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

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 when a fire occurs due to thermal runaway of a battery cell. More specifically, the present invention relates to a battery pack case that simultaneously has a function of sealing the inside by a case cover located on the upper part of the battery pack and a fire extinguishing function of suppressing a fire caused by thermal runaway.

[0002] Furthermore, the present invention relates to a battery pack provided with the battery pack case. More specifically, when a fire occurs in a battery, the fire extinguishing liquid stored in the fire extinguishing liquid storage means is sprayed through the case cover located on the upper part of the battery pack so that a part or the whole of the battery is immersed, whereby the fire extinguishing liquid rapidly cools the battery cell or is absorbed into the inside of the battery cell to suppress the internal thermal runaway reaction and prevent the transfer to adjacent cells. The present invention relates to a battery pack.

Background Art

[0003] Recently, electric vehicles using batteries have been increasing rapidly. On the other hand, battery fires often occur, but the occurrence of fires due to sparks or leakage is in a situation that is almost unpredictable. Therefore, it is necessary to be prepared for fires.

[0004] The battery for an electric vehicle is in a form in which a large number of battery modules in which a large number of battery cells are connected are mounted. However, even if a fire occurs in one battery cell, the problem is that the fire rapidly spreads 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 power produced at a power plant and transmits power when power is temporarily insufficient. Recently, large-scale ESS devices are being configured in a smaller size and are increasingly used for power outage preparation or peak power reduction in general consumers such as buildings, factories, and homes.

[0006] Recently, interest in new and renewable energy sources has rapidly increased due to imbalances in electricity supply and demand, and development is continuously underway on technologies that store electricity produced using new and renewable energy sources via ESS (Energy Storage Systems) and utilize it when needed.

[0007] In particular, with the recent mandatory installation of Energy Storage Systems (ESS) in newly constructed public buildings, and the increasing installation of ESS in private buildings and other structures for energy conservation purposes, the ESS market continues to grow.

[0008] When installing an ESS (Energy Storage System) in a building, the ESS's battery rack (battery module) houses the battery for storing energy, the BMS (Battery Management System) for managing the battery, and the PCS (Power Conditioning System) for converting power. These battery racks are then housed and operated in a designated space, such as a basement.

[0009] Generally, secondary batteries can be recharged and reused, and in recent years, lithium-ion batteries, which have high charge and discharge efficiency, have become widely used. Because lithium-ion batteries have a relatively small volume and high charge and discharge efficiency, their use is increasing not only in electric vehicles and ESSs, but also in power plants, charging stations, and even portable devices.

[0010] However, lithium-ion batteries have a thin separator membrane between the negative electrode and the positive electrode. This separator membrane can be damaged by impact, or it can short-circuit between the cathode and positive electrode due to aging or the growth of dentites, potentially causing a fire. In the case of large-scale equipment, this can result in enormous financial losses.

[0011] On the other hand, while battery packs, including battery modules, employ air-cooling or water-cooling technologies to maintain proper cell temperatures, they cannot adequately control temperatures when thermal runaway occurs in battery cells. This can lead to a serious fire where thermal runaway transfers to adjacent cells, causing the entire battery to ignite.

[0012] Numerous prior art documents describe battery modules or packs equipped with separate fire extinguishing devices to suppress fires caused by thermal runaway in battery cells. However, due to spatial and structural constraints, these devices are limited in that they cannot contain enough extinguishing fluid to extinguish a fire in a battery cell. Furthermore, conventional prior art designs involve spraying a small amount of extinguishing fluid at a specific location, which is absolutely insufficient to extinguish a fire in an actual battery. Additionally, because the battery cells are in close contact with each other, the extinguishing fluid cannot adequately contact the battery cell where the fire has occurred, making it prone to spreading to adjacent cells. [Overview of the project] [Problems that the invention aims to solve]

[0013] Therefore, the present invention has been made to solve the problems of the prior art described above, and its purpose is to provide a battery pack case and a battery pack equipped therewith that have fire extinguishing and cooling functions, in which the case cover of the battery pack is configured to be integrated with a fire extinguishing plate, and when a specific cell or module experiences thermal runaway, a large amount of fire extinguishing liquid is concentratedly sprayed into the battery to effectively suppress the fire and prevent it from spreading to adjacent cells.

