Fire extinguishing composition and battery pack comprising same

Abstract

The invention relates to a fire extinguishing composition and a battery pack comprising the same. The fire extinguishing composition contains an inorganic compound and a polycarboxylic acid compound at a predetermined content ratio, and the viscosity at room temperature is controlled within a predetermined range, thereby being capable of uniformly forming a fire extinguishing film at the point at which an event occurs when a thermal event occurs in a battery pack, and thus having characteristics of a high cooling effect and a suffocation effect for fire extinguishing. Further, the battery pack including the fire extinguishing composition can quickly detect a point at which a thermal event occurs and concentratedly spray the fire extinguishing composition to the corresponding point, thereby not only facilitating prevention of the propagation of the thermal event, but also having the advantage of shortening the time required to solve the event.

Description

TECHNICAL FIELD

[0001] The present application relates to a fire extinguishing composition and a battery pack including the same.

[0002] This application claims the priority benefit of Korean Patent Application No. 10-2024-0042899, filed on March 29, 2024, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND

[0003] Secondary batteries are characterized by being capable of repeated charge and discharge, and are receiving much attention in various fields ranging from small mobile devices to electric vehicles, hybrid vehicles, or energy storage systems (ESS). In addition, applications using secondary batteries are becoming more diverse, and various types of batteries are also being developed to provide appropriate output and capacity.

[0004] Secondary batteries applied to electric vehicles or energy storage systems are used as so-called middle-large battery packs in which a plurality of battery cells are electrically connected due to the demand for high output and large capacity.

[0005] Middle-large battery packs have a configuration in which a plurality of battery modules are accommodated in a case and electrically connected, and are equipped with various safety and control devices to prevent fire or explosion due to overcharge, overdischarge, overcurrent, heat generation, and chain reaction during use. The control device continuously detects the voltage, current, temperature, etc. of the battery cell and controls the operation of the battery. However, even when the control device is used, electrical faults can occur at any time due to physical impact or vibration applied due to external or internal problems. It is known that the probability of fire and explosion due to electrical faults of a battery pack is high.

[0006] A fire occurring in a battery pack starts from abnormal temperature rise and internal gas generation of a lithium secondary battery provided inside a battery module. When the temperature of the lithium secondary battery abnormally rises and the internal pressure of the lithium secondary battery rises above a certain level due to internal gas generation, venting occurs in the lithium secondary battery. As a result, high-temperature gas is discharged to the outside of the lithium secondary battery, and high-temperature sparks containing electrode active materials and aluminum particles are emitted. When such high-temperature gas and sparks meet oxygen, a fire can occur.

[0007] In the case where a thermal event such as abnormal high temperature, gas discharge, spark emission, or fire occurrence occurs in some of the plurality of battery modules included in the battery pack, if appropriate measures are not taken, the thermal event can spread to adjacent battery modules.

[0008] Therefore, there is a need to develop a battery pack capable of effectively preventing and resolving the spread of a thermal event occurring within the battery pack. SUMMARY

[0009] Technical problem

[0010] Therefore, an object of the present application is to provide a technology capable of effectively solving a thermal event that occurs while preventing the spread when a thermal event occurs in a device such as a battery pack including a plurality of battery cells.

[0011] Technical solution

[0012] To solve the above problem, the present application provides a fire extinguishing composition having a form in which 100 parts by weight of an inorganic compound represented by the following Chemical Formula 1 and 0.01 to 5 parts by weight of a polycarboxylic acid compound are mixed in water, and

[0013] characterized in that the fire extinguishing composition has a viscosity in the range of 2,000 to 10,000 mPa·s at 25±3℃: [Chemical Formula 1] M p O q (OH) r In Chemical Formula 1, wherein M is magnesium or aluminum, wherein p is an integer of 1 to 10, q is an integer of 0 to 20, with the proviso that p≤q, wherein r is an integer of 1 to 5.

[0014] The fire extinguishing composition contains the inorganic compound represented by Chemical Formula 1 and the polycarboxylic acid compound in a predetermined content ratio to delay ignition or extinguish a fire when a thermal event occurs in a battery pack.

[0015] The inorganic compound represented by Chemical Formula 1 can include one or more of boehmite, pseudoboehmite, diaspore, akdalaite, aluminum hydroxide, and magnesium hydroxide.

[0016] The polycarboxylic acid compound can include one or more of malonic acid, citric acid, malic acid, oxalic acid, glutamic acid, aspartic acid, an amino acid, a fatty acid, methane tricarboxylic acid, ethane tricarboxylic acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzene tricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid, benzene-1,2,3,4,5-pentacarboxylic acid, and benzene-1,2,3,4,5,6-hexacarboxylic acid.

[0017] Further, the fire extinguishing composition can further include one or more pH control agents selected from the group consisting of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, monobasic ammonium phosphate, dibasic ammonium phosphate, ammonium phosphate, ammonium chloride, ammonium molybdate, ammonium bromate, ammonium acetate, ammonium nitrate, and ammonium sulfate.

[0018] The pH control agent can be included in an amount such that the pH of the fire extinguishing composition becomes 5 to 7.5.

[0019] Further, the fire extinguishing composition can further include one or more viscosity adjusting agents selected from the group consisting of sodium alginate, pectin, gelatin, a high-molecular polysaccharide, a cellulose compound, a nonionic surfactant, bentonite, and a borate.

[0020] The fire extinguishing composition according to the present application can have a viscosity in the range of 2,000 mPa·s to 10,000 mPa·s at 25±3℃.

[0021] For example, the fire extinguishing composition can have a viscosity in the range of 2,000 mPa·s or more and less than 5,000 mPa·s at 25±3℃, and can have a viscosity in the range of 5,000 mPa·s or more and less than 9,000 mPa·s at 25±3℃.

[0022] The fire extinguishing composition can have a solid content in the range of 10 wt% to 90 wt%.

[0023] Further, the present application provides a battery pack including a battery assembly including a plurality of battery cells arranged in a first direction, and a packaging case in which the battery assembly is accommodated, wherein the packaging case includes a fire extinguishing portion provided on at least one inner surface of a top surface and a side surface to spray the above-mentioned fire extinguishing composition according to the present application when a thermal event occurs.

[0024] Here, the thermal event can include one or more of a temperature rise of 100℃ or more, gas discharge, flame ejection, and fire occurrence.

[0025] Further, the battery assembly can include a sensing portion including one or more detection sensors selected from the group consisting of: a plurality of temperature detection sensors mounted on the battery assembly to detect a surface temperature of the battery assembly; a gas detection sensor to detect concentrations of carbon monoxide, carbon dioxide, and ethane contained in internal air of the battery pack; and a flame detection sensor to detect whether a flame occurs and a position where the flame occurs.

[0026] Further, the battery pack can further include a control unit electrically connected to the sensing portion and the fire extinguishing portion to obtain information detected by the detection sensor of the sensing portion during a thermal event, determine whether a thermal event occurs and a location of occurrence from the obtained information, and move the fire extinguishing portion to the corresponding location of occurrence.

