Battery pack case with fire extinguishing function and battery pack equipped with same

Abstract

The battery pack case (100) of the present invention includes a case body (120) having an open side and capable of accommodating a plurality of battery modules (10) therein, and a case cover (110) for opening and closing the open side of the case body. The case cover (110) includes an outer casing (111) having one or more chambers sealed to have a predetermined volume of internal space and configured as a plate of a predetermined width, a plurality of spray nozzles (116) formed on the outer casing to respectively communicate with the internal spaces of the chambers in a direction facing the plurality of battery modules, and a plurality of sealing lids (117) made of a low-melting-point alloy filled and sealed in the plurality of spray nozzles, which melt at a predetermined temperature in the event of a fire in the battery so that the fire-extinguishing liquid is sprayed onto the battery through the spray nozzles.

Description

[Technical Field]

[0001] The present invention relates to a battery pack case that performs a fire extinguishing function in the event of a fire caused by thermal runaway of a battery cell, and more particularly to a battery pack case in which a case cover located on top of the battery pack simultaneously functions to seal the interior and to extinguish a fire caused by thermal runaway.

[0002] The present invention also relates to a battery pack including the battery pack case, and more particularly to a battery pack in which, in the event of a fire in the battery, a fire-extinguishing liquid stored in a fire-extinguishing liquid storage means is sprayed through a case cover located on the top of the battery pack to immerse the battery partially or entirely, thereby quickly cooling the battery cells or being absorbed into the battery cells to suppress internal thermal runaway reactions and prevent transfer to adjacent cells. [Background technology]

[0003] Recently, the number of battery-powered electric vehicles has increased rapidly. However, battery fires are occurring frequently, and fires caused by sparks or short circuits are almost unpredictable. Therefore, it is necessary to be prepared for fires.

[0004] Electric vehicle batteries are configured with multiple battery modules, each consisting of multiple battery cells connected together. If a fire breaks out in one battery cell, the fire can quickly spread to other connected battery cells or battery modules.

[0005] On the other hand, an ESS (Energy Storage System) is a storage device that stores excess electricity produced at power plants and transmits it when there is a temporary power shortage. Recently, large-scale ESS devices have been made smaller and are increasingly being used in general-use buildings, factories, homes, and other facilities to prepare for power outages or reduce peak power consumption.

[0006] Recently, interest in new renewable energy sources has been increasing rapidly due to the imbalance in power supply and demand, and there has been ongoing development of technology that uses ESS to store electricity produced using new renewable energy sources and use it when needed.

[0007] In particular, the ESS market continues to grow as the installation of ESS has recently become mandatory for newly constructed public buildings and the installation of ESS in private buildings as well is increasing as a means of energy conservation.

[0008] When installing an ESS in a building, the ESS battery rack (battery module) contains the batteries that store energy, the BMS that manages the batteries, and the PCS that converts power. Such battery racks are housed in a fixed space such as a basement and operated.

[0009] Generally, secondary batteries can be recharged and reused, and in recent years, lithium-ion batteries, which have high charge / discharge efficiency, have been widely used. Because lithium-ion batteries have a relatively small volume and high charge / discharge efficiency, they are increasingly being used in electric vehicles and ESS, as well as power plants, charging stations, and portable devices.

[0010] However, since a lithium-ion battery has a thin separator between the negative and positive electrode materials, the separator may be damaged by impact, or may be damaged by aging or by the growth of dendrites, causing a short circuit between the negative and positive electrode materials, resulting in a fire. In the case of large-scale equipment, this can cause enormous property damage.

[0011] Meanwhile, battery packs including battery modules use air-cooling or water-cooling technology to maintain an appropriate cell temperature, but when a battery cell experiences thermal runaway, proper temperature control is not possible, which can lead to the thermal runaway spreading to adjacent cells and causing the entire battery to catch fire, resulting in a serious fire.

[0012] Although there are many prior art documents that provide a separate fire extinguishing device inside a battery module or pack to extinguish a fire caused by such thermal runaway of a battery cell, there is a limit to the amount of fire extinguishing liquid that can be contained within the battery module or pack due to space and structural constraints. Also, the prior art documents have a structure that sprays a small amount of fire extinguishing liquid at a specific position, which is never enough to extinguish a fire in an actual battery, and because the battery cells are in close contact with each other, the fire extinguishing liquid cannot fully contact the battery cell where the fire has occurred, which causes problems such as the fire spreading to adjacent cells. Summary of the Invention [Problem to be solved by the invention]

[0013] Therefore, the present invention has been made to solve the problems of the prior art described above, and its object is to provide a battery pack case and a battery pack equipped with the same, in which the battery pack case cover is configured as an integrated fire extinguishing plate, and in the event of thermal runaway in a specific cell or module, a large amount of fire extinguishing liquid is sprayed intensively onto the battery, effectively extinguishing the fire and preventing it from spreading to adjacent cells.

