechanism and the top of the air pressure regulating mechanism, and allows the working gas to enter the dissolved liquid in the air pressure regulating mechanism through the air pressure regulating mechanism and 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 is continuously lower than the second air pressure, the first operation controller connects the top of the air pressure regulating mechanism and the pipeline between the top of the energy storage mechanism, and at the same time close the pipeline between the bottom of the air pressure regulating mechanism and the top of the energy storage mechanism, and separate the working gas absorbed by the dissolved liquid through the air pressure regulating mechanism and enter the energy storage mechanism, so that the air pressure in the energy storage mechanism no longer decreases and remains stable; the first operation controller controls the speed of the hydraulic unit to operate within the set speed range according to the speed sensor; the first operation controller senses the real-time energy storage and release margin of the energy storage working unit according to the liquid level sensor; the first grid-connected control unit is used to transmit the electric energy generated by the energy storage device to the main power grid; the first safety protection unit is used to deal with emergencies When the parameters exceed the preset working range, the energy storage working unit with problems, or even the entire energy storage device, is shut down in time; the first monitoring unit is used to monitor the working status 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, and display the operating status, data and fault conditions of the energy storage device; the first operation controller is used for operation monitoring of the energy storage device, including start-stop control, control of various electronic devices and power grid monitoring;

[0018] The sub-control system controls the working mode of each energy storage working unit according to the energy storage and release instructions of the overall control system of the new energy power generation system: when the power generation energy of the new energy power generation site is less, the overall control system instructs the sub-control system of the energy storage device to start a single or a few of the energy storage working units to participate in energy storage; when the power generation energy of the new energy power generation site is close to full load, the overall 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 power generation energy of the new energy power generation site gradually increases, the overall control system instructs the sub-control system to gradually start a single or multiple energy storage working units to participate in energy storage.

[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 requirements of the overall 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 gas pressure regulating mechanism. At the same time, the sixth valve is controlled to close the pipeline between the top of the gas pressure regulating mechanism and the top of the energy storage mechanism, and then the power cable is connected 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 gas pressure in the energy storage mechanism is continuously greater than the second gas pressure, the sub-control system controls the gas pressure regulating mechanism to allow the dissolved liquid to absorb and dissolve the working gas, so that the gas pressure in the energy storage mechanism is maintained at the second gas pressure. When the liquid level in the energy storage mechanism reaches the allowable pressure, the working fluid will be discharged from the liquid storage tank. When the working fluid reaches the highest position allowed, 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 the electrical energy into the pressure potential energy of the working fluid and store it; if there is still surplus electrical energy to be stored, the sub-control system successively opens the remaining energy storage working units until the entire energy storage device makes the working fluid level in the energy storage mechanism of all energy storage working units reach the highest position allowed, so as to achieve full-load energy storage and end the energy storage operation; when a single or part of the energy storage working units are in the process of energy storage and there is an unexpected lack of energy storage capacity, 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 a subsequent energy storage requirement, the energy storage working unit whose energy storage operation is suspended continues the energy storage operation until the full-load energy storage of the energy storage working unit is achieved, and finally the full-load energy storage of the energy storage device is achieved;

[0021] During energy release operation: the sub-control system opens a 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 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 top of the air pressure regulating mechanism, and at the same time closes the third valve. Under the action of the working gas pressure, the working fluid level in the energy storage mechanism drops, and the working fluid acts on the hydraulic unit to generate electricity, and then enters the liquid storage tank and becomes 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 gas in the dissolved liquid and enter the energy storage mechanism, so that the energy storage mechanism The air pressure in the mechanism is maintained at a second air pressure. When the liquid level in the energy storage mechanism reaches the lowest allowable position, the sub-control system disconnects the power cable, brakes the hydraulic unit, and closes all valves at the same time, and the energy storage working unit ends energy release, thereby converting the pressure potential energy of the working fluid into electrical energy; if the energy storage device still has energy release requirements, the sub-control system opens the remaining corresponding number of energy storage working units until all 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 unexpectedly no energy release is required, the sub-control system first disconnects the power cable, brakes the hydraulic unit, and then closes all valves to suspend the energy release operation. If there is a subsequent energy release requirement, the energy storage working unit whose energy release operation is suspended continues the energy release operation until the energy storage working unit is fully released, and finally the full-load energy release of the energy storage device is achieved.