[0014] Another object of the present invention is to provide a battery pack that, in the event of a fire in the battery, sprays fire extinguishing liquid stored in a fire extinguishing liquid storage means via a case cover located at the top of the battery pack, so that part or all of the battery is submerged, thereby rapidly cooling the battery cells or being absorbed into the battery cells to suppress the internal thermal runaway reaction and prevent transfer to adjacent cells. [Means for solving the problem]

[0015] To achieve the above objective, the present invention provides a battery pack case capable of housing a large number of battery modules, comprising a case body with one side open, and a case cover that opens and closes the open side of the case body, wherein the case cover comprises an external means configured in the shape of a plate of a certain width, comprising one or more chambers sealed to have an internal space of a certain capacity, a fire extinguishing liquid filled in a certain amount at a certain ejection pressure, a large number of spray nozzles formed on the external means so as to communicate with the internal space of the chambers in a direction facing the large number of battery modules, and a low-melting-point alloy (fusible) that is filled and sealed inside each of the large number of spray nozzles, and melts at a certain temperature in the event of a fire in the battery, so as to spray the fire extinguishing liquid into the battery through the spray nozzle. The external means includes a number of sealing lids made of an alloy, and the external means includes an upper plate and a lower plate, each made of a metal material and formed along their edges, and welded together along their edges to form a certain internal space, the upper plate and the lower plate each having a number of formed portions that protrude inward so that when they are in close contact with each other their ends are in surface contact with each other and welded together between the upper and lower parts, the injection nozzle is integrally formed with the lower plate by forming a hole with a part of the lower plate further protruding outward, and the inner surface of the injection nozzle is threaded to further strengthen the bonding force between the sealing lid of the low melting point alloy and the inner surface of the injection nozzle.

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

[0017] Furthermore, the battery pack of the present invention for achieving the above objectives includes a number of battery modules and a case for housing the number of battery modules, wherein the case includes a case body capable of housing the number of battery modules inside and having one side open, and a case cover for opening and closing the open side of the case body, and the case cover is configured as described above.

[0018] The battery pack stores a fire extinguishing liquid at a constant discharge pressure, sufficient to immerse all or some of the numerous battery modules in the case, and may further include a fire extinguishing liquid storage means for supplying the liquid into the case in the event of a fire in the battery.

[0019] The case body preferably has a partition wall structure inside that is divided into a number of sections so that the number of battery modules can be housed in their respective isolated spaces, and it is even more preferable that the partition walls of the case body are configured to be lower than the edges of the case body.

[0020] The battery module may include a large number of stacked battery cells and a large number of porous absorbent pads arranged between the battery cells. Preferably, the fire extinguishing liquid storage means is in communication with one side of the outer shape means via a communication line, and the fire extinguishing liquid stored in the fire extinguishing liquid storage means is sprayed towards the battery where the fire has occurred via the outer shape means and through the open discharge port 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 created by filling their respective internal spaces with compressed air or nitrogen gas. [Effects of the Invention]

[0022] The present invention configures the case cover of the battery pack to be integrated with the fire extinguishing plate, and when thermal runaway occurs in a specific cell or module, a large amount of fire extinguishing liquid is intensively injected into the battery to effectively suppress the fire and prevent the transfer to adjacent cells.

[0023] Also, when a fire occurs in the battery, the present invention injects the fire extinguishing liquid stored in the fire extinguishing liquid storage means through the case cover located at the upper part of the battery pack so that part or all of the battery is immersed, and the fire extinguishing liquid quickly cools the battery cells or is absorbed into the interior of the battery cells to suppress the internal thermal runaway reaction and prevent the transfer to adjacent cells.

[0024] That is, the present invention first injects the fire extinguishing liquid stored in the case cover located at the upper part of the battery pack to the fire occurrence site to quickly extinguish the flame, and secondarily injects the fire extinguishing liquid stored in the fire extinguishing liquid storage means into the case so that part or all of the battery is immersed in the fire extinguishing liquid, so that the fire extinguishing liquid is absorbed into the interior of the battery cells to suppress the internal thermal runaway reaction and prevent the transfer to adjacent cells.

[0025] Specifically, in the present invention, when the temperature rises due to a fire in the battery, the temperature of the injection nozzle of the case cover at the part closest to the battery where the fire occurred rises, and the low-melting-point alloy that sealed the discharge port of the injection nozzle melts at a predetermined temperature, opening the discharge port of the injection nozzle. Through the opened discharge port, the fire extinguishing liquid stored in the internal space of the chamber of the case cover is primary-injected toward the battery where the fire occurred at a certain ejection pressure, enabling initial fire suppression for the battery where the fire occurred. Thereafter, the fire extinguishing liquid stored in the fire extinguishing liquid storage means is secondary-injected toward the battery where the fire occurred through the opened discharge port of the injection nozzle via the case cover, and by immersing part or all of the battery module where the fire occurred in the fire extinguishing liquid, the fire extinguishing liquid can be absorbed into the inside of the battery cell to suppress the internal thermal runaway reaction and prevent transfer to adjacent cells. Furthermore, when the fire extinguishing liquid overflows beyond the partition wall of the battery module where the fire occurred, it can also serve to fill the separation space of the adjacent battery module to prevent the propagation of flames and heat to adjacent cells.

