A multi-layer gravity energy storage system and energy storage method

Abstract

The present application provides a multi-layer gravity energy storage system and an energy storage method. The system includes multiple layers of storage yards for storing heavy blocks, and each layer of the storage yard is provided with a stacking unit and a transfer unit; it also includes a lifting unit, a lowering unit, and a control unit, and the control unit is connected to and controls each of the other units. The method includes inputting load data, calculating the power difference, and judging the energy storage and release requirements; calculating the product Mh of the mass and height of the heavy blocks that need to be transported; when performing energy storage or release, according to Mh, with the goal of finding the optimal path, calculating the number of heavy blocks that need to be transported and the distance that each heavy block needs to travel in each lifting unit or lowering unit; according to the calculation results, mobilize the stacking unit and the transfer unit to mobilize the required heavy blocks into the designated layer of the storage yard. Through the processing solution of the present application, the applicable range is wide, it is convenient to use, and the energy storage and release are maximally matched with the energy required by the power grid in real time.

Description

Technical Field

[0001] The present application relates to the technical field of power generation energy storage, and particularly to a multi-layer gravity energy storage system and an energy storage method. Background Art

[0002] At present, the installed capacity of fluctuating energy sources mainly based on wind energy and solar energy has been growing rapidly. Wind energy and solar energy are greatly affected by natural factors. The prominent problems are the randomness and intermittency of power generation. After large-scale access to the power grid, many problems will be brought in aspects such as power balance, power consumption, and stable control. Their power fluctuations are relatively large. If forced power regulation is carried out, it means a large amount of abandoned wind and light, posing high requirements and new challenges for the rapid and flexible regulation of the power system.

[0003] The existing power system energy storage technologies currently include pumped storage, compressed air energy storage, battery energy storage, flywheel energy storage, power-to-hydrogen energy storage, superconducting energy storage, and supercapacitor energy storage, etc. Among them, in terms of physical energy storage, the pumped storage technology has been developed most widely. Its energy storage scale and power are large, but pumped storage requires special geographical conditions, and its construction period is long, with huge initial investment. Coupled with the evaporation of the medium water, its utilization efficiency is generally only about 75%. Based on this, in recent years, gravity energy storage has developed as another important energy storage method in physical energy storage. The gravity energy storage methods that have begun to be studied currently mainly include piston-type gravity energy storage, suspended gravity energy storage, concrete block energy storage towers, mountain gravity energy storage, and buoyancy energy storage similar to the principle of gravity energy storage. The basic principle of gravity energy storage power generation is similar to that of pumped storage technology. The basic processes of energy storage and power generation are: using surplus power to lift heavy objects and store potential energy; when needed, driving a generator to generate power by releasing the potential energy of the heavy objects through conversion.

[0004] Referring to relevant literature and patents, the existing gravity energy storage methods have relatively prominent disadvantages. In the current gravity energy storage devices, the lifting devices are basically fixed at a certain horizontal height, and the distance between the upper and lower bins is fixed. In addition, the heavy objects generally have the same specifications, which leads to a step jump in the product of the mass and height of the heavy object blocks rising and falling in the energy storage system. It is difficult to match the energy used by the user side with the energy released by the energy storage system in real time, and certain obstacles are also encountered in terms of capacity expansion. Summary of the Invention

[0005] In view of this, the embodiments of the present application provide a multi-layer gravity energy storage system and an energy storage method, aiming to propose a method that can maximize the matching of the product of the mass and height of the heavy object blocks lifted or lowered with the energy storage and energy release as much as possible to make the best use of energy, and at the same time assisted by an algorithm that minimizes the moving distance of the heavy objects between layers, so that on the basis of meeting the coupling of transforming the abandoned floor into a gravity energy storage device, the heavy objects can be flexibly called.

[0006] In a first aspect, an embodiment of the present application provides a multi-layer gravity energy storage system, which includes multiple layers of yards for storing heavy blocks. In each layer of the yard, there is a stacking unit and a transfer unit. The stacking unit is used to grasp and release the heavy blocks, and the transfer unit is used to transport the heavy blocks.

