Battery exterior surface coating agent composition for preventing thermal runaway of battery and battery

Abstract

This invention relates to a coating composition for the external surface of a battery for preventing thermal runaway, the coating composition comprising a thermally decomposable compound and a binder, the thermally decomposable compound being selected from carbonates, hydroxides, bicarbonates and combinations thereof, and the binder being selected from oil-based binders and water-based binders.

Description

Technical Field

[0001] This invention relates to a coating composition for the outer surface of a battery for preventing thermal runaway, and a battery thereof. The coating composition comprises a thermally decomposable compound and a binder, and is configured to be coated on the outer surface of the battery to form a coating, thereby providing effects such as heat absorption, preventing explosion, and reducing heat transfer in the event of thermal runaway of the battery. Background Technology

[0002] When a lithium-ion battery experiences thermal runaway, the internal temperature rises to over 1000°C. This causes the aluminum material, typically used for the battery casing, as well as Fe and SUS materials, to melt, thus accelerating thermal runaway of the surrounding battery due to leakage.

[0003] In particular, the ejection of ethylene carbonate (EC) and propylene carbonate (PC), which are commonly used as electrolytes, may generate sparks, which could be the cause of a battery explosion.

[0004] Furthermore, in the case of electric vehicles, when thermal runaway occurs, exposure to toxic gases due to the effects of hydrofluoric acid in the leaked fluid is necessary, so it is important to ensure escape time and reduce exposure to toxic gases.

[0005] As a prior art taking this into account, Korean Patent Publication No. 10-2022-0014844 (February 7, 2022) proposes a lithium battery thermal runaway inhibitor. However, the above-mentioned prior art releases a polar solution to transport metal ions and amphoteric metal ions to the lithium battery, where they react with the positive and negative active materials to transform into a lower energy state. Therefore, there is a limitation in the battery structure that a separation mechanism for releasing the polar solution must be added.

[0006] As another prior art, Korean Patent Publication No. 10-2023-0139263 (October 5, 2023) proposes a fire and thermal runaway barrier for electric vehicle batteries. However, the above-mentioned prior art is made into a flexible thermal runaway-proof sheet with tensile and heat insulation properties. Therefore, there is a limitation in the battery structure that the barrier must be attached.

[0007] As another prior art, Korean Patent No. 10-1518189 (April 29, 2015) proposes a structure to prevent the propagation of thermal runaway in a battery cell. However, the above-mentioned prior art provides a heat conductor that forms a conduction path to remove heat from the cell that has experienced thermal runaway and to disperse the heat to other cells in a way that prevents thermal runaway from occurring in cells near the faulty cell. Therefore, in terms of battery structure, there is a limitation that a first heat conduction bus and a second heat conduction bus made of metal must be added. Summary of the Invention

[0008] (a) Technical problems to be solved The present invention was made in view of the problems described above. The object of the present invention is to provide a coating composition for the outer surface of a battery for preventing thermal runaway of a battery, and a battery thereof. The coating composition comprises a thermally decomposable compound and a binder and is configured to be coated on the outer surface of the battery to form a coating, thereby providing heat absorption, preventing explosion, reducing heat transfer, and other effects when the battery experiences thermal runaway.

[0009] (II) Technical Solution According to one aspect of the present invention with regard to the above objectives, a coating composition for preventing thermal runaway of a battery is disclosed, the coating composition comprising a thermally decomposable compound and a binder, the thermally decomposable compound being selected from carbonates, hydroxides, bicarbonates and combinations thereof, and the binder being selected from oil-based binders and water-based binders.

[0010] Preferably, the carbonate is selected from BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

[0011] Preferably, the hydroxide is selected from Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

[0012] Preferably, the bicarbonate is selected from NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

[0013] Preferably, the oily adhesive contains a Si-O backbone in a cured state in an environment containing O2 or H2O.

[0014] Preferably, the oily adhesive is selected from siloxane adhesives and polysilazane adhesives.

[0015] Preferably, the water-based adhesive is selected from water glass and colloidal silica-based adhesives.

[0016] Preferably, the content of the thermally decomposable compound is 50-90 parts by weight per 100 parts by weight of the total composition.

