Energy storage high rate submerged safety battery pack system

Abstract

The application discloses an energy storage high-multiplying submerged safety battery pack system to solve the problem of uneven temperature of the battery core existing in the heat dissipation scheme of the existing battery system. The application comprises a box body and an upper cover, at least two rows of high-power battery modules are arranged in the box body, and a liquid cooling plate is arranged between adjacent battery modules; the box body is filled with submerged liquid; the submerged liquid absorbs the heat of the battery module, the liquid cooling plate exchanges heat with the submerged liquid and / or directly exchanges heat with the battery module, a temperature difference is established in the battery module in the heat exchange process, the submerged liquid is driven to form microcirculation in the box body, and finally the heat is discharged from the system through the circulating cooling liquid in the liquid cooling plate; the overall structure of the application is compact, the composite heat dissipation scheme of "full immersion + built-in liquid cooling plate" is adopted, the heat dissipation capacity is high, the safety performance is high, the top-bottom temperature difference is reduced, the temperature uniformity of the battery core monomer itself is improved, the pack cycle life is improved, and thermal runaway and heat spread are avoided with a high probability.

Description

Technical Field

[0001] This application relates to the field of thermal management technology for energy storage packs, specifically to a high-rate immersion safety battery pack system for energy storage. Background Technology

[0002] Currently, in the field of thermal management for energy storage packs, solutions such as natural cooling, air cooling, liquid cooling, and direct cooling are all addressing the issue of temperature rise and temperature difference within the battery cells, with the goal of improving cell consistency and cycle life. However, these solutions all have certain drawbacks. Because heat dissipation is achieved through localized contact with the battery cells, the temperature difference between the top and bottom is large, resulting in extremely uneven temperature distribution within individual cells, which leads to a reduction in cell lifespan.

[0003] To overcome the aforementioned limitations, patent document CN114006103A discloses an immersion liquid-cooled battery system, which includes a battery box containing battery cell modules and a coolant for immersing the battery cell modules. In practical applications, the battery cell modules are directly immersed in the coolant, and an external water pump drives the coolant flow to remove the heat generated during battery charging and discharging. However, this solution still has the following drawbacks: its coolant flow field relies on external forced circulation, resulting in disordered flow that easily creates dead zones, poor temperature uniformity, and low heat dissipation efficiency; furthermore, the opening edge of the battery box is a simple flat design, and the seal relies entirely on the planar clamping force generated by the top cover. Once leakage occurs at the sealing interface due to long-term aging, vibration, or assembly errors, the internal coolant may seep out directly along the gaps, not only contaminating the equipment but also potentially posing electrical safety risks between adjacent battery packs. Summary of the Invention

[0004] Therefore, this application provides a high-rate immersion safety battery pack system for energy storage to solve the problem of uneven cell temperature in existing battery system heat dissipation solutions.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A high-rate immersion safety battery pack system includes: a housing and a top cover located on the top of the housing. The housing has at least two rows of battery modules inside, and vertically arranged liquid cooling plates are arranged between adjacent battery modules. The liquid cooling plates have coolant channels inside, and the liquid cooling plates have coolant inlets and coolant outlets for connecting to an external cooling circulation system.

[0007] The interior of the enclosure is filled with an immersion liquid to completely submerge the battery module and the liquid cooling plate. The immersion liquid absorbs the heat generated by the battery module. The liquid cooling plate exchanges heat with the immersion liquid after heat exchange and / or directly with the battery module, and establishes a temperature difference within the battery module. This temperature difference drives the immersion liquid to form a micro-circulation within the enclosure, and the heat is ultimately carried away by the circulating coolant inside the liquid cooling plate.

[0008] Optionally, the temperature difference-driven microcirculation specifically refers to:

[0009] On either side of the liquid cooling plate, the immersion liquid closer to the liquid cooling plate has a lower temperature and flows downward, while the immersion liquid farther away from the liquid cooling plate has a higher temperature and flows upward, thereby forming a clockwise micro-circulation in the battery module area on the left side of the liquid cooling plate and a counterclockwise micro-circulation in the battery module area on the right side of the liquid cooling plate.