[0007] The system further includes a lifting unit and a lowering unit. The lifting unit is used to lift the heavy blocks transported by the transfer unit to the yard on a specified layer for energy storage, and the lowering unit is used to lower the heavy blocks transported by the transfer unit to the yard on a specified layer for energy release.

[0008] The system further includes a control unit, which is connected to and controls each unit in the system.

[0009] According to a specific implementation manner of an embodiment of the present application, the transfer unit includes a transverse track and a transfer trolley, and the transfer trolley moves on the transverse track to transport the heavy blocks.

[0010] According to a specific implementation manner of an embodiment of the present application, the stacking unit includes a moving track and a manipulator. The manipulator slides on the moving track and is used to grasp and release the heavy blocks.

[0011] According to a specific implementation manner of an embodiment of the present application, both the lifting unit and the lowering unit include a motor-generator set, a transmission assembly, and a transport track. The transmission assembly is connected to the heavy block. In the lifting unit, the transmission assembly lifts the heavy block along the transport track under the action of the motor-generator set. In the lowering unit, the transmission assembly lowers the heavy block along the transport track under the action of the motor-generator set.

[0012] In a second aspect, an embodiment of the present application further provides an energy storage method for a multi-layer gravity energy storage system, which uses the multi-layer gravity energy storage system described in any embodiment of the first aspect. The energy storage method includes:

[0013] The control unit inputs load data, calculates the power difference, and judges the energy storage and release requirements.

[0014] Calculate the product Mh of the mass and height of the heavy blocks that need to be transported according to the power difference.

[0015] When energy storage is required, the lifting unit is mobilized for energy storage, and when energy release is required, the lowering unit is mobilized.

[0016] When performing energy storage or release, according to the Mh, with the goal of optimizing the path, calculate the number of heavy blocks that need to be transported and the distance that each heavy block needs to travel in each lifting unit or lowering unit.

[0017] The control unit mobilizes the stacking unit and the transfer unit according to the number of heavy object blocks and the distance that each heavy object block needs to travel in each lifting unit or lowering unit, and mobilizes the required heavy object blocks into the storage yard of the specified layer.

[0018] According to a specific implementation manner of an embodiment of the present application, the load data includes wind energy Pw, solar energy Pv, and the power required by the user side P. The power difference is ΔP, then ΔP = |Pw + Pv - P|;

[0019] When judging the energy release demand of the energy storage, if Pw + Pv > P, it is an energy storage demand; if Pw + Pv ≤ P, it is an energy release demand.

[0020] According to a specific implementation manner of an embodiment of the present application, when the storage yard is m layers, the number of types of heavy object blocks j = m, and the number of lifting units / lowering units i = m(m - 1) / 2.

[0021] According to a specific implementation manner of an embodiment of the present application, calculating the number of heavy object blocks that need to be transported includes calculating the types of heavy object blocks that need to be transported and the corresponding number of heavy object blocks under each type.

[0022] According to a specific implementation manner of an embodiment of the present application, in the step of calculating the number of heavy object blocks that need to be transported and the distance that each heavy object block needs to travel in each lifting unit or lowering unit with the goal of optimizing the path, the constraint conditions include: the total length of the travel of each type of heavy object block is an integer multiple of the sum of the travel distances of each type of heavy object block on each lifting unit / lowering unit, the sum of the products of each type of heavy object block and the traveled distance is equal to Mh, and there is sufficient supply and transfer volume of each type of heavy object block in each layer of the storage yard.

