KR102264631B1 - Secondary battery - Google Patents

Abstract

The present invention relates to a secondary battery capable of preventing performance degradation due to consumption of additives added to an electrolyte solution.
In addition, the present invention provides a can member for accommodating an electrode assembly and an electrolyte, a top cap assembly for sealing the opening of the can member, and the top cap assembly formed in the top cap assembly to be positioned on the inside toward the can member, and the additive inside is heated It is characterized in that it comprises an additive to be put into the electrolyte.

Description

Secondary battery {SECONDARY BATTERY}

The present invention relates to a secondary battery, and more particularly, to a secondary battery capable of preventing performance degradation due to consumption of additives added to an electrolyte solution.

Lithium secondary batteries can be divided into lithium metal batteries, lithium ion batteries, and lithium polymer batteries according to the type of electrolyte.

Here, the lithium secondary battery does not need to use a solid metal exterior, can be manufactured in various sizes and shapes depending on the use, can be manufactured to a thickness of 3 mm or less, and the weight can be reduced by more than 30%, and can be mass-produced and large-sized batteries manufacturing is possible.

For this reason, lithium secondary batteries are currently commercialized and used in various fields.

The secondary battery accommodates an electrode assembly in which a positive electrode, a negative electrode, and a separator are stacked and an electrolyte inside a case forming an exterior.

In addition, the electrolyte is composed of a solvent, an additive, and a lithium salt, and variously tuned additives are used to satisfy the specifications required for secondary batteries used in various fields.

Korean Patent Application Laid-Open No. 10-2004-0009332 discloses an electrolyte for a lithium secondary battery and a lithium secondary battery including the same.

Such a conventional secondary battery has a problem in that when a specific test, such as a cycle or high temperature, is consumed, the additive added to the electrolyte is consumed, resulting in deterioration of battery performance.

Accordingly, the present invention has been devised by the above necessity, and an object of the present invention is to provide a secondary battery capable of adding an additive consumed in an electrolyte solution.

The secondary battery according to the present invention includes a can member for accommodating an electrode assembly and an electrolyte, a top cap assembly for sealing the opening of the can member, and the top cap assembly to be positioned inside the can member, and at a predetermined temperature. It is characterized in that it comprises an additive for introducing the additive into the electrolyte.

The top cap assembly includes an upper gasket exposed to the outside to insulate from the outside of the can member, and a lower gasket positioned inside to insulate the inside of the can member, wherein the addition part is located inside the can member It may be attached to the lower gasket.

The addition unit may include an outer layer that forms an outside and is decomposed at a predetermined temperature, and an additive accommodated inside the outer layer.

The additive includes vinylene carbonate, vinyl ethylene carbonate, fluoro-ethylene carbonate, succinyl nitrile, 1,3-propane sulfone (1,3- propane sultone) and ethylene glycol bis (propionitrile) ether (ethylene glycol bis (propionitrile) ether).

The outer layer may be made of a polyvinyl chloride material.

The predetermined temperature may be 60°C to 80°C.

The outer film may be made of a polypropylene (polypropylene) material.

The predetermined temperature may be 120°C to 130°C.

The addition part 300 may be formed with a thickness (a) of 0.45 mm to 0.55 mm.

According to the present invention, there is an effect of maintaining the battery performance by supplementing the additives consumed in the electrolyte.

According to the present invention, there is an effect of extending the battery life by supplementing the additives consumed in the electrolyte.

According to the present invention, it is possible to select a temperature range for replenishing the additive, so that it is possible to accurately replenish the additive.

According to the present invention, there is an effect that the electrolyte can be supplemented by selecting the necessary additives.

1 is a perspective view illustrating a secondary battery according to an embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view illustrating that the addition part is formed in the top cap assembly by partially enlarging FIG.
FIG. 3 is a cross-sectional view taken along line BB in FIG. 2 so that only the addition part of the secondary battery according to an embodiment of the present invention is visible.