[0027] Further, the fire extinguishing portion can include: a fire extinguishing agent storage portion located outside the package case and storing a fire extinguishing composition; a gas storage portion located outside the package case and storing an inert gas; a spraying device receiving and spraying the fire extinguishing composition and the inert gas stored in the fire extinguishing agent storage portion and the gas storage portion, respectively, and capable of rotating 180° along a direction perpendicular to the first direction; and a guide portion located on an inner surface of the package case to move the spraying device along the first direction of the battery assembly.

[0028] Here, the spraying device can include: a slurry supply pipe fluidly connected to the fire extinguishing agent storage portion to supply the fire extinguishing composition stored in the fire extinguishing agent storage portion; a gas supply pipe fluidly connected to the gas storage portion to supply the inert gas stored in the gas storage portion; a spraying main body fluidly connected to the slurry supply pipe and the gas supply pipe to provide a space in which the fire extinguishing composition and the inert gas supplied from them are mixed; and a nozzle fastened to an end portion of the spraying main body to spray a mixture of the fire extinguishing composition and the inert gas.

[0029] The gas supply pipe can further include a compression pump applying pressure to the inert gas, and the nozzle can have a flow rate controlled by the pressure of the inert gas supplied from the gas supply pipe.

[0030] Further, the spraying main body can be provided with: a rotating device including a motor configured to generate a driving force for rotation along a direction perpendicular to the first direction and a gear interposed between the motor and the spraying main body; and a fixing device located between the rotating device and the guide portion to move the spraying main body by the guide portion.

[0031] Advantageous Effects

[0032] The fire extinguishing composition according to the present application includes an inorganic compound and a polycarboxylic acid compound in a predetermined content ratio and controls a viscosity at room temperature in a predetermined range, thereby being capable of uniformly forming a fire extinguishing film at a point where a thermal event occurs when the thermal event occurs in a battery pack, and thus having characteristics of a high cooling effect and a smothering effect for fire extinguishing.

[0033] In addition, the battery pack including the fire extinguishing composition is capable of quickly detecting a point at which a thermal event occurs and spraying the fire extinguishing composition to the corresponding point, thereby not only being advantageous in preventing the thermal event from spreading, but also having an advantage of shortening the time required to solve the event. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural diagram schematically showing the structure of a battery pack and the working principle of a fire extinguishing portion according to the present application.

[0035] Figure 2 is a perspective view showing a fire extinguishing portion according to the present application.

[0036] Figure 3 is a sectional view showing a section in which a spraying device is cut in the Y-axis and Z-axis directions, for showing the structure of a spraying device of a fire extinguishing portion according to the present application.

[0037] Figure 4 is a sectional view showing a section in which a spraying device is cut in the X-axis and Y-axis directions, for showing the structure of a rotating device of a fire extinguishing portion according to the present application. DETAILED DESCRIPTION

[0038] The present application can have various modifications and various embodiments, and a specific embodiment will be described in detail in the following detailed description.

[0039] However, it should be understood that the present application is not limited to the specific embodiments, and includes all modifications, equivalents, or alternatives within the spirit and technical scope of the present application.

[0040] The terms "comprise", "include" and "have" as used herein indicate the presence of the features, numbers, steps, actions, constituent elements, or components described in the specification, and it should be understood that the possibility of presence or addition of one or more other features, numbers, steps, actions, constituent elements, components, or combinations thereof is not precluded.

[0041] In addition, when a part of a layer, film, region, plate, etc. is disposed "on" another part, this includes not only a case in which one part is "directly" disposed "on" another part, but also a case in which there is still another part interposed therebetween. In contrast, when a part of a layer, film, region, plate, etc. is disposed "under" another part, this includes not only a case in which one part is "directly" disposed "under" another part, but also a case in which there is still another part interposed therebetween. In addition, the disposition "on" in the present application can include not only the disposition on the upper portion but also the disposition on the lower portion.

[0042] As used herein, the terms “about,” “approximately,” and “substantially” refer to a range of values ​​or degrees that are close to them, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly exploiting the precise or absolute numerical values ​​provided therein to aid in understanding the disclosure of this invention.

[0043] Furthermore, in this specification, "D" 50 "It can be defined as the particle size corresponding to 50% of the cumulative volume in the particle size distribution curve (the graphical curve of particle size distribution). D" 50 For example, laser diffraction can be used for measurement. Laser diffraction methods are typically capable of measuring particle sizes from the submicron region to a few millimeters, and can obtain results with high reproducibility and high resolution.

[0044] In this specification, "solid content" refers to the percentage by mass of substances other than the solvent (i.e., solids) contained in the extinguishing composition. Solid content can be obtained by first measuring the mass of the extinguishing composition, then measuring the mass of the solvent contained in the extinguishing composition after evaporation, and then calculating the percentage of the second measurement relative to the first measurement.

[0045] In this specification, "viscosity" refers to the viscosity measured using a Brookfield rotational viscometer over a temperature range of 25 ± 3 °C and at a speed of 0.01 s⁻¹. -1 Up to 1,000 s -1 Viscosity measured within the range of shear rates.

[0046] The invention will be described in more detail below.

[0047] Fire extinguishing composition

[0048] The present invention provides a fire extinguishing composition comprising 100 parts by weight of an inorganic compound represented by the following chemical formula 1 and 0.01 to 5 parts by weight of a polycarboxylic acid compound mixed in water, and

[0049] The fire extinguishing composition is characterized in that its viscosity at 25±3°C is in the range of 2,000 mPa·s to 10,000 mPa·s. [Chemical Formula 1] M p O q (OH) r In chemical formula 1, Where M is magnesium or aluminum. Where p is an integer from 1 to 10, q is an integer from 0 to 20, and the condition is p ≤ q. Where r is an integer from 1 to 5.

[0050] The fire extinguishing composition according to the present application is applied to a battery pack including lithium secondary batteries as battery cells, and can be used to extinguish a fire that has already occurred, or can be used to limit an abnormal temperature rise before ignition. The fire extinguishing composition can be sprayed to a point where a thermal event is expected to occur or has already occurred in the battery pack to form a uniform fire extinguishing film on the surface of the corresponding point. Since the fire extinguishing composition can cool the surrounding heat while preventing contact with oxygen in the air during the process of forming the fire extinguishing film, it has excellent fire prevention and fire extinguishing effects.

[0051] Here, the thermal event can refer to one or more of a temperature rise of 100°C or more, gas discharge, flame spitting, and fire occurrence that occur inside a device including a plurality of lithium secondary battery cells.

[0052] To achieve the above effects, the fire extinguishing composition includes an inorganic compound and a polycarboxylic acid compound.

[0053] The inorganic compound is a substance that forms a main component of the fire extinguishing composition, remains in a stable state even at a temperature of about 200°C to 350°C, and has a characteristic of thermally decomposing into water and inorganic oxides at a temperature higher than the above temperature to absorb surrounding heat. In this case, the thermal decomposition can lower the ambient temperature of the inorganic compound to suppress ignition, thereby reducing the likelihood of fire occurrence. In addition, the inorganic compound has the advantage of not only reducing the generation of smoke and toxic gas during fire occurrence but also suppressing ignition even when flames or sparks splash.

