A two-phase immersion battery cooling system

Abstract

The application relates to a two-phase immersion battery cooling system and belongs to the technical field of battery thermal management. The system comprises a condenser, the condenser comprising a condensing pipeline and fins arranged outside the condensing pipeline for heat dissipation, the heat dissipation fins being arc-shaped inclined fins; an immersion cavity, the immersion cavity being a sealed container, the top of the immersion cavity being communicated with the condenser, the inside of the immersion cavity being filled with cooling liquid and containing a battery module wrapped by double-layer nets; and a bottom sealing base, the bottom sealing base being sealingly connected with the bottom of the immersion cavity. The arc-shaped inclined fins increase the heat exchange area, the gradually-changing-pitch groove structure optimizes the steam flow path and heat exchange working condition, the double-layer net heat dissipation structure strengthens heat transfer, and the battery heat dissipation rate is effectively improved.

Description

Technical Field

[0001] This application relates to the field of battery thermal management technology, and in particular to a two-phase immersion battery cooling system. Background Technology

[0002] Lithium-ion batteries generate a significant amount of heat during high-power charging and discharging. If this heat cannot be dissipated in time, the battery temperature will rise, affecting its cycle life, charging and discharging efficiency, and safety. Two-phase immersion cooling technology is widely used in lithium-ion battery cooling applications due to its advantages such as high heat exchange efficiency and good temperature uniformity.

[0003] Existing two-phase immersion battery cooling systems typically include a container holding the battery, a coolant immersing the battery, and a top condenser, which is cooled by an external water cooling system. However, existing systems have significant shortcomings: detailed geometric design of the condenser coils is lacking, resulting in limited heat exchange area and efficiency; the battery exterior lacks targeted heat dissipation enhancement structures, leading to a slow heat transfer rate that fails to meet the rapid heat dissipation requirements of high-power lithium-ion batteries, thus limiting the system's cooling performance and applicability. Summary of the Invention

[0004] Based on this, this application provides a two-phase immersion battery cooling system to improve the heat dissipation efficiency of the battery.

[0005] To address the above problems, the present invention provides a two-phase immersion battery cooling system, comprising: a condenser, the condenser including condensation pipes and fins disposed outside the condensation pipes for heat dissipation, the fins being arc-shaped inclined heat dissipation fins;

[0006] The immersion chamber is a sealed container with its top connected to the condenser. It is filled with coolant and contains a battery module wrapped in a double-layer mesh.

[0007] The bottom sealing base is sealed to the bottom of the immersion chamber.

[0008] Furthermore, grooves are formed between adjacent fins in the fins, and the spacing between the grooves gradually decreases from the top to the root of the groove.

[0009] Furthermore, the double-layer mesh surrounding the battery module includes a fine wire mesh and a coarse wire mesh. The fine wire mesh is tightly fitted to the battery module, while the coarse wire mesh is located outside the fine wire mesh, increasing the contact area with the coolant and accelerating the transfer of heat to the coolant.

[0010] Furthermore, the double-layer mesh extends along the circumference and axis to form a spiral mesh, interlocking, entwining or fixedly connecting with each other at each intersection point to form a stable mesh node.

[0011] Furthermore, a pressure measuring hole is provided on the immersion chamber at a position corresponding to the condenser inlet, and a pressure gauge is used to monitor the pressure changes in the immersion chamber in real time.

[0012] Furthermore, it also includes a solenoid valve installed at the condenser inlet, which is matched with the pressure gauge. The solenoid valve is adjusted according to the pressure in the immersion chamber to control the liquid inlet of the condenser, dynamically adjust the cooling intensity, and ensure the temperature and pressure in the immersion chamber are stable.

[0013] Furthermore, the condenser consists of at least two parallel condensing pipes, with fins surrounding the outer wall of the condensing pipes.

[0014] Furthermore, it also includes a U-shaped connecting pipe, which connects to both ends of the condenser pipe to form a continuous meandering pipe, so as to achieve uniform distribution of cooling liquid in the condenser and extend the flow path of liquid in the condenser.

