Fire extinguishing system for plurality of battery cells

Abstract

A fire extinguishing system for a plurality of battery cells includes: a fire extinguishing conduit defining an injection hole for injecting a fire extinguishing agent to a vent hole in one of the plurality of battery cells; and a heat-sensitive member blocking the injection hole, and including a main body portion at least partially surrounding an outer periphery of the fire extinguishing duct, and a nozzle portion corresponding to the injection hole and having a thickness smaller than a thickness of the main body portion.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0008739, filed on January 19, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] Various aspects of embodiments of this disclosure relate to fire suppression systems for multiple battery cells. Background Technology

[0004] Unlike primary batteries, which are not designed for (re)charging, secondary (or rechargeable) batteries are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for driving motors in hybrid and electric vehicles, as well as for storing electricity (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly consisting of positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0005] The information disclosed in this background section is intended to enhance the understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Utility Model Content

[0006] According to one or more embodiments of the present disclosure, a battery pack fire suppression system is provided, which is configured to spray a fire extinguishing agent onto the corresponding battery cell even when a low-temperature event occurs in the battery cell of the battery pack, thereby reducing the temperature of the corresponding battery cell and the temperature of nearby battery cells to reduce or prevent the possibility of heat propagation to another battery cell adjacent to the corresponding battery cell.

[0007] These and other aspects and features of this disclosure will be described in the following description of embodiments of this disclosure, or will become apparent from the following description of embodiments of this disclosure.

[0008] A fire extinguishing system for multiple battery cells according to one or more embodiments of the present disclosure includes: a fire extinguishing conduit defining a spray orifice for spraying a fire extinguishing agent into an vent hole in one of the multiple battery cells; and a heat-sensitive member blocking the spray orifice and including a body portion and a nozzle portion, the body portion at least partially surrounding the outer periphery of the fire extinguishing conduit, the nozzle portion corresponding to the spray orifice and having a thickness less than that of the body portion.

[0009] The nozzle portion can include a recessed portion in the body portion and recessed toward the ejection hole, and a thin film portion at a bottom of the recessed portion and having a thickness less than the thickness of the body portion.

[0010] The nozzle portion can further include an extended recessed portion outside the recessed portion, having a diameter greater than a diameter of the recessed portion, having a thickness less than the thickness of the body portion, and having a thickness greater than the thickness of the thin film portion.

[0011] A diameter of the recessed portion can be less than a diameter of the ejection hole.

[0012] A diameter of the ejection hole can be about 6% to about 30% of a cross-sectional arc length of the fire extinguishing conduit.

[0013] The recessed portion can include an inner wall having a thickness greater than the thickness of the thin film portion.

[0014] The recessed portion can include an inner wall having a thickness about 1.5 times to about 3 times the thickness of the thin film portion.

[0015] The recessed portion can include an inner wall having a thickness about 0.15 mm to about 1.5 mm.

[0016] The thickness of the thin film portion can be about 0.1 mm to about 0.5 mm.

[0017] A diameter of the ejection hole can correspond to an angle about 30° to about 90° around a center of the fire extinguishing conduit.

[0018] The recessed portion can include an inner wall having a height about 0.5 mm to about 3 mm.

[0019] The thin film portion can be configured to melt at a temperature about 150 °C to about 500 °C.

[0020] The thin film portion can be configured to melt by exhaust gas discharged from the exhaust hole in the one of the plurality of battery cells.

[0021] The fire extinguishing system can further include a temperature sensor configured to detect a temperature of the one of the plurality of battery cells, a smoke sensor configured to detect an amount of smoke from the one of the plurality of battery cells, a controller configured to receive temperature information about the one of the plurality of battery cells from the temperature sensor or smoke information about the one of the plurality of battery cells from the smoke sensor, and a valve between the fire extinguishing conduit and a fire extinguishing agent injection container and configured to be opened or closed in response to a control signal from the controller, the controller being configured to open the valve upon determining that the temperature exceeds a reference value or the amount of smoke exceeds a reference value.

[0022] The fire extinguishing conduit can be made of aluminum, copper, or stainless steel, wherein the heat-sensitive member is made of acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), or perfluoroalkoxy alkane (PFA).

[0023] However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the detailed description set forth below. BRIEF DESCRIPTION OF DRAWINGS

[0024] The following accompanying drawings, attached to the specification, illustrate embodiments of the present disclosure and together with the detailed description given below further describe the aspects and features of the present disclosure. Accordingly, the present disclosure should not be construed as being limited to the drawings:

[0025] FIG. 1A and FIG. 1B show a perspective view and a cross-sectional view of a battery cell, respectively;

[0026] FIG. 2 show a perspective view showing a battery module;

[0027] FIG. 3A and FIG. 3B show a perspective view showing a battery pack;

[0028] FIG. 4A and FIG. 4B show a perspective view and a side view of a vehicle body and a vehicle, respectively;

[0029] FIG. 5A to FIG. 5D show a schematic diagram illustrating a charging method for a secondary battery;

[0030] FIG. 6 is a schematic diagram showing a direct injection type battery pack fire extinguishing system according to the present disclosure;

[0031] FIG. 7FIG. 1 is a perspective view showing a direct-injection battery pack fire extinguishing system according to the present disclosure;

[0032] FIG. 8A FIG. 8B FIG. 6 is a graph showing the operation of the direct-injection battery pack fire extinguishing system according to the present disclosure;

[0033] FIG. 9A FIG. 9B FIG. 9C FIGS. 5A and 5B are plan and sectional views, respectively, showing a fire extinguishing guide pipe and a heat-sensitive member in the direct-injection battery pack fire extinguishing system according to the present disclosure; and

[0034] FIG. 10 FIG. 7 is a block diagram showing an electrical configuration of the direct-injection battery pack fire extinguishing system according to the present disclosure. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in the present specification and claims should not be interpreted as being limited to commonly used meanings or dictionary meanings, and should be interpreted based on the concept of a term in considering the technical spirit of the present disclosure on the basis of a principle that an inventor can properly define the concept of the term for the purpose of best describing his / her own application.

[0036] The embodiments described in the present specification and the configurations shown in the accompanying drawings are only some of the embodiments of the present disclosure, and do not represent all technical spirits, aspects, and features of the present disclosure. Accordingly, it should be understood that, at the time of filing the present application, various equivalents and modifications that can substitute or modify the embodiments described herein can exist.

