KR102217104B1 - Lithium secondary battery having improved stability - Google Patents

Abstract

The present invention relates to a lithium secondary battery with improved stability, wherein the lithium secondary battery includes a phase change material (PCM) in a gasket, so that when high temperature heat is generated inside the lithium secondary battery, a phase change material (PCM) absorbs heat, lowers the temperature of the gasket and prevents thermal deformation. Accordingly, side reactions due to thermal deformation of the gasket and explosion of the cell may be prevented, and a lithium secondary battery with improved thermal stability may be provided.

Description

Lithium secondary battery having improved stability}

The present invention relates to a lithium secondary battery with improved stability.

Recently, as the technology development and demand for portable devices such as portable computers, portable telephones, and cameras increase, the demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, many studies have been conducted on lithium secondary batteries that exhibit high energy density and operating potential, have a long cycle life, and a low self-discharge rate, and are widely commercialized and used.

However, when a lithium secondary battery is overcharged due to misuse or failure of a charger, or an internal short circuit occurs due to a design defect, penetration, or external impact of the battery itself, the temperature of the battery may increase rapidly. When the temperature of the battery rises rapidly, the battery becomes very unstable due to reaction between the electrolyte and lithium or oxidation of the anode, and the solvent of the electrolyte is decomposed to generate gas, and the decomposition gas of the solvent is ignited. Can lead to an explosion.

When the lithium secondary battery rises to a high temperature of 100°C or higher, the current interrupt device (CID), which is a safety device inside the battery, blocks the flow of current so that the reaction does not occur.

However, the internal components of the battery may be melted by the already generated high-temperature heat, resulting in a side reaction.In particular, when the gasket existing between the battery case and the cap assembly is melted, the positive electrode and the negative electrode are connected and reacted again. Since this occurs, there is a problem in that the cell explosion may occur despite the CID.

The present invention is to provide a lithium secondary battery with improved thermal stability at high temperature, a battery module and a battery pack including the same.

An electrode assembly having an anode, a cathode, and a separator interposed between the anode and the cathode; A battery case in which the electrode assembly is embedded and an upper opening is formed; A cap assembly capable of sealing an upper opening of the battery case; And a gasket interposed between the battery case and the cap assembly, wherein the gasket provides a lithium secondary battery including a phase change material (PCM) therein.

In addition, the present invention provides a battery module and a battery pack including the lithium secondary battery.

According to the present invention, the phase change material (PCM) is included in the gasket sealing the battery case and the cap assembly, so that when high temperature heat is generated inside the lithium secondary battery, the phase change material (PCM) absorbs heat and It can lower the temperature and prevent thermal deformation. Accordingly, side reactions due to thermal deformation of the gasket and explosion of the cell may be prevented, and a lithium secondary battery with improved thermal stability may be provided.

1 is a cross-sectional view of a lithium secondary battery according to an embodiment of the present invention.
Fig. 2 is a schematic diagram showing an enlarged first embodiment of a portion'A' in Fig. 1.
FIG. 3 is a schematic diagram showing an enlarged second embodiment of a portion'A' in FIG. 1.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. In this case, the terms or words used in the specification and claims should not be interpreted as being limited to a conventional or dictionary meaning, and the inventor appropriately defines the concept of the term in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

The accompanying drawings are for clarifying the present invention, and are not limited to the embodiments of the drawings. The shapes and sizes of elements in the drawings may be exaggerated for a more clear description, parts not related to the description will be omitted, and elements having the same function within the scope of the same idea will be described with the same reference numerals.

1 is a cross-sectional view of a lithium secondary battery according to an embodiment of the present invention.

Referring to FIG. 1, a rechargeable lithium battery 100 according to an embodiment of the present invention includes an electrode assembly 200, a battery case 300 in which the electrode assembly 200 is embedded and having an upper opening formed therein, and the battery case. A cap assembly 400 capable of sealing the upper opening of the 300 and a gasket 350 interposed between the battery case 300 and the cap assembly 400, and the inside of the gasket 350 It includes a phase change material (PCM).