Brief Description of the Drawings

[0026] [Figure 1] It is a schematic perspective view showing the configuration relationship of a battery pack provided with a battery pack case having a fire extinguishing function according to the first embodiment of the present invention. [Figure 2] It is a cross-sectional view showing the configuration relationship of a battery pack provided with a battery pack case having a fire extinguishing function according to the first embodiment of the present invention. [Figure 3] It is a cross-sectional view of the battery pack case having a fire extinguishing function shown in FIG. 1. [Figure 4] It is an enlarged cross-sectional view of part A shown in FIG. 3. [Figure 5] It is a schematic view showing the configuration relationship of a battery pack provided with a battery pack case having a fire extinguishing function according to the second embodiment of the present invention. [Figure 6] It is a schematic view showing the configuration relationship of the battery module shown in FIG. 5 and the circulation process of the fire extinguishing liquid. [Figure 7] Figure 5 is a perspective view showing the configuration of the case body. [Figure 8] Figure 7 is a plan view showing the battery module positioned within the partition wall of the case body. [Figure 9] Figure 5 is a cross-sectional view showing the structural relationship of the case cover. [Figure 10] This is an enlarged cross-sectional view of portion B shown in Figure 9. [Modes for carrying out the invention]

[0027] The fire-extinguishing battery pack case of the present invention is positioned in contact with or adjacent to a battery in an electric vehicle or ESS, and is used to suppress a fire in the event of a fire in the battery. Furthermore, the battery pack of the present invention is applicable to electric vehicles and ESS, and is configured to suppress a fire in the event of a fire in the battery.

[0028] Preferred embodiments of the battery pack case having a fire extinguishing function and the battery pack equipped therewith according to the present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to the embodiments disclosed below and can be realized in a variety of different forms. However, these embodiments are provided to complete the disclosure of the present invention and to fully inform those in the ordinary skill of the scope of the invention.

[0029] [First Embodiment] Figures 1 and 2 are schematic perspective and cross-sectional views showing the configuration of a battery pack with a fire-extinguishing battery pack case according to the first embodiment of the present invention, Figure 3 is a lateral cross-sectional view of the fire-extinguishing battery pack case shown in Figure 1, and Figure 4 is an enlarged cross-sectional view of portion A shown in Figure 3.

[0030] As shown in Figures 1 to 4, the battery pack according to this embodiment is composed of 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 can be arranged in large numbers inside the case 100. Here, the battery modules 10 can be arranged in large numbers of columns and rows inside the case 100. A single battery module 10 can also include a large number of stacked battery cells, and each battery cell can include a positive electrode plate, a negative electrode plate, and a separator interposed between the positive and negative electrode plates. The battery module 10 can also include a protection circuit module provided in each battery cell, or a protection circuit module integrally connected to a large number of battery cells, and the protection circuit module can control the voltage or current during charging and discharging of the battery cells. Furthermore, electrode tabs can be pulled out in each battery cell, and the electrode assembly can include all known forms such as stacked or wound types.

[0032] The case 100 is a component that houses a number of battery modules 10 inside, and may include a case body 120 and a case cover 110. Here, the case body 120 can house a number of battery modules 10 inside and can take the form of a box 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 relative to 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 suppressing fires caused by thermal runaway. Specifically, the case cover 110 is configured to have an integrated fire suppression plate and is configured to effectively suppress the fire by injecting a large amount of fire suppression liquid into the battery when thermal runaway occurs in a particular cell or module, thereby preventing the fire from spreading to adjacent cells.

[0034] Such a case cover 110 is designed to extinguish a fire in a battery (specific cell or module) by spraying a built-in fire-extinguishing liquid at the fire site. It comprises an external shape means 111 which is a plate-shaped structure of a certain width with a sealed chamber having a certain internal volume; a certain amount of fire-extinguishing liquid (not shown) filled into the chamber's internal space at a certain ejection pressure; a number of spray nozzles 116 formed on the external shape means 111 so as to communicate with the chamber's internal space in directions facing a number of battery modules 10; and a number of sealed lids 117 which are filled inside the number of spray nozzles 116 and sealed, and which are made of a fusible alloy that melts when heated above a certain temperature during a thermal runaway of the battery, allowing the fire-extinguishing liquid to be sprayed into the battery via the spray nozzles 116.

[0035] The external shaping means 111 serves as a frame that constitutes the appearance of the case cover 110, and consists 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. The upper plate 112 and the lower plate 114 in this embodiment are made of a metal material such as stainless steel or aluminum, but it is preferable that their thickness is between 0.2 and 1.0 mm considering rigidity and weight reduction. On the other hand, the overall thickness of the case cover 110 is preferably between 3 and 10 mm considering the capacity of the fire extinguishing liquid, the vehicle structure and weight.

