Urban underground garage type gravity energy storage system and energy storage control method thereof

Abstract

The application discloses a kind of urban underground garage type gravity energy storage systems and energy storage control method thereof, system includes underground garage unit, and inside division has parking area and shaft reserved area;Shaft energy storage unit is set in shaft reserved area and is from top to bottom through each layer of underground garage unit, shaft energy storage unit includes shaft body and the gravity block that can be lifted in shaft body;Ground park unit is set in the top of underground garage unit and shaft energy storage unit;Transmission power generation unit is connected with gravity block transmission;And control unit is electrically connected with each unit respectively.The application realizes the integration of underground energy storage and underground parking and ground park, ground zero land occupation, comprehensive efficiency is not less than 92%, system life is not less than 50 years, solid waste resource utilization rate is 30%-50%, flat degree of electric power cost is not higher than 0.28 yuan / kWh, civil engineering investment is saved by not less than 35%, construction cycle is shortened by 50%.

Description

Technical Field

[0001] This invention relates to an urban underground parking garage type gravity energy storage system and its energy storage control method, belonging to the field of gravity energy storage technology. Background Technology

[0002] With the large-scale grid connection of new energy sources such as photovoltaics and wind power, the imbalance between power supply and demand has become increasingly prominent, making energy storage technology a core support for ensuring stable grid operation and promoting the consumption of new energy. Gravity energy storage, due to its advantages such as low cost, long lifespan, environmental friendliness, and convenient operation and maintenance, has become a key development direction in the field of new energy energy storage. However, existing gravity energy storage systems mainly adopt deployment methods such as ground-level high-level reservoirs, open-pit shafts, or abandoned mines, which have the following core technical defects: (1) Poor urban adaptability: It occupies a large area, with existing ground gravity energy storage of about 2500㎡ / 1000kW. The site selection is limited, and it conflicts significantly with urban planning. The landscape coordination is poor, and it cannot be adapted to the urban core area, the surrounding area of ​​residential areas and other land-scarce scenarios, which seriously restricts its large-scale promotion in the city. (2) Insufficient overall performance: The overall efficiency of existing ground gravity energy storage systems is only about 85%, the construction period is 12-18 months, the levelized cost of electricity is about RMB 0.45 / kWh, and it does not take into account the needs of urban residents. Although lithium battery energy storage systems can achieve an overall efficiency of 85%-90% (occupying an area of ​​about 800㎡ / 1000kW), their lifespan is only 15-20 years, the levelized cost of electricity is RMB 0.4-0.6 / kWh, and there are fire safety hazards. Neither of these can meet the diverse needs of urban energy storage. (3) Unreasonable use of space: The utilization rate of underground spaces such as urban underground parking garages continues to increase, but existing underground parking garages only have a single parking function and the space value has not been fully explored; at the same time, urban ground landscape land is becoming increasingly scarce. How to achieve coordinated development of "energy storage + underground space utilization + ground landscape" has become a key problem that needs to be solved in the current urban energy storage field. In existing technologies, gravity energy storage systems have extremely low integration with urban landscapes and underground infrastructure: they either occupy a large amount of ground space, damaging the urban landscape, or require the excavation of dedicated energy storage shafts, resulting in high construction costs, long construction periods, and an inability to meet the needs of urban greening, recreation, and other public welfare requirements. Therefore, developing a gravity energy storage system that can fully utilize existing space in urban underground parking garages, integrate with surface park landscapes, and simultaneously meet the needs of energy storage, public welfare, and environmental protection has significant practical implications and extremely high industrial application value. Summary of the Invention