[0022] A second aspect of the present disclosure provides a new energy power generation system, which is a wind power or photovoltaic power generation system, comprising a general control system and at least one wind power or photovoltaic power plant that supplies power to a main power grid through an energy storage device, wherein the energy storage device adopts the energy storage device according to any embodiment of the first aspect of the present disclosure, and a boost control device is further connected between the energy storage device and the main power grid; each wind power or photovoltaic power plant is configured with at least three energy storage devices, the maximum rated power generation power of the wind or photovoltaic power plant is equal to the energy storage power of one energy storage device, when the wind power or photovoltaic power plant 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 maintains a full-load energy storage state; the wind power or photovoltaic power plant, the boost control device and the sub-control systems in each energy storage device are all connected to the general control system through control cables, and power is transmitted between the wind power or photovoltaic power plant, the energy storage device and the main power grid through power cables;

[0023] The overall control system is used to open and close the corresponding energy storage device to store energy and transmit electric energy to the main power grid according to the power generation and operating conditions of the wind or photovoltaic power plant, and to monitor the operating conditions of the power generation system.

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

[0025] The present invention utilizes the principle that certain gases can dissolve in a solution and separate from the solution 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 need to release heat due to air compression during energy storage and absorb heat due to air expansion during energy release, which requires heat storage and heat exchange devices to be set up, but also avoids the problems of heat loss and reduced efficiency of energy storage devices caused by heat exchange and long-term heat preservation, thereby achieving long-term, high-efficiency, large-capacity and multi-mode energy storage and release. Specifically, the energy storage capacity of each energy storage device can store the electric energy generated by the corresponding wind farm or photovoltaic power plant at full load for a long time within a certain period of time. During the period when the output of the wind farm or photovoltaic power plant decreases or there is no output at all due to natural reasons, multiple energy storage devices will continue to generate electricity; in each energy storage device, it is possible to realize that the energy storage working units in a single or multiple energy storage devices participate in energy storage or energy release at the same time, or the energy storage working units can participate in energy storage or energy release in succession, which can not only ensure that the wind farm can still store energy in the case of light wind and changing wind speed or the photovoltaic farm can still store energy in the case of low-intensity light or changing light intensity, but also meet the main grid's requirements for the energy storage device to release electric energy flexibly. More importantly, the wind farm or photovoltaic power plant does not directly supply electricity to the main grid, but generates electricity and connects to the grid through the energy storage device, and the electric energy generated by the energy storage device remains constant, thereby solving the adverse effects of wind or solar power generation on the main grid, and creating conditions for increasing the proportion of the above two new energy power generation in the regional power grid. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0028] Figure 3 yes Figure 1 A schematic diagram of an air pressure regulating mechanism provided with a sprinkler in a single energy storage working unit in the energy storage device shown;

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

[0030] Figure 5 It is a structural schematic diagram of a new energy power generation system with the above-mentioned energy storage device provided in 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-generator 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 fluid, 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-speed sensor, 320-first operation controller, 330-first grid-connected 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 plant, 411-wind turbine generator set, 412-wind farm collection system, 413-wind farm control system, 420-energy storage device, 430-general control system, 440-power cable, 450-boost control device; 500-main power grid. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. 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] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application 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", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the basis or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and 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 "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, 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 expressly specified and limited, a first feature being “above” or “below” a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being “above”, “above”, and “above” a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] See also Figure 1 to Figure 4, a constant air 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 connected to the sub-control system 300 via 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 gas pressure regulating mechanism 120 which 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 above the liquid level is a gas with a constant first pressure. The energy storage mechanism 110 and the gas pressure regulating mechanism 120 contain the working liquid 160 and the dissolving liquid 124 respectively, and above the liquid level in the energy storage mechanism 110 contains a gas with a second pressure. The working gas 180 of the energy storage mechanism 110 is provided with a second pressure higher than the first pressure, and the solubility of the working gas 180 in the working fluid 160 and the dissolving fluid 124 is different. When the pressure of the working gas 180 in the energy storage mechanism 110 changes continuously, the dissolved amount of the working gas 180 in the dissolving fluid 124 is changed by the gas pressure regulating mechanism 120, and the working fluid 180 is circulated between the energy storage mechanism 110 and the liquid storage tank 140 under the action of the hydraulic unit 130, so that the working gas 180 in the energy storage mechanism 110 is maintained at a second pressure higher than the first pressure, so as to realize energy storage and energy release;

