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 - reference to related applications

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

[0003] Aspects of embodiments of the present disclosure relate to a battery pack fire extinguishing system. Background art

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

[0005] The above information disclosed in this background art section is for enhancing the understanding of the background of the present disclosure, and thus may include information that does not constitute related (or prior) art. Summary of the invention

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

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

[0008] An extinguishing system for a plurality of battery cells according to one or more embodiments of the present disclosure includes: a fire - extinguishing conduit defining a spray hole for spraying a fire - extinguishing agent into an exhaust hole of one of the plurality of battery cells; and a thermosensitive member blocking the spray hole and including a body portion and a nozzle portion, the body portion at least partially surrounding an outer periphery of the fire - extinguishing conduit, the nozzle portion corresponding to the spray hole and having a thickness smaller than a thickness of the body portion.

[0009] The nozzle portion may include: a recessed portion, in the body portion and recessed toward the injection hole; and a thin film portion, at the bottom of the recessed portion and having a thickness smaller than the thickness of the body portion.

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

[0011] The diameter of the recessed portion may be smaller than the diameter of the injection hole.

[0012] The diameter of the injection hole may be about 6% to about 30% of the cross-sectional arc length of the fire extinguishing conduit.

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

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

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

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

[0017] The diameter of the injection hole may correspond to an angle of about 30° to about 90° around the center of the fire extinguishing conduit.

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

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

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

[0021] The fire extinguishing system may further include: a temperature sensor configured to detect the temperature of one of the plurality of battery cells; a smoke sensor configured to detect the amount of smoke from one of the plurality of battery cells; a controller configured to receive temperature information about one of the plurality of battery cells from the temperature sensor or smoke information about one of the plurality of battery cells from the smoke sensor; and a valve between the fire extinguishing conduit and the 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.

[0022] The fire extinguishing conduit may include aluminum, copper, or stainless steel, wherein the thermosensitive member includes acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), or perfluoroalkoxy olefin (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 described below. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0028] Figure 4A and Figure 4B show a perspective view and a side view respectively illustrating a vehicle body and a vehicle;

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

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

[0031] Figure 7A side view showing a direct injection battery pack fire extinguishing system according to the present disclosure;

[0032] Figure 8A and Figure 8B A diagram showing the operation of a direct injection battery pack fire extinguishing system according to the present disclosure;

[0033] Figure 9A 、 Figure 9B and Figure 9C A plan view and a cross-sectional view showing a fire extinguishing conduit and a heat-sensitive member in a direct injection battery pack fire extinguishing system according to the present disclosure, respectively; and

[0034] Figure 10 A block diagram showing the electrical configuration of a direct injection battery pack fire extinguishing system according to the present disclosure. Detailed Description of the Invention

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Terms or words used in this specification and claims should not be construed restrictively as their ordinary or dictionary meanings, and should be interpreted in a manner consistent with the technical idea of the present disclosure based on the principle that the inventor can appropriately define the concept of terms as his / her own lexicographer to best describe his / her invention.

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

[0037] It will be understood that when an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on, directly connected to, or directly coupled to the other element or layer, or there may also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. 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, for clarity of illustration, the dimensions of various elements, layers, etc. may be exaggerated. The same reference numerals refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Additionally, when describing embodiments of the present disclosure, the use of "may" pertains to "one or more embodiments of the present disclosure". Expressions such as "at least one of..." and "any of..." when following a list of elements modify the entire list of elements and not individual elements in the list. When phrases such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from among A, B, and C" are used to indicate a list of elements A, B, and C, the phrase can refer to any one of A, B, and C and all suitable combinations or subsets thereof, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term "use" may be considered synonymous with the term "utilize". As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent variability of measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0039] It will be understood that although the terms first, second, third, etc. may 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, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section.