[0023] Beneficial effects

[0024] In the multi - layer gravity energy storage system and energy storage method in the embodiments of the present application, in the present invention, since the upper and lower bins of the traditional gravity energy storage are changed to multiple layers, modular design is realized, which is convenient for assembly and can realize the convenience of expanding the gravity energy storage; (2) In the present invention, the single - specification heavy objects of the traditional gravity energy storage are changed to multi - specification heavy objects, which can make the energy storage and energy release match the energy required by the power grid in real time to the greatest extent; (3) The present invention introduces an optimization algorithm to optimize the configuration of the types, quantities of heavy object blocks to be carried on each layer and the distances they need to travel. Description of the drawings

[0025] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0026] Figure 1 Schematic structural diagram of a multi-layer gravity energy storage system according to an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of the transfer unit of a multi-layer gravity energy storage system according to an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the stacking unit of a multi-layer gravity energy storage system according to an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of the lifting unit of a multi-layer gravity energy storage system according to an embodiment of the present invention;

[0030] Figure 5 Flowchart of the energy storage method of a multi-layer gravity energy storage system according to an embodiment of the present invention.

[0031] In the figure: 1, transfer unit; 2, horizontal track; 3, stacking unit; 4, descending unit; 5, lifting unit; 6, first-layer storage yard; 7, second-layer storage yard; 8, third-layer storage yard; 9, fourth-layer storage yard; 10, fifth-layer storage yard; 11, upward transportation track; 12, downward transportation track; 13, control unit; 14, external renewable energy power generation unit; 15, transmission chain; 16, power generation and electric integration machine; 17, heavy weight block; 18, transfer trolley; 19, manipulator; 20, moving track. Detailed implementation manners

[0032] The following will describe the embodiments of the present application in detail with reference to the accompanying drawings.

[0033] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0034] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement a device and / or practice a method. Additionally, this device can be implemented and this method can be practiced using other structures and / or functionality in addition to one or more of the aspects set forth herein.

[0035] It should also be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of this application. The drawings only show the components related to this application, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0036] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0037] In a first aspect, an embodiment of this application provides a multi-layer gravity energy storage system. This system adopts a modular design, changing the upper and lower bins of traditional gravity energy storage to multiple layers, which can be applied to abandoned buildings, abandoned wells, or desert areas, with flexible site selection and convenient use. The following refers to the Figure 1 to the Figure 4 for a detailed description of the multi-layer gravity energy storage system.

[0038] Referring to Figure 1 , the multi-layer gravity energy storage system includes multiple layers of yards for storing heavy blocks 17. In this embodiment, a five-layer yard is taken as an example, including a first-layer yard 6, a second-layer yard 7, a third-layer yard 8, a fourth-layer yard 9, and a fifth-layer yard 10. It should be explained that the yard can be set to other numbers of layers according to actual needs. Each layer of the yard is provided with a stacking unit 3 and a transfer unit 1. The stacking unit 3 is used to grasp and place the heavy block 17, and the transfer unit 1 is used to transport the heavy block 17. For example, when it is necessary to load the heavy block 17 into the transfer unit 1, the stacking unit 3 can grasp the heavy block 17 and place it into the transfer unit 1, or when it is necessary to unload the heavy block 17 in the transfer unit 1, the stacking unit 3 can grasp the heavy block 17 in the transfer unit 1 and place it into the yard. That is, the transportation of the heavy block 17 between the same layer of yards is completed through the transfer unit 1 and the stacking unit 3.

[0039] The multi-layer gravity energy storage system further includes a lifting unit 5 and a lowering unit 4. The lifting unit 5 is used to lift the heavy object block 17 transported by the transfer unit 1 to the storage yard on the designated layer for energy storage, and the lowering unit 4 is used to lower the heavy object block 17 transported by the transfer unit to the storage yard on the designated layer for energy release.

[0040] In one embodiment, there are two sets of five-layer storage yards. Referring to Figure 1 , on both sides of each set of storage yards, there is a set of lifting unit 5 and a set of lowering unit 4 respectively, that is, there are two sets of lifting unit 5 and two sets of lowering unit 4 in total.