[0037] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to" or "coupled to" another element or layer, it can be directly on the other element or layer, directly connected to or coupled to the other element or layer, or one or more intervening elements or layers can also be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being "coupled" or "connected" to a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0038] ​​​In the figures, the size of various elements, layers, etc., can be exaggerated for clarity. Like reference numbers signify like elements in all figures. As used in herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. In addition, usage of “can,” “may,” “might,” “could,” “would,” “should,” “might,” “will,” and the like, throughout this disclosure, are used to convey that the described event or circumstance can or might occur or events or circumstances can or might occur. Expressions such as “at least one of,” when preceding a list of two or more items, cover all of the individual items in the list, as well as any combination of the individual items in the list. The phrase, such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one of the group of A, B, and C,” or “at least one of A, B, and C when used herein to indicate a list of elements A, B, and C, the phrase can refer to only A, to only B, to only C, to any two of A, B, and C, or to any three of A, B, and C, as appropriate, and all combinations thereof. As used herein, the term “use” can be considered synonymous with the term “utilize.” As used herein, the terms “substantially,” “approximately,” and like terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measurements or calculations that would be recognized by those of ordinary skill in the art.

[0039] It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

[0040] Spatially relative terms (such as “beneath,” “below,” “lower,” “above,” “upper,” and the like) can be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0041] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0042] Further, any numerical ranges expressed in the disclosure and / or claims as endpoints include all the sub-ranges falling within the aforementioned ranges. For instance, a range of 1.0 to 10.0 should be considered to include any and all sub-ranges between (and including) the minimum value of 1.0 and the maximum value of 10.0; that is, all sub-ranges beginning with a minimum value of 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 2.4 to 7.6. Any maximum numerical limitation

[0043] Referring to two compared elements, features, etc., as "the same" can mean that they are "substantially the same." Thus, the phrase "substantially the same" can include cases where there is a deviation considered to be low in the art, e.g., a deviation of 5% or less. Additionally, when a certain parameter is said to be uniform in a given region, it can mean that it is uniform in terms of average value.

[0044] Throughout the specification, unless otherwise indicated, each element can be singular or plural.

[0045] Arranging an arbitrary element "above (or below)" or "on (or under)" another element can mean that the arbitrary element can be positioned in contact with the upper surface (or lower surface) of the element, and another element can also be interposed between the element and the arbitrary element located on (or under) the element.

[0046] In addition, it will be understood that when a component is referred to as being "linked", "coupled", or "connected" to another component, the components can be directly linked, coupled, or connected to each other, or other components can be "interposed" between the components.

[0047] Throughout the specification, unless otherwise indicated, when stating "A and / or B", it means A, B, or A and B. That is, "and / or" includes any one or all combinations of the listed items. Unless otherwise stated, when stating "C~D", it means C or above and D or below.

[0048] A battery pack according to one or more embodiments includes at least one battery module and a pack case having an accommodation space in which the at least one battery module is accommodated.

[0049] The battery module can include a plurality of battery cells and a module case. The battery cells can be accommodated inside the module case in a stacked form (or stacked arrangement or configuration). Each battery cell can have a positive electrode terminal and a negative electrode terminal, and can be round, prismatic, or pouch type according to the shape of the battery. In the present specification, the battery cell can also be referred to as a secondary battery, a battery, or a cell.

[0050] In the battery pack, one cell stack can constitute one module in place of a battery module stack. The cell stack can be accommodated in the accommodation space of the pack case, or can be accommodated in an accommodation space partitioned by a frame, a partition wall, or the like.

[0051] The battery cell can generate a large amount of heat during charging / discharging. The generated heat can accumulate in the battery cell, thereby accelerating deterioration of the battery cell. The battery pack can further include a cooling member to remove the generated heat, thereby suppressing deterioration of the battery cell. The cooling member can be provided at a bottom of the accommodation space in which the battery cell is provided, but is not limited thereto, and can be provided at a top or a side depending on the battery pack.

[0052] The battery cell can be configured such that exhaust gas generated inside the battery cell under an abnormal operating condition (also referred to as thermal runaway or thermal event) is discharged to the outside of the battery cell. The battery pack or the battery module can include an exhaust port for discharging the exhaust gas to prevent or reduce damage of the battery pack or the battery module by the exhaust gas.

[0053] The battery pack can include a battery and a battery management system (BMS) for managing the battery. The battery management system can include a detection device, an equalization device, and a control device. The battery module can include a plurality of cells connected in series and / or in parallel to each other. The battery modules can be connected in series and / or in parallel to each other.

[0054] The detection device can detect a state (e.g., voltage, current, temperature, etc.) of the battery to output state information indicating the state of the battery. The detection device can detect a voltage of each cell constituting a battery module or a voltage of each battery module. The detection device can detect a current flowing through each battery cell or battery module constituting a battery module. The detection device can also detect a temperature of a cell and / or a module at at least one point of the battery and / or an ambient temperature.

[0055] The equalization device can perform an equalization operation of the battery module and / or the cell constituting the battery module. The control device can receive state information (e.g., voltage, current, temperature, etc.) of the battery module from the detection device. The control device can monitor and calculate a state (e.g., voltage, current, temperature, state of charge (SOC), life (state of health (SOH), etc.) of the battery module based on the state information received from the detection device. Based on the monitored state information, the control device can perform a control function (e.g., temperature control, equalization control, charge / discharge control, etc.) and a protection function (e.g., over-discharge, over-charge, over-current protection, short circuit, fire extinguishing function, etc.). The control device can perform a wired or wireless communication function with an external device (e.g., a higher-level controller or a vehicle, a charger, a power conversion system, etc.) of the battery module.

[0056] The control device can control a charge / discharge operation and a protection operation of the battery. To this end, the control device can include a charge / discharge control unit, an equalization control unit, and / or a protection unit.

[0057] The battery management system is a system that monitors a state of the battery and performs a diagnosis as well as a control, communication, and protection function, and can calculate a charge / discharge state, calculate a battery life or state of health (SOH), cut off a power supply of the battery (e.g., relay control) if necessary, control thermal management (e.g., cooling, heating, etc.), perform a high voltage interlock function, and / or can detect and / or calculate an insulation and short circuit condition.

[0058] The relay can be a mechanical contactor turned on and off by a magnetic force of a coil, or a semiconductor switch such as a metal oxide semiconductor field effect transistor (MOSFET).

[0059] The relay control has a function of cutting off a power supply of the battery if a problem occurs in the vehicle and the battery system (or when a problem occurs in the vehicle and the battery system), and can include one or more relays and pre-charge relays at the positive electrode terminal and the negative electrode terminal, respectively.

[0060] In the pre-charge control, there is a risk of a surge current occurring in the high-voltage capacitor at the input side of the inverter when a battery load is connected. To prevent a surge current when starting the vehicle, a pre-charge relay can be operated before the main relay is connected, and a pre-charge resistor can be connected.

[0061] A high-voltage interlock is a circuit that uses a small signal to detect whether all high-voltage components of the entire vehicle system have been connected, and can have a function of forcibly opening a relay if (or when) an open circuit occurs at even one location on the entire loop.

[0062] FIG. 1A To illustrate a perspective view of a secondary battery according to one or more embodiments of the present disclosure, and FIG. 1B To illustrate a cross-sectional view taken along FIG. 1A line 1b-1b in FIG. 1A. Referring to FIG. 1A and FIG. 1B , a secondary battery 100 according to one or more embodiments of the present disclosure can include at least one electrode assembly 110 wound with a separator 113 as an insulator between a positive electrode 111 and a negative electrode 112, a case 120 in which the electrode assembly 110 is received (or housed), and a cap assembly 130 coupled to an opening of the case 120.

