Secondary battery fire-retardant sheet, secondary battery comprising same, and pouch capable of accommodating same

Abstract

According to one embodiment of the present invention, a secondary battery fire-retardant sheet and a secondary battery comprising same may be provided, the secondary battery fire-retardant sheet comprising: a pair of protective sheets coated with a flame retardant material; and a fibrous member coated with or immersed in the flame retardant material, wherein the flame retardant material includes a fire extinguishing powder having at least one decomposition initiation temperature and an organic binder for dispersing and fixing the fire extinguishing powder. In addition, a pouch according to one embodiment of the present invention may include a fire extinguishing liquid or a fire extinguishing sheet immersed in the fire extinguishing liquid.

Description

A fire-retardant sheet for a secondary battery, a secondary battery including the same, and a pouch capable of accommodating the same

[0001] The present invention relates to a fire-retardant sheet for a secondary battery, a secondary battery including the same, and a pouch capable of containing the same.

[0002] Secondary batteries with a high concentration of electrical energy may be vulnerable to overcharging, physical shock, thermal shock, etc.

[0003] Rechargeable batteries create situations where responding to accidents is extremely difficult because they instantaneously release high energy accumulated due to internal defects or external impacts, inducing thermal runaway within a short period and accompanied by fire. In particular, dealing with thermal runaway and runaway flames resulting from fires that occur instantaneously during the manufacturing, storage, and transportation of semi-finished products, battery cells, finished battery modules, or battery packs is extremely challenging due to the speed at which the high-density energy of the rechargeable battery is converted into thermochemical combustion that causes the fire.

[0004] Conventional response methods for secondary battery fires focus on extinguishing the fire using traditional methods once it occurs.

[0005] In secondary batteries, many types of organic compounds are used as positive electrodes, negative electrodes, and electrolytes. Thermal runaway, a phenomenon associated with secondary battery fires, occurs when a high-temperature environment develops inside the battery due to physical or thermal shock or electrical short circuits. Consequently, high-temperature flammable gases are ejected from the internal cells, combining with oxygen inside and outside the pack to cause ignition due to electrical short circuits or high temperatures; this can be defined as thermal runaway and flame generation in the battery.

[0006] This phenomenon occurs when organic conductive contributing materials contained in the cathode and anode materials constituting the interior of the battery cell, as well as organic volatile compounds contained in large quantities in the electrolyte that contributes to the smooth movement of lithium ions between these materials, volatilize at high temperatures (above 150 degrees). Consequently, high-temperature volatile combustible gases accumulate within the sealed battery cell and battery pack until a certain pressure is maintained. These high-temperature combustible gases are then ejected into the battery pack at pressures exceeding a certain level, and the combustible gases ejected outside the battery pack combine with oxygen in the atmosphere and form a flame due to ignition sources inside or outside the battery pack.

[0007] There is a need for flame retardant technology that can prevent battery thermal runaway in advance or, even if thermal runaway occurs, rapidly suppress the generation of flames caused by flammable gases resulting from the runaway.

[0008]

[0009] In order to solve the technical problem to be achieved by the present invention, the purpose is to provide a secondary battery fire retardant sheet capable of effectively suppressing flames generated during a fire in a secondary battery.

[0010] The purpose is to provide a secondary battery capable of effectively suppressing flames generated during a fire.

[0011] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems can be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0012]

[0013] A secondary battery fire retardant sheet according to one embodiment of the present invention is,

[0014] A pair of protective sheets coated with a flame-retardant material; and

[0015] A fibrous member provided by coating or immersing the above flame-retardant material; comprising

[0016] The above flame retardant material is,

[0017] Digestible powder having at least one decomposition initiation temperature; and

[0018] It may include an organic binder that disperses and fixes the above-mentioned digestible powder.

[0019] According to one embodiment of the present invention,

[0020] The above protective sheet is,

[0021] It can be provided by being composed of at least one of glass fiber, carbon fiber, basalt fiber, rock wool, and aramid fiber and coated with graphene.

[0022] According to one embodiment of the present invention,

[0023] The above digestible powder is,

[0024] It may include at least one of alkali metals, alkaline earth metals, and ammonium-based materials.

[0025] According to one embodiment of the present invention,

[0026] The above digestible powder may be an inorganic carbonate powder.

[0027] According to one embodiment of the present invention,

[0028] The above alkali metal is,

[0029] It may include one or more of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), and potassium bicarbonate (KHCO3).

[0030] According to one embodiment of the present invention,

[0031] The above alkaline earth metals are,

[0032] It may include one or more of magnesium bicarbonate (Mg(HCO3)2), magnesium carbonate (MgCO3), calcium carbonate (CaCO3), and calcium bicarbonate (Ca(HCO3)2).

[0033] According to one embodiment of the present invention,

[0034] The above ammonium-based substance is,

[0035] It may include one or more of ammonium carbonate ((NH4)2CO3) and ammonium bicarbonate (NH4HCO3).

[0036] According to one embodiment of the present invention,

[0037] The above-mentioned digestive substance is,

[0038] The above flame retardant may be included in an amount of 60 to 95 weight percent relative to 1 weight part.

[0039] According to one embodiment of the present invention,

[0040] The above organic binder is

[0041] It may be included in an amount of 5 to 40 weight percent relative to 1 weight part of the flame retardant material.

[0042] A secondary battery according to one embodiment of the present invention is,

[0043] Battery pack;

[0044] A battery pack cover covering at least a portion of the battery pack; and

[0045] It includes a secondary battery fire retardant sheet provided on the inner side of the battery pack cover to cover the battery; and

[0046] The above secondary battery fire retardant sheet is,

[0047] A pair of flame-retardant protective sheets coated with a flame-retardant material; and

[0048] It may include a fibrous member provided by coating or immersing the above flame-retardant material.