[0043] The sub-control system 300 is used to open or close a corresponding number of energy storage working units 100 according to the energy storage or release capacity requirements of the overall 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 the constant air pressure energy storage device to the overall control system at any time, and regulate the constant air pressure energy storage device according to the instructions issued by the overall control system.

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

[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, or even dozens, to achieve complete absorption of renewable energy power generation, and to continue to provide electrical energy to the power system when the renewable energy power plant is unable to generate electricity due to natural reasons.

[0046] In some embodiments, see Figure 2 The hydraulic unit 130 includes a hydraulic motor 131, a hydraulic pump 133 and a generator motor 132 shared by the two, 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 generator motor 132 is connected to the hydraulic motor 131 and the hydraulic pump 133 through two clutches respectively, and the generator motor 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 selected to be connected to the generator motor 132 and is in a running state; specifically, when the energy storage working unit 100 participates in energy storage operation, the clutch between the hydraulic pump 133 and the generator motor 132 is connected through the sub-control system 300, and the clutch between the hydraulic motor 131 and the generator motor 132 is disconnected; when the energy storage working unit 100 participates in energy release operation, the clutch between the hydraulic pump 133 and the generator motor 132 is disconnected through the sub-control system 300, and the clutch between the hydraulic motor 131 and the generator motor 132 is connected.

[0047] See also 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, and the lower and upper parts of the working tank 111 contain working liquid 160 and working gas 180 respectively. The air pressure regulating mechanism 120 includes a sealed regulating tank 121 and 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, and the regulating tank 121 contains dissolved liquid 124; the gas-liquid mixer 122 is installed at the third interface c and / or the fourth interface d, and is used to ensure that the working gas 180 discharged from the working tank 111 is absorbed by the dissolved liquid 124 in the regulating tank 121; the gas-liquid separator 123 is installed at the third interface c, and is used to separate the working gas 180 absorbed by the dissolved liquid 124 from the dissolved liquid 124, and discharge the regulating tank 121 from the fourth interface d and then enter the upper part of the working tank 111 from the second interface b. The liquid storage tank 140 is a sealed tank or a tank whose top is connected to the atmosphere.

[0048] Furthermore, the working fluid 160 is any liquid that can be used as hydraulic oil, and the working gas 180 should be difficult to dissolve in the working fluid 160 at room temperature, easy to dissolve in the dissolving fluid 124, and no phase change (gas to liquid or liquid to gas) occurs within the set working pressure range. A single gas or a mixed gas can be used. The dissolving fluid 124 is required to produce no obvious thermal effect when dissolving the working gas 180. The common dissolving fluid 124 corresponds to the soluble components of the working gas 180: water corresponds to carbon dioxide gas, and fluorinated carbon liquid corresponds to oxygen or carbon dioxide gas. If the working gas 180 dissolves in the working fluid 160 or can react chemically 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, i.e., the second pressure, should be selected within the range of 1MPa to 100MPa and must meet the above requirements. In order to ensure that the hydraulic unit 130 has a high efficiency, the pressure difference between the working gas 180 in the working tank 111 and the liquid storage tank 140 is not less than 0.9MPa; during energy storage, in order to ensure that the working gas 180 can smoothly enter the regulating tank 121, the working gas 180 in the working tank 111 and the working gas 180 in the regulating tank 121 should have a pressure difference, and the atmospheric pressure difference is controlled within the range of 0.1MPa to 0.3MPa. The working gas 180 of this embodiment is preferably a working gas with a pressure value of 30MPa after carbon dioxide gas and nitrogen are mixed in a ratio of 2:1, and water is preferably used as the dissolving liquid 124. The carbon dioxide in the working gas 180 can be partially dissolved in the water with a higher pressure through the gas-liquid mixer 122. The use of a mixed gas of carbon dioxide gas and nitrogen is because nitrogen is difficult to dissolve in water, which can avoid the pressure drop of the working gas above the regulating tank 121 caused by the use of a single carbon dioxide gas. The working gas is completely dissolved in water, which affects the subsequent energy release operation.

