Immersion cooling battery system integrated with enclosure

Abstract

To provide an immersion cooling battery system integrated with an enclosure.SOLUTION: Proposed is an immersion cooling battery system integrated with an enclosure, which is a battery system integrated with an immersion method that complements shortcomings of a battery system using the immersion method, thereby reducing production costs, simplifying manufacturing, easing maintenance, enabling efficient thermal management, and securing high fire safety, where the battery system enables battery operation regardless of external environmental conditions and is designed to prevent surrounding environmental pollution due to leakage of an immersion fluid.SELECTED DRAWING: Figure 20

Description

[Technical field]

[0001] The present invention relates to an independent housing that integrates an immersion type thermal management system with a battery, and more specifically, to a battery system integrated with an immersion type that overcomes the drawbacks of a battery system that uses an immersion type, reduces production costs, is easy to manufacture, is easy to maintain, has efficient thermal management, and has high fire safety, and is capable of battery operation regardless of external environmental conditions and takes into consideration the prevention of contamination of the surrounding environment due to leakage of the immersion coolant fluid. [Background technology]

[0002] Electric energy is used in a variety of fields, but due to the depletion of fossil energy sources that generate electric energy, policies to reduce greenhouse gas emissions, and various environmental regulations, policies are being promoted to use unlimited renewable energy that is more environmentally friendly and does not have to be worried about depletion. However, due to the characteristics of renewable energy, it is not possible to guarantee a sustainable and stable energy supply.

[0003] Energy storage systems (ESS) have the advantage of being able to compensate for the intermittency of renewable energy. As battery technology advances, their use has grown rapidly in recent years, and this trend is expected to continue.

[0004] To meet these market needs, energy storage devices are undergoing continuous technological development to improve their energy density, efficiency, safety, and economy. Of the various types of batteries used in energy storage devices, lithium-ion batteries, which are electrochemical batteries, are the most commonly used due to their high energy density and economy. However, energy storage devices are relatively sensitive to temperature, and if they are operated for a certain period of time outside the appropriate temperature range, localized parts may overheat or the temperature difference between batteries may become large, threatening their performance and safety, so an appropriate thermal management system is required.

[0005] The battery of the energy storage device generates heat during the charging and discharging process, and if the generated heat is excessive, it may accelerate the deterioration of the battery, which may cause damage to the internal components of the battery, which may directly cause a fire. Therefore, it is very important to effectively control the heat of the battery in terms of the life and safety of the battery.

[0006] There are several methods for controlling the heat of a battery, including air-cooling, water-cooling, liquid immersion, etc. Air-cooling uses air as a cooling medium and circulates it by natural or forced convection to cool the battery. It is the simplest and most economical method and is the most commonly used battery thermal management system for applications that do not require high output. However, it has drawbacks such as dust and moisture may enter the battery due to the circulating air and low cooling performance due to the low specific heat and density of air.

[0007] The water-cooling type is an indirect cooling method in which coolant is circulated around the battery through a cooling plate. The water-cooling type mainly uses a mixture of water and ethyl glycol as a cooling medium, and has high cooling efficiency due to the high specific heat and density of the refrigerant. However, it has disadvantages such as increased complexity and cost compared to the air-cooling type due to additional manufacturing processes, high manufacturing difficulty, risk of short circuit due to leakage of conductive refrigerant, and the need for additional equipment for refrigerant heat exchange.

[0008] The immersion cooling method is a method in which the heat source is fully or partially immersed in a fluid as a coolant and cooled by direct contact between the heat source and the coolant fluid. Fluids used for immersion cooling have insulating properties and are thermally safe, such as mineral oil, synthetic oil, silicone oil, and biodegradable vegetable oil.

[0009] The immersion cooling method has been partially used for over a decade in data centers and cryptocurrency mining sites that use IT equipment that generates large amounts of heat. Recently, there have been cases where the immersion method has been applied to EV battery thermal management systems. In particular, batteries used in high-performance automobiles and special vehicles that require high output are discharged at a high C-rate to shorten charge / discharge times and achieve instantaneous high start-up, which generates a lot of heat. Therefore, it is difficult to control the heat generated by the battery even with conventional water-cooled thermal management systems, and there are attempts to use the immersion method, which directly controls the heat of the battery by filling the battery module with dielectric fluid.

[0010] The insulating fluid used as the refrigerant fluid has a large heat dissipation area through direct contact with the heat source, and has a thermal energy absorption capacity more than 1,000 times that of air, making it highly efficient at cooling, and therefore able to effectively control the battery temperature. The heated fluid can be cooled through a heat exchanger and then returned to the battery for circulation, maximizing the cooling effect.

[0011] In addition, even if thermal runaway occurs in the battery, the insulating fluid's high heat transfer ability and high flash point allow the thermal energy to be quickly diffused to the surroundings, eliminating localized hot spots. In addition, in a liquid immersion state, there is insufficient oxygen in the surroundings, limiting the combustion conditions, eliminating the possibility of combustion even if thermal runaway occurs, which has the advantage of providing excellent fire safety.

[0012] However, most battery systems using the immersion cooling method have been researched and developed mainly for EV batteries. The inside of the battery module, which is a casing that houses the battery cells, is filled with insulating fluid to cool the battery cells, or a device that cools and circulates heated fluid through an external circulation loop formed by connecting the modules with manifolds and piping for more effective cooling is added.

[0013] However, the module-by-module immersion design, which fills the module with fluid, requires high sealing of the module, which requires the manufacture of a special module case or the use of expensive connectors. In particular, a typical energy storage device increases the system capacity per unit area by stacking a plurality of modules accommodating battery cells in a cabinet, and in this case, the number of connectors increases proportionally to the number of modules, which inevitably increases the manufacturing cost. In addition, the number of connectors increases depending on the assembly quality, which increases the number of potential oil leakage points, which may cause maintenance problems.

[0014] A separate fluid reservoir may be required to contain pressure changes caused by thermal expansion and contraction of the fluid, and if thermal runaway occurs in a battery cell, the inside of the sealed battery module becomes overpressurized, requiring a pressure relief device to protect the internal equipment and the module case from structural damage. However, even with the safety device, oil leakage caused by pressure cannot be avoided.

[0015] If the battery cell body inside the module becomes partially immersed due to the leakage of fluid, it may cause a thermal shock that is directly transmitted to the surrounding battery cells, and the thermal runaway phenomenon may instantly spread to the surroundings, which is undesirable in terms of fire safety.To avoid this, the volume of the module can be increased to maintain a fully immersed state even if a certain amount of oil leaks, but this is undesirable in terms of space efficiency.

[0016] In general, in an energy storage device composed of a plurality of modules, modules filled with a refrigerant fluid are connected by piping to form a circulation loop for transferring the fluid to the outside. In this configuration, when refilling or draining the fluid during installation or maintenance, the work is very troublesome, there is a high risk of injury to workers due to oil leakage onto the floor during work, and an additional work of cleaning the installation site after work is required. Therefore, a separate means is required to prevent oil leakage during installation or maintenance work, or to prevent the work from being affected even if oil leakage occurs. In particular, a separate means for preventing oil leakage is required because ordinary insulating fluids are not naturally decomposed and may cause environmental pollution in the surrounding area.

[0017] Therefore, based on this background technology, it has become necessary to provide a battery system that employs a liquid immersion cooling method, and a housing for accommodating the battery system.

[0018] That is, the present invention can be applied to effectively control heat not only in ESS batteries but also in batteries used in various fields. Summary of the Invention [Problem to be solved by the invention]

[0019] The present invention has been devised to improve the above-mentioned problems, and includes a battery module that accommodates a plurality of battery cells and has a plurality of openings arranged to allow fluid to flow in and out freely, and a fluid in which the battery module is immersed to control the heat of the battery cells to be cooled, the fluid being characterized by dielectric properties and excellent thermodynamic properties, and a sealed immersion tank that can be filled so that the battery module is immersed in the insulating fluid. Even with such a simple configuration, a higher cooling effect can be achieved than when air is used as a coolant, thanks to the high thermal energy absorption capacity (= specific heat x density) of the fluid. This method does not require a high level of sealing of the module, does not require a complex case design, and can minimize the use of special parts, so that the battery system is easy to manufacture and assemble, is economical, and is easy to install and maintain.