[0036] On the other hand, as shown in Figure 3, the upper plate 112 and the lower plate 114 are configured to have a number of formed portions 113 and 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 formed portions 113 and 115, and when they are brought into close contact with each other, the ends of the formed portions 113 and 115 make surface contact with each other. The edges of the upper plate 112 and the lower plate 114, which are press-formed into an embossed shape, and the formed portions 113 and 115 are welded to each other to ensure rigidity that prevents expansion deformation due to the high-pressure fire extinguishing liquid inside, and to seal the fire extinguishing liquid so as not to leak.

[0037] As shown in Figure 4, the lower plate 114 faces the inside of the battery pack, i.e., a number of battery modules 10, and is equipped with a number of heat-sensitive spray nozzles 116. When a battery fire occurs, the internal temperature of the battery module or pack rises, automatically spraying fire extinguishing liquid through the spray nozzles 116. In this heat-sensitive system, the spray nozzles 116 are formed on the lower plate 114 and have a sealed lid 117 sealed with a low-melting-point alloy (fusible alloy) that melts at a low temperature (60-150°C). When the internal temperature of the battery pack reaches a predetermined temperature, the low-melting-point alloy melts, the spray nozzle opens, and high-pressure fire extinguishing liquid is sprayed through the outlet of the spray nozzle 116. The low-melting-point alloy in this embodiment can be composed of a mixture of components such as bismuth, lead, tin, indium, cadmium, and gallium.

[0038] On the other hand, the injection nozzle 116 is formed integrally with the lower plate 114 by creating a hole in the lower plate 114 while a portion of the lower plate 114 is further protruding outward through a burring process during press forming of the lower plate 114 into an embossed shape. In other words, the injection nozzle 116 of this embodiment has the effect of reducing manufacturing costs and thickness by being integrally constructed with the lower plate 114 without attaching a separate plug for nozzle manufacturing. In this case, the inner diameter of the injection nozzle 116 is preferably 2 to 5 mm, and the height is preferably 2 to 5 mm, taking into consideration sealing rigidity and injection speed.

[0039] In this embodiment, the case cover 110 has a configuration in which a certain amount of fire extinguishing liquid fills the internal space of the chamber at a constant ejection pressure. Therefore, even if the low-melting-point alloy constituting the sealing cover 117 does not melt due to external heat such as a fire, the sealing lid 117 that sealed the outlet of the spray nozzle 116 must not detach from the outlet due to the ejection pressure of the fire extinguishing liquid. However, as can be seen from Figure 4, in this embodiment, the upper part of the spray nozzle 116 has a curved tapered shape during the burring process, so there is no risk of the sealing lid 117 that sealed the outlet of the spray nozzle 116 detaching from the outlet due to the ejection pressure of the fire extinguishing liquid. However, as shown in Figure 4(b), it is even more preferable to machine a thread tap on the inner surface of the spray nozzle 116 to further strengthen the bonding force between the low-melting-point alloy sealing lid 117 and the inner surface of the spray nozzle 116, so that it can withstand even higher ejection pressures of the fire extinguishing liquid.

[0040] Furthermore, the lower plate 114 may also be configured by attaching a separate insulating coating layer or insulating pad for insulation from terminals such as busbars inside the battery pack.

[0041] On the other hand, the internal space of the chamber in this embodiment is filled with a certain amount of fire extinguishing liquid so as to have a constant ejection pressure. In this case, to incorporate the fire extinguishing liquid so as to have a constant ejection pressure, the internal space of the chamber can be filled with compressed air or nitrogen gas. That is, a communication port (not shown) that communicates 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 into the internal space of the chamber through this communication port. After filling the internal space of the chamber with a certain amount of fire extinguishing liquid using the vacuum pressure, compressed air or nitrogen gas is then filled in, so that the internal space of the chamber is filled with fire extinguishing liquid at a constant ejection pressure. Therefore, when the discharge port of the spray nozzle 116 is opened, the fire extinguishing liquid is sprayed toward the battery by its own ejection pressure. On the other hand, the fire extinguishing liquid is an agent that extinguishes fire by reacting with the flame and evaporating, and its ejection pressure (internal pressure) is 5 to 10 kgf / cm². 2 It is preferable to incorporate it into the internal space of the chamber so that it has a pressure of (0.490~0.981 MPa).

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

[0043] In this embodiment, the external means 111 is composed of a single chamber, but it can also be composed of a number of chambers, each having an internal space that is sealed off from the others. In this case, the number of chambers can be varied depending on the application environment.