[0049] Furthermore, the liquid level of the working fluid 160 in the working tank 111 has an allowable maximum position and a minimum position, and when the liquid level of the working fluid 160 is between the allowable maximum position and the minimum position, the energy storage working unit 100 can store or release energy normally. Assume that the allowable maximum position of the liquid level of the working fluid 160 in the working tank 111 is the first position, and the allowable minimum position is the second position, which respectively correspond to the energy storage working unit 100 being in the two states of full-load energy storage and full-load energy release.

[0050] Furthermore, the working tank 111, the regulating tank 121 and the liquid storage tank 140 are all vertical tanks. In order to increase the energy storage density and the pressure of the working gas, the working tank 111 and the regulating tank 121 are elongated tanks with a circular cross section.

[0051] Furthermore, the gas-liquid mixer 122 adopts any one of a stirrer, a flow guide and a sprayer, all of which are commercially available products. The stirrer and the flow guide are arranged at the third interface c at the bottom of the regulating tank 121, and the flow guide is a mechanism for introducing the working gas 180 from the bottom of the dissolved liquid 124 in the regulating tank 121 into the dissolved liquid 124 in the form of fine bubbles. Figure 3 The sprayer 122a is arranged at the top of 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 also 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, so as to enhance the dissolution effect of the dissolved liquid 124 on the working gas 180.

[0052] Furthermore, the gas-liquid separator 123 uses any one of a heater (heating temperature does not exceed 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 heating, vibration or membrane selectivity. The gas-liquid separator 123 of this embodiment is preferably an ultrasonic vibrator.

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

[0054] Optionally, maintenance pipes 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 the maintenance pipe to facilitate the exhaustion of the working gas 180 therein when inspecting the energy storage mechanism 110 and the air pressure regulating mechanism 120. The seventh valve 157 is in a normally closed state and is only opened during maintenance.

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

[0056] In some embodiments, see Figure 2 , Figure 4The sub-control system 300 includes a first operation controller 320 and a sensor unit 310, a first grid-connected 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 sensor unit 310 includes a liquid level sensor 311 for detecting the liquid level 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, and a speed sensor 313 for measuring the pressure difference and change between the two tanks and for detecting the speed of the generator 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. 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 an 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 a closed state. When the liquid level of the working fluid 160 in the energy storage mechanism 110 reaches the first upper position, the first operation controller 320 controls the hydraulic pump 133 to stop, and at the same time, the first valve to the sixth valve are all in a closed state, and the energy storage working unit 100 stops storing energy; in 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 an 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 a closed state. When the storage When the liquid level of the working fluid 160 in the energy 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, the first valve to the sixth valve are all in a closed state, and the energy storage working unit 100 stops releasing energy; when the air pressure of 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 lower part of the regulating tank 121 The dissolved liquid 124 is then absorbed by the dissolved 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, the working gas 180 absorbed by the dissolved liquid 124 is separated 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 speed of the generator motor 132 detected by the speed sensor 313 exceeds the set speed range, the first operation controller 320 controls the excitation current voltage of the generator motor 132 so that the speed of the generator motor 132 runs within the set speed range to ensure that the generator motor does not exceed the specified working range under the working load or the power generation. The first grid-connected control unit 330 is used to transmit the electric energy generated by the energy storage device to the main power grid. The first safety protection unit 340 is used to deal with emergencies. When the parameters exceed the preset working range, the energy storage working unit 100 with problems is promptly shut down, 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 operating 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 various electronic devices and power grid monitoring. ;