[0040] For ease of description, spatial relative terms (such as "beneath", "below", "under", "above", "on", etc.) may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "beneath" other elements or features will then be oriented "above" or "on" the other elements or features. Thus, the term "below" can encompass both an upper and a lower orientation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0041] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular form "a" is intended to also include the plural form, unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the 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] In addition, any numerical range disclosed and / or recited herein is intended to include all sub-ranges of the same numerical precision that are included within the recited range. For example, a range of "1.0 to 10.0" is intended to include all sub-ranges between the recited minimum value of 1.0 and the recited maximum value of 10.0 (and including the recited minimum value of 1.0 and the recited maximum value of 10.0), i.e., all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0 (e.g., such as 2.4 to 7.6). Any maximum numerical limitation recited herein is intended to include all lower numerical limitations contained therein, and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations contained therein. Accordingly, the applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-ranges that are included within the ranges expressly recited herein.

[0043] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same." Thus, the phrase "substantially the same" may include cases having 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 may mean that it is uniform in terms of the average value.

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

[0045] Disposing any element "above (or below)" or "on (or under)" another element may mean that the any element may be positioned in contact with the upper surface (or lower surface) of the element, and another element may also be interposed between the element and any 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, these components may be directly "linked," "coupled," or "connected" to each other, or other components may be "interposed" between these components.

[0047] Throughout the specification, unless otherwise stated, when stating "A and / or B", it means A, B, or both A and B. That is, "and / or" includes any one or all combinations of the listed multiple items. Unless otherwise specified, when stating "C to D", it means C or more and D or less.

[0048] A battery pack according to one or more embodiments includes at least one battery module and a pack housing having an accommodation space for accommodating at least one battery module therein.

[0049] The battery module may include a plurality of battery cells and a module housing. The battery cells may be accommodated inside the module housing in a stacked form (or stacked arrangement or configuration). Each battery cell may have a positive electrode terminal and a negative electrode terminal, and may be circular, prismatic, or pouch-shaped depending on the shape of the battery. In this specification, a battery cell may also be referred to as a secondary battery, a battery, or a cell.

[0050] In the battery pack, one cell stack may constitute one module in place of a battery module stack. The cell stack may be accommodated in the accommodation space of the pack housing, or may be accommodated in an accommodation space separated by a frame, a partition wall, etc.

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

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

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

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

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

[0056] The control device can control the charge / discharge operation and protection operation of the battery. For this purpose, 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 the battery state and performs diagnostic, control, communication, and protection functions, and can calculate the charge / discharge state, calculate the battery life or state of health (SOH), cut off the battery power supply (e.g., relay control) when necessary, control thermal management (e.g., cooling, heating, etc.), perform a high-voltage interlock function, and / or can detect and / or calculate insulation and short-circuit conditions.

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

[0059] Relay control has the function of cutting off the 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 a pre-charge relay at the positive electrode terminal and the negative electrode terminal, respectively.

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

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

[0062] Figure 1A To illustrate a perspective view of a secondary battery according to one or more embodiments of the present disclosure, and Figure 1B For along Figure 1A The cross-sectional view taken along line 1b-1b in. Refer to Figure 1A And Figure 1B According to one or more embodiments of the present disclosure, the secondary battery 100 may include at least one electrode assembly 110 wound in a case where a separator 113 as an insulator is between a positive electrode 111 and a negative electrode 112, a case 120 that receives (or houses) the electrode assembly 110, and a cover assembly 130 coupled to an opening of the case 120.

[0063] Figure 1A And Figure 1B The secondary battery 100 illustrated in and according to one or more embodiments will now be described as an example of a prismatic lithium-ion secondary battery. However, the present disclosure is not limited thereto, and the 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 may 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 that is not coated with the active material.

[0065] The positive electrode 111 and the negative electrode 112 may 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 may have a structure in which the positive electrode 111 and the negative electrode 112 each made of a plurality of sheets are alternately stacked with the separator interposed therebetween.

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

[0067] The cover assembly 130 may include a cover plate 131 that covers an opening in the housing 120, and the housing 120 and the cover plate 131 may be made of a conductive material. A positive electrode terminal 121 and a negative electrode terminal 122 that are electrically connected to the positive electrode 111 and the negative electrode 112, respectively, may be installed to penetrate (or extend through) the cover plate 131 and protrude outward through it.