[0014] Another object of the present invention is to provide a battery pack in which, in the event of a fire in the battery, fire extinguishing liquid stored in a fire extinguishing liquid storage means is sprayed through a case cover located on the top of the battery pack so that the battery is partially or entirely submerged, thereby quickly cooling the battery cells or being absorbed into the battery cells, suppressing internal thermal runaway reactions and preventing transfer to adjacent cells. [Means for solving the problem]

[0015] In order to achieve the above object, the present invention provides a battery pack case that can accommodate a plurality of battery modules therein and includes: a case body having an opening on one side; and a case cover that opens and closes the opening on the one side of the case body, wherein the case cover includes an outer casing having one or more chambers sealed to have a predetermined volume of internal space, the chambers being formed in a plate shape with a predetermined width; a fire extinguishing liquid that is filled with a predetermined amount of the internal space of the chambers at a predetermined injection pressure; a plurality of injection nozzles formed on the outer casing so as to respectively communicate with the internal space of the chambers in a direction facing the plurality of battery modules; and a low-melting-point alloy (fusible alloy) that is filled and sealed in the plurality of injection nozzles and melts at a predetermined temperature when a fire occurs in the battery, thereby injecting the fire extinguishing liquid onto the battery through the injection nozzles. and a plurality of sealing lids made of a low-melting-point alloy, wherein the outer shaping means includes upper and lower plates each made of a metal material, formed along an edge, and welded together along the edge to form a certain internal space, wherein the upper and lower plates each have a plurality of formed portions that are formed to protrude inward and welded together between the top and bottom so that their ends come into surface contact when they are brought into close contact with each other, and the spray nozzle is formed integrally with the lower plate by forming a hole with a portion of the lower plate protruding further outward, and a thread tap is machined on the inner surface of the spray nozzle to further strengthen the bonding strength between the sealing lid made of a low-melting-point alloy and the inner surface of the spray nozzle.

[0016] The lower plate may further include a separate insulating coating layer or an insulating pad for insulation from the terminals inside the battery pack. The constant ejection pressure of the fire extinguishing liquid can be achieved by filling the inner space of the chamber with compressed air or nitrogen gas.

[0017] In order to achieve the above object, the present invention provides a battery pack including a plurality of battery modules and a case for accommodating the plurality of battery modules, the case including a case body capable of accommodating the plurality of battery modules therein and having an opening on one side, and a case cover for opening and closing the opening on the one side of the case body, the case cover being configured as described above.

[0018] The battery pack may further include a fire extinguishing liquid storage means for storing a fire extinguishing liquid at a certain ejection pressure to the extent that all or some of the battery modules in the case can be submerged, and supplying the fire extinguishing liquid into the case in the event of a battery fire.

[0019] It is preferable that the case body has a partition structure therein that is divided into multiple sections so that the multiple battery modules can be accommodated in their respective separated spaces, and it is more preferable that the partitions of the case body are configured to have a height that is lower than the edge of the case body.

[0020] The battery module may include a number of stacked battery cells and a number of porous absorbent pads disposed between the battery cells. It is preferable that the extinguishing liquid storage means is connected to one side of the external means through a communication line, and the extinguishing liquid stored in the extinguishing liquid storage means is sprayed toward the battery where the fire has occurred through the external means and the open outlet of the spray nozzle.

[0021] The constant ejection pressure of the fire extinguishing liquid in the fire extinguishing liquid storage means and the case cover can be achieved by filling the respective internal spaces with compressed air or nitrogen gas. [Effects of the Invention]

[0022] The present invention has the effect of configuring the battery pack case cover as an integrated fire extinguishing plate, so that in the event of thermal runaway in a specific cell or module, a large amount of fire extinguishing liquid can be concentrated and sprayed onto the battery, effectively suppressing the fire and preventing it from spreading to adjacent cells.

[0023] In addition, in the event of a fire in the battery, the present invention sprays the fire-extinguishing liquid stored in the fire-extinguishing liquid storage means through the case cover located on top of the battery pack, so that the battery is partially or entirely submerged, and the fire-extinguishing liquid quickly cools the battery cells or is absorbed into the battery cells, suppressing internal thermal runaway reactions and preventing transfer to adjacent cells.

[0024] That is, in the present invention, the extinguishing liquid stored in the case cover located on the top of the battery pack is sprayed primarily onto the fire site to quickly extinguish the flames, and the extinguishing liquid stored in the extinguishing liquid storage means is sprayed secondarily into the case so that the battery is partially or entirely immersed in the extinguishing liquid, thereby allowing the extinguishing liquid to be absorbed into the battery cell, suppressing the internal thermal runaway reaction and preventing it from transferring to adjacent cells.