[0063] FIG. 1A and FIG. 1B The secondary battery 100 according to one or more embodiments illustrated in FIGS. 1A to 1C will now be described as an example of a prismatic lithium-ion secondary battery. However, the present disclosure is not limited thereto, and suitable aspects, features, and principles described herein can be applied to various other types of batteries such as lithium polymer batteries and / or cylindrical batteries.

[0064] Each of the positive electrode 111 and the negative electrode 112 can include a current collector made of a thin metal foil, having a coated portion coated with an active material, and an electrode uncoated portion 111a, 112a not coated with the active material.

[0065] The positive electrode 111 and the negative electrode 112 can be wound after the separator 113 as an insulator is interposed therebetween. However, the present disclosure is not limited thereto, and the electrode assembly 110 can have a structure in which the positive electrode 111 and the negative electrode 112 each made of a plurality of pieces are alternately stacked with the separator interposed therebetween.

[0066] The case 120 can form the overall appearance of the secondary battery 100, and can be made of an electrically conductive metal such as aluminum, an aluminum alloy, or nickel-plated steel. The case 120 can provide a space in which the electrode assembly 110 is housed.

[0067] The cover assembly 130 can include a cover plate 131 covering an opening in the case 120, and the case 120 and the cover plate 131 can be made of an electrically conductive material. Positive and negative electrode terminals 121 and 122 electrically connected to the positive and negative electrodes 111 and 112, respectively, can be mounted to penetrate (or extend through) the cover plate 131 and protrude outwardly therefrom.

[0068] The outer circumferential surface (e.g., the peripheral surface) of the upper column of the positive and negative electrode terminals 121 and 122 protruding outwardly from the cover plate 131 can be threaded, and can be fixed to the cover plate 131 by using a nut.

[0069] However, the present disclosure is not limited thereto, and the positive and negative electrode terminals 121 and 122 can have a rivet structure, and can be riveted or welded to the cover plate 131.

[0070] The cover plate 131 can be made of a thin plate, and can be coupled to the opening in the case 120, and an electrolyte injection port 132 in which a sealing plug 133 can be mounted can be located (e.g., formed) in the cover plate 131, and an exhaust portion 134 having a notch 134a can be mounted. In one or more embodiments, the exhaust portion 134 can block an exhaust hole provided in the cover plate 131. In one or more embodiments, the exhaust portion 134 can be joined or welded to a peripheral area (an area of the cover plate) of the exhaust hole.

[0071] The positive and negative electrode terminals 121 and 122 can be electrically connected to the positive and negative electrode uncoated portions 111a and 112a by being bonded or coupled (e.g., by welding) to current collectors including first and second current collectors 140 and 150 (hereinafter referred to as positive and negative electrode current collectors), respectively.

[0072] For example, the positive and negative electrode terminals 121 and 122 can be coupled to the positive and negative electrode current collectors 140 and 150 by welding, respectively. However, the present disclosure is not limited thereto, and in one or more embodiments, the positive and negative electrode terminals 121 and 122 and the positive and negative electrode current collectors 140 and 150 can be integrally formed.

[0073] An insulating member can be mounted between the electrode assembly 110 and the cover plate 131. The insulating member can include first and second lower insulating members 160 and 170, and each of the first and second lower insulating members 160 and 170 can also have a portion located between the electrode assembly 110 and the case 120.

[0074] According to one or more embodiments of the disclosure, one end of the separation member can face one side of the electrode assembly 110, and can be installed between the insulating member and the positive electrode terminal 121 or the negative electrode terminal 122.

[0075] In one or more embodiments, the separation member can include a first separation member 180 and a second separation member 190.

[0076] In such an embodiment, the first ends of the first and second separation members 180 and 190, which are installed to face one side of the electrode assembly 110, can be installed between the first lower insulating member 160 and the positive electrode terminal 121 and between the second lower insulating member 170 and the negative electrode terminal 122, respectively.

[0077] The positive and negative electrode terminals 121 and 122, which can be coupled to the positive and negative electrode current collectors 140 and 150 by welding, can be coupled to the first and second lower insulating members 160 and 170 and the first ends of the first and second separation members 180 and 190.

[0078] FIG. 2 A perspective view of a battery module according to one or more embodiments of the disclosure is illustrated. Referring to FIG. 2 , the battery module 200 according to one or more embodiments of the disclosure includes a plurality of battery cells 100 (such as battery cells 100a, 100b, etc.) arranged in one direction and having electrode terminals 121 and 122, a connection tab 220 connecting the battery cell 100a to an adjacent battery cell 100b, and a protection circuit module 230 having one end connected to the connection tab 220. The protection circuit module 230 can include a battery management system (BMS). Further, the connection tab 220 can include a main body portion in contact with the electrode terminals 121 and 122 of the adjacent battery cells 100a and 100b and an extension portion extending from the main body portion and connected to the protection circuit module 230. The connection tab 220 can be, for example, a bus bar.

[0079] Each battery cell 100 can include a battery case, an electrode assembly received (or housed) in the battery case, and an electrolyte. The electrode assembly and the electrolyte undergo an electrochemical reaction to store and release (e.g., generate) energy. Electrode terminals 121 and 122 electrically connected to the connection tabs 220 and an exhaust portion 134 as a discharge passage for gas generated inside the battery case can be provided at one side (e.g., an upper side) of the battery cell 100. The electrode terminals 121 and 122 of the battery cell 100 can be a positive electrode terminal 121 and a negative electrode terminal 122 having different polarities from each other, and the electrode terminals 121 and 122 of adjacent battery cells 100a and 100b can be electrically connected to each other in series or in parallel through the connection tabs 220, which will be described in more detail below. Although a series connection has been described as an example, the connection structure is not limited thereto, and various connection structures can be employed as desired or needed. The number and arrangement of battery cells are not limited to FIG. 2 the structure shown in FIG. 1, and can be changed as desired or needed.

[0080] A plurality of battery cells 100 can be arranged (e.g., can be stacked) in one direction such that the wide surfaces of the battery cells 100 face each other, and the plurality of battery cells 100 can be fixed by the housings 261, 262, 263, and 264. The housings 261, 262, 263, and 264 can include a pair of end plates 261 and 262 facing the wide surfaces of the battery cells 100 and a side plate 263 and a bottom plate 264 connecting the pair of end plates 261 and 262 to each other. The side plate 263 can support the side surfaces of the battery cells 100, and the bottom plate 264 can support the bottom surfaces of the battery cells 100. The pair of end plates 261 and 262, the side plate 263, and the bottom plate 264 can be connected by bolts 265 and / or any other suitable fastening members and / or methods known to one of ordinary skill in the art.

