A piston cylinder energy storage system with piston rod oil drainage and piston supercharging

Abstract

The present invention discloses a piston-cylinder energy storage system with piston rod oil discharge and piston pressurization. The piston-cylinder energy storage system with piston rod oil discharge and piston pressurization proposed by the present invention, in the process of releasing energy, firstly sets a first, two-position, three-way reversing valve, so that the oil in the second inner cavity flows through the second, two-position, three-way reversing valve and is output to the hydraulic motor, and the hydraulic motor drives the generator to work to generate electricity to feed back to the power grid; after releasing for a certain period of time, the air pressure of the inert gas in the first inner cavity drops, and at this time the first, two-position, three-way reversing valve is reversed to put the second inner cavity in a pressure relief state, so that the pressure of the inert gas directly acts on the piston rod and is only used to push the piston rod to move downward, which is equivalent to increasing the pressure of the inert gas on the piston rod, thereby increasing the output pressure of the inert gas, thereby improving the efficiency of energy release in the hydraulic energy storage technology.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to a piston-cylinder energy storage system with a piston rod discharging oil and a piston pressurizing. Background Art

[0002] At present, there are two main types of relatively mature new energy storage technologies: one is hydraulic energy storage technology; the other is battery energy storage technology.

[0003] Hydropower storage technology has significant construction costs, relatively low stored energy density, and inefficient energy conversion. Electricity often requires long-distance transmission for use, and it can also cause irreversible environmental impacts in the reservoir's location. Therefore, it's unsuitable for existing power plants, offshore renewable energy power plants, or distributed energy storage applications.

[0004] Existing chemical batteries for energy storage suffer from short energy storage lifespans, high full-cycle costs, low response rates, and potential for overheating and explosion. Furthermore, the rare metals used in batteries are in limited supply, leading to significant costs for disassembly and environmental disposal after their use.

[0005] Relatively speaking, existing hydraulic energy storage technology and production processes are mature, with ample production capacity, making them easy to mass-produce and integrate. However, the drawback of existing hydraulic energy storage technology is that its energy release efficiency needs to be improved. Currently, hydraulic piston accumulators can only release one-third of their nominal power, calculated as the rated volume multiplied by the rated pressure. Summary of the Invention

[0006] The main purpose of the present invention is to provide a piston cylinder energy storage system with piston rod oil discharge and piston pressurization, which aims to solve the problem that the efficiency of energy release needs to be improved in the existing hydraulic energy storage technology.

[0007] To achieve the above object, the technical solution proposed by the present invention is:

[0008] A piston-cylinder energy storage system with piston rod oil discharge and piston pressurization comprises an air storage cylinder, a piston, a piston rod, an oil storage cylinder, a first two-position three-way reversing valve, a second two-position three-way reversing valve, a generator, a hydraulic motor, a hydraulic pump, an electric motor and an oil tank; the piston is slidingly arranged in the inner cavity of the air storage cylinder; one end of the piston rod is connected to the piston; the piston rod is slidingly passed through the air storage cylinder and forms a dynamic seal with the air storage cylinder; the other end of the piston rod is slidingly passed through the oil storage cylinder and forms a dynamic seal with the oil storage cylinder; the piston divides the internal space of the air storage cylinder into a first inner cavity and a second inner cavity; the second inner cavity is closer to the oil storage cylinder than the first inner cavity; the piston rod and the oil storage cylinder are combined to form an oil storage chamber;

[0009] The first inner cavity is filled with inert gas; the first two-position three-way reversing valve is respectively connected to the second inner cavity, the oil tank and the oil storage chamber; the second two-position three-way reversing valve is respectively connected to the inlet end of the hydraulic motor, the oil storage chamber and the outlet end of the hydraulic pump; the electric motor is driven and connected to the hydraulic pump; the inlet end of the hydraulic pump and the outlet end of the hydraulic motor are both connected to the oil tank; the hydraulic motor is driven and connected to the generator.

[0010] Preferably, it further includes a relief valve; the first two-position three-way reversing valve, the second two-position three-way reversing valve and the oil storage chamber are all connected to the relief valve.

[0011] Preferably, the electric motor is a dual-purpose motor for both electric motor and electric generator; and the generator is a dual-purpose motor for electric motor and electric generator.