[0025] Specifically, in the present invention, when a battery fire causes a temperature rise, the temperature of the spray nozzle of the case cover closest to the battery where the fire occurred rises, and the low-melting-point alloy sealing the nozzle outlet melts at a predetermined temperature, opening the nozzle outlet. Fire-extinguishing fluid contained in the internal space of the chamber of the case cover is primarily sprayed at a certain pressure toward the battery where the fire occurred through the opened outlet, thereby enabling initial fire extinguishing of the battery where the fire occurred. The fire-extinguishing fluid stored in the fire-extinguishing fluid storage means then passes through the case cover and is secondarily sprayed toward the battery where the fire occurred through the opened nozzle outlet, thereby immersing the battery module where the fire occurred partially or entirely in the fire-extinguishing fluid, which is absorbed into the battery cell and suppresses internal thermal runaway reactions and prevents the spread of the fire to adjacent cells. Furthermore, if the fire-extinguishing fluid overflows the partition wall of the battery module where the fire occurred, it can fill the separation space between adjacent battery modules to prevent the spread of flame and heat to adjacent cells. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic perspective view showing the structural relationship of a battery pack including a battery pack case having a fire extinguishing function according to a first embodiment of the present invention. FIG. [Figure 2] 1 is a cross-sectional view showing the structural relationship of a battery pack including a battery pack case having a fire extinguishing function according to a first embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view of the battery pack case having a fire extinguishing function shown in FIG. 1. [Figure 4] FIG. 4 is an enlarged cross-sectional view of part A shown in FIG. 3. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of a battery pack including a battery pack case having a fire extinguishing function according to a second embodiment of the present invention. [Figure 6] 6 is a schematic diagram showing the structural relationship of the battery module shown in FIG. 5 and the circulation process of the fire-extinguishing liquid. [Figure 7] FIG. 6 is a perspective view showing the structural relationship of the case body shown in FIG. 5. [Figure 8] 8 is a plan view showing a state in which a battery module is arranged within a partition wall of a case body shown in FIG. 7. FIG. [Figure 9] 6 is a cross-sectional view showing the structural relationship of the case cover shown in FIG. 5. [Figure 10] FIG. 10 is an enlarged cross-sectional view of part B shown in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0027] The battery pack case with fire extinguishing function of the present invention is arranged in contact with or adjacent to a battery of an electric vehicle, ESS, etc., and is used to extinguish a fire that occurs in the battery. The battery pack of the present invention is applicable to electric vehicles, ESS, etc., and is configured to extinguish a fire that occurs in the battery.

[0028] Hereinafter, preferred embodiments of a battery pack case with a fire extinguishing function and a battery pack including the same according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments disclosed below and may be embodied in various different forms. However, the present embodiments are provided to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0029] [First embodiment] 1 and 2 are a schematic perspective view and a cross-sectional view showing the structural relationship of a battery pack including a battery pack case with a fire extinguishing function according to a first embodiment of the present invention, FIG. 3 is a horizontal cross-sectional view of the battery pack case with a fire extinguishing function shown in FIG. 1, and FIG. 4 is an enlarged cross-sectional view of part A shown in FIG. 3.

[0030] As shown in FIGS. 1 to 4, the battery pack according to this embodiment includes a number of battery modules 10 and a case 100 that houses the number of battery modules 10.

[0031] The battery module 10 is a component that generates electrochemical energy through the movement of ions or electrons, and may be arranged in multiple numbers inside the case 100. The battery modules 10 may be arranged in multiple rows and columns inside the case 100. One battery module 10 may include multiple stacked battery cells, and each battery cell may include a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. The battery module 10 may include a protection circuit module provided in each battery cell or integrally connected to multiple battery cells, and the protection circuit module may control the voltage or current during charging and discharging of the battery cell. Each battery cell may have an electrode tab drawn out, and the electrode assembly may be of any known type, such as a stacked type or a wound type.

[0032] The case 100 is a member that accommodates a plurality of battery modules 10 therein and may include a case body 120 and a case cover 110. Here, the case body 120 can accommodate a plurality of battery modules 10 therein and may have a box shape with one side open, and the case cover 110 can open and close the open side of the case body 120. Therefore, when the case cover 110 is closed on the case body 120, the inside of the case can be protected from the external environment.

[0033] The case cover 110 is configured to simultaneously have the function of sealing the inside of the case body 120 and the function of extinguishing a fire caused by thermal runaway. That is, the case cover 110 is configured as an integrated fire extinguishing plate, and is configured to inject a large amount of fire extinguishing liquid intensively into the battery when thermal runaway occurs in a specific cell or module, thereby effectively extinguishing the fire and preventing it from spreading to adjacent cells.

[0034] Such a case cover 110 extinguishes the fire by spraying the extinguishing liquid contained therein at the location of the fire when a fire occurs in a battery (specific cell or module). The case cover 110 includes an outer casing 111 having a plate-shaped chamber with a certain width and sealed to have a certain internal volume; a certain amount of extinguishing liquid (not shown) that fills the internal space of the chamber with a certain spray pressure; a plurality of spray nozzles 116 formed on the outer casing 111 so as to communicate with the internal space of the chamber in a direction facing the plurality of battery modules 10; and a plurality of sealing lids 117 made of a low-melting-point alloy that is filled and sealed inside the plurality of spray nozzles 116 and melts when heated above a certain temperature during thermal runaway of the battery, thereby spraying the extinguishing liquid onto the battery through the spray nozzles 116.

