Coating composition for outer surface of battery, for preventing thermal runaway of battery, and battery

Abstract

The present invention relates to a coating composition for the outer surface of a battery, for preventing thermal runaway of the battery, the composition comprising: a pyrolytic compound selected from the group consisting of carbonates, hydroxides, hydrogen carbonates, and combinations thereof; and a binder selected from the group consisting of an oily binder and an aqueous binder.

Description

Coating composition for the outer surface of a battery to prevent thermal runaway of a battery, battery

[0001] The present invention relates to a coating composition for the outer surface of a battery for preventing thermal runaway of a battery, and to a battery, comprising a pyrolysis compound and a binder and configured to be applied to the outer surface of a battery to form a coating layer, thereby providing effects such as heat absorption, explosion prevention, and heat transfer reduction during thermal runaway of a battery.

[0002]

[0003] When a lithium-ion battery experiences thermal runaway, its internal temperature can rise above 1,000°C. This can melt not only aluminum, but also iron and stainless steel (SUS) materials commonly used in battery cases, accelerating thermal runaway in surrounding batteries due to fluid leakage.

[0004] In particular, EC (Ethylene carbonate) and PC (Propylene carbonate), which are commonly used as electrolytes, may be ejected, causing a battery explosion due to sparks.

[0005] In addition, in the case of electric vehicles, it is necessary to secure escape time and reduce toxic gases, such as exposure to toxic gases due to thermal runaway or hydrofluoric acid leakage.

[0006] Considering this, as a prior art, Korean Patent Publication No. 10-2022-0014844 (2022.02.07) proposed a thermal runaway suppressor for lithium batteries. However, the prior art discharges a polar solution to transport metal ions and zwitterionic metal ions into the lithium battery and reacts with the positive and negative active materials to transfer them to a state with lower energy. Therefore, there was a limitation in that a separation mechanism for discharging the polar solution had to be added in terms of the structural aspect of the battery.

[0007] As another prior art, Korean Patent Publication No. 10-2023-0139263 (2023.10.05) proposed a battery fire and thermal runaway blocking sheet for electric vehicles. However, since the prior art is manufactured in the form of a flexible thermal runaway prevention sheet with anti-tensile properties and heat blocking properties, there was a limitation in that the blocking sheet had to be attached and installed from a structural aspect of the battery.

[0008] As another prior art, Korean Patent No. 10-1518189 (April 29, 2015) proposed a structure for preventing the propagation of thermal runaway of cells within a battery. However, the prior art provided a heat conductor that forms a conduction path that draws heat from a cell experiencing thermal runaway and distributes the heat to other cells in a manner that prevents thermal runaway from being triggered in cells near the faulty cell. Therefore, there was a limitation in that a first heat bus and a second heat bus made of metal had to be added in terms of the structural aspect of the battery.

[0009]

[0010] The present invention has been devised in consideration of the above problems, and the purpose of the present invention is to provide a battery, a coating composition for the outer surface of a battery for preventing thermal runaway of a battery, which comprises a pyrolysis compound and a binder and is configured to be applied to the outer surface of a battery to form a coating layer, thereby providing effects such as heat absorption, explosion prevention, and heat transfer reduction during thermal runaway of the battery.

[0011]

[0012] According to one aspect of the present invention in view of the above objects, a coating composition for an external surface of a battery for preventing thermal runaway of a battery is disclosed, which comprises a pyrolysis compound selected from the group consisting of carbonates, hydroxides, bicarbonates and combinations thereof, and a binder selected from the group consisting of oily binders and water-based binders.

[0013] Preferably, the carbonate is selected from the group consisting of BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

[0014] Preferably, the hydroxide is selected from the group consisting of Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

[0015] Preferably, the bicarbonate is selected from the group consisting of NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

[0016] Preferably, the above-mentioned oily binder comprises a Si-O backbone in a cured state in an environment containing O2 or H2O.