[0054] Such an inorganic compound includes a compound represented by the following Chemical Formula 1: [Chemical Formula 1] M p O q (OH) r In Chemical Formula 1, where M is magnesium or aluminum, where p is an integer of 1 to 10, q is an integer of 0 to 20, with the proviso that p ≤ q, where r is an integer of 1 to 5.

[0055] For example, the inorganic compound can include one or more of boehmite, pseudoboehmite, hard water aluminum, bayerite, aluminum hydroxide, and magnesium hydroxide.

[0056] The clay used in the conventional fire extinguishing composition has excellent fire resistance by itself, but is limited in that the fire resistance is reduced due to chemical reactions occurring due to the components constituting the clay and the environment in which the fire extinguishing composition is placed. However, the inorganic compound has excellent chemical resistance and is capable of achieving high fire resistance even when in a composition state for a long time. In addition, the inorganic compound has a relatively high endothermic amount in the temperature range of 200°C to 300°C compared to metal oxides such as alumina, and thus has the effect of delaying the internal temperature of the battery pack from reaching the ignition point when the internal temperature rapidly increases before ignition occurs inside the battery pack.

[0057] In addition, the inorganic compound can have a predetermined particle size. The inorganic compound can have a small average particle diameter to uniformly form a fire extinguishing film on the surface of the spraying point even after the fire extinguishing composition is sprayed in a small amount. For example, the average particle diameter (D 50 ) of the inorganic compound can be in the range of 0.01 μm to 100 μm, specifically, in the range of 0.01 μm to 75 μm, 0.01 μm to 50 μm, 0.01 μm to 30 μm, 0.01 μm to 20 μm, 0.01 μm to 10 μm, 0.01 μm to 5 μm, 0.01 μm to 3 μm, 0.01 μm to 2 μm, 0.01 μm to 1 μm, 0.1 μm to 100 μm, 1 μm to 100 μm, 1 μm to 20 μm, 1 μm to 10 μm, 1 μm to 5 μm, 1 μm to 3 μm, 0.5 μm to 2 μm, 2 μm to 6 μm, 5 μm to 20 μm, 10 μm to 20 μm, 1 μm to 9 μm, or 1.5 μm to 6 μm.

[0058] By controlling the average particle diameter (D 50 ) of the inorganic compound in the above range, the present application can more effectively absorb the surrounding heat due to the large surface area when a thermal event occurs, thereby preventing or delaying the occurrence of a fire when the internal temperature of the battery pack rapidly increases. In addition, the present application can prevent accidents caused by dust generated during the manufacture of the fire extinguishing composition due to the average particle diameter being less than the lower limit of the range, and can increase the dispersibility of the manufactured fire extinguishing composition. In addition, the present application can prevent the endothermic performance of the inorganic compound from being reduced due to the average particle diameter being greater than the upper limit of the range, while preventing a decrease in the state stability during long-term storage.

[0059] The polycarboxylic acid compound is used as a chelating agent of the inorganic compound included in the fire extinguishing composition to facilitate the formation of a uniform fire extinguishing film on the surface of the spraying point after the fire extinguishing composition is sprayed without agglomeration of the inorganic compound.

[0060] To this end, the polycarboxylic acid compound can include a compound including two or more carboxyl groups (-COOH), and specifically can include one or more of malonic acid, citric acid, malic acid, oxalic acid, glutamic acid, aspartic acid, an amino acid, a fatty acid, methane tricarboxylic acid, ethane tricarboxylic acid, benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzene tricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid, benzene-1,2,3,4,5-pentacarboxylic acid, and benzene-1,2,3,4,5,6-hexacarboxylic acid (= benzenehexacarboxylic acid).

[0061] For example, the polycarboxylic acid compound can include citric acid, malic acid, and / or malonic acid.

[0062] Further, the inorganic compound and the polycarboxylic acid compound can be included in the fire extinguishing composition in a predetermined content ratio to enhance fire resistance. Specifically, when the fire extinguishing composition includes 100 parts by weight of the inorganic compound, it can include 0.01 to 5 parts by weight of the polycarboxylic acid compound, more specifically, the content of the polycarboxylic acid compound can be 0.01 to 4 parts by weight, 0.01 to 3 parts by weight, 0.01 to 2 parts by weight, 0.01 to 1 part by weight, 0.05 to 5 parts by weight, 0.1 to 5 parts by weight, 0.5 to 5 parts by weight, 1 to 5 parts by weight, 2 to 5 parts by weight, 3 to 5 parts by weight, 4 to 5 parts by weight, 1 to 4 parts by weight, 1 to 3 parts by weight, 2 to 4 parts by weight, or 1.5 to 3 parts by weight.

[0063] Further, the fire extinguishing composition can have a slurry form in which the inorganic compound and the polycarboxylic acid compound are mixed in a solvent, in which the solvent can be water (H2O). Water can not only be used as a solvent to be mixed with various fire retardants, but also can absorb a considerable amount of surrounding heat while evaporating into water vapor. Further, water increases in volume by about 1,600 times upon evaporation, and thus it can rapidly reduce the oxygen concentration at the fire occurrence point, which has an excellent smothering effect. Further, insulating oils such as silicone oil used as a solvent in conventional fire extinguishing compositions are generally flammable, and when they are not flammable, they are expensive, and thus there is a problem of low economic efficiency. In contrast, water has the advantage of not only being non-flammable but also excellent economic efficiency.

[0064] On the other hand, the time of spraying the fire extinguishing composition is immediately before or after the rapid temperature increase and the gas discharge of the battery cell, in which case the water included in the sprayed fire extinguishing composition can penetrate into the inside of the battery cell. The water that penetrates into the inside of the battery cell is easily reacted with the electrolyte again to accelerate the generation of a gas such as hydrogen fluoride (i.e., hydrofluoric acid) that is harmful to the human body, thus highly likely to cause a fire that generates more heat than a general fire, and there is a limitation in responding to the generated fire. Therefore, the fire extinguishing composition according to the present application can be adjusted so that the inorganic compound and the polycarboxylic acid compound are mixed with water, but the solid content satisfies a predetermined range. Specifically, the solid content of the fire extinguishing composition can be in the range of 10 wt% to 90 wt%, specifically, the solid content can be in the range of 10% to 90%, 15% to 90%, 20% to 90%, 25% to 90%, 30% to 90%, 35% to 90%, 40% to 90%, 45% to 90%, 50% to 90%, 55% to 90%, 60% to 90%, 65% to 90%, 70% to 90%, 75% to 90%, 10% to 50%, 10% to 40%, 25% to 50%, 30% to 80%, 40% to 70%, 51% to 90%, 51% to 80%, 51% to 70%, 55% to 75%, 45% to 60%, or 51% to 65% by weight.

[0065] The present application can easily mix the inorganic compound and the polycarboxylic acid compound while appropriately reducing the water content in the fire extinguishing composition by controlling the solid content of the fire extinguishing composition in the above range. In addition, when the mixture of the inorganic compound and the polycarboxylic acid compound in the form of a powder is sprayed, it is difficult to form a fire extinguishing film on the surface of the point where the fire extinguishing composition is dispersed. However, the fire extinguishing composition of the present application has a slurry form in which the inorganic compound and the polycarboxylic acid compound are mixed with water, thus after being coated on the surface of the point where the fire extinguishing composition is sprayed, the water evaporates to uniformly form a fire extinguishing film. The fire extinguishing film not only exhibits an effect of cooling the point where the fire extinguishing composition is sprayed and its surroundings without additional reaction with the battery cell because a small amount of water evaporates during the formation process, but also can effectively prevent oxygen in the inside air from being supplied to the point where the thermal event occurs after the film is formed.