[0035] The exterior means 111 serves as a frame that constitutes the exterior of the case cover 110 and is composed of an upper plate 112 and a lower plate 114 that are press-formed along their edges and welded together along their edges to form a certain internal space. In this embodiment, the upper plate 112 and the lower plate 114 are made of a metal material such as stainless steel or aluminum, and preferably have a thickness of 0.2 to 1.0 mm in consideration of rigidity and weight reduction. Meanwhile, the overall thickness of the case cover 110 is preferably between 3 to 10 mm in consideration of the capacity of the fire extinguishing liquid and the vehicle structure and weight.

[0036] 3, the upper plate 112 and the lower plate 114 are configured to have a number of forming portions 113, 115 that are press-formed into an embossed shape so as to protrude inward. Here, the upper plate 112 and the lower plate 114 are configured to have the same forming portions 113, 115, and when they are brought into close contact with each other, the ends of the forming portions 113, 115 come into surface contact with each other. The edges of the upper plate 112 and the lower plate 114 that are press-formed into an embossed shape and the forming portions 113, 115 are welded to each other, respectively, to ensure rigidity that prevents expansion and deformation due to high-pressure extinguishing fluid inside and to seal the extinguishing fluid from leaking.

[0037] As shown in FIG. 4, the lower plate 114 faces the inside of the battery pack, i.e., the multiple battery modules 10, and is equipped with multiple heat-sensitive spray nozzles 116. In the event of a battery fire, a fire-extinguishing liquid is automatically sprayed through the spray nozzles 116 as the internal temperature of the battery module or pack rises. Here, the heat-sensitive type is such that the spray nozzles 116 are formed on the lower plate 114 and have sealing covers 117 sealed with a low-melting-point alloy that melts at low temperatures (60 to 150°C). When the internal temperature of the battery pack reaches a predetermined temperature, the low-melting-point alloy melts, opening the spray nozzles and spraying high-pressure fire-extinguishing liquid through the outlets of the spray nozzles 116. The low-melting-point alloy in this embodiment may be composed of a mixture of elements such as bismuth, lead, tin, indium, cadmium, and gallium.

[0038] Meanwhile, the injection nozzle 116 is formed integrally with the lower plate 114 by forming a hole with a portion of the lower plate 114 protruding further outward through a burring process when press-forming the lower plate 114 into an embossed shape. That is, the injection nozzle 116 of this embodiment is formed integrally with the lower plate 114 without the need for a separate plug for nozzle fabrication, thereby reducing manufacturing costs and thickness. Here, it is preferable that the inner diameter of the injection nozzle 116 is 2 to 5 mm and the height is 2 to 5 mm, taking into consideration sealing strength and injection speed.

[0039] In this embodiment, the case cover 110 has a configuration in which the internal space of the chamber is filled with a certain amount of fire-extinguishing liquid at a certain spray pressure. Therefore, even if the low-melting-point alloy constituting the sealing cover 117 is not melted by external heat such as a fire, the spray pressure of the fire-extinguishing liquid must not cause the sealing lid 117 sealing the outlet of the injection nozzle 116 to separate from the outlet. However, as can be seen from FIG. 4, the injection nozzle 116 of this embodiment has a curved tapered shape at the top during the burring process, so that the sealing lid 117 sealing the outlet of the injection nozzle 116 is not likely to separate from the outlet due to the spray pressure of the fire-extinguishing liquid. However, it is more preferable to machine a threaded tap on the inner surface of the injection nozzle 116 as shown in FIG. 4(b) to further strengthen the bonding strength between the low-melting-point alloy sealing lid 117 and the inner surface of the injection nozzle 116, thereby enabling the injection nozzle 116 to withstand higher spray pressures of the fire-extinguishing liquid.

[0040] In addition, the lower plate 114 may be further configured by attaching a separate insulating coating layer or insulating pad for insulation from terminals such as bus bars inside the battery pack.

[0041] Meanwhile, in this embodiment, the internal space of the chamber is filled with a certain amount of fire-extinguishing liquid so as to have a certain ejection pressure. To accommodate the fire-extinguishing liquid at a certain ejection pressure, the internal space of the chamber may be filled with compressed air or nitrogen gas. That is, a communication port (not shown) communicating with the internal space of the chamber, for example, a communication port is formed at one location on one side of the upper plate 112, and a vacuum is drawn in the internal space of the chamber through this communication port. A certain amount of fire-extinguishing liquid is then filled into the internal space of the chamber at the vacuum pressure, and compressed air or nitrogen gas is then filled in, thereby filling the internal space of the chamber with the fire-extinguishing liquid at a certain ejection pressure. Therefore, when the outlet of the injection nozzle 116 is opened, the fire-extinguishing liquid is sprayed toward the battery by its own ejection pressure. Meanwhile, the fire-extinguishing liquid is a chemical that reacts with the flame and evaporates, extinguishing the fire by the cooling effect due to the latent heat of vaporization, and its ejection pressure (internal pressure) is 5 to 10 kgf / cm. 2 It is preferable to install it in the internal space of the chamber so that the pressure therein is (0.490 to 0.981 MPa).

[0042] The extinguishing liquid is preferably an agent that evaporates easily even at low temperatures to have a cooling effect, and it is more preferable to use a fluorine-based ketone (FK-5-1-12, dodecafluoro-2-methylpentan-3-one) that also has insulating properties. Water, which has an excellent latent heat of vaporization, can also be sprayed in mist form, and enhanced liquid extinguishing agents can also be used, and they can also be mixed and used.