[0081] The protection circuit module 230 can have electronic components and protection circuits mounted thereon and can be electrically connected to the connection tabs 220, which will be described later in more detail. The protection circuit module 230 includes a first protection circuit module 230a and a second protection circuit module 230b extending in a direction along which the plurality of battery cells 100 are arranged at different positions. The first protection circuit module 230a and the second protection circuit module 230b can be spaced apart from each other at a suitable interval (e.g., a predetermined interval) and arranged in parallel to each other to be electrically connected to the adjacent connection tabs 220, respectively. For example, the first protection circuit module 230a extends in the direction along which the plurality of battery cells 100 are arranged at one side of an upper portion of the plurality of battery cells 100, and the second protection circuit module 230b extends in the direction along which the plurality of battery cells 100 are arranged at the other side of the upper portion of the plurality of battery cells 100. The second protection circuit module 230b can be spaced apart from the first protection circuit module 230a at a suitable interval (e.g., a predetermined interval) with the exhaust portion 134 interposed therebetween, but can be positioned parallel to the first protection circuit module 230a. Thereby, the two protection circuit modules are spaced apart from each other side by side in the direction along which the plurality of battery cells 100 are arranged, thereby reducing or minimizing the area of a printed circuit board (PCB) constituting the protection circuit module. By separately configuring the protection circuit module as two protection circuit modules, it is possible to reduce or minimize unnecessary PCB area. The first protection circuit module 230a and the second protection circuit module 230b can be connected to each other by a conductive connection member 250. One side of the conductive connection member 250 is connected to the first protection circuit module 230a, and the other side thereof is connected to the second protection circuit module 230b, so that the two protection circuit modules 230a and 230b can be electrically connected to each other.

[0082] The connection can be performed by any one of soldering, resistance welding, laser welding, projection welding, and / or any other suitable connection method known to those of ordinary skill in the art.

[0083] The connection member 250 can be, for example, an electric wire. The connection member 250 can be made of a material having elasticity or flexibility. By the connection member 250, it can be possible to check whether the voltage, temperature, and / or current of the plurality of battery cells 100 are normal. For example, information such as voltage, current, and / or temperature received by the first protection circuit module from the connection tabs adjacent to the first protection circuit module and information such as voltage, current, and / or temperature received by the second protection circuit module from the connection tabs adjacent to the second protection circuit module can be integrated and managed by the protection circuit module through the connection member 250.

[0084] If the battery cell 100 swells, an impact can be absorbed due to the elasticity or flexibility of the connection member 250, thereby preventing the first and second protection circuit modules 230a and 230b from being damaged.

[0085] The shape and structure of the connection member 250 are not limited to FIG. 2 the shape and structure shown in

[0086] As described above, because the protection circuit module 230 is provided as the first and second protection circuit modules 230a and 230b, the area of the PCB constituting the protection circuit module can be reduced or minimized, and the space inside the battery module can be secured, which improves work efficiency by facilitating the fastening work for connecting the connection tabs 220 and the protection circuit module 230 and the repair work if an abnormality is detected in the battery module (or when an abnormality is detected in the battery module).

[0087] FIG. 3A and FIG. 3B A battery pack 300 according to one or more embodiments of the disclosure is illustrated. The battery pack 300 can include a plurality of battery modules 200 and a housing 310 for accommodating the plurality of battery modules 200. For example, the housing 310 can include a first housing 311 and a second housing 312 coupled in opposite directions with respect to the plurality of battery modules 200. The plurality of battery modules 200 can be electrically connected to each other by using the bus bars 251, and the plurality of battery modules 200 can be electrically connected to each other in a series / parallel or series-parallel hybrid method, thereby obtaining a desired (e.g., required) electrical output.

[0088] FIG. 4A and FIG. 4B A vehicle body 400 and a vehicle 500 including the battery pack 300 illustrated in FIG. 3A and FIG. 3B In FIG. 4A , the battery pack 300 can include a battery pack cover 311' that is a part of a vehicle bottom 410 and can correspond to the first housing 311, and a pack frame 312' that is located under the vehicle bottom 410 and can correspond to the second housing 312. The battery pack cover 311' and the pack frame 312' can be integrally formed with a vehicle floor 420 of the vehicle. The vehicle bottom 410 separates the inside and outside of the vehicle, and the pack frame 312' can be located outside the vehicle.

[0089] In FIG. 4BIn the middle, the vehicle 500 can be formed by combining additional parts, such as a hood 510 in front of the vehicle 500 and bumpers 520 in front and rear of the vehicle 500, respectively, to the body 400. The vehicle 500 can include the battery pack 300 including the battery pack cover 311' and the pack frame 312', and the battery pack 300 can be coupled to the body 400.

[0090] FIG. 5A to FIG. 5B A schematic diagram illustrating a charging method for a secondary battery is shown. In one or more embodiments, the secondary battery can be charged and discharged, for example, in the following manner.

[0091] Constant current constant voltage (CCCV) charging is a charging method that performs constant current (CC) charging until a voltage reaches a suitable voltage or a reference voltage (e.g., a predetermined voltage) and then performs constant voltage (CV) charging until an amount of current flowing is reduced, for example, until a final current value is achieved.

[0092] During CC charging, as shown in FIG. 5A , a switch of a constant current power source is turned on and a switch of a constant voltage power source is turned off, so that a constant current I flows through the secondary battery. During this period, because the current I is constant, a voltage V R applied to an internal resistance R is also constant according to Ohm's law (V R = R x I). A voltage V C applied to a secondary battery capacitor C increases over time. The secondary battery voltage V B may rise over time.

[0093] When (or if) the secondary battery voltage V B reaches a suitable voltage or a reference voltage (e.g., a predetermined voltage) (e.g., about 4.3 V), the CC charging switches to CV charging. During CV charging, as shown in FIG. 5B , the switch of the constant voltage power source is turned on and the switch of the constant current power source is turned off, so that the secondary battery voltage V B is constant. The voltage V C applied to the secondary battery capacitor C increases over time. Because V B = V R + V C is satisfied, the voltage V R applied to the internal resistance R decreases over time. With the decrease in the voltage V R applied to the internal resistance R, the current I flowing through the secondary battery can also decrease according to Ohm's law (V R = R x I).

[0094] When (or if) the current I flowing through the secondary battery reaches a suitable current or reference current (e.g., a predetermined current) (e.g., approximately 0.01C), the charging is terminated. When (or if) the CCCV charging is completed, all switches are turned off and the current I becomes 0, as shown in FIG. 2B. At this time, the voltage V applied to the internal resistance R becomes 0V. Even though the voltage drop on the internal resistance R is prevented, the secondary battery voltage V FIG. 5C R does not substantially decrease. B

[0095] FIG. 5D A graph showing the secondary battery voltage V B and the charging current during the CCCV charging and after the CCCV charging termination is shown in FIG. 2C. Even after the CCCV charging termination, the secondary battery voltage V B does not substantially decrease.