[0012] Preferably, the hydraulic pump is a variable hydraulic pump and motor dual-purpose oil pump; the hydraulic motor is a variable hydraulic pump and motor dual-purpose oil pump.

[0013] Preferably, the system is arranged in the tower of the wind turbine generator set.

[0014] Preferably, the system is used to: when the wind turbine generator set has surplus power generation, the wind turbine generator set drives the electric motor to achieve energy storage; when the wind turbine generator set has insufficient power generation, the system outputs electric energy to feed back to the power grid.

[0015] Preferably, the oil storage cylinder is provided with an oil inlet and outlet communicating with the oil storage chamber; the first two-position three-way reversing valve and the second two-position three-way reversing valve are both connected to the oil inlet and outlet.

[0016] Preferably, the second two-position three-way reversing valve is provided with a stop valve.

[0017] Preferably, a variable-section supercharger is further provided at the lower end of the oil storage cylinder.

[0018] Preferably, a pressure-dividing section boost control valve is also provided at the lower end of the oil storage cylinder.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] The piston-cylinder energy storage system with piston rod oil discharge and piston pressurization proposed in the present invention, in the process of releasing energy, first sets a first, two-position, three-way reversing valve, so that the oil in the second inner chamber flows through the second, two-position, three-way reversing valve and is output to the hydraulic motor, and the hydraulic motor drives the generator to work and generate electricity to feed back to the power grid; after releasing for a certain period of time, the pressure of the inert gas in the first inner chamber drops, and at this time the first, two-position, three-way reversing valve is reversed to put the second inner chamber in a pressure relief state, so that the pressure of the inert gas all acts directly on the piston rod and is only used to push the piston rod to move downward, that is, the piston rod squeezes the oil in the oil storage chamber and discharges it, and drives the hydraulic motor to generate electricity to feed back to the power grid after flowing through the second, two-position, three-way reversing valve, which is equivalent to increasing the pressure of the inert gas on the piston rod, thereby increasing the output pressure of the inert gas, thereby improving the efficiency of energy release in the hydraulic energy storage technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 This is a structural schematic diagram of an embodiment of the piston-cylinder energy storage system with piston rod oil discharge and piston pressurization proposed by the present invention.

[0023] Description of reference numerals:

[0024] 1. Air storage cylinder; 2. Piston rod; 3. Oil storage cylinder; 4. First and second three-way reversing valve; 5. Overflow valve; 6. Second and second three-way reversing valve; 7. Generator; 8. Hydraulic motor; 9. Hydraulic pump; 10. Electric motor; 11. Fuel tank.

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0029] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0030] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The present invention provides a piston-cylinder energy storage system with a piston rod discharging oil and a piston pressurizing.

[0032] Please refer to the attached Figure 1 In one embodiment of a piston-cylinder energy storage system with piston rod oil discharge and piston pressurization proposed by the present invention, the piston-cylinder energy storage system with piston rod 2 oil discharge and piston pressurization includes an air storage cylinder 1, a piston, a piston rod 2, an oil storage cylinder 3, a first two-position three-way reversing valve 4, a second two-position three-way reversing valve 6, a generator 7, a hydraulic motor 8, a hydraulic pump 9, an electric motor 10, and an oil tank 11; the piston is slidably arranged in the inner cavity of the air storage cylinder 1; one end of the piston rod 2 is connected to the piston; the piston rod 2 is slidably arranged in the air storage cylinder 1 and forms a dynamic seal with the air storage cylinder 1; the other end of the piston rod 2 is slidably arranged in the oil storage cylinder 3 and forms a dynamic seal with the oil storage cylinder 3; the piston divides the internal space of the air storage cylinder 1 into a first inner cavity and a second inner cavity; the second inner cavity is closer to the oil storage cylinder 3 than the first inner cavity; the piston rod 2 and the oil storage cylinder 3 are combined to form an oil storage chamber. The piston rod 2 is a round rod.