The electrode assembly 200 includes a positive electrode 210, a negative electrode 220, and a separator 230 interposed between the positive electrode 210 and the negative electrode 220, and a positive electrode in the form of a sheet coated with an active material on a current collector. It may be a jelly-roll type wound by interposing the separator 230 between the 210 and the cathode 220. The jelly-roll type electrode assembly is easy to manufacture, has a high energy density per weight, and is easily stored in a battery case, but is not necessarily limited to a jelly-roll type.

The battery case 300 accommodates the electrode assembly 200 together with an electrolyte, and a cap assembly 400 is formed at an upper opening of the battery case 300 to seal the battery case 300.

The cap assembly 400 includes safety devices such as a safety vent 500 for discharging high-pressure gas, a current interrupt device (CID) that blocks current, and a top-cap that protects these devices. ) May be included, and the cap assembly 400 may be sealedly coupled to the battery case 300 by the gasket 350.

Lithium secondary batteries generate heat inside the battery due to overcharging due to misuse and failure of the charger, defects in the design of the battery itself, penetration, external shock, or internal short circuit due to deformation due to repeated expansion and contraction of the electrode assembly. Symptoms may occur. The conventional lithium secondary battery has a problem such as melting of internal components of the battery due to this heat generation phenomenon.

When the lithium secondary battery generates heat and rises to a high temperature of 100° C. or more, the conductive pattern of the current blocking element is cut off, thereby blocking current.

However, even when the current blocking element is operated, there is a problem that the gasket is still melted at a high temperature, and when the gasket is melted, the cap assembly connected to the positive electrode and the battery case connected to the negative electrode come into contact with each other, resulting in re-reaction. Therefore, there is a problem in that an explosion of the lithium secondary battery may occur.

Accordingly, in the present invention, the phase change material (PCM) is included in the gasket 350 of the lithium secondary battery, so that when high temperature heat is generated inside the lithium secondary battery, the phase change material (PCM) absorbs heat to the gasket. To reduce the temperature of the gasket and to prevent thermal deformation of the internal accessories.

Accordingly, side reactions and explosion of the cell due to thermal deformation of the gasket and the internal components of the battery may be prevented, and a lithium secondary battery with improved thermal stability may be provided.

The phase change material (PCM) refers to a material used for the purpose of storing energy or maintaining a constant temperature by using the effect of absorbing or releasing latent heat of the material. Here, the latent heat is the heat that maintains the same temperature and absorbs or releases when a substance changes phase, that is, from solid to liquid or from liquid to solid, from liquid to gas, or from gas to liquid, and latent heat is It is much greater than the amount of sensible heat (heat absorbed or released in the absence of a phase change).

Specifically, the phase change material PCM may increase or decrease the ambient temperature by emitting heat or absorbing heat while changing a phase in a corresponding temperature range in which the phase change occurs. For example, when a phase change material (PCM) of 100°C is used, when the internal temperature of the lithium secondary battery reaches 100°C, an endothermic reaction to the phase change material (PCM) occurs, thereby lowering the temperature inside the lithium secondary battery. .

The phase change material (PCM) according to the present invention may be any one or a mixture of two or more selected from the group consisting of hydrated inorganic materials, paraffinic hydrocarbons, and organic acids.

The inorganic material in the hydrate form is NaNH ₄ SO ₄ ·2H ₂ O, Na ₂ SO ₄ ·10H ₂ O, Na ₂ SiO ₃ ·5H ₂ O, Na ₃ PO ₄ ·12H ₂ O, Na(CH ₃ COO) ·3H ₂ O, NaHPO ₄ 12H ₂ O, K ₂ HPO ₄ 3H ₂ O, Fe(NO ₃ ) ₃ 9H ₂ O, FeCl ₃ 2H ₂ O, Fe ₂ O _{3 4} SO ₄ 9H ₂ O, Ca (NO ₃ ) ₂ ·3H ₂ O, CaCl ₂ ·6H ₂ O, K ₂ HPO ₄ ·3H ₂ O and K ₃ PO ₄ ·7H ₂ O It may be any one or a mixture of two or more selected from the group consisting of.

The paraffinic hydrocarbon is n-octacoic acid, n-heptacoic acid, n-pentacoic acid, n-tetracoic acid, n-trichoic acid, n-docoic acid, n-heneicoic acid, n-eicoic acid, n-nona It may be any one or a mixture of two or more selected from the group consisting of decane, n-octadecane, n-heptadecane, n-hexadecane, n-pentadecane, n-tetradecane and n-tridecane.