[0096] In one or more embodiments, the secondary battery can be used as a battery module composed of a plurality of battery cells connected in series and / or in parallel to each other to provide a high energy density. The battery module can be formed by interconnecting electrode terminals of a plurality of battery cells to realize a high-output secondary battery according to a suitable amount of power. A structure in which a plurality of battery modules are connected in series and / or in parallel to each other can be referred to as a battery pack.

[0097] The battery module can be constructed in a block design or a modular design. In the block design, each battery cell can be coupled to a common current collecting structure and a common battery management system. In the modular design, a plurality of battery cells can be connected to each other to form a sub-module, and a plurality of sub-modules can be connected to each other to form a battery module. The battery management function can be implemented at the module level or the sub-module level to improve interchangeability of components. To realize a battery system, one or more battery modules can be mechanically and electrically integrated, can be equipped with a thermal management system, and can be provided to communicate with one or more power consumers.

[0098] The mechanical integration of the battery module can be achieved by providing a cooling plate and placing each battery cell or sub-module thereon. The fixation of the battery cell or sub-module can be achieved by a recessed portion or a mechanical interconnector such as a bolt or a screw formed in the cooling plate. In one or more embodiments, the battery cell or sub-module can be restrained by fastening a side plate to a side surface of the cooling plate.

[0099] ​​To provide thermal control of the battery pack, the thermal management system can be adapted to safely use at least one battery module by effectively radiating, releasing, and / or dissipating heat generated by the secondary battery. If the heat is not sufficiently radiated / released / dissipated, temperature deviation can occur between the battery cells, such that at least one battery module can not generate a desired amount of power. An increase in the internal temperature can cause an abnormal reaction to occur therein, potentially causing deterioration of the charging / discharging performance of the secondary battery and / or shortening of its lifespan. It is desirable to develop a cell cooling mechanism for effectively radiating, releasing, and / or dissipating heat generated in the cell.

[0100] Thermal runaway is an example of an abnormal operating state of a battery cell that can occur due to a lithium ion battery cell being severely overheated or overcharged. The critical temperature at which thermal runaway is transitioned can be about 150°C or more, and heat can propagate from a battery cell having a defective electrical contact or a short circuit to another battery cell adjacent thereto. Thermal runaway can be a self-accelerating chemical reaction in a cell. Such thermal runaway can generate a large amount of heat and gas until all available materials are depleted. During thermal runaway, a defective cell can be heated to a cell temperature of about 800°C or more, and a large amount of hot gas can be discharged to the inside of the system. The battery cell can generally include a gas discharge hole formed therein so as to discharge a gas if a pressure in the battery cell exceeds a reference pressure. In a cell housing having a high energy density (e.g., about 200 Wh / kg), the discharged gas can have a temperature of about 500°C and a gas velocity of about 300 m / s.

[0101] During thermal runaway, a large amount of heat can propagate to adjacent cells due to the gas discharge. Since these cells are heated by the faulty cell due to heat conduction through their side plates, base plates, and / or electrical connectors, the cells are likely to experience thermal runaway. This can result in thermal runaway propagation and a battery fire of the entire battery system.

[0102] In general, an energy storage system installed in a container, an enclosure, a building, or a dedicated building can include a fire extinguishing system to extinguish a fire when it occurs due to an electric shock, a short circuit, or an external surge, etc.

[0103] Recently, a direct injection type fire extinguishing system has been employed in which, if an event occurs in a certain battery cell, a fire extinguishing guide pipe is opened, and an opening of a gas discharge portion of the battery cell is detected, so that a fire extinguishing agent is directly injected into the inside / outside of the battery cell in which the event occurs. Such a direct injection type fire extinguishing system can be adapted to the trend toward higher capacity battery cells.

[0104] In one or more embodiments, the direct-injection fire suppression system can perform a method of extinguishing a fire in response to flames and / or smoke from the battery cell when an event occurs in the cell. In one or more embodiments, flames emitted from the venting section of the cell can melt the polymer resin of the agent injection nozzle blocking the fire extinguishing conduit, and a temperature sensor or smoke sensor can detect the temperature or the amount of smoke and send an open signal to the fire extinguishing agent supply, thereby allowing the fire extinguishing agent to be directly injected into the cell where the event has occurred through the open nozzle of the fire extinguishing conduit.

[0105] In one or more embodiments, the extinguishing conduit of a direct-injection fire suppression system can be machined by forming through-holes in the extinguishing conduit to serve as nozzles. The through-holes in the extinguishing conduit can be blocked by a polymer material via a separate insert injection molding process. The polymer injection-molded portion can block the through-holes to seal the extinguishing conduit under normal conditions. When an incident occurs in a monomer, the polymer injection-molded portion can be melted by the flame, and then the nozzle can be opened by the pressure of the injected extinguishing agent, allowing the extinguishing agent to reach the monomer where the incident occurred. Thus, the opening of the nozzle during an incident can depend on the temperature of the flame and / or may depend on the duration of exposure to the flame.

[0106] In the early stages of a monomer's life (e.g., a monomer with 100% charge), the temperature of the flame emanating directly from the monomer may be approximately 800°C or higher, and opening a nozzle located above the exhaust section may not be a problem. In the late stages of a monomer's life, or in structures where it is difficult or impossible to place the extinguishing conduit directly above the exhaust section (e.g., via a heat transfer medium), the temperature delivered to the nozzle may be relatively low, and the heat transfer path may be relatively long. The polymer resin blocking the nozzle may not melt, and the nozzle may not open at the appropriate time, potentially leading to extinguishing failure.

[0107] It is desirable to develop a direct-spray fire suppression system that can stably open its nozzles even at temperatures below about 800°C. In this disclosure, temperatures below about 800°C can be defined as low temperature.

[0108] FIG. 6 A schematic diagram of a direct-injection battery pack fire suppression system 600 according to this disclosure is shown. FIG. 6 As shown, in one or more embodiments, the direct-injection battery pack fire suppression system 600 may include a fire extinguishing agent supply 610 configured to supply fire extinguishing agent to the battery pack 300 or battery module 200, a fire extinguishing conduit 620 configured to deliver and spray the fire extinguishing agent, and a sensor configured to detect a fire. In one or more embodiments, the battery pack 300 or battery module 200 may include, or may be referred to as, an energy storage system.

[0109] In one or more embodiments, the extinguishing agent supply device 610 may include an extinguishing agent spray container 611 configured to store extinguishing agent, a discharge valve 612 for spraying extinguishing agent, a regulator 613 configured to adjust the supply pressure and supply time of extinguishing agent, and a controller for controlling the system.

[0110] The extinguishing agent dispensing container 611 can be a pressure vessel for storing extinguishing agents. Depending on whether the extinguishing agent dispensing container 611 can be installed independently, it can be classified as self-supporting or attached to a support structure. In one or more embodiments, the extinguishing agent may include Novec. TM 1230 (Novec) TM (A registered trademark of 3M Corporation, Delaware, USA). Compressed gases used for spraying extinguishing agents may include nitrogen.