[0015] Furthermore, the battery module is composed of at least two cylindrical batteries, and the overall shape is a rectangular block. During operation, the battery module generates heat, which is quickly transferred to the surrounding coolant through the double-layer mesh on the surface of the battery module. After absorbing the heat, the coolant undergoes a phase change and forms steam.

[0016] Furthermore, the steam rises to the condenser area and comes into contact with the pipes and fins of the condenser. The cooling liquid in the condenser carries away the heat of the steam through the pipe walls and fins. The steam undergoes a phase change and re-condenses into cooling liquid before flowing back into the immersion chamber to participate in the heat exchange cycle again.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The arc-shaped inclined fins of the present invention increase the heat exchange area, the groove structure with gradually varying spacing optimizes the steam flow path and heat exchange conditions, and the continuous meandering pipe arrangement prolongs the residence time of the cooling medium, which significantly improves the heat exchange efficiency of the condenser.

[0019] (2) The fine wire mesh of the present invention is closely attached to the battery module, which quickly dissipates the heat on the battery surface. The coarse wire mesh expands the contact area with the coolant, which accelerates the transfer of heat to the coolant. The heat transfer is enhanced by the double-layer mesh heat dissipation structure, which effectively improves the heat dissipation rate of the battery.

[0020] (3) The present invention can adjust the condenser water flow in real time through the synergistic action of pressure gauge and solenoid valve, realize dynamic control of cooling system, ensure that battery is always in a suitable temperature environment, and protect battery performance and safety. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the cooling system structure according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the battery immersion cavity, external interface, and base according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the condenser structure according to an embodiment of the present invention;

[0024] Figure 4 This is a partial schematic diagram of the spiral fins in an embodiment of the present invention;

[0025] Figure 5 This is a side view of the condenser according to an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the fin cross-sectional structure according to an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of a cylindrical lithium battery structure wrapped with a double-layer mesh, according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the top spiral structure of the lithium battery module according to an embodiment of the present invention;

[0029] Figure 9 For the present invention Figure 7 A schematic diagram of the battery grid structure in section A;

[0030] Wherein: 4-base; 11-condenser pipe; 12-fin; 13-groove; 14-U-shaped connecting pipe; 2-immersion cavity; 21-pressure gauge; 22-solenoid valve; 3-battery module; 31-fine wire mesh; 32-coarse wire mesh. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the scope of the present application.

[0032] This application relates to a two-phase immersion battery cooling system, such as Figure 1-9 As shown, it includes:

[0033] The condenser includes a condenser pipe 11 and fins 12 disposed outside the condenser pipe 11 for heat dissipation. The fins 12 are arc-shaped inclined heat dissipation fins.

[0034] Immersion chamber 2 is a sealed container with its top connected to condenser 1. It is filled with coolant and contains battery module 3 wrapped in double mesh.

[0035] The bottom sealing base 4 is sealed to the bottom of the immersion chamber 2.

[0036] The arc-shaped inclined fins 12 of this invention increase the heat exchange area, and the grooves 13 with gradually varying spacing optimize the steam flow path and heat exchange conditions. The double-layer mesh heat dissipation structure enhances heat transfer and effectively improves the battery heat dissipation rate. Specifically, due to the surface tension of the coolant, many cavities are formed between the interlaced metal meshes and between the metal meshes and the battery. These cavities are numerous and small in diameter. During the process of heating the coolant until it boils, these cavities can greatly enhance the boiling of the coolant and the intensity of heat exchange.

[0037] In one embodiment of this application, a spiral inner rib is provided inside the condenser pipe 11. The height of the inner rib is 1 / 8 to 1 / 10 of the inner diameter of the pipe, and the spiral helix angle is 30° to 45°. The inner rib and the arc-shaped inclined fins 12 outside the pipe form an inner and outer double disturbance structure. The coolant inside the pipe is guided by the inner rib to form a spiral flow, while the steam outside the pipe achieves directional flow through the grooves 13 between the fins 12. Through the inner and outer double disturbance structure design of the condenser, the steam condensation heat transfer coefficient is increased by more than 30%, and the thermal resistance is reduced to below 0.025℃·cm² / W.