[0017] Preferably, the above-mentioned oily binder is selected from the group consisting of a siloxane series binder and a polysilazane series binder.

[0018] Preferably, the aqueous binder is selected from the group consisting of water glass and colloidal silica based binders.

[0019] Preferably, the pyrolysis compound is included in an amount of 50 to 90 parts by weight per 100 parts by weight of the total composition.

[0020] According to another aspect of the present invention, a battery is disclosed in which a coating layer is formed on the outer surface of the battery using a coating composition for preventing thermal runaway of the battery.

[0021] Preferably, the coating layer has a thickness of 10 to 500 μm.

[0022] Preferably, the battery is a lithium-ion battery.

[0023]

[0024] The present invention includes a pyrolysis compound and a binder and is configured to be applied to the outer surface of a battery to form a coating layer, thereby providing effects such as heat absorption, explosion prevention, and heat transfer reduction during thermal runaway of the battery.

[0025] In particular, the present invention has the advantage of providing a thermal runaway prevention effect of a battery without changing the internal structure of the battery, since it is produced in the form of a coating agent and applied to the surface of a battery case.

[0026]

[0027] Figure 1 is a schematic diagram of a battery according to an embodiment of the present invention;

[0028] Figure 2 is a graph showing the heat transfer characteristics and mass change according to temperature change of CaCO3, a carbonate, which is a pyrolysis compound.

[0029]

[0030] The coating composition for the outer surface of a battery for preventing thermal runaway of the battery of the present invention is particularly useful for forming a coating layer for preventing thermal runaway of a lithium-ion battery. However, the battery coating composition of the present invention is not necessarily limited to use in lithium-ion batteries, and may also be used to form a coating layer for other types of batteries that experience thermal runaway similar to lithium-ion batteries.

[0031] Examples of the battery coating composition of the present invention will be described with a focus on a lithium-ion battery coating composition. It will be understood that the present invention is not limited to the following examples, and that various modifications are possible by those skilled in the art.

[0032]

[0033] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0034] Fig. 1 is a schematic diagram of a battery according to an embodiment of the present invention, and Fig. 2 is a graph showing heat transfer characteristics and mass change according to temperature change of CaCO3, a carbonate, which is a pyrolysis compound.

[0035] The coating composition for a battery of the present invention comprises a pyrolysis compound selected from the group consisting of carbonates, hydroxides, hydrogen carbonates and combinations thereof, and a binder selected from the group consisting of oily binders and water-based binders.

[0036] As a preferred example in the present invention, the carbonate may be selected from the group consisting of BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

[0037] Carbonate is a salt in which the hydrogen of carbonic acid is replaced by a metal, carbonate ion CO3 2 - is an ionic crystal containing .

[0038] Carbonates have the advantages of not producing substances that contribute to explosion after pyrolysis, having a relatively large amount of endothermic reaction during the pyrolysis process, and being relatively inexpensive.

[0039] The main properties of carbonates applicable to the present invention, including decomposition temperature (℃) and decomposition heat (kJ / mol), can be seen in Table 1.

[0040] Substance Decomposition temperature (℃) Decomposition heat (kJ / mol) Density (g / cm³) Thermal conductivity (W / m K) BeCO3 300 134.4 2.9 1.3 CaCO3 (aragonite) 470 179.2 2.9 3 1.5 Li2CO3 700 104.6 1.0 5 0.8 MgCO3 350 1172.9 3 1.3 SrCO3 1100 235 3.7 1.3 Na2CO3 500 94.7 2.5 3 0.6 K2CO3 500 94.7 2.6 5 0.5 CaCO3 (calcite) 840 1782.7 11.4 BaCO3 1740 2674.2 2 1.6 RaCO3 1100 126.13 1.3

[0041] As a preferred example in the present invention, the hydroxide may be selected from the group consisting of Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

[0042] Hydroxides are compounds containing a hydroxyl group (-OH), and are generally used only for metal hydroxides. The general formula is Mn(OH)m (M is metal).