[0020] In addition, a circulation loop may be formed as a fluid transfer means between the inside and outside of the immersion tank, and a heat exchanger capable of exchanging thermal energy of the fluid may be included on the external circulation loop. The internal circulation loop is characterized by providing a means for passing the fluid through the inside of each module arranged inside the tank at an equal flow rate during the process in which the fluid is drawn into the inside of the tank and returns to the outside of the tank. The objective of the present invention is to provide a battery system of an immersion cooling type integrated with a housing, which efficiently controls the temperature of the battery and reduces the temperature deviation between the battery cells to increase the reliability and efficiency of the system.

[0021] The immersion tank includes a free space for accommodating expansion and contraction of the coolant fluid, and a safety device for equalizing pressure, and the safety device can play a role in preventing external dust, dirt, and moisture from entering the immersion tank. The immersion tank has a constantly sealed structure and includes a top cover that can be opened only when necessary, and a battery management system is accommodated in a separate auxiliary space located outside the immersion tank and easily separated from the fluid, thereby enhancing the safety of the system.

[0022] In addition, when the battery is installed outdoors, a plurality of reinforcing frames can be attached to appropriate positions around the immersion tank, and an outer box can be constructed by connecting the spaces formed between the frames with panels to surround the immersion tank. The space formed between the outer box and the immersion tank can contain a heat insulating material, and a double layered enclosure can be used to store oil in an emergency so that it does not leak out to the outside even if oil leaks from the immersion tank. The purpose of the present invention is to provide an immersion cooling battery system integrated with an enclosure, which is characterized in that the connection between the frame and the outer box panel is a means that does not impair the heat insulating effect or affect the paint state of the outer box, is free from the influence of the external environment (solar heat, tornadoes, etc.), and prevents contamination of the installation site.

[0023] In addition, an explosion-proof disk or a pressure relief valve may be included at the top of the immersion tank as a safety device that operates at a certain pressure to primarily protect internal facilities from battery explosion and secondarily prevent the enclosure from scattering and spreading the risk of an accident to surrounding facilities. As described above, in the case of a double layered enclosure, in order to finally discharge the pressure discharged by the explosion-proof disk or the pressure relief valve to the outside of the enclosure, a safety device that opens in one direction depending on the discharged pressure is included at the top of the enclosure, or an opening is provided at the side of the top of the outer box to discharge pressure, thereby providing an immersion cooling type battery system integrated with the enclosure that is safe from explosion. [Means for solving the problem]

[0024] In order to achieve the above object, one embodiment of the present invention includes a battery module accommodating a plurality of battery cells, a fluid having insulating properties, and a battery housing in the form of an immersion tank that provides a space to accommodate the battery module and is filled with the fluid to completely immerse the battery module, a plurality of openings provided on the outer surface of the battery module to allow the fluid to flow in and out of the interior of the battery module and to directly contact the battery cells, and an openable and closable top cover provided in the immersion tank and positioned at the top end of the immersion tank so that the battery module can be pulled into the interior of the immersion tank.

[0025] It also includes circulation piping including an external circulation loop formed outside the immersion tank so that the fluid is drawn into the interior of the immersion tank and returned to the outside, and a circulation pump provided on the external circulation loop for circulating the fluid.

[0026] The system also includes a heat exchanger located on the path of the external circulation loop, the heat exchanger including a cooling section that cools the circulating fluid.

[0027] The heat exchanger also includes a heating portion for heating the circulating fluid.

[0028] The device also includes an intake distribution pipe, which is provided on either the upper or lower surface of the immersion tank and distributes within the tank the fluid discharged from the circulation pump and drawn into the interior of the immersion tank, and a suction pipe, which is provided on the remaining surface corresponding to the direction of movement of the drawn-in fluid and draws in the fluid within the immersion tank and returns it to the circulation pump, and the intake distribution pipe and suction pipe have a plurality of openings of different sizes arranged in a row along the longitudinal direction of the piping to uniformly distribute or draw in the flow rate.

[0029] The liquid supply system further includes a multi-hole panel provided on a lower surface of the immersion tank and having a plurality of holes for distributing and moving the fluid in the immersion tank evenly inside the immersion tank.

[0030] In addition, a flow control device is provided below the perforated panel to evenly distribute the flow rate moving from the starting end to the ending end by applying an inclination, thereby enabling more efficient fluid distribution.

[0031] The upper part of the immersion tank further includes a free space that forms an air layer of a certain depth, and an oil level gauge provided on one outer surface of the immersion tank so that the position of the oil level abutting the bottom surface of the free space can be confirmed from the outside without opening the top lid of the immersion tank.

[0032] The liquid immersion tank further includes an explosion-proof disk located on the top cover thereof and opening at a constant pressure to quickly release gas and pressure generated due to failure of the battery cell, thereby protecting the liquid immersion tank and internal electrical devices.

[0033] The present invention includes a battery module that accommodates a plurality of battery cells, an immersion tank that provides a space to accommodate a fluid having insulating properties and the battery module and is filled with the fluid to completely immerse the battery module, a plurality of openings on the outer surface of the battery module so that the fluid can flow in and out of the interior of the battery module and directly contact the battery cells, an openable and closable top cover that is provided on the immersion tank and positioned at the upper end of the immersion tank so that the battery module can be pulled into the interior of the immersion tank, a plurality of reinforcing frames that are attached to appropriate positions around the immersion tank and structurally reinforce the immersion tank, and panels that connect the spaces between the reinforcing frames, the panels including an outer box that is a housing that surrounds the immersion tank.

[0034] The system also includes an accessory box located on one side of the outer box and mounted on a panel, the accessory box housing a battery management system or other electrical protection device, an oil level gauge for measuring the oil level of the fluid in the immersion tank, an accessory box access portion provided on the upper part of the outer box panel to which the accessory box is mounted and on one side of the accessory box corresponding to the upper part, the accessory box access portion being formed to match the free space filled with an air layer at the upper part inside the immersion tank, and allowing power cables and communication cables coming out of the immersion tank to access the inside of the accessory box, and a heat exchanger located on one side of the outer box, the heat exchanger being located on an external circulation loop line formed outside the immersion tank so that the fluid is drawn into the inside of the immersion tank and returned to the outside, and exchanging thermal energy of the circulating fluid.

[0035] The accessory box also includes a plurality of lower openings provided on the bottom surface of the accessory box, through which cool outside air is drawn in to remove heat generated by electrical devices in the accessory box, a plurality of upper side openings of a louver type formed on the upper end of the side of the accessory box so as to send warm air to the outside after exchanging thermal energy, a mash net provided on the inner surface of each opening to prevent insects or foreign objects from entering through the opening, and a rainwater inflow prevention partition provided diagonally along the inner surface of the opening to block rainwater flowing into the inside through the louver type upper side opening.

[0036] The system also includes a drain pipe formed on the bottom surface of the immersion tank for draining the fluid contained in the immersion tank to the outside, and the drain pipe exits the outer box through an opening provided in the bottom panel of the outer box at a position corresponding to the bottom surface of the immersion tank where the pipe is formed, and a tank fitting that connects the drain pipe to the opening in the bottom panel of the outer box, and the end of the drain pipe is finished with an open / close lock valve.

[0037] The tank further includes a fill port that is provided on an openable top lid at the top end of the immersion tank and that can fill the tank with a fluid.

[0038] The outer box also includes a removable roof that is provided on the upper end of the outer box and allows access to the inside of the outer box.

[0039] The invention also includes an explosion-proof disk that is provided on an openable top cover at the top of the immersion tank and opens at a certain pressure to quickly release gas and pressure that may be released due to a failure of a battery cell located in the immersion tank, thereby protecting the immersion tank and internal devices.