[0049] In addition, a pouch according to another embodiment of the present invention is,

[0050] A main body that partitions storage space and includes an opening and closing part;

[0051] A cover capable of opening and closing the above-mentioned opening and closing part; and

[0052] It includes a extinguishing agent located within the above storage space, having one or more decomposition initiation temperatures, and comprising at least one of an alkali metal, an alkaline earth metal, and an ammonium-based substance.

[0053] Here, the opening and closing part and the cover may include a welding material so that the cover can be welded to the opening and closing part.

[0054] In addition, the above-mentioned main body is a pouch comprising a one-way valve through which internal gas can be discharged to the outside.

[0055]

[0056] According to one embodiment of the present invention, a secondary battery fire flame retardant sheet capable of effectively suppressing flames generated during a fire in a secondary battery can be provided.

[0057] According to one embodiment of the present invention, a secondary battery capable of effectively suppressing flames generated during a fire can be provided.

[0058]

[0059] FIG. 1 is a drawing showing a secondary battery fire retardant sheet according to one embodiment of the present invention, and

[0060] FIG. 2 is a photograph showing a flame-retardant material according to one embodiment of the present invention, and

[0061] FIG. 3 is a drawing of a secondary battery to which a secondary battery fire retardant sheet according to one embodiment of the present invention is applied.

[0062] FIGS. 4 and 5 are drawings illustrating a pouch according to an embodiment of the present invention.

[0063]

[0064] Hereinafter, an embodiment of a secondary battery fire retardant sheet according to the present invention and a secondary battery including the same will be described in detail with reference to the attached drawings.

[0065] It should be noted that when assigning reference numerals to the components of each drawing, the same components are assigned the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the embodiments of the present invention, if it is determined that a detailed description of related known components or functions would hinder understanding of the embodiments of the present invention, such detailed description is omitted.

[0066] In describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended merely to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by such terms. Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0067]

[0068] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0069]

[0070] FIG. 1 is a drawing showing a secondary battery fire retardant sheet (1000) according to one embodiment of the present invention.

[0071] As shown in FIG. 1, a secondary battery fire retardant sheet (1000) may include a pair of protective sheets (210, 220) coated with a liquid and paste-type flame retardant material (100) and a fibrous member (200) coated or immersed in the liquid and paste-type flame retardant material (100).

[0072] A pair of protective sheets (210, 220) are characterized by being coated with a liquid and paste-type flame retardant material (100) and having heat resistance and thermal conductivity characteristics, and being composed of a member coated with one of nano carbon and graphene, which exhibits non-combustibility and excellent thermal conductivity characteristics, such that it does not burn at high temperatures of 1200 degrees or higher even when in direct contact with a battery cell, module, or pack in the event of a secondary battery fire.

[0073] The fibrous member (200) is characterized by being coated or impregnated with a liquid and paste-type flame retardant material (100), and the fibrous member (200) may be composed of glass fiber, carbon fiber, basalt fiber, rock wool, aramid fiber, etc.

[0074] The above fibrous member is characterized by having a pore volume fraction of 10 to 99%, and a flame retardant material (100) is coated or impregnated on the three-dimensional fiber surface existing between the pores of the fiber, and the flame retardant material (100) coated or impregnated on the fiber can be attached in the form of a dry powder, liquid, or paste.

[0075]

[0076] In this embodiment, a secondary battery fire retardant sheet (1000) can be formed by first applying a liquid and paste-type flame retardant material (100) to one of the protective sheets (220), and then covering the top with another fiber sheet (210).

[0077] Alternatively, a secondary battery fire retardant sheet (1000) may be formed by first forming a pad shape by coating or immersing a fibrous member (200) with a flame retardant material (100) in a liquid or paste state, and then attaching a pair of fibrous sheets (210, 220) to both sides of the pad of the fibrous member (110) formed into a pad shape.

[0078] A fire-retardant sheet (1000) for secondary batteries may be provided to cover at least a portion of a secondary battery. Referring to FIG. 4, the fire-retardant sheet (1000) for secondary batteries may be provided to cover a battery pack (10) on the inside of a battery pack cover (20).

[0079] Since the secondary battery fire retardant sheet (1000) can be formed to correspond to the shape of the battery pack (10), it can stably cover the entire battery pack (10).

[0080]

[0081] The flame retardant material (100) is intended to suppress fire in a secondary battery and may include a fire-extinguishing powder (110) and an organic binder (120) that disperses and fixes the fire-extinguishing powder.

[0082] The extinguishing powder (110) may be a combination of carbonate ions, which have suffocation properties against fire and reactivity with lithium, and monovalent or divalent cations.

[0083] The extinguishing powder (110) may be an inorganic salt powder. The inorganic salt powder may include alkali metals, alkaline earth metals, and ammonium-based materials on the periodic table that have a strong oxygen radical absorption capacity.

[0084] One or more of the alkali metal series may be included among sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), and potassium bicarbonate (KHCO3).

[0085] In addition, alkaline earth metals may include one or more of magnesium bicarbonate (Mg(HCO3)2), magnesium carbonate (MgCO3), calcium carbonate (CaCO3), and calcium bicarbonate (Ca(HCO3)2).

[0086] In addition, ammonium-based substances may include one or more of ammonium carbonate ((NH4)2CO3) and ammonium bicarbonate (NH4HCO3).