[0044] The case cover 110 of this embodiment, configured as described above, enables initial suppression of a fire in the battery. Specifically, when the temperature rises due to a fire in the battery, the temperature of the injection nozzle 116 closest to the burning battery rises, causing the low-melting-point alloy sealing the outlet of the injection nozzle 116 to melt at a predetermined temperature, opening the outlet of the injection nozzle 116. Through this opened outlet, the fire extinguishing liquid contained within the chamber is sprayed towards the burning battery at a constant ejection pressure, thus enabling initial fire suppression of the burning battery.

[0045] On the other hand, 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. Furthermore, the case cover 110 of this embodiment can also be configured to be used in conjunction with a separate tank storing fire extinguishing liquid, thereby enabling more efficient fire suppression by spraying the fire extinguishing liquid stored inside the chamber and in the tank onto the fire site.

[0046] The case cover 110 of this embodiment, configured in this way, is positioned in contact with or adjacent to a battery in an electric vehicle or ESS, and can be used to suppress a fire in the event of a fire in the battery.

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

[0048] As shown in Figures 5 to 10, the battery pack with a fire-extinguishing function according to the second embodiment of the present invention comprises a number of battery modules 10, a case 200 that houses the number of battery modules 10 in their respective separate spaces, and a fire-extinguishing liquid storage means 300 that stores a fire-extinguishing liquid at a constant ejection pressure and supplies it into the case 200, in an amount sufficient to immerse all or some of the battery modules 10 in the case 200.

[0049] The battery module 10 is a component that generates electrochemical energy through the movement of ions or electrons, and can be arranged in large numbers inside the case 200. Here, the battery modules 10 can be arranged in large numbers of columns and rows inside the case 200 (see Figure 8). Also, as shown in Figure 6, one battery module 10 can include a large number of stacked battery cells 11, and each battery cell 11 can include a positive electrode plate, a negative electrode plate, and a separator interposed between the positive and negative electrode plates. The battery module 10 can also include a protection circuit module provided in each battery cell 11, or a protection circuit module integrally connected to a large number of battery cells, and the protection circuit module can control the voltage or current during charging and discharging of the battery cells 11. In addition, electrode tabs can be pulled out in each battery cell 11, and the electrode assembly can include all known forms such as stacked or wound types.

[0050] Furthermore, as shown in Figure 6, the battery module 10 may include a number of porous absorbent pads 12 that are placed between a number of battery cells 11. The porous absorbent pads 12 are preferably made of a non-combustible material that has capillary force capable of absorbing fire extinguishing liquid even when both sides are in close contact with the battery cells 11. Such non-combustible materials can be inorganic fibrous materials such as glass wool or ceramic wool, or granular inorganic materials such as silica or activated carbon, or a mixture of inorganic materials and heat-resistant silicon can be applied. By providing such porous absorbent pads 12 between the battery cells 11, it is possible to cool the battery and extinguish the fire more efficiently than when a fire occurs, and it is also possible to prevent the spread of flames and heat to adjacent cells.

[0051] The case 200 is a component that houses a number of battery modules 10 in their respective isolation spaces, and may include a case body 220 and a case cover 210. Here, the case body 220 is a box shape that can house a number of battery modules 10 inside and has an open side, and is configured to have a partition wall structure inside that is divided into a number of areas so that a number of battery modules 10 can be housed in their respective isolation spaces (see Figures 7 and 8). Therefore, the fire extinguishing liquid will fill only the isolation space of the battery module 10 that has ignited, and will be able to immerse it up to the height of all or part of the battery module 10 there (see Figure 5). On the other hand, the partition wall 221 of the case body 220 may be configured to be lower than the edge of the case body 220, in which case the fire extinguishing liquid will initially fill the isolation space of the ignited battery module 10 to extinguish the fire, and if it overflows beyond the partition wall 221, it can also fill the isolation space of the adjacent battery module 10, playing a role in preventing the spread of flames and heat to adjacent cells.

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

[0053] Furthermore, the case cover 210 is configured to simultaneously have the function of sealing the inside of the case body 220 and a fire extinguishing function to suppress fires caused by thermal runaway. Specifically, the case cover 210 is configured to have an integrated fire extinguishing plate and is configured to effectively suppress the fire by intensively spraying a large amount of fire extinguishing liquid into the battery when thermal runaway occurs in a particular cell or module, thereby preventing the fire from spreading to adjacent cells.

[0054] Such a case cover 210 is designed to extinguish a fire in a battery (specific cell or module) by spraying a built-in fire-extinguishing liquid at the fire site. It comprises an external shape means 211 which is a plate-shaped structure of a certain width with a sealed chamber having a certain internal volume; a certain amount of fire-extinguishing liquid that fills the internal space of the chamber with a certain amount at a certain ejection pressure; a number of spray nozzles 216 formed on the external shape means 211 so as to communicate with the internal space of the chamber in directions toward a number of battery modules 10; and a number of sealing lids 217 which fill and seal the inside of the number of spray nozzles 216 and are made of a fusible alloy that melts when heated above a certain temperature during thermal runaway of the battery, allowing the fire-extinguishing liquid to be sprayed onto the battery via the spray nozzles 216.