[0066] In the case where the slurry has a high solid content, high viscosity is shown, in which case, not only is the fire extinguishing composition not easily sprayed, but the sprayed fire extinguishing composition is sprayed in a lump, unable to form a coating, and thus even if the water in the composition evaporates, it is difficult to form a fire extinguishing film. Therefore, the fire extinguishing composition according to the present application can satisfy a predetermined viscosity at room temperature to form a coating and transform into a fire extinguishing film after spraying. Specifically, the viscosity of the fire extinguishing composition at 25±3°C can be in the range of 2,000 mPa·s to 10,000 mPa·s. For example, the viscosity of the fire extinguishing composition at 25±3°C can be in the range of 2,000 mPa·s to 8,000 mPa·s; 2,000 mPa·s to 6,000 mPa·s; 2,000 mPa·s to 4,000 mPa·s; 2,000 mPa·s to 5,000 mPa·s; 2,500 mPa·s to 5,000 mPa·s; 3,000 mPa·s to 4,500 mPa·s; 4,000 mPa·s to 5,000 mPa·s; 4,000 mPa·s to 6,000 mPa·s; 4,000 mPa·s to 8,000 mPa·s; 5,000 mPa·s to 9,000 mPa·s; 5,100 mPa·s to 9,000 mPa·s; 6,000 mPa·s to 8,000 mPa·s; 7,000 mPa·s to 9,900 mPa·s; 2,500 mPa·s to 3,500 mPa·s; 2,000 mPa·s or more and less than 5,000 mPa·s; or 5,000 mPa·s or more and less than 9,000 mPa·s.

[0067] By satisfying the room temperature viscosity of the fire extinguishing composition in the above range, when a thermal event occurs inside the battery pack, the present application can spray the fire extinguishing composition in a slurry state having a high solid content without clogging the spraying device. In addition, the sprayed fire extinguishing composition can uniformly form a coating, and the time required for the water contained in the fire extinguishing composition to evaporate is short, and thus the fire extinguishing response time can be shortened.

[0068] The fire extinguishing composition can further include a separate viscosity modifier to control the viscosity at room temperature to be within the above range. The viscosity modifier can further include one or more viscosity modifiers among sodium alginate, pectin, gelatin, a high molecular polysaccharide, a cellulose compound, a nonionic surfactant, bentonite, and a borate.

[0069] The fire extinguishing composition can have a pH close to neutral by further including a pH control agent. The fire extinguishing composition includes a polycarboxylic acid compound and an inorganic compound, and exhibits a pH range of 3 to 4, which is weakly acidic in itself. However, when the fire extinguishing composition has a weakly acidic pH, not only does corrosion of facilities for storing and supplying the fire extinguishing composition occur when applied to a battery pack, but also the performance of the fire extinguishing composition has a problem of being reduced due to the corrosion. Therefore, the composition can further include a pH control agent to have a pH close to neutral, specifically a pH range of 5 to 7.5, pH 5 to 6.5, pH 5.5 to 7, pH 6 to 7.5, or pH 6.5 to 7.5.

[0070] The pH control agent can further include one or more pH control agents among sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium chloride, ammonium molybdate, ammonium bromate, ammonium acetate, ammonium nitrate, and ammonium sulfate.

[0071] For example, the pH control agent can include ammonium phosphate, and among them, ammonium dihydrogen phosphate (NH4H2PO4) can be included.

[0072] The pH control agent serves to neutralize the fire extinguishing composition while absorbing and cooling the surrounding heat generated during thermal decomposition, and to generate a non-flammable gas to achieve a smothering effect. In particular, ammonium dihydrogen phosphate is thermally unstable and starts thermal decomposition at about 150°C, and can undergo a stepwise endothermic process by thermal decomposition at about 190±10°C, about 215±10°C, about 300±10°C, and about 250±10°C by the following reactions: [Reaction Formula 1] NH4H2PO4→ H3PO4 + NH3 [Reaction Formula 2] 2H3PO4→ H4P2O7 + H2O [Reaction Formula 3] H4P2O7→ 2HPO3 + H2O [Reaction Formula 4] 2HPO3→ P2O5 + H2O.

[0073] The fire extinguishing composition according to the present application can achieve a cooling effect, a smothering effect, etc. by uniformly forming a fire extinguishing film in a short time at a point where a thermal event occurs inside the battery pack having the above-described configuration. Therefore, the fire extinguishing composition can prevent the spread of fire and has an excellent fire extinguishing effect. In addition, the fire extinguishing composition has the advantage of being not only environmentally friendly but also economical because it has a slurry form in which inorganic compounds and polycarboxylic acid compounds are dispersed in water.

[0074] Battery pack

[0075] In addition, the present application provides a battery pack including the above-described fire extinguishing composition.

[0076] Specifically, the battery pack includes a battery assembly including a plurality of battery cells arranged in a first direction; and a packaging case in which the battery assembly is accommodated, and the packaging case includes a fire extinguishing portion 20 provided on at least one inner surface of a top surface and a side surface to spray the above-described fire extinguishing composition of the present application when a thermal event occurs.

[0077] The battery pack includes a fire extinguishing portion 20 that sprays the above-described fire extinguishing composition on an inner surface of a packaging case in which a battery assembly is accommodated, and has an excellent fire extinguishing effect while preventing the spread when a thermal event such as flame spouting and fire occurrence occurs inside.

[0078] In addition, when a thermal event occurs, the battery pack does not spray the fire extinguishing composition to the entire inside, but the fire extinguishing portion 20 can be quickly moved to a point where a thermal event occurs and directly concentrate the fire extinguishing composition to the corresponding point. In this way, the battery pack can respond more quickly to a thermal event, so it has the advantage of excellent safety.

[0079] Here, the thermal event refers to a case where the internal temperature of the battery pack rapidly and abnormally rises to a range of 100°C or more, 150°C or more, 200°C or more, or 250°C or more, or gas discharge, flame spouting, fire occurrence, etc. occur inside the battery pack. Once a thermal event occurs, one or more of the above-described phenomena occur simultaneously or in a chain reaction.

[0080] Figure 1 is a structural view that schematically shows the structure of a battery pack and the working principle of a fire extinguishing portion according to the present application. Hereinafter, the battery pack 1 according to the present application will be described with reference to Figure 1 The battery pack 1 according to the present application will be described with reference to

[0081] The battery pack 1 includes a battery assembly 10 including a plurality of battery cells arranged in a first direction (a direction parallel to the X-axis), and a package case 50 in which the battery assembly is accommodated. At this time, the battery cells included in the battery assembly 10 can be pouch-type battery cells, prismatic battery cells, cylindrical battery cells, or the like, and preferably can be pouch-type battery cells. In this case, the battery assembly 10 can have a form in which a plurality of pouch-type battery cells are arranged in a thickness direction of the battery cells.