[0087]

[0088] The extinguishing powder (110) may specifically be an inorganic carbonate powder. When the carbonate powder is decomposed by heat, reactive decomposition gas and cationic metal ions may be automatically ejected. The ejected reactive decomposition gas can decompose the combustible gas (lithium gas) ejected from the lithium-ion battery. The reactive decomposition gas ejected when the carbonate powder is decomposed by heat may be carbon dioxide (CO2). Additionally, the cationic metal ions can absorb radicals generated from electric sparks or flames, thereby blocking the chain reaction of combustion.

[0089]

[0090] [Chemical Formula 6]

[0091] 4Li + 2CO2 + O2 → 2Li2CO3

[0092]

[0093] [Chemical Formula 7]

[0094] 2Li + 2CO2 + H2O → 2LiHCO3

[0095]

[0096] Chemical formulas 6 and 7 above represent chemical formulas in which carbonate powder is decomposed by heat and carbon dioxide is released when a fire occurs in a lithium-ion battery.

[0097] As seen in Chemical Formulas 6 and 7 above, when a fire occurs in a lithium-ion battery, the carbonate powder may decompose due to the heat generated, releasing carbon dioxide. Then, the vaporizing lithium can be converted into carbonate and become non-combustible.

[0098] In this way, as the carbonate powder decomposes and releases carbon dioxide, and the access of oxygen is blocked due to the suffocating effect of the carbon dioxide, combustion caused by a lithium-ion battery fire can be effectively mitigated or effectively extinguished.

[0099]

[0100] Meanwhile, radical ions are generated by sparks occurring inside the lithium-ion battery. Additionally, when carbonate powder decomposes due to heat, cationic metal ions (e.g., alkali metals or alkaline earth metals) may be ejected.

[0101] Radical ions can be absorbed by cationic metal ions. Through this, spark generation can be suppressed, and the ignition of the lithium-ion battery can be blocked. In other words, due to this negative catalytic effect, the chain reaction of combustion in the lithium-ion battery can be suppressed. Therefore, it is possible to suppress the initial fire of the lithium-ion battery and prevent the spread of fire.

[0102] Carbonate powder according to the decomposition onset temperature as shown in Table 2 below

[0103] It can be formed by combining one or more of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), potassium bicarbonate (KHCO3), magnesium bicarbonate (Mg(HCO3)2), magnesium carbonate (MgCO3), calcium carbonate (CaCO3), calcium bicarbonate (Ca(HCO3)2), ammonium carbonate ((NH4)2CO3), and ammonium bicarbonate (NH4HCO3).

[0104]

[0105] Classification Chemical Formula Molecular Weight Decomposition Initiation Temperature (°C) Ammonium Bicarbonate NH4HCO3 79.0641~45 Ammonium Carbonate (NH4)2CO3 96.0960 Sodium Bicarbonate NaHCO3 8480 Sodium Carbonate Na2CO3 105.99100 Potassium Bicarbonate KHCO3 100.1100~120 Potassium Carbonate K2CO3 138.2850 Magnesium Carbonate MgCO3 84.3350 (Anhydrous) 165 (Trihydrate)

[0106] Here, the decomposition initiation temperature may be the temperature at which the decomposition of the carbonate powder begins. As shown in Figure 2, each carbonate powder may have a unique decomposition initiation temperature. Depending on the user's requirements, a carbonate powder with a suitable decomposition initiation temperature may be selected and blended.

[0107] Examples of carbonate powder formulations according to temperature can be carried out as shown in Table 3 below.

[0108]

[0109] Decomposition initiation temperature 60℃ 100℃ 150℃ Ammonium carbonate 55 wt% 10 wt% Potassium bicarbonate 20 wt% 60 wt% 10 wt% Magnesium carbonate 5 wt% 10 wt% 70 wt%

[0110] The disassembly initiation temperature can be selected by the user. The user may be a manufacturer of the lithium-ion battery or a manufacturer of a product equipped with the lithium-ion battery. The temperature range considered dangerous for the use of a lithium-ion battery may vary from user to user. For example, some users may determine that there is a fire risk or that a fire has occurred at temperatures above 60°C. Other users may determine that there is a fire risk or that a fire has occurred at temperatures above 100°C.

[0111] As such, the temperature range considered dangerous for the use of lithium-ion batteries may vary from user to user. Therefore, if a user determines a specific temperature range to be dangerous, some carbonate powders having a decomposition initiation temperature that falls within that dangerous temperature range, or having a decomposition initiation temperature lower or higher than that dangerous temperature even if it does not fall within that dangerous temperature range, may be appropriately selected and blended.

[0112] For example, if the danger temperature determined by the user is 60°C, the carbonate powder may contain 55% by weight of ammonium carbonate, 20% by weight of potassium bicarbonate, and 5% by weight of magnesium carbonate. The carbonate powder may be formed by a mixture of these. In this way, the ammonium carbonate, which accounts for the largest weight percentage, decomposes first at the danger temperature of 60°C, allowing the first extinguishing process to proceed. However, if the fire is not extinguished even by the first extinguishing action and the temperature increases further to 100–120°C, the potassium bicarbonate, which accounts for the next largest weight percentage, decomposes, allowing the second extinguishing process to proceed. Nevertheless, if the temperature continues to increase to the decomposition initiation temperature of magnesium carbonate, a third extinguishing process by magnesium carbonate may proceed. In other words, as the temperature increases, the extinguishing process can proceed in stages.

[0113] If the carbonate powder consists solely of materials having a decomposition initiation temperature within a single danger temperature range, the entire material will decompose at that temperature, triggering a fire suppression process. However, if complete extinguishment is not achieved despite this process, a rapid subsequent rise in fire temperature cannot be prevented, making it impossible to delay the onset of thermal runaway. This could result in a failure to provide the vehicle's driver with sufficient time to evacuate.