[0038] As one embodiment of this application, a groove 13 is formed between adjacent fins 12. Multiple grooves 13 are provided along the length of the condenser pipe 11. The grooves 13 are generally V-shaped, that is, the spacing between the grooves 13 gradually decreases from the top to the root of the groove 13.

[0039] For example, the root of the groove 13 near the condenser pipe 11 adopts a narrow and deep multi-stage stepped shape. Here, the coolant film is relatively thick, and the stepped structure effectively captures and drains the coolant in sections, reducing the film thickness and lowering thermal resistance. The middle of the groove 13 transitions into a wavy or serrated shape to disturb airflow, disrupt the air boundary layer, and provide capillary attraction for the coolant, assisting it in converging towards the center. The top of the groove 13, near the edge of the fin 12, is designed as a wide and shallow drainage channel, pointing towards the edge of the fin 12, to throw the coolant collected in the center out of the fin 12, preventing coolant accumulation in the edge area of ​​the fin 12. This achieves zoned control of coolant generation, collection, and discharge, reducing thermal resistance and improving heat exchange efficiency.

[0040] Traditional evenly spaced grooves are prone to problems such as excessive pressure drop due to high inlet flow velocity and insufficient heat exchange due to decreased outlet flow velocity. This invention employs a gradually spaced groove structure, which uses computer simulation to model the steam flow characteristics at different heating stages, achieving a dynamic adaptation design for the groove spacing. A smaller spacing is used in the core area where the heat source is concentrated, accelerating the steam flow velocity to quickly remove high heat; the spacing gradually increases in the edge areas away from the heat source, reducing flow resistance while ensuring sufficient heat exchange. This design not only reduces steam flow resistance by more than 25%, but also effectively solves the problem of localized overheating and overall inefficiency in traditional structures, keeping the temperature difference between different areas of the battery module 3 within ±2℃, meeting the stringent temperature uniformity requirements of high-end battery systems.

[0041] For example, the fins 12 are made of a graded functional material. The fins 12 near the condenser pipe 11 are made of a high thermal conductivity material, preferably a copper or graphene composite material, to ensure that heat is rapidly dissipated from the condenser pipe 11. The middle layer of fins 12 uses a high-strength and hydrophilic material to ensure structural stability and promote liquid film spreading. The outermost layer of fins 12 uses a superhydrophobic material, preventing condensate from adhering to the top of the fins 12, causing it to quickly form droplets and roll off. This achieves strong thermal conductivity at the root and rapid drainage at the top, resolving the contradiction between thermal conductivity and drainage.

[0042] As one embodiment of this application, the double-layer mesh surrounding the battery module 3 includes a fine wire mesh 31 and a coarse wire mesh 32. The fine wire mesh 31 is tightly fitted to the battery module 3, while the coarse wire mesh 32 is located outside the fine wire mesh 31, increasing the contact area with the coolant and accelerating heat transfer to the coolant. The inner fine wire mesh 31 is responsible for heat absorption and conduction, while the outer coarse wire mesh 32 is responsible for heat dissipation. Heat is efficiently transferred from the inside to the outside through the contact points between the two meshes.

[0043] For example, the mesh size of the fine wire mesh 31 is smaller than that of the coarse wire mesh 32. The denser mesh ensures more contact points with the battery module 3's outer casing, efficiently transferring heat generated by the battery to the fine wire mesh 31. The fine wire mesh 31 also allows localized hot spots on the battery surface to be quickly diffused across the entire mesh surface, preventing heat accumulation and achieving initial lateral heat balance. The coarse wire mesh 32, placed outside the fine wire mesh 31, increases the exposed metal surface in the coolant, allowing the coolant to directly and quickly carry away heat as it flows over it. Furthermore, the larger mesh size and the wire itself disturb the flowing coolant, changing it from laminar to turbulent flow, more effectively disrupting the insulating effect of the coolant boundary layer and enhancing convective heat transfer efficiency. In addition, the coarse wire mesh 32 provides better structural rigidity and protection for the entire enclosure layer, resisting potential external pressure or impact.