[0043] Among hydroxides, Al(OH)3 in particular has low thermal conductivity.

[0044] The main properties of hydroxides applicable to the present invention, including decomposition temperature (℃) and decomposition heat (kJ / mol), can be seen in Table 2.

[0045] Substance Decomposition temperature (℃) Decomposition heat (kJ / mol) Density (g / cm³) Thermal conductivity (W / m K) Be(OH) 2375 292.8 2.48 0.4 Mg(OH) 233 2812.37 2.4 Al(OH) 3180 108 3.09 0.3 Ca(OH) 2520~580 109 2.21 1.4 Sr(OH) 2500~850 199 2.75 1.4 Ba(OH) 2780~800 2623.76 1.5

[0046] As a preferred example in the present invention, the bicarbonate may be selected from the group consisting of NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

[0047] Bicarbonate is a salt formed when one of the two hydrogen atoms of carbonic acid (H2CO3) is replaced by a metal atom. It is a salt of HCO3- ion and has the general formula MHCO3 (M is a metal).

[0048] Bicarbonate has a low decomposition temperature, allowing for early response when thermal runaway occurs.

[0049] The main properties of bicarbonate salts applicable to the present invention, including decomposition temperature (℃) and decomposition heat (kJ / mol), can be seen in Table 3.

[0050] Substance Decomposition temperature (℃) Decomposition heat (kJ / mol) Density (g / cm³) Thermal conductivity (W / m K) NaHCO3 270 10.6 2.18 0.8 KHCO3 260 10.22 22 0.8 Ca(HCO3) 2180 14.11 47 1.2 Mg(HCO3) 2100 12.9 1.6 1.2 LiHCO3 130 12.5 1.04 0.8 Sr(HCO3) 2160 14.12 18 1.2 Ba(HCO3) 2180 15.7 2.5 21.2 NH4HCO3 170 14.11 2 0.6

[0051] The pyrolytic compound of the present invention forms a coating layer on the external surface of a battery, thereby causing thermal decomposition due to high temperatures during thermal runaway. For example, the external surface of the battery may be the external surface of a battery cell, the external surface of a battery module, or the external surface of a battery package.

[0052] In this process, the pyrolysis compound can prevent thermal runaway by absorbing the decomposition energy.

[0053] For example, in the case of carbonates such as CaCO3 and MgCO3, an endothermic reaction can occur as follows.

[0054] CaCO3(s) → CaO(s) + CO2(g)

[0055] MgCO3(s) → MgO(s) + CO2(g)

[0056] Figure 2 shows the heat transfer characteristics and mass change according to temperature change of CaCO3.

[0057] As another example, in the case of hydroxides 2Al(OH)3 and Ca(OH)2, an endothermic reaction can occur as follows.

[0058] 2Al(OH)3→ Al2O3+ 3H2O

[0059] Ca(OH)2→ CaO + H2O

[0060] As another example, in the case of bicarbonate salts such as NaHCO3 and KHCO3, an endothermic reaction can occur as follows.

[0061] 2NaHCO3→ Na2CO3+ CO2+ H2O

[0062] 2KHCO3→ K2CO3+ CO2+ H2O

[0063] Additionally, the pyrolysis compound can prevent explosions due to spark generation through the pyrolyzed substance (e.g., CO2).

[0064] Additionally, pyrolysis compounds may impede heat transfer to adjacent batteries due to the foaming effect of gases generated during pyrolysis.

[0065] For example, in the case of CaCO3 and MgCO3 among carbonates, the volume expands as the CO3 in the solid changes into gaseous CO2 during the endothermic reaction. In addition, the Si component included in the binder also changes into silicon oxide through decomposition (heat generation), and the glaze (Ca, etc. are added and the glaze temperature is lowered) generates ductility. The foaming effect is provided by the effect of the generated gas and the softened binder. Hydroxide provides a foaming effect through H2O, and bicarbonate provides a foaming effect through CO2 and H2O.

