Submerged liquid-cooled energy storage battery pack

Abstract

The utility model discloses a kind of immersion liquid cooling energy storage battery pack, including box, upper cover, battery module and immersion liquid;Its core is in that box bottom is provided with independent cold plate, and cold plate and box are detachable split type structure;Sealed cooling liquid flow channel is equipped in the inside of cold plate, for circulating into coolant;Box is filled with immersion liquid, for immersing battery module;The circulation in cooling liquid flow channel is physically isolated with the immersion liquid in box;The utility model is separated by split type design, realizes the separation of coolant circulation system and immersion liquid system, significantly reduces manufacturing cost and maintenance cost, improves the flexibility and reliability of system, while guaranteeing the high efficiency, uniform heat dissipation performance of battery pack.

Description

Technical Field

[0001] This application relates to the field of energy storage battery technology, specifically to an immersion liquid-cooled energy storage battery pack. Background Technology

[0002] As the energy density of energy storage battery systems continues to increase, battery heat dissipation has become a key factor restricting their safety and lifespan. Immersion liquid cooling technology, by directly immersing the battery module in an insulating coolant, can achieve efficient heat dissipation and excellent temperature uniformity, and is currently an advanced thermal management solution.

[0003] Existing immersion liquid-cooled battery packs mostly adopt an integrated design, where the casing itself serves as the liquid cooling plate, and the cooling channels are inseparable from the casing structure. This design has the following inherent drawbacks: First, the casing must be made of the same thermally conductive metal material as the cooling plate (such as aluminum alloy), resulting in high material costs; second, the casing structure is complex, often requiring customized mold production, leading to high manufacturing costs and long lead times; third, once the internal cooling channels corrode or leak, the entire casing must be replaced, resulting in extremely high maintenance costs, and it cannot adapt to different types of cooling channels, exhibiting poor flexibility.

[0004] Therefore, there is an urgent need in this field for a new battery pack structure that can maintain the advantages of efficient heat dissipation of immersion liquid cooling while overcoming the inherent defects of integrated design. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide an immersion liquid-cooled energy storage battery pack. By designing the cold plate and the housing as a separate structure, the physical isolation between the coolant circulation and the immersion liquid is achieved, thereby solving the problems of high cost, difficult maintenance, and poor flexibility in existing technologies.

[0006] To achieve the above objectives, this utility model provides the following technical solution: An immersion-type liquid-cooled energy storage battery pack includes a housing, a housing cover, battery modules, and an immersion liquid. Its core improvement lies in: The bottom of the box is equipped with an independent cold plate, and the cold plate and the box are detachable and separate structures; The cold plate has a sealed coolant flow channel inside, and the coolant flow channel has an inlet and an outlet connected to an external circulation system for circulating coolant. The box is filled with the immersion liquid for immersing the battery module; The coolant circulation in the coolant channel is physically isolated from the immersion liquid in the tank, forming two independent heat exchange systems.

[0007] Preferably, the cold plate comprises a flat plate and a flow channel plate, wherein the flat plate and the flow channel plate are welded and sealed to form the coolant flow channel. This modular design facilitates specialized production and quality control of the cold plate.

[0008] Preferably, the coolant flow channels are arranged in an S-shape and include multiple parallel branch channels. This flow channel design can increase the heat exchange area and improve the turbulence of the coolant, thereby enhancing the heat exchange efficiency.

[0009] Preferably, the cold plate is connected to the housing by fasteners (such as nuts and bolts). This connection method is robust and reliable, and facilitates the installation and removal of the cold plate.

[0010] Preferably, the battery module is disposed above the cold plate, and a thermally conductive structure, such as thermally conductive adhesive coated between the battery module and the cold plate, is provided. This structure ensures that the heat generated at the bottom of the battery module can be efficiently conducted to the cold plate.

[0011] Preferably, the tank body is provided with an immersion liquid inlet and an overflow prevention outlet, both of which are equipped with one-way valves. The immersion liquid inlet is located at the bottom of the tank body for easy liquid injection and air bubble removal; the overflow prevention outlet is located at the top of the tank body to prevent excessive liquid level and leakage due to thermal expansion.