[0040] In addition, a plurality of openings are provided along the side surface of the outer box roof for discharging the pressure and gas discharged from the explosion-proof disk to the outside, a mesh net provided on the inner surface of the opening so as to prevent external insects or foreign objects from entering through the opening, a rainwater inflow prevention partition obliquely provided along the inner surface of the opening for preventing rainwater flowing in through the opening from entering inside, and a drain hole for discharging the raindrops collected while being blocked by the partition to the outside of the outer box are included.

[0041] In addition, a hinge for connecting one side surface of the outer box roof and the outer box side panel, fixed plates provided on both side surfaces of the outer box, bolts fixed to the outer box roof surface at a position corresponding to the fixed plates, a groove formed along a path H along which the bolts move while the outer box roof is opened about the hinge, and a nut coupled to the bolts to press the fixed plates and sliding along the groove of the fixed plates while the outer box roof is opened are included. At this time, a force N is applied to the nut that presses the fixed plates so that the outer box roof is opened by the pressure discharged from the explosion-proof disk.

[0042] In addition, the outer box is of a double housing type in which a gasket sandwiched between the contact surfaces between the reinforcing frame and the panel, and a screw, self-tapping screw or nail gun as a coupling member for coupling the panel, the reinforcing frame and the gasket to each other are fastened and coupled so that the abutting surfaces are pressed against each other.

[0043] In addition, a heat insulating material is included which is accommodated in the free space formed between the immersion tank and the outer box panel to block the intrusion of external heat.

[0044] In addition, the immersion tank further includes a pressure equalizing device installed on the side wall of the immersion tank formed in accordance with the free space filled with an air layer in the upper layer portion of the immersion tank so as to equalize the pressure difference caused by the thermal expansion and contraction of the fluid. The pressure equalizing device includes a dehumidifying agent for removing the moisture of the air flowing in from the outside during the process of equalizing the pressure.

Advantages of the Invention

[0045] According to one embodiment of the present invention, a battery module containing a plurality of battery cells is used, and the battery module is completely immersed in an insulating fluid as a refrigerant to control heat by directly contacting the battery cells in the module with the fluid, and the battery module is configured with an immersion tank that contains a plurality of the battery modules and has a space filled with the insulating fluid. The insulating fluid has a thermal energy absorption capacity that is more than 1,000 times higher than air, so that the insulating fluid provides excellent thermal management effects for the battery even in a simple immersion state.

[0046] By receiving fluid into the intake port of the immersion tank and increasing or decreasing thermal energy, an external circulation loop is formed in which the fluid is circulated back to the immersion tank, providing the effect of not only more efficient thermal control of the batteries but also more actively reducing temperature deviations between batteries.

[0047] Compared to the module level immersion method in which the module is filled with an insulating fluid as a refrigerant, the tank level immersion method in which the inside of the tank is filled with the fluid as described above does not require a high level of airtightness in the module, does not require a piping connection configuration between modules for fluid movement and special connectors, and provides the advantages of being simple to manufacture, low cost, and significantly reducing potential oil leakage points.

[0048] In addition, the immersion method provides an advantage that the distance that the fluid moves inside the module is shorter than that of the module-by-module immersion method, and the fluid moves uniformly in the flow direction inside the battery module, thereby improving the thermal management effect.

[0049] By configuring the battery module, insulating fluid, immersion tank and heat exchanger as a single integrated housing, the distance that fluid travels outside the immersion tank can be reduced, saving installation space and providing efficient maintenance.

[0050] In addition, the heat exchanger is composed of a cooling section, a heating section and a circulation pump, and quickly and accurately adjusts the temperature of the fluid, thereby optimizing the performance of the battery.

[0051] In addition, an auxiliary space is provided outside the immersion tank to house power and communication cables, protective equipment, and the BMS, ensuring stable management and protection, providing a key element in enhancing safety and efficiency in a complex battery system.

[0052] In addition, piping for the inflow and outflow of fluid is installed on the upper and lower sides of the inside of the immersion tank to facilitate fluid circulation and maximize heat exchange efficiency. In particular, a series of openings of different sizes formed in the piping realizes uniform flow distribution, improving the thermal management performance of the entire system.

[0053] Alternatively, a perforated panel can be installed in place of the corresponding piping on the underside of the immersion tank. A series of openings can be provided in the perforated panel, which has the effect of transmitting the flow rate in an evenly distributed manner through the perforated panel. This allows a uniform flow rate to pass through each module, and allows for stable management of temperature deviations between modules.

[0054] In addition, by installing more flow control devices, a more efficient flow distribution effect can be achieved. In an embodiment of the flow control device, an inclined panel is installed under the perforated panel to manage the fluid to move evenly to the upper side, thereby maximizing the thermal management performance of the entire system. This configuration has the effect of efficiently distributing the fluid without installing piping.

[0055] In addition, a pressure equalizer is installed in the immersion tank to accommodate the pressure generated by the expansion and contraction of the fluid, and a path for air movement is placed in the pressure equalizer. A desiccant is installed on this path, which removes moisture from the external air drawn into the tank, thereby protecting the insulation performance of the internal electrical equipment.

[0056] In addition, a free space that forms an air layer is provided at the top of the immersion tank to prevent overpressure from forming in the tank due to expansion and contraction of the fluid, thereby improving safety. At this time, the oil level abutting the free space maintains a certain distance to the battery cell located at the top of the tank, so that even if there is a loss of fluid, the battery maintains a fully immersed state, thereby improving safety.

[0057] By installing an oil level gauge in the immersion tank, the fluid level and the oil leakage state can be checked from the outside without directly looking inside the immersion tank, enabling efficient maintenance.

[0058] In addition, the immersion tank can be structurally reinforced by surrounding it with multiple reinforcing frames, and the spaces between the frames can be connected with panels to form a double-casing type outer box surrounding the immersion tank. This configuration improves the stability and thermal efficiency of the entire structure and facilitates environmental management by preventing oil leakage in an emergency.

[0059] In addition, the outer box panel and the reinforcing frame can be joined by welding or gasket sealing, but welding can have problems such as difficulty in maintaining the quality of the paint and the resulting risk of rust, warping of the panel due to thermal deformation, variation in welding quality depending on the skill of the worker, and heat penetration from the outside to the inside along the welded surface. Therefore, the gasket sealing method is more preferable and can improve the manufacturing quality and insulation performance of the structure.

[0060] Additionally, additional insulation will be installed in the space between the immersion tank and the outer box panels to minimize heat loss and improve energy efficiency.

[0061] In addition, to prevent fluid leaking from the immersion tank from leaking to the outside, the piping that penetrates the outer box panel uses tank fittings, etc. to facilitate manufacturing and assembly, and a fuel fill port is provided on the top lid of the immersion tank to enable refueling without opening the inside during installation or maintenance, thereby preventing contamination of the fluid.