[0114] However, as in the present invention, if the fire extinguishing process proceeds in stages, a rapid rise in fire temperature can be prevented and the occurrence of thermal runaway can be delayed. Furthermore, this may bring about positive effects, such as providing time for the vehicle driver to evacuate.

[0115] In the lithium-ion battery fire suppressor (100), the carbonate powder may be included in an amount of 60 to 95 weight%, and the organic binder (120) may be included in an amount of 5 to 40 weight%. Preferably, the carbonate powder may be included in an amount of 80 weight%, and the organic binder (120) may be included in an amount of 20 weight%.

[0116] Additionally, the flame retardant material (100) can be mixed with an organic binder (120) containing one or more of an organic adhesive and rubbers to form a dispersed paste.

[0117] As a specific example, the flame retardant material (100) of FIG. 2 is a mixture of 80 weight% carbonate powder and 20 weight% soft polyurethane as an organic binder (120).

[0118]

[0119] The protective sheet manufacturing step may consist of a step in which a pre-manufactured flame retardant material (100) is coated onto the surface of the protective sheet (210, 220) by one or more methods of application, spraying, and immersion, and a step of heat-drying the flame retardant material (100) coated on the surface of the protective sheet at a temperature between 60 and 120 degrees.

[0120] Additionally, the fibrous member (200) comprises the steps of coating or impregnating a pre-manufactured flame-retardant material (100) onto the surface of the fibrous member in the form of application, spraying, and immersion, and heat-drying the flame-retardant material (100) coated or impregnated onto the surface of the fibrous member at a temperature between 60 and 120 degrees.

[0121] The secondary battery fire retardant sheet (1000) can be configured in a combined form of a pair of protective sheets (210, 220) coated with a flame retardant material (100).

[0122] Additionally, the secondary battery fire retardant sheet (1000) may be configured such that a fibrous member (200) coated or impregnated with a flame retardant material (100) is inserted between a pair of protective sheets (210, 220) coated with a flame retardant material (100).

[0123]

[0124] The secondary battery fire extinguishing device (1000) according to an embodiment of the present invention may be applied to the secondary battery itself as described above, but is not limited thereto and may also be applied to a case or pouch capable of housing or containing various electronic devices or small items that pose a fire risk.

[0125] For example, in a situation where a fire may occur in an auxiliary battery, mobile phone, charger, electric device battery pack, etc., the fire extinguishing sheet (200) of the present invention may be included inside a storage pouch (2000) capable of storing or accommodating such electronic devices or items, so that the fire extinguishing function is activated when a fire occurs.

[0126] Furthermore, it may be provided in the form of a fire extinguishing box having a predetermined shape, rather than in the form of a case or pouch. A fire extinguishing box refers to a box installed in airports, subway stations, or inside airplanes and subways to house objects that may cause fire, such as auxiliary batteries or secondary batteries, when a fire is anticipated. It goes without saying that such cases, pouches, and fire extinguishing boxes (hereinafter referred to as "pouches") are not limited to being placed in airplanes or subways to house secondary batteries as described above, but may also be provided as personalized storage containers for individual storage.

[0127] Such a pouch (2000) may include a fire extinguishing sheet (200) in which a fire extinguishing liquid (100) is laminated between non-combustible fiber members, or may include a fire extinguishing liquid (100) in a form in which the fire extinguishing liquid (100) is sprayed or impregnated inside the pouch (200), and when a high temperature or ignition condition occurring in an article is detected, the fire extinguishing liquid can react to suppress or extinguish a fire. For example, the outside of the fire extinguishing sheet (200) may be surrounded by a film, and the film may be arranged so that it melts at a temperature where a fire may occur, for example, 100 degrees Celsius or higher, thereby exposing the fire extinguishing sheet (200) or the fire extinguishing liquid (100) into the inside of the pouch (200). Accordingly, when an ignition condition is detected in an article contained inside, for example, an auxiliary battery, the fire extinguishing liquid (100) may be sprayed onto the article.

[0128] Furthermore, a fusion material may be applied to the opening and closing portion of the pouch (2000), that is, the opening and closing portion through which an item such as a secondary battery can enter or exit. The fusion material is provided as a thermosetting resin material in the part that comes into contact with each other when the opening and closing portion is opened and closed, and when placed in a high-temperature state, it sticks together and can seal the opening and closing portion. If a fire occurs in an item such as a secondary battery contained inside the pouch (2000) and the temperature rises, this fusion material can close the opening and closing portion to prevent the high-temperature item from being exposed to the outside. In addition, it can cut off the supply of oxygen in the event of ignition of the item.

[0129] In addition to this, the pouch (2000) can be molded into a certain shape and implemented as a portable small personal pouch (2000).

[0130]

[0131] A storage pouch (2000) equipped with a fire extinguishing sheet (200) according to the present invention can be configured to safely store and store flammable items such as various small electronic devices, auxiliary batteries, or secondary batteries that may cause fire, and to effectively suppress or extinguish a fire when it occurs in the stored items.

[0132]

[0133] The pouch (2000) may be formed with a flexible outer shell that is heat-resistant or flame-retardant, but is not limited thereto, and may, of course, be provided in the form of a rigid case. A storage space for accommodating the user's items may be provided inside the outer shell of the pouch (2000). The outer shell may include flame-retardant synthetic fibers, silicone-coated fabrics, aramid fibers, glass fibers, etc., and various opening and closing means such as zippers, Velcro, buttons, magnets, and roll-up structures may be used to open and close the storage space.

[0134]

[0135] The storage space of the pouch (2000) may be in the form of a single chamber or may have a structure separated into multiple compartments, and may be equipped with a rubber band or Velcro holder so that various electronic devices or parts such as auxiliary batteries, chargers, smartphones, earphone cases, and battery packs for power tools can be stored stably.