[0010] Optionally, both sides of the liquid cooling plate are provided with fin structures, which extend into the immersion liquid; or,

[0011] The liquid cooling plate is a harmonica tube type liquid cooling plate, including: a harmonica tube body, the inside of the tube body is provided with fin structures along its length, and the coolant flow channels are formed on both sides of the tube body corresponding to the fin structures.

[0012] Optionally, each of the battery modules includes a plurality of individual battery cells arranged sequentially in the same direction, with gaps between adjacent individual battery cells forming a flow channel for the immersion liquid;

[0013] The capacity of the individual battery cell is not less than 300Ah, and the battery pack system is configured to support a discharge rate of not less than 1C.

[0014] Optionally, the enclosure is formed by sheet metal welding;

[0015] The interior of the box is provided with a middle beam arranged perpendicular to the liquid cooling plate. The top opening edge of the box is provided with an outward and upward extended flange structure. The flange structure and the top surface of the box form a boss. The top cover and the flange structure are connected by bolts, and a sealing gasket is provided between the top cover and the flange structure.

[0016] Optionally, the battery module is assembled using the CTP method, and its multiple individual cells are connected through a module-free CCS.

[0017] Insulating blocks are installed on the top of multiple individual battery cells.

[0018] Optionally, the battery module is provided with wedge-shaped blocks at both ends, and a compressible inter-cell buffer pad is provided between adjacent individual cells;

[0019] A polyurethane thermally conductive structural adhesive is applied between the bottom of the individual battery cell and the bottom plate of the housing.

[0020] The insulating pressure block is a strip-shaped pressure strip, and both ends and the middle of the pressure strip are connected to the box body by bolts; the pressure strip is a sheet metal bending part, and its exterior is coated with an epoxy resin insulating layer.

[0021] Optionally, the top of the cover is provided with a handle and an explosion-proof valve.

[0022] Optionally, the outer side of the housing is provided with an inlet and an outlet that are respectively connected to the coolant inlet and coolant outlet, as well as an oil level sight glass, a lifting point, and a battery management unit. The oil level sight glass is used to observe the state of the immersion liquid, the lifting point is used for lifting, transporting and installing the entire battery pack, and the battery management unit is used to manage the operating status of the battery modules.

[0023] Optionally, the immersion liquid is a hydrocarbon liquid or a fluorinated liquid;

[0024] The tank is also equipped with a circulation pump to drive the immersion liquid to circulate.

[0025] Compared with the prior art, this application has at least the following beneficial effects:

[0026] 1. Based on further analysis and research of existing technical problems, this application provides a high-rate immersion safety battery pack system, including a housing and a top cover. The housing contains at least two rows of battery modules, with vertically arranged liquid cooling plates between adjacent modules. The housing is filled with immersion fluid to completely submerge the battery modules and liquid cooling plates. The immersion fluid absorbs the heat generated by the battery modules. The liquid cooling plates exchange heat with the immersion fluid and / or directly with the battery modules to remove heat from the battery modules. The heat exchange process between the liquid cooling plates and the battery modules establishes a temperature difference within the battery modules, driving the immersion fluid to form a micro-circulation within the housing. The immersion fluid dissipates heat directly to the large surfaces of the battery cells through the gaps between the individual cells. The lower-temperature immersion fluid flows downwards, while the higher-temperature immersion fluid floats upwards, ultimately cooling through the internal circulation of the liquid cooling plates. The liquid coolant removes heat generated by the battery module. This application features a compact and rationally designed overall structure, employing a composite heat dissipation solution of "full immersion + built-in liquid cooling plate." By placing a liquid cooling plate radiator in the middle between the battery modules, a 360° all-around heat exchange mode is achieved, resulting in strong heat dissipation capacity, reduced top-to-bottom temperature difference, and improved temperature uniformity of the individual cells. This enhances pack cycle life, safety, and consistency, significantly reducing the likelihood of thermal runaway and heat propagation. The liquid cooling plate also features fins, increasing the heat exchange area with the immersion liquid and further improving heat dissipation capacity. This heat dissipation solution allows the discharge rate of high-capacity, large-cell packs to be adjusted from 0.5P to 1P or even higher, meeting the stringent requirements for high-power response in frequency regulation and other scenarios, enabling the successful implementation of high-discharge-rate packs required for frequency regulation projects.