[0068] The outer circumferential surface (e.g., circumferential surface) of the upper columns of the positive electrode terminal 121 and the negative electrode terminal 122 that protrude outward from the cover plate 131 may be threaded and may be fixed to the cover plate 131 by using nuts.

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

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

[0071] The positive electrode terminal 121 and the negative electrode terminal 122 may be electrically connected to the uncoated portion 111a of the positive electrode and the uncoated portion 112a of the negative electrode by being respectively coupled or joined (e.g., by welding) to a current collector including a first current collector 140 and a second current collector 150 (hereinafter referred to as a positive electrode current collector and a negative electrode current collector).

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

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

[0074] According to one or more embodiments of the present disclosure, one end of the separation member may face one side of the electrode assembly 110 and may be mounted 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 may include a first separation member 180 and a second separation member 190.

[0076] In such an embodiment, the first ends of the first separation member 180 and the second separation member 190, which are mounted to face one side of the electrode assembly 110, may be respectively mounted 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.

[0077] The positive electrode terminal 121 and the negative electrode terminal 122, which can be connected to the positive electrode current collector 140 and the negative electrode current collector 150 by welding, may be connected to the first lower insulating member 160 and the second lower insulating member 170 and the first ends of the first separation member 180 and the second separation member 190.

[0078] Figure 2 FIG. is a perspective view of a battery module illustrating one or more embodiments of the present disclosure. Refer to Figure 2 , a battery module 200 according to one or more embodiments of the present 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 may include a battery management system (BMS). Further, the connection tab 220 may 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 may be, for example, a bus bar.

[0079] Each battery cell 100 may include a battery case, an electrode assembly received (or accommodated) 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. An electrode terminal 121 and 122 electrically connected to a connection tab 220 and an exhaust portion 134 serving as a discharge passage for gas generated inside the battery case may be provided on one side (e.g., the upper side) of the battery cell 100. The electrode terminals 121 and 122 of the battery cell 100 may 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 may be electrically connected in series or in parallel to each other through the connection tab 220, which will be described in more detail below. Although the series connection has been described as an example, the connection structure is not limited thereto, and various connection structures may be adopted according to expectations or needs. The number and arrangement of the battery cells are not limited to Figure 2 the structure shown in

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

[0081] The protection circuit module 230 may have electronic components and a protection circuit mounted thereon and may be electrically connected to the connection tab 220, which will be described in more detail later. The protection circuit module 230 includes a first protection circuit module 230a and a second protection circuit module 230b that extend in a direction along which a plurality of battery cells 100 are arranged at different positions. The first protection circuit module 230a and the second protection circuit module 230b may be spaced apart from each other by a suitable spacing (e.g., a predetermined spacing) and arranged parallel to each other to be electrically connected to adjacent connection tabs 220, respectively. For example, the first protection circuit module 230a extends in a direction along which the plurality of battery cells 100 are arranged on one side of the upper portion of the plurality of battery cells 100, and the second protection circuit module 230b extends in a direction along which the plurality of battery cells 100 are arranged on the other side of the upper portion of the plurality of battery cells 100. The second protection circuit module 230b may be spaced apart from the first protection circuit module 230a by a suitable spacing (e.g., a predetermined spacing) with the exhaust portion 134 therebetween, but may be positioned parallel to the first protection circuit module 230a. Thus, the two protection circuit modules are spaced apart from each other side by side in a direction along which the plurality of battery cells 100 are arranged, thereby reducing or minimizing the area of the printed circuit board (PCB) constituting the protection circuit module. By separately configuring the protection circuit module into 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 may 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, such that the two protection circuit modules 230a and 230b can be electrically connected to each other.

[0082] The connection may 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 may be, for example, a wire. The connection member 250 may be made of a material having elasticity or flexibility. Through the connection member 250, it may 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 tab 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 tab adjacent to the second protection circuit module may be integrated and managed by the protection circuit module through the connection member 250.

