A prefabricated subsea concrete sphere battery and its construction method

Abstract

This invention relates to the field of subsea concrete sphere battery technology, and discloses a prefabricated subsea concrete sphere battery and its construction method. The battery includes a concrete base, with a prefabricated concrete sphere assembly mounted on the upper end of the concrete base. A generator set is installed inside the concrete base, and the generator set is connected to the prefabricated concrete sphere assembly via a first pipeline. A water pump is installed on one side of the generator set. The prefabricated concrete sphere assembly includes a concrete sphere top cover and a first sidewall component connected to one side of the concrete sphere top cover. A concrete sphere bottom cover is provided on the opposite side of the prefabricated concrete sphere assembly. The concrete sphere top cover, the first sidewall component, the second sidewall component, and the concrete sphere bottom cover are all connected and fixed using Ω-shaped compression sealing steel strips. This invention solves the problems of manufacturing, transportation, installation, and long-term sealing of ultra-large concrete spheres.

Description

Technical Field

[0001] This invention relates to the field of subsea concrete sphere battery technology, specifically to a prefabricated subsea concrete sphere battery and its construction method. Background Technology

[0002] Concrete sphere battery systems utilizing deep-sea hydrostatic pressure for large-scale energy storage offer significant advantages such as large capacity, long lifespan, and environmental friendliness. However, as this technology develops towards larger scales (e.g., sphere diameters exceeding 20 or even 30 meters), the manufacturing and construction of its core energy storage unit—the hollow concrete sphere—faces substantial challenges: 1. Prefabrication Challenges: For ultra-large diameter (e.g., >20 meters) thin-walled concrete spheres, traditional monolithic casting methods require enormous, high-precision molds, making on-site quality control difficult, curing periods long, and transportation and hoisting extremely challenging and costly. 2. Offshore Construction Risks: During towing, sinking, and installation at sea, the monolithic sphere is highly susceptible to wind and waves, making attitude control difficult and posing high risks of collision and capsizing. 3. Structural Reliability Concerns: If manufacturing limitations result in insufficient overall integrity of the sphere, it will severely impact its long-term sealing and structural safety under deep-sea high-pressure cyclic loads.

[0003] Existing large-scale concrete structures (such as immersed tunnels and large hydraulic structures) widely employ prefabrication and assembly technology. For example, subway shield tunnels use prefabricated segments assembled into rings and waterproofed with rubber gaskets. However, these technologies are mainly applied to columnar or arched structures, whose stress patterns (primarily bearing earth pressure and water pressure, with internal forces mainly consisting of axial compression and bending moment) are fundamentally different from the bidirectional membrane pressure state of the large spherical shell structure addressed in this invention under uniform deep-sea hydrostatic pressure. Directly applying existing segment connection methods (such as bolted connections) cannot effectively guarantee the overall mechanical properties of the spherical shell under high pressure and the watertightness of the joints.

[0004] Specifically, existing technologies lack an efficient and reliable prefabrication and segmentation scheme suitable for spherical thin-shell structures that can withstand huge uniform external pressure, lack a joint treatment technology and structure between spherical segments that can maintain long-term effective sealing under deep-sea high pressure, and lack a complete standardized construction process from land prefabrication, sea transportation to underwater assembly into a sphere.

[0005] Therefore, there is an urgent need in this field for an innovative solution that can overcome the bottlenecks in the manufacturing and construction of ultra-large concrete spheres, so as to promote the large-scale and economical application of submarine concrete sphere battery technology. Summary of the Invention

[0006] To address the problems in the prior art, this invention provides a prefabricated subsea concrete sphere battery and its construction method, which is achieved through the following technical solutions.