[0043] In this embodiment, the outer means 111 is configured with one chamber, but it may also be configured with multiple chambers each having an internal space sealed and partitioned from each other. In this case, the number of chambers can be changed according to the application environment.

[0044] The case cover 110 of this embodiment configured as described above is capable of initially suppressing a battery fire. That is, when a battery fire occurs and temperature rises, the temperature of the spray nozzle 116 closest to the battery where the fire has occurred rises, and the low-melting-point alloy sealing the outlet of that spray nozzle 116 melts at a predetermined temperature, opening the outlet of that spray nozzle 116. The fire-extinguishing liquid contained in the internal space of the chamber is sprayed through the opened outlet at a certain spray pressure toward the battery where the fire has occurred, thereby enabling initial fire suppression of the battery where the fire has occurred.

[0045] Meanwhile, the case cover 110 of this embodiment may be configured to further include a pressure gauge (not shown) for measuring the pressure inside the chamber. Also, the case cover 110 of this embodiment may be configured to be connected to a tank storing a separate fire extinguishing liquid, thereby spraying the fire extinguishing liquid stored inside the chamber and in the tank to the fire site, thereby enabling more efficient fire suppression.

[0046] The case cover 110 of this embodiment configured as described above is arranged in contact with or adjacent to the battery of an electric vehicle, ESS, etc., and can be used to extinguish a fire in the event of a fire occurring in the battery.

[0047] [Second embodiment] FIG. 5 is a schematic diagram showing the structural relationship of a battery pack equipped with a battery pack case having a fire extinguishing function according to a second embodiment of the present invention; FIG. 6 is a schematic diagram showing the structural relationship of the battery module shown in FIG. 5 and the circulation process of the fire extinguishing liquid; FIG. 7 is a perspective view showing the structural relationship of the case body shown in FIG. 5; FIG. 8 is a plan view of the state in which the battery module is arranged within the partition of the case body shown in FIG. 7; FIG. 9 is a cross-sectional view showing the structural relationship of the case cover shown in FIG. 5; and FIG. 10 is an enlarged cross-sectional view of part B shown in FIG. 9.

[0048] As shown in FIGS. 5 to 10, a battery pack equipped with a battery pack case having a fire extinguishing function according to the second embodiment of the present invention includes a number of battery modules 10, a case 200 that houses the number of battery modules 10 in their respective separation spaces, and a fire extinguishing liquid storage means 300 that stores a certain amount of fire extinguishing liquid at a certain ejection pressure so that all or some of the number of battery modules 10 in the case 200 can be immersed in the fire extinguishing liquid, and supplies the fire extinguishing liquid into the case 200.

[0049] The battery module 10 is a component that generates electrochemical energy through the movement of ions or electrons, and may be arranged in multiple numbers inside the case 200. The battery modules 10 may be arranged in multiple rows and columns inside the case 200 (see FIG. 8). As shown in FIG. 6, one battery module 10 may include multiple stacked battery cells 11, and each battery cell 11 may include a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. The battery module 10 may include a protection circuit module provided in each battery cell 11 or a protection circuit module integrally connected to multiple battery cells, and the protection circuit module may control the voltage or current during charging and discharging of the battery cells 11. Electrode tabs may be drawn out from each battery cell 11, and the electrode assembly may be of any known type, such as a stacked type or a wound type.

[0050] Furthermore, as shown in FIG. 6 , the battery module 10 may include a number of porous absorbent pads 12 disposed between the battery cells 11. The porous absorbent pads 12 are preferably made of a non-flammable material with capillary force that allows them to absorb fire-extinguishing liquid even when both sides of the porous absorbent pad are in close contact with the battery cells 11. Such non-flammable materials may include inorganic fiber materials such as glass wool and ceramic wool, or granular inorganic materials such as silica and activated carbon, or a mixture of inorganic materials and heat-resistant silicone. By providing such porous absorbent pads 12 between the battery cells 11, it is possible to cool the battery more efficiently in the event of a fire and extinguish the fire, as well as prevent the spread of flames and heat to adjacent cells.

[0051] The case 200 is a component that accommodates a number of battery modules 10 in their respective separation spaces and may include a case body 220 and a case cover 210. The case body 220 is box-shaped with one side open and is configured with a partition structure divided into multiple sections so that a number of battery modules 10 can be accommodated in each separation space (see FIGS. 7 and 8). Therefore, the fire-extinguishing liquid is primarily filled only in the separation space of the battery module 10 that has caught fire, and can immerse the entire or partial battery module 10 therein (see FIG. 5). Meanwhile, the partition wall 221 of the case body 220 may be configured to be lower than the edge of the case body 220. In this case, the fire-extinguishing liquid is primarily filled in the separation space of the ignited battery module 10 to extinguish the fire, and if it overflows the partition wall 221, it can also fill the separation space of the adjacent battery module 10 to prevent the spread of flame and heat to adjacent cells.