Hereinafter, a secondary battery according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that there is. Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents.

In the drawings, the size of each component or a specific part constituting the component is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. Therefore, the size of each component does not fully reflect the actual size. If it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, such description will be omitted.

1 is a perspective view showing a secondary battery according to an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view showing that an addition part is formed in the top cap assembly by cutting and partially enlarging FIG. 1 along line AA, FIG. 3 is a cross-sectional view taken along line BB in FIG. 2 so that only the addition part of the secondary battery according to an embodiment of the present invention is visible.

1 to 3, the secondary battery according to the present invention includes a can member 100 for accommodating an electrode assembly and an electrolyte, a top cap assembly 200 for sealing the opening of the can member 100, and the It is formed in the top cap assembly 200 so as to be positioned on the inside facing the can member 100, and includes an additive part 300 for injecting the internal additive 320 into the electrolyte at a predetermined temperature.

The electrode assembly is a jelly roll type in which a positive electrode coated with a positive electrode active material, a negative electrode coated with a negative electrode active material, and a separator interposed between the positive and negative electrodes are laminated multiple times, and the laminate in which the positive electrode, the separator, and the negative electrode are laminated is wound in a jelly roll form. can be produced with

The positive electrode may be an aluminum plate, and may include a positive electrode holding part to which a positive electrode active material is applied, and a positive electrode uncoated part to which a positive electrode active material is not applied.

The positive active material may be a lithium-containing transition metal oxide such as _{LiCoO 2} , LiNiO ₂ , LiMnO ₂ , or LiMnO _{4 or a lithium chalcogenide compound.}

The positive electrode holder may be formed by, for example, coating a portion of at least one surface of an aluminum plate with a positive electrode active material, and the remaining portion of the aluminum plate to which the positive electrode active material is not applied may be a positive electrode uncoated region.

A positive electrode tab may be attached to the positive electrode uncoated region.

The negative electrode may be a copper plate, and may include a negative electrode holding part to which an anode active material is applied and a negative electrode uncoated part to which an anode active material is not applied.

A negative electrode tab may be attached to the negative electrode uncoated region.

The negative active material may be crystalline carbon, amorphous carbon, a carbon composite material, a carbon material such as carbon fiber, lithium metal, or a lithium alloy.

The negative electrode holder may be formed by, for example, coating a portion of at least one surface of a copper plate with an anode active material, and the remaining portion of the copper plate to which the anode active material is not applied may become an anode uncoated region.

The separator is, for example, any one substrate selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP), and a copolymer of polyethylene (PE) and polypropylene (PP). It can be prepared by coating the polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP co-polymer).

Although the can member 100 has been described with a prismatic shape in FIG. 1 as an example, in addition, it is possible to protect the electrode assembly and the electrolyte accommodated therein by forming the external appearance of a secondary battery such as a cylindrical shape or a pouch type.

The can member 100 may form an opening at one end to accommodate the electrode assembly 100 through the opening and seal the opened opening with the top cap assembly 200 .

The electrolyte solution may include, for example, a non-aqueous organic solvent and a lithium salt.

The lithium salt can be dissolved in an organic solvent, act as a source of lithium ions in the secondary battery, and promote movement of lithium ions between the positive electrode and the negative electrode.

Examples of lithium salts include LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₃ , Li(CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiClO ₄ , LiAlO ₄ , LiAlCl ₄ , LiN(C _x F _2x+1 SO ₂ )(CyF _2y+1 SO ₂ ), where x and y are natural numbers, LiCl, LiI, and lithium bisoxalate borate ) may include one or more than one type of electrolyte as a supporting electrolyte.

The concentration of the lithium salt in the electrolyte may be changed depending on the use, and is usually used within the range of 0.1M to 2.0M.