[0041] The multi-layer gravity energy storage system further includes a control unit 13, which is connected to and controls each unit in the system. In addition, the control unit 13 is also connected to an external renewable energy power generation unit 14, such as an external photovoltaic power generation system or a wind power generation system. The control unit 13 can receive the power input by the external renewable energy power generation unit 14, and combine the power required by the user side to determine whether the multi-layer gravity energy storage system needs to release energy or store energy. The control unit 13 controls the operation of each unit in the system according to the judgment result to achieve energy release or energy storage. The specific energy storage and energy release method of this system refers to the description of the embodiment in the second aspect below.

[0042] In order to make it more convenient for the transfer unit 1 to transport the heavy object block 17, the transfer unit 1 includes a transverse track 2 and a transfer trolley 18. Referring to Figure 2 , the transfer trolley 18 moves on the transverse track 2 to complete the transportation of the heavy object block 17 within the same layer of the storage yard.

[0043] In one embodiment, the stacking unit 3 includes a moving track 20 and a manipulator 19. Referring to Figure 3 , the manipulator 19 slides on the moving track 20, and the manipulator 19 is used to grasp and release the heavy object block 17.

[0044] In another embodiment, both the lifting unit 5 and the lowering unit 4 include a generator-motor integrated machine 16, a transmission component, and a transportation track. Referring to Figure 4, the transmission assembly is connected to the heavy object block 17. For the lifting unit 5, the transportation track is set as the upward transportation track 11, and for the lowering unit 4, the transportation track is set as the downward transportation track 12. Both the upward transportation track 11 and the downward transportation track 12 cooperate with the transverse track 2 in the transfer unit 1 to receive the heavy object block 17 transported by the transfer trolley 18. In the lifting unit 5, the transmission assembly lifts the heavy object block 17 along the upward transportation track 11 under the action of the power generation and electric integration machine 16; in the lowering unit 4, the transmission assembly lowers the heavy object block 17 along the downward transportation track 12 under the action of the power generation and electric integration machine 16. During actual use, the transmission assembly can be set as a transmission chain 15 or a pulley block. In this embodiment, the transmission assembly is set as the transmission chain 15, and the movable end of the transmission chain 15 is connected to the heavy object block 17, and the transmission assembly can be adjusted according to actual conditions.

[0045] To make transportation more convenient, a lifting unit 5 and a lowering unit 4 can be respectively set in each layer of the multi-layer storage yard, as Figure 1 shown.

[0046] Second, the embodiment of the present application also provides an energy storage method for a multi-layer gravity energy storage system, which adopts the multi-layer gravity energy storage system described in any embodiment of the first aspect. The process of the energy storage method refers to Figure 5 , and specifically includes the following steps:

[0047] Step 1: The control unit inputs load data, calculates the power difference, and judges the energy storage and energy release requirements.

[0048] Specifically, the load data includes wind energy Pw, solar energy Pv, and the power required by the user side P. The power difference is ΔP. Among them, wind energy is the power input by the wind power generation system, solar energy is the power input by the photovoltaic power generation system, wind energy Pw and solar energy Pv are used as the supply side, and the power required by the user side P is generally the power demand of the power grid side. Then the calculation formula of ΔP is: ΔP = |Pw + Pv - P|; when judging the energy storage and energy release requirements, if Pw + Pv > P, it is an energy storage requirement; if Pw + Pv ≤ P, it is an energy release requirement.

[0049] Step 2: Calculate the product Mh of the mass and height of the heavy object block 17 that needs to be transported according to the power difference.

[0050] In this step, the calculation formula is: In the formula, μ1 is the transmission efficiency of the transmission assembly, μ2 is the efficiency of the power generation and electric integration machine 16, and g is the acceleration of gravity. Through the calculation formula of this step, the product Mh of the mass and height of the heavy object block 17 that needs to be transported can be calculated.

[0051] Step 3: According to the judgment result in Step 1, when energy storage is required, activate the lifting unit 5 for energy storage; when energy release is required, activate the lowering unit 4.