[0027] 2. The immersion liquid in this application is a hydrocarbon, which has good insulation properties, stable performance, low cost and good compatibility. A large amount of immersion liquid can avoid the risk of thermal propagation caused by thermal runaway of a single cell, greatly reduce the probability of thermal runaway of the whole package and improve the safety of long-term use.

[0028] 3. This application incorporates an upturned edge structure on the top of the enclosure, which forms a boss with the top surface of the enclosure. This boss structure effectively blocks and accommodates any potential leakage of the immersion liquid, preventing it from overflowing. Furthermore, the top cover adopts a handle structure for easy installation and disassembly. An explosion-proof valve is also installed on the top of the top cover, with its inlet height higher than the maximum design liquid level of the immersion liquid, but lower than or level with the top surface of the upturned edge structure. By sharing the installation height space of the explosion-proof valve and echoing the upturned edge of the sheet metal welded enclosure, the overflow of the immersion liquid is further prevented, improving the sealing safety of the system.

[0029] 4. The outer side of the enclosure of this application is also equipped with an oil level indicator, a lifting point and a battery management unit (external BMU). The oil level indicator is used to visually check the liquid level, color clarity and whether there is sediment, bubbles or abnormalities in the immersion liquid in the enclosure. The lifting point is used for the lifting, transportation and installation of the entire battery pack. The external BMU is used to monitor and manage the operating status of the battery module, which not only improves the reliability of the electronic system but also facilitates maintenance and repair.

[0030] 5. The box body of this application adopts sheet metal welding, which improves the structural strength and has low cost. Sheet metal box body does not require molds, which improves product flexibility and saves mold fees and other expenses.

[0031] 6. The pack module of this application adopts the CTP method for assembly, which makes the assembly more efficient, reduces the number of parts, and lowers the cost;

[0032] Compressible inter-cell buffer pads are added between individual cells to solve the problem of initial pre-tightening force of the cells, and wedge blocks are added at both ends of the battery module to facilitate end-pressing installation; at the same time, in order to prevent the cells from jumping up and down, polyurethane thermally conductive structural adhesive is applied to the bottom of the individual cells to achieve a reliable fixed connection with the bottom plate of the casing.

[0033] To prevent the battery module from shaking during transportation, insulating blocks (bars) are installed on the top of multiple individual cells to fix and constrain the cells. The ends and middle of the bar are connected to the housing by bolts. The bar is made of sheet metal bending parts and is coated with 0.5-1.5mm epoxy resin insulating protective glue. The bar is easy to process and has low cost. The insulation protection meets DC4380V.

[0034] 7. The liquid cooling plate of this application has two forms, among which the harmonica tube type liquid cooling plate has thinner tube walls, lighter weight, and lower cost.

[0035] 8. This application can also install a circulation pump inside the tank to increase the circulation performance of the internal immersion liquid and solve the problem of uneven heat distribution caused by low immersion thermal conductivity. Attached Figure Description

[0036] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0037] Figure 1 This is a schematic diagram of the structure of a high-rate immersion safety battery pack system for energy storage provided in one embodiment of this application;

[0038] Figure 2 for Figure 1 The diagram shown is an exploded view.

[0039] Figure 3 for Figure 1 A schematic diagram of the micro-circulation formed within the battery pack;

[0040] Figure 4 for Figure 1 A schematic diagram of the structure of a liquid cooling plate;

[0041] Figure 5 for Figure 4 Partial schematic diagram shown Figure 1 ;

[0042] Figure 6 for Figure 4 Partial schematic diagram shown Figure 2 ;

[0043] Figure 7 for Figure 1 A schematic diagram of another type of liquid cooling plate;

[0044] Figure 8 for Figure 7 Partial schematic diagram shown Figure 1 ;

[0045] Figure 9 for Figure 7 Partial schematic diagram shown Figure 2 ;

[0046] Figure 10 for Figure 2 A schematic diagram of the structure with a middle beam and liquid cooling plate installed inside the middle box;

[0047] Figure 11 for Figure 2 Schematic diagram of the upper and middle covers;

[0048] Figure 12 for Figure 2 A partial schematic diagram of the battery cell section;

[0049] Figure 13 for Figure 9 A partial schematic diagram of the upper and middle flange structure;

[0050] Figure 14 for Figure 1 Schematic diagram of the internal structure of the middle box;

[0051] Figure 15 for Figure 1 The side view diagram is shown.