The organic acid may be any one or a mixture of two or more selected from the group consisting of n-octanoic acid, tartaric acid, oxalic acid, acetic acid, lactic acid and chloroacetic acid.

The phase change material (PCM) according to an embodiment of the present invention may have a phase transition temperature of 45°C to 150°C. The phase change material (PCM) may exhibit an endothermic reaction of absorbing heat due to a phase change from solid to liquid at a temperature of 45°C to 150°C. More preferably, the phase change material (PCM) may have a phase transition temperature of 60°C to 150°C, and most preferably 80°C to 150°C.

Accordingly, even if a heat generation phenomenon of the lithium secondary battery occurs, the internal temperature of the lithium secondary battery can be prevented from rising above 150°C, and thermal deformation of the gasket at a temperature exceeding 150°C can be prevented. Stability can be improved.

The gasket 350 may include the phase change material (PCM). In this case, the form of the phase change material (PCM) may be that the gasket itself is made of a phase change material (PCM), or the phase change material ( PCM) may be dispersed in the gasket, or may include a phase change material (PCM) layer in the gasket, but is not particularly limited thereto.

Hereinafter, a form of including a phase change material (PCM) in a gasket according to a preferred embodiment of the present invention will be described with reference to the drawings.

Fig. 2 is a schematic diagram showing an enlarged first embodiment of a portion'A' in Fig. 1.

Referring to FIG. 2, the gasket 350 according to the first embodiment of the present invention includes a polymer resin 10, and the phase change material 11 may be dispersed in the polymer resin 10.

The polymer resin 10 may be a heat-resistant polymer generally used as a gasket material, for example, polyester, polybutylene, polyethylene, polypropylene, polystyrene, nylon, polycaprolactone, polyethylene terephthalate, Any one or more selected from the group consisting of polyurethane, gelatin, chitosan, cellulose, polymethyl methacrylate, and derivatives thereof may be included, and the present invention is not particularly limited thereto.

Due to the polymer resin 10, insulation and sealing properties between the cap assembly 400 and the battery case 300 in the lithium secondary battery may be secured.

The phase change material 11 dispersed in the polymer resin 10 may be particulate, and a coating layer 12 including a heat-resistant polymer may be further formed on the surface of the phase change material 11.

The coating layer 12 serves to prevent a problem due to the flowability of the phase change material converted to a liquid when the phase change material 11 changes from a solid to a liquid. For example, if a phase change material (PCM) with a phase transition temperature of 100°C is used, when the internal temperature of the lithium secondary battery reaches 100°C, an endothermic reaction to the phase change material (PCM) occurs, lowering the ambient temperature and reducing the phase change. Substances can phase transition from solid to liquid, resulting in flowability. At this time, the coating layer 12 containing a heat-resistant polymer having a heat deformation temperature higher than 100°C does not increase in temperature due to the endothermic reaction of the phase change material (PCM) and does not undergo heat deformation, so the flowability of the phase change material Can be prevented.

The heat-resistant polymer included in the coating layer 12 is not particularly limited as long as it does not interfere with heat transfer of the phase change material 11 to the outside, and can prevent the flowability of the phase change material, for example, Any one or more selected from the group consisting of polyester, polybutylene, polyethylene, polypropylene, polystyrene, nylon, polycaprolactone, polyethylene terephthalate, polyurethane, gelatin, chitosan, cellulose, polymethyl methacrylate, and derivatives thereof It may include, and may be the same material as the polymer resin 10 forming the gasket, or may be a different material. Preferably, the heat-resistant polymer may be one having a heat deformation temperature higher than the phase transition temperature of the phase change material 11.

The thickness of the coating layer 12 may vary from 1 nm to 1 mm depending on the size of the phase change material 11, and the phase change material 11 inside the coating layer 12 transfers heat to the outside of the coating layer 12. It is not particularly limited as long as it is a thickness that does not interfere with the smooth operation.

FIG. 3 is an enlarged schematic diagram illustrating a second embodiment of a portion'A' in FIG. 1.