In addition, the organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move, and examples thereof include benzene, toluene, fluorobenzene, 1,2-difluorobenzene, 1,3- Difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3- Dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, iodobenzene, 1,2-diiodobenzene, 1,3- Diiodobenzene, 1,4-diiodobenzene, 1,2,3-triiodobenzene, 1,2,4-triiodobenzene, fluorotoluene, 1,2-difluorotoluene, 1 ,3-difluorotoluene, 1,4-difluorotoluene, 1,2,3-trifluorotoluene, 1,2,4-trifluorotoluene, chlorotoluene, 1,2-dichlorotoluene, 1 ,3-dichlorotoluene, 1,4-dichlorotoluene, 1,2,3-trichlorotoluene, 1,2,4-trichlorotoluene, iodotoluene, 1,2-diiodotoluene, 1,3- Diiodotoluene, 1,4-diiodotoluene, 1,2,3-triiodotoluene, 1,2,4-triiodotoluene, R-CN (wherein R is having 2 to 50 carbon atoms) As a hydrocarbon group having a linear, branched or cyclic structure, the hydrocarbon group may include a double bond, an aromatic ring, or an ether bond), dimethylformamide, dimethyl acetate, xylene, cyclohexane, tetrahydrofuran, 2-methyltetrahydrofuran, cyclohexanone, ethanol, isopropyl alcohol, dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, methylpropyl carbonate, propylene carbonate, methyl propionate, ethyl propionate, methyl acetate, ethyl acetate , propyl acetate, dimethoxyethane, 1,3-dioxolane, diglyme, tetraglyme, ethylene carbonate, propylene carbonate, gamma-butyrolactone, sulfolane, valerolactone, decanolide or mevalo One or more types of lactones may be mentioned, but are limited thereto no.

In addition, additives may be included in the electrolyte, and additives added to the electrolyte include vinylene carbonate, vinyl ethylene carbonate, fluoro-ethylene carbonate, and succinyl nitrile. ), 1,3-propane sultone, ethylene glycol bis (propionitrile) ether, and the like.

The top cap assembly 200 may have a size and shape corresponding to at least the opening of the can member 100 .

In addition, the top cap assembly 200 is sealed to the opening of the can member 100 so that the upper gasket 210 exposed to the outside of the can member 100 and the upper gasket 210 face the can member 100 . It may include a lower gasket 230 formed in the.

The lower gasket 230 may be formed in the direction of the can member 100 , and may be positioned inside the can member 100 to insulate from the inside of the can member 100 .

The addition part 300 may be attached to the lower gasket 230 in the direction of the can member 100 so as to be located inside the can member 100 .

In addition, a plurality of addition parts 300 may be attached to the lower gasket 230 , or may be formed in a ring shape, a circle shape, a square shape, a plate shape, etc. to correspond to the shape of the lower gasket 230 or the inner shape of the can member 100 . can make it

The addition unit 300 includes an outer film 310 that forms the outside of the addition unit 300 and is decomposed at a predetermined temperature, and is accommodated inside the outer film 310 and when the outer film 310 is decomposed, the can member ( 100) may include an additive 320 injected into the electrolyte accommodated therein.

The outer film 310 may be made of polyvinyl chloride or polypropylene.

When the outer film 310 is a vinyl chloride resin, it is decomposed at a predetermined temperature of 60° C. to 80° C. and the additive 320 can be added to the electrolyte.

In addition, when the outer film 310 is polypropylene, it is decomposed at a predetermined temperature of 120° C. to 130° C. and the additive 320 may be added to the electrolyte solution.

That is, the outer film 310 may selectively form any one of polyvinyl chloride or polypropylene material in order to inject the additive 320 into the electrolyte at a required temperature.

Additive 320 is vinylene carbonate (vinylene carbonate), vinyl ethylene carbonate (vinyl ethylene carbonate), fluoroethylene carbonate (fluoro-ethylene carbonate), succinic to correspond to the additive added to the electrolyte solution accommodated in the can member 100. Electrolyte by selectively forming any one or more of succinyl nitrile, 1,3-propane sultone, and ethylene glycol bis (propionitrile) ether It can be replenished when the additives added to it are consumed.