[0033] The first inner cavity is filled with an inert gas (such as nitrogen); the first two-position three-way reversing valve 4 is respectively connected to the second inner cavity, the oil tank 11 and the oil storage chamber; the second two-position three-way reversing valve 6 is respectively connected to the inlet end of the hydraulic motor 8, the oil storage chamber and the outlet end of the hydraulic pump 9; the electric motor 10 is driven and connected to the hydraulic pump 9; the inlet end of the hydraulic pump 9 and the outlet end of the hydraulic motor 8 are both connected to the oil tank 11; the hydraulic motor 8 is driven and connected to the generator 7.

[0034] The working principle of this system is as follows: in the initial state, the pressure of the inert gas in the first inner cavity is low; when energy storage is required, the excess electric energy of the power grid drives the motor 10 to rotate, and the motor 10 then drives the hydraulic pump 9 to pump out the oil in the oil tank 11 through the pipeline and the second two-position three-way reversing valve 6 into the oil storage chamber, so as to push the piston rod 2 to move upward, so as to compress the inert gas in the first inner cavity to achieve energy storage; at the same time, the oil enters the second inner cavity through the first two-position three-way reversing valve 4, pushing the piston and the piston rod 2 to move upward, so as to compress the inert gas in the first inner cavity to achieve energy storage; that is, the piston can be pushed upward through two channels to compress the inert gas, thereby improving the energy storage efficiency.

[0035] When energy needs to be released, the motor 10 stops working first; in the initial stage of energy release, the pressure of the inert gas is relatively high. At this time, the second two-position three-way reversing valve 6 is reversed, and the first two-position three-way reversing valve 4 is not operated. In this state, the second inner cavity and the oil storage chamber are both connected to the oil tank 11 (specifically, the second inner cavity and the oil storage chamber are connected through the oil discharge pipe); the piston and the piston rod 2 are subjected to the pressure of the compressed inert gas on their upper surfaces and move downward to discharge the oil in the second inner cavity, and then flow through the second two-position three-way reversing valve 6 to drive the hydraulic motor 8, and the hydraulic motor 8 drives the generator 7 to generate electricity to feed back to the power grid; at the same time, the oil in the oil storage chamber will also be squeezed by the piston rod 2 and pass through the pipeline to the second two-position three-way reversing valve 6, and then pass through the second two-position three-way reversing valve 6 to drive the hydraulic motor 8, and the hydraulic motor 8 drives the generator 7 to generate electricity to feed back to the power grid.

[0036] At the later stage of energy release, that is, when the pressure of the inert gas in the first inner chamber drops to the set value; the first two-position three-way reversing valve 4 is reversed, and at this time the second inner chamber is connected to the oil tank 11, that is, the second inner chamber is now connected to the outside and is in a pressure relief state; then the pressure of the inert gas directly acts on the piston rod 2, and is only used to push the piston rod 2 downward (that is, it is only used to squeeze the oil in the oil storage chamber and discharge it to drive the hydraulic motor 8 to generate electricity), which is equivalent to increasing the pressure of the inert gas on the piston rod 2, thereby increasing the output pressure of the inert gas; after the oil is completely discharged, the first two-position three-way reversing valve 4 and the second two-position three-way reversing valve 6 are reversed again, that is, restored to the initial state, thereby preparing for the next energy storage-release process.

[0037] The piston rod oil discharge and piston pressurization piston cylinder energy storage system proposed in the present invention, in the process of releasing energy, first sets the first, two-position, three-way reversing valve 4, so that the oil in the second inner cavity flows through the second, two-position, three-way reversing valve 6 and is output to the hydraulic motor 8, and the hydraulic motor 8 drives the generator 7 to work to generate electricity to feed back to the power grid; after a certain period of release, the pressure of the inert gas in the first inner cavity drops. At this time, the first, two-position, three-way reversing valve 4 is reversed to put the second inner cavity in a pressure relief state. The pressure of the inert gas then acts directly on the piston rod 2 and is only used to push the piston rod 2 to move downward, that is, the piston rod 2 squeezes the oil in the oil storage chamber and discharges it, and drives the hydraulic motor 8 to generate electricity to feed back to the power grid after flowing through the second, two-position, three-way reversing valve 6, which is equivalent to increasing the pressure of the inert gas on the piston rod 2, thereby increasing the output pressure of the inert gas, thereby improving the efficiency of energy release in the hydraulic energy storage technology.