3, the gasket 350 according to the second embodiment of the present invention covers a phase change material layer 21 including a phase change material (PCM) and an outer surface of the phase change material layer 21 , And a protective layer 22 comprising a heat-resistant polymer.

The phase change material layer 21 may be entirely made of a phase change material (PCM), or may be in a form in which a particle phase change material (PCM) is dispersed in a polymer resin like the gasket of the first embodiment. have.

When the phase change material (PCM) of the phase change material layer 21 changes from a solid to a liquid, the protective layer 22 prevents a problem due to the flowability of the phase change material. In order to prevent the flowability of the phase change material, the protective layer 22 preferably covers all the outer surfaces of the phase change material layer 21.

The heat-resistant polymer included in the protective layer 22 is not particularly limited as long as it does not interfere with the heat transfer of the phase change material layer 21 to the outside, and can prevent the flowability of the phase change material. For example, any selected from the group consisting of polyester, polybutylene, polyethylene, polypropylene, polystyrene, nylon, polycaprolactone, polyethylene terephthalate, polyurethane, gelatin, chitosan, cellulose, polymethyl methacrylate and derivatives thereof It may contain more than one. Preferably, the heat-resistant polymer may be one having a heat deformation temperature higher than the phase transition temperature of the phase change material 11.

By forming the protective layer 22, the flowability of the phase change material can be prevented, and insulation and sealing properties between the cap assembly 400 and the battery case 300 in the lithium secondary battery can be secured.

The thickness of the protective layer 22 may be 10% to 20% of the thickness of the phase change material layer 21, and may exist variously within the above range according to the thickness of the phase change material layer 21, and the phase change If the thickness of the phase change material (PCM) of the material layer 21 does not interfere with smooth heat transfer to the outside of the protective layer 12, there is no particular limitation.

The phase change material (PCM) according to an embodiment of the present invention may be included in an amount of 10 to 50% by weight based on the total weight of the gasket.

When the phase change material (PCM) is included in an amount of less than 10% by weight of the total weight of the gasket, it cannot sufficiently absorb heat generated inside the secondary battery, and thus cannot prevent thermal deformation of the gasket, etc., and thus the electrolyte may leak or There may be a problem that a short circuit between the anode and the cathode occurs. In addition, when the phase change material (PCM) is included in excess of 50% by weight with respect to the total weight of the gasket, the effect of improving thermal stability is insufficient, whereas the flowability of the phase change material (PCM) at high temperature increases, The insulation and sealing properties of the gasket may be deteriorated.

Meanwhile, the electrode to be applied to the lithium secondary battery of the present invention is not particularly limited, and may be manufactured according to a conventional method known in the art.

The positive electrode 210 of the electrode assembly 200 may be manufactured by applying a slurry made by mixing a positive electrode mixture including a positive electrode active material, a conductive material, and a binder in an organic solvent on a positive electrode current collector, followed by drying and rolling, The negative electrode 220 may be prepared by applying a slurry prepared by mixing a negative electrode mixture including a negative electrode active material, a conductive material, and a binder in an organic solvent on a negative electrode current collector, followed by drying and rolling.

The positive electrode active material is not particularly limited, but a lithium transition metal oxide may be specifically used. Examples of the lithium transition metal oxide include lithium cobalt oxide such as LiCoO ₂ , lithium nickel cobalt manganese composite oxide such as LiNi _x Co _y Mn _z O ₂ , lithium nickel oxide such as LiNiO ₂ , LiMn ₂ Lithium manganese oxides such as O _4, etc. may be mentioned, and these may be used alone or in combination of a plurality of them.

As the negative active material, a carbon material, lithium metal, silicon, tin, or the like, through which lithium ions can be occluded and released, may be used. Preferably, a carbon material may be used, and both low crystalline carbon and high crystalline carbon may be used as the carbon material. Typical low crystalline carbons include soft carbon and hard carbon, and high crystalline carbons include natural graphite, kish graphite, pyrolytic carbon, and liquid crystal pitch-based carbon fiber. (mesophase pitch based carbon fiber), mesocarbon microbeads, mesophase pitches, and high-temperature calcined carbons such as petroleum or coal tar pitch derived cokes are typical.