[0055] The external shaping means 211 serves as a frame that constitutes the appearance of the case cover 210, and consists 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. The upper plate 212 and the lower plate 214 in this embodiment are made of a metal material such as stainless steel or aluminum, but it is preferable that their thickness is between 0.2 and 1.0 mm considering rigidity and weight reduction. On the other hand, the total thickness of the case cover 210 is preferably between 3 and 10 mm considering the capacity of the fire extinguishing liquid, the vehicle structure and weight.

[0056] On the other hand, as shown in Figure 9, the upper plate 212 and the lower plate 214 are configured to have a number of formed portions 213 and 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 formed portions 213 and 215, and when they are brought into close contact with each other, the ends of the formed portions 213 and 215 make surface contact with each other. The edges of the upper plate 212 and the lower plate 214, which are press-formed into an embossed shape, and the formed portions 213 and 215 are welded to each other to ensure rigidity that prevents expansion deformation due to the high-pressure fire extinguishing liquid inside, and to seal the fire extinguishing liquid so as not to leak.

[0057] As shown in Figure 10, the lower plate 214 faces the inside of the battery pack, i.e., a number of battery modules 10, and is equipped with a number of heat-sensitive spray nozzles 216. When a battery fire occurs, the internal temperature of the battery module or pack rises, automatically spraying fire extinguishing liquid through the spray nozzles 216. In this heat-sensitive system, the spray nozzles 216 are formed on the lower plate 214 and have a sealed lid 217 sealed with a low-melting-point alloy (fusible alloy) that melts at a low temperature (60-150°C). When the internal temperature of the battery pack reaches a predetermined temperature, the low-melting-point alloy melts, opening the spray nozzles 216 and spraying high-pressure fire extinguishing liquid through the outlets of the spray nozzles 216. The low-melting-point alloy in this embodiment can be composed of a mixture of components such as bismuth, lead, tin, indium, cadmium, and gallium.

[0058] On the other hand, the injection nozzle 216 is formed integrally with the lower plate 214 by forming a hole in the lower plate 214 through a burring process during press forming to create an embossed shape, causing a portion of the lower plate 214 to protrude further outward. In other words, the injection nozzle 216 in this embodiment is integrally constructed with the lower plate 214 without the need to attach a separate plug for nozzle manufacturing, thereby reducing manufacturing costs and thickness. In this case, the inner diameter of the injection nozzle 216 is preferably 2 to 5 mm, and the height is preferably 2 to 5 mm, taking into consideration sealing rigidity and injection speed.

[0059] In this embodiment, the case cover 210 has a configuration in which a certain amount of fire extinguishing liquid fills the internal space of the chamber at a constant ejection pressure. Therefore, even though the low-melting-point alloy constituting the sealing cover 217 has not melted due to external heat such as a fire, the sealing cover 217 that sealed the outlet of the spray nozzle 216 must not detach from the outlet due to the ejection pressure of the fire extinguishing liquid. However, as can be seen from Figure 10, in this embodiment, the upper part of the spray nozzle 216 has a curved tapered shape during the burring process, so there is no risk of the sealing cover 217 that sealed the outlet of the spray nozzle 216 detaching from the outlet due to the ejection pressure of the fire extinguishing liquid. However, it is even more preferable to configure the nozzle to withstand higher ejection pressures of the fire extinguishing liquid by further strengthening the bonding force between the low-melting-point alloy sealing cover 217 and the inner surface of the spray nozzle 216 by machining a thread tap on the inner surface of the spray nozzle 216, as shown in Figure 10(b).

[0060] Furthermore, the lower plate 214 may be configured with an additional insulating coating layer or insulating pad to provide insulation from terminals such as busbars inside the battery pack. On the other hand, the internal space of the chamber in this embodiment is filled with a certain amount of fire extinguishing liquid so as to have a constant ejection pressure. In this case, to incorporate the fire extinguishing liquid so as to have a constant ejection pressure, the internal space of the chamber can be filled with compressed air or nitrogen gas. That is, a communication port (not shown) that communicates with the internal space of the chamber is formed, for example, at one location on one side of the upper plate 212, and a vacuum is drawn into the internal space of the chamber through this communication port. After filling the internal space of the chamber with a certain amount of fire extinguishing liquid using the vacuum pressure, compressed air or nitrogen gas is then added to fill the internal space of the chamber, so that the fire extinguishing liquid fills the internal space of the chamber with a constant ejection pressure. Therefore, when the discharge port of the spray nozzle 216 is opened, the fire extinguishing liquid is sprayed towards the battery by its own ejection pressure. On the other hand, the fire extinguishing liquid is an agent that extinguishes fire by reacting with the flame and evaporating, and its ejection pressure (internal pressure) is 5 to 10 kgf / cm². 2 It is preferable to incorporate it into the internal space of the chamber so that it has a pressure of (0.490~0.981 MPa).