[0111] If the controller decides to spray the extinguishing agent, it can open the discharge valve 612 to allow the extinguishing agent to be sprayed. The discharge valve 612 can be used to open or close the extinguishing agent spray container 611. If the discharge valve 612 is open, the extinguishing agent can be discharged and moved to the regulator 613. The regulator 613 can be used to adjust the spray pressure of the extinguishing agent to the final spray pressure. For this purpose, the regulator 613 may include a pressure regulator.

[0112] The fire extinguishing conduit 620 may include a main pipe, branch pipes, and a spray pipe extending from the fire extinguishing agent supply 610 to each of the plurality of battery modules 200 of the battery pack 300. In one or more embodiments, the plurality of battery modules 200 may be mounted on a plurality of battery racks, and the branch pipes and spray pipes for spraying the fire extinguishing agent may be mounted to each battery rack.

[0113] If a fire occurs in battery module 200, the sensor can detect the fire, and extinguishing agent can be supplied from extinguishing agent supply unit 610 and sprayed into battery module 200 through extinguishing conduit 620. The extinguishing agent can be rapidly sprayed into battery module 200, thereby extinguishing the fire in battery module 200.

[0114] In the following text, for ease of description, the main pipe, branch pipes and spray pipes will be collectively referred to as fire extinguishing conduit 620, and the fire extinguishing conduit 620 and the heat-sensitive components 630 connected thereto will be described in detail.

[0115] FIG. 7 A side view is shown for illustrating a direct-injection battery pack fire suppression system 600 according to this disclosure. FIG. 7In the example shown in FIG. 1, the battery module 200 can include a plurality of battery cells 100 arranged in line with each other along a first direction (e.g., the Y direction). In one or more embodiments, each battery cell 100 can be a prismatic (or rectangular) cell, and the wide flat sidewalls 124, 125 of the battery cells 100 can be stacked together to form the battery module 200. In one or more embodiments, the battery cells 100 can be arranged such that the sidewalls 124, 125 of adjacent battery cells 100 face and / or are in close contact with each other. In one or more embodiments, a separator made of an organic material and / or an inorganic material to reduce or prevent heat propagation can be located between the sidewalls 124, 125 of adjacent battery cells 100. In one or more embodiments, the positive and negative electrode terminals of adjacent battery cells 100 can be electrically connected to each other by a busbar, respectively. The plurality of battery cells 100 can be electrically connected to each other in a bundle to use the battery module 200 as a power source. In some embodiments, a plurality of battery modules 200 can be electrically connected to each other to form a battery pack 300, and the battery pack 300 can be used as a power source.

[0116] As described above, each battery cell 100 can include an exhaust portion 134 located in the cover assembly 130 of the battery cell 100 at a distance from the positive and negative electrode terminals 121, 122 (see, e.g., FIG. 1). The exhaust portions 134 of the plurality of battery cells 100 arranged along the first direction can also be arranged along the first direction (for the understanding of the present disclosure, FIG. 1A and FIG. 1B ). In some embodiments, the plurality of battery cells 100 can be located on a cooling plate 601 configured to support the weight of the battery cells 100 and configured to cool the battery cells 100. FIG. 7

[0117] ​The direct injection type battery pack fire extinguishing system 600 can include the above-described fire extinguishing conduit 620 and a plurality of heat-sensitive members 630. The fire extinguishing conduit 620 can include injection holes 621 formed in the fire extinguishing conduit 620 to inject the fire extinguishing agent to the exhaust portion 134 (or exhaust hole) of the battery cell 100. In one or more embodiments, one end of the fire extinguishing conduit 620 can be blocked by a plug 622. The heat-sensitive member 630 can be coupled to the fire extinguishing conduit 620 while blocking the injection hole 621. In one or more embodiments, the number of injection holes 621 formed in the fire extinguishing conduit 620 can correspond to the number of exhaust portions 134 formed in the battery cell 100. In one or more embodiments, at least one injection hole 621 (for example, two injection holes 622) can correspond to each exhaust portion 134. In one or more embodiments, each heat-sensitive member 630 can include a body portion 631 surrounding (for example, at least partially surrounding) the outer circumference of the fire extinguishing conduit 620 and a nozzle portion 632 located in a region corresponding to the injection hole 621 and having a thickness smaller than that of the body portion 631.

[0118] A portion of the nozzle portion 632 of the heat-sensitive member 630 corresponding to the battery cell 100 in which the event occurs can be melted, and the fire extinguishing agent can be injected only to the battery cell 100 in which the event occurs. The temperature of the battery cell 100 in which the event occurs can be reduced, and heat can not be transmitted to another normal battery cell 100 adjacent to the battery cell 100 in which the event occurs. For example, the thermal runaway phenomenon can not be transmitted to another cell adjacent to the cell in which the event occurs.

[0119] In one or more embodiments, the battery module 200 can be spaced apart in the second direction (for example, the X direction). The above-described fire extinguishing conduit 620 and the above-described heat-sensitive member 630 can also be spaced apart in the second direction above the battery module 200. In one or more embodiments, a plurality of battery modules 200 can be referred to as a battery pack 300.

[0120] FIG. 8A and FIG. 8B is shown to illustrate the operation of the direct injection type battery pack fire extinguishing system 600 according to the present disclosure. As shown in FIG. 8A is shown (for example, referring to the third cell from the left in FIG. 8A , the exhaust can be discharged through the exhaust portion 134 of a certain battery cell 100 (for example, in which an event can occur). Upon determining that the detected temperature of the battery cell 100 exceeds the reference value or the detected amount of smoke from the battery cell 100 exceeds the reference value, the controller can open the valve 612. The fire extinguishing agent can be supplied from the fire extinguishing agent injection container 611 to the fire extinguishing conduit 620. As shown in FIG. 8BAs shown, the portion of the heat-sensitive component 630 corresponding to the exhaust can be melted by the exhaust or surrounding heat, so that the extinguishing agent in the fire extinguishing conduit 620 can be directly sprayed onto the exhaust portion 134 of the battery cell 100.

[0121] FIG. 9A , FIG. 9B and FIG. 9C The figures show a plan view and a cross-sectional view of the fire extinguishing conduit 620 and the heat-sensitive component 630 in the direct-injection battery pack fire extinguishing system 600 according to the present disclosure, respectively. FIG. 9B and FIG. 9C For along FIG. 9A The cross-sectional view is taken from line 9b-9b. For ease of description, the fire extinguishing conduit 620 and the heat-sensitive component 630 are shown in an inverted state. FIG. 9A and FIG. 9B As shown, the direct-injection battery pack fire suppression system 600 may include a fire suppression conduit 620 and a heat-sensitive component 630. In one or more embodiments, the fire suppression conduit 620 may include or be made of a conductive material (such as aluminum, copper, or stainless steel), and the heat-sensitive component 630 may include or be made of a polymer (such as acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), or perfluoroalkoxyolefin (PFA)).