[0052] Step 4: When performing energy storage or energy release, based on the Mh, with the goal of optimizing the path, calculate the number of heavy object blocks to be transported and the distance that each heavy object block needs to travel in each lifting unit or lowering unit. Calculating the number of heavy object blocks to be transported includes calculating the types of heavy object blocks to be transported and the corresponding quantities of heavy object blocks under each type.

[0053] When the storage yard is m floors, the number of types of heavy object blocks j = m, and the number of lifting units / lowering units i = m(m - 1) / 2.

[0054] In this embodiment, a gravity energy storage system with a five - layer storage yard is used for description, that is, m = 5. Refer to Figure 1 , there are two groups of lifting units 5 on both sides of the storage yard, and two groups of lowering units 4 in the middle of the storage yard. Each lifting unit 5 on each side includes one from the second layer to the first layer, two from the third layer to the first and second layers respectively, three from the fourth layer to the first, second, and third layers respectively, and four from the fifth layer to the first, second, third, and fourth layers respectively. There are a total of ten devices, that is, i = 10.

[0055] Taking energy storage as an example, in order to enable the system to transfer the heavy object blocks 17 more orderly and make the work done by the heavy object blocks 17 match the energy storage demand as much as possible in real - time, a control algorithm is introduced in this embodiment. With the goal of finding the optimal path, obtain the types of heavy object blocks 17 (numbered by j, there are five types in total) that each lifting unit 5 needs to transport and the corresponding quantity n of each type ij , and the total distance L that this type of heavy object block 17 needs to be lifted j .

[0056] The control algorithm in this embodiment uses the particle swarm algorithm, which mainly includes the following steps:

[0057] Step 41: Set the initial values of particle velocity and position {n j} and {h ij}, where n j is the number of movements of each type of heavy object block 17 to be moved, and h ij is the distance that each lifting unit 5 moves for different types of heavy object blocks 17;

[0058] Step 42: Check the feasibility of the particles, that is, set the constraint conditions;

[0059] Step 43: Calculate the fitness value of the particles;

[0060] Step 44: Compare the particle fitness value and the current optimal value of the particle with the global optimal value, and update the current optimal value and the global optimal value;

[0061] Step 45: Update the weights, and update the velocity and position of the particle swarm;

[0062] Step 46: Determine whether the iteration times are reached or the error is less than the specified error. If not, restart from Step 41. If so, end the algorithm for finding the optimal path.

[0063] The above constraints mainly include: The total length of the operation of the heavy blocks 17 of each type should be an integer multiple of the sum of the running distances of the heavy blocks of each type on each device, that is:

[0064]

[0065] In the formula, h ij is the moving distance of the heavy blocks 17 of different types corresponding to each lifting unit 5. j is from 1 to 5, and i is from 1 to 10, as shown in the formulas (2) to (6) on the right side of Figure 5 . The specific formulas (2)-(6) are:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] The constraint also includes that the sum of the products of each type of heavy block and the traveled distance should be equal to the value Mh calculated in Step 2. The calculation formula is:

[0072]

[0073] In the formula, n j is the number of movements required for each type of heavy block 17, and m j is the mass of each type of heavy block 17, as shown in the formula (7) in Figure 5 .

[0074] The constraint also includes that each type of heavy block 17 on each layer should have sufficient supply and transportation volume, as shown in the formula (8) in Figure 5 , that is:

[0075] n j(1-5) ≤N j(1-5) ,

[0076] wherein, n j(1-5) is the number of heavy object blocks 17 that need to be moved in each layer of the storage yard calculated, and N j(1-5) is the number of existing heavy object blocks 17 in each layer of the storage yard.

[0077] Step 5: The control unit 13, according to the number n of the heavy object blocks j and the distance h that each heavy object block needs to travel in each lifting unit 5 or lowering unit 4 ij , mobilizes the stacking unit 3 and the transfer unit 1, cooperates with the lifting unit 5 or the lowering unit 4, and mobilizes the required heavy object blocks 17 into the storage yard of the specified layer.