[0044] As one embodiment of this application, the double-layer mesh extends circumferentially and axially to form a spiral grid. At each intersection, the mesh interlocks, wraps around, or is fixedly connected to form stable mesh nodes, creating a continuous, rhomboid or parallelogram-like mesh texture with rounded edges across the entire mesh surface. This spiral weaving method gives the mesh a certain degree of axial extensibility and radial elasticity, facilitating its installation on the battery module 3 and adapting to the minute thermal expansion and contraction of the battery during charging and discharging. Furthermore, the spiral grid guides the flowing coolant, causing it to rotate along the spiral path, avoiding dead zones and further improving heat dissipation uniformity.

[0045] Furthermore, the long axis of the grid forms an angle of 15°-20° with the axial direction of the battery module 3, and micro-guide vanes are set at the grid intersections. The guide vanes are inclined at 30° with the grid plane to guide the coolant to form a spiral upward flow.

[0046] As one embodiment of this application, a pressure measuring hole is provided on the immersion chamber 2 at a position corresponding to the condenser inlet, and the pressure change in the immersion chamber 2 is monitored in real time by a pressure gauge 21.

[0047] As one embodiment of this application, it also includes a solenoid valve 22, which is installed at the condenser inlet and is matched with the pressure gauge 21. The solenoid valve 22 is adjusted according to the pressure in the immersion chamber 2 to control the liquid inlet of the condenser, dynamically adjust the cooling intensity, and ensure the temperature and pressure in the immersion chamber 2 are stable.

[0048] For example, based on the pressure signal, the solenoid valve 22 can be adjusted manually or by a controller to control the water inlet flow to the condenser. For example, the controller uses pressure as the primary control signal, while also incorporating temperature, flow rate, and vibration as auxiliary correction parameters. When a severe pressure fluctuation accompanied by high-frequency vibration is detected, the proportional gain is automatically reduced and the derivative action is increased to suppress oscillations, improve stability, and avoid frequent opening and closing or oscillation of the solenoid valve 22 near the critical point due to sensitivity to a single parameter.

[0049] As one embodiment of this application, the condenser comprises at least two parallel condensing pipes 11, with fins 12 surrounding the outer wall of the condensing pipes 11. Exemplarily, the main body of the condenser is designed to consist of six parallel condensing pipes 11. It also includes a U-shaped connecting pipe 14, which connects to both ends of the condensing pipes 11 to form a U-shaped connecting pipe 14, achieving uniform distribution of the cooling liquid within the condenser and extending the flow path of the liquid within the condenser.

[0050] For example, a flow distributor is added at the connection between the U-shaped connecting pipe 14 and the condenser pipe 11. The flow distributor adopts a porous medium diversion structure inside, and the porosity changes gradient along the flow direction to control the flow deviation between the condenser pipes 11 within ±5%.

[0051] As one embodiment of this application, the battery module 3 is composed of at least two cylindrical batteries and has an overall rectangular block shape. During operation, the battery module 3 generates heat, which is quickly transferred to the surrounding coolant through the double-layer mesh on the surface of the battery module 3. After absorbing the heat, the coolant undergoes a phase change and forms steam.

[0052] As one embodiment of this application, steam rises to the condenser area and comes into contact with the pipes and fins 12 of the condenser. The cooling liquid in the condenser carries away the heat of the steam through the pipe walls and fins 12. After the steam undergoes a phase change and re-condenses into cooling liquid, it flows back to the immersion chamber 2 and participates in the heat exchange cycle again.

[0053] It should be noted that, in this application, "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the method, article, or apparatus that includes that element.