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

[0058] During energy storage operation: the sub-control system 300 opens a corresponding number of energy storage working units 100 according to the energy storage capacity requirements of the overall control system. The sub-control system 300 first controls the first valve 151, the second valve 152, and the third valve 153 to respectively connect the pipeline 170 from the liquid storage tank 140 to the hydraulic pump 133, the hydraulic pump 133 to the working tank 111, and the upper part of the working tank 111 and the lower part of the regulating tank 121. At the same time, the sixth valve 156 is controlled to close the connecting pipeline 170 between the upper part of the regulating tank 121 and the upper part of the working tank 111, and then the power cable is connected to start The generator motor 132 is driven, and the clutch is controlled to connect the generator motor 132 with 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, so that the liquid level in the working tank 111 rises; when the air pressure in the upper part of the working tank 111 is greater than the air pressure above the regulating tank 121 for a period of time and higher than the set air pressure, the working gas 180 is absorbed and dissolved by the gas-liquid mixer 122 in the regulating tank 121, so that the air pressure in the working tank 111 remains basically constant. When the liquid level of the working fluid 160 reaches the upper part of the working tank 111, the working gas 180 is adjusted to the working pressure of the working tank 111. When the working fluid reaches the first position (the highest position allowed by the working fluid level), the sub-control system 300 first disconnects the power cable, brakes the generator motor 132, and closes the first valve 151, the second valve 152, and the third valve 153 at the same time, so as to convert the electrical energy into the pressure potential energy of the working fluid 160 and store it; if there is still surplus electrical energy to be stored, the sub-control system 300 successively opens the remaining energy storage working units 100 until the entire energy storage device raises the liquid level of the working fluid 160 in all energy storage working units to the first position at the top of each working tank 111. When the energy storage unit 100 is in the first position, full-load energy storage is achieved and the energy storage operation is completed; when a single or part of the energy storage working unit 100 is in the energy storage process and there is no energy storage capacity unexpectedly, the sub-control system 300 disconnects the power cable, brakes the generator motor 132, and then closes the first valve 151, the second valve 152 and the third valve 153, and the energy storage operation is suspended. If there is a subsequent energy storage requirement, the energy storage working unit 100 whose energy storage operation is suspended continues the energy storage operation until the full-load energy storage of the energy storage working unit 100 is achieved, and finally the full-load energy storage of the energy storage device is achieved;

[0059] During energy release operation: the sub-control system 300 opens a corresponding number of energy storage working units 100 according to the required energy release capacity. The sub-control system 300 first connects the generator motor 132 to the hydraulic motor 131 through the clutch, and then connects the power cable to start the generator motor 132. At the same time, the fourth valve 154, the fifth valve 155 and the sixth valve 156 are controlled 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 from the top of the working tank 111 to the top of the regulating tank 121, respectively, and ensure that the third valve 153 is in a closed state. When the working gas 180 Under the action of pressure, the liquid level of the working fluid 160 in the working tank 111 drops, and the working fluid 160 with a relatively high pressure acts on the hydraulic motor 131 to drive the generator motor 132 to rotate and generate electricity. The working fluid 160 with a relatively high pressure enters the liquid storage tank 140 after acting on the hydraulic motor 131, 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, the air pressure at 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 make the liquid The working gas 180 in the electrolyte 124 is separated and enters 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 decreases and remains constant. When the liquid level of the working fluid 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 generator motor 132, and closes the fourth valve 154, the fifth valve 155 and the sixth valve 156 at the same time, and the energy storage working unit 100 ends the energy release, thereby converting the pressure potential energy of the working fluid 160 into electrical energy; if the energy storage device still has energy release requirements, the sub-control system 300 opens the remaining phases. The corresponding number of energy storage working units 100 is connected until the entire energy storage device releases energy at full load from all the energy storage working units 100; when a single or part of the energy storage working units 100 are releasing energy and unexpectedly no energy release is required, the sub-control system 300 first disconnects the power cable and brakes the generator motor 132, and then closes the fourth valve 154, the fifth valve 155 and the sixth valve 156, and the energy release operation is suspended. If there is a subsequent energy release requirement, the energy storage working unit 100 whose energy release operation is suspended continues the energy release operation until the energy storage working unit 100 releases energy at full load, thereby finally achieving full load energy release of the energy storage device.

[0060] It can be understood that the principle that the working gas 180 can be dissolved in the dissolving liquid 124 but cannot (or is difficult to) be dissolved in the working liquid 160 eliminates the need to set up heat storage equipment. Also, since there is no heat energy loss during energy storage and release, the efficiency of the energy storage device is improved and long-term energy storage is achieved.