[0003] The purpose of this invention is to provide an energy storage control method for an urban underground parking garage-type gravity energy storage system. This invention aims to overcome the technical shortcomings of existing gravity energy storage systems, such as large land area requirements, conflicts with urban planning, poor landscape coordination, low utilization of urban underground space, and limited surface landscape land. It achieves integrated integration of "underground energy storage + underground parking + surface park," meeting the energy storage needs of core urban areas while effectively improving the utilization rate of underground space, enhancing urban landscape functions, reducing the construction cost and promotion difficulty of energy storage systems, and adapting to application scenarios in densely populated urban areas. To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a gravity energy storage system for urban underground parking garages, comprising: The underground parking garage unit is a multi-story reinforced concrete frame structure located underground. Its interior is divided into a parking area and a reserved area for vertical shafts. The reserved area for vertical shafts is integrally formed with the main structure of the underground parking garage unit, and the side walls of the reserved area for vertical shafts are equipped with reinforcement structures. A vertical shaft energy storage unit is installed in the reserved area of ​​the vertical shaft and runs through each floor of the underground garage unit from top to bottom. The vertical shaft energy storage unit includes a vertical shaft body and a gravity block that can be raised and lowered within the vertical shaft body. The ground park unit is located above the underground parking garage unit and the vertical shaft energy storage unit; A transmission-generating unit, connected to the gravity block via a transmission mechanism, is used to convert electrical energy into the mechanical energy of the gravity block; and The control unit is electrically connected to the underground parking garage unit, the vertical shaft energy storage unit, the transmission and power generation unit, and the ground park unit, respectively, and is used to control the coordinated operation of each unit. Furthermore, the reinforcement structure is a reinforced concrete reinforcement layer installed on the side wall of the reserved area of ​​the shaft, the thickness of the reinforced concrete reinforcement layer is 100-150mm, and the bearing capacity is ≥1200kN / ㎡. Furthermore, the gravity block is made of concrete and filled with solid waste aggregate, and there is a gap between the gravity block and the inner wall of the shaft body. Furthermore, the vertical shaft energy storage unit also includes a guide mechanism arranged along the inner wall of the vertical shaft body. The guide mechanism includes a guide rail and a guide slider connected to the gravity block. The guide slider is embedded in the guide rail to form a sliding fit. Furthermore, the vertical shaft energy storage unit also includes a buffer mechanism disposed at the bottom of the vertical shaft body. The buffer mechanism includes a hydraulic buffer and an energy recovery module connected to the hydraulic buffer. The energy recovery module is used to convert the hydraulic energy generated during the buffering process into electrical energy. Furthermore, the ground park unit includes a green area, a leisure walkway, and a shaft cover. The shaft cover is located in the middle of the ground park unit and corresponds to the shaft energy storage unit. The shaft cover is made of a light-transmitting material and has ventilation holes and inspection ports. The top of the shaft body is sealed to the shaft cover. Furthermore, the inner wall of the shaft body is provided with a wear-resistant layer; the bottom of the shaft body is provided with a sealing base plate; and a sealing device is provided at the connection between the underground garage unit and the shaft energy storage unit. Furthermore, the transmission power generation unit includes a winch, a gearbox, and a generator. The winch is connected to the gravity block via a wire rope, and the output end of the winch is connected to the input end of the generator via the gearbox. The transmission power generation unit also includes an electromagnetic braking device, which is electrically connected to the winch and is used to lock the winch in case of emergency stop. Furthermore, the control unit includes a PLC controller and a sensor group, the sensor group being used to collect operating parameters in real time and transmit them to the PLC controller; the control unit triggers energy storage or energy release commands based on the real-time electricity price signal of the power grid. The present invention also provides an energy storage control method for an urban underground parking garage-type gravity energy storage system based on any of the above technical solutions, comprising the following steps: Energy storage stage: During off-peak hours of the power grid, the control unit issues an energy storage command to control the transmission power generation unit to lift the gravity block and convert electrical energy into gravitational potential energy for storage. Energy release phase: During peak grid periods, the control unit issues an energy release command to control the gravity block to fall, thereby driving the transmission power generation unit to generate electricity and converting gravitational potential energy into electrical energy output; and Collaborative operation phase: The control unit performs collaborative control over the underground parking garage unit, the vertical shaft energy storage unit, the transmission power generation unit, and the ground park unit, and adjusts the power generation according to the power demand of the underground parking garage unit and the ground park unit. Compared with the prior art, the present invention has at least the following beneficial effects: This invention embeds a vertical shaft energy storage unit into the reserved area of ​​a multi-level underground parking garage, with the shaft running from top to bottom through each level of the underground garage and covered by a ground park unit, forming a three-dimensional integrated structure of "underground parking + vertical shaft energy storage + ground park". This system does not require additional ground space, achieving zero-land-occupying energy storage, reducing the land area by 100% compared to traditional ground gravity energy storage. It completely solves the technical problems of existing gravity energy storage systems having a large land area, conflicting with urban planning, and poor landscape coordination, and can be adapted to urban core areas, residential areas and other land-scarce scenarios. This invention utilizes the existing space of urban underground parking garages to set up reserved areas for vertical shafts. The reserved areas for vertical shafts are integrally formed with the main structure of the underground parking garage, eliminating the need to excavate dedicated energy storage shafts separately, thus significantly reducing earthwork excavation and construction costs. Compared with traditional ground gravity energy storage, civil engineering investment is reduced by ≥35%. Each unit is designed and constructed simultaneously, with a construction period of only 6-8 months, which is 50% shorter than traditional ground gravity energy storage, and no separate environmental impact assessment is required. The gravity block of this invention is made of cast concrete and filled with solid waste aggregates such as construction waste and slag, realizing the resource utilization of solid waste. A single 1000kW system can handle approximately 1200 tons of solid waste, with a solid waste resource utilization rate of 30%-50%, reducing cement consumption by approximately 300 tons and carbon emissions by approximately 780 tons of CO2. Simultaneously, the buffer mechanism is equipped with an energy recovery module that converts the hydraulic energy generated during the buffering process into electrical energy. The buffer energy recovery rate is stable at 80%-85%, which can improve the overall system efficiency by approximately 5%-8%, resulting in a system comprehensive efficiency ≥92%. This invention features a guiding mechanism for precise guidance of the gravity block, with an anti-sway amplitude ≤8mm; an electromagnetic braking device with an emergency stop response time ≤0.5s; a shaft body bearing capacity ≥1200kN / ㎡ and seismic fortification intensity of 8 degrees; an underground garage floor slab with a permeability grade of P8 and a double sealing device at the connection with the shaft, controlling the humidity of the underground space to ≤65%. The system has an availability rate of 99.2%, an annual downtime rate ≤0.3%, and a lifespan ≥50 years. This invention utilizes the peak-valley electricity price difference in the power grid to achieve arbitrage, the underground garage provides parking services to generate stable income, and the ground park enhances the living environment and land value of the surrounding area, thus realizing the coordinated development of energy storage, parking and landscaping. Attached Figure Description Figure 1 This is a plan view of the five underground floors of the system of this invention; Figure 2 This is a plan view of the second to fourth underground floors of the system of the present invention; Figure 3 This is a floor plan of the underground level of the system of the present invention; Figure 4 This is a ground park layout plan of the system of the present invention; Figure 5 This is an elevation view of the system of the present invention; Figure 6 This is a schematic diagram of the guiding mechanism of the system of the present invention; Figure 7 This is a schematic diagram of the energy storage / power generation principle of the system of the present invention; Figure 8 This is a schematic diagram of the system principle of the present invention. Attached reference numerals: 1-Underground parking garage unit, 11-Parking area, 12-Reserved area for vertical shaft, 2-Vertical shaft energy storage unit, 21-Guiding mechanism, 22-Guiding rail, 23-Guiding slider, 3-Gravity block, 4-Transmission power generation unit, 5-Buffer mechanism, 6-Green area, 7-Leisure walkway, 8-Vertical shaft cover. The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Detailed Implementation The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only for explaining the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art, based on the content described in this specification, can make various appropriate substitutions, modifications, or combinations to the technical solutions of the present invention, all of which fall within the scope of protection of the present invention. Example 1: A Gravity Energy Storage System for Urban Underground Garages This embodiment provides a specific implementation of an urban underground parking garage-type gravity energy storage system, applied to the vicinity of large urban residential areas, suitable for scenarios with dense populations, high parking demand, and high energy storage requirements. The system includes an underground parking garage unit 1, a vertical shaft energy storage unit 2, a surface park unit, a power generation unit 4, and a control unit. All units work together to achieve efficient energy storage and release, while also considering multiple functions such as parking, landscaping, and environmental protection. The specific structure of each unit is as follows: I. Underground parking garage unit 1 Underground parking garage unit 1 is a 5-story reinforced concrete frame structure, with each story having a height of 4.0m and a clear height under beams of 3.2m. The total depth of the underground parking garage (from the bottom elevation of the ground-level park unit to the bottom elevation of the parking garage floor slab) is 22.5m. The underground parking garage is constructed with C40 