[0017] According to another aspect of the invention, a battery is disclosed having a coating formed on its outer surface, the coating being formed by a coating agent composition on the outer surface of the battery for preventing thermal runaway.

[0018] Preferably, the coating has a thickness of 10-500 μm.

[0019] Preferably, the battery is a lithium-ion battery.

[0020] (III) Beneficial Effects The present invention, as described above, comprises a thermally decomposable compound and a binder, and is configured to be coated on the outer surface of a battery to form a coating, thereby providing effects such as heat absorption, preventing explosion, and reducing heat transfer in the event of thermal runaway of the battery.

[0021] In particular, the present invention is made and coated on the surface of the battery casing in the form of a coating agent, thus having the advantage of providing battery thermal runaway prevention effect without changing the internal structure of the battery. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a battery according to an embodiment of the present invention. Figure 2 This is a graph showing the heat transfer characteristics and mass variation of CaCO3, a carbonate compound, as a thermally decomposable compound, with temperature. Detailed Implementation

[0023] The battery coating composition of the present invention for preventing thermal runaway is particularly suitable for forming coatings that prevent thermal runaway in lithium-ion batteries. However, the use of the battery coating composition of the present invention is not limited to lithium-ion batteries, but can also be used to form coatings for other types of batteries that experience thermal runaway similar to that of lithium-ion batteries.

[0024] Examples of embodiments of the coating composition for lithium-ion batteries of the present invention will be described, focusing on such a composition. The present invention is not limited to the following embodiments, and it should be understood that various modifications can be made by those skilled in the art.

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of a battery according to an embodiment of the present invention. Figure 2 This is a graph showing the heat transfer characteristics and mass variation of CaCO3, a carbonate compound, as a thermally decomposable compound, with temperature.

[0027] The battery coating composition of the present invention comprises a thermally decomposable compound and a binder, wherein the thermally decomposable compound is selected from carbonates, hydroxides, bicarbonates and combinations thereof, and the binder is selected from oil-based binders and water-based binders.

[0028] In this invention, as a preferred example, the carbonate may be selected from BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

[0029] Carbonates are salts in which the hydrogen atoms of carbonic acid are replaced by metals; they contain carbonate ions (CO3-). 2 - Ionic crystals.

[0030] The advantages of carbonates are that they do not produce explosive substances after thermal decomposition, the endothermic reaction during thermal decomposition is relatively large, and they are relatively inexpensive.

[0031] Table 1 shows the main physical properties of the carbonates applicable to this invention, including decomposition temperature (°C) and heat of decomposition (kJ / mol).

[0032] [Table 1] In this invention, as a preferred example, the hydroxide may be selected from Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

[0033] Hydroxides are compounds containing a hydroxyl group (-OH), and are generally limited to referring to metal hydroxides. The general formula has M... n (OH) m The structure of (M is a metal).

[0034] Hydroxides, especially Al(OH)3, have low thermal conductivity.

[0035] Table 2 shows the main physical properties of the hydroxides applicable to this invention, including decomposition temperature (°C) and heat of decomposition (kJ / mol).

[0036] [Table 2] In this invention, as a preferred example, the bicarbonate may be selected from NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

[0037] Bicarbonate is a salt formed when one of the two hydrogen atoms in carbonic acid (H₂CO₃) is replaced by a metal atom. - Salts of ions, generally having the structure MHCO3 (M is a metal).

[0038] Bicarbonates have a low decomposition temperature, so they can be addressed in the early stages of thermal runaway.

[0039] Table 3 shows the main physical properties of the bicarbonate applicable to this invention, including decomposition temperature (°C) and heat of decomposition (kJ / mol).

[0040] [Table 3] The thermally decomposable compound of the present invention forms a coating on the outer surface of the battery and undergoes thermal decomposition at high temperatures during thermal runaway. As an example, the outer surface of the battery can be the outer surface of a single battery cell, the outer surface of a battery module, or the outer surface of a battery pack.

[0041] In this process, thermally decomposable compounds can prevent thermal runaway by absorbing heat from the decomposition of energy.