[0054] In the description of this application, unless otherwise expressly defined, terms such as setting, design, installation, and connection should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0055] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0056] This application uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that for those skilled in the art, various modifications, combinations, sub-combinations, and substitutions can be made without departing from the principles of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A two-phase immersion battery cooling system, characterized in that, include: The condenser includes a condenser pipe (11) and fins (12) disposed outside the condenser pipe (11) for heat dissipation, wherein the fins (12) are arc-shaped inclined heat dissipation fins. A spiral inner rib is set inside the condenser pipe (11). The height of the inner rib is 1 / 8-1 / 10 of the inner diameter of the pipe, and the spiral helix angle is 30°-45°. The inner rib and the arc-shaped inclined fins (12) outside the pipe form an inner and outer double disturbance structure. The coolant inside the pipe is guided by the inner rib to form a spiral flow, and the steam outside the pipe is directionally flowed through the grooves between the fins (12). Immersion chamber (2), the immersion chamber is a sealed container, the top of which is connected to the condenser, the interior is filled with coolant and contains a battery module (3) wrapped in a double mesh. The bottom sealing base (4) is sealed to the bottom of the immersion cavity (2); Grooves (13) are formed between adjacent fins (12) in the fins (12), and the spacing between the grooves gradually decreases from the top to the root of the groove. The root of the groove (13) adopts a narrow and deep multi-stage stepped shape near the condenser pipe (11). The coolant film is thicker here, and the stepped structure can effectively capture and drain the liquid in sections to reduce the thickness of the liquid film and reduce the thermal resistance. The middle part of the groove (13) transitions into a wave-shaped or sawtooth shape to disturb the airflow, destroy the air boundary layer, and provide capillary attraction for the coolant to help it gather in the middle. The top of the groove (13) near the edge of the fin (12) is designed as a wide and shallow drainage channel, pointing to the edge of the fin (12), which will throw the coolant gathered in the middle out of the fin (12) to prevent the coolant from accumulating in the edge area of ​​the fin (12) so as to achieve zoned control of coolant generation, collection and discharge. The double-layer mesh surrounding the battery module includes a fine wire mesh (31) and a coarse wire mesh (32). The fine wire mesh (31) is tightly attached to the battery module (3), and the coarse wire mesh (32) is located outside the fine wire mesh (31), increasing the contact area with the coolant and accelerating the transfer of heat to the coolant. The fine wire mesh (31) rapidly diffuses local hot spots on the battery surface to the entire mesh surface, achieving heat balance. The coarse wire mesh (32) disturbs the flowing coolant, changing it from laminar to turbulent flow. The battery module (3) is composed of at least two cylindrical batteries and has an overall rectangular block shape. During operation, the battery module (3) generates heat, which is rapidly transferred to the surrounding coolant through the double-layer mesh on the surface of the battery module (3). After absorbing the heat, the coolant undergoes a phase change to form steam. The steam rises to the condenser area and comes into contact with the pipes and fins (12) of the condenser. The double-layer mesh extends along the circumference and axis of the cylindrical battery to form a spiral mesh. At each intersection, the mesh interlocks, wraps around, or is fixedly connected to each other to form a stable mesh node. The long axis of the mesh forms an angle of 15°-20° with the axis of the battery module. Micro guide vanes are set at the intersection of the meshes. The guide vanes are inclined at 30° with the mesh plane to guide the coolant to form a spiral upward flow.

2. The two-phase immersion battery cooling system as described in claim 1, characterized in that, A pressure measuring hole is provided on the immersion chamber (2) at a position corresponding to the condenser inlet, and the pressure change inside the immersion chamber (2) is monitored in real time by a pressure gauge (21).

3. The two-phase immersion battery cooling system as described in claim 2, characterized in that, It also includes a solenoid valve (22), which is installed at the inlet of the condenser and is matched with the pressure gauge. The solenoid valve (22) is adjusted according to the pressure in the immersion chamber to control the liquid inlet of the condenser, dynamically adjust the cooling intensity, and ensure that the temperature and pressure in the immersion chamber (2) are stable.

4. The two-phase immersion battery cooling system as described in claim 1, characterized in that, The condenser consists of at least two parallel condensing pipes (11) with fins (12) surrounding the outer wall of the condensing pipes (11).

5. The two-phase immersion battery cooling system as described in claim 4, characterized in that, It also includes a U-shaped connecting pipe (14), which is connected to both ends of the condenser pipe (11) to form a U-shaped connecting pipe (14), so as to achieve uniform distribution of cooling liquid in the condenser and extend the flow path of liquid in the condenser.

6. The two-phase immersion battery cooling system as described in claim 1, characterized in that, The cooling liquid in the condenser carries away the heat of the steam through the pipe wall and fins (12). After the steam undergoes a phase change and re-condenses into cooling liquid, it flows back into the immersion chamber (2) and participates in the heat exchange cycle again.

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