[0082] Further, the battery assembly 10 can refer to a battery stack in which a plurality of battery cells are fixed by a frame structure, and in some cases, can refer to a battery module including a plurality of battery cells.

[0083] Further, the battery pack can have a predetermined separation distance between the battery assembly 10 and the package case 50, so that when a thermal event occurs, the fire extinguishing portion can also move to a point where the thermal event occurs. For example, the battery assembly 10 and the package case 50 can have a separation distance of 5 cm to 20 cm, 5 cm to 15 cm, 5 cm to 10 cm, 10 cm to 20 cm, or 15 cm to 20 cm therebetween.

[0084] Further, the battery pack 1 can include a device for moving the fire extinguishing portion to a corresponding point when a thermal event occurs.

[0085] For example, in order to detect a point where a thermal event occurs, a sensing portion 30 that detects a change in temperature, a change in concentration of internal air components, whether a flame occurs, or the like when a thermal event occurs can be provided in the battery assembly 10.

[0086] Specifically, the battery assembly 10 can be equipped with one or more detection sensors 31 among a plurality of temperature detection sensors that detect a surface temperature of the battery assembly 10, a gas detection sensor that detects a concentration of an exhaust gas contained in internal air of the battery pack 1, and a flame detection sensor that detects whether a flame occurs and a position where the flame occurs.

[0087] The temperature detection sensor is mounted on a surface of the battery assembly and can measure a surface temperature of the battery assembly in real time. At this time, the temperature detection sensor can be mounted a plurality of times to have a predetermined separation distance on the surface of the battery assembly in the first direction, or can be independently mounted on each of a plurality of battery cells constituting the battery assembly.

[0088] Further, the gas detection sensor can measure the composition and concentration of the internal air changed due to the gas emission of the battery cell. The gas emission of the battery cell refers to that the internal temperature of the battery cell is increased due to the electricity, heat, and physical external stress of the battery cell, and thus, the gas generated from the evaporation or decomposition of the electrolyte is discharged to the outside of the battery cell. At this time, the discharged gas contains hydrocarbon gases such as methane and ethane, and carbon oxide gases such as carbon monoxide (CO) and carbon dioxide (CO2). Accordingly, the gas detection sensor can measure the concentration of the hydrocarbon gas and the carbon oxide gas as the emission gas in the air composition inside the battery pack.

[0089] Further, the flame detection sensor is equipped with an infrared LED and can detect whether the flame occurs by measuring the infrared wavelength (110 nm to 760 nm) originating from the flame when the flame is emitted and / or the fire occurs.

[0090] The plurality of gas detection sensors can be installed on the surface having the battery assembly or on the inner surface of the packaging case 50 adjacent to the battery assembly 10 at a predetermined separation distance along the first direction.

[0091] Further, the battery assembly 10 can include a control unit 40 electrically connected to the sensing part and receiving the results of the measurement or detection, and determining whether a thermal event has occurred from the received results.

[0092] For example, when the detection sensor 31 is a temperature detection sensor, the control unit 40 can obtain the surface temperature information of the battery assembly 10 measured by the plurality of temperature detection sensors. Thereafter, it calculates the temperature change per unit second based on the obtained temperature information, and if the calculated temperature change amount is +5℃ or more (i.e., a temperature rise of 5℃ or more), it can determine that a rapid temperature rise of 100℃ or more has occurred at the location of the temperature detection sensor that provides the corresponding temperature information.

[0093] When the detection sensor 31 is a gas detection sensor, the control unit 40 obtains information on the composition and concentration of the air inside the battery assembly 10 measured by the plurality of gas detection sensors, and based on the obtained information, when the concentration change of the hydrocarbon gas and the carbon oxide gas as the emission gas is 50 ppm to 1,000 ppm per unit second, it can determine that the gas emission has occurred.

[0094] When the detection sensor 31 is a flame detection sensor, the control unit 40 obtains infrared detection information measured by the plurality of flame detection sensors, confirms whether the infrared rays are detected based on the obtained infrared detection information, and when it is confirmed that the infrared rays are detected, it can determine that the flame emission and / or the fire has occurred.

[0095] When the control unit 40 determines that a thermal event has occurred from the information obtained from the sensing part 30, it can be determined that a thermal event has occurred at the position of the detection sensor 31 that transmitted the corresponding information among the plurality of detection sensors 31. When the occurrence position of the thermal event is determined, the control unit 40 can move the electrically connected fire extinguishing part 20 to the corresponding position to spray the fire extinguishing composition.

[0096] The control unit 40 can also function as a BMS (Battery Management System) that controls the charge and discharge of the battery pack 10. In addition, the control unit 40 can be provided on one side of the battery assembly 10, and in some cases, inside the package case 50.

[0097] Here, the fire extinguishing part 20 can include means for moving to a point where a thermal event has occurred and means for spraying a slurry-type fire extinguishing composition that satisfies a predetermined viscosity at room temperature.

[0098] Figures 2 to 4 is a view showing the structure of a fire extinguishing part and a spraying means and a rotating means included in the fire extinguishing part. Referring to Figures 2 to 4 , the fire extinguishing part 20 includes: a fire extinguishing agent storage part (not shown) located outside the package case 50 and storing a fire extinguishing composition; a gas storage part (not shown) located outside the package case 50 and storing an inert gas; a spraying means 21 that receives and sprays the fire extinguishing composition and the inert gas stored in the fire extinguishing agent storage part and the gas storage part, respectively, and is capable of rotating 180° along a direction perpendicular to the first direction; and a guide part 22 located on the inner surface of the package case 50 to move the spraying means 21 along the first direction of the battery assembly 10.

[0099] The fire extinguishing part 20 includes a spraying means 21 for spraying a slurry-type fire extinguishing composition, and the spraying means 21 can have a structure that sprays the fire extinguishing composition in a form mixed with an inert gas.

[0100] During normal operation of the battery pack 1, the fire extinguishing composition is maintained in a filled state in ① the fire extinguishing agent storage part that stores the fire extinguishing composition, ② the fire extinguishing part 20 installed inside the package case 50, and ③ the pipe part connecting the fire extinguishing agent storage part and the fire extinguishing part 20. However, when a thermal event occurs suddenly, the filled fire extinguishing composition is sprayed to the corresponding point where the thermal event occurs through the spraying means 21. At this time, since the dispersed fire extinguishing composition has been in a filled state for a long time in the fire extinguishing agent storage part and / or the pipe part, the dispersibility of each component can decrease and separation of solute and solvent can occur. In this case, the sprayed fire extinguishing composition cannot form a uniform fire extinguishing film, and thus the fire extinguishing performance is significantly reduced.

[0101] Accordingly, the fire extinguishing portion 20 according to the present application includes a fire extinguishing agent storage portion storing a fire extinguishing composition and a gas storage portion storing an inert gas outside the package case 50, respectively, and includes a spraying device 21 having a structure in which the fire extinguishing composition and the inert gas supplied from the respective storage portions are mixed, thereby preventing a decrease in dispersibility of the fire extinguishing composition.