That is, when the additive of the electrolyte contained in the secondary battery is consumed in a specific secondary battery test such as a cycle or high temperature, the material of the outer film 310 is selectively formed in consideration of the environment in which the additive is consumed, and in the electrolyte The additive 320 inside the addition unit 300 may be selectively formed in consideration of the components of the consumed additive.

In addition, the addition part 300 may be formed with a thickness (a) of 0.45 mm to 0.55 mm.

That is, when the additive part 300 is formed with a thickness (a) of less than 0.45 mm, the amount of the additive 320 accommodated in the outer film 310 is insufficient, so that the additive consumed in the electrolyte cannot be sufficiently supplemented, and the additive part If the thickness (a) of 300 exceeds 0.55 mm, the thickness of the additive part 300 is too thick, which may affect the design of the secondary battery and add more than the required amount of the additive 320 inside the outer membrane 310. An unnecessary space that can be accommodated may be formed.

As described above, according to the present invention, there is an effect of maintaining the battery performance by supplementing the additives consumed in the electrolyte.

According to the present invention, there is an effect of extending the battery life by supplementing the additives consumed in the electrolyte.

According to the present invention, it is possible to select a temperature range for replenishing the additive, thereby enabling accurate additive replenishment.

According to the present invention, there is an effect that the electrolyte can be supplemented by selecting the necessary additives.

As described above, the secondary battery according to the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings described above, and within the scope of the claims, it is common in the technical field to which the present invention pertains. Various implementations are possible by those with the knowledge of

100: can member
200: top cap assembly
210: upper gasket
230: lower gasket
300: additive
310: outer film
320: additive

Claims (9)

a can member 100 for accommodating the electrode assembly and the electrolyte;
a top cap assembly 200 for sealing the opening of the can member 100; and
an additive part 300 formed in the top cap assembly 200 to be positioned on the inside facing the can member 100 and injecting an additive 320 therein into the electrolyte at a predetermined temperature; including,
The additive part 300 includes an outer film 310 that forms an exterior and is decomposed at a predetermined temperature and an additive 320 accommodated in the outer film 310,
The addition part 300 is formed with a thickness (a) of 0.45 mm or more to supplement the additive 320 in a sufficient amount, and 0.55 mm or less to prevent the formation of unnecessary space,
The top cap assembly 200 includes an upper gasket 210 exposed to the outside to insulate from the outside of the can member 100 and a lower gasket 230 positioned inside to insulate the inside of the can member 100 . Including, the addition part 300 is attached to the lower gasket 230 so as to be located inside the can member 100,
A secondary battery, characterized in that a plurality of the addition part (300) is attached to the lower gasket (230) corresponding to the shape of the lower gasket (230) and the inner shape of the can member (100). delete delete The method according to claim 1,
The additive 320 is vinylene carbonate (vinylene carbonate), vinyl ethylene carbonate (vinyl ethylene carbonate), fluoroethylene carbonate (fluoro-ethylene carbonate), succinyl nitrile (succinyl nitrile), 1,3-propane sulfone (1) ,3-propane sultone), ethylene glycol bis (propionitrile) ether (ethylene glycol bis (propionitrile) ether) secondary battery, characterized in that any one or more. The method according to claim 1,
The outer film 310 is a secondary battery, characterized in that the polyvinyl chloride (polyvinyl chloride) material. 6. The method of claim 5,
The predetermined temperature is a secondary battery, characterized in that 60 ~ 80 ℃. The method according to claim 1,
The outer film 310 is a secondary battery, characterized in that the polypropylene (polypropylene) material. 8. The method of claim 7,
The predetermined temperature is a secondary battery, characterized in that 120 ℃ ~ 130 ℃. delete

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