[0007] A prefabricated subsea concrete sphere battery includes a concrete base, an prefabricated concrete sphere assembly mounted on the upper end of the concrete base, a generator set disposed inside the concrete base, a first valve connected to one side of the generator set, the generator set and the prefabricated concrete sphere assembly being connected by a first pipeline, a water pump disposed on one side of the generator set, a second valve disposed on one side of the water pump, and the water pump being connected to the prefabricated concrete sphere assembly by a second pipeline, a controller disposed on the upper side inside the concrete base, and a cable interface disposed on the lower side inside the concrete base. The prefabricated concrete sphere assembly includes a concrete sphere top cover and a first sidewall component connected to one side of the concrete sphere top cover, and a second sidewall component connected to the other side of the first sidewall component. A concrete sphere bottom cover is provided on the other side of the prefabricated concrete sphere assembly opposite to the concrete sphere top cover. The concrete sphere top cover, the first sidewall component, the second sidewall component, and the concrete sphere bottom cover are all connected and fixed by an Ω-shaped compression sealing steel strip, and a fastening mounting seat is provided on the Ω-shaped compression sealing steel strip.

[0008] As a preferred embodiment of the present invention, the first sidewall component includes a first sidewall body and a first mounting seam formed on the outer edge of the first sidewall body, wherein the upper end of the first mounting seam is connected to a first connecting plate and the lower end of the first sidewall body is connected to a second connecting plate.

[0009] As a preferred embodiment of the present invention, the second sidewall member includes a second sidewall body and a second mounting seam formed on the outer edge of the second sidewall body, and a mating groove is formed at the outer end of the second sidewall body.

[0010] As a preferred embodiment of the present invention, the first sidewall member is arranged symmetrically about the second sidewall member as the axis of symmetry; the first sidewall member and the second sidewall member together constitute a set of units, the number of which is N, where N is an even number greater than or equal to 4, preferably 6 or 8.

[0011] As a preferred embodiment of the present invention, the connection between the components of the prefabricated concrete sphere assembly is provided with a continuous sealing groove, and a water-swellable rubber sealing strip is provided in the sealing groove.

[0012] A method for constructing a prefabricated subsea concrete sphere battery includes the following steps: S1: Design breakdown and prefabrication: Determine the number of sidewall blocks N and the size of the cover plate based on the diameter of the sphere and the water depth, design the shape of the components, reinforcement and joint structure, and prefabricate each component in batches at the land prefabrication plant. S2: Onshore trial assembly and sealing strip installation: Dry trial assembly is carried out before leaving the factory to check the fit of the joints. After passing the test, water-swellable rubber sealing strips are installed in the sealing groove. S3: Sea transport and sinking: Transport the components and base to the target sea area, first sink and fix the base, and then lift the components to the seabed; S4: Underwater assembly and sealing: Using the lower cover of the concrete sphere as a reference, install the first side wall component, the second side wall component and the upper cover of the concrete sphere in sequence, and permanently seal them by using an Ω-shaped compression sealing steel strip; S5: Overall Connection and Debugging: Underwater grouting and sealing of the joint between the sphere and the base, connecting pipelines, and debugging of system pressure and function.

[0013] As a preferred embodiment of the present invention, in step S1, the optimal number of blocks N is determined by finite element analysis, and precast components are cast using high-precision steel molds.

[0014] As a preferred embodiment of the present invention, in step S2, during trial assembly, all joint gaps and misalignments are required to be less than 2mm.

[0015] As a preferred embodiment of the present invention, in step S4, underwater assembly is performed by an underwater robot or diver, using a hydraulic wrench to tighten the high-strength bolts to the designed preload in two stages.

[0016] As a preferred embodiment of the present invention, in step S5, the underwater grouting uses an underwater non-dispersible grouting material to form a second seal between the sphere and the base.

[0017] The present invention has the following beneficial effects: 1. By breaking down the giant sphere into medium-sized components that can be standardized for production and are convenient for land and sea transportation, the problem of "not being able to make or transport" large-sized concrete structures has been completely solved, reducing mold costs and factory floor space.

[0018] 2. By transforming the objects being lifted at sea from uncontrollable giant spheres to easily manipulated individual components, the risks are significantly reduced. Underwater operations are simplified and can be carried out in parallel, with the overall construction cycle expected to be shortened by more than 30%.

[0019] 3. By introducing independent upper and lower concrete sphere covers, the mating surfaces are regular and easy to align during assembly. Furthermore, the sealing of the circumferential joint is more reliable and easier to implement than multi-point convergence sealing. A dual-insurance sealing system combining active and passive sealing is employed, utilizing water-swellable rubber and an Ω-shaped mechanical compression. The water-swellable rubber self-tightens upon contact with water, compensating for any potential material relaxation; the Ω-shaped compression sealing steel strip provides a strong and durable initial sealing force, together ensuring the joint remains leak-proof under decades of high pressure and cyclic loads.