[0102] Specifically, as shown in Figure 2 and Figure 3 the spraying device 21 includes: a slurry supply pipe 211 fluidly connected to the fire extinguishing agent storage portion to supply the fire extinguishing composition stored in the fire extinguishing agent storage portion; a gas supply pipe 212 fluidly connected to the gas storage portion to supply the inert gas stored in the gas storage portion; a spraying body 213 fluidly connected to the slurry supply pipe 211 and the gas supply pipe 212 to provide a space 213' in which the fire extinguishing composition and the inert gas supplied by them are mixed; and a nozzle 214 fastened to an end of the spraying body 213 to spray the mixture of the fire extinguishing composition and the inert gas.

[0103] The spraying device 21 has a structure that mixes the fire extinguishing composition and the inert gas supplied through the slurry supply pipe 211 and the gas supply pipe 212, respectively, in the spraying body immediately before spraying the fire extinguishing composition, and then sprays through the nozzle 214. In this way, the fire extinguishing composition mixed with the inert gas in the spraying body can have improved dispersibility of inorganic compounds and polycarboxylic acid compounds.

[0104] Further, the gas supply pipe 212 can further include a compression pump (not shown) that applies pressure to the inert gas to control the pressure (or flow rate) of the inert gas supplied to the spraying body 213. The pressure (or flow rate) of the inert gas supplied to the spraying body 213 can affect the spraying pressure (or flow rate) of the fire extinguishing composition sprayed from the nozzle 214. When the viscosity is higher than water, as in the fire extinguishing composition according to the present application, the spraying angle can become narrower and the spraying distance can become shorter during spraying, compared to the case of having low viscosity. When the spraying angle of the fire extinguishing composition becomes narrower and the spraying distance becomes shorter, the position control of dispersing the fire extinguishing composition can become more difficult, and a larger amount of the fire extinguishing composition is used to form a uniform fire extinguishing film at a point where a thermal event occurs. However, the present application separately includes a compression pump in the gas supply pipe 212 to control the flow rate of the fire extinguishing composition sprayed from the nozzle by pressure control of the inert gas mixed with the fire extinguishing composition, so the position control of spraying the fire extinguishing composition is easy. Therefore, even when a small amount of the slurry-type fire extinguishing composition is used, the present application can form a uniform coating at a point where a thermal event occurs.

[0105] Further, the spraying body 213 can include a rotating device 215 that rotates the spraying body 213, so that the fire extinguishing portion 20 can concentrate the fire extinguishing composition to be sprayed to the point where the thermal event occurs.

[0106] The fire extinguishing portion 20 includes a guide portion 22 located on the inner surface of the packaging case 50 to move the spraying device 21. However, since the guide portion 22 moves only in the first direction of the battery assembly 10 (a direction parallel to the X axis), it is difficult for the spraying device 21 to move in a direction perpendicular to the first direction, i.e., a direction parallel to the Y axis or the Z axis direction. Accordingly, the spraying body 213 of the spraying device 21 can include a rotating device 215 that rotates about a rotation axis substantially parallel to the first direction. Thus, the rotating device 215 can rotate in a direction perpendicular to the first direction of the battery assembly 10. Here, the direction perpendicular to the first direction of the battery assembly 10 can mean i) a second direction perpendicular to the first direction of the battery assembly 10 (i.e., a direction parallel to the Z axis direction) when the rotating device 215 is disposed on the inner surface of the packaging case 50, or ii) a third direction perpendicular to the first direction of the battery assembly 10 (i.e., a direction parallel to the Y axis direction) when the rotating device 215 is disposed on the inner top surface of the packaging case 50. The rotating device 215 can concentrate the fire extinguishing composition to be sprayed to the point where the thermal event occurs by directly rotating the spraying body 213 so that the nozzle 214 of the spraying device 21, which disperses the fire extinguishing composition, faces the point where the thermal event occurs.

[0107] At this time, the rotating device 215 is capable of rotating 180° in the direction perpendicular to the first direction. Accordingly, the rotating device 215 can easily spray the fire extinguishing composition by rotating the spraying device 21 from one end to the other end by 180° with respect to the battery assembly 10 in the direction perpendicular to the first direction.

[0108] The rotating device 215 can include a motor 215-1 that provides a rotating power to rotate the spraying device 21, and a gear 215-2 that causes rotation according to the rotating power of the motor. Specifically, as shown in FIG. 6, the spraying body 213 can be rotated by including the motor 215-1, a first gear 215-2a, a shaft 215-3, and a second gear 215-2b. The orientation of the spraying body 213 can be controlled by the motor 215-1, the first gear 215-2a, the shaft 215-3, and the second gear 215-2b. Further, the orientation of the spraying body 213 can be controlled by receiving position information determined according to the detection information measured by the sensing portion 30 from the control unit 40. Accordingly, the spraying device 21 can concentrate the fire extinguishing composition to be sprayed to the point (or the adjacent point) where the thermal event occurs, and in this way, it can quickly respond to the thermal event. Figure 4

[0109] ​The motor 215-1 can be configured to generate a driving force for rotating the nozzle 214. The motor 215-1 can be, for example, a precision control motor such as a servo motor and a stepping motor.

[0110] Further, a first gear 215-2a can be interposed between the motor 215-1 and the nozzle 214. A second gear 215-2b can be interposed between the first gear 215-2a and the nozzle 214. Each of the first gear 215-2a and the second gear 215-2b can be, for example, a helical gear or a spur gear. The first gear 215-2a and the second gear 215-2b can be connected by, for example, a shaft 215-3, but are not limited thereto. The shaft 215-3 can be omitted, and the first gear 215-2a and the second gear 215-2b can directly contact each other. The driving force generated by the motor 215-1 can be transmitted to the nozzle 214 via the first gear 215-2a, the shaft 215-3, and the second gear 215-2b, and the nozzle 214 can be rotated by the driving force.

[0111] Further, the fire extinguishing portion 20 includes a guide portion 22 to move along the extension direction (i.e., the first direction) of the space formed between the battery assembly 10 and the packaging case 50, thereby moving the spraying device 21 to the point (or adjacent point) where the thermal event occurs, within the space.

[0112] The guide portion 22 can be directly formed on at least one inner surface of the top surface and the side surface of the packaging case 50. When the guide portion 22 is directly formed on the inner surface of the packaging case 50, no additional space for forming the guide portion 22 is required, and the guide portion 22 can be formed when the packaging case 50 is manufactured, thus improving the energy density and manufacturing workability of the battery pack 1.

[0113] The guide portion 22 can be provided as a groove, a protrusion, or a slit formed on the inner surface of the packaging case 50. For example, the guide portion 22 can be a groove, a protrusion, or a slit having a form in which the length extends along the extension direction (a direction parallel to the X-axis) of the packaging case 50 on the inner surface of the packaging case 50.

[0114] On the other hand, the spraying body 213 of the spraying device 21 can be provided with a fixing device 216 for being fixed to the guide portion 22 by the rotating device 215. The fixing device 216 can be provided on the outside of the rotating device 215 included in the spraying body 213, and can have a complementary structure corresponding to the guide portion 22, thereby being fastened together with the guide portion 22 in the form of a groove, a protrusion, or a slit. The fixing device 216 can be configured such that the portion fastened together with the guide portion 22 moves along the extension direction without deviating from the guide portion 22.