[0061] See also Figure 5The second aspect of the present disclosure provides a new energy power generation system 400, including a general control system 430 and at least one new energy power generation field 410 ( Figure 5 The energy storage device 420 adopts the constant pressure 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 field 410 is equipped with at least three or more energy storage devices 420. To ensure long-term energy storage and energy release, the number of energy storage devices 420 is 3 to 36, so as to ensure that the new energy power field cannot generate electricity due to natural reasons and continue to provide electricity to the main power grid 500. The maximum rated power generation power of the new energy power field 410 is equal to the energy storage power of one energy storage device 420. When the new energy power field 410 generates electricity, there is only one energy storage device 420 in the energy storage state, that is, it is performing energy storage operations (to avoid the new energy power field tripping due to excessive load). The invention relates to a power supply system 400, wherein the power supply system 400 is a power supply system 410, a power supply system 420 is a power supply system 420, and a power supply system 420 is a power supply system 430. The power supply system 430 is a power supply system 430, wherein the power supply system 43 ...

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

[0063] Furthermore, the structure of the overall control system 430 is basically the same as that of the sub-control system 300 in the energy storage device 420, except that the overall control system 430 is not provided with a sensor unit, which will not be described in detail here.

[0064] The operation process of the new energy power generation system provided by the second embodiment of the present disclosure is now described as follows:

[0065] During energy storage operation: the wind farm control system 413 sends the value of the wind farm power generation capacity and the power generation scale in the future (such as the next 4 hours) to the general control system 430 in real time. The general control system 430 sends an energy storage operation instruction to a certain energy storage device 420 that is not in 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 general control system 430 sends instructions to the wind farm control system 413. The wind farm power collection system 412 is controlled to connect the power cable 440, and the energy storage device 420 that receives the energy storage operation instruction starts to store energy. During the energy storage operation, the second operation controller of the general control system 430 obtains various data of the 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 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 farm. When the energy storage device 420 reaches full load energy storage, the general control system 430 issues an instruction to the sub-control system 300 to end the current energy storage operation of the energy storage device, and issues an energy storage operation instruction again to a certain energy storage device 420 that has released energy, and 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 farm cannot meet the starting power of any energy storage working unit 100 in the energy storage device 420, the main control system 430 sends a command to the wind farm control system 413 to control the wind power collection system 412 to cut off the power cable 440. At the same time, the main control system 430 sends a command 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 performing energy storage operation.

[0066] During the energy release operation: the general control system 430 sends the energy release demand instruction of the main power grid 500 to a certain energy storage device 420 that has stored energy at full load in priority. The energy storage device 420 starts the energy release operation, and 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 general control system 430 obtains various data of the 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 personnel, equipment and facilities in the energy storage device 420 and the wind farm, and connects to the main power grid 500 through the boost control device 450. The boost control device 450 is responsible for increasing the voltage of the new energy power generation system to a voltage value acceptable to the main power grid 500 until the energy release is completed. When the energy storage device 420 finishes releasing energy, the overall control system 430 sends the current energy release demand instruction of the main grid 500 to another energy storage device 420 that has stored energy at full load, and the new energy power generation system continues to transmit electric energy to the main 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 grid 500. The overall control system 430 controls the boost control device 450 to disconnect the power cable 440 between the main grid 500 and the main grid 500.

[0067] The new energy power generation system 400 has at least one wind farm (or photovoltaic farm, which has a similar layout and function to the wind farm in the power generation system), equipped with 3 or more, or even 24 energy storage devices 420, each of which can at least meet the energy storage needs of the wind farm (or photovoltaic farm) for 2 hours of power generation at rated power. The new energy power generation system 400 can solve the problem of harmonic interference and unstable output of the main power grid caused by natural causes.