[0062] In addition, an explosion-proof disk or pressure relief valve that opens at a certain pressure is installed at the top of the immersion tank, thus protecting the entire structure from battery explosion pressure. Also, a roof is installed on the outer box facing the top lid of the immersion tank, and an opening is formed on the side of the roof, or a hinge and fixing device are combined to open the box around one side of the roof, thereby enhancing safety by releasing the internal pressure to the outside in an emergency. [Brief description of the drawings]

[0063] [Figure 1] FIG. 1A is an example of applying the immersion method to a conventional rack-type battery system, and FIG. 1B is a diagram showing the concept of integrating a battery system integrated with the immersion method according to one embodiment of the present invention with a tank-type housing. [Diagram 2] FIG. 2 is a schematic diagram illustrating the configuration of an immersion type battery system integrated with a housing according to one embodiment of the present invention. [Diagram 3] (a), (b), (c), and (d) show experimental data showing the cooling efficiency of an air-cooled battery system and a liquid-immersed battery system, and (e) and (f) show experimental data evaluating the fire safety of the liquid-immersed battery system. [Figure 4] FIG. 1 shows a schematic diagram of one embodiment of the present invention for achieving a safety distance d to increase fire safety. [Diagram 5] 4 is a diagram illustrating a schematic configuration of an outlet of a battery module according to an embodiment of the present invention; FIG. [Figure 6]2 is a schematic diagram illustrating a fluid intake distribution pipe and a suction pipe arranged inside an immersion tank according to an embodiment of the present invention, and the flow direction according to the fluid intake distribution pipe and a suction pipe arranged inside the immersion tank according to an embodiment of the present invention; [Figure 7] 1 is a diagram showing the configuration of a multi-hole panel and a flow control device inside an immersion tank according to an embodiment of the present invention, and a schematic diagram showing the flow direction according to the configuration; [Figure 8] FIG. 13 is a diagram showing a computer analysis model and analysis results showing flow distribution according to an embodiment of the present invention. [Figure 9] FIG. 2 illustrates a schematic diagram of an immersion tank and a frame that surrounds and structurally reinforces the immersion tank, in accordance with one embodiment of the present invention; [Figure 10] 1 is a schematic diagram showing a dual-enclosure type outer box constructed using an outer box panel, a frame, a gasket, and a connecting member according to an embodiment of the present invention; [Figure 11] 1A and 1B show cross-sections of a gasket sandwiched between an outer box panel and a frame in accordance with one embodiment of the present invention, and FIG. 1C is a schematic diagram showing a configuration including insulation in the space between the outer box panel and the immersion tank. [Figure 12] 2 is a schematic cross-sectional view of a support leg and a base frame for vertically and horizontally supporting an outer box according to an embodiment of the present invention; FIG. [Figure 13] FIG. 2A shows the configuration of a fluid drainage device for maintenance according to one embodiment of the present invention, and FIG. 2B is a diagram showing the schematic configurations of a fuel supply device and an explosion-proof device according to one embodiment of the present invention. [Figure 14] 1 is a diagram showing an outline of the roof configuration of an outer box according to one embodiment of the present invention and an opening formed on a side surface of the roof, and also showing a shape and structure for preventing the inflow of rainwater. FIG. [Figure 15] FIG. 2 is a schematic diagram illustrating the configuration of an explosion-proof outer box roof structure according to one embodiment of the present invention. [Figure 16] 1A-1C are schematic diagrams illustrating various devices configured to open the outer box roof at a certain pressure for explosion prevention according to an embodiment of the present invention. [Figure 17]FIG. 17 is a diagram showing the mechanism by which the roof is opened by the device described in FIG. 16 and the relationship between the forces required to achieve this. [Figure 18] 1 is a schematic diagram illustrating a configuration of a separate space for ancillary facilities located at a front part of an outer box according to an embodiment of the present invention; [Figure 19] 2 is a schematic diagram illustrating an outer box housing including an accessory box and a heat exchanger according to an embodiment of the present invention, and a configuration of the accessory box for dissipating heat and preventing the intrusion of external substances; [Figure 20] 11 is a configuration according to another embodiment of the present invention. [Figure 21] FIG. 11 is a detailed cross-sectional view according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] The above-mentioned present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0065] It should be noted that the technical terms used in the present invention are merely used to describe a particular embodiment and are not intended to limit the present invention. In addition, unless otherwise defined in the present invention, the technical terms used in the present invention should be interpreted in a generally understood sense by a person having ordinary knowledge in the technical field to which the present invention belongs, and should not be interpreted in an overly comprehensive sense or an overly narrow sense. Furthermore, if the technical terms used in the present invention are incorrect technical terms that do not accurately express the idea of ​​the present invention, they should be replaced with technical terms that can be correctly understood by a person skilled in the art. In addition, the general terms used in the present invention should be interpreted according to the definition in a dictionary or according to the context, and should not be interpreted in an overly narrow sense.

[0066] In addition, singular expressions used in the present invention include plural expressions unless the context clearly indicates otherwise. In the present invention, the terms "comprise" or "include" should not be interpreted as including all of the various components or steps described in the present specification, but may include some of the components or steps, or may further include additional components or steps.

[0067] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Identical or similar components will be designated by the same reference numbers regardless of the reference numbers, and duplicate descriptions thereof will be omitted.

[0068] In addition, when describing the present invention, if it is determined that a detailed description of related known technology may make the gist of the present invention unclear, the detailed description will be omitted. In addition, it should be noted that the attached drawings are merely for the purpose of making the concept of the present invention easier to understand, and the concept of the present invention should not be construed as being limited by the attached drawings.

[0069] FIG. 1 is a schematic diagram showing (a) a rack system and (b) a tank system for implementing a battery system using a liquid immersion cooling method.

[0070] As shown in FIG. 1(a), a common battery system structure follows a rack format in which modules housing battery cells and battery modules are stacked vertically. This format has the advantage of increasing the energy density per unit area, but to realize the immersion cooling method, the module must be filled with a fluid as a coolant. To prevent oil leakage, the fluid-filled module must use a casing design and special connectors for high sealing, and piping connections between modules are required for fluid movement. This has the disadvantages of increasing the number of potential oil leakage points, complicating maintenance issues, and increasing the overall vertical weight due to the weight of the modules. In addition, passing piping between modules for fluid circulation increases the travel distance of the fluid moving outside, which is not efficient in terms of thermal management.

[0071] In order to make up for these shortcomings, the present invention is a tank type in which a tank 100 housing a battery module 2 is filled with a cooling fluid 3 to completely lock the module, as shown in Fig. 1(b), and therefore high sealing is not required in the module, and the number of parts required is minimized, making it easy to manufacture and assemble. The number of potential oil leakage points is minimized, making maintenance easy, a separate fluid storage device for pressure regulation and circulation within the tank is not required, and the distance that fluid travels outside the immersion tank 100 is short, making it more efficient in terms of heat management.

[0072] Therefore, the present invention comprises an immersion tank 100 designed to effectively impregnate a battery module 2 with a fluid 3 as a cooling medium, thereby maximizing the cooling efficiency of the battery and minimizing oil leakage points to improve the safety and reliability of the entire battery system.

[0073] The above-described structure has a fluid storage function for dealing with oil leakage in an emergency, by including an outer box 200 designed in the form of a double housing surrounding the immersion tank 100 to provide protection against oil leakage to the outside in the event of a possible oil leakage from the immersion tank 100.

[0074] As shown in Fig. 2, the present invention shows an embodiment of an immersion cooling type battery system integrated with a housing that integrates the immersion tank, a space for accommodating a BMS (Battery Management System) and other electrical protection devices, and a heat exchanger into one space, and a schematic spatial configuration diagram. The battery system includes an accessory box 1-1 that is located on one side of an outer box and provides a space for accommodating a BMS or other electrical protection devices to be installed. The heat exchanger 9 is located on an external circulation loop to adjust the thermal energy of the fluid sucked from the immersion tank 100 and then return it to the immersion tank. In order to minimize the flow distance of the fluid outside, the heat exchanger is configured on one side of the outer box, and a housing is provided to accommodate the battery system integrated with the heat exchanger.

[0075] The heat exchanger 9 includes a cooling unit and a circulation pump, and a heating unit may be added as necessary. The cooling unit (not shown) cools the fluid, and the cooled fluid removes heat from the battery. The circulation pump 7 forcibly circulates the fluid to increase the cooling efficiency. The heating unit (not shown) heats the fluid to help the battery maintain optimal performance even in a low-temperature environment.

[0076] The heat exchanger 9 is integrated with the battery system and housed in a single space, which reduces the complexity of the system, improves the system efficiency, and provides ease of maintenance. As such, the heat exchanger 9 optimizes the performance of the battery system, ensures stable operation under various operating conditions, and improves the overall energy management efficiency.

[0077] The graph in Figure 3 shows the results of an in-house experiment to verify the efficiency and fire safety of the immersion cooling method.