[0115] Further, the fire extinguishing portion 20 can include a driving unit (not shown). The driving unit can be configured to provide power to the spraying device 21. The driving unit can be combined with the spraying device 21. The driving unit can include, for example, a motor and a roller driven by the motor. In this case, the roller can work according to the rotation of the motor while being in contact with the guide portion 22, thereby allowing the spraying device 21 to move along the extension direction of the guide portion 22.

[0116] Further, the fire extinguishing portion 20 can be configured to be driven by power supplied from the battery pack 1 itself. That is, the battery pack 1 of the present application can be configured to receive power required for the operation of the driving unit and / or the operation of the spraying device 21 (spraying operation of the fire extinguishing composition) from a part of the battery cells included in the battery assembly of the battery pack 1 itself, without receiving power supply through a separate power device. In this case, since a separate battery for driving the fire extinguishing portion 20 is not required, the structure of the battery pack 1 can be simplified.

[0117] Although not specifically shown in the drawings, the battery pack 1 of the present application can be configured such that the fire extinguishing portion 20 receives power required for the operation from the battery cells of the battery assembly 10 included in the battery pack 1, among the battery cells in which no thermal event has occurred. For example, the driving unit provided in the fire extinguishing portion 20 can be individually electrically connected to the plurality of battery cells included in the battery assembly 10. A switch can be individually provided on a power supply line connecting the driving unit and each battery cell. Each switch can be connected to the control unit 40 of the present application. The control unit 40 can be configured to control the switch installed on the power supply line connecting the battery cell located farthest from the battery cell in which a thermal event has occurred and the driving unit to be in an on state, and to control the switches connected to the other battery cells and the driving unit to be in an off state.

[0118] Further, the fire extinguishing portion 20 can include a pipe portion connected to the spraying device 21 and configured to supply the fire extinguishing composition and / or the non-active gas to the spraying device 21. The pipe portion can include a slurry supply pipe 211 supplying the fire extinguishing composition stored in the fire extinguishing agent storage portion to the spraying body 213 and a gas supply pipe 212 supplying the non-active gas stored in the gas storage portion to the spraying body 213. The pipe portion can extend along the first direction (a direction parallel to the X-axis) and be led out to the outside of the battery pack 1. When the extension direction of the pipe portion extends along the direction parallel to the extension direction of the guide portion 22 (the direction parallel to the X-axis) like this, it is possible to minimize the phenomenon of causing interference with other components inside the battery pack 1 according to the movement of the fire extinguishing portion 20.

[0119] Furthermore, the pipe portion can be composed of a material that can be deformed to minimize the constraint that occurs when the fire extinguishing portion 20 moves and can be wound on a reel so that the length can be adjusted during normal operation of the battery pack 1.

[0120] The battery pack according to the present application has the advantage that, by having the above configuration, it is possible to quickly detect the point at which a thermal event has occurred and directly concentrate the fire extinguishing composition to the corresponding point, so that it is easy to prevent the thermal event from spreading, and the time required to resolve the event can be shortened.

[0121] Hereinafter, the present application will be described in more detail through examples and experimental examples.

[0122] However, the following examples and experimental examples are merely illustrative of the present application, and the scope of the present application is not limited to the following examples and experimental examples.

[0123] Examples 1 to 7 and Comparative Examples 1 to 5. Preparation of fire extinguishing composition

[0124] Aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), and aluminum oxide (Al2O3) were prepared as inorganic compounds, respectively, and citric acid was prepared as a polycarboxylic acid compound. At this time, inorganic compounds having an average particle diameter (D 50 ) of about 1 to 5 μm were used. In addition, ammonium dihydrogen phosphate (NH4H2PO4) was prepared as a pH controller. Based on 100 parts by weight of the prepared inorganic compound, the polycarboxylic acid compound was weighed in the amounts shown in Table 1 below and mixed, and then water was added to the mixture. Then, while the mixture to which water was added was stirred at 500 ± 50 rpm for 10 minutes, the pH controller was added so that the pH of the mixture became 7.0 ± 0.3, and sodium alginate was used as a viscosity regulator, and the room temperature viscosity was controlled as shown in Table 1. Then, stirring was performed at the same stirring speed for 10 to 20 minutes to prepare a fire extinguishing composition for a battery pack. At this time, the solid content based on weight of each of the prepared fire extinguishing compositions was measured. The results are shown in Table 1.

[0125] [Table 1]

[0126] Experimental Example

[0127] In order to evaluate the fire extinguishing performance of the fire extinguishing compositions prepared in the examples and comparative examples, the following experiment was performed.

[0128] Specifically, in order to simulate a battery pack in which a thermal event has occurred, a chamber corresponding to the case of the battery pack was prepared. At this time, the chamber was installed on the inner top surface in a state in which a fire extinguishing agent tank storing the fire extinguishing composition and a nozzle spraying the fire extinguishing composition were connected by a pipe to spray the fire extinguishing composition.

[0129] In addition, 10 secondary battery cells of 1 Ah level were prepared, and each of the prepared secondary battery cells was charged so that the SOC became 100%. The 10 prepared secondary battery cells were assembled into a box-type battery assembly, and then installed in a chamber so that each secondary battery cell was stacked. At this time, the battery assembly was set so that an aluminum plate having a predetermined thickness was bolted to the upper and lower portions of each secondary battery cell, a pressurized structure of the secondary battery cells was exhibited within the assembly, and each secondary battery cell was pressurized by the bolted aluminum plate. In addition, an aluminum cooling plate was individually inserted between the upper and lower aluminum plates and the secondary battery cells; and between the stacked secondary battery cells. A heating pad (a silicone heater manufactured by Hotcow Co., Ltd., SBH2012) was installed between the lowermost secondary battery cell and the aluminum plate, and the heating pad was heated, thereby heating the secondary battery cells at a temperature increase rate of 7°C / minute to induce thermal runaway. When the secondary battery caught fire due to thermal runaway, the fire extinguishing composition (100 g to 150 g) was sprayed for 5 seconds through a nozzle provided on the inner top surface of the chamber.

[0130] ① The time taken for the secondary battery cell to be extinguished immediately after the fire extinguishing composition was sprayed was measured. In addition, ② when the temperature inside the chamber was cooled to room temperature, the installed battery assembly was taken out and the form of the fire extinguishing composition remaining in the region where the fire extinguishing composition was sprayed was visually evaluated.

[0131] At this time, the visual evaluation was rated as O, Δ, or X based on the criteria shown below: - O: The remaining fire extinguishing composition formed a uniform fire extinguishing film - Δ: The remaining fire extinguishing composition formed a fire extinguishing film, but the formed fire extinguishing film was not uniform, or there was a chunked fire extinguishing composition in addition to the fire extinguishing film - X: The remaining fire extinguishing composition did not form a fire extinguishing film and had a chunked form and / or a dot-dispersed form The results of the measurement and evaluation are shown in Table 2 below.

[0132] [Table 2]

[0133] As shown in Table 2 above, it can be seen that the fire extinguishing composition according to the present application has an excellent effect of extinguishing a fire occurring within a battery pack.