[0020] 4. Despite the addition of joint structures, the savings in giant mold costs, high overall transportation and high-risk offshore operation costs, as well as the benefits brought by improved construction efficiency, have significantly reduced the overall construction cost of ultra-large capacity spherical batteries, greatly improving their economic efficiency.

[0021] 5. In extreme cases, if a component is damaged, theoretically the individual component can be replaced through underwater operations without scrapping the entire sphere, thus improving the maintainability of the system. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 : A schematic diagram of the overall structure of this invention; Figure 2 : A schematic diagram of the overall cross-sectional structure of the present invention; Figure 3 : A cross-sectional structural schematic diagram of the prefabricated concrete sphere assembly of the present invention; Figure 4 : Exploded structural diagram of the prefabricated concrete sphere assembly in this invention; Figure 5 : A schematic diagram of the connection structure between the first sidewall component and the second sidewall component in this invention; Figure 6 This invention Figure 3 Enlarged structural diagram at point A; Figure 7 This invention Figure 3 Enlarged structural diagram at point B; Figure 8 : Process flow diagram of the construction method in this invention.

[0024] The attached figures are labeled as follows: 10. Concrete base; 20. Prefabricated concrete sphere assembly; 21. Concrete sphere top cover; 22. First sidewall component; 221. First sidewall body; 222. First mounting joint; 223. First connecting plate; 224. Second connecting plate; 23. Second sidewall component; 231. Second sidewall body; 232. Second mounting joint; 233. Mating groove; 24. Concrete sphere bottom cover; 25. Ω-shaped compression sealing steel strip; 251. Fastening mounting base; 30. Generator set; 40. First valve; 50. First pipeline; 60. Water pump; 70. Second pipeline; 80. Second valve; 90. Controller; 100. Cable interface. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1 Reference Figure 1 - Figure 7 As shown, this is the first embodiment of the present invention, providing a prefabricated subsea concrete sphere battery and its construction method, including a concrete base 10, an prefabricated concrete sphere assembly 20 installed on the upper end of the concrete base 10, a generator set 30 disposed inside the concrete base 10, and a first valve 40 connected to one side of the generator set 30. The generator set 30 and the prefabricated concrete sphere assembly 20 are connected by a first pipeline 50. A water pump 60 is disposed on one side of the generator set 30, and a second valve 80 is disposed on one side of the water pump 60. The water pump 60 and the prefabricated concrete sphere assembly 20 are connected by a second pipeline 70. The upper side of the interior of the concrete base 10... A controller 90 is provided, and a cable interface 100 is provided on the lower inner side of the concrete base 10. The prefabricated concrete sphere assembly 20 includes a concrete sphere top cover 21 and a first side wall component 22 connected to one side of the concrete sphere top cover 21. A second side wall component 23 is connected to the other side of the first side wall component 22. A concrete sphere bottom cover 24 is provided on the other side of the prefabricated concrete sphere assembly 20 opposite to the concrete sphere top cover 21. The concrete sphere top cover 21, the first side wall component 22, the second side wall component 23 and the concrete sphere bottom cover 24 are all connected and fixed by an Ω-shaped compression sealing steel strip 25. A fastening mounting seat 251 is provided on the Ω-shaped compression sealing steel strip 25. The first sidewall component 22 and the second sidewall component 23 are located between the upper cover 21 and the lower cover 24 of the concrete sphere, and are evenly arranged along the circumference to form the equatorial region and most of the sidewalls of the sphere. The upper and lower end faces of each sidewall component are annular splicing surfaces that match the cover plate, rather than sharp corners, and the two sides are longitudinal joint surfaces. Furthermore, the first sidewall component 22 is symmetrically arranged about the second sidewall component 23 as the axis of symmetry. The first sidewall component 22 and the second sidewall component 23 together form a set of units, and the number of these units is N, where N is an even number greater than or equal to 4, preferably 6 or 8. The splicing surfaces of the upper cover 21 of the concrete sphere, the first sidewall component 22, and the N first sidewall components 22 and the second sidewall component 23 together form two parallel annular joints, namely "latitude joints".