[0122] In one or more embodiments, two injection holes 621 may be formed in the portion of the fire extinguishing conduit 620 corresponding to a heat-sensitive member 630. In one or more embodiments, the heat-sensitive member 630 may include a body portion 631 surrounding the outer periphery of the fire extinguishing conduit 620, and may also include a nozzle portion 632 located in the area corresponding to the injection holes 621 and having a thickness less than that of the body portion 631. In one or more embodiments, the nozzle portion 632 may include two recessed portions 6321 formed in the body portion 631 recessed toward the two injection holes 621, and may also include two thin film portions 6322 formed at the bottom of the two recessed portions 6321 and having a thickness less than that of the body portion 631. A rib 6324 with a relatively large thickness may be formed between the two recessed portions 6321. The rib 6324 may be used to reduce or prevent the area between the two thin film portions 6322 from melting before the two thin film portions 6322 melt.

[0123] In one or more embodiments, the nozzle portion 632 can further include an extended recessed portion 6325 formed outside the recessed portion 6321, having a diameter larger than that of the recessed portion 6322, having a thickness smaller than that of the main body portion 631, and having a thickness larger than that of the thin film portion 6322. For example, two recessed portions 6321 can be located inside one extended recessed portion 6325.

[0124] In one or more embodiments, the diameter of the recessed portion 6321 can be smaller than the diameter of the ejection hole 621. In one or more embodiments, the diameter of the ejection hole 621 can be about 6% to about 30% of the entire cross-sectional arc length of the fire extinguishing conduit 620. The diameter of the recessed portion 6321 can also be about 6% to about 30% of the entire cross-sectional arc length of the fire extinguishing conduit 620. If the diameter of the ejection hole 621 is smaller than about 6% of the entire cross-sectional arc length of the fire extinguishing conduit 620, the heat transfer efficiency of the exhaust gas can decrease, and the thin film portion 6322 can not be melted at a desired time. If the diameter of the ejection hole 621 is larger than about 30% of the entire cross-sectional arc length of the fire extinguishing conduit 620, the durability of the thin film portion 6322 can decrease, and the thin film portion 6323 can be damaged by external impact.

[0125] In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 can be larger than the thickness of the thin film portion 6322. In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 can be about 1.5 times to about 3 times the thickness of the thin film portion 6322. In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 can be about 0.15 mm to about 1.5 mm. The heat sensitive member 630 can be formed on the fire extinguishing conduit 620 by a double injection molding process. It can be difficult to make the thickness of the inner wall 6323 of the recessed portion 6321 smaller than about 0.15 mm due to the design tolerance of the injection mold. If the thickness of the inner wall 6323 of the recessed portion 6321 is larger than about 1.5 mm, the area of the thin film portion 6322 can decrease, and the efficiency of the ejection of the fire extinguishing agent can decrease.

[0126] In one or more embodiments, the thickness of the thin film portion 6322 can be about 0.1 mm to about 0.5 mm. If the thickness of the thin film portion 6322 is smaller than about 0.1 mm, the thin film portion 6322 can be more easily damaged by external impact. If the thickness of the thin film portion 6322 is larger than about 0.5 mm, it can take a relatively very long time for the thin film portion 6323 to be melted, which can decrease the efficiency of the fire extinguishing.

[0127] In one or more embodiments, the diameter of the injection hole 621 can correspond to an angle θ of about 30° to about 90° about the center of the fire extinguishing conduit 620 (e.g., the center of the diameter of the fire extinguishing conduit 620). The diameter of the recessed portion 6321 can also correspond to an angle θ of about 30° to about 90° about the center of the diameter of the fire extinguishing conduit 620. If the diameter of the injection hole 621 is less than about 30°, the heat transfer efficiency through the exhaust gas can decrease, and the thin film portion 6322 can not melt at a desired time. If the diameter of the injection hole 621 is greater than about 90°, the durability of the thin film portion 6322 can decrease, and the thin film portion 632 can be damaged by external impact.

[0128] In one or more embodiments, the height of the inner wall 6323 of the recessed portion 6321 can be about 0.5 mm to about 3 mm. The recessed portion 6321 can be stably coupled to the injection hole 621 in the fire extinguishing conduit 620, and the durability thereof can be secured.

[0129] In one or more embodiments, the thin film portion 6322 can melt at a temperature in a range of about 150°C to about 500°C. In one or more embodiments, the heat-sensitive member 630 can melt at a temperature in a range of about 150°C to about 500°C. Because the thickness of the thin film portion 6322 is less than the thickness of the main body portion 631, the thin film portion 6322 can be relatively quickly opened. In one or more embodiments, the recessed portion 6321 and the thin film portion 6322 can be provided to correspond to the exhaust portion 134 of the battery cell 100, so that the thin film portion 6322 can be immediately melted by the exhaust gas discharged from the exhaust portion 134.

[0130] In this way, according to the present disclosure, the nozzle portion 632 of the direct injection type fire extinguishing conduit 620 for extinguishing a fire in the battery pack 300, the battery module 200, or the energy storage system can be stably opened even at a relatively low temperature. For example, a typical nozzle portion opening mechanism is as follows: the presence of a flame causes an increase in the temperature of the heat-sensitive member 630 and the fire extinguishing conduit 620, which causes the melting of the heat-sensitive member 630. A portion of the heat suitable for melting the heat-sensitive member 630 can be transferred to the fire extinguishing conduit 620, and a relatively large amount of heat can suitably open the nozzle portion 632.

[0131] If the amount of heat transferred to the fire extinguishing conduit 620 is reduced or minimized, the heat-sensitive member 630 can be quickly melted or melted at a low temperature. According to the present disclosure, the amount of heat transferred to the fire extinguishing conduit 620 can be reduced or minimized with a suitable structure, thereby allowing the nozzle portion 632 to be opened even at a relatively low temperature. In FIG. 9B In FIG. 6, three thick arrows indicate heat transfer paths created by the exhaust gas traveling to the thin film portion, and two dotted arrows on both sides indicate heat transfer paths created by the exhaust gas traveling to the fire extinguishing conduit. As shown in FIG. 6, the heat transfer paths created by the exhaust gas traveling to the thin film portion are more than the heat transfer paths created by the exhaust gas traveling to the fire extinguishing conduit. FIG. 9BAs shown in FIG. 6, the amount of heat transferred to the film portion can be greater than the amount of heat transferred to the fire extinguishing guide pipe.

[0132] For example, the temperature of heat generated during thermal runaway of a cell at the end of life can be about 420°C, which is lower than the temperature of a flame emitted from a cell at the beginning of life (e.g., a cell having a state of charge of 100%). Experiments confirm that the nozzle portion 632 normally opens at a relatively low temperature due to the above-described structure, with the result that the fire extinguishing agent is sprayed at a desired time, and a fire is extinguished without thermal runaway.