[0052] The case cover 210 can open and close the open side of the case body 220. Therefore, when the case cover 210 is closed on the case body 220, the inside of the case 200 can be protected from the external environment.

[0053] Furthermore, case cover 210 is configured to simultaneously have the function of sealing the inside of case body 220 and the function of extinguishing a fire caused by thermal runaway. That is, case cover 210 is configured with an integrated fire extinguishing plate, and is configured to intensively spray a large amount of fire extinguishing liquid onto a specific cell or module when thermal runaway occurs, thereby effectively extinguishing the fire and preventing it from spreading to adjacent cells.

[0054] Such a case cover 210 extinguishes the fire when a fire occurs in a battery (specific cell or module) by spraying the fire-extinguishing liquid contained therein at the location where the fire has occurred. The case cover 210 includes an exterior means 211 in the shape of a plate with a certain width and a sealed chamber with a certain internal volume; fire-extinguishing liquid that fills the internal space of the chamber with a certain amount at a certain spray pressure; a plurality of spray nozzles 216 formed on the exterior means 211 so as to communicate with the internal space of the chamber in a direction facing the plurality of battery modules 10; and a plurality of sealing lids 217 made of a low-melting-point alloy that is filled and sealed inside the plurality of spray nozzles 216 and melts when heated above a certain temperature during thermal runaway of the battery, thereby spraying the fire-extinguishing liquid onto the battery through the spray nozzles 216.

[0055] The exterior means 211, which serves as a frame that constitutes the exterior of the case cover 210, is composed of an upper plate 212 and a lower plate 214 that are press-formed along their edges and welded together along their edges to form a certain internal space. In this embodiment, the upper plate 212 and the lower plate 214 are made of a metal material such as stainless steel or aluminum, and preferably have a thickness of 0.2 to 1.0 mm in consideration of rigidity and weight reduction. Meanwhile, the total thickness of the case cover 210 is preferably 3 to 10 mm in consideration of the capacity of the fire extinguishing liquid and the vehicle structure and weight.

[0056] 9, the upper plate 212 and the lower plate 214 are configured to have a number of forming portions 213, 215 that are press-formed into an embossed shape so as to protrude inward. Here, the upper plate 212 and the lower plate 214 are configured to have the same forming portions 213, 215, and when they are brought into close contact with each other, the ends of the forming portions 213, 215 come into surface contact with each other. The edges of the upper plate 212 and the lower plate 214 that are press-formed into an embossed shape and the forming portions 213, 215 are welded to each other, respectively, to ensure rigidity that prevents expansion and deformation due to high-pressure extinguishing fluid inside and to seal the extinguishing fluid from leaking.

[0057] 10 , the lower plate 214 faces the inside of the battery pack, i.e., the multiple battery modules 10, and is equipped with multiple heat-sensitive spray nozzles 216. In the event of a battery fire, the fire-extinguishing liquid is automatically sprayed through the spray nozzles 216 as the internal temperature of the battery module or pack rises. Here, the heat-sensitive type is such that the lower plate 214 is provided with a spray nozzle 216 having a sealing cover 217 sealed with a low-melting-point alloy that melts at low temperatures (60 to 150°C). When the internal temperature of the battery pack reaches a predetermined temperature, the low-melting-point alloy melts, opening the spray nozzle 216 and spraying high-pressure fire-extinguishing liquid through the outlet of the spray nozzle 216. The low-melting-point alloy in this embodiment may be composed of a mixture of elements such as bismuth, lead, tin, indium, cadmium, and gallium.

[0058] Meanwhile, the injection nozzle 216 is formed integrally with the lower plate 214 by forming a hole with a portion of the lower plate 214 protruding further outward through a burring process when press-forming the lower plate 214 into an embossed shape. That is, the injection nozzle 216 of this embodiment is formed integrally with the lower plate 214 without the need for a separate plug for nozzle fabrication, thereby reducing manufacturing costs and thickness. Here, it is preferable that the inner diameter of the injection nozzle 216 is 2 to 5 mm and the height is 2 to 5 mm, taking into consideration sealing strength and injection speed.

[0059] In this embodiment, the case cover 210 has a configuration in which the internal space of the chamber is filled with a certain amount of fire-extinguishing liquid at a certain spray pressure. Therefore, even if the low-melting-point alloy constituting the sealing cover 217 is not melted by external heat such as a fire, the sealing cover 217 sealing the outlet of the injection nozzle 216 must not be separated from the outlet due to the spray pressure of the fire-extinguishing liquid. However, as can be seen from FIG. 10 , the injection nozzle 216 in this embodiment has a curved tapered upper portion during the burring process, so that the sealing cover 217 sealing the outlet of the injection nozzle 216 is not likely to be separated from the outlet due to the spray pressure of the fire-extinguishing liquid. However, it is more preferable to machine a threaded tap on the inner surface of the injection nozzle 216 as shown in FIG. 10 (b) to further strengthen the bonding strength between the low-melting-point alloy sealing cover 217 and the inner surface of the injection nozzle 216, thereby enabling the injection nozzle 216 to withstand higher spray pressures of the fire-extinguishing liquid.