[0134] Specifically, it was confirmed that the fire extinguishing compositions of Examples 1 to 4 and Example 7 uniformly formed a fire extinguishing film on the surface of the point where the fire occurred after spraying, and thus, it was indicated that a significantly short fire extinguishing time of less than 210 seconds was required.

[0135] From these results, it can be seen that the fire extinguishing composition according to the present application, which contains an inorganic compound and a polycarboxylic compound in predetermined contents and has a viscosity at room temperature controlled in a predetermined range, is capable of uniformly forming a fire extinguishing film at a point where a thermal event occurs in a battery pack when the event occurs, so that a cooling effect and a smothering effect for fire extinguishing are high.

[0136] While the application has been described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes can be made therein without departing from the scope of the application as defined by the appended claims.

[0137] Accordingly, the scope of the present application should not be limited by the specific embodiments described in the specification, but should be defined by the appended claims.

[0138] [Legend of Reference Numerals]

[0139] 1: battery pack

[0140] 10: battery assembly

[0141] 20: fire extinguishing portion

[0142] 21: spraying device

[0143] 22: guide portion

[0144] 30: sensing portion

[0145] 31: detection sensor

[0146] 40: control unit

[0147] 50: package shell

[0148] 211: slurry supply pipe

[0149] 212: gas supply pipe

[0150] 213: spraying main body

[0151] 213': space in which the fire extinguishing composition and the non-reactive gas are mixed

[0152] 214: nozzle

[0153] 215: rotating device

[0154] 215-1: motor

[0155] 215-2: gear

[0156] 215-2a: first gear

[0157] 215-2b: second gear

[0158] 215-3: shaft

[0159] 216: fixing means

[0160] S: separation space between the battery assembly and the package case

[0161] M: inside of the battery pack

[0162] dx: X-axis direction

[0163] Rz: Z-axis rotation

Claims

1. A fire extinguishing composition comprising, wherein 100 parts by weight of an inorganic compound represented by chemical formula 1 and 0.01 to 5 parts by weight of a polycarboxylic acid compound are mixed in water, and Its features are, The viscosity of the fire extinguishing composition at 25±3°C is in the range of 2,000 mPa·s to 10,000 mPa·s. [Chemical Formula 1] M p O q (OH) r In chemical formula 1, Where M is magnesium or aluminum. Where p is an integer from 1 to 10, q is an integer from 0 to 20, and the condition is p ≤ q. Where r is an integer from 1 to 5.

2. The fire extinguishing composition according to claim 1, wherein the viscosity at 25±3°C is in the range of 2,000 mPa·s or more and less than 5,000 mPa·s.

3. The fire extinguishing composition according to claim 1, wherein the viscosity at 25±3°C is in the range of 5,000 mPa·s or more and less than 9,000 mPa·s.

4. The fire extinguishing composition according to claim 1, wherein the solid content of the fire extinguishing composition is in the range of 10% to 90%.

5. The fire extinguishing composition according to claim 1, wherein the inorganic compound represented by the chemical formula 1 comprises one or more of the following: boehmite, pseudoboehmite, diaspore, hexagonal alumina, aluminum hydroxide, and magnesium hydroxide.

6. The fire extinguishing composition according to claim 1, wherein the polycarboxylic acid compound comprises one or more of the following: malonic acid, citric acid, malic acid, oxalic acid, glutamic acid, aspartic acid, amino acids, fatty acids, methanetricarboxylic acid, ethanetricarboxylic acid, benzene-1,3,5-tricarboxylic acid, 5-sulfono-1,2,4-benzenetricarboxylic acid, ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid, benzene-1,2,3,4,5-pentacarboxylic acid, and benzene-1,2,3,4,5,6-hexacarboxylic acid.

7. The fire extinguishing composition according to claim 1, wherein the fire extinguishing composition further comprises one or more pH control agents selected from the following: sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, ammonium chloride, ammonium molybdate, ammonium bromate, ammonium acetate, ammonium nitrate, and ammonium sulfate.

8. The fire extinguishing composition according to claim 7, wherein the pH control agent is contained in an amount that causes the pH of the fire extinguishing composition to become 5 to 7.

5.

9. The fire extinguishing composition according to claim 1, wherein the fire extinguishing composition further comprises one or more viscosity modifiers selected from the following: sodium alginate, pectin, gelatin, high molecular weight polysaccharides, cellulose compounds, nonionic surfactants, bentonite, and borates.

10. A battery pack comprising a battery assembly, the battery assembly comprising: a plurality of battery cells arranged in a first direction; and a packaging shell therein housing the battery assembly. The packaging shell includes a fire extinguishing section disposed on at least one inner surface of the top surface and the side surface, thereby spraying the fire extinguishing composition of claim 1 in the event of a thermal event.

11. The battery pack of claim 10, wherein the thermal event includes any one or more of the following: a temperature rise of more than 100°C, gas discharge, flame ejection, and fire.

12. The battery pack of claim 10, wherein the battery assembly includes a sensing unit, the sensing unit comprising any one or more of the following detection sensors: Multiple temperature sensors are mounted on the battery assembly to detect the surface temperature of the battery assembly; A gas detection sensor for detecting the concentrations of carbon monoxide, carbon dioxide, and ethane in the internal air of the battery pack; and A flame detection sensor that detects whether a flame is present and the location of the flame.

13. The battery pack of claim 12, wherein the battery pack further comprises a control unit electrically connected to the sensing unit and the fire extinguishing unit, thereby obtaining information detected by the detection sensor of the sensing unit during a thermal event, determining from the obtained information whether a thermal event has occurred and its location, and moving the fire extinguishing unit to the corresponding location.

14. The battery pack of claim 10, wherein the fire extinguishing unit comprises: An extinguishing agent storage compartment located outside the packaging shell and storing the extinguishing composition; A gas storage section located outside the packaging shell and storing inactive gases; A spraying device that receives and sprays the extinguishing composition and inactive gas stored in the extinguishing agent storage section and the gas storage section respectively, and is capable of rotating 180° in a direction perpendicular to the first direction; and The guide portion of the spraying device is located on the inner surface of the packaging shell to move along the first direction of the battery assembly.

15. The battery pack of claim 14, wherein the spraying device comprises: A fluid supply pipe is connected to the extinguishing agent storage unit to supply the slurry of the extinguishing composition stored in the extinguishing agent storage unit; A gas supply pipe is fluidly connected to the gas storage unit to supply the inactive gas stored in the gas storage unit; A spray body is fluidly connected to the slurry supply pipe and the gas supply pipe to provide the space in which the extinguishing composition and inactive gas are mixed, supplied by them; and A nozzle that is fastened to the end of the spray body to spray the mixture of the extinguishing composition and the inactive gas.

16. The battery pack of claim 15, wherein the gas supply pipe further comprises a compression pump for applying pressure to the inactive gas, and The nozzle has a flow rate controlled by the pressure of the inactive gas supplied from the gas supply pipe.

17. The battery pack according to claim 15, wherein the spraying body is provided with: A rotating device comprising a motor configured to generate a driving force for rotation along a direction perpendicular to the first direction and a gear between the motor and the spraying body; and A fixing device is located between the rotating device and the guide portion to move the spraying body through the guide portion.

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