[0084] When the battery cell 100 expands, the impact can be absorbed due to the elasticity or flexibility of the connection member 250, thereby preventing damage to the first protection circuit module 230a and the second protection circuit module 230b.

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

[0086] As described above, since the protection circuit module 230 is provided as the first protection circuit module 230a and the second protection circuit module 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 ensured, which improves work efficiency by facilitating the fastening work for connecting the connection tab 220 and the protection circuit module 230 and facilitating the repair work if an abnormality is detected in the battery module (or when an abnormality is detected in the battery module).

[0087] Figure 3A and Figure 3B FIG. shows a battery pack 300 according to one or more embodiments of the present disclosure. The battery pack 300 may include a plurality of battery modules 200 and a housing 310 for accommodating the plurality of battery modules 200. For example, the housing 310 may 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 may be electrically connected to each other by using a bus bar 251, and the plurality of battery modules 200 may be electrically connected to each other in a series / parallel or series-parallel hybrid method to obtain a desired (e.g., required) electrical output.

[0088] Figure 4A and Figure 4B FIGS. respectively show a vehicle body 400 and a vehicle 500 including the Figure 3A and Figure 3B battery pack 300 shown in. In Figure 4A FIG., the battery pack 300 may include a battery pack cover 311' and a group frame 312', the battery pack cover 311' being a part of the vehicle bottom 410 and corresponding to the first housing 311, and the group frame 312' being located below the vehicle bottom 410 and corresponding to the second housing 312. The battery pack cover 311' and the group frame 312' may be integrally formed with the vehicle floor plate 420 of the vehicle. The vehicle bottom 410 separates the interior and exterior of the vehicle, and the group frame 312' may be located outside the vehicle.

[0089] In Figure 4BIn [description], the vehicle 500 can be formed by combining additional parts (such as the hood 510 in front of the vehicle 500 and the bumpers 520 located in front of and behind the vehicle 500 respectively) with the vehicle body 400. The vehicle 500 can include a battery pack 300, the battery pack 300 includes a battery pack cover 311' and a pack frame 312', and the battery pack 300 can be coupled to the vehicle body 400.

[0090] Figures 5A to 5B The schematic diagram showing an exemplary charging method for a secondary battery is illustrated. 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 the voltage reaches a suitable voltage or reference voltage (e.g., a predetermined voltage) and then performs constant voltage (CV) charging until the flowing current amount decreases, for example, until a final current value is achieved.

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

[0093] When (or if) the secondary battery voltage V B reaches a suitable voltage or reference voltage (e.g., a predetermined voltage) (e.g., approximately 4.3V), the CC charging switches to CV charging. During CV charging, as Figure 5B shown, the switch of the constant voltage power supply is turned on and the switch of the constant current power supply 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 with time. Since V B = V R + V C , the voltage V R applied to the internal resistance R decreases with time. As the voltage V R applied to the internal resistance R decreases, according to Ohm's law (V R = R×I), the current I flowing through the secondary battery can also decrease.

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

[0095] Figure 5D shows a graph of the secondary battery voltage V B and the charging current during and after the termination of CCCV charging. Even after the termination of CCCV charging, the secondary battery voltage V B basically does not 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 with each other to provide a high energy density. According to an appropriate amount of power, the battery module can be formed by interconnecting the electrode terminals of a plurality of battery cells to achieve a high-output secondary battery. A structure in which a plurality of battery modules are connected in series and / or in parallel with 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 connected to a common current collector 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 the interchangeability of components. To implement 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 set 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 fixing of the battery cell or sub-module can be achieved by recessed portions or mechanical interconnecting members (such as bolts or screws) formed in the cooling plate. In one or more embodiments, the battery cell or sub-module can be constrained by fastening side plates to the side surfaces of the cooling plate.

[0099] To provide thermal control of a battery pack, a thermal management system may be adapted to safely use at least one battery module by effectively radiating, releasing, and / or dissipating heat generated by a secondary battery. If heat is not sufficiently radiated / released / dissipated, a temperature deviation may occur between battery cells, such that at least one battery module may not generate a desired amount of power. An increase in internal temperature may cause abnormal reactions to occur therein, potentially resulting in deterioration of the charge / discharge 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 a cell.