[0078] The upper graphs (a), (b), (c), and (d) in Figure 3 show the time history data of the self-experimental results to investigate the effect of battery thermal control by immersion cooling and internal fluid circulation. A total of 10 battery modules were arranged in a tank, and the tank was filled with insulating fluid, after which the battery was charged and discharged under three conditions.

[0079] The first condition was a simple liquid immersion state with no fluid circulating, the second condition was a forced circulation of the fluid using a circulation pump, and the third condition was a charging / discharging operation in which the circulating fluid was cooled via a heat exchanger.

[0080] For comparison, seven battery modules were stacked on a separate battery rack and then charged and discharged at the same C-rate using natural convection cooling.

[0081] In all experiments, the temperature of the battery cells was measured at two different points per module and observed for about nine hours after charging and discharging was completed.

[0082] As shown in Figure 3(a), in the case of natural convection, the maximum battery temperature exceeded 40°C, whereas in the case of simple immersion, the maximum battery temperature was recorded in the low 30s°C, as shown in Figure 3(b). In the case of circulating fluid, as shown in Figure 3(c), the maximum battery temperature was not significantly different on average from the simple immersion state, but the temperature deviation between the battery cells was much reduced. Finally, in the case of simultaneous circulation and cooling via a heat exchanger, as shown in Figure 3(d), the maximum battery temperature did not exceed 27°C, and the temperature deviation between the battery cells was also much reduced compared to the cases of Figure 3(a) and (b).

[0083] Therefore, it was confirmed that a significant cooling effect can be obtained even with simple liquid immersion, that temperature deviation between batteries can be dramatically reduced by fluid circulation, and that when cooling fluid, it is possible to effectively control the maximum temperature of the battery even during high C-rate operation.

[0084] The graph and photo at the bottom of Figure 3 show the test specimen for the fire safety evaluation experiment and the results.

[0085] In the fire safety evaluation test, a specific battery cell was heated from an external power source to cause thermal runaway and check whether it would spread to surrounding cells. When thermal runaway occurs, the temperature of the battery cell rises rapidly, recording a peak temperature of over 600 degrees. Therefore, by observing the temperature of the body of the surrounding cells, it is possible to determine whether thermal runaway propagation has occurred.

[0086] As shown in Figure 3 (e), in the first experiment, multiple battery cells were arranged vertically inside the test chamber and the test chamber was completely filled with fluid. Two pre-specified adjacent battery cells were then heated simultaneously. As a result, after the first thermal runaway occurred (over 600°C), when the second thermal runaway occurred, the temperature of the body of the surrounding cell also instantly recorded a high temperature of over 800°C, indicating that the thermal runaway phenomenon had transferred to the surrounding cells. When the first thermal runaway occurred, some of the fluid escaped from the chamber along with the pressure, at which point some of the body of the remaining battery cell was exposed outside the fluid. It was determined that when the thermal runaway occurred in the second cell, the surrounding cells were exposed to the high temperature, triggering the thermal runaway transition.

[0087] As shown in Figure 3(f), in the second test, the battery cells were arranged horizontally, and the inside of the chamber was completely filled with fluid, with a certain distance between the topmost battery cell and the top cover of the test chamber to ensure that the battery cells remained fully immersed during the experiment. Two pre-specified adjacent battery cells were heated simultaneously, and even while a thermal runaway occurred in the specified cell, the temperature of the surrounding battery cell bodies remained below 100 degrees, and no thermal runaway transition occurred. It was found that even if some of the fluid escaped during thermal runaway, the remaining battery cells remained fully immersed and were protected from thermal shock, so no transition occurred.

[0088] The results of this experiment show that an important factor to consider in reducing the risk of fire is to ensure a certain distance between the fluid level and the topmost battery cell in order to maintain full immersion despite fluid loss.

[0089] Based on the fire safety evaluation experiment results of FIG. 3, as shown in FIG. 4, the present invention shows key components for enhancing fire safety by ensuring a safety distance d between the oil level of the fluid 3 and the battery cell located at the top. As shown in (a) and (b) of FIG. 4, the safety distance d can be realized in the rack type and the tank type. However, as shown in (a) of FIG. 3, in the case of the rack type, it is difficult to ensure a certain distance d due to spatial constraints, and the only way to solve this is to increase the volume of the module, which is disadvantageous in terms of space efficiency. In contrast, in the tank type, there is more spatial freedom in ensuring a certain length of safety distance d.

[0090] In addition, in the tank system, a free space having an air layer of a certain depth D can be secured at the top of the tank 100. Such a free space is very effective in preventing overpressure in the tank due to volumetric expansion and contraction of the fluid 3.

[0091] In the present invention, in order to more effectively control the heat of the battery, the design of the battery module 2 maintains a uniform flow of fluid 3 so that the battery cells inside the module can be cooled with the same flow rate.

[0092] As shown in FIG. 5, in order to effectively remove heat from the battery module 2 according to the present invention, the heat is drawn evenly into the interior of the module and discharged to the exterior according to the flow direction.

[0093] In an embodiment of the present invention, a plurality of first outlets 2 to 6 are formed at either one of both ends of the battery module. The first outlets are inlets through which fluid is drawn in, and serve to supply the fluid to the inside of the battery module 2 and directly contact the battery cells to absorb and transfer heat. The first outlets 2 to 6 are important parts for supplying fluid to the battery module for efficient cooling of the battery module.

[0094] The fluid 3 drawn into the battery module through the first outlets 2-6 moves from the lower part to the upper part of the module and is discharged to the outside of the module through the plurality of second outlets 2-7. The second outlets 2-7 are formed in accordance with the moving direction of the fluid drawn in from the first outlets 2-6, and serve as an outlet for the fluid that has absorbed heat after passing through the battery module 2, and third outlets 2-8 may be further formed on the upper side surface.

[0095] Therefore, such an arrangement of the outlets allows the fluid to pass evenly through the inside of the battery module while minimizing the main flow distance, effectively absorbing internal heat and transferring it to the outside of the battery module, thereby more uniformly and effectively maintaining the temperature of the battery cells in the battery module.

[0096] In the present invention, in order to evenly control the heat of each battery module 2 contained in the immersion tank 100, a uniform flow rate is maintained in the flow direction inside the immersion tank 100 so that the cooling effect can be applied equally to each module.

[0097] 6, an inlet distribution pipe 11 is provided on the bottom of the immersion tank 100, which moves fluid from the outside through an inlet port and distributes it to the inside, and an intake pipe 12 is provided on the top of the immersion tank 100, which returns the fluid to the outside, and a certain number of holes 13 of different sizes are formed in series in the longitudinal direction in the inlet distribution pipe 11 and the intake pipe 12. This configuration allows the fluid 3 drawn into the immersion tank 100 to be distributed at an even flow rate to the upper part of the tank as it moves inward, thereby providing an even cooling effect to each module.

[0098] 7 shows an embodiment of the present invention for more efficient flow distribution. A multi-hole panel 15 is provided on the bottom surface of the immersion tank 100 instead of the inlet distribution pipe 11 and includes a plurality of holes 13 located under the module to uniformly transfer the fluid to the upper part, and a flow control device 16 formed of a panel having a slope inclined from the starting end to the end is further provided under the multi-hole panel.

[0099] Specifically, the interior of the immersion tank of the present invention functions to distribute the fluid drawn in from the outside to the upper side at an even flow rate while it moves inward, providing the same cooling effect between each module and reducing the temperature deviation of the battery, thereby expecting high reliability, safety, and extended life of the battery system.

[0100] Figures (a) and (c) of Fig. 8 are 3D fluid dynamic models for examining whether the fluid drawn into the lower part of the immersion tank 100 and equipped with the draw-in distribution pipe 11 is evenly distributed to the upper part while moving inward, and the fluid mass flow distribution results calculated at a height of 60 mm from the lower part of the tank. Figures (b) and (d) of Fig. 8 are 3D fluid dynamic models for examining whether the fluid is evenly distributed to the upper part while moving inside the tank, with the porous panel 15 provided at the lower part of the immersion tank and the inclined flow control device 16 provided on the lower surface of the porous panel, and the graph of the fluid mass flow distribution results calculated at a height of 60 mm from the bottom surface of the tank.