[0052] Explanation of reference numerals in the attached figures:

[0053] 1. Housing; 101. Upward-flanged structure; 102. Boss; 2. Intermediate beam; 3. Top cover; 4. Liquid cooling plate; 41. Coolant flow channel; 5. Individual battery cell; 6. Insulating block; 7. Module-less CCS; 8. Fin structure; 9. Gap; 10. Handle; 11. Explosion-proof valve; 12. Oil level indicator; 13. Lifting point; 14. Battery management unit; 15. Water inlet; 16. Water outlet. Detailed Implementation

[0054] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "including," "comprising," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0056] The terms used in this application, such as "upper," "lower," "left," "right," and "middle," are generally used to indicate the general relative positional relationship for the purpose of intuitive understanding by referring to the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product.

[0057] like Figures 1-15 As shown, this application provides a high-rate immersion safety battery pack system for energy storage. The battery pack system includes: a housing 1 and a top cover 3 located on the top of the housing 1. At least two rows of battery modules are arranged inside the housing 1. A vertically arranged liquid cooling plate 4 is arranged between adjacent battery modules. The liquid cooling plate 4 has a coolant flow channel 41 inside and a coolant inlet and a coolant outlet for connecting to an external cooling circulation system.

[0058] The interior of the housing 1 is filled with an immersion liquid, which is either a hydrocarbon liquid or a fluorinated liquid, used to completely immerse the battery module and the liquid cooling plate 4. This immersion heat dissipation solution is a technical method that completely immerses the battery cells in a specific medium, and achieves heat dissipation, insulation and other functions through the physical or chemical properties of the medium. The immersion liquid is used to absorb the heat generated by the battery module. The liquid cooling plate 4 exchanges heat with the immersion liquid after heat exchange and / or directly exchanges heat with the battery module to remove the heat from the battery module. The heat exchange process between the liquid cooling plate 4 and the battery module establishes a temperature difference inside the battery module. This temperature difference is used to drive the immersion liquid to form a micro-circulation within the housing 1. The immersion liquid directly dissipates heat to the large surface of the battery cell 5 through the gaps 9 between the individual battery cells 5. The low-temperature immersion liquid flows downward and the high-temperature immersion liquid floats upward. Finally, the heat generated by the battery module is removed by the circulating coolant inside the liquid cooling plate 4.

[0059] The aforementioned temperature-driven microcirculation is specifically as follows: on either side of the liquid cooling plate 4, the immersion liquid closer to the liquid cooling plate 4 has a lower temperature and flows downwards, while the immersion liquid farther from the liquid cooling plate 4 has a higher temperature and flows upwards (floats). This creates a clockwise microcirculation in the battery module region on the left side of the liquid cooling plate 4 and a counter-clockwise microcirculation in the battery module region on the right side of the liquid cooling plate 4. (See [link to relevant documentation]). Figure 3 The heat is ultimately carried away by the circulating coolant inside the liquid cooling plate 4.

[0060] In this application, the liquid cooling plate 4 and the external cooling circulation system (external water machine) form a first circulation, providing a stable, efficient and controllable main cold source for the system, ensuring that heat can be removed in the end and continuously; at the same time, the micro-circulation driven by the temperature difference forms a second circulation, which undertakes the function of heat transfer and realizes contact heat exchange with the heat dissipation surface of the battery cell. The two circulations work together to achieve uniform and efficient heat dissipation of the battery module, improving the consistency, safety and service life of the battery system.

[0061] Preferably, it also includes a circulation pump, which is located inside the housing 1, increasing the circulation performance of the internal immersion liquid and solving the problem of uneven heat distribution caused by low immersion thermal conductivity.

[0062] In one embodiment, such as Figures 4-6 As shown, fin structures 8 are provided on both sides of the liquid cooling plate 4, and the fin structures 8 extend into the immersion liquid; the fin structures 8 are triangular fins, which are used to increase the heat exchange area; and the fins are welded to both sides of the liquid cooling plate 4 by vacuum brazing process, so as to efficiently remove the heat of the battery system through convection heat exchange with the immersion liquid.