[0012] Preferably, the cold plate is made of aluminum to ensure excellent thermal conductivity; the housing is made of galvanized steel plate to balance structural strength, corrosion resistance and low cost.

[0013] Preferably, the immersion liquid is an insulating and cooling medium such as hydrocarbon-based oil, fluorinated liquid, or silicone oil.

[0014] This utility model has the following beneficial effects: Significantly reduced costs: The enclosure can be manufactured using low-cost standard galvanized steel sheets through sheet metal processing, eliminating the need for molds and greatly reducing material and manufacturing costs. Cold-rolled steel sheets, as independent components, can be standardized and mass-produced.

[0015] Extremely convenient to maintain: When the coolant flow channel inside the cold plate leaks or is damaged, you only need to disassemble and replace the cold plate, without scrapping the entire expensive housing, which greatly reduces maintenance costs and downtime.

[0016] Flexible design and strong adaptability: The split design allows the cooling plate to be optimized and iterated independently of the cabinet. Cooling plates with different flow channel forms (such as S-shaped, parallel branch, etc.) can be flexibly replaced according to different heat dissipation requirements, improving the product's versatility and upgradeability.

[0017] High and uniform heat dissipation efficiency: The bottom of the battery module is actively cooled by circulating coolant in the cold plate, while the sides of the battery module are immersed in immersion liquid for heat dissipation. This forms a dual high-efficiency cooling mode of "active cooling at the bottom + immersion heat dissipation around the body", which ensures excellent temperature uniformity of the battery pack. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of the battery pack according to an embodiment of this application.

[0019] Figure 2 This is a schematic diagram showing the connection between the battery pack cold plate and the housing in an embodiment of this application.

[0020] Figure 3 This is a schematic diagram of the cold plate structure in an embodiment of this application, showing the welding relationship between the flat plate and the flow channel plate.

[0021] Figure 4 This is a schematic diagram of the coolant flow channel layout in an embodiment of this application.

[0022] Figure 5 This is a three-dimensional structural diagram of the battery pack according to an embodiment of this application, excluding the top cover of the casing.

[0023] Explanation of the labels in the diagram: 1-Box body; 11-Immersion liquid inlet; 12-Overflow prevention port; 13-One-way valve; 14-Heat-conducting structure; 2-Top cover of the box; 3-Battery module; 5-Cold plate; 51-Flat plate; 52-Flow channel plate; 53-Coolant flow channel; 54-Inlet; 55-Outlet; 6-Fasteners. Detailed Implementation

[0024] The following embodiments are described to aid in understanding this application. These embodiments are not, and should not be, construed in any way as limiting the scope of protection of this application.

[0025] In the following description, those skilled in the art will recognize that throughout this discussion, components may be described as individual functional units (which may include subunits), but those skilled in the art will recognize that various components or portions thereof may be divided into individual components or may be integrated together (including integrated within a single system or component).

[0026] Furthermore, the connection between components or systems is not intended to be limited to a direct connection; on the contrary, data between these components may be modified, reformatted, or otherwise altered by intermediate components. Additionally, other or fewer connections may be used. It should also be noted that the terms "connection," "link," or "input" should be understood to include direct connections, indirect connections via one or more intermediate devices, and wireless connections.

[0027] In the process of designing and implementing this application, the applicant conducted an in-depth review and analysis of existing submerged liquid-cooled battery packs. The applicant recognized that the commonly used integrated structure, which combines the cooling channels with the casing wall, while structurally compact, also leads to high material costs, complex manufacturing processes, and, most critically, extremely high and inconvenient maintenance costs after damage to the cooling channels. The root of these drawbacks lies in forcibly coupling two systems with vastly different functions and operating conditions—a pressurized circulating cooling system and a static, atmospheric-pressure submerged liquid container—to a single component.

[0028] Based on this understanding, the applicant conceived a core idea: could the cooling function be "decoupled" from the structural load-bearing function, and the above problems be solved through a split design? This idea became the starting point for this application's exploration.

[0029] To verify and realize this idea, the applicant conducted the following steps of exploration and design: First, to address the core "separate" issue, the applicant designed an independent cold plate 5 with a sealed coolant flow channel 53 inside, separating it from the housing 1 used to house the battery module 3 and the immersion liquid. This design allows the coolant to form a closed loop inside the cold plate 5, physically isolating it from the immersion liquid inside the housing 1, thus creating two independent heat exchange systems from the outset.