The current collector is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel , Nickel, titanium, silver, or the like may be used.

As the binder, polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidenefluoride, polyacrylonitrile, polymethylmethacrylate, Polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), Various kinds of binder polymers, such as sulfonated EPDM, styrene butadiene rubber (SBR), fluorine rubber, polyacrylic acid, and polymers in which hydrogen is substituted with Li, Na, or Ca, or various copolymers, are used. I can.

The conductive material is not particularly limited as long as it can be generally used in the art, but, for example, artificial graphite, natural graphite, carbon black, acetylene black, Ketjen black, Denka black, thermal black, channel black, carbon fiber, metal Fiber, aluminum, tin, bismuth, silicon, antimony, nickel, copper, titanium, vanadium, chromium, manganese, iron, cobalt, zinc, molybdenum, tungsten, silver, gold, lanthanum, ruthenium, platinum, iridium, titanium oxide, polyaniline , Polythiophene, polyacetylene, polypyrrole, or a combination thereof may be applied, and in general, a carbon black-based conductive material may be used.

As the separator 230 in the electrode assembly 200, any commonly used porous substrate may be used. For example, a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto.

Examples of the polyolefin-based porous membrane include polyolefin-based polymers such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene, polyolefin-based polymers such as polypropylene, polybutylene, and polypentene, respectively, or a mixture of them There is one membrane. As the nonwoven fabric, in addition to the polyolefin nonwoven fabric, for example, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate ), polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc., either alone or Nonwoven fabrics formed of polymers obtained by mixing them are exemplified. The structure of the nonwoven fabric may be a spunbond nonwoven fabric composed of long fibers or a melt blown nonwoven fabric.

The electrolyte of the lithium secondary battery according to the present invention may include a non-aqueous organic solvent and a metal salt.

As the non-aqueous organic solvent, for example, propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile , Dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma-butyrolactone, or a mixture thereof may be used. .

The metal salt may be a lithium salt, and the lithium salt is a material that is easily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF _{3 SO 3, LiCF 3 CO 2,} LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, 4-phenyl Lithium borate, imide, and the like can be used.

The lithium secondary battery according to the present invention may be a cylindrical, rectangular, pouch type secondary battery, but is not limited thereto as long as it corresponds to a charge/discharge device.

In addition, the present invention provides a battery module including the lithium secondary battery as a unit cell and a battery pack including the same. The battery module and the battery pack may be used as a power source for a device such as a mobile electronic device including the lithium secondary battery having an excellent stability line at a high temperature.

The battery pack includes a power tool; Electric vehicles including electric vehicles (EV), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Alternatively, it may be used as a power source for one or more medium and large devices selected from the group consisting of power storage systems.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Example 1: PCM-hydrate type inorganic matter

The top cap of the cap assembly and the cylindrical battery case were manufactured using Ni-plated SPCE (cold rolled steel sheet). An opening was formed at the top of the battery case, and an electrode assembly was mounted therein through the opening of the cylindrical battery case.

Thereafter, a gasket was inserted into the upper end of the battery case. The gasket was prepared by dispersing Na ₂ SiO ₃ ·5H ₂ O (phase transition temperature: 72°C), which is a phase change material (PCM) in polyester, and has a thickness of 1 μm on the surface of the Na ₂ SiO ₃ ·5H ₂ O particles. A polyester coating layer was formed. At this time, the phase change material (PCM) Na ₂ SiO ₃ ·5H ₂ O was included in 10% by weight based on the total weight of the gasket.

Thereafter, a current blocking element and a safety vent are coupled to a place in contact with the inside of the gasket, a PTC element and a top cap are mounted, the top end of the battery case is bent inward, and then a crimping and pressing process is performed to perform the 18650 standard ( 10 round lithium secondary batteries having a direct hit of 18 mm and a length of 65 mm) were produced.

Example 2: PCM-paraffinic hydrocarbon

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the phase change material (PCM) was Paraffin 34-Carbons (phase transition temperature: 75.9°C).

Example 3: PCM-organic acid

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the phase change material (PCM) was (CHCO ₂ NH ₃ ) ₂ (phase transition temperature: 102°C).