[0101] As shown in the fluid flow distribution result graphs of Figs. 8(a) and 8(b), it is shown that the flow distribution is more uniform in the model composed of the porous panel 15 and the flow control device 16 than in the model composed of the draw-in distribution pipe 11, indicating that the fluid can be efficiently distributed through the porous panel and the flow control device. Such a configuration has the advantage that the welding work for pipe connection is not required, the manufacturing becomes simple, and efficient fluid distribution can be achieved.

[0102] As shown in Fig. 9, according to an embodiment of the present invention, a number of horizontal frames 110, 140 for horizontal and vertical reinforcement and vertical frames 120 are included around the immersion tank 100.

[0103] Such a configuration improves the structural stability of the immersion tank 100, and the horizontal frames 110, 140 and the vertical frames 120 become elements constituting the outer box in the double housing form to protect the immersion tank 100 from the surrounding environment.

[0104] The frames 110, 120, and 140 serve to support the immersion tank 100 and, when combined with the panels that make up the outer box, form a double housing structure that confines any fluid that leaks from the immersion tank in an emergency so that it does not escape to the outside, thereby preventing environmental pollution due to the fluid leaking out.

[0105] 10, a gasket 251 is attached between the panel 210, 211 and the frame 110, 120, 140. The gasket 251 is firmly connected to each other by a connecting member 252. The connecting member can include a screw, a self-tapping screw, or a nail gun, which presses the gasket between the panel and the frame to provide a sealing effect, and completes the double housing form composed of the immersion tank and the outer panel.

[0106] This double-casing type can protect the immersion tank from impacts caused by tornadoes, prevent oil leakage through gasket seals, and block the thermal conduction path through which external heat enters the interior, improving the reliability and safety of the immersion-cooled battery system and improving the efficiency of thermal management.

[0107] As shown in (a) and (b) of FIG. 11, in an embodiment of the present invention, a cross section of a gasket 251 sandwiched between an outer box panel and a frame, and a connecting member 252 connecting the gasket 251 and a connecting member 252 are shown.

[0108] 11(c), the empty space formed between the exterior and bottom of the immersion tank 100 and the panels 210, 211 of the outer box contains insulation 142. The insulation plays an important role in protecting the immersion tank from external heat and maintaining the thermal management efficiency and performance consistency of the immersion system.

[0109] The thermal insulation material 142 is disposed so as to surround the entire outer surface of the immersion tank 100, and minimizes the influence of heat from the outside. This configuration minimizes the influence of the external environment and keeps the temperature of the immersion tank stable.

[0110] Therefore, the immersion-cooled battery system integrated with the housing of the present invention improves the reliability and safety of the battery by addressing various heat-related issues that may arise during battery use.

[0111] 12, in order to effectively support the double-casing type outer box 200 of the present invention, the coupling device of the support stand that supports the outer box includes a base frame 303 installed at the bottom and support legs 305. The base frame plays a role in transferring the weight of the entire system to the support legs, and the support legs transfer the vertical and horizontal loads transferred to the base frame to the floor.

[0112] As shown in (a) of FIG. 13, in one embodiment of the present invention, a drain pipe 222 is installed penetrating the bottom surface 150 of the immersion tank and the bottom panel 210 of the outer box to easily drain the internal fluid to the outside for maintenance purposes, and the drain pipe and the bottom panel of the outer box are finished to prevent oil leakage using a tank fitting 221.

[0113] The drain pipe is terminated with an open / close lock valve 223 (not shown) so that it can be opened and closed as necessary during maintenance and replacement of the fluid 3.

[0114] 13(b), a device for supplying fluid 3 without opening the top lid 1-2 of the liquid immersion tank is included. A fuel supply port 19, which is a fuel supply device, is included and is installed at a fixed position on the top lid.

[0115] The oil supply port 19 formed in the top cover 1-2 prevents the fluid from leaking out along the side of the outer box even if the fluid is flowing during refueling. In addition, by supplying fuel through the oil supply port, it is not necessary to open the inside of the immersion tank, which prevents the fluid from being contaminated by contact with the surrounding environment during refueling as much as possible.

[0116] Also, as shown in Fig. 13(b), the immersion tank 100 of the present invention includes an explosion-proof disk 1-21 or a pressure discharge valve, which is a device for sensing a rapid increase in internal pressure due to a battery failure and ensuring safety. The explosion-proof disk 1-21 is arranged on the upper lid 1-2 of the immersion tank and is opened when the internal pressure reaches the opening pressure to quickly discharge the pressure inside the immersion tank to the outside. The opening pressure is preferably 0.2 to 0.4 bar, and it plays a role in preventing the accumulation of internal pressure at the opening pressure and protecting the internal structure of the tank.

[0117] Such a configuration of the present invention reflects a design that simultaneously considers safety, efficiency, ease of manufacturing, and ease of maintenance, and improves the functionality and reliability of the immersion cooling type battery system integrated with the housing.

[0118] As shown in Fig. 14(a), the outer box 200 of the double housing type includes a detachable roof 201, and a roof opening 1-22 is formed on the side surface of the roof so as to prevent heat storage due to solar heat in the space between the immersion tank 100 and the roof. As shown in Fig. 14(b), in order to prevent external fluids such as rainwater from flowing into the interior through the roof opening, an inclined rainwater inflow prevention partition 1-24 is installed in a section corresponding to the roof opening along the inner surface of the roof, and a drain hole 203 is provided below it.

[0119] The rainwater inflow prevention partition 1-24 effectively blocks rainwater from entering the interior of the outer box. One or more drain holes 203 are provided so that the rainwater collected by the partition is discharged to the outside. These drain holes prevent rainwater from accumulating on the bottom surface of the outer box roof and effectively prevent the inflow of fluid into the outer box interior.

[0120] The outer box roof structure of the present invention can minimize the adverse effects caused by changes in the external environment by preventing the inflow of rainwater and using natural convection to prevent heat from accumulating inside.

[0121] 15(a), the roof opening 1-22 serves to quickly guide to the outside the gas and pressure discharged when the explosion-proof disk 1-21 installed on the top cover of the immersion tank 100 is opened. In this case, the total area of ​​the roof opening must be sufficiently larger than the opening area of ​​the explosion-proof disk so that the gas and pressure can be quickly discharged to the outside.

[0122] 15(b), in the immersion cooling type battery system integrated with the housing, a volume damper 225 is installed on the side of the outer box roof. The damper 225 plays a role in quickly directing the gas and pressure discharged when the explosion-proof disk is opened to the outside.

[0123] The damper 225 opens the damper blade 225-1 by the opening pressure of the explosion-proof disk 1-21, and quickly releases the pressure to the outside. Such pressure release is essential to safely protect the battery from explosion. Such a structure functions as an important safety design element in the outer box structure of the present invention which is configured in a double housing format.

[0124] As shown in Figs. 16 and 17, as another example of the present invention, a mechanism for automatically opening the exterior roof 201 and the side panel 211 of the outer box by explosion pressure using the connection structure will be described in detail.

[0125] The outer box roof 201 was designed such that in the event that a situation occurs where an explosion-proof disk located on the immersion tank 100 is opened due to an increase in internal pressure, said roof will open to vent pressure.

[0126] For this purpose, the rear surface of the outer box roof 201 can be connected to the outer box side panel 211 that abuts against it by a hinge 218. This device allows the outer box roof to be opened around the hinge. At this time, the lower part of the fixing plate 212 formed at the place where the side surface of the outer box roof 201 and the outer box side panel 211 meet is fixed to the outer box side panel, and a bolt 1-27 is fixed to the roof side surface corresponding to the upper part of the fixing plate.