[0100] Thermal runaway is an example of an abnormal operating state of a battery cell that may occur due to a severely overheated or overcharged lithium-ion battery cell. The critical temperature at which thermal runaway occurs may be about 150 °C or higher, and heat may propagate from a battery cell with a defective electrical contact or short circuit to another adjacent battery cell. 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 exhausted. During thermal runaway, a defective cell can be heated to a cell temperature of about 800 °C or higher, and a large amount of hot gas can be discharged into the interior of the system. A battery cell typically may include an exhaust hole formed therein to discharge exhaust if the pressure in the battery cell exceeds a reference pressure. In a cell housing with a high energy density (e.g., about 200 Wh / kg), the discharged exhaust may 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 be propagated to adjacent cells due to the exhaust. Since these cells are heated by the faulty cell due to heat conduction via its side plate, base plate, and / or electrical connector, the cells are likely to experience thermal runaway. This can lead to thermal runaway propagation and a battery fire in the entire battery system.

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

[0103] Recently, a direct injection fire extinguishing system has been adopted, in which if an event occurs in a certain battery cell, a fire extinguishing conduit is opened, and the opening of the exhaust part of the battery cell is detected, such that a fire extinguishing agent is directly injected into the interior / exterior of the battery cell where the event occurs. Such a direct injection fire extinguishing system may be adapted to the trend towards higher capacity battery cells.

[0104] In one or more embodiments, a direct injection fire extinguishing system may perform a method of extinguishing a fire in response to flames and / or smoke from a battery cell when an event occurs in the cell. In one or more embodiments, flames emitted from the exhaust portion of the cell may melt the polymer resin of the agent injection nozzle that blocks the fire extinguishing conduit, and a temperature sensor or a smoke sensor may detect the temperature or may detect the amount of smoke, and may send an opening signal to the fire extinguishing agent supplier, so that the fire extinguishing agent may be directly injected through the opened nozzle of the fire extinguishing conduit into the cell where the event occurs.

[0105] In one or more embodiments, the fire extinguishing conduit of the direct injection fire extinguishing system may be processed in such a way that a through hole serving as a nozzle is formed in the fire extinguishing conduit. The through hole in the fire extinguishing conduit may be blocked by a polymer material through a separate insert injection molding process. The polymer injection molding portion may block the through hole in a normal state to seal the fire extinguishing conduit. When an event occurs in the cell, the polymer injection molding portion may be melted by the flame, and then the nozzle may be opened by the pressure of the injected fire extinguishing agent, so that the fire extinguishing agent may reach the cell where the event occurs. Thus, when an event occurs, the opening of the nozzle may depend on the temperature of the flame and / or may depend on the time of exposure to the flame.

[0106] When an event occurs in a cell at the beginning of its life (e.g., a cell with a 100% state of charge), the temperature of the flame directly emitted from the cell may be about 800 °C or higher, and there may be no problem in opening the nozzle located above the exhaust portion. When an event occurs in a cell at the end of its life, or in a structure where it is difficult or impossible to directly place the fire extinguishing conduit above the exhaust portion (e.g., via a heat transfer medium), the temperature transmitted 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 an appropriate time, potentially resulting in fire extinguishing failure.

[0107] It is desirable to develop a direct injection fire extinguishing system that can stably open the nozzle even at a temperature below about 800 °C. In the present disclosure, a temperature below about 800 °C may be defined as a low temperature.

[0108] Figure 6 To show a schematic diagram of a direct injection battery pack fire extinguishing system 600 according to the present disclosure. As Figure 6 shown, in one or more embodiments, the direct injection battery pack fire extinguishing system 600 may include a fire extinguishing agent supplier 610 configured to supply a fire extinguishing agent to the battery pack 300 or the battery module 200, a fire extinguishing conduit 620 configured to convey and inject the fire extinguishing agent, and a sensor configured to detect a fire. In one or more embodiments, the battery pack 300 or the battery module 200 may include or may be referred to as an energy storage system.