[0060] In addition, the lower plate 214 may be further configured to have a separate insulating coating layer or insulating pad attached thereto for insulation from terminals such as bus bars inside the battery pack. Meanwhile, in this embodiment, the internal space of the chamber is filled with a certain amount of fire-extinguishing liquid so as to have a certain ejection pressure. To accommodate the fire-extinguishing liquid at a certain ejection pressure, the internal space of the chamber may be filled with compressed air or nitrogen gas. That is, a communication port (not shown) communicating with the internal space of the chamber, for example, a communication port is formed at one location on one side of the upper plate 212, and a vacuum is drawn in the internal space of the chamber through this communication port. Then, a certain amount of fire-extinguishing liquid is filled into the internal space of the chamber at the vacuum pressure, and compressed air or nitrogen gas is then filled in, thereby filling the internal space of the chamber with fire-extinguishing liquid at a certain ejection pressure. Therefore, when the outlet of the injection nozzle 216 is opened, the fire-extinguishing liquid is sprayed toward the battery by its own ejection pressure. Meanwhile, the fire-extinguishing liquid is a chemical that reacts with the flame to evaporate, thereby extinguishing the fire by the cooling effect due to the latent heat of vaporization, and its ejection pressure (internal pressure) is 5 to 10 kgf / cm. 2 It is preferable to install it in the internal space of the chamber so that the pressure therein is (0.490 to 0.981 MPa).

[0061] The extinguishing liquid is preferably a chemical that has the property of easily evaporating even at low temperatures due to its latent heat of evaporation cooling effect, and is preferably a fluorinated ketone (CF 12 It is more preferable to use fluorine-containing ketones such as FK-5-1-1, dodecafluoro-2-methylpentan-3-one.

[0062] In this embodiment, the outer casing 211 is configured with one chamber, but it may be configured with multiple chambers each having an internal space sealed and partitioned from each other. In this case, the number of chambers can be changed depending on the application environment. Meanwhile, the case cover 210 of this embodiment may be configured to further include a pressure gauge (not shown) for measuring the pressure inside the chamber.

[0063] As shown in FIG. 5, the fire extinguishing liquid storage means 300 stores a certain volume of fire extinguishing liquid at a certain ejection pressure and supplies it into the case 200 in the event of a fire in the battery, and is connected to one side of the external means 211 of the case cover 210 via a communication line.

[0064] The fire extinguishing liquid storage means 300 has a structure in which a certain amount of fire extinguishing liquid is filled in the tank so that the liquid has the same constant ejection pressure as the inside of the case cover 210. In this case, in order to store the fire extinguishing liquid so that the liquid has a certain ejection pressure, the internal space of the tank may be filled with compressed air or nitrogen gas. The fire extinguishing liquid in the fire extinguishing liquid storage means 300 is a fluorinated ketone (CF) that has the same insulating properties as the fire extinguishing liquid in the case cover 210. 12 In the event of a fire occurring in a battery (specific cell or module), such a fire extinguishing liquid storage means 300 sprays the stored fire extinguishing liquid to the fire site via the case cover 210, thereby more reliably suppressing the fire.

[0065] The battery pack of this embodiment is configured to first inject the fire-extinguishing liquid stored in the case cover 210 onto the fire site to quickly extinguish the flames, and then secondarily inject the fire-extinguishing liquid stored in the fire-extinguishing liquid storage means 300 onto the fire site via the case cover 210 so that the battery is partially or entirely immersed in the fire-extinguishing liquid, causing the fire-extinguishing liquid to be absorbed into the battery cells 11, suppressing internal thermal runaway reactions and preventing transfer to adjacent cells. Meanwhile, the battery pack of this embodiment is configured to have a vent valve (not shown) in the case body 220, similar to a general battery pack, and in the event of a fire in the battery, the vent valve opens, allowing for smooth injection of the fire-extinguishing liquid without being affected by the internal pressure of the case 200.

[0066] The battery pack of this embodiment configured as described above is capable of not only initial suppression of a fire in a battery but also suppressing a thermal runaway reaction and preventing the spread of the fire to adjacent cells. That is, when a battery fire occurs and temperature rises, the temperature of the spray nozzle 216 of the case cover 210 closest to the battery where the fire occurred rises, and the low-melting-point alloy sealing the outlet of the spray nozzle 216 melts at a predetermined temperature, opening the outlet of the spray nozzle 216. The fire-extinguishing liquid contained in the internal space of the chamber of the case cover 210 is sprayed primarily toward the battery where the fire occurred at a certain spray pressure through the opened outlet, thereby enabling initial fire suppression of the battery where the fire occurred. Thereafter, the fire extinguishing liquid stored in the fire extinguishing liquid storage means 300 is secondarily sprayed toward the battery where the fire has occurred through the opened outlet of the spray nozzle 216 via the case cover 210, so that the battery module 10 where the fire has occurred is partially or entirely immersed in the fire extinguishing liquid, and the fire extinguishing liquid is absorbed into the battery cell 11 to suppress the internal thermal runaway reaction and prevent it from being transferred to adjacent cells. Furthermore, if the fire extinguishing liquid overflows over the partition wall 221 of the battery module 10 where the fire has occurred, it can also fill the separation space between the adjacent battery modules 10, thereby preventing the spread of flame and heat to the adjacent cells.