[0133] FIG. 10 A block diagram showing an electrical configuration of the direct injection battery pack fire extinguishing system 600 according to the present disclosure is shown. As shown in FIG. 6, the direct injection battery pack fire extinguishing system 600 can further include a temperature sensor 641, a smoke sensor 642, a controller 643, and a valve 612. FIG. 10 As shown in FIG. 6, the direct injection battery pack fire extinguishing system 600 can further include a temperature sensor 641, a smoke sensor 642, a controller 643, and a valve 612.

[0134] The temperature sensor 641 can detect the temperature of the battery cell 100, and can transmit temperature information to the controller 643. In one or more embodiments, one temperature sensor 641 can be installed in each of the battery modules 200, or one temperature sensor 641 can be installed in each of the battery cells 100. In one or more embodiments, the temperature sensor 641 can be installed adjacent to the exhaust portion 134.

[0135] The smoke sensor 642 can detect the amount of smoke emitted from the battery cell 100, and can transmit smoke information to the controller 643. In one or more embodiments, one smoke sensor 642 can be installed in each of the battery modules 200, or one smoke sensor 642 can be installed in each of the battery cells 100. In one or more embodiments, the smoke sensor 642 can be installed adjacent to the exhaust portion 134.

[0136] The controller 643 can receive temperature information and / or smoke information about the battery cell 100 from the temperature sensor 641 and / or the smoke sensor 642, and can perform various control operations based on the temperature information and / or the smoke information.

[0137] The valve 612 can be installed to the fire extinguishing agent spraying container 611 as described above, and can be opened or closed in response to a control signal from the controller 643. In one or more embodiments, the valve 612 can include an electronic valve 612 configured to be opened or closed in response to an electronic signal.

[0138] In one or more embodiments, upon determining that the temperature of the battery cell 100 exceeds the reference value and / or the amount of smoke from the battery cell 100 exceeds the reference value, the controller 643 can transmit a control signal for opening the valve 612 to the valve 612. The fire extinguishing agent can be completely sprayed to the battery cell 100 from the fire extinguishing agent spray container 611 through the fire extinguishing conduit 620 and the heat-sensitive member 630.

[0139] In one or more embodiments, the valve 612 can further include a temperature-sensitive valve. In one or more embodiments, if the ambient temperature is higher than a reference value, the valve 612 can be opened without a control signal from the controller 643. High pressure can be applied to the fire extinguishing conduit 620, and if the pressure exceeds a reference value, the nozzle portion 632 of the heat-sensitive member 630 can be broken, and the spray hole 621 can be opened. Thereby, even if exhaust gas is not discharged from the battery cell 100, if the temperature of the battery module 200 (e.g., the ambient temperature of the valve 612) exceeds a reference value, the fire extinguishing agent can be automatically supplied to the battery module 200.

[0140] As is apparent from the above description, the present disclosure can provide a battery pack fire extinguishing system configured to spray a fire extinguishing agent to a corresponding battery cell even when a low temperature event occurs in the battery cell of the battery pack, thereby reducing the temperature of the corresponding battery cell and the temperature of the battery cells in the vicinity, and reducing or preventing heat propagation to another battery cell adjacent to the corresponding battery cell.

[0141] Although the present disclosure has been described with reference to embodiments and drawings illustrating aspects thereof, the present disclosure is not limited thereto. Those skilled in the art to which the present disclosure pertains can make various modifications and changes within the technical spirit of the present disclosure and the claims and their equivalents.

Claims

1. A fire extinguishing system for a plurality of battery cells, characterized by, The fire extinguishing system includes: a fire extinguishing guide pipe defining an injection hole for injecting a fire extinguishing agent into an exhaust hole of one of the plurality of battery cells; and a heat-sensitive member blocking the injection hole and including: a body portion at least partially surrounding an outer circumference of the fire extinguishing guide pipe; and a nozzle portion corresponding to the injection hole and having a thickness smaller than that of the body portion.

2. The fire extinguishing system of claim 1, wherein, The nozzle portion includes: a recessed portion in the body portion and recessed toward the injection hole; and a thin film portion at a bottom of the recessed portion and having a thickness smaller than that of the body portion.

3. The fire extinguishing system of claim 2, wherein, The nozzle portion further includes an extended recessed portion outside the recessed portion, having a diameter larger than that of the recessed portion, having a thickness smaller than that of the body portion, and having a thickness larger than that of the thin film portion.

4. The fire extinguishing system of claim 2, wherein, The diameter of the recessed portion is smaller than that of the injection hole.

5. The fire extinguishing system according to any one of claims 1 to 4, characterized in that The diameter of the injection hole is 6% to 30% of a cross-sectional arc length of the fire extinguishing guide pipe.

6. The fire extinguishing system according to any one of claims 2 to 4, characterized in that The recessed portion includes an inner wall having a thickness larger than that of the thin film portion.

7. The fire extinguishing system according to any one of claims 2 to 4, characterized in that, The recessed portion includes an inner wall having a thickness 1.5 times to 3 times that of the thin film portion.

8. The fire extinguishing system according to any one of claims 2 to 4, characterized in that The recessed portion includes an inner wall having a thickness of 0.15 mm to 1.5 mm.

9. The fire extinguishing system according to any one of claims 2 to 4, characterized in that, The thickness of the thin film portion is 0.1 mm to 0.5 mm.

10. The fire extinguishing system according to any one of claims 1 to 4, characterized in that The diameter of the injection hole corresponds to an angle of 30° to 90° around a center of the fire extinguishing guide pipe.

11. The fire extinguishing system according to any one of claims 2 to 4, characterized in that The recessed portion includes an inner wall having a height of 0.5 mm to 3 mm.

12. The fire extinguishing system according to any one of claims 2 to 4, characterized in that The thin film portion is configured to melt at a temperature of 150°C to 500°C.

13. The fire extinguishing system according to any one of claims 2 to 4, characterized in that The thin film portion is configured to melt by exhaust gas discharged from the exhaust hole of the one of the plurality of battery cells.

14. The fire extinguishing system of any one of claims 1 to 4, wherein, The fire extinguishing system further includes: a temperature sensor configured to detect a temperature of the one of the plurality of battery cells; a smoke sensor configured to detect an amount of smoke from the one of the plurality of battery cells; a controller configured to receive temperature information about the one of the plurality of battery cells from the temperature sensor or smoke information about the one of the plurality of battery cells from the smoke sensor; and a valve between the fire extinguishing guide pipe and a fire extinguishing agent injection container and configured to open or close in response to a control signal from the controller, the controller being configured to open the valve when it is determined that the temperature exceeds a reference value or the amount of smoke exceeds a reference value.

15. The fire extinguishing system according to any one of claims 1 to 4, characterized in that The fire extinguishing guide pipe is made of aluminum, copper, or stainless steel, and wherein the heat-sensitive member is made of acrylonitrile-butadiene-styrene, polypropylene, polycarbonate, polyethylene, or perfluoroalkoxy alkylene.

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