[0042] As an example, the following endothermic reaction can occur in the case of CaCO3 and MgCO3 in carbonates.

[0043] CaCO3(s) → CaO(s) + CO2(g) MgCO3(s) → MgO(s) + CO2(g) Figure 2 This is a graph showing the heat transfer characteristics and mass variation of CaCO3 with temperature.

[0044] As another example, in the case of 2Al(OH)3 and Ca(OH)2 in hydroxides, the following endothermic reaction can occur.

[0045] 2Al(OH)3→Al2O3+3H2O Ca(OH)₂→CaO+H₂O As another example, in the case of NaHCO3 and KHCO3 in bicarbonates, the following endothermic reaction can occur.

[0046] 2NaHCO3 → Na2CO3 + CO2 + H2O 2KHCO3 → K2CO3 + CO2 + H2O In addition, the thermal decomposition compound can prevent an explosion caused by the generation of sparks through thermal decomposition products (such as CO2).

[0047] In addition, the thermal decomposition compound can hinder heat transfer to adjacent batteries through the foaming effect of the gas generated during thermal decomposition.

[0048] For example, in the case of CaCO3 and MgCO3 in carbonates, during the above-mentioned endothermic reaction, CO3 in the solid is transformed into gaseous CO2, resulting in volume expansion. In addition, the Si component contained in the binder is also transformed into silicon oxide through decomposition (generating heat), and glazing (adding Ca, etc., reducing the glazing temperature) occurs, thereby generating ductility. The foaming effect is provided by the effect of the generated gas and the softened binder. Hydroxides provide a foaming effect through H2O, and bicarbonates provide a foaming effect through CO2 and H2O.

[0049] Particularly, in the case of a lithium-ion battery, LiPF6 used as an electrolyte may decompose at high temperature during thermal runaway, becoming a source of F, and react with surrounding water to generate toxic gas HF. The thermal decomposition products of the thermal decomposition compound react with HF for absorption, thereby reducing the release of toxic gas.

[0050] As an example, in the case of CaCO3 in carbonates, as described above, CaO is generated during the endothermic reaction, and as shown below, CaO can be absorbed through the reaction with HF, thereby reducing the release of toxic gas.

[0051] <CaO reaction (in the presence of SiO2 catalyst)> 4HF + 2H2O + 2CaO + SiO2 → 2CaF2 + SiO2 + 4H2O In addition, in the absence of a SiO2 catalyst, the following reaction occurs.

[0052] <CaO reaction (in the absence of SiO2 catalyst)> 4HF + 2H2O + 2CaO → CaF2 + 2HF + Ca(OH)2 + 2H2O [CaO + 2HF → CaF2 + H2O CaO + 2HF + 2H2O → Ca(OH)2 + 2HF + H2O] Referring to the above reaction formula, in the absence of a SiO2 catalyst, intermediate reaction processes occur, which may not be conducive to the rapid removal of HF. Considering this, it is preferable to use Si-based materials as the adhesives in the present invention.

[0053] As another example, in the case of MgCO3 in carbonate, as described above, MgO is generated during the endothermic reaction process. As shown below, MgO can absorb HF through the reaction, thereby reducing the release of toxic gases.

[0054] <MgO reaction (in the presence of a SiO2 catalyst)> 4HF + 2H2O + 2MgO → MgF2 + SiO2 + 4H2O In addition, the thermal decomposition products of the thermal decomposition compound react with the surrounding moisture, thereby providing an effect of delaying the thermal runaway of the battery caused by moisture.

[0055] As described above, in order to reduce the toxic gas HF, it is preferable to use CaCO3 and / or MgCO3 as the thermal decomposition compound.

[0056] As an example, in the case of CaCO3 in carbonate, as described above, CaO is generated during the endothermic process. As shown below, CaO can react with the surrounding moisture, thereby providing an effect of delaying the thermal runaway of the battery caused by moisture.

[0057] <CaO reaction> CaO(s) + H2O(l) → Ca(OH)2(aq, s) Utilizing the above effects, for example, when a thermal runaway of the battery occurs in a vehicle or an Energy Storage System (ESS) device, etc., the escape time of the driver or operator can be ensured.