concrete. The frame column cross-section is 600mm × 600mm, the frame beam cross-section is 400mm × 800mm, and the floor slab thickness is 180mm. The structural design service life is 50 years, the seismic fortification category is Class C, and the seismic fortification intensity is 8 degrees. The underground parking garage is clearly divided into parking area 11 and a reserved vertical shaft area 12, both designed and constructed simultaneously. Parking area 11 contains multiple standard parking spaces (634 in this embodiment, each space measuring 2.5m × 5.3m, with a passageway width of 4.0m to meet two-way traffic requirements). Parking area 11 can be equipped with a mechanical ventilation system (a low-noise mixed-flow fan is used in this embodiment), an automatic fire suppression system (including an automatic sprinkler system, smoke detectors, and fire hydrant system in this embodiment), and an intelligent sensor lighting system (LED tubes with infrared sensor switches are used in this embodiment). The reserved area 12 of the vertical shaft is located in the central area of ​​the underground garage, avoiding the positions of the frame columns and main beams (in this embodiment, there are 18 reserved areas 12 of the vertical shaft, arranged in a matrix of 3 rows × 6 columns, with each reserved area 12 having a planar dimension of 2.6m × 2.6m and a net spacing of 8.0m between the reserved areas 12 of the vertical shaft, meeting the requirements for parking space layout and vehicle passage). The reserved area 12 of the vertical shaft is integrated with the main structure of the underground garage through steel reinforcement nesting and synchronous pouring: during the construction phase, hidden columns are set at the four corners of the reserved area 12 of the vertical shaft, and double-layer bidirectional steel mesh is set on the side walls, forming an integral load-bearing system with the steel reinforcement of the surrounding frame beams and slabs through lap splicing or mechanical connection. The sidewall of the reserved area 12 of the vertical shaft is reinforced with a reinforced concrete layer as a reinforcement structure. The reinforcement layer is connected to the sidewall of the reserved area 12 of the vertical shaft by rebar installation. The bearing capacity of the reinforcement layer in this embodiment is ≥1200kN / ㎡, which can withstand the impact load and dynamic load generated by the maximum 42t weight block 3 during lifting and falling. The underground parking garage floor slab is constructed using P8 grade impermeable concrete, 250mm thick, and reinforced. After the floor slab is completed, a 72-hour water tightness test is conducted to confirm no leakage before proceeding with subsequent construction. Drainage ditches and sump pits are installed on the floor slab surface. Vehicle entrances and exits are located at the north and south boundaries of the ground-level park unit, connecting to the surrounding municipal roads. Each entrance / exit employs a ramp structure, allowing for one-way dual-lane roads plus a pedestrian walkway. The ramp structure is constructed of poured concrete with anti-slip grooves on the surface. A grid-style green wall is installed at the ramp entrance for landscape screening (in this embodiment, the green wall uses a steel structure frame and climbing plants), harmonizing with the overall landscape style of the ground-level park unit and ensuring that the vehicle entrances and exits do not disrupt the integrity of the park landscape. After descending the ramp to the first basement level, vehicles proceed to the second to fifth basement levels via connecting slabs between the various levels. The equipment rooms are located adjacent to the reserved area 12 of the vertical shaft on both sides, one on each side of the underground garage. Cable trenches and pipeline channels are set between the equipment rooms and the reserved area 12 of the vertical shaft for the laying of cables and control lines. The equipment room floors are coated with epoxy self-leveling coating, the walls are treated with moisture-proofing, and an independent ventilation system and dehumidifier are installed to ensure that the humidity in the equipment room is ≤65%. II. Vertical Shaft Energy Storage Unit 2 Vertical shaft energy storage unit 2 is installed within the reserved area 12 of the vertical shaft. Each vertical shaft energy storage unit 2 has the same structure and can operate independently or simultaneously. The following is a detailed description using one vertical shaft energy storage unit 2 as an example. (I) Shaft Body The shaft body is integrally cast with reinforced concrete, extending from the top surface of the shaft base slab to the bottom surface of the shaft cover 8, penetrating five underground floors and all floor slabs. The shaft sidewalls are 300mm thick and reinforced. Brackets and water-stop steel plates are installed at the connections between the shaft and each floor slab to ensure reliable waterproofing at the joints. The inner wall of the shaft is equipped with a wear-resistant layer. This wear-resistant layer is made of polytetrafluoroethylene (PTFE) coating with a thickness of 4mm. Before coating construction, the inner wall of the shaft is ground and dusted, and a special primer is applied before spraying. The PTFE coating has a coefficient of friction ≤0.08, which can significantly reduce the frictional resistance during the lifting and lowering of gravity block 3, reduce energy loss, and at the same time, this material has good corrosion resistance and can adapt to the humid underground environment. A sealed base plate is installed at the bottom of the shaft. The sealed base plate is made of reinforced concrete and is 350mm thick. A plain concrete pad and an SBS modified bitumen waterproof membrane layer are installed beneath the base plate. The waterproof membrane is turned up along the sidewalls of the shaft to form a complete waterproof system. The sealed base plate is cast integrally with the sidewalls of the shaft without construction joints, ensuring no leakage channels at the connection between the base plate and the sidewalls. The load-bearing capacity of the base plate meets the impact load requirements when gravity block 3 falls. Holes are pre-drilled in the shaft body at each floor level, and reinforced concrete is installed around the holes to strengthen the structural strength at the holes. (II) Gravity Block 3 Gravity block 3 is cast using C40 concrete. In this embodiment, the external dimensions of gravity block 3 are 2.58m × 2.58m × 2.0m (length × width × height), and the weight of a single gravity block 3 is approximately 42t, with a density of 2.6t / m³. The casting mold for gravity block 3 is made of steel formwork, and it is formed in one go during casting, compacted by vibration, and cured for no less than 14 days. It can only be demolded and used after the concrete reaches the design strength. The gravity block 3 is filled with solid waste aggregate, which accounts for 40% of the volume of gravity block 3. The solid waste aggregate is selected from crushed construction waste (waste concrete, bricks, etc. generated from the demolition of buildings in this area, crushed to a particle size of 5-20mm by a jaw crusher, magnetically separated to remove iron, and then screened and graded for use). After adding the solid waste aggregate, the concrete mix proportion by weight is: cement 300kg / m³, sand 700kg / m³, natural crushed stone 500kg / m³, solid waste aggregate 480kg / m³, water 175kg / m³, and water-reducing agent 3.5kg / m³. After 28 days of compressive strength testing, the concrete strength grade reaches C42.5, meeting the C40 design requirements. The gap between gravity block 3 and the inner wall of the shaft body is 8mm (4mm on each side). This gap value has been verified by testing: when the gap is less than 5mm, gravity block 3 may get stuck during lifting due to uneven concrete surface; when the gap is greater than 12mm, the swing amplitude of gravity block 3 increases during lifting, and the force on guide mechanism 21 increases significantly. After 1000 lifting cycle tests, it has been verified that the 8mm gap can ensure smooth lifting of gravity block 3 without jamming, while the anti-sway amplitude of guide mechanism 21 is ≤6mm. Four lifting lugs are symmetrically arranged on the top of gravity block 3, located at the four corners of the top of gravity block 3. The lifting lugs are made of steel plate and are welded to the anchoring steel bars of gravity block 3 and then embedded in the concrete as a whole. In this embodiment, the safety factor of the lifting lugs is ≥5, and the rated lifting capacity of a single lifting lug is ≥20t. A 100mm thick natural rubber buffer pad is installed at the bottom of gravity block 3, which is fixedly connected to the bottom surface of gravity block 3 through a vulcanization bonding process. The function of the rubber buffer pad is that when gravity block 3 falls to the bottom of the shaft, it first contacts the hydraulic buffer, and absorbs part of the impact energy through the elastic deformation of the rubber, thus playing a primary buffering role and reducing the impact load on the hydraulic buffer. (III) Guiding Mechanism 21 The guide mechanism 21 is installed along the inner wall of the shaft body, with a total of 4 sets, located in the middle of the four side walls of the shaft body. Each set of guide mechanism 21 is continuously arranged along the height direction of the shaft body, extending from the top of the shaft to the bottom of the shaft, with a total length of 24m. Each guide mechanism 21 includes a guide rail 22 and a guide slider 23. The guide rail 22 is made of rolled alloy steel and is fixedly connected to the side wall of the shaft body by expansion bolts. The mounting surface of the guide rail 22 is leveled with shims between it and the inner wall of the shaft to ensure that the straightness error of the guide rail 22 is ≤1mm / total length. The surface of the guide rail 22 is hot-dip galvanized for corrosion protection to adapt to the humid underground environment. The guide slider 23 is welded and fixed to the gravity block 3. Each set of guide mechanisms 21 corresponds to two guide sliders 23. The guide slider 23 has a U-shaped cross-section with its opening facing the guide rail 22. The U-shaped groove is lined with an alloy wear-resistant plate. The guide slider 23 is welded to the gravity block 3 through a transition connecting plate. After assembly, the sliding gap between the guide slider 23 and the guide rail 22 is 0.5-1.0mm, and the gap is filled with water-resistant grease. Durability tests have verified that the wear of the guide rail of the guide mechanism 21 is ≤0.5mm, the wear of the slider wear plate is ≤2mm, the overall service life of the guide mechanism 21 is ≥50 years, and the measured anti-sway amplitude of the gravity block 3 during lifting is ≤6mm. (iv) Buffer mechanism 5 The buffer mechanism 5 is located at the bottom of the shaft body and fixed above the sealing base plate. It consists of a buffer base, a hydraulic buffer, and an energy recovery module. Four M24 anchor bolts are installed between the buffer base and the shaft bottom plate, and four pre-embedded steel plates are embedded on the top surface of the base for installing the hydraulic buffer. In this embodiment, there are four hydraulic buffers, evenly distributed at the four corners. Each hydraulic buffer is fixed to a pre-embedded steel plate by base bolts. The working principle of the hydraulic buffer is as follows: when the gravity block 3 falls to the bottom, the rubber buffer pad at the bottom of the gravity block 3 first contacts the piston rod of the hydraulic buffer. The piston rod is compressed and moves downward. The hydraulic oil generates damping force through the throttling orifice, converting the impact kinetic energy into heat energy. At the same time, the compression stroke of the piston rod absorbs the impact displacement. When the four hydraulic buffers work together, the total rated buffering force is 2000kN, which meets the buffering