[0136] The storage space of the pouch (2000) may be formed with a structure in which a fire extinguishing sheet (200) having a fire extinguishing function is placed inside. The fire extinguishing sheet (200) may be arranged to be placed on the inner front surface of the pouch (2000), or it may be used as a structure itself that partitions the inner space. For example, the fire extinguishing sheet (200) may be placed on the bottom surface, side, or inside the top cover of the pouch (2000), or it may be placed on the inner front surface of the pouch (2000). Additionally, in some cases, it may be arranged to be placed in a partition or pocket structure that partitions the storage space of the pouch (2000), so as to be positioned to react immediately when an item stored inside the pouch (2000) catches fire and exceeds the fire extinguishing initiation temperature.

[0137]

[0138] A fire extinguishing sheet (200) may be formed in a laminated form with one or more fire extinguishing liquids (100) having a decomposition initiation temperature between a pair of fiber members (210, 220), and such a fire extinguishing sheet (200) may be placed in various ways inside a pouch (2000). For example, the fire extinguishing sheet (200) may be attached to the entire or partial surface of the inner lining of the pouch (2000), or may be received in an insertable manner through a separate pocket structure. In some embodiments, the fire extinguishing sheet (200) may be fixed to the wall or bottom surface of the storage space, or the fire extinguishing sheet (200) may be placed in a position that comes into direct contact with the stored item to be configured to react quickly upon ignition.

[0139]

[0140] The fire extinguishing sheet (200) contains a fire extinguishing liquid (100) having one or more decomposition initiation temperatures, and when the fire extinguishing initiation temperature is reached, the fire extinguishing liquid (100) initiates a reaction to suppress or extinguish a fire. Since the fire extinguishing liquid (100) used in this embodiment is the same as the secondary battery fire retardant catalyst fire extinguishing liquid (100) described above, a redundant description is omitted.

[0141]

[0142] The pouch (2000) of the present invention can be modified into various forms and, in addition to the general pouch (2000) structure, can be implemented in various forms such as a form attached inside a bag, a portable case type, or a module insertion type. Furthermore, the extinguishing sheet (200) may be designed to include a temperature sensor or a pressure sensor if necessary, so that a extinguishing reaction is automatically initiated when certain conditions are satisfied.

[0143]

[0144] Through such a structure, the pouch (2000) according to the embodiment of the present invention goes beyond a simple storage function and can effectively suppress or extinguish the spread of fire even if a fire occurs in an electronic device or other item stored inside the pouch (2000).

[0145]

[0146] Meanwhile, such a pouch (2000) may be configured to be movable when positioned in the form of a fire extinguisher box at an airport, subway station, inside an airplane, and inside a subway. To this end, the pouch (2000) may be equipped with roller-shaped wheels.

[0147]

[0148] Another embodiment of the present invention is described with reference to FIGS. 4 and 5. The secondary battery fire suppression case (4000) according to this embodiment is manufactured in the form of a case for the purpose of suppressing a fire. It may be manufactured in the same form as the pouch (2000) described above and may be referred to as the pouch (2000) in this specification, but it is described as a different embodiment with a focus on fire suppression. The secondary battery fire suppression case (4000) according to this embodiment mainly comprises a main body (4110), a fire extinguishing liquid (4120), and a cover (4130).

[0149]

[0150] The main body (4110) is made of a material capable of accommodating a portable secondary battery that is in a situation where a fire occurs or is likely to occur, and withstands flames and high temperatures. The main body (4110) may have a cylindrical or rectangular prism shape with an open top, and partitions a accommodating space (4112) inside. The main body (4110) is made of a material having high fire resistance and thermal insulation. For example, it may be made of a metal material such as stainless steel or aluminum alloy with a fire-resistant coating on its surface, or high-performance engineering plastic such as PEEK (polyetheretherketone) or high-temperature silicone.

[0151]

[0152] Alternatively, the main body (4110) may have a double-wall structure consisting of an inner wall and an outer wall. The space between the inner wall and the outer wall can be made into a vacuum or filled with high-efficiency insulating material such as aerogel or ceramic wool to minimize heat transfer to the outside and maximize safety so that the user does not get burned even if they touch the outer surface of the case. The edge of the upper opening of the main body (4110) may be formed in a funnel shape inclined inward, so that the user can easily insert the battery that has caught fire even in a panicked state.

[0153]

[0154] The fire extinguishing liquid (4120) may be pre-filled within the receiving space (112) of the main body (4110). The fire extinguishing liquid (4120) may be composed of a component capable of suppressing a lithium-ion battery fire and may be the fire extinguishing liquid (100) described above.

[0155]

[0156] The cover (4130) serves to selectively close the open top of the main body (4110). The cover (4130) may be screw-coupled to the main body (4110) or simply friction-coupled to cover it. The cover (4130) is also made of a fire-resistant material similar to that of the main body (4110), and a gasket (132) made of a heat-resistant material such as silicone is provided on the edge, thereby hermetically sealing the gap between the cover (4130) and the main body (4110) when the cover (4130) is closed. This effectively prevents toxic gases or smoke generated during the fire suppression process from leaking out.

[0157]

[0158] Alternatively, the cover (4130) may be equipped with a pressure relief valve (4134) that safely discharges internal gas to the outside when the pressure inside the case rises above a certain level. This valve has a one-way valve structure in which only internal gas is discharged without allowing external air to enter, and can serve as an important safety device to prevent the case from being damaged or exploding due to gas generated during the fire suppression process.