[0127] The fixing plate is crimped by connecting the nut 1-28 to the bolt 1-27, and at this time, the roof of the outer box is opened on the upper part of the fixing plate, and a guide groove is formed along the path H along which the bolt moves. The guide groove serves to accommodate the bolt 1-27 fixed to the roof of the outer box. The bolt is fastened to the nut 1-28, and in this process, the roof is fixed under normal conditions by the crimping force formed on the surface where the fixing plate and the nut contact. In an emergency, the crimping force applied to the nut can be determined so that the nut slides on the contact surface with the fixing plate so that the roof can be opened around the hinge as an axis.

[0128] As shown in Figure 17, a conditional formula can be created to obtain the maximum frictional force so that the moment caused by the force pushing out the roof is greater than the moment caused by the roof's self weight and frictional force. The frictional force can be obtained from the pressure applied to the nut 1-28 and the metal surface friction coefficient, and by substituting this relational formula into the above conditional formula, the maximum pressure applied to the nut can be obtained as shown in the following formula 1.

[0129]

number

[0130] As shown in Figures 18 and 19, the main components of the battery system are integrated with the housing and have a liquid-cooling system.

[0131] Heat that may be generated during operation of the battery may cause the fluid 3 to expand or contract, which may create a pressure difference between the inside and outside of the tank. To manage such pressure differences, the immersion tank is further equipped with a pressure equalization device 161.

[0132] The pressure equalization device senses the pressure difference between the inside and outside of the tank when the pressure inside the tank increases, and adjusts the inflow and outflow of air to prevent overpressure in the immersion tank due to thermal expansion and contraction of the fluid 3, to protect the electrical equipment in the immersion tank, and to maintain the structural stability of the immersion tank.

[0133] In addition, the pressure equalizing device 161 includes a desiccant for removing moisture on the path of the air movement passage, thereby removing moisture from the air drawn in from the outside and protecting the internal electrical devices and the fluid 3 from moisture.

[0134] In addition, an accessory box 1-1, which is a space for accommodating power and communication cables, protective equipment and a BMS, is placed outside the immersion tank and connected to the outer box side panel 211 to be isolated from the fluid, thereby enabling stable management.

[0135] The accessory box is attached to an outer box side panel 211, and includes an accessory box access section 290 having an opening formed on the panel to which the accessory box is attached and on the rear surface of the accessory box corresponding to the panel. The access section 290 is located to correspond to a free space D formed in the upper part of the immersion tank, and allows the power cable and communication cable coming out of the immersion tank to approach the accessory box without being contaminated.

[0136] In order to monitor the oil level condition in the immersion tank, an oil level gauge 162 is provided on one surface of the immersion tank corresponding to the opening.

[0137] A plurality of openings 174 are provided on the bottom surface of the accessory box 1-1, so that cool outside air can be drawn in to remove heat from the electric devices inside the accessory box. A plurality of louver-type openings 172 are formed on the upper end of the side surface of the accessory box, so that the warm air can be discharged to the outside after the exchange of thermal energy. Mash nets 171 are provided on the inner surface of each opening to prevent insects or foreign objects from entering from the outside. In order to block rainwater flowing in through the louver-type upper side openings, a rainwater inflow prevention partition 173 is provided inside the accessory box and obliquely installed to face the side openings.

[0138] In addition, the heat exchanger 9, which exchanges thermal energy of the circulating fluid by connecting it to circulation pipes 11, 12 that form an external circulation loop that is drawn into the inside of the immersion tank and returned to the outside, is located on the outer box side panel 211 and is integrated with the housing.

[0139] Below, examples of immersion battery systems integrated with housings that are specifically implemented in accordance with various configurations of the present invention are provided.

[0140] Embodiment As shown in (a) of FIG. 20, the present invention includes a battery housing in the form of an immersion tank 100 that houses a battery module 2 containing a plurality of battery cells and provides a space filled with a fluid 3 having insulating properties, and an openable top cover 1-2 located at the top of the immersion tank so that the battery module can be pulled in.

[0141] A plurality of openings 2-6, 2-7, and 2-8 are provided on the outer surface of the battery module 2 to allow fluid to flow in and out of the inside of the battery module. A free space formed by an air layer having a certain depth D is provided at the upper part of the immersion tank.

[0142] As shown in Fig. 20(b), in one embodiment of the present invention, the periphery of the battery housing like immersion tank 100 is surrounded by vertical and horizontal reinforcing frames 110, 120, 140 to enhance structural safety. In addition, the top cover 1-2 of the immersion tank includes an explosion-proof disk 1-21 to quickly vent gas and pressure that may be generated due to failure of a battery cell. This explosion-proof disk is opened by a certain pressure to protect the immersion tank and the internal electrical equipment.

[0143] The top lid of the liquid immersion tank is provided with a filler port 19, so that the fluid 3 can be supplied to the inside without opening the tank cover 1-2.

[0144] 20(c), in one embodiment of the present invention, a frame surrounding the immersion tank is connected to a panel 211, and the panel and frame are joined to form a double-cased outer box using a gasket and a connecting member 252. This configuration is characterized by the fact that it protects the immersion tank housing the battery from the external environment (weather, tornadoes, etc.) and prevents contamination of the surrounding environment by containing any fluid leaking from the immersion tank.

[0145] Furthermore, a removable roof 201 is provided on the top to allow access to the inside of the outer box as needed. The roof is provided with side openings 1-22 to help dissipate heat from the inner space heated by solar heat.

[0146] The outer box ultimately transfers load to the ground via the base frame 303 and the support legs 305 .

[0147] As shown in (d) of Figure 20, in one embodiment of the present invention, a battery system is configured by integrating a liquid-immersion type battery system including an accessory box 1-1 and a heat exchanger 9 into a single space, that is, a housing 200.

[0148] The accessory box houses a BMS, various electrical safety devices, etc. The power and communication cables coming out of the battery system in the immersion tank 100 are connected to various devices in the accessory box via the accessory box access part 290.

[0149] It is also connected to the free space of the immersion tank and includes a pressure equalizing device 161 formed in the accessory space via the accessory box access part 290.

[0150] FIG. 21 shows a detailed cross-section of the outer box cross-section and main components configured by integrating an immersion-type battery system and a heat exchanger according to an embodiment of the present invention. In FIG. 21, some components are omitted for the sake of explanation.

[0151] As shown in FIG. 21(a), a draw-in distribution pipe 11 with a series of holes 13 of different sizes formed on the bottom surface of the immersion tank located inside the outer box is positioned so that the fluid to be drawn in is distributed at an equal flow rate.

[0152] FIG. 21(b) is a detailed cross-sectional view showing the outer box roof side opening 1-22, the rainwater inflow prevention partition 1-24, and the drain hole.

[0153] FIG. 21(c) is a detailed cross-sectional view showing the cross-section of the coupling structure between the frames 110, 120, 140 and the outer box panels 210, 211. A gasket 251 sandwiched between the frame and the panel is crimped using a coupling member 252 to form an outer box of a double housing type that protects the immersion tank 100.

[0154] FIG. 21(d) is a detailed cross-sectional view showing a drain pipe 222 composed of an openable and closable lock valve 223 and a tank fitting 221 formed at the bottom of the outer box.

[0155] 21(e) shows a housing 200 constructed by forming a perforated panel 15 and a flow control device 16 on the bottom surface of an immersion tank 100 according to an embodiment of the present invention. This internal configuration allows the fluid drawn into the tank to be distributed at an even flow rate as it moves toward the top of the tank.