[0058] The thermal decomposition compound of the present invention can be appropriately selected according to the housing material of the battery for which the coating is to be formed. As an example, in the case of a 4680 battery (a cylindrical battery with a diameter of 46 mm and a length of 80 mm) whose outer battery housing is made of materials such as SUS and Fe, it is preferable to select a thermal decomposition compound with a decomposition temperature of 300 °C or higher. For example, the melting temperature of the SUS material is about 1400 °C, so it is preferable to select a thermal decomposition compound with a relatively high decomposition temperature of 300 °C or higher.

[0059] In the case where the outer battery housing is made of Al material or in the form of a pouch, a thermal decomposition compound with a decomposition temperature corresponding to the conditions can be selected. As an example, in the case where the outer battery housing is made of Al material or in the form of a pouch, hydroxides and / or bicarbonates can be selected as the thermal decomposition compound.

[0060] For example, the melting temperature of Al materials is below 600°C, and the melting temperature of flexible packaging is also below that temperature. Therefore, hydroxides and / or bicarbonates with relatively lower decomposition temperatures than carbonates can be selected.

[0061] That is, for the thermal decomposition compounds of the present invention, it is preferable to select thermal decomposition compounds whose decomposition temperature is lower than the melting temperature of the external battery material.

[0062] Preferably, the thermally decomposable compounds of the present invention should be poorly soluble in organic solvents or water, and be harmless to the human body and environmentally friendly.

[0063] In addition, as a preferred example in this invention, the oily adhesive may contain a Si-O backbone in a state where it is cured in an environment containing O2 or H2O.

[0064] In this invention, as a preferred example, the oily adhesive may be selected from siloxane adhesives and polysilazane adhesives.

[0065] Siloxanes are a general term for compounds containing Si-O bonds (siloxane bonds) that are composed of silicon, oxygen, and hydrogen.

[0066] Siloxanes are derived from the general formula H3SiO (H2SiO). n SiH3, (-H2SiO-) n The terms "etc." indicate that substances in which all or part of the H groups are substituted with hydrocarbon functional groups such as alkyl (e.g., methyl), allyl, aryl (e.g., phenyl), vinyl, etc., or are substituted with hydroxyl (-OH) groups, are included in the siloxanes of the present invention.

[0067] Siloxanes contain Si-O bonds (siloxane bonds), so they can contain a Si-O backbone in the cured state.

[0068] As an example, silicone adhesives include methyl, phenyl, and silsesquioxane types, with products such as Momentive's TSR117, YR3370, TSR140, and 145.

[0069] Siloxane adhesives are inexpensive and widely available commercially. Siloxane adhesives can help remove HF by generating SiO2 at high temperatures.

[0070] Polysilazane is a polymer whose main chain is composed of -Si-N- bonds (silazane structure). During high-temperature heat treatment or humid heat treatment, polysilazane readily reacts with the surrounding O2 or H2O, transforming into SiO2 with glass-like properties through thermal decomposition or hydrolysis. Therefore, it can contain the Si-O main chain in a state that can be cured in an environment containing O2 or H2O.

[0071] Polysilazanes include hydrophilic inorganic polysilazanes (PHPS) and hydrophobic organic polysilazanes (OPSZ).

[0072] As an example, polysilazane adhesives include methyl and vinyl types, with products such as Merck's Durazane 1500 and 1800.

[0073] Polysilazane adhesives can be formulated as solvent-free products.

[0074] Compared to water-based adhesives, the oil-based adhesives exhibit superior spreadability during application.

[0075] In this invention, as a preferred example, the water-based adhesive may be selected from water glass and colloidal silica-based adhesives.

[0076] Water glass is an aqueous solution of sodium silicate obtained by melting silicon dioxide and alkali. It has high viscosity and is transparent, and is used in heat-resistant adhesives, self-hardening mold binders, and other applications.

[0077] As an example, water glass includes potassium silicate, lithium silicate, and sodium silicate, and products include YOUNG IL Chemicals' SFR-0582, ECO-M500, R-501, SMC-374-1, PS-C200, etc.