[0159]

[0160] Meanwhile, the cover (4130) may be an automatic closing cover. A structure capable of automatic closing may be applied to eliminate the need for the user to separately close the lid after inserting the fire battery. For example, the cover (4130) is hinge-connected to one side of the main body (4110) and configured to receive elastic force in a direction that always closes by means of a torsion spring or the like. When the user opens the lid (140), inserts the battery (B), and then lets go of the hand, the lid (140) automatically closes by the restoring force of the spring, immediately forming a sealed state. Alternatively, a swing door type lid may be applied in which a pair of semicircular covers are closed by a spring relative to the center, open by the weight when the battery (B) is inserted, and close immediately after the battery passes through.

[0161]

[0162] Meanwhile, the case according to an embodiment of the present invention may include a fire extinguishing liquid storage structure using a crushing container. That is, to prevent the fire extinguishing liquid (4120) from leaking out or evaporating during normal operation, instead of storing the fire extinguishing liquid (4120) directly inside the main body (4110), it may be stored in a sealed crushing container made of thin glass or brittle plastic. In this case, the bottom surface of the main body (4110) may not be flat and may be formed with an uneven structure to stably support the crushing container while allowing it to easily break upon impact. When a user throws a battery (B) that has caught fire into the case, the crushing container (150) breaks due to the impact, and the fire extinguishing liquid (4120) inside is instantaneously released, allowing the battery to be submerged. This method has the advantage of maintaining performance without deterioration of the fire extinguishing liquid even during long-term storage.

[0163]

[0164] Furthermore, the case according to an embodiment of the present invention may include a secondary battery crushing structure. That is, since a lithium-ion battery fire occurs in a cell inside the battery, the suppression effect can be maximized if the extinguishing liquid penetrates directly into the battery. To this end, a plurality of crushing protrusions protruding upward may be integrally formed on the bottom surface of the main body (4110). These protrusions are made of a very hard material such as metal or ceramic, and their ends may be processed to be sharp. When a battery that has caught fire is placed into the case, the outer casing of the battery may be torn or punctured by these crushing protrusions due to the impact of the fall. Through the hole thus created, the extinguishing liquid (4120) can come into direct contact with the cell inside the battery, thereby stopping the thermal runaway reaction more quickly and effectively.

[0165]

[0166] Meanwhile, glow-in-the-dark tape or paint may be applied to the exterior surface of the case to allow for easy identification of its location even in dark or smoky environments. Additionally, an insulated handle may be provided to enable the user to safely transport the high-temperature case, or a wall-mounting bracket may be provided for storage in a visible location. A temperature-sensing sticker that indirectly indicates the internal temperature may be attached to the side of the case, allowing the user to visually determine whether the case remains at a high temperature or has cooled to a safe temperature through changes in the sticker's color.

[0167]

[0168] Furthermore, the fire retardant sheet according to the embodiment of the present invention may be a sheet comprising various layers in addition to the form of the sheet described above, and an embodiment of the fire retardant sheet (5000) according to the embodiment of the present invention will be described.

[0169]

[0170] The fire retardant sheet (5000) according to an embodiment of the present invention relates to a fire retardant sheet (5000) having a multilayer structure with an integrated active fire extinguishing function, and includes a functional layer, and typically includes a symmetrical laminated configuration such as L3-L2-L1-L2-L3. However, it is not limited thereto, and it is understood that the layer may be provided only in the direction in which a fire may occur as described below, thereby having an L3-L2-L1 structure.

[0171] As shown in FIG. 6, a high-efficiency insulation layer (L2) and a high-speed heat discharge layer (L3) can be symmetrically arranged around a fire extinguishing core layer (L1). L1 (the first functional layer) may be a core sheet or a gel sheet capable of performing active fire extinguishing and heat endothermic functions. L1 is a layer that performs an active safety function by causing an endothermic reaction through thermal activation to absorb ambient heat and release fire extinguishing components to suppress flames.

[0172] In addition, the L2 (second functional layer) layer functions as an insulating layer and is placed on both sides of L1 to delay thermal runaway propagation, prevent premature activation of L1, and assist in the thermal diffusion efficiency of L3.

[0173] Next, L3 (the third functional layer) functions as a heat discharge or diffusion layer, rapidly dispersing heat generated externally or internally over a wide area and releasing it to the outside, thereby preventing localized accumulation of the heat source.

[0174] This symmetrical structure, such as L3-L2-L1-L2-L3, provides structural stability and enables efficient bidirectional thermal management and protection regardless of the direction from which thermal events occur within the sheet (from the inner cells outward, or from external impact / fire inward). L2 and L3 serve to mechanically and thermally protect L1's fire extinguishing function from being exposed to the external environment.

[0175]

[0176] Below, each functional layer is described in more detail as follows. The first functional layer (L1) is provided as an active extinguishing and endothermic core sheet or gel sheet. L1 is an active element for responding to thermal runaway and is activated when the temperature of the battery reaches a specific critical operating temperature. The activation of L1 suppresses thermal runaway through two main mechanisms. First, it can provide a cooling effect by rapidly lowering the ambient temperature through a large-scale endothermic reaction via phase change or decomposition of the material. Second, it can fundamentally suppress the generation of flames by releasing chemical extinguishing components. The aforementioned specific critical operating temperature may be a value between the separator damage temperature of the lithium-ion battery and the thermal runaway initiation temperature, for example, 140 degrees Celsius. L1 may be provided in the form of a gel or sheet in which the aforementioned fire retardant material is dispersed or impregnated at a high concentration in a polymer matrix. The fire retardant material can elevate the role of L1 to an 'active blocking' function beyond simple endothermic action.