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

[0110] The fire extinguishing agent injection container 611 may be a pressure vessel for storing the fire extinguishing agent. Depending on whether the fire extinguishing agent injection container 611 can be independently installed, the fire extinguishing agent injection container 611 may be classified as a self-supporting type or a support structure attachment type. In one or more embodiments, the fire extinguishing agent may include Novec TM 1230 (Novec TM is a registered trademark of 3M Company in Delaware, USA). The compressed gas for injecting the fire extinguishing agent may include nitrogen.

[0111] If the controller decides to inject the fire extinguishing agent, the exhaust valve 612 may be opened so that the fire extinguishing agent is injected. The exhaust valve 612 may be used to open or close the fire extinguishing agent injection container 611. If the exhaust valve 612 is opened, the fire extinguishing agent may be discharged and move to the regulator 613. The regulator 613 may be used to adjust the injection pressure of the fire extinguishing agent to the final injection pressure. To this end, the regulator 613 may include a pressure regulator.

[0112] The fire extinguishing conduit 620 may include a main pipe, branch pipes, and injection pipes that extend from the fire extinguishing agent supplier 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 injection pipes for injecting the fire extinguishing agent may be mounted to each battery rack.

[0113] If a fire occurs in the battery module 200, the sensor may detect the occurrence of the fire, and the fire extinguishing agent may be supplied from the fire extinguishing agent supplier 610 and sprayed through the fire extinguishing conduit 620 onto the battery module 200. The fire extinguishing agent may be quickly sprayed onto the battery module 200, thereby extinguishing the fire that has occurred in the battery module 200.

[0114] Hereinafter, for convenience of description, the main pipe, branch pipes, and injection pipes will be collectively referred to as the fire extinguishing conduit 620, and the fire extinguishing conduit 620 and the thermosensitive member 630 coupled thereto will be mainly described.

[0115] Figure 7 To show a side view of the direct injection type battery pack fire extinguishing system 600 according to the present disclosure. In Figure 7In the example shown, the battery module 200 may include a plurality of battery cells 100 arranged in alignment with each other in a first direction (e.g., the Y direction). In one or more embodiments, each battery cell 100 may be a prismatic (or rectangular) cell, and the wide flat sidewalls 124, 125 of the battery cells 100 may be stacked together to form the battery module 200. In one or more embodiments, the battery cells 100 may be arranged such that the sidewalls 124, 125 of adjacent battery cells 100 face each other 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 transfer may be located between the sidewalls 124, 125 of adjacent battery cells 100. In one or more embodiments, the positive electrode terminals and the negative electrode terminals of adjacent battery cells 100 may be electrically connected to each other through bus bars. The plurality of battery cells 100 may 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 may be electrically connected to each other to form a battery pack 300, and the battery pack 300 may be used as a power source.

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

[0117] The direct injection type battery pack fire extinguishing system 600 may include the above-described fire extinguishing conduit 620 and a plurality of thermal members 630. The fire extinguishing conduit 620 may include injection holes 621 formed therein to inject a fire extinguishing agent into 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 may be blocked by a plug 622. The thermal member 630 may be coupled to the fire extinguishing conduit 620 while blocking the injection holes 621. In one or more embodiments, the number of injection holes 621 formed in the fire extinguishing conduit 620 may 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 (e.g., two injection holes 622) may correspond to each exhaust portion 134. In one or more embodiments, each thermal member 630 may include a body portion 631 surrounding (e.g., 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 holes 621 and having a thickness smaller than the thickness of the body portion 631.

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

[0119] In one or more embodiments, the battery modules 200 may be spaced apart along a second direction (e.g., the X direction). The above-described fire extinguishing conduit 620 and the above-described thermal members 630 may also be spaced apart along the second direction above the battery modules 200. In one or more embodiments, the plurality of battery modules 200 may be referred to as a battery pack 300.