[0078] Colloidal silica is a substance formed by dispersing spherical, amorphous, non-porous colloidal silica particles in aqueous or organic solutions. - The ions form siloxane bonds (Si-O-Si) inside, thus exhibiting characteristics such as binding, heat resistance, film formation, and adsorption.

[0079] As an example, colloidal silica-based adhesives come in various types depending on how the binder is added, with products including YOUNG IL Chemicals' NH-64U-1, etc.

[0080] In the case of water glass or colloidal silica-based adhesives, the cured material is easily affected by moisture. Therefore, it is preferable to add SiO2 or Al2O3, adjusting the molar ratio with K and Na to be more than 2 and less than 5. The proportions of alkali metals and SiO2 vary in each adhesive material, thus requiring appropriate addition.

[0081] The water-based adhesive uses water during application, thus generating fewer harmful substances and readily glazing at high temperatures. However, compared to oil-based adhesives, water-based adhesives have poorer spreadability, making them preferable for priming.

[0082] In this invention, as a preferred example, the content of the thermally decomposable compound may be 50-90 parts by weight per 100 parts by weight of the total composition.

[0083] When the content of thermally decomposable compounds is less than 50 parts by weight, it is not sufficient to provide the effect of preventing thermal runaway by endothermic energy decomposition. When the content of thermally decomposable compounds is greater than 90 parts by weight, the bonding properties of the adhesive are reduced, making it difficult to ensure adhesion to the battery.

[0084] Reference Figure 1 The outer surface of the battery B of the present invention is formed with a coating C, which is formed by the battery coating composition. As a preferred example, the battery coating composition of the present invention can be applied to the outer surface of the battery instead of a protective organic material (cover sheet). As an example, the coating can be performed by spraying or dipping. As another example, the coating of this embodiment can include potting coating, and can include methods such as fabricating a sheet containing the battery coating composition of this embodiment and attaching it to the outer surface of the battery. The coating of this embodiment can include various known methods of forming a composition layer on the outer surface of the battery.

[0085] In this invention, as a preferred example, the coating C can have a thickness of 10-500 μm.

[0086] When the thickness of coating C is less than 10 μm, the heat absorption effect of the present invention is insufficient, and from the perspective of the deviation of the actual coating thickness, the problem of thickness uniformity may also occur.

[0087] When the thickness of coating C is greater than 500 μm, the module size may increase during battery module manufacturing.

[0088] In this invention, as a preferred embodiment, the battery B can be a lithium-ion battery. As an example, a cylindrical lithium-ion battery has the following structure: a wound electrode plate is disposed inside a can, which serves as a cylindrical shell, with a positive electrode and a negative electrode respectively disposed at both ends of the can; the coating C of this invention can be formed on the outer side of the can.

[0089] The battery coating composition according to the present invention can be manufactured by the following method.

[0090] It can be manufactured by weighing thermally decomposable compounds in powder form, weighing binders in liquid or solid form, and mixing them by ball milling or homogenizing.

[0091] Water-based adhesives are typically supplied in liquid form, while oil-based adhesives are supplied in either liquid or solid form. As an example, polysilazane adhesives are supplied in liquid form.

[0092] When mixing thermally decomposable compounds with binders, a dispersing material may be included. As an example, phosphate-based polyesters can be used as dispersing materials.

[0093] The following shows various embodiments of the battery coating composition of the present invention and the oxygen torch evaluation results of these embodiments (see Table 4).

[0094] <Example 1> A coating composition was prepared by mixing 100 parts by weight of Durazane 1500 as a binder, 680 parts by weight of CaCO3 as a thermal decomposition compound, and 4 parts by weight of a dispersant. The coating composition was then coated onto a metal sheet with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0095] As an evaluation result of the oxygen torch for the coating composition for batteries, the measured melting time was 15 seconds.

[0096] Oxygen torch evaluation is an evaluation method that measures the time required for a coated metal sheet to melt and form a hole when a gas torch at approximately 1400°C is used to spray a flame onto the object, thereby comparing its heat resistance. Oxygen torch evaluation can be used to assess the delay time required for a battery to experience thermal runaway.