[0177] The second functional layer (L2) may be a high-efficiency insulation layer. L2 serves to maximize the time-to-time delay of thermal runaway propagation (TTRP) and is positioned on both sides of L1 to physically block heat transfer from adjacent cells. L2 may have low thermal conductivity. L2 may be manufactured using ultra-insulating materials to simultaneously ensure high-efficiency insulation performance and flexibility. For example, aerogel-based composites may be used, specifically composites in which aerogel particles are combined with a polytetrafluoroethylene (PTFE) binder. These materials have very low thermal conductivity of 25 mW / (mK) or less, and in the form of composites, they do not significantly lose insulation properties even under bending, stretching, or flexing, making them highly advantageous for applications in flexible sheet forms. Alternatively, high-temperature resistant composites may be used; composites reinforced with aerogel within alumina paper or zirconia felt maintain a low thermal conductivity of 60 mW / (mK) even at 900 degrees Celsius and provide mechanical resilience and rigidity at high temperatures. Furthermore, materials containing a micro-insulating structure may be used, which can extend solid heat conduction paths and effectively block radiant heat transfer by dispersing hollow microspheres in a silicon elastomer substrate or partially incorporating a metal film (e.g., aluminum foil) for radiant heat reflection.

[0178] The third functional layer (L3) functions as a high-speed thermal discharge and diffusion layer. L3 can be located on the outer layer of L1 and L2 and rapidly transfers heat generated internally across the entire sheet surface (plane direction) or in the sheet thickness direction (vertical direction) to release heat to the outside, thereby preventing localized accumulation of thermal runaway and enhancing the operating effect of L1. The thermal conductivity in the plane direction can be 100 W / (mK) or higher, preferably 200 W / (mK) or higher. L3 can be provided with a high thermal conductivity material capable of efficiently conducting heat; to increase the plane conductivity, a structure in which an ultra-high thermal conductivity graphite sheet (graphite film) or a metal thin film such as copper / aluminum is laminated with a polymer substrate may be used. Additionally, to enhance vertical conduction, it can be provided as a functional layer that rapidly promotes heat conduction by being laminated parallel to the L1 sheet or introduced vertically. To increase the conductivity in the thickness direction, thermally conductive particles (e.g., aluminum nitride (AlN), silicon carbide (SiC)) may be oriented within the polymer substrate, or a mesogen skeleton material that forms an aligned structure for heat transfer may be used. For example, a composite sheet containing a mesogen skeleton can increase the thermal conductivity in the thickness direction to 9.8 W / mK or higher, which means more than double the efficiency compared to an unaligned structure.

[0179] Meanwhile, L3 can perform roles other than simply diffusing heat. Specifically, L3 acts as a mechanical support layer protecting L2 and L1 from external shocks. Furthermore, particularly after L1 is activated, it functions as a final heat sink that rapidly dissipates the heat passed through L2—which has been cooled via an endothermic reaction in L1—to the outside, thereby improving the cooling efficiency of the entire system.

[0180]

[0181] These fire-retardant sheets may have a symmetrical structure (L3-L2-L1-L2-L3). With L1 as the core layer, the L2 insulation layer and the L3 diffusion layer are symmetrically arranged to provide the most balanced bidirectional protection and heat dissipation against thermal events between internal cells or from the external environment. This can be inserted between battery cells to block the propagation of thermal runaway.

[0182] Alternatively, the fire-retardant sheet can have an asymmetric structure (e.g., L1-L2-L3 or L1-L3). In other words, it can be applied to lightweight models where heat diffusion and protection in only one direction are important, or where specific functions (e.g., thermal insulation) must be omitted.

[0183] Meanwhile, the fire retardant sheet according to the embodiment of the present invention may, of course, have an additional reinforcing layer. For example, aluminum foil 10 or a high-strength flame-retardant film (e.g., UL 94 V-0 grade 21) may be added to the outside of L3 to reflect radiant heat, thereby ensuring mechanical durability and radiant heat blocking function.

[0184] The aforementioned sheets can be manufactured by forming each layer into a flexible shape and then laminating them. Each layer of the sheet can be bonded through a lamination or press process. In this process, an insulating adhesive layer (e.g., silicone resin-based adhesive) with high temperature resistance and flame retardancy can be used to prevent delamination and electrical short circuits. Additionally, to prevent delamination in high-temperature vibration environments and to ensure durability, the adhesive strength may be increased by increasing surface roughness through chemical treatment (e.g., oxidation or plasma treatment) on the surfaces of L1, L2, and L3 prior to lamination. Furthermore, it is possible to realize a flexible yet tear-proof and robust structure by using high-strength fiber reinforcement and an optimized adhesive.

[0185] In addition, such a fire retardant sheet (5000) may be applied to the aforementioned pouch or case (or bag). The fire retardant sheet according to an embodiment of the present invention may be applied by manufacturing the multilayer composite sheet into a pouch or bag in the form of a flexible outer shell that accommodates a battery module or a single cell. This pouch may provide a function to prevent thermal runaway propagation and block flames / fragments. To function as a pouch layer with good thermal conductivity, the outer shell of the pouch or bag may be an extension of L3 or may be provided as L3 itself. By applying a high thermal conductivity layer to the outer shell of the pouch, heat diffused from within is rapidly transferred to the entire surface of the pouch and released to the external environment, thereby enhancing the overall cooling efficiency of the system. This can improve heat dissipation through external convection, particularly when attached to the outside of a battery module. Furthermore, a fire-resistant fiber fabric coated with a high thermal conductivity silicone resin layer or an aluminum / metal thin film may be used as the outer shell material of the pouch.