[0030] Subsequently, the applicant needed to address the issues of "connection" and "heat conduction" after the components were separated. To ensure a secure connection between the cold plate 5 and the housing 1, and to facilitate maintenance, the applicant opted for a detachable connection using fasteners 6 such as nuts and bolts. Simultaneously, to avoid sacrificing heat dissipation efficiency due to the separate structure, the applicant creatively incorporated a heat-conducting structure 14 between the battery module 3 and the cold plate 5, for example, by applying a high-performance thermally conductive adhesive, thus establishing an efficient heat conduction path from the heat source to the cold source.

[0031] After resolving the basic architectural issues, the applicant further optimized each subsystem to maximize the advantages of the modular design. For the cold plate 5, the applicant designed it as a module welded from a flat plate 51 and a flow channel plate 52, optimizing its internal flow channels into an S-shape with multiple parallel branches to significantly improve heat exchange efficiency. For the housing 1, the applicant fully utilized its function of no longer needing to handle coolant circulation, selecting lower-cost, high-strength galvanized steel sheets for manufacturing, and employing a simple sheet metal bending and welding process, significantly reducing material and manufacturing costs.

[0032] Ultimately, through the aforementioned systematic exploration and design, the applicant successfully constructed a complete technical solution centered on the "separate cold plate 5 and casing 1". This solution not only achieved the initially set goals of low cost and easy maintenance, but also brought unexpected technical effects such as improved heat dissipation efficiency and wider adaptability due to its modular design, ultimately forming the immersion liquid-cooled energy storage battery pack shown in this application.

[0033] Therefore, the applicant proposes an immersion liquid-cooled energy storage battery pack, including a housing 1, a housing cover 2, battery modules 3, and an immersion liquid. Its core improvement lies in: The bottom of the housing 1 is provided with an independent cold plate 5, and the cold plate 5 and the housing 1 are detachable and separate structures. The cold plate 5 is provided with a sealed coolant flow channel 53. The coolant flow channel 53 is provided with an inlet 54 and an outlet 55 connected to an external circulation system for circulating coolant. The housing 1 is filled with the immersion liquid, which is used to immerse the battery module 3. The coolant circulation in the coolant channel 53 is physically isolated from the immersion liquid in the tank 1, forming two independent heat exchange systems.

[0034] Compared to the integrated design of the housing 1 and cold plate 5 in existing technologies, this application uses an innovative split structure to physically isolate the pressurized coolant circulation system (cold plate 5 flow channel) from the atmospheric pressure immersion liquid static heat dissipation system (housing 1). This brings multiple benefits: First, the housing 1 no longer needs to use expensive thermally conductive metals (such as aluminum alloy) to manufacture the flow channel, and can use lower-cost galvanized steel sheets, significantly reducing material costs; second, the cold plate 5 can be produced in a standardized and modular manner, while the housing 1 can be manufactured using simple sheet metal processes without the need for mold making, reducing manufacturing difficulty and costs; third, when the cooling flow channel leaks or is damaged, only the cold plate 5 needs to be replaced, without scrapping the entire housing 1, greatly simplifying the maintenance process and reducing maintenance costs and time.

[0035] In some embodiments, the cold plate 5 includes a flat plate 51 and a flow channel plate 52, wherein the flat plate 51 and the flow channel plate 52 are welded and sealed to form the coolant flow channel 53. This modular design facilitates specialized production and quality control of the cold plate 5.

[0036] The design also modularizes the cold plate 5 itself. Compared to the complex cold plate 5 that is milled or cast as a whole, this structure, which is welded from the flat plate 51 and the flow channel plate 52, simplifies the manufacturing process of individual parts, facilitates specialized production and strict quality control (such as sealing tests), thereby further reducing its manufacturing cost and improving production efficiency and yield while ensuring the performance of the cold plate 5.

[0037] In some embodiments, the coolant flow channel 53 is arranged in an S-shape and includes multiple parallel branch channels. This flow channel design can increase the heat exchange area and improve the turbulence of the coolant, thereby enhancing the heat exchange efficiency.