[0027] The first sidewall component 22 includes a first sidewall body 221 and a first mounting seam 222 formed on the outer edge of the first sidewall body 221. The upper end of the first mounting seam 222 is connected to a first connecting plate 223, and the lower end of the first sidewall body 221 is connected to a second connecting plate 224. The second sidewall component 23 includes a second sidewall body 231 and a second mounting seam 232 formed on the outer edge of the second sidewall body 231. The outer end of the second sidewall body 231 is provided with a mating groove 233. The first sidewall body 221 is symmetrically arranged on the upper and lower sides of the second sidewall body 231, so that the upper and lower sidewall bodies 221 respectively cooperate with the upper cover 21 and the lower cover 24 of the concrete sphere. The first connecting plate 223 is connected to the upper cover 21 or the lower cover 24 of the concrete sphere. The second connecting plate 224 is provided on the side of the first sidewall body 221 on the upper and lower sides near the second sidewall body 231, so that the second connecting plate 224 is configured to cooperate with the mating groove 233 to complete the docking installation. At the same time, the first installation seam 222 and the second installation seam 232 are respectively provided on the first sidewall body 221 and the second sidewall body 231 to cooperate with the setting of the Ω-shaped compression sealing steel strip 25 to complete the overall connection and fixation of the assembled concrete sphere assembly 20. Furthermore, continuous sealing grooves are provided at the connection points between the components in the prefabricated concrete sphere assembly 20, and water-swellable rubber sealing strips are installed in the sealing grooves. Furthermore, the top of the concrete base 10 is provided with a socket that matches the lower cover 24 of the concrete sphere in the prefabricated concrete sphere assembly 20. The lower cover 24 of the concrete sphere is embedded in the socket and fixed by a high-performance underwater sealing material. All power and control equipment is integrated inside the concrete base 10.

[0028] Example 2 Combination Figure 1 - Figure 2 and Figure 8As shown, this is the second embodiment of the present invention, which, based on embodiment 1, provides a method for constructing a prefabricated subsea concrete sphere battery, including the following steps: S1: Design breakdown and prefabrication: Determine the number of sidewall blocks N and the size of the cover plate based on the diameter of the sphere and the water depth, design the shape of the components, reinforcement and joint structure, and prefabricate each component in batches at the land prefabrication plant. S2: Onshore trial assembly and sealing strip installation: Dry trial assembly is carried out before leaving the factory to check the fit of the joints. After passing the test, water-swellable rubber sealing strips are installed in the sealing groove. S3: Sea transport and sinking: Transport the components and base to the target sea area, first sink and fix the base, and then lift the components to the seabed; S4: Underwater assembly and sealing: Using the concrete sphere lower cover 24 as a reference, install the first side wall component 22, the second side wall component 23 and the concrete sphere upper cover 21 in sequence, and permanently seal them by using the Ω-shaped compression sealing steel strip 25. S5: Overall Connection and Debugging: Underwater grouting and sealing of the joint between the sphere and the base, connecting pipelines, and debugging of system pressure and function.

[0029] In S1, the optimal number of blocks N is determined by finite element analysis, and precast components are cast using high-precision steel molds.

[0030] In S2, during trial assembly, all joint gaps and misalignments must be less than 2mm.

[0031] In S4, underwater assembly is performed by underwater robots or divers, using hydraulic wrenches to tighten high-strength bolts to the designed preload in two stages.

[0032] In S5, underwater grouting uses underwater non-dispersible grouting material to form a second seal between the sphere and the base.