Example 4: PCM layer/protective layer formation gasket

As a gasket in Example 1, a phase change material layer including a phase change material (PCM) Na ₂ SiO ₃ ·5H ₂ O (phase transition temperature: 72°C) was formed to a thickness of 1 μm, and the outer side of the phase change material layer A lithium secondary battery was manufactured in the same manner as in Example 1, except that a protective layer including polyester was formed with a thickness of 0.2 μm on the side.

Comparative example

A lithium secondary battery was manufactured in the same manner as in Example 1, except that a gasket made of polyester was used as a gasket in Example 1.

< Experimental Example > Thermal stability evaluation

Table 1 shows the results of evaluating thermal stability by storing the lithium secondary batteries prepared in Examples and Comparative Examples in a high-temperature storage chamber at 150° C. for 1 hour.

Example 1 Example 2 Example 3 Example 4 Comparative example Gasket heat deformation X X X X O Whether a short occurs X X X X O

As shown in the results of Table 1, in the comparative example in which the phase change material (PCM) was not included in the gasket, the gasket was deformed at a high temperature, and a short circuit occurred. In Examples 1 to 4 included in, it can be seen that thermal deformation of the gasket does not occur and no short circuit occurs.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of the present invention.

Claims (14)

An electrode assembly having an anode, a cathode, and a separator interposed between the anode and the cathode;
A battery case in which the electrode assembly is embedded and an upper opening is formed;
A cap assembly capable of sealing the upper opening of the battery case; And
Includes; a gasket interposed between the battery case and the cap assembly,
The gasket contains a phase change material (PCM) therein,
The phase change material has a phase transition temperature of 45 ℃ to 150 ℃,
The phase change material is included in an amount of 10% to 50% by weight based on the total weight of the gasket,
The gasket may include a phase change material layer including the phase change material; And a protective layer surrounding the outer surface of the phase change material layer and including a heat-resistant polymer.
The method of claim 1,
The phase change material is a lithium secondary battery of any one or a mixture of two or more selected from the group consisting of hydrated inorganic materials, paraffinic hydrocarbons, and organic acids.
The method of claim 2,
The inorganic substance in the hydrate form is NaNH ₄ SO ₄ ·2H ₂ O, Na ₂ SO ₄ ·10H ₂ O, Na ₂ SiO ₃ ·5H ₂ O, Na ₃ PO ₄ ·12H ₂ O, Na(CH ₃ COO)·3H ₂ O, NaHPO ₄ 12H ₂ O, K ₂ HPO ₄ 3H ₂ O, Fe(NO ₃ ) ₃ 9H ₂ O, FeCl ₃ 2H ₂ O, Fe ₂ O _{3 4} SO ₄ 9H ₂ O, Ca (NO ₃ ) ₂ ·3H ₂ O, CaCl ₂ ·6H ₂ O, K ₂ HPO ₄ ·3H ₂ O and K ₃ PO ₄ ·7H ₂ O Any one selected from the group consisting of or a mixture of two or more lithium secondary batteries .
The method of claim 2,
The paraffinic hydrocarbon is n-octacoic acid, n-heptacoic acid, n-pentacoic acid, n-tetracoic acid, n-trichoic acid, n-docoic acid, n-heneicoic acid, n-eicoic acid, n-nona Decane, n-octadecane, n-heptadecane, n-hexadecane, n-pentadecane, n-tetradecane and a lithium secondary battery of any one or a mixture of two or more selected from the group consisting of n-tridecane.
The method of claim 2,
The organic acid is a lithium secondary battery of any one or a mixture of two or more selected from the group consisting of n-octanoic acid, tartaric acid, oxalic acid, acetic acid, lactic acid and chloroacetic acid.
delete delete delete The method of claim 1,
The heat-resistant polymer is made of polyester, polybutylene, (polyethylene, polypropylene, polystyrene, nylon, polycaprolactone, polyethylene terephthalate, polyurethane, gelatin, chitosan, cellulose, polymethyl methacrylate, and derivatives thereof). Lithium secondary battery comprising at least one selected from the group.
delete delete A battery module comprising the lithium secondary battery of claim 1 as a unit cell.
A battery pack comprising the battery module of claim 12 and used as a power source for a device.
The method of claim 13,
The device is a mobile electronic device battery pack.

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