[0156] In addition, the present invention is an immersion type battery system integrated with a housing, in which the space formed between the immersion tank 100 and the outer box panels 210, 211 includes insulation material 142 to protect the battery system from the external environment and improve thermal management performance and efficiency. [Explanation of symbols]

[0157] 1-1 Accessory box 1-2 Top lid 1-27 Volts 1-28 Nut 2 Battery Module 2-6, 2-7, 2-8 Opening or outlet 3 Fluids, immersion fluids 7 Circulation Pump 9 Heat exchanger 11 Intake distribution pipe 15 Perforated Panel 16 Flow Control Device 100 Immersion Tank 142 Insulation 161 Pressure equalizer 162 Oil level gauge 200 Outer box 201 Outer box roof 212 Fixing plate 218 Hinge 221 Tank Fitting 222 Drain piping 251 Gasket 252 Connecting members 290 Accessory box access

Claims

1. a battery module housing a plurality of battery cells; A fluid having insulating properties; a battery housing in the form of a liquid immersion tank that has a space for accommodating the battery module and is filled with the fluid to completely immerse the battery module; a plurality of openings on an outer surface of the battery module to allow the fluid to flow in and out of the interior of the battery module and directly contact the battery cells; an openable top cover provided on the immersion tank and located at an upper end of the immersion tank so that the battery module can be pulled into the inside of the immersion tank; A battery system of an immersion cooling type integrated with a housing, characterized in that it includes a free space provided in an upper portion of the immersion tank, forming an air layer of a certain depth.

2. a circulation pipe including an external circulation loop formed outside the immersion tank such that the fluid is drawn into the interior of the immersion tank and returned to the exterior; The battery system of claim 1 , further comprising: a circulation pump provided on the external circulation loop for circulating the fluid.

3. 3. The battery system of claim 2, wherein a heat exchanger located on the path of the external circulation loop includes a cooling section that cools the circulating fluid.

4. The battery system of claim 3 , wherein the heat exchanger includes a heating portion for heating the circulating fluid.

5. an intake distribution pipe that is provided on either an upper surface or a lower surface inside the immersion tank and distributes, inside the tank, the fluid that is discharged from the circulation pump and drawn into the inside of the immersion tank; a suction pipe that is provided on the remaining surface corresponding to the moving direction of the fluid to be drawn in and that is a pipe for sucking in the fluid in the immersion tank and returning it to the circulation pump; The battery system of the liquid immersion cooling type integrated with the housing described in claim 2, characterized in that the inlet distribution pipe and the suction pipe have a plurality of opening holes of different sizes arranged in a row in the longitudinal direction of the pipes so as to uniformly distribute or suck in the flow rate.

6. 3. The immersion cooling type battery system integrated with a housing as described in claim 2, further comprising a perforated panel provided on the underside of the immersion tank and having a plurality of holes that allow the fluid in the immersion tank to be evenly distributed and moved inside the immersion tank.

7. 7. The battery system of claim 6, wherein the fluid is distributed by forming a flow control device under the perforated panel, the flow control device providing an inclination from the starting end to the ending end to evenly distribute the flow rate moving therethrough.

8. 2. A battery system of an immersion cooling type integrated with a housing as described in claim 1, characterized in that it includes an oil level gauge formed on one outer surface of the immersion tank so that the position of the oil level abutting the bottom surface of the free space can be confirmed from the outside without opening the top lid of the immersion tank.

9. 9. The immersion cooling type battery system integrated with a housing as described in claim 8, further comprising an explosion-proof disk located on the top cover of the immersion tank and opening at a constant pressure to discharge gas and pressure discharged due to failure of a battery cell, thereby protecting the immersion tank and internal electrical equipment.

10. a plurality of reinforcing frames attached at appropriate positions around the immersion tank to structurally reinforce the immersion tank; A panel that connects the spaces between the reinforcing frames; 2. The battery system of claim 1, which is an immersion cooling type integrated with a housing, further comprising: an outer box which is a housing surrounding the immersion tank.

11. an accessory box located on one side of the outer box and mounted on a panel to house a battery management system or other electrical protection device; an oil level gauge for measuring the oil level of the fluid in the immersion tank; an accessory box access section provided on an upper portion of an outer case panel to which the accessory box is attached and on one side of the accessory box corresponding thereto, the accessory box access section being formed to fit a free space filled with an air layer at an upper portion inside the immersion tank, and allowing a power cable and a communication cable coming out of the immersion tank to access the inside of the accessory box; 11. The immersion cooling type battery system integrated with a housing as described in claim 10, characterized in that it includes a heat exchanger located on one side of the outer box, which is located on an external circulation loop line formed outside the immersion tank so that the fluid is drawn into the inside of the immersion tank and returned to the outside, and which exchanges thermal energy of the circulating fluid.

12. a plurality of lower openings provided on a bottom surface of the accessory box, through which cool outside air is drawn in to remove heat generated by the electrical devices in the accessory box; A plurality of louver-type upper end side openings formed at the upper end of the side of the accessory box so that the warm air can be sent out after the exchange of thermal energy; A mash net is provided on the inner surface of each opening to prevent external insects or foreign objects from entering through the opening; 12. The liquid immersion cooling type battery system integrated with a housing as described in claim 11, further comprising: a rainwater inflow prevention partition provided obliquely along the inner surface of the opening so as to block rainwater flowing into the interior through the louver-type upper side opening.

13. a drain pipe provided on a bottom surface of the immersion tank for draining the fluid contained in the immersion tank to the outside; A tank fitting that connects the drain pipe to an opening in the bottom panel of the outer box, The end of the drain pipe is finished with an open / close lock valve. The immersion cooling type battery system integrated with a housing as described in claim 10, characterized in that the drain piping comes out of the outer box through an opening hole provided in the bottom panel of the outer box at a position corresponding to the bottom surface of the immersion tank in which the piping is formed.

14. 11. The battery system of claim 10, which is integrated with a housing and has a liquid immersion cooling method, further comprising a fill port provided on an openable top cover at the top end of the liquid immersion tank, through which a fluid can be filled into the inside of the tank.

15. 11. The battery system of claim 10, further comprising an outer case roof provided on an upper end of the outer case and allowing access to the inside of the outer case.

16. The immersion cooling type battery system integrated with a housing as described in claim 10, further comprising an explosion-proof disk provided on an openable top cover at the top of the immersion tank, which opens at a certain pressure to quickly release gas and pressure emitted in the event of a failure of a battery cell located in the immersion tank, thereby protecting the immersion tank and internal devices.

17. a plurality of openings provided along the sides of the outer box roof for venting pressure and gas discharged from the explosion-proof disk to the outside; A mash net is provided on the inner surface of the opening to prevent external insects or foreign objects from entering through the opening; A rainwater inflow prevention partition is provided diagonally along the inner side surface of the opening to prevent rainwater flowing in through the opening from entering the interior; 17. The battery system of claim 15 or 16, which is integrated with a housing and has a liquid immersion cooling method, further comprising: a drainage hole for draining raindrops that are blocked and collected by the partition to the outside of the outer box.

18. a hinge connecting one side of the outer box roof and the outer box side panel; Fixing plates provided on both sides of the outer box; A bolt is fixed to the roof surface of the outer box at a position corresponding to the fixing plate; a groove provided in the fixing plate and formed along a path along which the bolt moves while the outer box roof is opened about the hinge; a nut coupled to the bolt for crimping the fixing plate and sliding along a groove of the fixing plate while the box roof is opened; 17. The battery system of claim 15 or 16, wherein a force applied to a nut that presses a fixing plate so that the roof of the outer box can be opened by a pressure discharged from the explosion-proof disk satisfies the following mathematical formula 1: [0010]

19. The outer box is 11. The battery system of claim 10, wherein the battery system is of a double housing type, in which a gasket is sandwiched between the contact surfaces of the reinforcing frame and the panel, and a connecting member is used to connect the panel, the reinforcing frame, and the gasket to each other, so that their abutting surfaces are compressed and fastened together.

20. The battery system of claim 10 , which is integrated with a housing and has a liquid immersion cooling method, further comprising: a heat insulating material that is accommodated in the empty space formed between the liquid immersion tank and the outer box panel to block the intrusion of external heat.

21. the immersion tank further includes a pressure equalization device disposed on a side wall of the immersion tank, the pressure equalization device being formed in accordance with a free space filled with an air layer in an upper portion of the immersion tank, so as to equalize a pressure difference caused by thermal expansion and contraction of a fluid; 11. The battery system of claim 10, wherein the pressure equalization device includes a desiccant that removes moisture from the air that flows in from the outside during the pressure equalization process.

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