[0038] In addition, the piston rod oil discharge piston pressurization piston cylinder energy storage system also includes a relief valve 5; the first two-position three-way reversing valve 4, the second two-position three-way reversing valve 6 and the oil storage chamber are all connected to the relief valve 5.

[0039] Meanwhile, the electric motor 10 is a motor-generator dual-purpose motor; the generator 7 is also a motor-generator dual-purpose motor; the hydraulic pump 9 is a variable hydraulic pump-motor dual-purpose oil pump; and the hydraulic motor 8 is a variable hydraulic pump-motor dual-purpose oil pump.

[0040] Specifically, the system is installed within the tower of a wind turbine. When installed within the tower, it is used to: When the wind turbine is generating excess power, the wind turbine drives the motor 10 to store energy; when the wind turbine is generating insufficient power, the system outputs electrical energy to feed back into the grid (see above for the specific operating principle).

[0041] Furthermore, the oil reservoir 3 is provided with an oil inlet and outlet communicating with the oil storage chamber; the first, second, third, and fourth directional control valves 4 and 6 are both connected to the oil inlet and outlet. Specifically, an oil pipeline is connected to the oil inlet and outlet, and the first, second, third, and fourth directional control valves 4 and 6 are both connected to the oil pipeline.

[0042] At the same time, the second two-position three-way reversing valve 6 is provided with a stop valve. The lower end of the oil storage cylinder 3 is also provided with a variable cross-section supercharger. The lower end of the oil storage cylinder 3 is also provided with a pressure-dividing section boost control valve.

[0043] Through the above technical solution, the structure and function of the piston cylinder energy storage system with piston rod oil discharge and piston pressurization are further improved.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A piston-cylinder energy storage system with piston rod oil discharge and piston pressurization, characterized in that: The cam is connected to the hydraulic cylinder to form an oil storage chamber, and the cam is connected to the hydraulic cylinder to form an oil storage chamber. The cam is connected to the hydraulic cylinder to form an oil storage chamber. The cam is connected to the hydraulic cylinder to form an oil storage chamber. The cam is connected to the hydraulic cylinder to form an oil storage chamber. The cam is connected to the hydraulic cylinder to form an oil storage chamber. The cam is connected to the hydraulic cylinder to form an oil storage chamber. The first inner cavity is filled with inert gas; the first two-position three-way reversing valve is respectively connected to the second inner cavity, the oil tank and the oil storage chamber; the second two-position three-way reversing valve is respectively connected to the inlet end of the hydraulic motor, the oil storage chamber and the outlet end of the hydraulic pump; the electric motor is driven and connected to the hydraulic pump; the inlet end of the hydraulic pump and the outlet end of the hydraulic motor are both connected to the oil tank; the hydraulic motor is driven and connected to the generator; the system is arranged in the tower of the wind turbine generator set; the system is used for: when the wind turbine generator set has surplus power generation, the wind turbine generator set drives the electric motor to realize energy storage; when the wind turbine generator set has insufficient power generation, it outputs electrical energy to feed back to the power grid; the oil storage cylinder is provided with an oil inlet and outlet that pass through the oil storage chamber; the first two-position three-way reversing valve and the second two-position three-way reversing valve are both connected to the oil inlet and outlet; the lower end of the oil storage cylinder is also provided with a variable-section supercharger; the lower end of the oil storage cylinder is also provided with a pressure-dividing section boost control valve.

2. A piston-cylinder energy storage system with piston rod oil discharge and piston pressurization according to claim 1, characterized in that: It also includes a relief valve; the first two-position three-way reversing valve, the second two-position three-way reversing valve and the oil storage chamber are all connected to the relief valve.

3. The piston-cylinder energy storage system with piston rod oil discharge and piston pressurization according to claim 1, characterized in that: The electric motor is a dual-purpose motor for electric motor and generator; the generator is a dual-purpose motor for electric motor and generator.

4. The piston-cylinder energy storage system with piston rod oil discharge and piston pressurization according to claim 1, characterized in that: The hydraulic pump is a variable hydraulic pump and motor dual-purpose oil pump; the hydraulic motor is a variable hydraulic pump and motor dual-purpose oil pump.

5. The piston-cylinder energy storage system with piston rod oil discharge and piston pressurization according to claim 1, characterized in that: The second two-position three-way reversing valve is provided with a stop valve.

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