[0063] This liquid cooling plate 4, as a liquid-cooled finned heat sink, has the following advantages: the extruded profile and fins are fused together, and the fins are finally welded by vacuum brazing process, increasing the heat exchange area of ​​the immersion liquid; it is placed vertically between two rows of cells and immersed in hydrocarbon liquid or fluorinated liquid, and its two sides exchange heat with the immersion liquid through the fins at the same time, which increases the contact area and heat exchange efficiency.

[0064] In another embodiment, such as Figures 7-9 As shown, the liquid cooling plate 4 is a harmonica tube type liquid cooling plate, including: a harmonica tube body, with fin structures 8 arranged along the length of the tube body, and coolant flow channels 41 formed on both sides of the tube body corresponding to the fin structures 8; the fin structures 8 are arranged inside the tube body by vacuum brazing to increase the heat exchange area.

[0065] This liquid cooling plate 4, used as a liquid cooling heat sink for harmonica tube fins, has the following advantages: light weight, low cost, and high heat dissipation effect; it is placed between two rows of battery modules, dissipating heat from the battery cells by contacting the side of the cells, while the battery pack is immersed in a liquid that covers the height of the battery cells, thus achieving contact heat dissipation.

[0066] Preferably, each battery module includes multiple battery cells 5 arranged sequentially in the same direction. Each battery cell 5 is a high-power cell with high-rate charge and discharge capability. The capacity of each battery cell 5 is not less than 300Ah, and the battery pack system is configured to support a discharge rate of not less than 1C.

[0067] A gap 9 is provided between adjacent battery cells 5. The gap 9 forms a flow channel for the immersion liquid. The flowing immersion liquid dissipates heat over a large area of ​​the battery cell, increasing the heat exchange area of ​​the battery cell.

[0068] More preferably, the gap 9 is 1-3 mm.

[0069] Preferably, the enclosure 1 is formed by sheet metal welding, and the IP rating meets the IP68 protection level. This enclosure 1 is used as the enclosure 1 for an immersion battery pack, with high structural strength, good welding sealing, and complete compatibility with immersion liquid.

[0070] like Figure 10 As shown, the interior of the housing 1 is provided with a middle beam 2 arranged perpendicularly to the liquid cooling plate 4. The middle beam 2 and the liquid cooling plate 4 together divide the cell array into four relatively independent battery module areas.

[0071] More preferably, such as Figure 13As shown, the top opening edge of the housing 1 is provided with an outward and upward extending flange structure 101, which increases the sealing contact area between the top cover 3 and the housing 1. The flange structure 101 and the top surface of the housing 1 form a boss 102 to prevent the immersion liquid from overflowing. If the immersion liquid leaks or seeps oil, the boss 102 can ensure that the leakage will not spread directly to the outside of the housing 1, and will not harm other packs, thus solving the hidden dangers caused by large-area sealing leakage. In addition, the flange structure 101 further improves the integration and space utilization of the entire battery pack system, allowing the slave control unit to be installed in the recessed space at the bottom of the side wall of the housing 1.

[0072] This sheet metal enclosure 1 structure achieves enhanced strength while being more economical than the aluminum profile enclosure 1. The sheet metal material of enclosure 1 is Q235 with a thickness of 2mm, which is 0.8mm thicker than the traditional sheet metal enclosure 1. This is to cope with the impact force brought by the immersion liquid pressure.

[0073] More preferably, the upper cover 3 is a sheet metal part with a thickness of 2mm. The upper cover 3 is connected to the upper flange structure 101 by bolts, and a sealing gasket is also provided between the upper cover 3 and the upper flange structure 101.

[0074] like Figure 1 , Figure 11 As shown, the top of the cover 3 is provided with two handles 10 for easy disassembly and assembly; the top of the cover 3 is also equipped with an explosion-proof valve 11, the inlet height of which is higher than the design maximum liquid level of the immersion liquid, but lower than or level with the height of the top surface of the upper flange structure 101; by sharing the installation height space of the explosion-proof valve 11, it echoes the upper flange of the sheet metal welded box 1 to prevent the immersion liquid from overflowing.