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

[0069] Although embodiments of the present disclosure have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A constant air pressure energy storage device, characterized in that: It includes a sub-control system and a plurality of energy storage working units, each energy storage working unit is connected to the sub-control system via a control cable; The energy storage working unit comprises a liquid storage tank, a hydraulic unit, an energy storage mechanism and a gas pressure regulating mechanism which are sequentially connected through a pipeline provided with a valve, and 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 working fluid, and above the liquid level is gas with a constant first pressure; the energy storage mechanism and the gas pressure regulating mechanism contain working fluid and dissolving fluid respectively, and above the liquid level in the energy storage mechanism contains 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 fluid and the dissolving fluid is different, when the pressure of the working gas in the energy storage mechanism shows a trend of continuous change, the dissolved amount of the working gas in the dissolving fluid is changed through the gas pressure regulating mechanism, and under the action of the hydraulic unit, the working fluid is circulated 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, so as to realize energy storage and energy release; The sub-control system is used to open or close a corresponding number of the energy storage working units according to the energy storage or release capacity requirements of the overall 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 overall control system at any time, and regulate the energy storage device according to the instructions issued by the overall control system.

2. The energy storage device according to claim 1, characterized in that: The working fluid is used as hydraulic oil, and the working gas is selected to be a single gas or a mixed gas that is difficult to dissolve in the working fluid at room temperature, easily dissolves in the solvent, and does not undergo phase change within a set working pressure range; when the working gas dissolves in the working fluid or reacts chemically with the working fluid, a flexible diaphragm needs to be set between the working gas and the working fluid; the solvent does not produce obvious thermal effect when dissolving the working gas.

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

4. The energy storage device according to claim 1, characterized in that: The hydraulic unit includes a hydraulic motor, a hydraulic pump and a generator motor shared by the two. 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. The two ends of the hydraulic motor are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines with corresponding valves; the two ends of the hydraulic pump are respectively connected to the liquid storage tank and the energy storage mechanism through pipelines with corresponding valves.

5. The energy storage device according to claim 1, characterized in that: The energy storage mechanism includes a sealed working tank, which contains the working fluid and the working gas, and the bottom and top of the working tank are respectively provided with a first interface and a second interface; 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, and the bottom and top of the regulating tank are respectively provided with a third interface and a fourth interface, the regulating tank contains a dissolved 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 body or a tank body connected to the atmosphere at the top.

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

7. The energy storage device according to claim 6, characterized in that: When the gas-liquid mixer adopts the sprayer, the gas-liquid mixer also includes a flow 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.

8. The energy storage device according to claim 1, characterized in that: The sub-control system includes a first operation controller and a sensor unit connected thereto, a first grid-connected control unit, a first safety protection unit, a first monitoring unit, a first communication interface circuit and a first user interface; the sensor unit includes a liquid level sensor for detecting the position of the working fluid level in the energy storage mechanism, a pressure sensor for detecting the pressure of the working gas in the energy storage mechanism, and a speed sensor for detecting the 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 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 the energy storage mechanism to the liquid storage tank; when the air pressure in the energy storage mechanism is continuously higher than 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 stops the working fluid from flowing from the energy storage mechanism to the liquid storage tank through the air pressure regulating mechanism. The gas enters the dissolving liquid in the gas pressure regulating mechanism and is absorbed and dissolved by it, so that the gas pressure in the energy storage mechanism no longer rises and remains stable; when the gas pressure in the energy storage mechanism is continuously lower than the second gas pressure, the first operation controller connects the pipeline between the top of the gas pressure regulating mechanism and the top of the energy storage mechanism, and closes the pipeline between the bottom of the gas pressure regulating mechanism and the top of the energy storage mechanism, and separates the working gas absorbed by the dissolving liquid through the gas pressure regulating mechanism and enters the energy storage mechanism, so that the gas pressure in the energy storage mechanism no longer drops and remains stable; the first operation controller controls the speed of the hydraulic unit to operate within the set speed range according to the 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-connected control unit is used to transmit the electric energy generated by the energy storage device to the main power grid; the first safety protection unit is used to deal with emergencies. When the parameters exceed the preset working range, the problematic energy storage working unit or even the entire energy storage device is promptly closed; 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 operation of the energy storage device; The first user interface is used to input user instructions, change parameters, and display the operating status, data, and fault conditions of the energy storage device; the first operation controller is used for operating monitoring of the energy storage device, including start-stop control, control of various electronic devices, and power grid monitoring; The sub-control system controls the working mode of each energy storage working unit according to the energy storage and release instructions of the overall control system of the new energy power generation system: when the power generation energy of the new energy power generation site is less, the overall control system instructs the sub-control system of the energy storage device to start a single or a few of the energy storage working units to participate in energy storage; when the power generation energy of the new energy power generation site is close to full load, the overall 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 power generation energy of the new energy power generation site gradually increases, the overall control system instructs the sub-control system to gradually start a single or multiple energy storage working units to participate in energy storage.