[0078] For the energy storage operation, the calculated number n of the heavy object blocks j and the distance h that each heavy object block needs to travel in each lifting unit 5 ij are transmitted to the stacking unit 3, the transfer unit 1 and the lifting unit 5. The algorithm gives the number of different specifications of heavy object blocks 17 that need to be moved in the second-layer storage yard 7, the third-layer storage yard 8, the fourth-layer storage yard 9, and the fifth-layer storage yard 10. The control unit 13 uses these data to send signals to the transfer unit 1 and the stacking unit 3 of each layer. Each unit starts to find the conforming heavy object blocks 17 in the storage yard of its own layer and transports them onto the horizontal track 2. There is a transfer trolley 18 moving back and forth on the horizontal track 2 to complete the transportation. The heavy object blocks 17 are transported to the end of the horizontal track 2, and then enter the upward transportation track 11 of the lifting unit 5 for lifting. The two groups of lifting units 5 transport the heavy object blocks 17 of each layer into the specified layer according to the results of the optimization algorithm. After the heavy object blocks 17 reach the specified layer, they enter the transfer unit 1, and the transfer unit 1 distributes them into the module stacks of the corresponding specifications, and the stacking unit 3 places them. At this time, the lifting units 5 of each layer pass through the transmission chain 15 and are driven by the power generation and electric integration machine 16. At this time, the power generation and electric integration machine 16 functions as an electric motor, and uses the surplus power to lift the heavy objects and store potential energy.

[0079] In the energy release state, the working process is opposite to the above energy storage process, except that the process passes through the lowering unit 4, and the two sides of the lifting unit 5 are shut down. The power generation and electric integration machine 16 acts as a generator, and works repeatedly in this way.

[0080] It should be noted that in the above method, the five-layer storage yard is taken as an example. In an actual gravity energy storage system, the number of layers of the storage yard and the number of each unit can be set according to the usage situation and the environment, and it is not limited to those listed in the above embodiments, and the corresponding energy storage method is adjusted to achieve the maximum utilization of energy.

[0081] The large-scale and efficient gravity energy storage system described in the present invention has a simple structure, is easy to assemble, occupies a small area, has a low construction cost, a long service life, a high conversion efficiency, good reliability, and a high safety factor. It can assist the power grid to achieve smooth output, eliminate the peak-valley difference between day and night, perform peak shaving and frequency modulation, and provide reserve capacity, meet the requirements for stable and safe connection of new energy power generation to the power grid, and effectively reduce the phenomena of abandoned wind and abandoned light.

[0082] The novel gravity energy storage system for abandoned floors proposed by the present invention has a simple structure, can achieve modular design, is easy to assemble, and has flexible siting. In addition to being used in abandoned buildings, it can also be used in areas such as abandoned wells and deserts; it has a low cost, is easy to maintain, has a high energy conversion efficiency, and good reliability and stability; it can be matched with photovoltaic power generation or wind power generation systems, make full use of renewable energy, reduce the phenomena of abandoned wind and abandoned light, and at the same time can also assist in the upgrading of the energy structure, help the power grid perform peak shaving and frequency modulation.