[0075] like Figure 2 , Figure 15 As shown, the outer side of the housing 1 is also provided with an inlet 15, an outlet 16, an oil level indicator 12, a lifting point 13, and a battery management unit 14 (external BMU). The oil level indicator 12 is used to visually check the liquid level, color clarity, and presence of sediment, bubbles, or abnormalities in the immersion liquid inside the housing 1. The lifting point 13 is used for the lifting, transportation, and installation of the entire battery pack. The external BMU is connected to the module-less CCS7 for monitoring and managing the operating status of the battery modules. The inlet 15 and outlet 16 are connected to the coolant inlet and coolant outlet of the liquid cooling plate 4, respectively.

[0076] Preferably, the battery module is assembled using the CTP method, with individual cells directly inserted into the box and the entire box welded together, eliminating the need for end plates, clamps, insulating bases, and other structures; the individual cells 5 are connected to each other through a module-less CCS7 (cell connection system).

[0077] To address the issue of initial preload on individual cells, a compressible inter-cell buffer pad is added between the individual cells 5, and wedge-shaped blocks are added at both ends of the battery module to facilitate end-extension installation. The compressible inter-cell buffer pad can be a strip of foam, and the immersion liquid between cells can flow by vertically installing the strip of foam.

[0078] To prevent the battery cells from bouncing up and down, the bottom of the battery cell 5 is coated with polyurethane thermally conductive structural adhesive to achieve a reliable fixed connection with the bottom plate of the housing 1.

[0079] To prevent the battery module from shaking during transportation, insulating blocks 6 are installed on the top of multiple individual battery cells 5. The insulating blocks 6 are strip-shaped structures, also known as pressure strips, which serve to fix and constrain the battery cells. The two ends and the middle of the pressure strip are connected to the housing 1 by bolts. This pressure strip uses sheet metal bending parts and is coated with 0.5-1.5mm epoxy resin insulating protective glue. This pressure strip is easy to process and has low cost. The insulation protection meets DC4380V.

[0080] In summary, this application has at least the following advantages:

[0081] 1. To address the problem of uneven cell temperature in traditional technologies (the cell only dissipates heat from the bottom, resulting in a large temperature difference between the top and bottom), this application aims to reduce the temperature difference between the top and bottom, improve the cycle life of the cell, and at the same time, minimize the likelihood of thermal runaway and heat propagation. By adopting a non-flowing immersion method for the cell, which differs from the traditional bottom cooling solution, a liquid cooling plate radiator is placed in the middle of the battery module, forming a composite heat dissipation solution of "fully immersed + built-in liquid cooling plate", which realizes a 360° all-round heat exchange mode of the liquid cooling plate.

[0082] Furthermore, the liquid cooling plate is also equipped with fins to increase the heat exchange surface, effectively solving the problem of high heat generation and inability to dissipate heat in high-rate cells. This immersion heat dissipation structure has strong heat dissipation capacity and high safety performance, making the cell temperature more uniform and avoiding the problem of low temperature at the bottom and high temperature at the top in traditional heat dissipation. The temperature rise of the cells in the pack is low and the temperature difference is small. The immersion liquid is a hydrocarbon with good insulation properties. A large amount of immersion liquid directly wraps the cells, which can quickly absorb the huge heat released when the cells are thermally runaway, and the heat is quickly diffused through convection of the liquid cooling plate. This can avoid the risk of heat spread caused by thermal runaway of a single cell and greatly reduce the probability of thermal runaway of the entire pack.

[0083] 2. The immersion-type internally installed liquid-cooled finned heat sink promotes airflow. This heat dissipation solution allows the discharge rate of high-capacity, large-cell packs to be adjusted from 0.5P to 1P or even higher, meeting the stringent requirements for high-power response in scenarios such as frequency modulation, enabling the successful implementation of high-discharge-rate packs required for frequency modulation projects. Due to the improved heat exchange method in thermal management, the temperature rise and temperature difference of the pack are reduced, the temperature uniformity of the individual cells is improved, the pack cycle life is increased, and the fire protection issue within the pack is solved. The material compatibility and leakage prevention design of this immersion-type pack are particularly critical. This enclosure design and component sealing design avoid the risk of leakage, ensuring the safety and stability of the system in long-term operation.