[0066] In particular, in the case of lithium-ion batteries, LiPF6 used as an electrolyte can become a source of F when it decomposes at high temperatures during thermal runaway and reacts with surrounding water to produce HF, a toxic gas. However, the emission of toxic gases can be reduced by absorption through the reaction between the thermally decomposed material of the thermal decomposition compound and HF.

[0067] For example, in the case of CaCO3 among carbonates, CaO is generated in the endothermic reaction process as described above, and CaO can reduce the emission of toxic gases by absorption through reaction with HF as shown below.

[0068] < CaO reaction (in the presence of SiO2 catalyst) >

[0069] 4HF + 2H2O + 2CaO + SiO2→ 2CaF2+ SiO2+ 4H2O

[0070] Meanwhile, in the absence of a SiO2 catalyst, the following reaction occurs.

[0071] < CaO reaction (without SiO2 catalyst) >

[0072] 4HF + 2H2O + 2CaO → CaF2+ 2HF + Ca(OH)2+ 2H2O

[0073] [CaO + 2HF → CaF2+ H2O

[0074] CaO + 2HF + 2H2O → Ca(OH)2+ 2HF + H2O]

[0075] Referring to the above reaction formula, if there is no SiO2 catalyst, an intermediate reaction process is involved, which may be disadvantageous for rapid HF removal. In consideration of this, it is preferable to use a Si-based binder in the present invention.

[0076] As another example, in the case of MgCO3 among carbonates, MgO is generated in the endothermic reaction process as described above, and MgO can reduce the emission of toxic gases by absorption through reaction with HF as shown below.

[0077] < MgO reaction (in the presence of SiO2 catalyst) >

[0078] 4HF + 2H2O + 2MgO → MgF2+ SiO2+ 4H2O

[0079] Additionally, the pyrolyzed material of the pyrolysis compound reacts with surrounding moisture, providing an effect of delaying moisture-induced battery thermal runaway.

[0080] As described above, in order to reduce HF, a toxic gas, it is desirable to use CaCO3 and / or MgCO3 as thermal decomposition compounds.

[0081] For example, in the case of CaCO3 among carbonates, CaO is generated during the heat absorption process as described above, and CaO can react with surrounding moisture as shown below to provide an effect of delaying battery thermal runaway caused by moisture.

[0082] < CaO reaction >

[0083] CaO(s) + H2O(l) → Ca(OH)2(aq,s)

[0084] By utilizing the above effects, it is possible to secure escape time for drivers or workers in the event of battery thermal runaway, for example, in vehicles or ESS (Energy Storage System) facilities.

[0085] The pyrolysis compound of the present invention can be appropriately selected depending on the battery case material for which the coating layer is to be formed. For 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 case is composed of materials such as SUS and Fe, it is preferable to select a pyrolysis compound having a decomposition temperature of 300°C or higher. For example, since SUS material has a melting temperature of approximately 1400°C, it is preferable to select a pyrolysis compound having a relatively high decomposition temperature of 300°C or higher.

[0086] If the exterior of the battery case is composed of an aluminum material or is configured in a pouch form, a thermal decomposition compound having a corresponding decomposition temperature may be selected. For example, if the exterior of the battery case is composed of an aluminum material or is configured in a pouch form, a hydroxide and / or bicarbonate may be selected as the thermal decomposition compound.

[0087] For example, since Al material has a melting temperature of less than 600°C and the pouch has a melting temperature lower than this, a hydroxide and / or hydrogen carbonate having a relatively lower decomposition temperature than a carbonate can be selected.

[0088] That is, it is preferable that the pyrolysis compound of the present invention be selected so that its decomposition temperature is lower than the melting temperature of the external material of the battery.