9. The energy storage device according to any one of claims 1 to 8, characterized in that: Its operation process includes: During energy storage operation: the sub-control system opens a corresponding number of energy storage working units according to the energy storage capacity requirements of the overall 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 gas pressure regulating mechanism. At the same time, the sixth valve is controlled to close the pipeline between the top of the gas pressure regulating mechanism and the top of the energy storage mechanism, and then the power cable is connected 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 gas pressure in the energy storage mechanism is continuously greater than the second gas pressure, the sub-control system controls the gas pressure regulating mechanism to allow the dissolved liquid to absorb and dissolve the working gas, so that the gas pressure in the energy storage mechanism is maintained at the second gas pressure. When the liquid level in the energy storage mechanism reaches the allowable pressure, the working fluid will be discharged from the liquid storage tank. When the working fluid reaches the highest position allowed, 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 the electrical energy into the pressure potential energy of the working fluid and store it; if there is still surplus electrical energy to be stored, the sub-control system successively opens the remaining energy storage working units until the entire energy storage device makes the working fluid level in the energy storage mechanism of all energy storage working units reach the highest position allowed, so as to achieve full-load energy storage and end the energy storage operation; when a single or part of the energy storage working units are in the process of energy storage and there is an unexpected lack of energy storage capacity, 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 a subsequent energy storage requirement, the energy storage working unit whose energy storage operation is suspended continues the energy storage operation until the full-load energy storage of the energy storage working unit is achieved, and finally the full-load energy storage of the energy storage device is achieved; During energy release operation: the sub-control system opens a 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 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 top of the air pressure regulating mechanism, and at the same time closes the third valve. Under the action of the working gas pressure, the working fluid level in the energy storage mechanism drops, and the working fluid acts on the hydraulic unit to generate electricity, and then enters the liquid storage tank and becomes 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 gas in the dissolved liquid and enter the energy storage mechanism, so that the energy storage mechanism The air pressure in the mechanism is maintained at a second air pressure. When the liquid level in the energy storage mechanism reaches the lowest allowable position, the sub-control system disconnects the power cable, brakes the hydraulic unit, and closes all valves at the same time, and the energy storage working unit ends energy release, thereby converting the pressure potential energy of the working fluid into electrical energy; if the energy storage device still has energy release requirements, the sub-control system opens the remaining corresponding number of energy storage working units until all 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 unexpectedly no energy release is required, the sub-control system first disconnects the power cable, brakes the hydraulic unit, and then closes all valves to suspend the energy release operation. If there is a subsequent energy release requirement, the energy storage working unit whose energy release operation is suspended continues the energy release operation until the energy storage working unit is fully released, and finally the full-load energy release of the energy storage device is achieved.

10. A new energy power generation system, characterized in that: The new energy power generation system is a wind power or photovoltaic power generation system, comprising a general control system and at least one wind power or photovoltaic power plant that supplies power to the main power grid through an energy storage device, wherein the energy storage device adopts the energy storage device according to any one of claims 1 to 9, and a boost control device is further connected between the energy storage device and the main power grid; each wind power or photovoltaic power plant is equipped with at least three energy storage devices, the maximum rated power generation power of the wind power or photovoltaic power plant is equal to the energy storage power of one energy storage device, when the wind power or photovoltaic power plant 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 maintains full-load energy storage state; the wind power or photovoltaic power plant, the boost control device and the sub-control systems in each energy storage device are all connected to the general control system through control cables, and power is transmitted between the wind power or photovoltaic power plant, the energy storage device and the main power grid through power cables; The overall control system is used to open and close the corresponding energy storage device to store energy and transmit electric energy to the main power grid according to the power generation and operating conditions of the wind or photovoltaic power plant, and to monitor the operating conditions of the power generation system.

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