requirements of the 42t gravity block 3 at the maximum falling speed of 0.5m / s. The energy recovery module is connected to the hydraulic buffer via hydraulic pipelines. The hydraulic pipelines are made of seamless steel pipes, and the pipe fittings use compression fittings. The working pressure is ≥25MPa. The energy recovery module includes a hydraulic motor and a micro-generator. Its working principle is as follows: During the impact of the gravity block 3 on the hydraulic buffer, the high-pressure oil inside the hydraulic buffer drives the hydraulic motor to rotate through the hydraulic pipelines. The mechanical energy of the hydraulic motor is output to the micro-generator to generate electricity. The generated electrical energy is rectified and stabilized before being fed into the low-voltage side bus of the energy storage system. III. Ground Park Unit The ground park unit is located above the underground parking garage unit 1 and the vertical shaft energy storage unit 2, covering the entire ground area of ​​the underground facility. The ground park unit includes green areas 6, leisure trails 7, and manhole covers 8. Green area 6 adopts a layered planting pattern of trees, shrubs, and grasses. In this embodiment, the upper layer consists of alternating plantings of ginkgo and Chinese scholar trees, the middle layer of alternating plantings of crape myrtle and crabapple, and the lower layer of lawn and ground cover plants. The soil layer of green area 6 uses planting soil, and an impermeable membrane is installed below the soil layer. Underneath the impermeable membrane is a graded sand and gravel filter layer, and a flexible permeable pipe drainage system is installed within the filter layer to guide accumulated water to a collection pit for discharge. The function of the impermeable membrane is to prevent irrigation water and rainwater from seeping into the underground garage and vertical shaft energy storage unit 2, ensuring the safety of underground equipment. The leisure trail route 7 meanders around the green area 6 and the manhole cover 8, with seats and trash cans placed every 20 meters. The shaft cover 8 is located in the middle of the ground park unit and corresponds to the shaft energy storage unit 2. It is made of high-strength tempered laminated glass and is fixed to the reinforced concrete ring beam at the top of the shaft body by a stainless steel frame. Each shaft cover 8 is equipped with a ventilation hole and an inspection port. Each ventilation hole has a built-in stainless steel insect screen and a louvered waterproof cover to prevent rainwater and debris from entering the shaft. The inspection port has an aluminum alloy frame with sealing strips, and the inspection port cover is an openable structure. It is normally closed and locked, and is opened by maintenance personnel during maintenance. The top of the shaft body is sealed to the shaft cover plate 8. A reinforced concrete ring beam is installed on the top of the shaft body. Stainless steel connectors are pre-embedded on the top surface of the ring beam. After the stainless steel frame is connected to the ring beam, a rubber sealing strip is embedded in the gap between the frame and the ring beam, and sealant is applied to the outside. The lighting facilities use LED lights that are powered by solar energy. The lights have built-in photovoltaic panels, batteries and controllers. During the day, they are charged by the photovoltaic panels, and at night, they are powered by the energy storage system. When the power supply is insufficient, it is supplemented by the batteries. IV. Transmission and power generation unit 4 The drive-generation unit 4 is located in the equipment room of the underground parking garage unit 1. Each vertical shaft energy storage unit 2 is equipped with an independent drive-generation system, and each subsystem can operate independently or simultaneously. One drive-generation system includes: (a) Winch The winch is a variable frequency speed control winch, equipped with a frequency converter, and the winch motor is a three-phase asynchronous motor. The winch is connected to the gravity block 3 via a wire rope. One end of the wire rope is fixed to the winch drum through a wedge joint, and the other end is led out from the drum, turns vertically downward through the guide pulley at the top of the shaft, passes through the wire rope hole on the shaft cover plate 8, and finally connects to the lifting lug at the top of the gravity block 3 through a shackle. (ii) Gearbox The gearbox is a cylindrical gear reducer, which is horizontally mounted. The input shaft is connected to the winch drum shaft via a drum gear coupling, and the output shaft is connected to the generator input shaft via a flexible pin coupling. (iii) Generator The generator is a permanent magnet synchronous generator, and the generator output is connected to the energy storage converter. Compared with the asynchronous generator, the permanent magnet synchronous generator has higher power generation efficiency and a wider speed adaptation range, and can still maintain high power generation efficiency when the falling speed of gravity block 3 changes. (iv) Energy storage converter The energy storage converter has two-way rectification and inversion functions. During the energy storage stage (when gravity block 3 is lifted), it rectifies the AC power from the power grid into DC power to supply the frequency converter of the winch. During the energy release stage (when gravity block 3 falls and generates electricity), it rectifies the AC power generated by the generator and then inverts it into AC power with the same frequency and phase as the power grid, and connects it to the 10kV distribution network or steps it down to 380V for local use. (v) Electromagnetic braking device The electromagnetic braking device uses a normally closed disc brake of the power-off braking type. The brake is installed at the high-speed shaft end of the winch (i.e., the coupling position between the motor and the gearbox). The working principle of the brake is as follows: when the electromagnet is energized, the electromagnetic force overcomes the spring force, causing the brake to release and the winch to run freely; when the electromagnet is de-energized, the spring force pushes the friction pads to press against the brake disc, achieving braking. It can completely lock the winch in emergency stops to prevent the gravity block 3 from falling. (vi) Automatic lubrication system The transmission components (guide pulley bearings, winch bearings, couplings, etc.) are equipped with a centralized automatic lubrication system. The lubricating oil pump starts automatically every 2 hours. The controller of the lubrication system is connected to a PLC, which can monitor the oil pressure and oil volume at each lubrication point, and automatically alarm when blockage or insufficient oil occurs. (vii) Cable lines Waterproof and corrosion-resistant cables are used in the cable lines and are laid in dedicated cable trenches. The cable trenches are set in the reserved grooves in the floor slab or basement of the underground garage, and all cables are fitted with waterproof sealing sleeves where they pass through walls or floors. V. Control Unit The control unit is located in the equipment room on the west side and includes a PLC controller, sensor group and monitoring terminal. The PLC controller used is the Siemens S7-1500 series. The sensor group is divided into five categories according to its function: position detection, pressure detection, temperature detection, humidity detection, and vibration detection. The position sensor is a laser rangefinder sensor, installed below the guide pulley bracket at the top of the shaft. It emits a laser beam vertically downwards to measure the distance from the top of gravity block 3 to the sensor, thereby calculating the real-time position of gravity block 3 within the shaft. After real-time reading by the PLC, the lifting position and speed curve of gravity block 3 can be precisely controlled. The pressure sensor is a pressure transmitter, installed at the hydraulic line interface of the hydraulic buffer to monitor oil pressure changes in real time during the buffering process. The PLC determines the working status of the buffer based on the pressure signal and issues an alarm signal when the pressure exceeds the set threshold. The temperature sensors are platinum resistance temperature sensors, which are respectively installed on each winch motor, each gearbox, each generator, and at the ambient temperature monitoring point in the equipment room. The PLC collects the temperature values ​​at regular intervals, and automatically issues an alarm and takes measures such as reducing load or shutting down when the temperature exceeds the set threshold. Humidity sensors, specifically temperature and humidity transmitters, are located in the center of each shaft, within the equipment room, and in the center of the underground parking garage. The PLC automatically controls the operation of the dehumidifiers and ventilation system based on humidity data to ensure humidity remains ≤65%. The vibration sensors are piezoelectric accelerometers, which are installed on the middle support of the guide rail 22 in each shaft to monitor the vibration amplitude during the lifting and lowering of the gravity block 3. Under normal operation, the vibration amplitude is ≤2mm / s² (RMS value). When the vibration amplitude exceeds 8mm / s², it is judged as abnormal, and the PLC automatically reduces the operating speed of the winch; when the vibration amplitude exceeds 15mm / s², an emergency stop is immediately implemented. (iii) Monitoring terminal The monitoring terminal uses a touch screen and is installed on the control cabinet panel in the equipment room. The main function pages of the touch screen human-machine interface include: system overview (displaying the operating status of the shaft, real-time power, cumulative stored / released power, etc.), single-unit monitoring (displaying detailed parameters of a single shaft), alarm records (displaying alarm information in chronological order), historical trends (displaying historical curves of key parameters, with a storage period of ≥1 year), and parameter settings (setting operating parameters, such as lifting speed threshold, electricity price threshold, etc., requiring password access to log in). In addition, the monitoring terminal connects to the remote monitoring computer of the property management center via Ethernet, supporting remote monitoring and operation (requiring dual authentication). (iv) Control Logic The control unit triggers energy storage or release commands based on real-time grid price signals. The specific control logic is as follows: The control unit communicates with the power grid dispatching system or power trading platform via Ethernet to obtain real-time electricity price signals (sampling period ≤ 1 minute). When the electricity price is lower than the set energy storage threshold (e.g., 0.35 yuan / kWh, corresponding to the grid off-peak period, usually 23:00-07:00 the next day), the control unit automatically issues an energy storage command, sequentially starting the winches of each shaft to lift gravity block 3 at a speed of 0.4 m / s. During the lifting process, the PLC monitors the position of gravity block 3 in real time through position sensors and the operating status through vibration sensors, dynamically adjusting the output frequency and acceleration curve of the frequency converter (acceleration time 5s, deceleration time 5s) to ensure smooth acceleration and deceleration of gravity block 3. When gravity block 3 reaches the set position at the top of the shaft, the PLC automatically stops the winches and engages the electromagnetic braking device to lock the winches. When the electricity price exceeds the set energy release threshold (e.g., 0.75 yuan / kWh, corresponding to peak grid hours, typically 10:00-14:00 and 18:00-22:00), the control unit automatically issues an energy release command, sequentially releasing the gravity