[0089] Preferably, the pyrolysis compound of the present invention should not be easily dissolved in organic solvents or water, and should be harmless to the human body and environmentally friendly.

[0090] Meanwhile, as a preferred example in the present invention, the oil-based binder may include a Si-O backbone in a cured state in an environment containing O2 or H2O.

[0091] As a preferred example in the present invention, the oil-based binder may be selected from the group consisting of a siloxane-based binder and a polysilazane-based binder.

[0092] Siloxane is a general term for compounds that contain Si-O bonds (siloxane bonds) and are composed of silicon, oxygen, and hydrogen.

[0093] Siloxane is represented by the general formula H3SiO(H2SiO)nSiH3, (-H2SiO-)n, etc., and those in which all or part of H is replaced with a hydrocarbon functional group such as an alkyl group (e.g., a methyl group), an allyl group, an aryl group (e.g., a phenyl group), a vinyl group, or a hydroxyl group (-OH) are included in the siloxane series of the present invention.

[0094] Since siloxane contains Si-O bonds (siloxane bonds), it can contain a Si-O backbone in a cured state.

[0095] For example, siloxane series binders include methyl, phenyl, and silsesquioxane, and products include Momentive's TSR117, YR3370, TSR140, and 145.

[0096] Siloxane-based binders are inexpensive, widely available, and can help remove HF by generating SiO2 at high temperatures.

[0097] Polysilazane is a polymer whose backbone is a -Si-N- bond (silazane structure). Polysilazane readily reacts with surrounding O2 or H2O during high-temperature heat treatment or wet heat treatment, and is converted to SiO2 with glass-like properties through thermal decomposition or hydrolysis. Therefore, it can contain a Si-O backbone in a cured state in an environment containing O2 or H2O.

[0098] Polysilazane includes hydrophilic inorganic polysilazane (PHPS) and hydrophobic organic polysilazane (OPSZ).

[0099]

[0100] For example, polysilazane series binders include methyl and vinyl series, and products include Durazane 1500 and 1800 from Merk.

[0101] Polysilazane series binders can be produced in a non-woven type.

[0102] The above-mentioned oil-based binder has better spreadability when applying a coating compared to a water-based binder.

[0103] As a preferred example in the present invention, the aqueous binder may be selected from the group consisting of water glass and colloidal silica based binders.

[0104] Water glass is an aqueous solution of sodium silicate obtained by dissolving silicon dioxide and alkali. It has high viscosity and is transparent and is used as a heat-resistant adhesive and a binder for self-hardening molds.

[0105] For example, water glass contains potassium, lithium, and sodium silicate, and its products include SFR-0582, ECO-M500, R-501, SMC-374-1, and PS-C200 from Youngil Chemical.

[0106] Colloidal silica is a spherical, non-crystalline, non-porous silica particle of colloidal size dispersed in an aqueous or organic solution. Colloidal silica has numerous OH- ions on its surface and forms siloxane bonds (Si-O-Si) internally, resulting in properties such as bonding properties, heat resistance, film-forming properties, and adsorptive properties.

[0107] For example, there are several types of colloidal silica-based binders depending on the method of adding the binder, and products such as NH-64U-1 from Youngil Chemical Co., Ltd.

[0108] For water glass or colloidal silica-based binders, they are vulnerable to moisture after curing, so it is recommended to add SiO2 or Al2O3, etc., to adjust the molar ratio with K and Na to 2 to 5 times or more. Since the ratio of alkali metal and SiO2 varies depending on the binder material, add accordingly.

[0109] The above-mentioned water-based binder uses water during coating application, so it produces fewer hazardous substances and is prone to glazing at high temperatures during operation. However, because it has poor spreadability compared to oil-based binders, primer treatment may be advisable.

[0110] As a preferred example in the present invention, the pyrolysis compound may be included in an amount of 50 to 90 parts by weight per 100 parts by weight of the total composition.