[0084] 3. The pack uses hydrocarbon liquid (hydrocarbon synthesis agent) as the immersion fluid for heat dissipation. This medium has the characteristics of hydrocarbon liquid stability, high insulation performance, low cost, and good compatibility, effectively ensuring the safety of the system in long-term use. This hydrocarbon-based immersion fluid reduces the temperature difference of the cell body, enhances external heat dissipation, and reduces the temperature difference and temperature rise of the cells inside the immersion fluid. Ultimately, it not only improves the thermal runaway safety of the system, but also improves the cycle life and the consistency of the system's electrical performance. The immersion fluid adopts a full immersion method, which further reduces the risk of thermal runaway propagation and is safer. The internal immersion fluid flows, reducing the temperature difference between the top and bottom of the cell, resulting in a lower temperature difference within the same layer and more uniform heat dissipation. In addition, the hydrocarbon-based immersion fluid has been continuously verified in recent years, enhancing the compatibility of materials and approaching the goal of zero risk of thermal runaway. In addition to hydrocarbon liquid, more expensive fluorinated liquids can also be selected as immersion fluids.

[0085] 4. The liquid-cooled plate structure has two forms: the first is to use extruded aluminum profiles with externally brazed fins to make a liquid-cooled finned heat sink; the second is to use a harmonica tube as the main structure on the outside for liquid cooling circulation, with internally welded fins. The harmonica tube wall is thinner, making the overall liquid-cooled harmonica tube finned heat sink lighter and cheaper, while the strength of the heat dissipation structure in the middle is fully met.

[0086] The liquid-cooled finned heat sink, combined with the gap between individual battery cells, allows the temperature difference to drive internal circulation when the battery cell is working. This pack breaks through 52S and is a large pack with a length of 2200*width of 830.

[0087] 5. CTP Immersion Large Battery Pack: The pack module adopts the CTP method for assembly, with cells directly inserted into the box without clamps or end plates, reducing inter-module connections, making assembly more efficient, reducing parts, lowering costs, and improving connection reliability; this pack uses 1P 314AH large cells, manufactured in 84S mode, with an overall size exceeding 2200; during the development of this pack, material compatibility issues were resolved, and all materials underwent compatibility testing using hydrocarbon-based immersion oil;

[0088] 6. From an economic perspective, using sheet metal welded enclosures instead of extruded aluminum profile enclosures improves structural strength, enhances safety performance, and reduces costs. Sheet metal enclosures do not require molds, increasing product flexibility and saving on mold costs and other expenses.

[0089] 7. Immersion liquid internal circulation, microchannel liquid cooling plate heat dissipation, high energy storage rate pack: By setting a circulation pump in the tank, the internal immersion liquid circulation performance is increased, solving the problem of uneven heat distribution caused by low immersion thermal conductivity;

[0090] 8. By setting an upward-flipping structure on the top of the enclosure, an upward-flipping basin-type sheet metal welded immersion enclosure structure is formed: the top cover of the enclosure adopts a handle structure to solve the problem of installation and disassembly; at the same time, the upward-flipping structure and the top surface of the enclosure form a boss, which can effectively block and contain the immersion liquid that may leak, preventing it from overflowing and effectively solving the hidden dangers caused by large-area sealing leakage; in addition, an explosion-proof valve is also installed on the top of the top cover, the inlet height of which is higher than the design maximum liquid level of the immersion liquid, but lower than or level with the height of the top surface of the upward-flipping structure. By sharing the installation height space of the explosion-proof valve, and echoing the upward-flipping of the sheet metal welded enclosure, the overflow of the immersion liquid is further prevented, and the sealing safety of the system is improved.

[0091] 9. The outer side of the enclosure is also equipped with an inlet and an outlet, as well as an oil level indicator, lifting points, and an external battery management unit (BMU). The oil level indicator is used to visually check the liquid level, color clarity, and presence of sediment, bubbles, or other abnormalities in the immersion liquid inside the enclosure. The lifting points are used for the lifting, transportation, and installation of the entire battery pack. The external BMU is used to monitor and manage the operating status of the battery modules, which improves the reliability of the electronic system and facilitates maintenance and repair.