[0083] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not depart from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A method for energy storage in a multi - layer gravity energy storage system, which uses a multi - layer gravity energy storage system, Characterized in that, The system includes multiple layers of storage yards for storing heavy blocks. In each layer of the storage yard, there are stacking units and transfer units. The stacking units are used to grasp and place the heavy blocks, and the transfer units are used to transport the heavy blocks; The system also includes a lifting unit and a lowering unit. The lifting unit is used to lift the heavy blocks transported by the transfer unit to the storage yard of the designated layer for energy storage, and the lowering unit is used to lower the heavy blocks transported by the transfer unit to the storage yard of the designated layer for energy release; The system also includes a control unit, which is connected to and controls each unit in the system; The energy storage method includes: The control unit inputs load data, calculates the power difference, and judges the energy storage and release requirements; Calculate the product Mh of the mass and height of the heavy blocks that need to be transported according to the power difference; When energy storage is required, the lifting unit is mobilized for energy storage, and when energy release is required, the lowering unit is mobilized; When performing energy storage or release, according to the Mh, with the goal of finding the optimal path through a control algorithm, calculate the number of heavy blocks that need to be transported and the distance that each heavy block needs to run in each lifting unit or lowering unit; The control unit mobilizes the stacking unit and the transfer unit according to the number of heavy blocks and the distance that each heavy block needs to run in each lifting unit or lowering unit, and mobilizes the required heavy blocks into the storage yard of the designated layer; Among them, when the storage yard has m layers, the number of types of heavy blocks j = m, and the number of lifting units / lowering units i = m(m - 1) / 2; The control algorithm uses the particle swarm algorithm, which includes the following steps: Step 41, set the initial values of the particle velocity and position {n j}, and {h ij}, where n j is the number of heavy blocks to be moved for each type, and h ij is the distance that each lifting unit moves for different types of heavy blocks; Step 42, Check the feasibility of the particles and set constraint conditions. The constraint conditions include: The total length of the operation of each type of heavy block is an integer multiple of the sum of the distances traveled by each type of heavy block on each lifting unit / lowering unit, the sum of the products of each type of heavy block and the traveled distance is equal to the Mh, and there is sufficient supply and transportation volume for each type of heavy block in each layer of the storage yard; Step 43, Calculate the particle fitness value; Step 44, Compare the particle fitness value and the current optimal value of the particle with the global optimal value, and update the current optimal value and the global optimal value; Step 45, Update the weights, and update the speed and position of the particle swarm; Step 46, Judge whether the iteration times are reached or the error is less than the specified error. If not, restart from step 41. If so, end the algorithm for finding the optimal path.

2. The energy storage method of the multi - layer gravity energy storage system according to claim 1, Characterized in that, The transfer unit includes a transverse track and a transfer trolley, and the transfer trolley moves on the transverse track to transport the heavy blocks.

3. The energy storage method of the multi - layer gravity energy storage system according to claim 1, Characterized in that, The stacking unit includes a moving track and a manipulator. The manipulator slides on the moving track and is used to grasp and place the heavy blocks.

4. The energy storage method of the multi - layer gravity energy storage system according to claim 1, It is characterized in that both the lifting unit and the lowering unit include a power generation and electric integration machine, a transmission component and a transportation track, and the transmission component is connected to the heavy object block; in the lifting unit, the transmission component lifts the heavy object block along the transportation track under the action of the power generation and electric integration machine; in the lowering unit, the transmission component lowers the heavy object block along the transportation track under the action of the power generation and electric integration machine.

5. The energy storage method of the multi-layer gravity energy storage system according to claim 4, It is characterized in that the transmission component is a transmission chain or a pulley block.

6. The energy storage method of the multi-layer gravity energy storage system according to claim 1, It is characterized in that the load data includes wind energy Pw, solar energy Pv and the power required by the user side P, and the power difference is ΔP, then ΔP = |Pw + Pv - P|; when judging the energy storage and energy release requirements, if Pw + Pv > P, it is an energy storage requirement; if Pw + Pv ≤ P, it is an energy release requirement.

7. The energy storage method of the multi-layer gravity energy storage system according to claim 1, It is characterized in that calculating the number of heavy object blocks to be transported includes calculating the types of heavy object blocks to be transported and the corresponding numbers of heavy object blocks under each type.

8. The energy storage method of the multi-layer gravity energy storage system according to claim 1, It is characterized in that in the step of calculating the number of heavy object blocks to be transported and the distance that each heavy object block needs to run in each lifting unit or lowering unit with the goal of optimizing the path, the constraint conditions include: the total length of the operation of each type of heavy object block is an integer multiple of the sum of the running distances of each type of heavy object block on each lifting unit / lowering unit, the sum of the products of each type of heavy object block and the running distance is equal to Mh, and each type of heavy object block in each layer of the storage yard has sufficient supply and transportation volume.

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