[0111] If the pyrolysis compound is included in an amount less than 50 parts by weight, the effect of preventing thermal runaway through absorption of decomposition energy cannot be sufficiently provided, and if it is included in an amount greater than 90 parts by weight, the binding properties of the binder deteriorate, making it difficult to secure bonding strength with the battery.

[0112]

[0113] Referring to Fig. 1, the battery (B) of the present invention has a coating layer (C) formed on the outer surface using the coating composition for the battery. In a preferred embodiment, the coating composition for the battery of the present invention can be applied to the outer surface of the battery instead of a protective organic material (cover sheet). For example, the application can be performed by spray coating or dipping. In another embodiment, the application of the present embodiment includes a potting method, and includes a method of manufacturing a sheet including the coating composition for the battery of the present embodiment and attaching it to the outer surface of the battery, and the application of the present embodiment can include various known methods for forming a composition layer on the outer surface of the battery.

[0114] As a preferred example in the present invention, the coating layer (C) may have a thickness of 10 to 500 μm.

[0115] If the thickness of the coating layer (C) is less than 10 ㎛, the heat absorption effect of the present invention is not sufficient, and problems may arise in the thickness uniformity map from the perspective of deviation in the actual applied thickness.

[0116] If the thickness of the coating layer (C) is greater than 500 ㎛, the module size may increase when manufacturing the battery module.

[0117] As a preferred example in the present invention, the battery (B) may be a lithium-ion battery. For example, a cylindrical lithium-ion battery has a structure in which a rounded electrode plate is inserted into the interior of a cylindrical case, i.e., a can, and a positive electrode and a negative electrode are respectively installed at opposite ends of the can. The coating layer (C) of the present invention may be formed on the outer side of the can.

[0118]

[0119] A coating composition for a battery according to the present invention can be prepared as follows.

[0120] It can be manufactured by weighing a powdered pyrolysis compound, weighing a liquid or solid binder, and mixing them using a ball mill or homomixer.

[0121] Water-based binders are generally supplied in liquid form, while oil-based binders are supplied in either liquid or solid form. For example, polysilazane binders are supplied in liquid form.

[0122] A dispersant is included when mixing the pyrolysis compound and the binder, and as an example, a phosphoric acid polyester series dispersant can be used.

[0123]

[0124] Hereinafter, various examples of the coating composition for a battery of the present invention and the oxygen torch evaluation results for these are presented (see Table 4).

[0125] <Example 1>

[0126] A coating composition prepared by mixing 100 parts by weight of Durazane 1500 as a binder, 4 parts by weight of CaCO3680 as a pyrolysis compound, and 4 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0127] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 15 seconds.

[0128] Oxygen torch testing is a method for comparing heat resistance by measuring the time it takes for a target (a metal sheet with a coating layer formed on its surface) to melt and form a hole when a flame is applied to the target using a gas torch at approximately 1400°C. This method can be used to assess the potential delay time in the event of battery thermal runaway.

[0129] <Example 2>

[0130] A coating composition prepared by mixing 100 parts by weight of Durazane 1500 as a binder, 3 parts by weight of MgCO3560 as a pyrolysis compound, and 3 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0131] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 30 seconds.

[0132] <Example 3>

[0133] A coating composition prepared by mixing 200 parts by weight of TSR 117 as a binder, 80 parts by weight of CaCO36 as a pyrolysis compound, and 4 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0134] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 14 seconds.

[0135] <Example 4>

[0136] A coating composition 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 a pyrolysis compound, and 3 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0137] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 23 seconds.

[0138] <Example 5>

[0139] A coating composition prepared by mixing 370 parts by weight of SFR-0582 as a binder, 80 parts by weight of CaCO3680 as a pyrolysis compound, and 4 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0140] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 16 seconds.