[0038] The flow channel design is optimized for the split-type cold plate 5. The S-shaped arrangement extends the flow path and time of the coolant within the cold plate 5, while multiple parallel branch channels disperse the coolant flow, collectively increasing the total heat exchange area. This design significantly improves the turbulence of the coolant, breaks down the boundary layer, and thus greatly enhances the efficiency of the cold plate 5 in absorbing heat from the bottom of the battery module 3, ensuring rapid cooling of the core heat source area of ​​the battery pack.

[0039] In some embodiments, the cold plate 5 is connected to the housing 1 by fasteners 6 (such as nuts or bolts). This connection method is robust and reliable, and facilitates the installation and removal of the cold plate 5.

[0040] The use of fastener 6 is key to achieving the "detachable" modular structure. Compared to permanent connections such as welding, this connection is robust and reliable while also providing the structure with great flexibility. It makes the installation and removal of the cold plate 5 very simple, providing a foundation for quick on-site replacement and maintenance of the cold plate 5, truly realizing the core value of the modular design for easy maintenance.

[0041] In some embodiments, the battery module 3 is disposed above the cold plate 5, and a thermally conductive structure 14, such as thermally conductive adhesive coated between the battery module 3 and the cold plate 5, is provided. This structure ensures that the heat generated at the bottom of the battery module 3 can be efficiently conducted to the cold plate 5.

[0042] This design establishes an efficient heat conduction path between battery module 3 (the main heat source) and cold plate 5 (the active cooling component). Thermally conductive adhesive fills the microscopic gaps at the contact surface, eliminating air (a poor conductor of heat) and significantly reducing contact thermal resistance. This allows heat generated at the bottom of battery module 3 to be conducted unimpeded and efficiently to cold plate 5, where it is carried away by the coolant within the flow channels, ensuring the effectiveness of the bottom active cooling system in the split structure.

[0043] In some embodiments, the tank 1 is provided with an immersion liquid inlet 11 and an overflow port 12, and both the immersion liquid inlet 11 and the overflow port 12 are provided with a one-way valve 13. The immersion liquid inlet 11 is located at the lower part of the tank 1 to facilitate liquid injection and air bubble removal; the overflow port 12 is located at the upper part of the tank 1 to prevent excessive liquid level and leakage due to thermal expansion.

[0044] This immersion fluid management scheme improves the overall system's sealing and safety. The immersion fluid inlet 11 is located at the bottom for easy filling and air bubble removal, while the overflow port 12 is located at the top and equipped with a one-way valve 13. This effectively prevents liquid leakage or deformation of the tank 1 due to excessive filling or thermal expansion of the immersion fluid. It also prevents external air and contaminants from entering, ensuring the insulation performance of the immersion fluid and the long-term reliability of the system.

[0045] In some embodiments, the cold plate 5 is made of aluminum to ensure excellent thermal conductivity; the housing 1 is made of galvanized steel plate to balance structural strength, corrosion resistance and low cost.

[0046] This material selection is an optimized choice based on the split structure. The cooling plate 5 continues to use aluminum, which has excellent thermal conductivity, focusing on efficient heat dissipation; while the enclosure 1 uses galvanized steel, which has high structural strength, corrosion resistance, and low cost, focusing on load-bearing and protection. This differentiated application of materials, each with its own function, optimizes material costs while ensuring the system's heat dissipation performance, directly demonstrating the cost advantages of the split design.

[0047] In some embodiments, the immersion liquid is an insulating and cooling medium such as hydrocarbon-based oil, fluorinated liquid, or silicone oil.

[0048] Choosing a suitable insulating cooling medium as the immersion fluid ensures the electrical safety of battery module 3 when it is submerged. These media have good insulation, chemical stability, and thermal conductivity, and can safely and directly contact the surface of the battery cells. They achieve uniform heat dissipation on all sides of the battery through natural convection or slight flow, complementing the active cooling at the bottom and jointly ensuring the temperature uniformity of the battery pack.

[0049] Example like Figures 1 to 5As shown, this embodiment provides an immersion liquid-cooled energy storage battery pack. The battery pack includes a housing 1 made of galvanized steel sheet by welding. The top of the housing 1 is sealed to the housing cover 2 by a sealing ring to form a closed shell.