[0061] The fire extinguishing liquid is preferably an agent that has the property of evaporating easily even at low temperatures due to its latent heat of vaporization cooling effect, and in order to prevent short circuits between the battery terminals and busbars when the fire extinguishing liquid is sprayed, a fluorinated ketone (C6F) that also possesses insulating properties is preferable. 12 It is even more preferable to use 0) or a fluorine-based ketone (FK-5-1-1, dodecafluoro-2-methylpentane-3-one), etc.

[0062] In this embodiment, the external means 211 is composed of a single chamber, but it may be composed of a number of chambers, each having an internal space that is sealed off from the others. In this case, the number of chambers can be varied depending on the application environment. On the other hand, the case cover 210 of this embodiment may be further configured to have a pressure gauge (not shown) for measuring the pressure inside the chamber.

[0063] As shown in Figure 5, the fire extinguishing liquid storage means 300 stores a certain volume of fire extinguishing liquid at a certain discharge pressure and supplies it into the case 200 in the event of a fire in the battery, and communicates with one side of the outer shape means 211 of the case cover 210 via a communication line.

[0064] Furthermore, the fire extinguishing liquid storage means 300 has a structure in which a certain amount of fire extinguishing liquid is filled into its tank so that it has the same constant ejection pressure as the inside of the case cover 210. In this case, the fire extinguishing liquid is stored in such a way as to have a constant ejection pressure, and the internal space of the tank can be filled with compressed air or nitrogen gas. The fire extinguishing liquid in the fire extinguishing liquid storage means 300 is a fluorinated ketone (C6F) which has the same insulating properties as the fire extinguishing liquid in the case cover 210. 12 0) or fluorine-based ketones (FK-5-1-12, dodecafluoro-2-methylpentane-3-one) can be used. Such a fire extinguishing liquid storage means 300 plays a role in more reliably suppressing a fire by spraying the stored fire extinguishing liquid onto the fire site via the case cover 210 when a fire occurs in the battery (a specific cell or module).

[0065] The battery pack of this embodiment is configured to first spray the fire extinguishing liquid stored in the case cover 210 onto the fire site to quickly extinguish the flames, and secondarily spray the fire extinguishing liquid stored in the fire extinguishing liquid storage means 300 onto the fire site via the case cover 210 so that part or all of the battery is immersed in the fire extinguishing liquid, thereby absorbing the fire extinguishing liquid into the inside of the battery cells 11 to suppress the internal thermal runaway reaction and prevent it from transferring to adjacent cells. On the other hand, 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, so that when a fire occurs in the battery, the vent valve opens and the fire extinguishing liquid can be smoothly sprayed without being affected by the internal pressure of the case 200.

[0066] As described above, the battery pack of this embodiment not only enables initial suppression of a fire in the battery, but also suppresses thermal runaway reactions and prevents transfer to adjacent cells. Specifically, when the temperature rises due to a fire in the battery, 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 that was sealing the outlet of the spray nozzle 216 melts at a predetermined temperature, opening the outlet of the spray nozzle 216. Through this opened outlet, the fire extinguishing liquid contained in the internal space of the chamber of the case cover 210 is temporarily sprayed toward the battery where the fire occurred at a constant ejection pressure, thus enabling initial fire suppression of the battery where the fire occurred. Subsequently, the fire extinguishing liquid stored in the fire extinguishing liquid storage means 300 is secondarily sprayed towards the battery where the fire occurred via the case cover 210 and the open discharge port of the spray nozzle 216, so that part or all of the battery module 10 where the fire occurred is immersed in the fire extinguishing liquid, so that the fire extinguishing liquid is absorbed into the inside of the battery cell 11, suppressing the internal thermal runaway reaction and preventing it from transferring to adjacent cells. Furthermore, if the fire extinguishing liquid overflows beyond the partition wall 221 of the battery module 10 where the fire occurred, it can also fill the separation space of the adjacent battery module 10, preventing the propagation of flames and heat to adjacent cells.