blocks 3 in each shaft. During release, the PLC controls the electromagnetic brake device to release (response time ≤ 0.3s), and then controls the winch to release the wire rope at a speed of 0.35m / s, causing the gravity blocks 3 to fall under their own weight. During the fall, the PLC monitors the generator speed in real time through the speed sensor (accuracy ±1rpm) at the input shaft end of the gearbox, and maintains a stable falling speed by adjusting the braking torque of the winch (controlled by the frequency converter), ensuring stable generator output frequency and voltage. When the gravity block 3 approaches the bottom of the shaft (the position sensor detects a distance ≤ 500mm from the bottom), the PLC reduces the falling speed to 0.1m / s until the gravity block 3 contacts the buffer mechanism 5, completing one full energy release process. Start-up / grid connection response time ≤ 800ms (from issuing the command to the start of the winch or the grid connection of the generator), power ramp rate ≥ 100kW / s, can quickly respond to the grid's dispatching needs. Example 2: An energy storage control method for an urban underground parking garage type gravity energy storage system. This example adopts the Xiyong system from Example 1. The energy storage control method of this system includes three stages: energy storage stage, energy release stage, and collaborative work stage. Each stage is connected in an orderly manner and works in coordination. Energy storage stage: The set time is from 23:00 to 7:00 the next day (8 hours in total, during off-peak hours for the Beijing power grid, with an electricity price of 0.32 yuan / kWh). Once the control unit detects that the real-time electricity price is lower than the energy storage threshold (0.35 yuan / kWh), it automatically issues an energy storage command, activating the winches of the 18 vertical shaft energy storage units 2. Each shaft winch lifts the corresponding gravity block 3 at a uniform speed of 0.4 m / s. The gravity block 3 moves upward along the guide mechanism 21, converting the electrical energy from the power grid into the gravitational potential energy of the gravity block 3 for storage. During the lifting process, the PLC monitors the position of gravity block 3 in real time via a laser rangefinder and the operating status via a vibration sensor. When gravity block 3 in any shaft is lifted to the set position at the top of the shaft, the PLC controls the winch of that shaft to decelerate to a stop and activates the electromagnetic brake to lock the winch. The system starts in batches to avoid impacting the power grid caused by starting 18 winches simultaneously. According to measurements, each gravity block 3 consumes an average of about 42kWh of electrical energy when lifted from the bottom to the top of the shaft (effective lifting height 22m) (including friction loss and transmission system loss, charging efficiency 94%). The total electrical energy consumption of 18 gravity blocks 3 for a single energy storage is about 756kWh, with an energy storage power of 1000kW and a single energy storage capacity of 4000kWh (calculated based on the power output of the generator at the time of release). Energy release phase: The set time is 10:00-14:00 and 18:00-22:00 (a total of 8 hours, peak hours of the Beijing power grid, electricity price 0.85 yuan / kWh). After the control unit detects that the real-time electricity price is higher than the energy release threshold (0.75 yuan / kWh), it automatically issues an energy release command to release the gravity blocks 3 in each shaft in sequence. Under its own weight, gravity block 3 falls uniformly along guide mechanism 21 at a speed of 0.35 m / s. It drives a winch via a wire rope, and the winch, after being accelerated by a gearbox, drives a generator to produce electricity. The three-phase AC power output from the generator is rectified and inverted by an energy storage converter, then stepped up to 10 kV and connected to the power grid. Simultaneously, a separate line is stepped down to 380V via a step-down transformer (10 kV / 0.4 kV) to supply local use for the ventilation and lighting systems of the underground parking garage and the lighting and irrigation systems of the surface park. When gravity block 3 falls to near the bottom of the shaft, the rubber buffer pad at the bottom first contacts the piston rod of the hydraulic buffer. The hydraulic buffer absorbs the impact energy, and at the same time, the energy recovery module converts the hydraulic energy into electrical energy and incorporates it into the energy storage system. According to measurements, each gravity block 3 outputs approximately 42 kWh of electrical energy during its descent (discharge efficiency 93%), and recovers approximately 0.38 kWh of electrical energy during a single buffering process (recovery rate 83%). The total electrical energy output of the 18 gravity blocks 3 in a single release is approximately 756 kWh + 6.84 kWh ≈ 762.84 kWh, with a release power of 1000 kW. The overall system efficiency is approximately 92.2% (energy storage efficiency 94% × energy release efficiency 93% + buffer energy recovery contribution ≈ 92.2%). Collaborative work phase: Throughout the day, the system operates in a collaborative manner: Underground parking garage unit 1 provides normal parking services, with parking spaces open to the residential area. The mechanical ventilation system automatically adjusts the fan speed based on the CO concentration sensor in the garage, and automatically increases the ventilation frequency when the CO concentration exceeds the standard. The automatic fire protection system operates continuously, with smoke detectors monitoring online 24 hours a day. The fire alarm control panel communicates with the PLC, and in the event of a fire, the PLC automatically controls the relevant shafts to suspend operation and execute safety procedures. The ground-level park units are open to the public. The irrigation system in green area 6 uses automatic drip irrigation, and the irrigation pumps are primarily powered by energy storage. The lighting facilities automatically turn on after sunset and automatically turn off after sunrise, prioritizing the use of energy storage for power. When power is insufficient, they switch to solar batteries and the municipal power grid. The control unit monitors the entire system's operating status in real time, collecting over 300 analog signals and 500 digital signals. The PLC completes a full scan cycle every 100ms, analyzing the collected operating parameters. If equipment malfunctions or abnormal parameters are detected (such as excessive vibration, excessive temperature, excessive humidity, positional deviation, or abnormal pressure), an alarm signal is immediately issued and displayed on the monitoring terminal. Simultaneously, emergency measures are taken according to the fault level. In case of a Level 1 fault (such as a broken wire rope or electromagnetic brake failure), immediately stop the machine and lock all gravity blocks 3. For level 2 faults (such as excessive temperature or abnormal vibration), reduce the load and notify maintenance personnel for repair. Level 3 faults (such as excessive humidity or abnormal lubrication) continue to operate but a maintenance warning is issued. According to actual operation data, the system has an availability rate of 99.2%, an annual downtime rate of ≤0.3%, an annual charge-discharge cycle of ≥330 times, and a system design life of ≥50 years. Technical effect data verification: This embodiment has been verified through actual operation (cumulative operation time exceeding 6 months), and the following measured data were obtained: Ground-based zero-landing energy storage reduces land area by 100% compared to traditional ground-based gravity energy storage (2500㎡ / 1000kW); the accompanying ground-based park has a green area of ​​5800㎡, and the annual carbon sequestration is measured to be ≥80t. Utilizing existing underground parking space, the civil engineering investment is reduced by approximately 38% (actual value) compared to traditional ground gravity energy storage; the construction period is 7 months (including design, construction and commissioning), which is about 55% shorter than traditional ground gravity energy storage (12-18 months). A single system can process approximately 1200 tons of solid waste (18 gravity blocks consume approximately 687 m³ of construction waste aggregate, equivalent to approximately 1200 tons), with a solid waste resource utilization rate of approximately 40%, reducing cement consumption by approximately 310 tons and reducing carbon emissions by approximately 802 tons of CO2. The measured overall system efficiency is 92.2% (charging efficiency 93.8%, discharging efficiency 92.6%, and buffer energy recovery contribution of about 0.8%), which is better than existing ground gravity energy storage systems (85%) and lithium battery energy storage systems (85%-90%). The system has an availability rate of 99.3%, an annual downtime rate of 0.25%, and a design life of 50 years. Based on Beijing's peak-valley electricity prices (peak price 0.85 yuan / kWh, valley price 0.32 yuan / kWh) and 330 arbitrage cycles per year: A single arbitrage profit = (0.85 - 0.32) × 4000 ≈ 2120 yuan (net profit of approximately 1947 yuan after deducting local self-consumption power losses), resulting in an annual arbitrage income of approximately 642,000 yuan. The annual parking revenue from 634 parking spaces is approximately 5 million yuan (based on a daily revenue of approximately 22 yuan per parking space and 330 operating days per year). The levelized cost of electricity (LCOS) is calculated to be approximately 0.28 yuan / kWh. The static investment payback period is approximately 7.8 years (including parking revenue). Example 3: A gravity energy storage system for urban underground garages. This example is basically the same as Example 1, except that the reserved area 12 of the vertical shaft is reduced in this example. However, this example also includes a top transfer and unhooking system. This embodiment enables the gravity block 3 to detach from the wire rope and be stored in the upper storage area after being lifted to the top of the shaft, and to reattach the wire rope during the energy release phase. Each shaft is equipped with a top transfer and unhooking system. Each shaft has an upper transfer and storage area at the top and a lower transfer and storage area at the bottom, respectively. With the help of an automatic unhooking device and a transfer trolley, the gravity block 3 can be automatically scheduled, stored, and maintained throughout its entire stroke range. Upper Warehouse Transfer and Storage Area: The upper warehouse transfer and storage area is located in the structural mezzanine between the top of the shaft and the ground park unit. This mezzanine is located below the shaft cover 8 and has a height of 2.5m (sufficient to accommodate the height of gravity block 3, the transfer trolley, and the unhooking space of the lifting beam). The bottom slab of the mezzanine is made of reinforced concrete, and two parallel tracks are laid on the surface. The tracks extend to both sides from directly above the shaft to form a horizontal transport channel. Each shaft is equipped with at least two upper storage stations, symmetrically arranged on both sides of the shaft's lifting channel. Each storage station is equipped with a gravity block 3 support base to support the gravity block 3 and relieve the load on the transfer trolley during long-term storage. Lower Garage Transfer and Storage Area: The lower garage transfer and storage area is located at the bottom of the shaft body and above the buffer mechanism 5. The lower garage storage area is located at the bottom of the shaft at the lowest level of the underground garage and shares the space at the bottom of the shaft with the buffer mechanism 5. The structure of the lower storage area is similar to that of the upper storage area: a horizontal transport channel is opened at the bottom of the shaft, and tracks