[0092] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A high-rate immersion safety battery pack system for energy storage, characterized in that, include: The enclosure includes a housing and a top cover. Inside the housing, at least two rows of battery modules are arranged. Vertically arranged liquid cooling plates are arranged between adjacent battery modules. The liquid cooling plates have coolant channels inside and are provided with coolant inlets and coolant outlets for connecting to an external cooling circulation system. The interior of the enclosure is filled with an immersion liquid to completely submerge the battery module and the liquid cooling plate. The immersion liquid absorbs the heat generated by the battery module. The liquid cooling plate exchanges heat with the immersion liquid after heat exchange and / or directly with the battery module, and establishes a temperature difference within the battery module. This temperature difference drives the immersion liquid to form a micro-circulation within the enclosure, and the heat is ultimately carried away by the circulating coolant inside the liquid cooling plate.

2. The high-rate immersion safety battery pack system for energy storage according to claim 1, characterized in that, The temperature difference-driven microcirculation specifically refers to: On either side of the liquid cooling plate, the immersion liquid closer to the liquid cooling plate has a lower temperature and flows downward, while the immersion liquid farther away from the liquid cooling plate has a higher temperature and flows upward, thereby forming a clockwise micro-circulation in the battery module area on the left side of the liquid cooling plate and a counterclockwise micro-circulation in the battery module area on the right side of the liquid cooling plate.

3. The high-rate immersion safety battery pack system for energy storage according to claim 1, characterized in that, Both sides of the liquid cooling plate are provided with finned structures, which extend into the immersion liquid; or... The liquid cooling plate is a harmonica tube type liquid cooling plate, including: a harmonica tube body, the inside of the tube body is provided with fin structures along its length, and the coolant flow channels are formed on both sides of the tube body corresponding to the fin structures.

4. The high-rate immersion safety battery pack system for energy storage according to claim 1, characterized in that, Each of the battery modules includes multiple individual battery cells arranged sequentially in the same direction, with gaps between adjacent individual battery cells forming a flow channel for the immersion liquid; The capacity of the individual battery cell is not less than 300Ah, and the battery pack system is configured to support a discharge rate of not less than 1C.

5. The high-rate immersion safety battery pack system for energy storage according to claim 4, characterized in that, The enclosure is formed by sheet metal welding. The interior of the box is provided with a middle beam arranged perpendicular to the liquid cooling plate. The top opening edge of the box is provided with an outward and upward extended flange structure. The flange structure and the top surface of the box form a boss. The top cover and the flange structure are connected by bolts, and a sealing gasket is provided between the top cover and the flange structure.

6. The high-rate immersion safety battery pack system for energy storage according to claim 5, characterized in that, The battery module is assembled using the CTP method, and its multiple individual cells are connected through a module-free CCS. Insulating blocks are installed on the top of multiple individual battery cells.

7. The high-rate immersion safety battery pack system for energy storage according to claim 6, characterized in that, The battery module is provided with wedge-shaped blocks at both ends, and a compressible inter-cell buffer pad is provided between adjacent individual cells. A polyurethane thermally conductive structural adhesive is applied between the bottom of the individual battery cell and the bottom plate of the housing. The insulating pressure block is a strip-shaped pressure strip, and both ends and the middle of the pressure strip are connected to the box body by bolts; the pressure strip is a sheet metal bending part, and its exterior is coated with an epoxy resin insulating layer.

8. The high-rate immersion safety battery pack system for energy storage according to claim 6, characterized in that, The top of the cover is equipped with a handle and an explosion-proof valve.

9. The high-rate immersion safety battery pack system for energy storage according to claim 1, characterized in that, The outer side of the housing is provided with an inlet and an outlet that are respectively connected to the coolant inlet and coolant outlet, as well as an oil level sight glass, a lifting point, and a battery management unit. The oil level sight glass is used to observe the state of the immersion liquid, the lifting point is used for lifting, transporting and installing the entire battery pack, and the battery management unit is used to manage the operating status of the battery modules.

10. The high-rate immersion safety battery pack system for energy storage according to claim 1, characterized in that, The immersion solution is a hydrocarbon liquid or a fluorinated liquid; The tank is also equipped with a circulation pump to drive the immersion liquid to circulate.

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