[0186] Meanwhile, since high-pressure gas is generated due to the activation of L1 and internal cell reactions when a battery runaway occurs, the pouch structure may be equipped with a pressure management (venting) function. For example, it may include a flame / fragment blocking vent structure. The pouch may have a structure that automatically opens or ruptures when the internal pressure rises above a critical threshold; in this process, it may include a flame barrier or reinforced thermal barrier coating structure that discharges high-pressure gas to the outside while blocking the leakage of generated flames and high-temperature particle blast forces to the outside or their propagation to adjacent cells. In conjunction with this, an active cooling system may be included, either independently or in combination with it. That is, it may include a cooling unit that stores an additional liquid extinguishing agent or phase change material inside the pouch and case (bag) in addition to L1, and releases it to rapidly cool the system upon reaching a critical temperature. This may provide a dual safety function involving L1 and the additional liquid extinguishing agent.

[0187] The fire retardant sheet according to an embodiment of the present invention may include L1, L2, and L3 functional layers individually or in various combinations. When L1 is used alone, only the fire extinguishing gel sheet (L1) is wrapped with a thin protective film to provide only the active fire extinguishing function with a minimum thickness.

[0188] Alternatively, L1 and L2 can be combined to focus on thermal insulation and active fire suppression functions. That is, by configuring it without the heat diffusion layer (L3), it can be utilized as a lightweight or cost-effective product.

[0189] Furthermore, by combining L1 and L3, fire suppression and high-speed heat diffusion / release can be focused without an insulation layer (L2), which can be applied where high heat release is important in the system design rather than insulation.

[0190] The fire-retardant sheet (5000) according to an embodiment of the present invention and the pouch and case (bag) including it can suppress thermal runaway and delay the thermal runaway phenomenon, while simultaneously suppressing the fire immediately through chemical and endothermic reactions. Furthermore, the ability to suppress the propagation of thermal runaway can be improved. In addition, by including a multilayer structure, insulation utilizing the low thermal conductivity of L2 ensures sufficient delay time for the propagation of thermal runaway, and during this delay time, the high-speed thermal discharge function of L3 allows heat to be dispersed. The mutually complementary action of these two layers can create a temperature and time environment in which L1 can operate effectively. Moreover, by introducing a vertical conductivity reinforcement structure to L3 to precisely control the heat transfer path, controlled thermal management beyond the function of a simple heat sink can be enabled. Furthermore, if a flame-retardant additive is included in the composition of L1 and a flexible yet high-strength composite material such as aerogel / PTFE is used in L2, the interlayer bonding strength is increased during lamination, thereby maintaining shape stability and durability even in unfavorable temperature environments and vibration conditions. This allows for easy fabrication and application in the form of flexible sheets, pouches, or cases that can follow the complex shape of battery cells.

[0191]

[0192] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0193] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

1. A pair of protective sheets coated with a flame-retardant material; and A fibrous member provided by coating or immersing the above flame-retardant material; comprising The above flame retardant material is, Digestible powder having at least one decomposition initiation temperature; and A secondary battery fire retardant sheet comprising an organic binder that disperses and fixes the above-mentioned fire-retardant powder.

2. In Paragraph 1, The above protective sheet is, A secondary battery fire retardant sheet composed of at least one of glass fiber, carbon fiber, basalt fiber, rock wool, and aramid fiber, and provided with a graphene coating.

3. In Paragraph 1, The above digestible powder is, A secondary battery fire retardant sheet comprising at least one of alkali metals, alkaline earth metals, and ammonium-based materials.

4. In Paragraph 3, The above-mentioned fire-retardant powder is an inorganic carbonate powder, a secondary battery fire-retardant sheet.

5. In Paragraph 3, The above alkali metal is, A secondary battery fire retardant sheet comprising one or more of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), and potassium bicarbonate (KHCO3).

6. In Paragraph 3, The above alkaline earth metals are, A secondary battery fire retardant sheet comprising one or more of magnesium bicarbonate (Mg(HCO3)2), magnesium carbonate (MgCO3), calcium carbonate (CaCO3) and calcium bicarbonate (Ca(HCO3)2).

7. In Paragraph 3, The above ammonium-based substance is, A secondary battery fire retardant sheet comprising one or more of ammonium carbonate ((NH4)2CO3) and ammonium bicarbonate (NH4HCO3).

8. In Paragraph 1, The above-mentioned digestive substance is, A secondary battery fire retardant sheet containing 60 to 95 weight percent of the above-mentioned flame retardant material per 1 weight part.

9. In Paragraph 1, The above organic binder is A secondary battery fire retardant sheet containing 5 to 40 weight percent based on 1 weight part of the above-mentioned flame retardant material.

10. Battery pack; A battery pack cover covering at least a portion of the battery pack; and It includes a secondary battery fire retardant sheet provided on the inner side of the battery pack cover to cover the battery; and The above secondary battery fire retardant sheet is, A pair of protective sheets coated with a flame-retardant material; and A fibrous member provided by coating or immersing the above flame-retardant material; comprising The above flame retardant material is, Digestible powder having at least one decomposition initiation temperature; and A secondary battery comprising an organic binder that disperses and fixes the above-mentioned flammable powder.

11. A main body that partitions a storage space and includes an opening and closing part; A cover capable of opening and closing the above-mentioned opening and closing part; and A extinguishing agent located within the above storage space, having one or more decomposition initiation temperatures, and comprising at least one of alkali metals, alkaline earth metals, and ammonium-based substances; Pouch.

12. In Paragraph 11, The opening / closing part and the cover include a welding material so that the cover can be welded to the opening / closing part in a high-temperature environment. Pouch.

13. In Paragraph 11, The above main body is a pouch comprising a one-way valve through which internal gas can be discharged to the outside.

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