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

[0121] Figure 9A 、 Figure 9B and Figure 9C are a plan view and a cross-sectional view showing the fire extinguishing conduit 620 and the heat-sensitive member 630 in the direct-injection battery pack fire extinguishing system 600 according to the present disclosure, respectively, where Figure 9B and Figure 9C are cross-sectional views taken along the line 9b-9b in Figure 9A . For ease of description, the fire extinguishing conduit 620 and the heat-sensitive member 630 are shown in an inverted state. As shown in Figure 9A and Figure 9B , the direct-injection battery pack fire extinguishing system 600 may include a fire extinguishing conduit 620 and a heat-sensitive member 630. In one or more embodiments, the fire extinguishing conduit 620 may include a conductive material (such as aluminum, copper, or stainless steel), and the heat-sensitive member 630 may include a polymer (such as acrylonitrile-butadiene-styrene (ABS), polypropylene (PP), polycarbonate (PC), polyethylene (PE), or perfluoroalkoxy olefin (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 one heat-sensitive member 630. In one or more embodiments, the heat-sensitive member 630 may include a main body portion 631 surrounding the outer periphery of the fire extinguishing conduit 620, and may further include a nozzle portion 632 located in the region corresponding to the injection holes 621 and having a thickness smaller than that of the main body portion 631. In one or more embodiments, the nozzle portion 632 may include two recessed portions 6321 formed in the main body portion 631 and recessed toward the two injection holes 621, and may further include two thin film portions 6322 respectively formed at the bottoms of the two recessed portions 6321 and having a thickness smaller than that of the main body portion 631. A rib 6324 having a relatively large thickness may be formed between the two recessed portions 6321. The rib 6324 may be used to reduce or prevent the possibility of the region between the two thin film portions 6322 melting before the two thin film portions 6322 melt.

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

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

[0125] In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 may be greater than the thickness of the film portion 6322. In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 may be about 1.5 times to about 3 times the thickness of the film portion 6322. In one or more embodiments, the thickness of the inner wall 6323 of the recessed portion 6321 may be about 0.15 mm to about 1.5 mm. The thermal sensitive member 630 may be formed on the fire extinguishing conduit 620 by a double injection molding process. Due to the design tolerance of the injection mold, it may be difficult to make the thickness of the inner wall 6323 of the recessed portion 6321 less than about 0.15 mm. If the thickness of the inner wall 6323 of the recessed portion 6321 is greater than about 1.5 mm, the area of the film portion 6322 may be reduced, and the efficiency of the injection of the fire extinguishing agent may be reduced.

[0126] In one or more embodiments, the thickness of the film portion 6322 may be about 0.1 mm to about 0.5 mm. If the thickness of the film portion 6322 is less than about 0.1 mm, the film portion 6322 may be more easily damaged by external impact. If the thickness of the film portion 6322 is greater than about 0.5 mm, it may take a relatively long time for the film portion 6323 to melt, which may reduce the efficiency of fire extinguishing.

[0127] In one or more embodiments, the diameter of the injection hole 621 may correspond to an angle θ of about 30° to about 90° around 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 may also correspond to an angle θ of about 30° to about 90° around the center of the diameter of the fire extinguishing conduit 620. If the diameter range of the injection hole 621 is less than about 30°, the heat transfer efficiency through the exhaust gas may be reduced, and the film portion 6322 may not be melted at the desired time. If the diameter range of the injection hole 621 is greater than about 90°, the durability of the film portion 6322 may be reduced, and the film portion 632 may be damaged by external impact.

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

[0129] In one or more embodiments, the thin film portion 6322 may melt at a temperature in the range of about 150 °C to about 500 °C. In one or more embodiments, the thermosensitive member 630 may melt at a temperature in the range of about 150 °C to about 500 °C. Since the thickness of the thin film portion 6322 is less than the thickness of the main body portion 631, the thin film portion 6322 may open relatively quickly. In one or more embodiments, the recessed portion 6321 and the thin film portion 6322 may be provided corresponding to the exhaust portion 134 of the battery cell 100, such that the thin film portion 6322 may 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 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 thermosensitive member 630 and the fire extinguishing conduit 620, which causes the melting of the thermosensitive member 630. A part of the heat suitable for melting the thermosensitive member 630 can be transferred to the fire extinguishing conduit 620, and a relatively large amount of heat can appropriately open the nozzle portion 632.