are laid in the channel, extending to both sides along the bottom of the shaft. Each shaft is equipped with at least two lower storage stations, symmetrically arranged on both sides of the bottom of the shaft. The lower storage station is equipped with a gravity block 3 support base. Since it is located at the lowest underground level, the lower storage area needs to be designed with waterproofing and drainage in mind. Transfer trolleys: Two transfer trolleys are configured for each shaft, one for upper warehouse transfer and one for lower warehouse transfer. The two trolleys are identical in structure and interchangeable. Each trolley uses a steel frame structure, with a set of steel wheels at each of its four corners, and rolling bearings embedded in the wheels. The trolley is driven by a variable frequency motor, with a horizontal travel speed of 0.2 m / s and a positioning accuracy of ≤5 mm (achieved through speed regulation by the frequency converter and positioning by proximity switches). The top surface of the transfer trolley is equipped with a positioning groove that matches the shape of the bottom of the gravity block 3, ensuring that the gravity block 3 remains stable and does not slip during the transfer process. Each of the four corners of the trolley is equipped with a vertical guide wheel for correcting deviation when traveling on the track. Automatic unhooking device: The automatic unhooking device is installed between the lifting beam at the end of the wire rope and the lifting lug of the gravity block 3, and is used to realize the automatic connection and disconnection of the lifting beam and the gravity block 3. This device adopts a hydraulically driven pin-type automatic unhooking mechanism. The end of the wire rope is connected to a lifting beam, which is a welded H-beam structure. Each end of the beam has a lifting point (corresponding to the two lifting lugs of gravity block 3), and each lifting point is equipped with a set of pin mechanisms. A wire rope connector is located at the center of the top of the beam, connecting to the end of the wire rope. Each end of the lifting beam is equipped with a hydraulically driven pin. The front end of the pin is machined into a tapered shape for easy insertion. Each pin is driven by a double-acting hydraulic cylinder. The extension and retraction of the cylinder is controlled by an electromagnetic directional valve. Each cylinder has a hydraulic lock in both the rod-side and rodless sides to lock the pin position in the event of power failure, preventing accidental retraction that could cause the gravity block 3 to fall. The hydraulic power unit is installed in the middle of the spreader beam and includes a miniature hydraulic pump station, an electromagnetic directional valve assembly, and a pressure relay. The power and control signals of the hydraulic power unit are introduced through a slip ring, which is installed at the tail end of the winch drum. The slip ring body is made of an aluminum alloy shell. When the lifting beam aligns with the gravity block 3, a tapered guide sleeve is provided at each end of the beam to ensure precise alignment of the pin and the lug pin hole. Correspondingly, a tapered guide hole is provided at the top of the lug of the gravity block 3. When the lifting beam descends and approaches the gravity block 3, the guide tapered sleeve first inserts into the guide hole, and automatically guides the beam to move slightly for alignment through the tapered surface fit. The maximum allowable initial deviation is ±8mm. After alignment, the coaxiality error between the pin axis and the lug pin hole axis is ≤0.5mm, ensuring smooth pin insertion. Each pin mechanism's cylinder is equipped with two magnetic proximity switches, which detect the "extended in position" and "retracted in position" states of the pin, respectively. When the pin is fully extended through the lug pin hole, the proximity switch activates and sends a "connection confirmation" signal to the PLC; when the pin is fully retracted, it sends a "disconnection confirmation" signal to the PLC. Each storage station in the upper and lower storage areas is equipped with a positioning and locking mechanism to lock the transfer trolley within the station during storage by gravity block 3, preventing accidental displacement. The positioning and locking mechanism consists of an L-shaped locking hook, mounted on a concrete base beside the track at the storage station via a rotating shaft. A compression spring is connected to the tail end of the hook, allowing it to remain naturally locked. A wedge-shaped guide surface is provided at the front end (hook portion) of the hook, facilitating the opening of the hook when the trolley push rod enters. When the transfer trolley carrying the weight block 3 reaches the storage station, the push rod at the bottom of the trolley collides with the wedge-shaped guide surface of the hook, overcoming the spring force and pushing the hook to rotate and open. After the trolley passes, the push rod disengages, and the hook automatically resets under the spring's action, hooking onto the locking plate at the bottom of the trolley, thus achieving mechanical locking of the trolley. There are two scenarios when unlocking: Normal unlocking: The PLC sends a command to start the trolley motor to move forward slightly, and the push rod pushes the locking hook open again, releasing the locking hook; Emergency unlocking: Each storage station is equipped with a manual unlocking handle, which maintenance personnel can manually pull the wire rope to unlock the lock hook. Each storage station is also equipped with an arrival detection sensor, which can be an inductive proximity switch, mounted on a bracket at the end of the track, to detect whether the transfer trolley has reached the precise position and to transmit a confirmation signal to the PLC. Complete workflow of this embodiment (1) Storage process after energy storage is completed: The winch lifts gravity block 3 to the top of the shaft at a speed of 0.4 m / s; When the top of gravity block 3 is 100mm away from the top surface of the upper warehouse transfer trolley, the winch decelerates to 0.05m / s; The upper warehouse transfer trolley (initially positioned on the track directly above the shaft) is positioned directly below the shaft; The winch continues to slowly lower gravity block 3 (at a speed of 0.03 m / s) so that the bottom of gravity block 3 sits steadily in the positioning groove of the transfer trolley; The PLC confirms that gravity block 3 has made full contact with the trolley; The hydraulic cylinder of the automatic unhooking device actuates, and the two pins retract synchronously. After the magnetic proximity switch detects the "disengagement confirmation" signal, the PLC sends a command to the winch to raise the lifting beam, so that the beam is completely disengaged from the gravity block 3. The upper warehouse transfer trolley moves gravity block 3 along the track to the designated upper warehouse storage station; Once the arrival detection sensor confirms the arrival, the positioning and locking mechanism automatically locks the trolley. Gravity block 3 completes the upper storage and can be stored in this state for a long time. (2) Energy release and retrieval process before energy release: The PLC issues a retrieval command, and the positioning and locking mechanism unlocks. The upper warehouse transfer trolley moves gravity block 3 from the storage station to directly above the vertical shaft; The winch lowers the lifting beam so that the guide cone sleeves at both ends of the beam are inserted into the guide holes of the lifting lugs of the gravity block 3; The conical surface is automatically guided for alignment. After alignment is completed, the PLC checks whether the alignment was successful. After successful alignment is confirmed, the hydraulic cylinder is activated, and the two pins extend synchronously and insert into the lifting lug pin holes. After the magnetic proximity switch detects the "connection confirmation" signal, the PLC issues a command; The winch slowly lifts gravity block 3 to confirm that the connection is secure; The warehouse transfer trolley returns to its initial position; After the trolley exits into position, the winch begins to lower gravity block 3, entering the energy release phase. (3) Storage process after energy release: Gravity block 3 falls to the bottom of the shaft and stops about 200mm above the buffer mechanism 5 (its position is precisely controlled by a laser rangefinder). The warehouse transfer trolley (initially positioned at the bottom of the shaft, in standby position) moves to directly below the shaft. The winch continues to slowly lower gravity block 3 (at a speed of 0.03 m / s) so that the bottom of gravity block 3 sits in the positioning groove of the lower warehouse transfer trolley; PLC confirms that gravity block 3 is in full contact with the trolley (the tension of the winch wire rope drops to the no-load value). The automatic unhooking device is activated, the pin retracts, and the lifting beam separates from the gravity block 3; The winch lifting beam rises, completely separating it from gravity block 3; The lower warehouse transfer trolley moves gravity block 3 along the track to the lower warehouse storage station; The positioning and locking mechanism automatically locks the trolley, and gravity block 3 completes the storage in the warehouse. (4) Energy storage retrieval process before commencement: The PLC issues a retrieval command, and the positioning and locking mechanism unlocks. The lower warehouse transfer trolley moves gravity block 3 from the lower warehouse storage station to directly below the vertical shaft; The winch lowers the lifting beam, and the guide cone sleeve is automatically aligned by inserting into the guide hole of the lifting lug. The pin extends, completing the connection; The winch lifts gravity block 3, and after confirming that the connection is secure, it begins energy storage and lifting. In this embodiment, both the upper and lower storage areas are equipped with maintenance and inspection passages leading to each storage station. Maintenance personnel can use these passages to perform maintenance tasks such as visual inspection, concrete crack repair, and weld flaw detection on the gravity blocks 3 in their stored state. The maintenance passage in the lower storage area connects to the passage at the bottom of the underground parking garage and is accessed via a dedicated access control system. The other structures, installation methods, operation methods, and technical effects of this embodiment are similar to those of Embodiment 1, and will not be repeated here. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A gravity energy storage system for urban underground parking garages, characterized in that, include: The underground garage unit (1) is a multi-story reinforced concrete frame structure located underground. It is divided into a parking area (11) and a shaft reserved area (12). The shaft reserved area (12) is integrally formed with the main structure of the underground garage unit (1) and has a reinforced structure on its side wall. The vertical shaft energy storage unit (2) is set in the reserved area (12) of the vertical shaft and runs through each floor of the underground garage unit (1) from top to bottom. The vertical shaft energy storage unit (2) includes the vertical shaft body and a gravity block (3) that can be raised and lowered in the vertical shaft body. The ground park unit is located above the underground parking garage unit (1) and the vertical shaft energy storage unit (2); The transmission power generation unit (4) is connected to the gravity block (3) for the purpose of converting electrical energy into mechanical energy of the gravity block (3); The control unit is electrically connected to the underground garage unit (1), the vertical shaft energy storage unit (2), the transmission power generation unit (4), and the ground park unit, respectively, and is used to control the coordinated operation of each unit.

2. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The reinforcement structure is a reinforced concrete reinforcement layer set on the side wall of the reserved area (12) of the vertical shaft. The thickness of the reinforced concrete reinforcement layer is 100-150mm and the bearing capacity is ≥1200kN / ㎡.

3. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The gravity block (3) is made of concrete and filled with solid waste aggregate. There is a gap between the gravity block (3) and the inner wall of the shaft body.

4. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The vertical shaft energy storage unit (2) also includes a guide mechanism (21) arranged along the inner wall of the vertical shaft body. The guide mechanism (21) includes a guide rail (22) and a guide slider (23) connected to the gravity block (3). The guide slider (23) is embedded in the guide rail (22) to form a sliding fit.

5. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The vertical shaft energy storage unit (2) also includes a buffer mechanism (5) disposed at the bottom of the vertical shaft body. The buffer mechanism (5) includes a hydraulic buffer and an energy recovery module connected to the hydraulic buffer. The energy recovery module is used to convert the hydraulic energy generated during the buffering process into electrical energy.

6. The urban underground garage-type gravity energy storage system according to claim 1, characterized in that, The ground park unit includes a green area (6), a leisure walkway (7), and a shaft cover (8). The shaft cover (8) is located in the middle of the ground park unit and corresponds to the shaft energy storage unit (2). The shaft cover (8) is made of a light-transmitting material and has ventilation holes and inspection ports. The top of the shaft body is sealed to the shaft cover (8).

7. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The inner wall of the vertical shaft body is provided with a wear-resistant layer; A sealing bottom plate is provided at the bottom of the shaft body; A sealing device is provided at the connection between the underground garage unit (1) and the vertical shaft energy storage unit (2).

8. The urban underground parking garage-type gravity energy storage system according to claim 1, characterized in that, The transmission power generation unit (4) includes a winch, a gearbox and a generator. The winch is connected to the gravity block (3) by a wire rope. The output end of the winch is connected to the input end of the generator through the gearbox. The transmission power generation unit (4) also includes an electromagnetic braking device, which is electrically connected to the winch and is used to lock the winch in case of emergency shutdown.

9. The urban underground garage-type gravity energy storage system according to claim 1, characterized in that, The control unit includes a PLC controller and a sensor group. The sensor group is used to collect operating parameters in real time and transmit them to the PLC controller. The control unit triggers energy storage or energy release commands based on the real-time electricity price signal of the power grid.

10. An energy storage control method based on an urban underground parking garage-type gravity energy storage system according to any one of claims 1 to 9, characterized in that, Includes the following steps: Energy storage stage: The control unit issues an energy storage command during the off-peak period of the power grid, controls the transmission power generation unit (4) to lift the gravity block (3) and convert electrical energy into gravitational potential energy for storage; Energy release phase: During peak grid periods, the control unit issues an energy release command to control the gravity block (3) to fall and drive the transmission power generation unit (4) to generate electricity, converting gravitational potential energy into electrical energy output; and Collaborative working phase: The control unit performs collaborative control of the underground garage unit (1), the vertical shaft energy storage unit (2), the transmission power generation unit (4) and the ground park unit, and adjusts the power generation according to the power demand of the underground garage unit (1) and the ground park unit.

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