[0141] <Example 6>

[0142] A coating composition prepared by mixing 370 parts by weight of SFR-0582 as a binder, 560 parts by weight of MgCO3 as a pyrolysis compound, and 4 parts by weight of a dispersant was applied to a 0.5 t thick metal plate to form a coating layer with a thickness of 50 ㎛.

[0143] As a result of the oxygen torch evaluation of the coating composition for batteries, the melting time was measured to be 29 seconds.

[0144] MaterialRef. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Durazane 1500-100100----TSR 117---200200--SFR-0582-----370370MgCO3--560-300-560CaCO3-680-680250680-Dispersant-434344Coating thickness (㎛)-50505050505050 Oxygen torch evaluation (Melting Time, second)9153014231629

[0145] (The content of each component in the examples is by weight)

[0146] <Evaluation Results>

[0147] As a result of the oxygen torch evaluation, it can be seen that if the melting time is 9 seconds or longer (Ref.), it can provide effects such as heat absorption, explosion prevention, and heat transfer reduction during thermal runaway of the battery.

[0148] It was confirmed that the battery coating compositions of Examples 1 to 6 all have a melting time of 9 seconds or more (Ref.) as a result of an oxygen torch evaluation, providing good heat absorption, explosion prevention, and heat transfer reduction effects.

[0149]

[0150] The embodiments presented above are merely illustrative. Those skilled in the art will be able to devise various modifications and variations to the presented embodiments without departing from the technical spirit of the present invention. The scope of the present invention is not limited by such modifications and variations.

Claims

1. A coating composition for an external surface of a battery for preventing thermal runaway of a battery, comprising a pyrolysis compound selected from the group consisting of carbonates, hydroxides, bicarbonates and combinations thereof, and a binder selected from the group consisting of oily binders and water-based binders.

2. In paragraph 1, The above carbonate is, A coating composition for an external surface of a battery for preventing thermal runaway of a battery, the coating composition being selected from the group consisting of BeCO3, CaCO3, Li2CO3, MgCO3, SrCO3, Na2CO3, K2CO3, CaCO3, BaCO3, RaCO3 and combinations thereof.

3. In paragraph 1, The above hydroxide is, A coating composition for an external surface of a battery for preventing thermal runaway of a battery, the coating composition being selected from the group consisting of Be(OH)2, Mg(OH)2, Al(OH)3, Ca(OH)2, Sr(OH)2, Ba(OH)2 and combinations thereof.

4. In paragraph 1, The above bicarbonate is, A coating composition for an external surface of a battery for preventing thermal runaway of a battery, the coating composition being selected from the group consisting of NaHCO3, KHCO3, Ca(HCO3)2, Mg(HCO3)2, LiHCO3, Sr(HCO3)2, Ba(HCO3)2, NH4HCO3 and combinations thereof.

5. In paragraph 1, The above-mentioned meteor binder, A coating composition for an external surface of a battery for preventing thermal runaway of a battery, characterized in that it comprises a Si-O backbone in a cured state in an environment containing O2 or H2O.

6. In paragraph 1, The above-mentioned meteor binder, A coating composition for the outer surface of a battery for preventing thermal runaway of a battery, characterized in that the composition is selected from the group consisting of a siloxane series binder and a polysilazane series binder.

7. In paragraph 1, The above mercury binder, A coating composition for an outer surface of a battery for preventing thermal runaway of a battery, characterized in that the composition is selected from the group consisting of water glass and colloidal silica based binders.

8. In paragraph 1, The above pyrolysis compound is, A coating composition for the outer surface of a battery for preventing thermal runaway of a battery, characterized in that it comprises 50 to 90 parts by weight per 100 parts by weight of the total composition.

9. A battery having a coating layer formed on the outer surface of the battery using a coating composition for preventing thermal runaway of the battery according to any one of claims 1 to 8.

10. In paragraph 9, A battery characterized in that the coating layer has a thickness of 10 to 500 ㎛.

11. In paragraph 9, A battery characterized in that the above battery is a lithium-ion battery.

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