[0067] The technical details relating to the battery pack case having a fire extinguishing function and the battery pack equipped therewith of the present invention have been described above with reference to the accompanying drawings. This is an illustrative description of the most preferred embodiment of the present invention. Therefore, the present invention is not limited to the above embodiment, and it is obvious to those with ordinary skill in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Thus, such modifications or variations should also be considered to fall within the scope of the claims of the present invention. [Industrial applicability]

[0068] This invention can be applied to electric vehicles and ESS (Energy Storage Systems), and can be used to suppress fires that occur in batteries.

Claims

1. A battery pack case that can house a number of battery modules inside, and includes a case body with one side open, and a case cover that opens and closes the open side of the case body, The case cover includes an upper plate and a lower plate that are arranged to face each other, The upper plate and the lower plate are joined together along their edges, thereby forming one or more sealed chambers between the upper plate and the lower plate that have an internal space of a predetermined volume. The upper plate and the lower plate each have a number of forming portions formed on their respective inner surfaces and arranged to correspond to each other. The numerous forming portions are formed to protrude in a direction that brings the upper plate and the lower plate into close contact with each other. The ends of the forming portions of the upper plate and the lower plate are formed to be in surface contact with each other and are welded together in that surface contact state. The internal space of one or more of the aforementioned chambers is filled with a certain amount of fire extinguishing liquid at a constant ejection pressure. The lower plate has a number of injection nozzles formed in a direction toward the number of battery modules. The numerous injection nozzles are integrally formed with the lower plate by forming a part of the lower plate that protrudes outward and then forming through holes. The numerous injection nozzles are formed to penetrate the lower plate and open directly into the internal space of one or more chambers. Each of the one or more chambers is arranged to have the number of injection nozzles, and each injection nozzle is configured to communicate directly with the internal space of the corresponding chamber. The aforementioned number of injection nozzles are sealed by a sealing lid made of a low-melting-point alloy, and are configured to be released when the sealing lid melts above a set temperature. A battery pack case characterized by machining a thread tap on the inner surface of the injection nozzle to further strengthen the bonding force between the low-melting-point alloy sealing lid 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 insulating pad for insulating from the terminals inside the battery pack.

3. The battery pack case according to claim 1, characterized in that the constant ejection pressure of the fire extinguishing liquid is formed by filling the internal space of the chamber with compressed air or nitrogen gas.

4. A battery pack comprising a number of battery modules and a case for housing the number of battery modules, The case can accommodate the numerous battery modules inside and includes a case body with one side open and a case cover that opens and closes the open side of the case body. The case cover includes an upper plate and a lower plate that are arranged to face each other, The upper plate and the lower plate are joined together along their edges, thereby forming one or more sealed chambers between the upper plate and the lower plate that have an internal space of a predetermined volume. The upper plate and the lower plate each have a number of forming portions formed on their respective inner surfaces and arranged to correspond to each other. The numerous forming portions are formed to protrude in a direction that brings the upper plate and the lower plate into close contact with each other. The ends of the forming portions of the upper plate and the lower plate are formed to be in surface contact with each other and are welded together in that surface contact state. The internal space of one or more of the aforementioned chambers is filled with a certain amount of fire extinguishing liquid at a constant ejection pressure. The lower plate has a number of injection nozzles formed in a direction toward the number of battery modules. The numerous injection nozzles are integrally formed with the lower plate by forming a part of the lower plate that protrudes outward and then forming through holes. The numerous injection nozzles are formed to penetrate the lower plate and open directly into the internal space of one or more chambers. Each of the one or more chambers is arranged to have the number of injection nozzles, and each injection nozzle is configured to communicate directly with the internal space of the corresponding chamber. The aforementioned number of injection nozzles are sealed by a sealing lid made of a low-melting-point alloy, and are configured to be released when the sealing lid melts above a set temperature. A battery pack characterized by further strengthening the bonding force between the low-melting-point alloy sealing lid and the inner surface of the injection nozzle by machining a thread tap on the inner surface of the injection nozzle.

5. The battery pack according to claim 4, further comprising a means for storing fire extinguishing liquid at a constant spray pressure, sufficient to immerse all or some of the numerous battery modules in the case, and for supplying fire extinguishing liquid into the case in the event of a fire in the battery.

6. The battery pack according to claim 5, characterized in that the case body has a partition structure inside which it is divided into a number of areas so that the number of battery modules can each be housed in their respective separate spaces.

7. The battery pack according to claim 6, characterized in that the partition wall of the case body is configured to be lower in height than the edge of the case body.

8. The battery pack according to claim 5, characterized in that the battery module includes a large number of stacked battery cells and a large number of porous absorbent pads arranged between the large number of battery cells.

9. The battery pack according to claim 5, characterized in that the fire extinguishing liquid storage means is in communication with one side of the case cover via a communication line, and the fire extinguishing liquid stored in the fire extinguishing liquid storage means is sprayed towards the battery where the fire has occurred via the case cover and through the open outlet of the spray nozzle.

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

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