[0033] Example 3 Reference Figure 1 - Figure 8 The image shows the third embodiment of the present invention. Based on embodiments 1 and 2, this embodiment details the specific implementation process of constructing a prefabricated subsea concrete sphere battery with a diameter of 30 meters and deployed on the seabed at a water depth of 150 meters: Design and Prefabrication: Based on finite element analysis, the number of sphere segments N is determined to be 8, meaning the total number of the first sidewall component 22 and the second sidewall component 23 is 8, and it is assembled from a concrete sphere top cover 21 and a concrete sphere bottom cover 24. The concrete sphere shell is designed to be 0.7 meters thick, using C80 high-performance marine concrete, and the reinforcement uses double-layer HRB400 steel mesh, with optimized arrangement based on the stress characteristics of the sphere shell. In the land-based prefabrication plant, 8 sets of high-precision curved steel molds corresponding to the sidewall components, as well as special steel molds for the top and bottom cover plates, are used for batch prefabrication. On the joint surface of each prefabricated component, two continuous annular sealing grooves with a depth of 30 mm and a width of 30 mm are prefabricated, and Ω-shaped compression sealing steel strips 25 with internal threaded holes are pre-embedded near the groove openings. The concrete base 10 adopts a caisson structure, with an annular socket at the top for docking with the opening at the center of the concrete sphere bottom cover 24.

[0034] Land-based trial assembly and sealing strip installation: On a dedicated dry dock or assembly site, a temporary support system is erected. The concrete sphere lower cover 24, the first side wall component 22, the second side wall component 23, and the concrete sphere upper cover 21 are erected in sequence to form a complete spherical cavity. Precision instruments such as a total station are used to measure the gaps and misalignments of all joints (i.e., the top annular joint, the bottom annular joint, and the longitudinal joints), ensuring that they are all less than the design allowable value of 2mm. After successful trial assembly, the components are disassembled. A rectangular sealing strip made of EPDM rubber and water-swellable rubber composite with matching cross-sectional dimensions is pressed into each sealing groove.

[0035] Marine transport and sinking: Using a semi-submersible vessel or a large deck barge, the prefabricated components, the concrete base 10 weighing approximately 2,000 tons, and accessories such as Ω-shaped compression sealing steel straps 25 and bolts are transported to the target sea area. First, the concrete base 10 is sunk to the predetermined position on the seabed at a depth of 150 meters using a crane vessel, and precise leveling and foundation fixing are performed using the base leveling system. Subsequently, using a crane vessel in conjunction with a special balancing hoist, the concrete sphere top cover 21, the first side wall component 22, the second side wall component 23, and the concrete sphere bottom cover 24 are sequentially hoisted above the seabed operation area, and initially positioned by an underwater robot (ROV).

[0036] Underwater Assembly and Sealing: During ROV operation, the lower concrete sphere cover 24 is precisely embedded into the socket of the concrete base 10 and temporarily fixed. Using the lower concrete sphere cover 24 as a reference, the ROV guides the first sidewall component 22 and the second sidewall component 23 to be installed sequentially around its circumference. The components are initially fixed to the bottom cover plate and adjacent components via temporary hydraulic connections, forming a spherical shell with an open top. The upper concrete sphere cover 21 is hoisted to the top opening of the shell to complete alignment. The ROV carries the Ω-shaped compression sealing steel strip 25 to each joint. This steel strip has an Ω-shaped cross-section, with its inner curved surface matching the outer contour of the spherical shell. The ROV uses a hydraulic wrench to screw the high-strength bolts on both sides of the steel strip into the pre-embedded threaded holes of the connectors on the components, and tightens them in two stages (e.g., first to 70% of the design preload, then to 100%) to the final design preload (e.g., 500kN). The tightening sequence is: first the bottom annular joint, then all longitudinal joints, and finally the top annular joint.

[0037] Overall Connection and Commissioning: At the annular gap between the concrete sphere's lower cover 24 and the concrete base 10, pressure grouting is performed using underwater non-dispersible grout to form a robust and sealed consolidation. The inner cavity of the sphere is connected to the water pump 60 and the generator set 30 via the base equipment compartment via the second pipeline 70 and the first pipeline 50. The first valve 40 and the second valve 80 are closed, and a pressure test is performed inside the sphere to check the joint sealing performance. Simultaneously, the water pump, generator, and controller 90 are tested in conjunction with each other. After passing the test, the system can be put into operation.