[0097] <Example 2> A coating composition was prepared by mixing 100 parts by weight of Durazane 1500 as a binder, 560 parts by weight of MgCO3 as a thermal decomposition compound, and 3 parts by weight of a dispersant. The coating composition was then coated onto a metal sheet with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0098] As an evaluation result of the oxygen torch of the coating composition for batteries, the measured melting time was 30 seconds.

[0099] <Example 3> A coating composition was prepared by mixing 200 parts by weight of TSR 117 as a binder, 680 parts by weight of CaCO3 as a thermal decomposition compound, and 4 parts by weight of a dispersant. The coating composition was then coated onto a metal sheet with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0100] As an evaluation result of the oxygen torch for the coating composition for batteries, the measured melting time was 14 seconds.

[0101] <Example 4> A coating composition was prepared by mixing 200 parts by weight of TSR 117 as a binder, 300 parts by weight of MgCO3 and 250 parts by weight of CaCO3 as thermal decomposition compounds, and 3 parts by weight of a dispersing material. The coating composition was then coated onto a metal plate with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0102] As an evaluation result of the oxygen torch of the coating composition for batteries, the measured melting time was 23 seconds.

[0103] <Example 5> A coating composition was prepared by mixing 370 parts by weight of SFR-0582 as a binder, 680 parts by weight of CaCO3 as a thermal decomposition compound, and 4 parts by weight of a dispersant. The coating composition was then coated onto a metal sheet with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0104] As an evaluation result of the oxygen torch for the coating composition for batteries, the measured melting time was 16 seconds.

[0105] <Example 6> A coating composition was prepared by mixing 370 parts by weight of SFR-0582 as a binder, 560 parts by weight of MgCO3 as a thermal decomposition compound, and 4 parts by weight of a dispersant. The coating composition was then coated onto a metal sheet with a thickness of 0.5t to form a coating with a thickness of 50μm.

[0106] As an evaluation result of the oxygen torch for the coating composition for batteries, the measured melting time was 29 seconds.

[0107] [Table 4] (The content of each component in the examples is by weight.) <Evaluation Results> As an evaluation result of the oxygen torch, if the melting time is 9 seconds or more (reference), it can be considered that it can provide heat absorption, prevent explosion, and reduce heat transfer when the battery experiences thermal runaway.

[0108] It can be confirmed that the melting time in the oxygen torch evaluation results of the battery coating compositions of Examples 1 to 6 is 9 seconds or more (reference), which can provide good heat absorption, prevent explosion and reduce heat transfer.

[0109] The embodiments presented above are exemplary. Those skilled in the art can make various modifications and variations to the proposed embodiments without departing from the spirit and scope of the invention. The scope of the invention is not limited by these modifications and variations.

Claims

1. A coating composition for preventing thermal runaway of a battery on its external surface, comprising a thermally decomposable compound and a binder. The thermally decomposable compounds are selected from carbonates, hydroxides, bicarbonates, and combinations thereof. The adhesive is selected from oil-based adhesives and water-based adhesives.

2. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, wherein, The carbonate is selected from BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

3. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, wherein, The hydroxide is selected from Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

4. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, wherein, The bicarbonate is selected from NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

5. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, characterized by, The oily adhesive contains a Si-O backbone in a cured state in an environment containing O2 or H2O.

6. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, characterized by, The oily adhesive is selected from siloxane adhesives and polysilazane adhesives.

7. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, characterized by, The water-based adhesive is selected from water glass and colloidal silica-based adhesives.

8. The coating agent composition for the outer surface of a battery for preventing thermal runaway of a battery according to claim 1, characterized by, The thermally decomposable compound is present in the amount of 50-90 parts by weight per 100 parts by weight of the total composition.

9. A battery having a coating formed on its outer surface, said coating being formed by a battery outer surface coating composition for preventing thermal runaway of the battery as described in any one of claims 1 to 8.

10. The battery of claim 9, wherein, The coating has a thickness of 10-500 μm.

11. The battery of claim 9, wherein, The battery is a lithium-ion battery.

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