[0067] The technical details of the battery pack case with a fire extinguishing function and the battery pack including the same according to the present invention have been described above with reference to the accompanying drawings, which illustrate the most preferred embodiments of the present invention. Therefore, the present invention is not limited to the above embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention, as would be obvious to those skilled in the art. Therefore, such modifications and variations should also be considered to fall within the scope of the present invention. [Industrial Applicability]

[0068] The present invention is applicable to electric vehicles, ESS, and the like, and can be used to extinguish fires that occur in batteries.

Claims

1. A battery pack case that can accommodate a plurality of battery modules therein, the battery pack case including: a case body having an opening on one side; and a case cover that opens and closes the opening on the one side of the case body, The case cover is an outer shape means configured as a plate of a certain width and having one or more sealed chambers each having a certain volume of interior space; a fire extinguishing liquid that is filled in the internal space of the chamber at a constant ejection pressure; a plurality of spray nozzles formed on the outer periphery of the chamber in a direction facing the plurality of battery modules; a plurality of sealing covers made of a low melting point alloy that is filled and sealed inside the plurality of spray nozzles, respectively, and melts at a certain temperature when a fire occurs in the battery, thereby spraying the fire-extinguishing liquid onto the battery through the spray nozzles; the outer shaping means includes an upper plate and a lower plate, each made of a metal material, formed along its edge, and welded together along its edge to form a predetermined internal space; the upper plate and the lower plate each have a plurality of forming portions that are formed to protrude inward so that ends thereof come into surface contact with each other when the upper plate and the lower plate are brought into close contact with each other, and are welded to each other between the top and bottom, the injection nozzle is integrally formed with the lower plate by forming a hole with a portion of the lower plate further protruding outward, and a thread tap is machined on an inner surface of the injection nozzle to further strengthen a bonding force between the sealing cover made of a low melting point alloy and the inner surface of the injection nozzle.

2. The battery pack case according to claim 1 , wherein the lower plate further comprises a separate insulating coating layer or an insulating pad for insulation from a terminal inside the battery pack.

3. The battery pack case according to claim 1 , wherein the constant ejection pressure of the fire-extinguishing liquid is achieved by filling the inner space of the chamber with compressed air or nitrogen gas.

4. A battery pack including a number of battery modules and a case that houses the number of battery modules, the case includes a case body having an opening at one side thereof, and a case cover for opening and closing the opening at the one side of the case body, the case body being capable of accommodating the plurality of battery modules therein; The case cover is an outer shape means configured as a plate of a certain width and having one or more sealed chambers each having a certain volume of interior space; a fire extinguishing liquid that is filled in the internal space of the chamber at a constant ejection pressure; a plurality of spray nozzles formed on the outer periphery of the chamber in a direction facing the plurality of battery modules; a plurality of sealing covers made of a low melting point alloy that is filled and sealed inside the plurality of spray nozzles, respectively, and melts at a certain temperature when a fire occurs in the battery, thereby spraying the fire-extinguishing liquid onto the battery through the spray nozzles; the outer shaping means includes an upper plate and a lower plate, each made of a metal material, formed along its edge, and welded together along its edge to form a predetermined internal space; the upper plate and the lower plate each have a plurality of forming portions that are formed to protrude inward so that ends thereof come into surface contact with each other when the upper plate and the lower plate are brought into close contact with each other, and are welded to each other between the top and bottom, the injection nozzle is integrally formed with the lower plate by forming a hole with a portion of the lower plate further protruding outward, and a thread tap is machined on an inner surface of the injection nozzle to further strengthen a bonding force between the sealing cover made of a low melting point alloy and the inner surface of the injection nozzle.

5. 5. The battery pack according to claim 4, further comprising a fire-extinguishing liquid storage means for storing a fire-extinguishing liquid at a certain ejection pressure in an amount sufficient to immerse all or some of the battery modules in the case, and supplying the fire-extinguishing liquid into the case in the event of a battery fire.

6. 6. The battery pack according to claim 5, wherein the case body has a partition structure therein that is divided into a plurality of sections so that the plurality of battery modules can be accommodated in respective separated spaces.

7. The battery pack according to claim 6, wherein the partition wall of the case body has a height lower than an edge of the case body.

8. 6. The battery pack according to claim 5, wherein the battery module includes a plurality of stacked battery cells and a plurality of porous absorbent pads disposed between the plurality of battery cells.

9. 6. The battery pack according to claim 5, wherein the extinguishing liquid storage means is in communication with one side of the outer means through a communication line, and the extinguishing liquid stored in the extinguishing liquid storage means is sprayed toward the battery in which the fire has occurred through the outer means and the open outlet of the spray nozzle.

10. 6. The battery pack according to claim 5, wherein the constant ejection pressure of the fire extinguishing liquid in the fire extinguishing liquid storage means and the case cover is achieved by filling the respective internal spaces with compressed air or nitrogen gas.

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