[0038] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A prefabricated subsea concrete sphere battery, characterized in that, The system includes a concrete base (10), an assembled concrete sphere assembly (20) is installed on the upper end of the concrete base (10), a generator set (30) is installed inside the concrete base (10), and a first valve (40) is connected to one side of the generator set (30). The generator set (30) and the assembled concrete sphere assembly (20) are connected by a first pipeline (50). A water pump (60) is installed on one side of the generator set (30), and a second valve (80) is installed on one side of the water pump (60). The water pump (60) and the assembled concrete sphere assembly (20) are connected by a second pipeline (70). A controller (90) is installed on the upper side inside the concrete base (10), and a cable interface (100) is installed on the lower side inside the concrete base (10). The prefabricated concrete sphere assembly (20) includes a concrete sphere top cover (21) and a first side wall component (22) connected to one side of the concrete sphere top cover (21), and a second side wall component (23) is connected to the other side of the first side wall component (22). A concrete sphere bottom cover (24) is provided on the other side of the prefabricated concrete sphere assembly (20) opposite to the concrete sphere top cover (21). The concrete sphere top cover (21), the first side wall component (22), the second side wall component (23) and the concrete sphere bottom cover (24) are all connected and fixed by an Ω-shaped compression sealing steel strip (25). A fastening mounting seat (251) is provided on the Ω-shaped compression sealing steel strip (25).

2. The prefabricated subsea concrete sphere battery according to claim 1, characterized in that, The first sidewall component (22) includes a first sidewall body (221) and a first mounting seam (222) opened on the outer edge of the first sidewall body (221). The upper end of the first mounting seam (222) is connected to a first connecting plate (223), and the lower end of the first sidewall body (221) is connected to a second connecting plate (224).

3. The prefabricated subsea concrete sphere battery according to claim 1, characterized in that, The second sidewall component (23) includes a second sidewall body (231) and a second mounting seam (232) opened on the outer edge of the second sidewall body (231), and a mating groove (233) is opened at the outer end of the second sidewall body (231).

4. The prefabricated subsea concrete sphere battery according to claim 2, characterized in that, The first sidewall member (22) is arranged symmetrically about the second sidewall member (23) as the axis of symmetry; the first sidewall member (22) and the second sidewall member (23) together form a unit, the number of which is N, where N is an even number greater than or equal to 4, preferably 6 or 8.

5. The prefabricated subsea concrete sphere battery according to claim 1, characterized in that, The prefabricated concrete sphere assembly (20) has continuous sealing grooves at the connection points between its components, and water-swellable rubber sealing strips are installed in the sealing grooves.

6. A method for constructing a prefabricated subsea concrete sphere battery, characterized in that, Includes the following steps: S1: Design breakdown and prefabrication: Determine the number of sidewall blocks N and the size of the cover plate based on the diameter of the sphere and the water depth, design the shape of the components, reinforcement and joint structure, and prefabricate each component in batches at the land prefabrication plant. S2: Onshore trial assembly and sealing strip installation: Dry trial assembly is carried out before leaving the factory to check the fit of the joints. After passing the test, water-swellable rubber sealing strips are installed in the sealing groove. S3: Sea transport and sinking: Transport the components and base to the target sea area, first sink and fix the base, and then lift the components to the seabed; S4: Underwater assembly and sealing: Based on the concrete sphere lower cover (24), install the first side wall component (22), the second side wall component (23) and the concrete sphere upper cover (21) in sequence, and permanently seal them by means of Ω-shaped compression sealing steel strip (25); S5: Overall Connection and Debugging: Underwater grouting and sealing of the joint between the sphere and the base, connecting pipelines, and debugging of system pressure and function.

7. The construction method of the prefabricated subsea concrete sphere battery according to claim 6, characterized in that, In S1, the optimal number of blocks N is determined by finite element analysis, and precast components are cast using high-precision steel molds.

8. The construction method of the prefabricated subsea concrete sphere battery according to claim 6, characterized in that, In S2, during trial assembly, all joint gaps and misalignments must be less than 2mm.

9. The construction method of the prefabricated subsea concrete sphere battery according to claim 6, characterized in that, In S4, underwater assembly is performed by an underwater robot or diver, using a hydraulic wrench to tighten the high-strength bolts to the designed preload in two stages.

10. The construction method of the prefabricated subsea concrete sphere battery according to claim 6, characterized in that, In step S5, the underwater grouting uses an underwater non-dispersible grouting material to form a second seal between the sphere and the base.

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