[0050] A separate cooling plate 5 is fixedly mounted on the bottom of the housing 1 using fasteners 6. The fasteners 6 are nuts. The cooling plate 5 is welded and sealed from a 3003 aluminum alloy flat plate 51 and a flow channel plate 52, forming a sealed coolant flow channel 53 inside. This coolant flow channel 53 is generally S-shaped and splits into four parallel branches in the central area to enhance heat exchange. The portion of the cooling plate 5 extending beyond the front panel of the housing 1 has an inlet 54 and an outlet 55, which are connected to an external coolant circulation system (not shown) via quick-connect tubing.

[0051] The battery module 3 is installed inside the housing 1. The battery module 3 is mounted on the mounting strip at the bottom of the housing 1 via connectors at both ends. A layer of thermally conductive adhesive, approximately 0.5 mm thick, is applied between the bottom surface of the battery module 3 and the flat plate 51 of the cold plate 5 as a thermally conductive structure 14 to ensure good heat conduction.

[0052] The housing 1 is filled with a hydrocarbon-based immersion liquid, the liquid level of which completely submerges the battery module 3. An immersion liquid inlet 11 is located at one corner of the lower part of the housing 1, and an overflow port 12 is located at the upper diagonal. Both the inlet and outlet are equipped with one-way valves 13. The overflow port 12 is connected to an overflow prevention pipe that extends into the housing 1, with its opening below the top height of the housing 1.

[0053] During operation, the external coolant circulates within the channels of the cold plate 5, carrying away the battery heat transferred through the thermally conductive adhesive. Simultaneously, the immersion liquid directly contacts all surfaces of the battery module 3, further equalizing the temperature through convection heat transfer. The two heat exchange systems work independently yet collaboratively, achieving efficient and uniform heat dissipation.

[0054] When the cold plate 5 needs maintenance or replacement, simply drain the external cooling pipes and unscrew the nuts to remove the cold plate 5 from the housing 1. The operation is simple and the maintenance cost is low.

[0055] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An immersion liquid-cooled energy storage battery pack, comprising a housing (1), a housing cover (2), a battery module (3), and an immersion liquid, characterized in that: The bottom of the housing (1) is provided with an independent cold plate (5), and the cold plate (5) and the housing (1) are detachable separate structures; the cold plate (5) is provided with a sealed coolant channel (53), and the coolant channel (53) is provided with an inlet (54) and an outlet (55) connected to an external circulation system for circulating coolant; the housing (1) is filled with the immersion liquid for immersing the battery module (3); wherein, the coolant circulation in the coolant channel (53) and the immersion liquid in the housing (1) are physically isolated from each other.

2. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The cold plate (5) includes a flat plate (51) and a flow channel plate (52), and the flat plate (51) and the flow channel plate (52) are welded and sealed to form the coolant flow channel (53).

3. The submersible liquid-cooled energy storage battery pack according to claim 1 or 2, characterized in that, The coolant flow channel (53) is arranged in an S-shape and includes multiple parallel branch channels.

4. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The cold plate (5) is connected to the housing (1) by fasteners (6).

5. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The battery module (3) is disposed above the cold plate (5), and a heat-conducting structure (14) is provided between the battery module (3) and the cold plate (5).

6. The immersion liquid-cooled energy storage battery pack according to claim 5, characterized in that, The thermally conductive structure (14) is a thermally conductive adhesive coated between the battery module (3) and the cold plate (5).

7. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The housing (1) is provided with an immersion liquid inlet (11) and an overflow port (12), and both the immersion liquid inlet (11) and the overflow port (12) are provided with a one-way valve (13).

8. The immersion liquid-cooled energy storage battery pack according to claim 7, characterized in that, The immersion liquid inlet (11) is located at the lower part of the tank (1), and the overflow port (12) is located at the upper part of the tank (1).

9. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The cold plate (5) is made of aluminum, and the box body (1) is made of galvanized steel plate.

10. The immersion liquid-cooled energy storage battery pack according to claim 1, characterized in that, The immersion liquid is a hydrocarbon-based oil, a fluorinated liquid, or a silicone oil.

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