[0131] If the heat transferred to the fire extinguishing conduit 620 is reduced or minimized, the thermosensitive member 630 can melt quickly or at a low temperature. According to the present disclosure, the 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 Figure 9B FIG., the three thick arrows represent the heat transfer paths created by the exhaust gas traveling to the thin film portion, and the two dashed arrows on both sides represent the heat transfer paths created by the exhaust gas traveling to the fire extinguishing conduit. As Figure 9B shown in FIG., the heat transferred to the thin film portion can be greater than the heat transferred to the fire extinguishing conduit.

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

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

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

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

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

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

[0138] In one or more embodiments, when it is determined that the temperature of the battery cell 100 exceeds a reference value and / or the amount of smoke from the battery cell 100 exceeds a reference value, the controller 643 may send a control signal for opening the valve 612 to the valve 612. The fire extinguishing agent may be completely ejected from the fire extinguishing agent injection container 611 through the fire extinguishing conduit 620 and the heat-sensitive member 630 to the battery cell 100.

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

[0140] As is apparent from the above description, the present disclosure may 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 adjacent battery cells, and reducing or preventing heat transfer to another battery cell adjacent to the corresponding battery cell.

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

Claims

1. An extinguishing system for a plurality of battery cells, the extinguishing system comprising: An extinguishing conduit defining an ejection hole for ejecting a fire extinguishing agent into an exhaust hole of one of the plurality of battery cells; And A thermosensitive member blocking the ejection hole and comprising: A main body portion at least partially surrounding an outer periphery of the extinguishing conduit; And A nozzle portion corresponding to the ejection hole and having a thickness smaller than a thickness of the main body portion.

2. The extinguishing system according to claim 1, wherein the nozzle portion comprises: A recessed portion in the main body portion and recessed toward the ejection hole; And A thin film portion at a bottom of the recessed portion and having a thickness smaller than the thickness of the main body portion.

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

4. The extinguishing system according to claim 2, wherein a diameter of the recessed portion is smaller than a diameter of the ejection hole.

5. The extinguishing system according to any one of claims 1 to 4, wherein a diameter of the ejection hole is 6% to 30% of an arc length of a cross-section of the extinguishing conduit.

6. The extinguishing system according to any one of claims 2 to 4, wherein the recessed portion comprises an inner wall having a thickness larger than the thickness of the thin film portion.

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

8. The extinguishing system according to any one of claims 2 to 4, wherein the recessed portion comprises an inner wall having a thickness of 0.15 mm to 1.5 mm.

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

10. The extinguishing system according to any one of claims 1 to 4, wherein a diameter of the ejection hole corresponds to an angle of 30° to 90° around a center of the extinguishing conduit.

11. The extinguishing system according to any one of claims 2 to 4, wherein the recessed portion comprises an inner wall having a height of 0.5 mm to 3 mm.

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

13. The extinguishing system according to any one of claims 2 to 4, wherein the thin film portion is configured to be melted by exhaust gas discharged from the exhaust hole of one of the plurality of battery cells.

14. The extinguishing system according to any one of claims 1 to 4, further comprising: A temperature sensor configured to detect a temperature of one of the plurality of battery cells; A smoke sensor configured to detect the amount of smoke from one of the plurality of battery cells; A controller configured to receive temperature information about one of the plurality of battery cells from the temperature sensor or smoke information about one of the plurality of battery cells from the smoke sensor; And A valve between the fire extinguishing conduit and the 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 determining 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, wherein the fire extinguishing conduit comprises aluminum, copper or stainless steel, and wherein the thermosensitive member comprises acrylonitrile-butadiene-styrene, polypropylene, polycarbonate, polyethylene or perfluoroalkoxy olefin.

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